poc: rust router

- Uses the settlement function (via Mixin) to perform sampling
- Removed the Gas schedule as gasUsed is recorded when sampling
- Remove most function selectors for Curve pools (only exchange is required)
- Allow banning of routes if they often return 0
- Introduce CurveV2Sampler required for SwapRevert sampler

contracts/asset-proxy/CHANGELOG.json

@@ -1,4 +1,22 @@
 [
+    {
+        "timestamp": 1624356181,
+        "version": "3.7.16",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1623382456,
+        "version": "3.7.15",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
     {
         "timestamp": 1622609597,
         "version": "3.7.14",

contracts/asset-proxy/CHANGELOG.md

@@ -5,6 +5,14 @@ Edit the package's CHANGELOG.json file only.
 
 CHANGELOG
 
+## v3.7.16 - _June 22, 2021_
+
+    * Dependencies updated
+
+## v3.7.15 - _June 11, 2021_
+
+    * Dependencies updated
+
 ## v3.7.14 - _June 2, 2021_
 
     * Dependencies updated

contracts/asset-proxy/package.json

@@ -1,6 +1,6 @@
 {
     "name": "@0x/contracts-asset-proxy",
-    "version": "3.7.14",
+    "version": "3.7.16",
     "engines": {
         "node": ">=6.12"
     },
@@ -52,10 +52,10 @@
     "homepage": "https://github.com/0xProject/protocol/tree/main/contracts/protocol",
     "devDependencies": {
         "@0x/abi-gen": "^5.6.0",
-        "@0x/contract-wrappers": "^13.17.0",
+        "@0x/contract-wrappers": "^13.17.2",
         "@0x/contracts-gen": "^2.0.38",
-        "@0x/contracts-test-utils": "^5.4.3",
-        "@0x/contracts-utils": "^4.7.11",
+        "@0x/contracts-test-utils": "^5.4.5",
+        "@0x/contracts-utils": "^4.7.13",
         "@0x/dev-utils": "^4.2.7",
         "@0x/sol-compiler": "^4.7.3",
         "@0x/ts-doc-gen": "^0.0.28",
@@ -80,11 +80,11 @@
     },
     "dependencies": {
         "@0x/base-contract": "^6.4.0",
-        "@0x/contracts-erc1155": "^2.1.32",
-        "@0x/contracts-erc20": "^3.3.11",
-        "@0x/contracts-erc721": "^3.1.32",
-        "@0x/contracts-exchange-libs": "^4.3.32",
-        "@0x/order-utils": "^10.4.24",
+        "@0x/contracts-erc1155": "^2.1.34",
+        "@0x/contracts-erc20": "^3.3.13",
+        "@0x/contracts-erc721": "^3.1.34",
+        "@0x/contracts-exchange-libs": "^4.3.34",
+        "@0x/order-utils": "^10.4.26",
         "@0x/types": "^3.3.3",
         "@0x/typescript-typings": "^5.2.0",
         "@0x/utils": "^6.4.3",

contracts/broker/CHANGELOG.json

@@ -1,4 +1,22 @@
 [
+    {
+        "timestamp": 1624356181,
+        "version": "1.1.34",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1623382456,
+        "version": "1.1.33",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
     {
         "timestamp": 1622609597,
         "version": "1.1.32",

contracts/broker/CHANGELOG.md

@@ -5,6 +5,14 @@ Edit the package's CHANGELOG.json file only.
 
 CHANGELOG
 
+## v1.1.34 - _June 22, 2021_
+
+    * Dependencies updated
+
+## v1.1.33 - _June 11, 2021_
+
+    * Dependencies updated
+
 ## v1.1.32 - _June 2, 2021_
 
     * Dependencies updated

contracts/broker/package.json

@@ -1,6 +1,6 @@
 {
     "name": "@0x/contracts-broker",
-    "version": "1.1.32",
+    "version": "1.1.34",
     "engines": {
         "node": ">=6.12"
     },
@@ -52,14 +52,14 @@
     "homepage": "https://github.com/0xProject/protocol/tree/main/contracts/extensions",
     "devDependencies": {
         "@0x/abi-gen": "^5.6.0",
-        "@0x/contracts-asset-proxy": "^3.7.14",
-        "@0x/contracts-erc20": "^3.3.11",
-        "@0x/contracts-erc721": "^3.1.32",
-        "@0x/contracts-exchange": "^3.2.33",
-        "@0x/contracts-exchange-libs": "^4.3.32",
+        "@0x/contracts-asset-proxy": "^3.7.16",
+        "@0x/contracts-erc20": "^3.3.13",
+        "@0x/contracts-erc721": "^3.1.34",
+        "@0x/contracts-exchange": "^3.2.35",
+        "@0x/contracts-exchange-libs": "^4.3.34",
         "@0x/contracts-gen": "^2.0.38",
-        "@0x/contracts-test-utils": "^5.4.3",
-        "@0x/contracts-utils": "^4.7.11",
+        "@0x/contracts-test-utils": "^5.4.5",
+        "@0x/contracts-utils": "^4.7.13",
         "@0x/sol-compiler": "^4.7.3",
         "@0x/ts-doc-gen": "^0.0.28",
         "@0x/tslint-config": "^4.1.4",
@@ -85,7 +85,7 @@
     },
     "dependencies": {
         "@0x/base-contract": "^6.4.0",
-        "@0x/order-utils": "^10.4.24",
+        "@0x/order-utils": "^10.4.26",
         "@0x/typescript-typings": "^5.2.0",
         "@0x/utils": "^6.4.3",
         "ethereum-types": "^3.5.0"

contracts/coordinator/CHANGELOG.json

@@ -1,4 +1,22 @@
 [
+    {
+        "timestamp": 1624356181,
+        "version": "3.1.35",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1623382456,
+        "version": "3.1.34",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
     {
         "timestamp": 1622609597,
         "version": "3.1.33",

contracts/coordinator/CHANGELOG.md

@@ -5,6 +5,14 @@ Edit the package's CHANGELOG.json file only.
 
 CHANGELOG
 
+## v3.1.35 - _June 22, 2021_
+
+    * Dependencies updated
+
+## v3.1.34 - _June 11, 2021_
+
+    * Dependencies updated
+
 ## v3.1.33 - _June 2, 2021_
 
     * Dependencies updated

contracts/coordinator/package.json

@@ -1,6 +1,6 @@
 {
     "name": "@0x/contracts-coordinator",
-    "version": "3.1.33",
+    "version": "3.1.35",
     "engines": {
         "node": ">=6.12"
     },
@@ -53,12 +53,12 @@
     "homepage": "https://github.com/0xProject/protocol/tree/main/contracts/extensions",
     "devDependencies": {
         "@0x/abi-gen": "^5.6.0",
-        "@0x/contracts-asset-proxy": "^3.7.14",
-        "@0x/contracts-dev-utils": "^1.3.31",
-        "@0x/contracts-erc20": "^3.3.11",
+        "@0x/contracts-asset-proxy": "^3.7.16",
+        "@0x/contracts-dev-utils": "^1.3.33",
+        "@0x/contracts-erc20": "^3.3.13",
         "@0x/contracts-gen": "^2.0.38",
         "@0x/dev-utils": "^4.2.7",
-        "@0x/order-utils": "^10.4.24",
+        "@0x/order-utils": "^10.4.26",
         "@0x/sol-compiler": "^4.7.3",
         "@0x/ts-doc-gen": "^0.0.28",
         "@0x/tslint-config": "^4.1.4",
@@ -84,10 +84,10 @@
     "dependencies": {
         "@0x/assert": "^3.0.27",
         "@0x/base-contract": "^6.4.0",
-        "@0x/contract-addresses": "^6.3.0",
-        "@0x/contracts-exchange": "^3.2.33",
-        "@0x/contracts-test-utils": "^5.4.3",
-        "@0x/contracts-utils": "^4.7.11",
+        "@0x/contract-addresses": "^6.4.0",
+        "@0x/contracts-exchange": "^3.2.35",
+        "@0x/contracts-test-utils": "^5.4.5",
+        "@0x/contracts-utils": "^4.7.13",
         "@0x/json-schemas": "^6.1.3",
         "@0x/types": "^3.3.3",
         "@0x/typescript-typings": "^5.2.0",

contracts/dev-utils/CHANGELOG.json

@@ -1,4 +1,22 @@
 [
+    {
+        "timestamp": 1624356181,
+        "version": "1.3.33",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1623382456,
+        "version": "1.3.32",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
     {
         "timestamp": 1622609597,
         "version": "1.3.31",

contracts/dev-utils/CHANGELOG.md

@@ -5,6 +5,14 @@ Edit the package's CHANGELOG.json file only.
 
 CHANGELOG
 
+## v1.3.33 - _June 22, 2021_
+
+    * Dependencies updated
+
+## v1.3.32 - _June 11, 2021_
+
+    * Dependencies updated
+
 ## v1.3.31 - _June 2, 2021_
 
     * Dependencies updated

contracts/dev-utils/package.json

@@ -1,6 +1,6 @@
 {
     "name": "@0x/contracts-dev-utils",
-    "version": "1.3.31",
+    "version": "1.3.33",
     "engines": {
         "node": ">=6.12"
     },
@@ -43,10 +43,10 @@
     "devDependencies": {
         "@0x/abi-gen": "^5.6.0",
         "@0x/assert": "^3.0.27",
-        "@0x/contracts-asset-proxy": "^3.7.14",
-        "@0x/contracts-erc20": "^3.3.11",
+        "@0x/contracts-asset-proxy": "^3.7.16",
+        "@0x/contracts-erc20": "^3.3.13",
         "@0x/contracts-gen": "^2.0.38",
-        "@0x/contracts-test-utils": "^5.4.3",
+        "@0x/contracts-test-utils": "^5.4.5",
         "@0x/sol-compiler": "^4.7.3",
         "@0x/ts-doc-gen": "^0.0.28",
         "@0x/tslint-config": "^4.1.4",

contracts/erc1155/CHANGELOG.json

@@ -1,4 +1,22 @@
 [
+    {
+        "timestamp": 1624356181,
+        "version": "2.1.34",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1623382456,
+        "version": "2.1.33",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
     {
         "timestamp": 1622609597,
         "version": "2.1.32",

contracts/erc1155/CHANGELOG.md

@@ -5,6 +5,14 @@ Edit the package's CHANGELOG.json file only.
 
 CHANGELOG
 
+## v2.1.34 - _June 22, 2021_
+
+    * Dependencies updated
+
+## v2.1.33 - _June 11, 2021_
+
+    * Dependencies updated
+
 ## v2.1.32 - _June 2, 2021_
 
     * Dependencies updated

contracts/erc1155/package.json

@@ -1,6 +1,6 @@
 {
     "name": "@0x/contracts-erc1155",
-    "version": "2.1.32",
+    "version": "2.1.34",
     "engines": {
         "node": ">=6.12"
     },
@@ -54,7 +54,7 @@
     "devDependencies": {
         "@0x/abi-gen": "^5.6.0",
         "@0x/contracts-gen": "^2.0.38",
-        "@0x/contracts-utils": "^4.7.11",
+        "@0x/contracts-utils": "^4.7.13",
         "@0x/dev-utils": "^4.2.7",
         "@0x/sol-compiler": "^4.7.3",
         "@0x/ts-doc-gen": "^0.0.28",
@@ -81,7 +81,7 @@
     },
     "dependencies": {
         "@0x/base-contract": "^6.4.0",
-        "@0x/contracts-test-utils": "^5.4.3",
+        "@0x/contracts-test-utils": "^5.4.5",
         "@0x/utils": "^6.4.3",
         "@0x/web3-wrapper": "^7.5.3",
         "lodash": "^4.17.11"

contracts/erc20/CHANGELOG.json

@@ -1,4 +1,22 @@
 [
+    {
+        "timestamp": 1624356181,
+        "version": "3.3.13",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1623382456,
+        "version": "3.3.12",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
     {
         "timestamp": 1622609597,
         "version": "3.3.11",

contracts/erc20/CHANGELOG.md

@@ -5,6 +5,14 @@ Edit the package's CHANGELOG.json file only.
 
 CHANGELOG
 
+## v3.3.13 - _June 22, 2021_
+
+    * Dependencies updated
+
+## v3.3.12 - _June 11, 2021_
+
+    * Dependencies updated
+
 ## v3.3.11 - _June 2, 2021_
 
     * Dependencies updated

contracts/erc20/package.json

@@ -1,6 +1,6 @@
 {
     "name": "@0x/contracts-erc20",
-    "version": "3.3.11",
+    "version": "3.3.13",
     "engines": {
         "node": ">=6.12"
     },
@@ -53,8 +53,8 @@
     "devDependencies": {
         "@0x/abi-gen": "^5.6.0",
         "@0x/contracts-gen": "^2.0.38",
-        "@0x/contracts-test-utils": "^5.4.3",
-        "@0x/contracts-utils": "^4.7.11",
+        "@0x/contracts-test-utils": "^5.4.5",
+        "@0x/contracts-utils": "^4.7.13",
         "@0x/dev-utils": "^4.2.7",
         "@0x/sol-compiler": "^4.7.3",
         "@0x/ts-doc-gen": "^0.0.28",

contracts/erc721/CHANGELOG.json

@@ -1,4 +1,22 @@
 [
+    {
+        "timestamp": 1624356181,
+        "version": "3.1.34",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1623382456,
+        "version": "3.1.33",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
     {
         "timestamp": 1622609597,
         "version": "3.1.32",

contracts/erc721/CHANGELOG.md

@@ -5,6 +5,14 @@ Edit the package's CHANGELOG.json file only.
 
 CHANGELOG
 
+## v3.1.34 - _June 22, 2021_
+
+    * Dependencies updated
+
+## v3.1.33 - _June 11, 2021_
+
+    * Dependencies updated
+
 ## v3.1.32 - _June 2, 2021_
 
     * Dependencies updated

contracts/erc721/package.json

@@ -1,6 +1,6 @@
 {
     "name": "@0x/contracts-erc721",
-    "version": "3.1.32",
+    "version": "3.1.34",
     "engines": {
         "node": ">=6.12"
     },
@@ -54,8 +54,8 @@
     "devDependencies": {
         "@0x/abi-gen": "^5.6.0",
         "@0x/contracts-gen": "^2.0.38",
-        "@0x/contracts-test-utils": "^5.4.3",
-        "@0x/contracts-utils": "^4.7.11",
+        "@0x/contracts-test-utils": "^5.4.5",
+        "@0x/contracts-utils": "^4.7.13",
         "@0x/dev-utils": "^4.2.7",
         "@0x/sol-compiler": "^4.7.3",
         "@0x/ts-doc-gen": "^0.0.28",

contracts/exchange-forwarder/CHANGELOG.json

@@ -1,4 +1,22 @@
 [
+    {
+        "timestamp": 1624356181,
+        "version": "4.2.35",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1623382456,
+        "version": "4.2.34",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
     {
         "timestamp": 1622609597,
         "version": "4.2.33",

contracts/exchange-forwarder/CHANGELOG.md

@@ -5,6 +5,14 @@ Edit the package's CHANGELOG.json file only.
 
 CHANGELOG
 
+## v4.2.35 - _June 22, 2021_
+
+    * Dependencies updated
+
+## v4.2.34 - _June 11, 2021_
+
+    * Dependencies updated
+
 ## v4.2.33 - _June 2, 2021_
 
     * Dependencies updated

contracts/exchange-forwarder/package.json

@@ -1,6 +1,6 @@
 {
     "name": "@0x/contracts-exchange-forwarder",
-    "version": "4.2.33",
+    "version": "4.2.35",
     "engines": {
         "node": ">=6.12"
     },
@@ -53,18 +53,18 @@
     "homepage": "https://github.com/0xProject/protocol/tree/main/contracts/extensions",
     "devDependencies": {
         "@0x/abi-gen": "^5.6.0",
-        "@0x/contracts-asset-proxy": "^3.7.14",
-        "@0x/contracts-dev-utils": "^1.3.31",
-        "@0x/contracts-erc1155": "^2.1.32",
-        "@0x/contracts-erc20": "^3.3.11",
-        "@0x/contracts-erc721": "^3.1.32",
-        "@0x/contracts-exchange": "^3.2.33",
-        "@0x/contracts-exchange-libs": "^4.3.32",
+        "@0x/contracts-asset-proxy": "^3.7.16",
+        "@0x/contracts-dev-utils": "^1.3.33",
+        "@0x/contracts-erc1155": "^2.1.34",
+        "@0x/contracts-erc20": "^3.3.13",
+        "@0x/contracts-erc721": "^3.1.34",
+        "@0x/contracts-exchange": "^3.2.35",
+        "@0x/contracts-exchange-libs": "^4.3.34",
         "@0x/contracts-gen": "^2.0.38",
-        "@0x/contracts-test-utils": "^5.4.3",
-        "@0x/contracts-utils": "^4.7.11",
+        "@0x/contracts-test-utils": "^5.4.5",
+        "@0x/contracts-utils": "^4.7.13",
         "@0x/dev-utils": "^4.2.7",
-        "@0x/order-utils": "^10.4.24",
+        "@0x/order-utils": "^10.4.26",
         "@0x/sol-compiler": "^4.7.3",
         "@0x/ts-doc-gen": "^0.0.28",
         "@0x/tslint-config": "^4.1.4",

contracts/exchange-libs/CHANGELOG.json

@@ -1,4 +1,22 @@
 [
+    {
+        "timestamp": 1624356181,
+        "version": "4.3.34",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1623382456,
+        "version": "4.3.33",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
     {
         "timestamp": 1622609597,
         "version": "4.3.32",

contracts/exchange-libs/CHANGELOG.md

@@ -5,6 +5,14 @@ Edit the package's CHANGELOG.json file only.
 
 CHANGELOG
 
+## v4.3.34 - _June 22, 2021_
+
+    * Dependencies updated
+
+## v4.3.33 - _June 11, 2021_
+
+    * Dependencies updated
+
 ## v4.3.32 - _June 2, 2021_
 
     * Dependencies updated

contracts/exchange-libs/package.json

@@ -1,6 +1,6 @@
 {
     "name": "@0x/contracts-exchange-libs",
-    "version": "4.3.32",
+    "version": "4.3.34",
     "engines": {
         "node": ">=6.12"
     },
@@ -81,9 +81,9 @@
     },
     "dependencies": {
         "@0x/base-contract": "^6.4.0",
-        "@0x/contracts-test-utils": "^5.4.3",
-        "@0x/contracts-utils": "^4.7.11",
-        "@0x/order-utils": "^10.4.24",
+        "@0x/contracts-test-utils": "^5.4.5",
+        "@0x/contracts-utils": "^4.7.13",
+        "@0x/order-utils": "^10.4.26",
         "@0x/types": "^3.3.3",
         "@0x/typescript-typings": "^5.2.0",
         "@0x/utils": "^6.4.3",

contracts/exchange/CHANGELOG.json

@@ -1,4 +1,22 @@
 [
+    {
+        "timestamp": 1624356181,
+        "version": "3.2.35",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1623382456,
+        "version": "3.2.34",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
     {
         "timestamp": 1622609597,
         "version": "3.2.33",

contracts/exchange/CHANGELOG.md

@@ -5,6 +5,14 @@ Edit the package's CHANGELOG.json file only.
 
 CHANGELOG
 
+## v3.2.35 - _June 22, 2021_
+
+    * Dependencies updated
+
+## v3.2.34 - _June 11, 2021_
+
+    * Dependencies updated
+
 ## v3.2.33 - _June 2, 2021_
 
     * Dependencies updated

contracts/exchange/package.json

@@ -1,6 +1,6 @@
 {
     "name": "@0x/contracts-exchange",
-    "version": "3.2.33",
+    "version": "3.2.35",
     "engines": {
         "node": ">=6.12"
     },
@@ -53,13 +53,13 @@
     "homepage": "https://github.com/0xProject/protocol/tree/main/contracts/protocol",
     "devDependencies": {
         "@0x/abi-gen": "^5.6.0",
-        "@0x/contracts-asset-proxy": "^3.7.14",
-        "@0x/contracts-exchange-libs": "^4.3.32",
+        "@0x/contracts-asset-proxy": "^3.7.16",
+        "@0x/contracts-exchange-libs": "^4.3.34",
         "@0x/contracts-gen": "^2.0.38",
-        "@0x/contracts-multisig": "^4.1.33",
-        "@0x/contracts-staking": "^2.0.40",
-        "@0x/contracts-test-utils": "^5.4.3",
-        "@0x/contracts-utils": "^4.7.11",
+        "@0x/contracts-multisig": "^4.1.35",
+        "@0x/contracts-staking": "^2.0.42",
+        "@0x/contracts-test-utils": "^5.4.5",
+        "@0x/contracts-utils": "^4.7.13",
         "@0x/dev-utils": "^4.2.7",
         "@0x/sol-compiler": "^4.7.3",
         "@0x/ts-doc-gen": "^0.0.28",
@@ -89,11 +89,11 @@
     },
     "dependencies": {
         "@0x/base-contract": "^6.4.0",
-        "@0x/contracts-dev-utils": "^1.3.31",
-        "@0x/contracts-erc1155": "^2.1.32",
-        "@0x/contracts-erc20": "^3.3.11",
-        "@0x/contracts-erc721": "^3.1.32",
-        "@0x/order-utils": "^10.4.24",
+        "@0x/contracts-dev-utils": "^1.3.33",
+        "@0x/contracts-erc1155": "^2.1.34",
+        "@0x/contracts-erc20": "^3.3.13",
+        "@0x/contracts-erc721": "^3.1.34",
+        "@0x/order-utils": "^10.4.26",
         "@0x/utils": "^6.4.3",
         "lodash": "^4.17.11"
     },

contracts/extensions/CHANGELOG.json

@@ -1,4 +1,22 @@
 [
+    {
+        "timestamp": 1624356181,
+        "version": "6.2.29",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1623382456,
+        "version": "6.2.28",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
     {
         "timestamp": 1622609597,
         "version": "6.2.27",

contracts/extensions/CHANGELOG.md

@@ -5,6 +5,14 @@ Edit the package's CHANGELOG.json file only.
 
 CHANGELOG
 
+## v6.2.29 - _June 22, 2021_
+
+    * Dependencies updated
+
+## v6.2.28 - _June 11, 2021_
+
+    * Dependencies updated
+
 ## v6.2.27 - _June 2, 2021_
 
     * Dependencies updated

contracts/extensions/package.json

@@ -1,6 +1,6 @@
 {
     "name": "@0x/contracts-extensions",
-    "version": "6.2.27",
+    "version": "6.2.29",
     "engines": {
         "node": ">=6.12"
     },
@@ -53,16 +53,16 @@
     "homepage": "https://github.com/0xProject/protocol/tree/main/contracts/extensions",
     "devDependencies": {
         "@0x/abi-gen": "^5.6.0",
-        "@0x/contracts-asset-proxy": "^3.7.14",
-        "@0x/contracts-dev-utils": "^1.3.31",
-        "@0x/contracts-erc20": "^3.3.11",
-        "@0x/contracts-erc721": "^3.1.32",
-        "@0x/contracts-exchange": "^3.2.33",
-        "@0x/contracts-exchange-libs": "^4.3.32",
+        "@0x/contracts-asset-proxy": "^3.7.16",
+        "@0x/contracts-dev-utils": "^1.3.33",
+        "@0x/contracts-erc20": "^3.3.13",
+        "@0x/contracts-erc721": "^3.1.34",
+        "@0x/contracts-exchange": "^3.2.35",
+        "@0x/contracts-exchange-libs": "^4.3.34",
         "@0x/contracts-gen": "^2.0.38",
-        "@0x/contracts-utils": "^4.7.11",
+        "@0x/contracts-utils": "^4.7.13",
         "@0x/dev-utils": "^4.2.7",
-        "@0x/order-utils": "^10.4.24",
+        "@0x/order-utils": "^10.4.26",
         "@0x/sol-compiler": "^4.7.3",
         "@0x/ts-doc-gen": "^0.0.28",
         "@0x/tslint-config": "^4.1.4",
@@ -91,7 +91,7 @@
     },
     "dependencies": {
         "@0x/base-contract": "^6.4.0",
-        "@0x/contracts-test-utils": "^5.4.3",
+        "@0x/contracts-test-utils": "^5.4.5",
         "@0x/typescript-typings": "^5.2.0",
         "ethereum-types": "^3.5.0"
     },

contracts/integrations/package.json

@@ -1,6 +1,6 @@
 {
     "name": "@0x/contracts-integrations",
-    "version": "2.7.48",
+    "version": "2.7.53",
     "private": true,
     "engines": {
         "node": ">=6.12"
@@ -53,21 +53,21 @@
     "homepage": "https://github.com/0xProject/protocol/tree/main/contracts/extensions",
     "devDependencies": {
         "@0x/abi-gen": "^5.6.0",
-        "@0x/contract-addresses": "^6.3.0",
-        "@0x/contract-wrappers": "^13.17.0",
-        "@0x/contracts-broker": "^1.1.32",
-        "@0x/contracts-coordinator": "^3.1.33",
-        "@0x/contracts-dev-utils": "^1.3.31",
-        "@0x/contracts-exchange-forwarder": "^4.2.33",
-        "@0x/contracts-exchange-libs": "^4.3.32",
-        "@0x/contracts-extensions": "^6.2.27",
+        "@0x/contract-addresses": "^6.4.0",
+        "@0x/contract-wrappers": "^13.17.2",
+        "@0x/contracts-broker": "^1.1.34",
+        "@0x/contracts-coordinator": "^3.1.35",
+        "@0x/contracts-dev-utils": "^1.3.33",
+        "@0x/contracts-exchange-forwarder": "^4.2.35",
+        "@0x/contracts-exchange-libs": "^4.3.34",
+        "@0x/contracts-extensions": "^6.2.29",
         "@0x/contracts-gen": "^2.0.38",
-        "@0x/contracts-utils": "^4.7.11",
+        "@0x/contracts-utils": "^4.7.13",
         "@0x/coordinator-server": "^1.0.5",
         "@0x/dev-utils": "^4.2.7",
-        "@0x/migrations": "^8.0.9",
-        "@0x/order-utils": "^10.4.24",
-        "@0x/protocol-utils": "^1.7.0",
+        "@0x/migrations": "^8.0.11",
+        "@0x/order-utils": "^10.4.26",
+        "@0x/protocol-utils": "^1.7.2",
         "@0x/sol-compiler": "^4.7.3",
         "@0x/tslint-config": "^4.1.4",
         "@0x/web3-wrapper": "^7.5.3",
@@ -93,17 +93,17 @@
         "typescript": "4.2.2"
     },
     "dependencies": {
-        "@0x/asset-swapper": "^6.17.1",
+        "@0x/asset-swapper": "^6.18.2",
         "@0x/base-contract": "^6.4.0",
-        "@0x/contracts-asset-proxy": "^3.7.14",
-        "@0x/contracts-erc1155": "^2.1.32",
-        "@0x/contracts-erc20": "^3.3.11",
-        "@0x/contracts-erc721": "^3.1.32",
-        "@0x/contracts-exchange": "^3.2.33",
-        "@0x/contracts-multisig": "^4.1.33",
-        "@0x/contracts-staking": "^2.0.40",
-        "@0x/contracts-test-utils": "^5.4.3",
-        "@0x/contracts-zero-ex": "^0.25.0",
+        "@0x/contracts-asset-proxy": "^3.7.16",
+        "@0x/contracts-erc1155": "^2.1.34",
+        "@0x/contracts-erc20": "^3.3.13",
+        "@0x/contracts-erc721": "^3.1.34",
+        "@0x/contracts-exchange": "^3.2.35",
+        "@0x/contracts-multisig": "^4.1.35",
+        "@0x/contracts-staking": "^2.0.42",
+        "@0x/contracts-test-utils": "^5.4.5",
+        "@0x/contracts-zero-ex": "^0.26.0",
         "@0x/subproviders": "^6.5.3",
         "@0x/types": "^3.3.3",
         "@0x/typescript-typings": "^5.2.0",

contracts/multisig/CHANGELOG.json

@@ -1,4 +1,22 @@
 [
+    {
+        "timestamp": 1624356181,
+        "version": "4.1.35",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1623382456,
+        "version": "4.1.34",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
     {
         "timestamp": 1622609597,
         "version": "4.1.33",

contracts/multisig/CHANGELOG.md

@@ -5,6 +5,14 @@ Edit the package's CHANGELOG.json file only.
 
 CHANGELOG
 
+## v4.1.35 - _June 22, 2021_
+
+    * Dependencies updated
+
+## v4.1.34 - _June 11, 2021_
+
+    * Dependencies updated
+
 ## v4.1.33 - _June 2, 2021_
 
     * Dependencies updated

contracts/multisig/package.json

@@ -1,6 +1,6 @@
 {
     "name": "@0x/contracts-multisig",
-    "version": "4.1.33",
+    "version": "4.1.35",
     "engines": {
         "node": ">=6.12"
     },
@@ -50,11 +50,11 @@
     "homepage": "https://github.com/0xProject/protocol/tree/main/contracts/multisig",
     "devDependencies": {
         "@0x/abi-gen": "^5.6.0",
-        "@0x/contracts-asset-proxy": "^3.7.14",
-        "@0x/contracts-erc20": "^3.3.11",
+        "@0x/contracts-asset-proxy": "^3.7.16",
+        "@0x/contracts-erc20": "^3.3.13",
         "@0x/contracts-gen": "^2.0.38",
-        "@0x/contracts-test-utils": "^5.4.3",
-        "@0x/contracts-utils": "^4.7.11",
+        "@0x/contracts-test-utils": "^5.4.5",
+        "@0x/contracts-utils": "^4.7.13",
         "@0x/dev-utils": "^4.2.7",
         "@0x/sol-compiler": "^4.7.3",
         "@0x/tslint-config": "^4.1.4",

contracts/staking/CHANGELOG.json

@@ -1,4 +1,22 @@
 [
+    {
+        "timestamp": 1624356181,
+        "version": "2.0.42",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1623382456,
+        "version": "2.0.41",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
     {
         "timestamp": 1622609597,
         "version": "2.0.40",

contracts/staking/CHANGELOG.md

@@ -5,6 +5,14 @@ Edit the package's CHANGELOG.json file only.
 
 CHANGELOG
 
+## v2.0.42 - _June 22, 2021_
+
+    * Dependencies updated
+
+## v2.0.41 - _June 11, 2021_
+
+    * Dependencies updated
+
 ## v2.0.40 - _June 2, 2021_
 
     * Dependencies updated

contracts/staking/package.json

@@ -1,6 +1,6 @@
 {
     "name": "@0x/contracts-staking",
-    "version": "2.0.40",
+    "version": "2.0.42",
     "engines": {
         "node": ">=6.12"
     },
@@ -54,14 +54,14 @@
     "homepage": "https://github.com/0xProject/protocol/tree/main/contracts/tokens",
     "devDependencies": {
         "@0x/abi-gen": "^5.6.0",
-        "@0x/contracts-asset-proxy": "^3.7.14",
-        "@0x/contracts-dev-utils": "^1.3.31",
-        "@0x/contracts-erc20": "^3.3.11",
-        "@0x/contracts-exchange-libs": "^4.3.32",
+        "@0x/contracts-asset-proxy": "^3.7.16",
+        "@0x/contracts-dev-utils": "^1.3.33",
+        "@0x/contracts-erc20": "^3.3.13",
+        "@0x/contracts-exchange-libs": "^4.3.34",
         "@0x/contracts-gen": "^2.0.38",
-        "@0x/contracts-utils": "^4.7.11",
+        "@0x/contracts-utils": "^4.7.13",
         "@0x/dev-utils": "^4.2.7",
-        "@0x/order-utils": "^10.4.24",
+        "@0x/order-utils": "^10.4.26",
         "@0x/sol-compiler": "^4.7.3",
         "@0x/ts-doc-gen": "^0.0.28",
         "@0x/tslint-config": "^4.1.4",
@@ -88,7 +88,7 @@
     },
     "dependencies": {
         "@0x/base-contract": "^6.4.0",
-        "@0x/contracts-test-utils": "^5.4.3",
+        "@0x/contracts-test-utils": "^5.4.5",
         "@0x/typescript-typings": "^5.2.0",
         "@0x/utils": "^6.4.3",
         "ethereum-types": "^3.5.0",

contracts/test-utils/CHANGELOG.json

@@ -1,4 +1,22 @@
 [
+    {
+        "timestamp": 1624356181,
+        "version": "5.4.5",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1623382456,
+        "version": "5.4.4",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
     {
         "timestamp": 1622609597,
         "version": "5.4.3",

contracts/test-utils/CHANGELOG.md

@@ -5,6 +5,14 @@ Edit the package's CHANGELOG.json file only.
 
 CHANGELOG
 
+## v5.4.5 - _June 22, 2021_
+
+    * Dependencies updated
+
+## v5.4.4 - _June 11, 2021_
+
+    * Dependencies updated
+
 ## v5.4.3 - _June 2, 2021_
 
     * Dependencies updated

contracts/test-utils/package.json

@@ -1,6 +1,6 @@
 {
     "name": "@0x/contracts-test-utils",
-    "version": "5.4.3",
+    "version": "5.4.5",
     "engines": {
         "node": ">=6.12"
     },
@@ -44,10 +44,10 @@
     "dependencies": {
         "@0x/assert": "^3.0.27",
         "@0x/base-contract": "^6.4.0",
-        "@0x/contract-addresses": "^6.3.0",
+        "@0x/contract-addresses": "^6.4.0",
         "@0x/dev-utils": "^4.2.7",
         "@0x/json-schemas": "^6.1.3",
-        "@0x/order-utils": "^10.4.24",
+        "@0x/order-utils": "^10.4.26",
         "@0x/sol-coverage": "^4.0.37",
         "@0x/sol-profiler": "^4.1.27",
         "@0x/sol-trace": "^3.0.37",

contracts/treasury/CHANGELOG.json

@@ -1,4 +1,22 @@
 [
+    {
+        "timestamp": 1624356181,
+        "version": "1.2.3",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1623382456,
+        "version": "1.2.2",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
     {
         "timestamp": 1622609597,
         "version": "1.2.1",

contracts/treasury/CHANGELOG.md

@@ -5,6 +5,14 @@ Edit the package's CHANGELOG.json file only.
 
 CHANGELOG
 
+## v1.2.3 - _June 22, 2021_
+
+    * Dependencies updated
+
+## v1.2.2 - _June 11, 2021_
+
+    * Dependencies updated
+
 ## v1.2.1 - _June 2, 2021_
 
     * Dependencies updated

contracts/treasury/package.json

@@ -1,6 +1,6 @@
 {
     "name": "@0x/contracts-treasury",
-    "version": "1.2.1",
+    "version": "1.2.3",
     "engines": {
         "node": ">=6.12"
     },
@@ -47,12 +47,12 @@
     "homepage": "https://github.com/0xProject/protocol/tree/main/contracts/treasury",
     "devDependencies": {
         "@0x/abi-gen": "^5.6.0",
-        "@0x/contract-addresses": "^6.3.0",
-        "@0x/contracts-asset-proxy": "^3.7.14",
-        "@0x/contracts-erc20": "^3.3.11",
+        "@0x/contract-addresses": "^6.4.0",
+        "@0x/contracts-asset-proxy": "^3.7.16",
+        "@0x/contracts-erc20": "^3.3.13",
         "@0x/contracts-gen": "^2.0.38",
-        "@0x/contracts-staking": "^2.0.40",
-        "@0x/contracts-test-utils": "^5.4.3",
+        "@0x/contracts-staking": "^2.0.42",
+        "@0x/contracts-test-utils": "^5.4.5",
         "@0x/sol-compiler": "^4.7.3",
         "@0x/ts-doc-gen": "^0.0.28",
         "@0x/tslint-config": "^4.1.4",
@@ -73,7 +73,7 @@
     },
     "dependencies": {
         "@0x/base-contract": "^6.4.0",
-        "@0x/protocol-utils": "^1.7.0",
+        "@0x/protocol-utils": "^1.7.2",
         "@0x/subproviders": "^6.5.3",
         "@0x/types": "^3.3.3",
         "@0x/typescript-typings": "^5.2.0",

contracts/utils/CHANGELOG.json

@@ -1,4 +1,22 @@
 [
+    {
+        "timestamp": 1624356181,
+        "version": "4.7.13",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "timestamp": 1623382456,
+        "version": "4.7.12",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
     {
         "timestamp": 1622609597,
         "version": "4.7.11",

contracts/utils/CHANGELOG.md

@@ -5,6 +5,14 @@ Edit the package's CHANGELOG.json file only.
 
 CHANGELOG
 
+## v4.7.13 - _June 22, 2021_
+
+    * Dependencies updated
+
+## v4.7.12 - _June 11, 2021_
+
+    * Dependencies updated
+
 ## v4.7.11 - _June 2, 2021_
 
     * Dependencies updated

contracts/utils/package.json

@@ -1,6 +1,6 @@
 {
     "name": "@0x/contracts-utils",
-    "version": "4.7.11",
+    "version": "4.7.13",
     "engines": {
         "node": ">=6.12"
     },
@@ -52,9 +52,9 @@
     "devDependencies": {
         "@0x/abi-gen": "^5.6.0",
         "@0x/contracts-gen": "^2.0.38",
-        "@0x/contracts-test-utils": "^5.4.3",
+        "@0x/contracts-test-utils": "^5.4.5",
         "@0x/dev-utils": "^4.2.7",
-        "@0x/order-utils": "^10.4.24",
+        "@0x/order-utils": "^10.4.26",
         "@0x/sol-compiler": "^4.7.3",
         "@0x/tslint-config": "^4.1.4",
         "@0x/types": "^3.3.3",

contracts/zero-ex/CHANGELOG.json

@@ -1,4 +1,32 @@
 [
+    {
+        "version": "0.27.0",
+        "changes": [
+            {
+                "note": "Refactor Mixins which use WETH to also have an Internal variant, allowing WETH to be passed in for SwapRevertSampler",
+                "pr": 245
+            }
+        ]
+    },
+    {
+        "version": "0.26.0",
+        "changes": [
+            {
+                "note": "Add Lido stETH deposit integration",
+                "pr": 260
+            }
+        ],
+        "timestamp": 1624356181
+    },
+    {
+        "timestamp": 1623382456,
+        "version": "0.25.1",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
     {
         "version": "0.25.0",
         "changes": [

contracts/zero-ex/CHANGELOG.md

@@ -5,6 +5,14 @@ Edit the package's CHANGELOG.json file only.
 
 CHANGELOG
 
+## v0.26.0 - _June 22, 2021_
+
+    * Add Lido stETH deposit integration (#260)
+
+## v0.25.1 - _June 11, 2021_
+
+    * Dependencies updated
+
 ## v0.25.0 - _June 2, 2021_
 
     * Add OtcOrdersFeature (#244)

contracts/zero-ex/contracts/src/transformers/bridges/BridgeAdapter.sol

@@ -27,11 +27,13 @@ import "./mixins/MixinBalancerV2.sol";
 import "./mixins/MixinBancor.sol";
 import "./mixins/MixinCoFiX.sol";
 import "./mixins/MixinCurve.sol";
+import "./mixins/MixinCurveV2.sol";
 import "./mixins/MixinCryptoCom.sol";
 import "./mixins/MixinDodo.sol";
 import "./mixins/MixinDodoV2.sol";
 import "./mixins/MixinKyber.sol";
 import "./mixins/MixinKyberDmm.sol";
+import "./mixins/MixinLido.sol";
 import "./mixins/MixinMakerPSM.sol";
 import "./mixins/MixinMooniswap.sol";
 import "./mixins/MixinMStable.sol";
@@ -50,11 +52,13 @@ contract BridgeAdapter is
     MixinBancor,
     MixinCoFiX,
     MixinCurve,
+    MixinCurveV2,
     MixinCryptoCom,
     MixinDodo,
     MixinDodoV2,
     MixinKyber,
     MixinKyberDmm,
+    MixinLido,
     MixinMakerPSM,
     MixinMooniswap,
     MixinMStable,
@@ -73,10 +77,12 @@ contract BridgeAdapter is
         MixinBancor(weth)
         MixinCoFiX()
         MixinCurve(weth)
+        MixinCurveV2()
         MixinCryptoCom()
         MixinDodo()
         MixinDodoV2()
         MixinKyber(weth)
+        MixinLido(weth)
         MixinMakerPSM()
         MixinMooniswap(weth)
         MixinMStable()
@@ -107,6 +113,13 @@ contract BridgeAdapter is
                 sellAmount,
                 order.bridgeData
             );
+        } else if (protocolId == BridgeProtocols.CURVEV2) {
+            boughtAmount = _tradeCurveV2(
+                sellToken,
+                buyToken,
+                sellAmount,
+                order.bridgeData
+            );
         } else if (protocolId == BridgeProtocols.UNISWAPV3) {
             boughtAmount = _tradeUniswapV3(
                 sellToken,
@@ -225,6 +238,13 @@ contract BridgeAdapter is
                 sellAmount,
                 order.bridgeData
             );
+        } else if (protocolId == BridgeProtocols.LIDO) {
+            boughtAmount = _tradeLido(
+                sellToken,
+                buyToken,
+                sellAmount,
+                order.bridgeData
+            );
         } else {
             boughtAmount = _tradeZeroExBridge(
                 sellToken,

contracts/zero-ex/contracts/src/transformers/bridges/BridgeProtocols.sol

@@ -47,4 +47,6 @@ library BridgeProtocols {
     uint128 internal constant BALANCERV2  = 17;
     uint128 internal constant UNISWAPV3   = 18;
     uint128 internal constant KYBERDMM    = 19;
+    uint128 internal constant CURVEV2     = 20;
+    uint128 internal constant LIDO        = 21;
 }

contracts/zero-ex/contracts/src/transformers/bridges/mixins/MixinBancor.sol

@@ -39,6 +39,13 @@ interface IBancorNetwork {
         external
         payable
         returns (uint256);
+    function conversionPath(address _sourceToken, address _targetToken) external view returns (address[] memory);
+    function rateByPath(address[] memory _path, uint256 _amount) external view returns (uint256);
+}
+
+interface IBancorRegistry {
+    function getAddress(bytes32 _contractName) external view returns (address);
+    function BANCOR_NETWORK() external view returns (bytes32);
 }
 
 
@@ -62,6 +69,18 @@ contract MixinBancor {
     )
         internal
         returns (uint256 boughtAmount)
+    {
+        return _tradeBancorInternal(WETH, buyToken, sellAmount, bridgeData);
+    }
+
+    function _tradeBancorInternal(
+        IEtherTokenV06 weth,
+        IERC20TokenV06 buyToken,
+        uint256 sellAmount,
+        bytes memory bridgeData
+    )
+        internal
+        returns (uint256 boughtAmount)
     {
         // Decode the bridge data.
         IBancorNetwork bancorNetworkAddress;
@@ -79,7 +98,7 @@ contract MixinBancor {
         require(path.length >= 2, "MixinBancor/PATH_LENGTH_MUST_BE_AT_LEAST_TWO");
         require(
             path[path.length - 1] == buyToken ||
-            (path[path.length - 1] == BANCOR_ETH_ADDRESS && buyToken == WETH),
+            (path[path.length - 1] == BANCOR_ETH_ADDRESS && buyToken == weth),
             "MixinBancor/LAST_ELEMENT_OF_PATH_MUST_MATCH_OUTPUT_TOKEN"
         );
 
@@ -88,7 +107,7 @@ contract MixinBancor {
         // The Bancor path will have ETH as the 0xeee address
         // Bancor expects to be paid in ETH not WETH
         if (path[0] == BANCOR_ETH_ADDRESS) {
-            WETH.withdraw(sellAmount);
+            weth.withdraw(sellAmount);
             payableAmount = sellAmount;
         } else {
             // Grant an allowance to the Bancor Network.
@@ -109,7 +128,7 @@ contract MixinBancor {
             0 // affiliateFee; no fee paid
         );
         if (path[path.length - 1] == BANCOR_ETH_ADDRESS) {
-            WETH.deposit{value: boughtAmount}();
+            weth.deposit{value: boughtAmount}();
         }
 
         return boughtAmount;

contracts/zero-ex/contracts/src/transformers/bridges/mixins/MixinCurve.sol

@@ -57,13 +57,26 @@ contract MixinCurve {
     )
         internal
         returns (uint256 boughtAmount)
+    {
+        return _tradeCurveInternal(WETH, sellToken, buyToken, sellAmount, bridgeData);
+    }
+
+    function _tradeCurveInternal(
+        IEtherTokenV06 weth,
+        IERC20TokenV06 sellToken,
+        IERC20TokenV06 buyToken,
+        uint256 sellAmount,
+        bytes memory bridgeData
+    )
+        internal
+        returns (uint256 boughtAmount)
     {
         // Decode the bridge data to get the Curve metadata.
         CurveBridgeData memory data = abi.decode(bridgeData, (CurveBridgeData));
         uint256 payableAmount;
-        if (sellToken == WETH) {
+        if (sellToken == weth) {
             payableAmount = sellAmount;
-            WETH.withdraw(sellAmount);
+            weth.withdraw(sellAmount);
         } else {
             sellToken.approveIfBelow(data.curveAddress, sellAmount);
         }
@@ -83,9 +96,9 @@ contract MixinCurve {
             resultData.rrevert();
         }
 
-        if (buyToken == WETH) {
+        if (buyToken == weth) {
             boughtAmount = address(this).balance;
-            WETH.deposit{ value: boughtAmount }();
+            weth.deposit{ value: boughtAmount }();
         }
 
         return buyToken.balanceOf(address(this)).safeSub(beforeBalance);

contracts/zero-ex/contracts/src/transformers/bridges/mixins/MixinCurveV2.sol

@@ -0,0 +1,71 @@
+// SPDX-License-Identifier: Apache-2.0
+/*
+
+  Copyright 2021 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.6.5;
+pragma experimental ABIEncoderV2;
+
+import "@0x/contracts-utils/contracts/src/v06/errors/LibRichErrorsV06.sol";
+import "@0x/contracts-erc20/contracts/src/v06/LibERC20TokenV06.sol";
+import "@0x/contracts-erc20/contracts/src/v06/IERC20TokenV06.sol";
+import "@0x/contracts-utils/contracts/src/v06/LibSafeMathV06.sol";
+
+contract MixinCurveV2 {
+
+    using LibERC20TokenV06 for IERC20TokenV06;
+    using LibSafeMathV06 for uint256;
+    using LibRichErrorsV06 for bytes;
+
+    struct CurveBridgeDataV2 {
+        address curveAddress;
+        bytes4 exchangeFunctionSelector;
+        int128 fromCoinIdx;
+        int128 toCoinIdx;
+    }
+
+    function _tradeCurveV2(
+        IERC20TokenV06 sellToken,
+        IERC20TokenV06 buyToken,
+        uint256 sellAmount,
+        bytes memory bridgeData
+    )
+        internal
+        returns (uint256 boughtAmount)
+    {
+        // Decode the bridge data to get the Curve metadata.
+        CurveBridgeDataV2 memory data = abi.decode(bridgeData, (CurveBridgeDataV2));
+        sellToken.approveIfBelow(data.curveAddress, sellAmount);
+
+        uint256 beforeBalance = buyToken.balanceOf(address(this));
+        (bool success, bytes memory resultData) =
+            data.curveAddress.call(abi.encodeWithSelector(
+                data.exchangeFunctionSelector,
+                data.fromCoinIdx,
+                data.toCoinIdx,
+                // dx
+                sellAmount,
+                // min dy
+                1
+            ));
+        if (!success) {
+            resultData.rrevert();
+        }
+
+        return buyToken.balanceOf(address(this)).safeSub(beforeBalance);
+    }
+}

contracts/zero-ex/contracts/src/transformers/bridges/mixins/MixinKyber.sol

@@ -52,6 +52,7 @@ interface IKyberNetworkProxy {
         external
         payable
         returns (uint256 boughtAmount);
+
 }
 
 contract MixinKyber {
@@ -78,12 +79,26 @@ contract MixinKyber {
     )
         internal
         returns (uint256 boughtAmount)
+    {
+        return _tradeKyberInternal(KYBER_ETH_ADDRESS, WETH, sellToken, buyToken, sellAmount, bridgeData);
+    }
+
+    function _tradeKyberInternal(
+        IERC20TokenV06 kyberEthAddress,
+        IEtherTokenV06 weth,
+        IERC20TokenV06 sellToken,
+        IERC20TokenV06 buyToken,
+        uint256 sellAmount,
+        bytes memory bridgeData
+    )
+        internal
+        returns (uint256 boughtAmount)
     {
         (IKyberNetworkProxy kyber, bytes memory hint) =
             abi.decode(bridgeData, (IKyberNetworkProxy, bytes));
 
         uint256 payableAmount = 0;
-        if (sellToken != WETH) {
+        if (sellToken != weth) {
             // If the input token is not WETH, grant an allowance to the exchange
             // to spend them.
             sellToken.approveIfBelow(
@@ -93,18 +108,18 @@ contract MixinKyber {
         } else {
             // If the input token is WETH, unwrap it and attach it to the call.
             payableAmount = sellAmount;
-            WETH.withdraw(payableAmount);
+            weth.withdraw(payableAmount);
         }
 
         // Try to sell all of this contract's input token balance through
         // `KyberNetworkProxy.trade()`.
         boughtAmount = kyber.tradeWithHint{ value: payableAmount }(
             // Input token.
-            sellToken == WETH ? KYBER_ETH_ADDRESS : sellToken,
+            sellToken == weth ? kyberEthAddress : sellToken,
             // Sell amount.
             sellAmount,
             // Output token.
-            buyToken == WETH ? KYBER_ETH_ADDRESS : buyToken,
+            buyToken == weth ? kyberEthAddress : buyToken,
             // Transfer to this contract
             address(uint160(address(this))),
             // Buy as much as possible.
@@ -116,8 +131,8 @@ contract MixinKyber {
             hint
         );
         // If receving ETH, wrap it to WETH.
-        if (buyToken == WETH) {
-            WETH.deposit{ value: boughtAmount }();
+        if (buyToken == weth) {
+            weth.deposit{ value: boughtAmount }();
         }
         return boughtAmount;
     }

contracts/zero-ex/contracts/src/transformers/bridges/mixins/MixinKyberDmm.sol

@@ -30,6 +30,8 @@ import "../IBridgeAdapter.sol";
 */
 interface IKyberDmmRouter {
 
+    function factory() external view returns (address);
+
     /// @dev Swaps an exact amount of input tokens for as many output tokens as possible, along the route determined by the path.
     ///      The first element of path is the input token, the last is the output token, and any intermediate elements represent
     ///      intermediate pairs to trade through (if, for example, a direct pair does not exist).

contracts/zero-ex/contracts/src/transformers/bridges/mixins/MixinLido.sol

@@ -0,0 +1,83 @@
+// SPDX-License-Identifier: Apache-2.0
+/*
+
+  Copyright 2021 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.6.5;
+pragma experimental ABIEncoderV2;
+
+import "@0x/contracts-erc20/contracts/src/v06/LibERC20TokenV06.sol";
+import "@0x/contracts-erc20/contracts/src/v06/IERC20TokenV06.sol";
+import "@0x/contracts-erc20/contracts/src/v06/IEtherTokenV06.sol";
+
+
+/// @dev Minimal interface for minting StETH
+interface ILido {
+    /// @dev Adds eth to the pool
+    /// @param _referral optional address for referrals
+    /// @return StETH Amount of shares generated
+    function submit(address _referral) external payable returns (uint256 StETH);
+    /// @dev Retrieve the current pooled ETH representation of the shares amount
+    /// @param _sharesAmount amount of shares
+    /// @return amount of pooled ETH represented by the shares amount
+    function getPooledEthByShares(uint256 _sharesAmount) external view returns (uint256);
+}
+
+
+contract MixinLido {
+    using LibERC20TokenV06 for IERC20TokenV06;
+    using LibERC20TokenV06 for IEtherTokenV06;
+
+    IEtherTokenV06 private immutable WETH;
+
+    constructor(IEtherTokenV06 weth)
+        public
+    {
+        WETH = weth;
+    }
+
+    function _tradeLido(
+        IERC20TokenV06 sellToken,
+        IERC20TokenV06 buyToken,
+        uint256 sellAmount,
+        bytes memory bridgeData
+    )
+        internal
+        returns (uint256 boughtAmount)
+    {
+        return _tradeLidoInternal(WETH, sellToken, buyToken, sellAmount, bridgeData);
+    }
+
+    function _tradeLidoInternal(
+        IEtherTokenV06 weth,
+        IERC20TokenV06 sellToken,
+        IERC20TokenV06 buyToken,
+        uint256 sellAmount,
+        bytes memory bridgeData
+    )
+        internal
+        returns (uint256 boughtAmount)
+    {
+        (ILido lido) = abi.decode(bridgeData, (ILido));
+        if (address(sellToken) == address(weth) && address(buyToken) == address(lido)) {
+            weth.withdraw(sellAmount);
+            boughtAmount = lido.getPooledEthByShares(lido.submit{ value: sellAmount}(address(0)));
+        } else {
+            revert("MixinLido/UNSUPPORTED_TOKEN_PAIR");
+        }
+    }
+}

contracts/zero-ex/contracts/src/transformers/bridges/mixins/MixinMooniswap.sol

@@ -66,12 +66,26 @@ contract MixinMooniswap {
         internal
         returns (uint256 boughtAmount)
     {
+
+        return _tradeMooniswapInternal(WETH, sellToken, buyToken, sellAmount, bridgeData);
+    }
+
+    function _tradeMooniswapInternal(
+        IEtherTokenV06 weth,
+        IERC20TokenV06 sellToken,
+        IERC20TokenV06 buyToken,
+        uint256 sellAmount,
+        bytes memory bridgeData
+    )
+        internal
+        returns (uint256 boughtAmount)
+    {
         (IMooniswapPool pool) = abi.decode(bridgeData, (IMooniswapPool));
 
         // Convert WETH to ETH.
         uint256 ethValue = 0;
-        if (sellToken == WETH) {
-            WETH.withdraw(sellAmount);
+        if (sellToken == weth) {
+            weth.withdraw(sellAmount);
             ethValue = sellAmount;
         } else {
             // Grant the pool an allowance.
@@ -82,16 +96,16 @@ contract MixinMooniswap {
         }
 
         boughtAmount = pool.swap{value: ethValue}(
-            sellToken == WETH ? IERC20TokenV06(0) : sellToken,
-            buyToken == WETH ? IERC20TokenV06(0) : buyToken,
+            sellToken == weth ? IERC20TokenV06(0) : sellToken,
+            buyToken == weth ? IERC20TokenV06(0) : buyToken,
             sellAmount,
             1,
             address(0)
         );
 
         // Wrap ETH to WETH.
-        if (buyToken == WETH) {
-            WETH.deposit{value:boughtAmount}();
+        if (buyToken == weth) {
+            weth.deposit{value:boughtAmount}();
         }
     }
 }

contracts/zero-ex/contracts/src/transformers/bridges/mixins/MixinUniswap.sol

@@ -124,21 +124,35 @@ contract MixinUniswap {
     )
         internal
         returns (uint256 boughtAmount)
+    {
+        return _tradeUniswapInternal(WETH, sellToken, buyToken, sellAmount, bridgeData);
+    }
+
+    function _tradeUniswapInternal(
+        IEtherTokenV06 weth,
+        IERC20TokenV06 sellToken,
+        IERC20TokenV06 buyToken,
+        uint256 sellAmount,
+        bytes memory bridgeData
+    )
+        internal
+        returns (uint256 boughtAmount)
     {
         IUniswapExchangeFactory exchangeFactory =
             abi.decode(bridgeData, (IUniswapExchangeFactory));
 
         // Get the exchange for the token pair.
         IUniswapExchange exchange = _getUniswapExchangeForTokenPair(
+            weth,
             exchangeFactory,
             sellToken,
             buyToken
         );
 
         // Convert from WETH to a token.
-        if (sellToken == WETH) {
+        if (sellToken == weth) {
             // Unwrap the WETH.
-            WETH.withdraw(sellAmount);
+            weth.withdraw(sellAmount);
             // Buy as much of `buyToken` token with ETH as possible
             boughtAmount = exchange.ethToTokenTransferInput{ value: sellAmount }(
                 // Minimum buy amount.
@@ -150,7 +164,7 @@ contract MixinUniswap {
             );
 
         // Convert from a token to WETH.
-        } else if (buyToken == WETH) {
+        } else if (buyToken == weth) {
             // Grant the exchange an allowance.
             sellToken.approveIfBelow(
                 address(exchange),
@@ -166,7 +180,7 @@ contract MixinUniswap {
                 block.timestamp
             );
             // Wrap the ETH.
-            WETH.deposit{ value: boughtAmount }();
+            weth.deposit{ value: boughtAmount }();
         // Convert from one token to another.
         } else {
             // Grant the exchange an allowance.
@@ -200,6 +214,7 @@ contract MixinUniswap {
     /// @param buyToken The address of the token we are converting to.
     /// @return exchange The uniswap exchange.
     function _getUniswapExchangeForTokenPair(
+        IEtherTokenV06 weth,
         IUniswapExchangeFactory exchangeFactory,
         IERC20TokenV06 sellToken,
         IERC20TokenV06 buyToken
@@ -209,7 +224,7 @@ contract MixinUniswap {
         returns (IUniswapExchange exchange)
     {
         // Whichever isn't WETH is the exchange token.
-        exchange = sellToken == WETH
+        exchange = sellToken == weth
             ? exchangeFactory.getExchange(buyToken)
             : exchangeFactory.getExchange(sellToken);
         require(address(exchange) != address(0), "MixinUniswap/NO_EXCHANGE");

contracts/zero-ex/package.json

@@ -1,6 +1,6 @@
 {
     "name": "@0x/contracts-zero-ex",
-    "version": "0.25.0",
+    "version": "0.26.0",
     "engines": {
         "node": ">=6.12"
     },
@@ -43,7 +43,7 @@
     "config": {
         "publicInterfaceContracts": "IZeroEx,ZeroEx,FullMigration,InitialMigration,IFlashWallet,IERC20Transformer,IOwnableFeature,ISimpleFunctionRegistryFeature,ITransformERC20Feature,FillQuoteTransformer,PayTakerTransformer,PositiveSlippageFeeTransformer,WethTransformer,OwnableFeature,SimpleFunctionRegistryFeature,TransformERC20Feature,AffiliateFeeTransformer,MetaTransactionsFeature,LogMetadataTransformer,BridgeAdapter,LiquidityProviderFeature,ILiquidityProviderFeature,NativeOrdersFeature,INativeOrdersFeature,FeeCollectorController,FeeCollector,CurveLiquidityProvider,BatchFillNativeOrdersFeature,IBatchFillNativeOrdersFeature,MultiplexFeature,IMultiplexFeature,OtcOrdersFeature,IOtcOrdersFeature",
         "abis:comment": "This list is auto-generated by contracts-gen. Don't edit manually.",
-        "abis": "./test/generated-artifacts/@(AffiliateFeeTransformer|BatchFillNativeOrdersFeature|BootstrapFeature|BridgeAdapter|BridgeProtocols|CurveLiquidityProvider|FeeCollector|FeeCollectorController|FillQuoteTransformer|FixinCommon|FixinEIP712|FixinProtocolFees|FixinReentrancyGuard|FixinTokenSpender|FlashWallet|FullMigration|IBatchFillNativeOrdersFeature|IBootstrapFeature|IBridgeAdapter|IERC20Bridge|IERC20Transformer|IFeature|IFlashWallet|ILiquidityProvider|ILiquidityProviderFeature|ILiquidityProviderSandbox|IMetaTransactionsFeature|IMooniswapPool|IMultiplexFeature|INativeOrdersEvents|INativeOrdersFeature|IOtcOrdersFeature|IOwnableFeature|IPancakeSwapFeature|ISimpleFunctionRegistryFeature|IStaking|ITestSimpleFunctionRegistryFeature|ITokenSpenderFeature|ITransformERC20Feature|IUniswapFeature|IUniswapV2Pair|IUniswapV3Feature|IUniswapV3Pool|IZeroEx|InitialMigration|LibBootstrap|LibCommonRichErrors|LibERC20Transformer|LibFeeCollector|LibLiquidityProviderRichErrors|LibMetaTransactionsRichErrors|LibMetaTransactionsStorage|LibMigrate|LibNativeOrder|LibNativeOrdersRichErrors|LibNativeOrdersStorage|LibOtcOrdersStorage|LibOwnableRichErrors|LibOwnableStorage|LibProxyRichErrors|LibProxyStorage|LibReentrancyGuardStorage|LibSignature|LibSignatureRichErrors|LibSimpleFunctionRegistryRichErrors|LibSimpleFunctionRegistryStorage|LibStorage|LibTransformERC20RichErrors|LibTransformERC20Storage|LibWalletRichErrors|LiquidityProviderFeature|LiquidityProviderSandbox|LogMetadataTransformer|MetaTransactionsFeature|MixinBalancer|MixinBalancerV2|MixinBancor|MixinCoFiX|MixinCryptoCom|MixinCurve|MixinDodo|MixinDodoV2|MixinKyber|MixinKyberDmm|MixinMStable|MixinMakerPSM|MixinMooniswap|MixinNerve|MixinOasis|MixinShell|MixinUniswap|MixinUniswapV2|MixinUniswapV3|MixinZeroExBridge|MooniswapLiquidityProvider|MultiplexFeature|NativeOrdersCancellation|NativeOrdersFeature|NativeOrdersInfo|NativeOrdersProtocolFees|NativeOrdersSettlement|OtcOrdersFeature|OwnableFeature|PancakeSwapFeature|PayTakerTransformer|PermissionlessTransformerDeployer|PositiveSlippageFeeTransformer|SimpleFunctionRegistryFeature|TestBridge|TestCallTarget|TestCurve|TestDelegateCaller|TestFeeCollectorController|TestFillQuoteTransformerBridge|TestFillQuoteTransformerExchange|TestFillQuoteTransformerHost|TestFixinProtocolFees|TestFixinTokenSpender|TestFullMigration|TestInitialMigration|TestLibNativeOrder|TestLibSignature|TestLiquidityProvider|TestMetaTransactionsNativeOrdersFeature|TestMetaTransactionsTransformERC20Feature|TestMigrator|TestMintTokenERC20Transformer|TestMintableERC20Token|TestMooniswap|TestNativeOrdersFeature|TestNoEthRecipient|TestOrderSignerRegistryWithContractWallet|TestPermissionlessTransformerDeployerSuicidal|TestPermissionlessTransformerDeployerTransformer|TestRfqOriginRegistration|TestSimpleFunctionRegistryFeatureImpl1|TestSimpleFunctionRegistryFeatureImpl2|TestStaking|TestTokenSpenderERC20Token|TestTransformERC20|TestTransformerBase|TestTransformerDeployerTransformer|TestTransformerHost|TestUniswapV3Factory|TestUniswapV3Feature|TestUniswapV3Pool|TestWeth|TestWethTransformerHost|TestZeroExFeature|TransformERC20Feature|Transformer|TransformerDeployer|UniswapFeature|UniswapV3Feature|WethTransformer|ZeroEx|ZeroExOptimized).json"
+        "abis": "./test/generated-artifacts/@(AffiliateFeeTransformer|BatchFillNativeOrdersFeature|BootstrapFeature|BridgeAdapter|BridgeProtocols|CurveLiquidityProvider|FeeCollector|FeeCollectorController|FillQuoteTransformer|FixinCommon|FixinEIP712|FixinProtocolFees|FixinReentrancyGuard|FixinTokenSpender|FlashWallet|FullMigration|IBatchFillNativeOrdersFeature|IBootstrapFeature|IBridgeAdapter|IERC20Bridge|IERC20Transformer|IFeature|IFlashWallet|ILiquidityProvider|ILiquidityProviderFeature|ILiquidityProviderSandbox|IMetaTransactionsFeature|IMooniswapPool|IMultiplexFeature|INativeOrdersEvents|INativeOrdersFeature|IOtcOrdersFeature|IOwnableFeature|IPancakeSwapFeature|ISimpleFunctionRegistryFeature|IStaking|ITestSimpleFunctionRegistryFeature|ITokenSpenderFeature|ITransformERC20Feature|IUniswapFeature|IUniswapV2Pair|IUniswapV3Feature|IUniswapV3Pool|IZeroEx|InitialMigration|LibBootstrap|LibCommonRichErrors|LibERC20Transformer|LibFeeCollector|LibLiquidityProviderRichErrors|LibMetaTransactionsRichErrors|LibMetaTransactionsStorage|LibMigrate|LibNativeOrder|LibNativeOrdersRichErrors|LibNativeOrdersStorage|LibOtcOrdersStorage|LibOwnableRichErrors|LibOwnableStorage|LibProxyRichErrors|LibProxyStorage|LibReentrancyGuardStorage|LibSignature|LibSignatureRichErrors|LibSimpleFunctionRegistryRichErrors|LibSimpleFunctionRegistryStorage|LibStorage|LibTransformERC20RichErrors|LibTransformERC20Storage|LibWalletRichErrors|LiquidityProviderFeature|LiquidityProviderSandbox|LogMetadataTransformer|MetaTransactionsFeature|MixinBalancer|MixinBalancerV2|MixinBancor|MixinCoFiX|MixinCryptoCom|MixinCurve|MixinCurveV2|MixinDodo|MixinDodoV2|MixinKyber|MixinKyberDmm|MixinLido|MixinMStable|MixinMakerPSM|MixinMooniswap|MixinNerve|MixinOasis|MixinShell|MixinUniswap|MixinUniswapV2|MixinUniswapV3|MixinZeroExBridge|MooniswapLiquidityProvider|MultiplexFeature|NativeOrdersCancellation|NativeOrdersFeature|NativeOrdersInfo|NativeOrdersProtocolFees|NativeOrdersSettlement|OtcOrdersFeature|OwnableFeature|PancakeSwapFeature|PayTakerTransformer|PermissionlessTransformerDeployer|PositiveSlippageFeeTransformer|SimpleFunctionRegistryFeature|TestBridge|TestCallTarget|TestCurve|TestDelegateCaller|TestFeeCollectorController|TestFillQuoteTransformerBridge|TestFillQuoteTransformerExchange|TestFillQuoteTransformerHost|TestFixinProtocolFees|TestFixinTokenSpender|TestFullMigration|TestInitialMigration|TestLibNativeOrder|TestLibSignature|TestLiquidityProvider|TestMetaTransactionsNativeOrdersFeature|TestMetaTransactionsTransformERC20Feature|TestMigrator|TestMintTokenERC20Transformer|TestMintableERC20Token|TestMooniswap|TestNativeOrdersFeature|TestNoEthRecipient|TestOrderSignerRegistryWithContractWallet|TestPermissionlessTransformerDeployerSuicidal|TestPermissionlessTransformerDeployerTransformer|TestRfqOriginRegistration|TestSimpleFunctionRegistryFeatureImpl1|TestSimpleFunctionRegistryFeatureImpl2|TestStaking|TestTokenSpenderERC20Token|TestTransformERC20|TestTransformerBase|TestTransformerDeployerTransformer|TestTransformerHost|TestUniswapV3Factory|TestUniswapV3Feature|TestUniswapV3Pool|TestWeth|TestWethTransformerHost|TestZeroExFeature|TransformERC20Feature|Transformer|TransformerDeployer|UniswapFeature|UniswapV3Feature|WethTransformer|ZeroEx|ZeroExOptimized).json"
     },
     "repository": {
         "type": "git",
@@ -56,12 +56,12 @@
     "homepage": "https://github.com/0xProject/protocol/tree/main/contracts/zero-ex",
     "devDependencies": {
         "@0x/abi-gen": "^5.6.0",
-        "@0x/contract-addresses": "^6.3.0",
-        "@0x/contracts-erc20": "^3.3.11",
+        "@0x/contract-addresses": "^6.4.0",
+        "@0x/contracts-erc20": "^3.3.13",
         "@0x/contracts-gen": "^2.0.38",
-        "@0x/contracts-test-utils": "^5.4.3",
+        "@0x/contracts-test-utils": "^5.4.5",
         "@0x/dev-utils": "^4.2.7",
-        "@0x/order-utils": "^10.4.24",
+        "@0x/order-utils": "^10.4.26",
         "@0x/sol-compiler": "^4.7.3",
         "@0x/ts-doc-gen": "^0.0.28",
         "@0x/tslint-config": "^4.1.4",
@@ -83,7 +83,7 @@
     },
     "dependencies": {
         "@0x/base-contract": "^6.4.0",
-        "@0x/protocol-utils": "^1.7.0",
+        "@0x/protocol-utils": "^1.7.2",
         "@0x/subproviders": "^6.5.3",
         "@0x/types": "^3.3.3",
         "@0x/typescript-typings": "^5.2.0",

contracts/zero-ex/test/artifacts.ts

@@ -85,10 +85,12 @@ import * as MixinBancor from '../test/generated-artifacts/MixinBancor.json';
 import * as MixinCoFiX from '../test/generated-artifacts/MixinCoFiX.json';
 import * as MixinCryptoCom from '../test/generated-artifacts/MixinCryptoCom.json';
 import * as MixinCurve from '../test/generated-artifacts/MixinCurve.json';
+import * as MixinCurveV2 from '../test/generated-artifacts/MixinCurveV2.json';
 import * as MixinDodo from '../test/generated-artifacts/MixinDodo.json';
 import * as MixinDodoV2 from '../test/generated-artifacts/MixinDodoV2.json';
 import * as MixinKyber from '../test/generated-artifacts/MixinKyber.json';
 import * as MixinKyberDmm from '../test/generated-artifacts/MixinKyberDmm.json';
+import * as MixinLido from '../test/generated-artifacts/MixinLido.json';
 import * as MixinMakerPSM from '../test/generated-artifacts/MixinMakerPSM.json';
 import * as MixinMooniswap from '../test/generated-artifacts/MixinMooniswap.json';
 import * as MixinMStable from '../test/generated-artifacts/MixinMStable.json';
@@ -258,10 +260,12 @@ export const artifacts = {
     MixinCoFiX: MixinCoFiX as ContractArtifact,
     MixinCryptoCom: MixinCryptoCom as ContractArtifact,
     MixinCurve: MixinCurve as ContractArtifact,
+    MixinCurveV2: MixinCurveV2 as ContractArtifact,
     MixinDodo: MixinDodo as ContractArtifact,
     MixinDodoV2: MixinDodoV2 as ContractArtifact,
     MixinKyber: MixinKyber as ContractArtifact,
     MixinKyberDmm: MixinKyberDmm as ContractArtifact,
+    MixinLido: MixinLido as ContractArtifact,
     MixinMStable: MixinMStable as ContractArtifact,
     MixinMakerPSM: MixinMakerPSM as ContractArtifact,
     MixinMooniswap: MixinMooniswap as ContractArtifact,

contracts/zero-ex/test/wrappers.ts

@@ -83,10 +83,12 @@ export * from '../test/generated-wrappers/mixin_bancor';
 export * from '../test/generated-wrappers/mixin_co_fi_x';
 export * from '../test/generated-wrappers/mixin_crypto_com';
 export * from '../test/generated-wrappers/mixin_curve';
+export * from '../test/generated-wrappers/mixin_curve_v2';
 export * from '../test/generated-wrappers/mixin_dodo';
 export * from '../test/generated-wrappers/mixin_dodo_v2';
 export * from '../test/generated-wrappers/mixin_kyber';
 export * from '../test/generated-wrappers/mixin_kyber_dmm';
+export * from '../test/generated-wrappers/mixin_lido';
 export * from '../test/generated-wrappers/mixin_m_stable';
 export * from '../test/generated-wrappers/mixin_maker_p_s_m';
 export * from '../test/generated-wrappers/mixin_mooniswap';

contracts/zero-ex/tsconfig.json

@@ -116,10 +116,12 @@
         "test/generated-artifacts/MixinCoFiX.json",
         "test/generated-artifacts/MixinCryptoCom.json",
         "test/generated-artifacts/MixinCurve.json",
+        "test/generated-artifacts/MixinCurveV2.json",
         "test/generated-artifacts/MixinDodo.json",
         "test/generated-artifacts/MixinDodoV2.json",
         "test/generated-artifacts/MixinKyber.json",
         "test/generated-artifacts/MixinKyberDmm.json",
+        "test/generated-artifacts/MixinLido.json",
         "test/generated-artifacts/MixinMStable.json",
         "test/generated-artifacts/MixinMakerPSM.json",
         "test/generated-artifacts/MixinMooniswap.json",

packages/asset-swapper/CHANGELOG.json

@@ -1,4 +1,60 @@
 [
+    {
+        "version": "7.0.0",
+        "changes": [
+            {
+                "note": "SwapRevertSampler. Refactored sampler to use exchange functions. Remove gas schedule.",
+                "pr": 245
+            }
+        ]
+    },
+    {
+        "timestamp": 1624562704,
+        "version": "6.18.2",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
+    {
+        "version": "6.18.1",
+        "changes": [
+            {
+                "note": "FirebirdOneSwap, ApeSwap. New hop tokens: DFYN, BANANA, WEXPOLY",
+                "pr": 265
+            }
+        ],
+        "timestamp": 1624405040
+    },
+    {
+        "version": "6.18.0",
+        "changes": [
+            {
+                "note": "Add Lido stETH deposit integration",
+                "pr": 260
+            }
+        ],
+        "timestamp": 1624356181
+    },
+    {
+        "version": "6.17.3",
+        "changes": [
+            {
+                "note": "QUICK, TITAN, IRON as intermediate tokens, integrating WaultSwap and Polydex for Polygon, Curve renBTC pool"
+            }
+        ],
+        "timestamp": 1623807529
+    },
+    {
+        "timestamp": 1623382456,
+        "version": "6.17.2",
+        "changes": [
+            {
+                "note": "Dependencies updated"
+            }
+        ]
+    },
     {
         "timestamp": 1622609597,
         "version": "6.17.1",

packages/asset-swapper/CHANGELOG.md

@@ -5,6 +5,26 @@ Edit the package's CHANGELOG.json file only.
 
 CHANGELOG
 
+## v6.18.2 - _June 24, 2021_
+
+    * Dependencies updated
+
+## v6.18.1 - _June 22, 2021_
+
+    * FirebirdOneSwap, ApeSwap. New hop tokens: DFYN, BANANA, WEXPOLY (#265)
+
+## v6.18.0 - _June 22, 2021_
+
+    * Add Lido stETH deposit integration (#260)
+
+## v6.17.3 - _June 16, 2021_
+
+    * QUICK, TITAN, IRON as intermediate tokens, integrating WaultSwap and Polydex for Polygon, Curve renBTC pool
+
+## v6.17.2 - _June 11, 2021_
+
+    * Dependencies updated
+
 ## v6.17.1 - _June 2, 2021_
 
     * Dependencies updated

packages/asset-swapper/contracts/src/ApproximateBuys.sol

@@ -1,144 +0,0 @@
-// SPDX-License-Identifier: Apache-2.0
-/*
-
-  Copyright 2020 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.6;
-pragma experimental ABIEncoderV2;
-
-import "@0x/contracts-utils/contracts/src/v06/LibMathV06.sol";
-
-
-contract ApproximateBuys {
-
-    /// @dev Information computing buy quotes for sources that do not have native
-    ///      buy quote support.
-    struct ApproximateBuyQuoteOpts {
-        // Arbitrary maker token data to pass to `getSellQuoteCallback`.
-        bytes makerTokenData;
-        // Arbitrary taker token data to pass to `getSellQuoteCallback`.
-        bytes takerTokenData;
-        // Callback to retrieve a sell quote.
-        function (bytes memory, bytes memory, uint256)
-            internal
-            view
-            returns (uint256) getSellQuoteCallback;
-    }
-
-    uint256 private constant ONE_HUNDED_PERCENT_BPS = 1e4;
-    /// @dev Maximum approximate (positive) error rate when approximating a buy quote.
-    uint256 private constant APPROXIMATE_BUY_TARGET_EPSILON_BPS = 0.0005e4;
-    /// @dev Maximum iterations to perform when approximating a buy quote.
-    uint256 private constant APPROXIMATE_BUY_MAX_ITERATIONS = 5;
-
-    function _sampleApproximateBuys(
-        ApproximateBuyQuoteOpts memory opts,
-        uint256[] memory makerTokenAmounts
-    )
-        internal
-        view
-        returns (uint256[] memory takerTokenAmounts)
-    {
-        takerTokenAmounts = new uint256[](makerTokenAmounts.length);
-        if (makerTokenAmounts.length == 0) {
-            return takerTokenAmounts;
-        }
-
-        uint256 sellAmount = opts.getSellQuoteCallback(
-            opts.makerTokenData,
-            opts.takerTokenData,
-            makerTokenAmounts[0]
-        );
-        if (sellAmount == 0) {
-            return takerTokenAmounts;
-        }
-
-        uint256 buyAmount = opts.getSellQuoteCallback(
-            opts.takerTokenData,
-            opts.makerTokenData,
-            sellAmount
-        );
-        if (buyAmount == 0) {
-            return takerTokenAmounts;
-        }
-
-        for (uint256 i = 0; i < makerTokenAmounts.length; i++) {
-            for (uint256 iter = 0; iter < APPROXIMATE_BUY_MAX_ITERATIONS; iter++) {
-                // adjustedSellAmount = previousSellAmount * (target/actual) * JUMP_MULTIPLIER
-                sellAmount = _safeGetPartialAmountCeil(
-                    makerTokenAmounts[i],
-                    buyAmount,
-                    sellAmount
-                );
-                if (sellAmount == 0) {
-                    break;
-                }
-                sellAmount = _safeGetPartialAmountCeil(
-                    (ONE_HUNDED_PERCENT_BPS + APPROXIMATE_BUY_TARGET_EPSILON_BPS),
-                    ONE_HUNDED_PERCENT_BPS,
-                    sellAmount
-                );
-                if (sellAmount == 0) {
-                    break;
-                }
-                uint256 _buyAmount = opts.getSellQuoteCallback(
-                    opts.takerTokenData,
-                    opts.makerTokenData,
-                    sellAmount
-                );
-                if (_buyAmount == 0) {
-                    break;
-                }
-                // We re-use buyAmount next iteration, only assign if it is
-                // non zero
-                buyAmount = _buyAmount;
-                // If we've reached our goal, exit early
-                if (buyAmount >= makerTokenAmounts[i]) {
-                    uint256 eps =
-                        (buyAmount - makerTokenAmounts[i]) * ONE_HUNDED_PERCENT_BPS /
-                        makerTokenAmounts[i];
-                    if (eps <= APPROXIMATE_BUY_TARGET_EPSILON_BPS) {
-                        break;
-                    }
-                }
-            }
-            // We do our best to close in on the requested amount, but we can either over buy or under buy and exit
-            // if we hit a max iteration limit
-            // We scale the sell amount to get the approximate target
-            takerTokenAmounts[i] = _safeGetPartialAmountCeil(
-                makerTokenAmounts[i],
-                buyAmount,
-                sellAmount
-            );
-        }
-    }
-
-    function _safeGetPartialAmountCeil(
-        uint256 numerator,
-        uint256 denominator,
-        uint256 target
-    )
-        internal
-        view
-        returns (uint256 partialAmount)
-    {
-        if (numerator == 0 || target == 0 || denominator == 0) return 0;
-        uint256 c = numerator * target;
-        if (c / numerator != target) return 0;
-        return (c + (denominator - 1)) / denominator;
-    }
-}

packages/asset-swapper/contracts/src/BalancerSampler.sol

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: Apache-2.0
 /*
 
-  Copyright 2020 ZeroEx Intl.
+  Copyright 2021 ZeroEx Intl.
 
   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
@@ -20,26 +20,29 @@
 pragma solidity ^0.6;
 pragma experimental ABIEncoderV2;
 
-import "./interfaces/IBalancer.sol";
+import "@0x/contracts-zero-ex/contracts/src/transformers/bridges/mixins/MixinBalancer.sol";
+import "./SwapRevertSampler.sol";
 
+contract BalancerSampler is
+    MixinBalancer,
+    SwapRevertSampler
+{
 
-contract BalancerSampler {
-
-    /// @dev Base gas limit for Balancer calls.
-    uint256 constant private BALANCER_CALL_GAS = 300e3; // 300k
-
-    // Balancer math constants
-    // https://github.com/balancer-labs/balancer-core/blob/master/contracts/BConst.sol
-    uint256 constant private BONE = 10 ** 18;
-    uint256 constant private MAX_IN_RATIO = BONE / 2;
-    uint256 constant private MAX_OUT_RATIO = (BONE / 3) + 1 wei;
-
-    struct BalancerState {
-        uint256 takerTokenBalance;
-        uint256 makerTokenBalance;
-        uint256 takerTokenWeight;
-        uint256 makerTokenWeight;
-        uint256 swapFee;
+    function sampleSwapFromBalancer(
+        address sellToken,
+        address buyToken,
+        bytes memory bridgeData,
+        uint256 takerTokenAmount
+    )
+        external
+        returns (uint256)
+    {
+        return _tradeBalancer(
+            IERC20TokenV06(sellToken),
+            IERC20TokenV06(buyToken),
+            takerTokenAmount,
+            bridgeData
+        );
     }
 
     /// @dev Sample sell quotes from Balancer.
@@ -47,6 +50,7 @@ contract BalancerSampler {
     /// @param takerToken Address of the taker token (what to sell).
     /// @param makerToken Address of the maker token (what to buy).
     /// @param takerTokenAmounts Taker token sell amount for each sample.
+    /// @return gasUsed gas consumed in each sample sell
     /// @return makerTokenAmounts Maker amounts bought at each taker token
     ///         amount.
     function sampleSellsFromBalancer(
@@ -56,52 +60,17 @@ contract BalancerSampler {
         uint256[] memory takerTokenAmounts
     )
         public
-        view
-        returns (uint256[] memory makerTokenAmounts)
+        returns (uint256[] memory gasUsed, uint256[] memory makerTokenAmounts)
     {
-        IBalancer pool = IBalancer(poolAddress);
-        uint256 numSamples = takerTokenAmounts.length;
-        makerTokenAmounts = new uint256[](numSamples);
-        if (!pool.isBound(takerToken) || !pool.isBound(makerToken)) {
-            return makerTokenAmounts;
-        }
-
-        BalancerState memory poolState;
-        poolState.takerTokenBalance = pool.getBalance(takerToken);
-        poolState.makerTokenBalance = pool.getBalance(makerToken);
-        poolState.takerTokenWeight = pool.getDenormalizedWeight(takerToken);
-        poolState.makerTokenWeight = pool.getDenormalizedWeight(makerToken);
-        poolState.swapFee = pool.getSwapFee();
-
-        for (uint256 i = 0; i < numSamples; i++) {
-            // Handles this revert scenario:
-            // https://github.com/balancer-labs/balancer-core/blob/master/contracts/BPool.sol#L443
-            if (takerTokenAmounts[i] > _bmul(poolState.takerTokenBalance, MAX_IN_RATIO)) {
-                break;
-            }
-            try
-                pool.calcOutGivenIn
-                    {gas: BALANCER_CALL_GAS}
-                    (
-                        poolState.takerTokenBalance,
-                        poolState.takerTokenWeight,
-                        poolState.makerTokenBalance,
-                        poolState.makerTokenWeight,
-                        takerTokenAmounts[i],
-                        poolState.swapFee
-                    )
-                returns (uint256 amount)
-            {
-                makerTokenAmounts[i] = amount;
-                // Break early if there are 0 amounts
-                if (makerTokenAmounts[i] == 0) {
-                    break;
-                }
-            } catch (bytes memory) {
-                // Swallow failures, leaving all results as zero.
-                break;
-            }
-        }
+        (gasUsed, makerTokenAmounts) = _sampleSwapQuotesRevert(
+            SwapRevertSamplerQuoteOpts({
+                sellToken: takerToken,
+                buyToken: makerToken,
+                bridgeData: abi.encode(poolAddress),
+                getSwapQuoteCallback: this.sampleSwapFromBalancer
+            }),
+            takerTokenAmounts
+        );
     }
 
     /// @dev Sample buy quotes from Balancer.
@@ -109,6 +78,7 @@ contract BalancerSampler {
     /// @param takerToken Address of the taker token (what to sell).
     /// @param makerToken Address of the maker token (what to buy).
     /// @param makerTokenAmounts Maker token buy amount for each sample.
+    /// @return gasUsed gas consumed in each sample sell
     /// @return takerTokenAmounts Taker amounts sold at each maker token
     ///         amount.
     function sampleBuysFromBalancer(
@@ -118,74 +88,18 @@ contract BalancerSampler {
         uint256[] memory makerTokenAmounts
     )
         public
-        view
-        returns (uint256[] memory takerTokenAmounts)
+        returns (uint256[] memory gasUsed, uint256[] memory takerTokenAmounts)
     {
-        IBalancer pool = IBalancer(poolAddress);
-        uint256 numSamples = makerTokenAmounts.length;
-        takerTokenAmounts = new uint256[](numSamples);
-        if (!pool.isBound(takerToken) || !pool.isBound(makerToken)) {
-            return takerTokenAmounts;
-        }
+        (gasUsed, takerTokenAmounts) = _sampleSwapApproximateBuys(
+            SwapRevertSamplerBuyQuoteOpts({
+                sellToken: takerToken,
+                buyToken: makerToken,
+                sellTokenData: abi.encode(poolAddress),
+                buyTokenData: abi.encode(poolAddress),
+                getSwapQuoteCallback: this.sampleSwapFromBalancer
+            }),
+            makerTokenAmounts
+        );
 
-        BalancerState memory poolState;
-        poolState.takerTokenBalance = pool.getBalance(takerToken);
-        poolState.makerTokenBalance = pool.getBalance(makerToken);
-        poolState.takerTokenWeight = pool.getDenormalizedWeight(takerToken);
-        poolState.makerTokenWeight = pool.getDenormalizedWeight(makerToken);
-        poolState.swapFee = pool.getSwapFee();
-
-        for (uint256 i = 0; i < numSamples; i++) {
-            // Handles this revert scenario:
-            // https://github.com/balancer-labs/balancer-core/blob/master/contracts/BPool.sol#L505
-            if (makerTokenAmounts[i] > _bmul(poolState.makerTokenBalance, MAX_OUT_RATIO)) {
-                break;
-            }
-            try
-                pool.calcInGivenOut
-                    {gas: BALANCER_CALL_GAS}
-                    (
-                        poolState.takerTokenBalance,
-                        poolState.takerTokenWeight,
-                        poolState.makerTokenBalance,
-                        poolState.makerTokenWeight,
-                        makerTokenAmounts[i],
-                        poolState.swapFee
-                    )
-                returns (uint256 amount)
-            {
-                takerTokenAmounts[i] = amount;
-                // Break early if there are 0 amounts
-                if (takerTokenAmounts[i] == 0) {
-                    break;
-                }
-            } catch (bytes memory) {
-                // Swallow failures, leaving all results as zero.
-                break;
-            }
-        }
-    }
-
-    /// @dev Hacked version of Balancer's `bmul` function, returning 0 instead
-    ///      of reverting.
-    ///      https://github.com/balancer-labs/balancer-core/blob/master/contracts/BNum.sol#L63-L73
-    /// @param a The first operand.
-    /// @param b The second operand.
-    /// @param c The result of the multiplication, or 0 if `bmul` would've reverted.
-    function _bmul(uint256 a, uint256 b)
-        private
-        pure
-        returns (uint256 c)
-    {
-        uint c0 = a * b;
-        if (a != 0 && c0 / a != b) {
-            return 0;
-        }
-        uint c1 = c0 + (BONE / 2);
-        if (c1 < c0) {
-            return 0;
-        }
-        uint c2 = c1 / BONE;
-        return c2;
     }
 }

packages/asset-swapper/contracts/src/BalancerV2Sampler.sol

@@ -20,44 +20,29 @@
 pragma solidity ^0.6;
 pragma experimental ABIEncoderV2;
 
-import "./SamplerUtils.sol";
+import "@0x/contracts-zero-ex/contracts/src/transformers/bridges/mixins/MixinBalancerV2.sol";
+import "./SwapRevertSampler.sol";
 
-/// @dev Minimal Balancer V2 Vault interface
-///      for documentation refer to https://github.com/balancer-labs/balancer-core-v2/blob/master/contracts/vault/interfaces/IVault.sol
-interface IBalancerV2Vault {
-    enum SwapKind { GIVEN_IN, GIVEN_OUT }
+contract BalancerV2Sampler is
+    MixinBalancerV2,
+    SwapRevertSampler
+{
 
-    struct BatchSwapStep {
-        bytes32 poolId;
-        uint256 assetInIndex;
-        uint256 assetOutIndex;
-        uint256 amount;
-        bytes userData;
-    }
-
-    struct FundManagement {
-        address sender;
-        bool fromInternalBalance;
-        address payable recipient;
-        bool toInternalBalance;
-    }
-
-    function queryBatchSwap(
-        SwapKind kind,
-        BatchSwapStep[] calldata swaps,
-        IAsset[] calldata assets,
-        FundManagement calldata funds
-    ) external returns (int256[] memory assetDeltas);
-}
-interface IAsset {
-    // solhint-disable-previous-line no-empty-blocks
-}
-
-contract BalancerV2Sampler is SamplerUtils {
-
-    struct BalancerV2PoolInfo {
-        bytes32 poolId;
-        address vault;
+    function sampleSwapFromBalancerV2(
+        address sellToken,
+        address buyToken,
+        bytes memory bridgeData,
+        uint256 takerTokenAmount
+    )
+        external
+        returns (uint256)
+    {
+        return _tradeBalancerV2(
+            IERC20TokenV06(sellToken),
+            IERC20TokenV06(buyToken),
+            takerTokenAmount,
+            bridgeData
+        );
     }
 
     /// @dev Sample sell quotes from Balancer V2.
@@ -65,48 +50,27 @@ contract BalancerV2Sampler is SamplerUtils {
     /// @param takerToken Address of the taker token (what to sell).
     /// @param makerToken Address of the maker token (what to buy).
     /// @param takerTokenAmounts Taker token sell amount for each sample.
+    /// @return gasUsed gas consumed in each sample sell
     /// @return makerTokenAmounts Maker amounts bought at each taker token
     ///         amount.
     function sampleSellsFromBalancerV2(
-        BalancerV2PoolInfo memory poolInfo,
+        BalancerV2BridgeData memory poolInfo,
         address takerToken,
         address makerToken,
         uint256[] memory takerTokenAmounts
     )
         public
-        returns (uint256[] memory makerTokenAmounts)
+        returns (uint256[] memory gasUsed, uint256[] memory makerTokenAmounts)
     {
-        _assertValidPair(makerToken, takerToken);
-        IBalancerV2Vault vault = IBalancerV2Vault(poolInfo.vault);
-        IAsset[] memory swapAssets = new IAsset[](2);
-        swapAssets[0] = IAsset(takerToken);
-        swapAssets[1] = IAsset(makerToken);
-
-        uint256 numSamples = takerTokenAmounts.length;
-        makerTokenAmounts = new uint256[](numSamples);
-        IBalancerV2Vault.FundManagement memory swapFunds =
-            _createSwapFunds();
-
-        for (uint256 i = 0; i < numSamples; i++) {
-            IBalancerV2Vault.BatchSwapStep[] memory swapSteps =
-                _createSwapSteps(poolInfo, takerTokenAmounts[i]);
-
-            try
-                // For sells we specify the takerToken which is what the vault will receive from the trade
-                vault.queryBatchSwap(IBalancerV2Vault.SwapKind.GIVEN_IN, swapSteps, swapAssets, swapFunds)
-            // amounts represent pool balance deltas from the swap (incoming balance, outgoing balance)
-            returns (int256[] memory amounts) {
-                // Outgoing balance is negative so we need to flip the sign
-                int256 amountOutFromPool = amounts[1] * -1;
-                if (amountOutFromPool <= 0) {
-                    break;
-                }
-                makerTokenAmounts[i] = uint256(amountOutFromPool);
-            } catch (bytes memory) {
-                // Swallow failures, leaving all results as zero.
-                break;
-            }
-        }
+        (gasUsed, makerTokenAmounts) = _sampleSwapQuotesRevert(
+            SwapRevertSamplerQuoteOpts({
+                sellToken: takerToken,
+                buyToken: makerToken,
+                bridgeData: abi.encode(poolInfo),
+                getSwapQuoteCallback: this.sampleSwapFromBalancerV2
+            }),
+            takerTokenAmounts
+        );
     }
 
     /// @dev Sample buy quotes from Balancer V2.
@@ -114,76 +78,27 @@ contract BalancerV2Sampler is SamplerUtils {
     /// @param takerToken Address of the taker token (what to sell).
     /// @param makerToken Address of the maker token (what to buy).
     /// @param makerTokenAmounts Maker token buy amount for each sample.
+    /// @return gasUsed gas consumed in each sample sell
     /// @return takerTokenAmounts Taker amounts sold at each maker token
     ///         amount.
     function sampleBuysFromBalancerV2(
-        BalancerV2PoolInfo memory poolInfo,
+        BalancerV2BridgeData memory poolInfo,
         address takerToken,
         address makerToken,
         uint256[] memory makerTokenAmounts
     )
         public
-        returns (uint256[] memory takerTokenAmounts)
+        returns (uint256[] memory gasUsed, uint256[] memory takerTokenAmounts)
     {
-        _assertValidPair(makerToken, takerToken);
-        IBalancerV2Vault vault = IBalancerV2Vault(poolInfo.vault);
-        IAsset[] memory swapAssets = new IAsset[](2);
-        swapAssets[0] = IAsset(takerToken);
-        swapAssets[1] = IAsset(makerToken);
-
-        uint256 numSamples = makerTokenAmounts.length;
-        takerTokenAmounts = new uint256[](numSamples);
-        IBalancerV2Vault.FundManagement memory swapFunds =
-            _createSwapFunds();
-
-        for (uint256 i = 0; i < numSamples; i++) {
-            IBalancerV2Vault.BatchSwapStep[] memory swapSteps =
-                _createSwapSteps(poolInfo, makerTokenAmounts[i]);
-
-            try
-                // For buys we specify the makerToken which is what taker will receive from the trade
-                vault.queryBatchSwap(IBalancerV2Vault.SwapKind.GIVEN_OUT, swapSteps, swapAssets, swapFunds)
-            returns (int256[] memory amounts) {
-                int256 amountIntoPool = amounts[0];
-                if (amountIntoPool <= 0) {
-                    break;
-                }
-                takerTokenAmounts[i] = uint256(amountIntoPool);
-            } catch (bytes memory) {
-                // Swallow failures, leaving all results as zero.
-                break;
-            }
-        }
-    }
-
-    function _createSwapSteps(
-        BalancerV2PoolInfo memory poolInfo,
-        uint256 amount
-    ) private pure returns (IBalancerV2Vault.BatchSwapStep[] memory) {
-        IBalancerV2Vault.BatchSwapStep[] memory swapSteps =
-            new IBalancerV2Vault.BatchSwapStep[](1);
-        swapSteps[0] = IBalancerV2Vault.BatchSwapStep({
-            poolId: poolInfo.poolId,
-            assetInIndex: 0,
-            assetOutIndex: 1,
-            amount: amount,
-            userData: ""
-        });
-
-        return swapSteps;
-    }
-
-    function _createSwapFunds()
-        private
-        view
-        returns (IBalancerV2Vault.FundManagement memory)
-    {
-        return
-            IBalancerV2Vault.FundManagement({
-                sender: address(this),
-                fromInternalBalance: false,
-                recipient: payable(address(this)),
-                toInternalBalance: false
-            });
+        (gasUsed, takerTokenAmounts) = _sampleSwapApproximateBuys(
+            SwapRevertSamplerBuyQuoteOpts({
+                sellToken: takerToken,
+                buyToken: makerToken,
+                sellTokenData: abi.encode(poolInfo),
+                buyTokenData: abi.encode(poolInfo),
+                getSwapQuoteCallback: this.sampleSwapFromBalancerV2
+            }),
+            makerTokenAmounts
+        );
     }
 }

packages/asset-swapper/contracts/src/BancorSampler.sol

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: Apache-2.0
 /*
 
-  Copyright 2020 ZeroEx Intl.
+  Copyright 2021 ZeroEx Intl.
 
   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
@@ -20,11 +20,21 @@
 pragma solidity ^0.6;
 pragma experimental ABIEncoderV2;
 
-import "./interfaces/IBancor.sol";
+import "@0x/contracts-zero-ex/contracts/src/transformers/bridges/mixins/MixinBancor.sol";
+import "./SwapRevertSampler.sol";
 
 contract CompilerHack {}
 
-contract BancorSampler is CompilerHack {
+contract BancorSampler is
+    CompilerHack,
+    MixinBancor,
+    SwapRevertSampler
+{
+
+    constructor(IEtherTokenV06 weth)
+        public
+        MixinBancor(weth)
+    { }
 
     /// @dev Base gas limit for Bancor calls.
     uint256 constant private BANCOR_CALL_GAS = 300e3; // 300k
@@ -34,6 +44,23 @@ contract BancorSampler is CompilerHack {
         address[][] paths;
     }
 
+    function sampleSwapFromBancor(
+        address sellToken,
+        address buyToken,
+        bytes memory bridgeData,
+        uint256 takerTokenAmount
+    )
+        external
+        returns (uint256)
+    {
+        return _tradeBancorInternal(
+            _getNativeWrappedToken(),
+            IERC20TokenV06(buyToken),
+            takerTokenAmount,
+            bridgeData
+        );
+    }
+
     /// @dev Sample sell quotes from Bancor.
     /// @param opts BancorSamplerOpts The Bancor registry contract address and paths
     /// @param takerToken Address of the taker token (what to sell).
@@ -41,6 +68,7 @@ contract BancorSampler is CompilerHack {
     /// @param takerTokenAmounts Taker token sell amount for each sample.
     /// @return bancorNetwork the Bancor Network address
     /// @return path the selected conversion path from bancor
+    /// @return gasUsed gas consumed in each sample sell
     /// @return makerTokenAmounts Maker amounts bought at each taker token
     ///         amount.
     function sampleSellsFromBancor(
@@ -50,34 +78,30 @@ contract BancorSampler is CompilerHack {
         uint256[] memory takerTokenAmounts
     )
         public
-        view
-        returns (address bancorNetwork, address[] memory path, uint256[] memory makerTokenAmounts)
+        returns (
+            address bancorNetwork,
+            address[] memory path,
+            uint256[] memory gasUsed,
+            uint256[] memory makerTokenAmounts
+        )
     {
         if (opts.paths.length == 0) {
-            return (bancorNetwork, path, makerTokenAmounts);
+            return (bancorNetwork, path, gasUsed, makerTokenAmounts);
         }
-        (bancorNetwork, path) = _findBestPath(opts, takerToken, makerToken, takerTokenAmounts);
-        makerTokenAmounts = new uint256[](takerTokenAmounts.length);
 
-        for (uint256 i = 0; i < makerTokenAmounts.length; i++) {
-            try
-                IBancorNetwork(bancorNetwork)
-                    .rateByPath
-                        {gas: BANCOR_CALL_GAS}
-                        (path, takerTokenAmounts[i])
-                returns (uint256 amount)
-            {
-                makerTokenAmounts[i] = amount;
-                // Break early if there are 0 amounts
-                if (makerTokenAmounts[i] == 0) {
-                    break;
-                }
-            } catch {
-                // Swallow failures, leaving all results as zero.
-                break;
-            }
-        }
-        return (bancorNetwork, path, makerTokenAmounts);
+        (bancorNetwork, path) = _findBestPath(opts, takerToken, makerToken, takerTokenAmounts);
+
+        (gasUsed, makerTokenAmounts) = _sampleSwapQuotesRevert(
+            SwapRevertSamplerQuoteOpts({
+                sellToken: takerToken,
+                buyToken: makerToken,
+                bridgeData: abi.encode(bancorNetwork, path),
+                getSwapQuoteCallback: this.sampleSwapFromBancor
+            }),
+            takerTokenAmounts
+        );
+
+        return (bancorNetwork, path, gasUsed, makerTokenAmounts);
     }
 
     /// @dev Sample buy quotes from Bancor. Unimplemented
@@ -87,6 +111,7 @@ contract BancorSampler is CompilerHack {
     /// @param makerTokenAmounts Maker token buy amount for each sample.
     /// @return bancorNetwork the Bancor Network address
     /// @return path the selected conversion path from bancor
+    /// @return gasUsed gas consumed in each sample sell
     /// @return takerTokenAmounts Taker amounts sold at each maker token
     ///         amount.
     function sampleBuysFromBancor(
@@ -97,7 +122,7 @@ contract BancorSampler is CompilerHack {
     )
         public
         view
-        returns (address bancorNetwork, address[] memory path, uint256[] memory takerTokenAmounts)
+        returns (address bancorNetwork, address[] memory path, uint256[] memory gasUsed, uint256[] memory takerTokenAmounts)
     {
     }
 

packages/asset-swapper/contracts/src/CurveSampler.sol

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: Apache-2.0
 /*
 
-  Copyright 2020 ZeroEx Intl.
+  Copyright 2021 ZeroEx Intl.
 
   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
@@ -20,142 +20,99 @@
 pragma solidity ^0.6;
 pragma experimental ABIEncoderV2;
 
-import "./interfaces/ICurve.sol";
-import "./ApproximateBuys.sol";
-import "./SamplerUtils.sol";
+import "@0x/contracts-zero-ex/contracts/src/transformers/bridges/mixins/MixinCurve.sol";
+import "./SwapRevertSampler.sol";
 
 
 contract CurveSampler is
-    SamplerUtils,
-    ApproximateBuys
+    MixinCurve,
+    SwapRevertSampler
 {
-    /// @dev Information for sampling from curve sources.
-    struct CurveInfo {
-        address poolAddress;
-        bytes4 sellQuoteFunctionSelector;
-        bytes4 buyQuoteFunctionSelector;
-    }
 
-    /// @dev Base gas limit for Curve calls. Some Curves have multiple tokens
-    ///      So a reasonable ceil is 150k per token. Biggest Curve has 4 tokens.
-    uint256 constant private CURVE_CALL_GAS = 2000e3; // Was 600k for Curve but SnowSwap is using 1500k+
+    constructor(IEtherTokenV06 weth)
+        public
+        MixinCurve(weth)
+    { }
+
+    function sampleSwapFromCurve(
+        address sellToken,
+        address buyToken,
+        bytes memory bridgeData,
+        uint256 takerTokenAmount
+    )
+        external
+        returns (uint256)
+    {
+        return _tradeCurveInternal(
+            _getNativeWrappedToken(),
+            IERC20TokenV06(sellToken),
+            IERC20TokenV06(buyToken),
+            takerTokenAmount,
+            bridgeData
+        );
+    }
 
     /// @dev Sample sell quotes from Curve.
     /// @param curveInfo Curve information specific to this token pair.
-    /// @param fromTokenIdx Index of the taker token (what to sell).
-    /// @param toTokenIdx Index of the maker token (what to buy).
+    /// @param takerToken The taker token to sell.
+    /// @param makerToken The maker token to buy.
     /// @param takerTokenAmounts Taker token sell amount for each sample.
+    /// @return gasUsed gas consumed in each sample sell
     /// @return makerTokenAmounts Maker amounts bought at each taker token
     ///         amount.
     function sampleSellsFromCurve(
-        CurveInfo memory curveInfo,
-        int128 fromTokenIdx,
-        int128 toTokenIdx,
+        CurveBridgeData memory curveInfo,
+        address takerToken,
+        address makerToken,
         uint256[] memory takerTokenAmounts
     )
         public
-        view
-        returns (uint256[] memory makerTokenAmounts)
+        returns (uint256[] memory gasUsed, uint256[] memory makerTokenAmounts)
     {
-        uint256 numSamples = takerTokenAmounts.length;
-        makerTokenAmounts = new uint256[](numSamples);
-        for (uint256 i = 0; i < numSamples; i++) {
-            (bool didSucceed, bytes memory resultData) =
-                curveInfo.poolAddress.staticcall.gas(CURVE_CALL_GAS)(
-                    abi.encodeWithSelector(
-                        curveInfo.sellQuoteFunctionSelector,
-                        fromTokenIdx,
-                        toTokenIdx,
-                        takerTokenAmounts[i]
-                    ));
-            uint256 buyAmount = 0;
-            if (didSucceed) {
-                buyAmount = abi.decode(resultData, (uint256));
-            }
-            makerTokenAmounts[i] = buyAmount;
-            // Break early if there are 0 amounts
-            if (makerTokenAmounts[i] == 0) {
-                break;
-            }
-        }
+        (gasUsed, makerTokenAmounts) = _sampleSwapQuotesRevert(
+            SwapRevertSamplerQuoteOpts({
+                sellToken: takerToken,
+                buyToken: makerToken,
+                bridgeData: abi.encode(curveInfo),
+                getSwapQuoteCallback: this.sampleSwapFromCurve
+            }),
+            takerTokenAmounts
+        );
     }
 
     /// @dev Sample buy quotes from Curve.
     /// @param curveInfo Curve information specific to this token pair.
-    /// @param fromTokenIdx Index of the taker token (what to sell).
-    /// @param toTokenIdx Index of the maker token (what to buy).
+    /// @param takerToken The taker token to sell.
+    /// @param makerToken The maker token to buy.
     /// @param makerTokenAmounts Maker token buy amount for each sample.
+    /// @return gasUsed gas consumed in each sample sell
     /// @return takerTokenAmounts Taker amounts sold at each maker token
     ///         amount.
     function sampleBuysFromCurve(
-        CurveInfo memory curveInfo,
-        int128 fromTokenIdx,
-        int128 toTokenIdx,
+        CurveBridgeData memory curveInfo,
+        address takerToken,
+        address makerToken,
         uint256[] memory makerTokenAmounts
     )
         public
-        view
-        returns (uint256[] memory takerTokenAmounts)
+        returns (uint256[] memory gasUsed, uint256[] memory takerTokenAmounts)
     {
-        if (curveInfo.buyQuoteFunctionSelector == bytes4(0)) {
-            // Buys not supported on this curve, so approximate it.
-            return _sampleApproximateBuys(
-                ApproximateBuyQuoteOpts({
-                    makerTokenData: abi.encode(toTokenIdx, curveInfo),
-                    takerTokenData: abi.encode(fromTokenIdx, curveInfo),
-                    getSellQuoteCallback: _sampleSellForApproximateBuyFromCurve
-                }),
-                makerTokenAmounts
-            );
-        }
-        uint256 numSamples = makerTokenAmounts.length;
-        takerTokenAmounts = new uint256[](numSamples);
-        for (uint256 i = 0; i < numSamples; i++) {
-            (bool didSucceed, bytes memory resultData) =
-                curveInfo.poolAddress.staticcall.gas(CURVE_CALL_GAS)(
-                    abi.encodeWithSelector(
-                        curveInfo.buyQuoteFunctionSelector,
-                        fromTokenIdx,
-                        toTokenIdx,
-                        makerTokenAmounts[i]
-                    ));
-            uint256 sellAmount = 0;
-            if (didSucceed) {
-                sellAmount = abi.decode(resultData, (uint256));
-            }
-            takerTokenAmounts[i] = sellAmount;
-            // Break early if there are 0 amounts
-            if (takerTokenAmounts[i] == 0) {
-                break;
-            }
-        }
-    }
-
-    function _sampleSellForApproximateBuyFromCurve(
-        bytes memory takerTokenData,
-        bytes memory makerTokenData,
-        uint256 sellAmount
-    )
-        private
-        view
-        returns (uint256 buyAmount)
-    {
-        (int128 takerTokenIdx, CurveInfo memory curveInfo) =
-            abi.decode(takerTokenData, (int128, CurveInfo));
-        (int128 makerTokenIdx) =
-            abi.decode(makerTokenData, (int128));
-        (bool success, bytes memory resultData) =
-            address(this).staticcall(abi.encodeWithSelector(
-                this.sampleSellsFromCurve.selector,
-                curveInfo,
-                takerTokenIdx,
-                makerTokenIdx,
-                _toSingleValueArray(sellAmount)
-            ));
-        if (!success) {
-            return 0;
-        }
-        // solhint-disable-next-line indent
-        return abi.decode(resultData, (uint256[]))[0];
+        (gasUsed, takerTokenAmounts) = _sampleSwapApproximateBuys(
+            SwapRevertSamplerBuyQuoteOpts({
+                sellToken: takerToken,
+                buyToken: makerToken,
+                sellTokenData: abi.encode(curveInfo),
+                buyTokenData: abi.encode(
+                    CurveBridgeData({
+                        curveAddress: curveInfo.curveAddress,
+                        exchangeFunctionSelector: curveInfo.exchangeFunctionSelector,
+                        fromCoinIdx: curveInfo.toCoinIdx,
+                        toCoinIdx: curveInfo.fromCoinIdx
+                    })
+                ),
+                getSwapQuoteCallback: this.sampleSwapFromCurve
+            }),
+            makerTokenAmounts
+        );
     }
 }

packages/asset-swapper/contracts/src/CurveV2Sampler.sol

@@ -0,0 +1,112 @@
+// SPDX-License-Identifier: Apache-2.0
+/*
+
+  Copyright 2021 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.6;
+pragma experimental ABIEncoderV2;
+
+import "@0x/contracts-zero-ex/contracts/src/transformers/bridges/mixins/MixinCurveV2.sol";
+import "./SwapRevertSampler.sol";
+
+
+contract CurveV2Sampler is
+    MixinCurveV2,
+    SwapRevertSampler
+{
+
+    function sampleSwapFromCurveV2(
+        address sellToken,
+        address buyToken,
+        bytes memory bridgeData,
+        uint256 takerTokenAmount
+    )
+        external
+        returns (uint256)
+    {
+        return _tradeCurveV2(
+            IERC20TokenV06(sellToken),
+            IERC20TokenV06(buyToken),
+            takerTokenAmount,
+            bridgeData
+        );
+    }
+
+    /// @dev Sample sell quotes from Curve.
+    /// @param curveInfo Curve information specific to this token pair.
+    /// @param takerToken The taker token to sell.
+    /// @param makerToken The maker token to buy.
+    /// @param takerTokenAmounts Taker token sell amount for each sample.
+    /// @return gasUsed gas consumed in each sample sell
+    /// @return makerTokenAmounts Maker amounts bought at each taker token
+    ///         amount.
+    function sampleSellsFromCurveV2(
+        CurveBridgeDataV2 memory curveInfo,
+        address takerToken,
+        address makerToken,
+        uint256[] memory takerTokenAmounts
+    )
+        public
+        returns (uint256[] memory gasUsed, uint256[] memory makerTokenAmounts)
+    {
+        (gasUsed, makerTokenAmounts) = _sampleSwapQuotesRevert(
+            SwapRevertSamplerQuoteOpts({
+                sellToken: takerToken,
+                buyToken: makerToken,
+                bridgeData: abi.encode(curveInfo),
+                getSwapQuoteCallback: this.sampleSwapFromCurveV2
+            }),
+            takerTokenAmounts
+        );
+    }
+
+    /// @dev Sample buy quotes from Curve.
+    /// @param curveInfo Curve information specific to this token pair.
+    /// @param takerToken The taker token to sell.
+    /// @param makerToken The maker token to buy.
+    /// @param makerTokenAmounts Maker token buy amount for each sample.
+    /// @return gasUsed gas consumed in each sample sell
+    /// @return takerTokenAmounts Taker amounts sold at each maker token
+    ///         amount.
+    function sampleBuysFromCurveV2(
+        CurveBridgeDataV2 memory curveInfo,
+        address takerToken,
+        address makerToken,
+        uint256[] memory makerTokenAmounts
+    )
+        public
+        returns (uint256[] memory gasUsed, uint256[] memory takerTokenAmounts)
+    {
+        (gasUsed, takerTokenAmounts) = _sampleSwapApproximateBuys(
+            SwapRevertSamplerBuyQuoteOpts({
+                sellToken: takerToken,
+                buyToken: makerToken,
+                sellTokenData: abi.encode(curveInfo),
+                buyTokenData: abi.encode(
+                    CurveBridgeDataV2({
+                        curveAddress: curveInfo.curveAddress,
+                        exchangeFunctionSelector: curveInfo.exchangeFunctionSelector,
+                        fromCoinIdx: curveInfo.toCoinIdx,
+                        toCoinIdx: curveInfo.fromCoinIdx
+                    })
+                ),
+                getSwapQuoteCallback: this.sampleSwapFromCurveV2
+            }),
+            makerTokenAmounts
+        );
+    }
+}

packages/asset-swapper/contracts/src/DODOSampler.sol

@@ -20,35 +20,40 @@
 pragma solidity ^0.6;
 pragma experimental ABIEncoderV2;
 
-import "./ApproximateBuys.sol";
-import "./SamplerUtils.sol";
+import "@0x/contracts-zero-ex/contracts/src/transformers/bridges/mixins/MixinDodo.sol";
+import "./SwapRevertSampler.sol";
 
 
 interface IDODOZoo {
     function getDODO(address baseToken, address quoteToken) external view returns (address);
 }
 
-interface IDODOHelper {
-    function querySellQuoteToken(address dodo, uint256 amount) external view returns (uint256);
-}
-
-interface IDODO {
-    function querySellBaseToken(uint256 amount) external view returns (uint256);
-    function _TRADE_ALLOWED_() external view returns (bool);
-}
-
 contract DODOSampler is
-    SamplerUtils,
-    ApproximateBuys
+    MixinDodo,
+    SwapRevertSampler
 {
 
-    /// @dev Gas limit for DODO calls.
-    uint256 constant private DODO_CALL_GAS = 300e3; // 300k
     struct DODOSamplerOpts {
         address registry;
         address helper;
     }
 
+    function sampleSwapFromDodo(
+        address sellToken,
+        address buyToken,
+        bytes memory bridgeData,
+        uint256 takerTokenAmount
+    )
+        external
+        returns (uint256)
+    {
+        return _tradeDodo(
+            IERC20TokenV06(sellToken),
+            takerTokenAmount,
+            bridgeData
+        );
+    }
+
     /// @dev Sample sell quotes from DODO.
     /// @param opts DODOSamplerOpts DODO Registry and helper addresses
     /// @param takerToken Address of the taker token (what to sell).
@@ -56,6 +61,7 @@ contract DODOSampler is
     /// @param takerTokenAmounts Taker token sell amount for each sample.
     /// @return sellBase whether the bridge needs to sell the base token
     /// @return pool the DODO pool address
+    /// @return gasUsed gas consumed in each sample sell
     /// @return makerTokenAmounts Maker amounts bought at each taker token
     ///         amount.
     function sampleSellsFromDODO(
@@ -65,13 +71,13 @@ contract DODOSampler is
         uint256[] memory takerTokenAmounts
     )
         public
-        view
-        returns (bool sellBase, address pool, uint256[] memory makerTokenAmounts)
+        returns (
+            bool sellBase,
+            address pool,
+            uint256[] memory gasUsed,
+            uint256[] memory makerTokenAmounts
+        )
     {
-        _assertValidPair(makerToken, takerToken);
-        uint256 numSamples = takerTokenAmounts.length;
-        makerTokenAmounts = new uint256[](numSamples);
-
         pool = IDODOZoo(opts.registry).getDODO(takerToken, makerToken);
         address baseToken;
         // If pool exists we have the correct order of Base/Quote
@@ -82,29 +88,21 @@ contract DODOSampler is
             pool = IDODOZoo(opts.registry).getDODO(makerToken, takerToken);
             // No pool either direction
             if (address(pool) == address(0)) {
-                return (sellBase, pool, makerTokenAmounts);
+                return (sellBase, pool, gasUsed, makerTokenAmounts);
             }
             baseToken = makerToken;
             sellBase = false;
         }
 
-        // DODO Pool has been disabled
-        if (!IDODO(pool)._TRADE_ALLOWED_()) {
-            return (sellBase, pool, makerTokenAmounts);
-        }
-
-        for (uint256 i = 0; i < numSamples; i++) {
-            uint256 buyAmount = _sampleSellForApproximateBuyFromDODO(
-                abi.encode(takerToken, pool, baseToken, opts.helper), // taker token data
-                abi.encode(makerToken, pool, baseToken, opts.helper), // maker token data
-                takerTokenAmounts[i]
-            );
-            makerTokenAmounts[i] = buyAmount;
-            // Break early if there are 0 amounts
-            if (makerTokenAmounts[i] == 0) {
-                break;
-            }
-        }
+        (gasUsed, makerTokenAmounts) = _sampleSwapQuotesRevert(
+            SwapRevertSamplerQuoteOpts({
+                sellToken: takerToken,
+                buyToken: makerToken,
+                bridgeData: abi.encode(opts.helper, pool, sellBase),
+                getSwapQuoteCallback: this.sampleSwapFromDodo
+            }),
+            takerTokenAmounts
+        );
     }
 
     /// @dev Sample buy quotes from DODO.
@@ -114,6 +112,7 @@ contract DODOSampler is
     /// @param makerTokenAmounts Maker token sell amount for each sample.
     /// @return sellBase whether the bridge needs to sell the base token
     /// @return pool the DODO pool address
+    /// @return gasUsed gas consumed in each sample sell
     /// @return takerTokenAmounts Taker amounts sold at each maker token
     ///         amount.
     function sampleBuysFromDODO(
@@ -123,13 +122,13 @@ contract DODOSampler is
         uint256[] memory makerTokenAmounts
     )
         public
-        view
-        returns (bool sellBase, address pool, uint256[] memory takerTokenAmounts)
+        returns (
+            bool sellBase,
+            address pool,
+            uint256[] memory gasUsed,
+            uint256[] memory takerTokenAmounts
+        )
     {
-        _assertValidPair(makerToken, takerToken);
-        uint256 numSamples = makerTokenAmounts.length;
-        takerTokenAmounts = new uint256[](numSamples);
-
         // Pool is BASE/QUOTE
         // Look up the pool from the taker/maker combination
         pool = IDODOZoo(opts.registry).getDODO(takerToken, makerToken);
@@ -143,69 +142,21 @@ contract DODOSampler is
             pool = IDODOZoo(opts.registry).getDODO(makerToken, takerToken);
             // No pool either direction
             if (address(pool) == address(0)) {
-                return (sellBase, pool, takerTokenAmounts);
+                return (sellBase, pool, gasUsed, takerTokenAmounts);
             }
             baseToken = makerToken;
             sellBase = false;
         }
 
-        // DODO Pool has been disabled
-        if (!IDODO(pool)._TRADE_ALLOWED_()) {
-            return (sellBase, pool, takerTokenAmounts);
-        }
-
-        takerTokenAmounts = _sampleApproximateBuys(
-            ApproximateBuyQuoteOpts({
-                makerTokenData: abi.encode(makerToken, pool, baseToken, opts.helper),
-                takerTokenData: abi.encode(takerToken, pool, baseToken, opts.helper),
-                getSellQuoteCallback: _sampleSellForApproximateBuyFromDODO
+        (gasUsed, takerTokenAmounts) = _sampleSwapApproximateBuys(
+            SwapRevertSamplerBuyQuoteOpts({
+                sellToken: takerToken,
+                buyToken: makerToken,
+                sellTokenData: abi.encode(opts.helper, pool, sellBase),
+                buyTokenData: abi.encode(opts.helper, pool, !sellBase),
+                getSwapQuoteCallback: this.sampleSwapFromDodo
             }),
             makerTokenAmounts
         );
     }
-
-    function _sampleSellForApproximateBuyFromDODO(
-        bytes memory takerTokenData,
-        bytes memory /* makerTokenData */,
-        uint256 sellAmount
-    )
-        private
-        view
-        returns (uint256)
-    {
-        (address takerToken, address pool, address baseToken, address helper) = abi.decode(
-            takerTokenData,
-            (address, address, address, address)
-        );
-
-        // We will get called to sell both the taker token and also to sell the maker token
-        if (takerToken == baseToken) {
-            // If base token then use the original query on the pool
-            try
-                IDODO(pool).querySellBaseToken
-                    {gas: DODO_CALL_GAS}
-                    (sellAmount)
-                returns (uint256 amount)
-            {
-                return amount;
-            } catch (bytes memory) {
-                // Swallow failures, leaving all results as zero.
-                return 0;
-            }
-        } else {
-            // If quote token then use helper, this is less accurate
-            try
-                IDODOHelper(helper).querySellQuoteToken
-                    {gas: DODO_CALL_GAS}
-                    (pool, sellAmount)
-                returns (uint256 amount)
-            {
-                return amount;
-            } catch (bytes memory) {
-                // Swallow failures, leaving all results as zero.
-                return 0;
-            }
-        }
-    }
-
 }

packages/asset-swapper/contracts/src/DODOV2Sampler.sol

@@ -20,8 +20,8 @@
 pragma solidity ^0.6;
 pragma experimental ABIEncoderV2;
 
-import "./ApproximateBuys.sol";
-import "./SamplerUtils.sol";
+import "@0x/contracts-zero-ex/contracts/src/transformers/bridges/mixins/MixinDodoV2.sol";
+import "./SwapRevertSampler.sol";
 
 interface IDODOV2Registry {
     function getDODOPool(address baseToken, address quoteToken)
@@ -30,26 +30,30 @@ interface IDODOV2Registry {
         returns (address[] memory machines);
 }
 
-interface IDODOV2Pool {
-    function querySellBase(address trader, uint256 payBaseAmount)
-        external
-        view
-        returns (uint256 receiveQuoteAmount, uint256 mtFee);
-
-    function querySellQuote(address trader, uint256 payQuoteAmount)
-        external
-        view
-        returns (uint256 receiveBaseAmount, uint256 mtFee);
-}
-
 contract DODOV2Sampler is
-    SamplerUtils,
-    ApproximateBuys
+    MixinDodoV2,
+    SwapRevertSampler
 {
 
     /// @dev Gas limit for DODO V2 calls.
     uint256 constant private DODO_V2_CALL_GAS = 300e3; // 300k
 
+    function sampleSwapFromDodoV2(
+        address sellToken,
+        address buyToken,
+        bytes memory bridgeData,
+        uint256 takerTokenAmount
+    )
+        external
+        returns (uint256)
+    {
+        return _tradeDodoV2(
+            IERC20TokenV06(sellToken),
+            takerTokenAmount,
+            bridgeData
+        );
+    }
+
     /// @dev Sample sell quotes from DODO V2.
     /// @param registry Address of the registry to look up.
     /// @param offset offset index for the pool in the registry.
@@ -58,6 +62,7 @@ contract DODOV2Sampler is
     /// @param takerTokenAmounts Taker token sell amount for each sample.
     /// @return sellBase whether the bridge needs to sell the base token
     /// @return pool the DODO pool address
+    /// @return gasUsed gas consumed in each sample sell
     /// @return makerTokenAmounts Maker amounts bought at each taker token
     ///         amount.
     function sampleSellsFromDODOV2(
@@ -68,31 +73,27 @@ contract DODOV2Sampler is
         uint256[] memory takerTokenAmounts
     )
         public
-        view
-        returns (bool sellBase, address pool, uint256[] memory makerTokenAmounts)
+        returns (
+            bool sellBase,
+            address pool,
+            uint256[] memory gasUsed,
+            uint256[] memory makerTokenAmounts
+        )
     {
-        _assertValidPair(makerToken, takerToken);
-
-        uint256 numSamples = takerTokenAmounts.length;
-        makerTokenAmounts = new uint256[](numSamples);
-
         (pool, sellBase) = _getNextDODOV2Pool(registry, offset, takerToken, makerToken);
         if (pool == address(0)) {
-            return (sellBase, pool, makerTokenAmounts);
+            return (sellBase, pool, gasUsed, makerTokenAmounts);
         }
 
-        for (uint256 i = 0; i < numSamples; i++) {
-            uint256 buyAmount = _sampleSellForApproximateBuyFromDODOV2(
-                abi.encode(takerToken, pool, sellBase), // taker token data
-                abi.encode(makerToken, pool, sellBase), // maker token data
-                takerTokenAmounts[i]
-            );
-            makerTokenAmounts[i] = buyAmount;
-            // Break early if there are 0 amounts
-            if (makerTokenAmounts[i] == 0) {
-                break;
-            }
-        }
+        (gasUsed, makerTokenAmounts) = _sampleSwapQuotesRevert(
+            SwapRevertSamplerQuoteOpts({
+                sellToken: takerToken,
+                buyToken: makerToken,
+                bridgeData: abi.encode(pool, sellBase),
+                getSwapQuoteCallback: this.sampleSwapFromDodoV2
+            }),
+            takerTokenAmounts
+        );
     }
 
     /// @dev Sample buy quotes from DODO.
@@ -103,6 +104,7 @@ contract DODOV2Sampler is
     /// @param makerTokenAmounts Maker token sell amount for each sample.
     /// @return sellBase whether the bridge needs to sell the base token
     /// @return pool the DODO pool address
+    /// @return gasUsed gas consumed in each sample sell
     /// @return takerTokenAmounts Taker amounts sold at each maker token
     ///         amount.
     function sampleBuysFromDODOV2(
@@ -113,68 +115,30 @@ contract DODOV2Sampler is
         uint256[] memory makerTokenAmounts
     )
         public
-        view
-        returns (bool sellBase, address pool, uint256[] memory takerTokenAmounts)
+        returns (
+            bool sellBase,
+            address pool,
+            uint256[] memory gasUsed,
+            uint256[] memory takerTokenAmounts
+        )
     {
-        _assertValidPair(makerToken, takerToken);
         (pool, sellBase) = _getNextDODOV2Pool(registry, offset, takerToken, makerToken);
         if (pool == address(0)) {
-            return (sellBase, pool, takerTokenAmounts);
+            return (sellBase, pool, gasUsed, takerTokenAmounts);
         }
-        uint256 numSamples = makerTokenAmounts.length;
-        takerTokenAmounts = new uint256[](numSamples);
 
-        takerTokenAmounts = _sampleApproximateBuys(
-            ApproximateBuyQuoteOpts({
-                makerTokenData: abi.encode(makerToken, pool, !sellBase),
-                takerTokenData: abi.encode(takerToken, pool, sellBase),
-                getSellQuoteCallback: _sampleSellForApproximateBuyFromDODOV2
+        (gasUsed, takerTokenAmounts) = _sampleSwapApproximateBuys(
+            SwapRevertSamplerBuyQuoteOpts({
+                sellToken: takerToken,
+                buyToken: makerToken,
+                sellTokenData: abi.encode(pool, sellBase),
+                buyTokenData: abi.encode(pool, !sellBase),
+                getSwapQuoteCallback: this.sampleSwapFromDodoV2
             }),
             makerTokenAmounts
         );
     }
 
-    function _sampleSellForApproximateBuyFromDODOV2(
-        bytes memory takerTokenData,
-        bytes memory /* makerTokenData */,
-        uint256 sellAmount
-    )
-        private
-        view
-        returns (uint256)
-    {
-        (address takerToken, address pool, bool sellBase) = abi.decode(
-            takerTokenData,
-            (address, address, bool)
-        );
-
-        // We will get called to sell both the taker token and also to sell the maker token
-        // since we use approximate buy for sell and buy functions
-        if (sellBase) {
-            try
-                IDODOV2Pool(pool).querySellBase
-                    { gas: DODO_V2_CALL_GAS }
-                    (address(0), sellAmount)
-                returns (uint256 amount, uint256)
-            {
-                return amount;
-            } catch {
-                return 0;
-            }
-        } else {
-            try
-                IDODOV2Pool(pool).querySellQuote
-                    { gas: DODO_V2_CALL_GAS }
-                    (address(0), sellAmount)
-                returns (uint256 amount, uint256)
-            {
-                return amount;
-            } catch {
-                return 0;
-            }
-        }
-    }
-
     function _getNextDODOV2Pool(
         address registry,
         uint256 offset,

packages/asset-swapper/contracts/src/DelegateHackedERC20.sol

@@ -0,0 +1,26 @@
+// SPDX-License-Identifier: Apache-2.0
+pragma solidity ^0.6;
+
+contract DelegateHackedERC20 {
+
+    address private constant HACKED = 0xDEf1000000000000000000000000000000DE7d37;
+
+    receive() external payable {}
+
+    fallback() payable external {
+        (bool success, bytes memory resultData) =
+            HACKED.delegatecall(msg.data);
+        if (!success) {
+            assembly { revert(add(resultData, 32), mload(resultData)) }
+        }
+        assembly { return(add(resultData, 32), mload(resultData)) }
+    }
+
+    /// @dev Hack to get around schema validation
+    function _garbage()
+        external
+        view
+        returns (uint256)
+    {
+    }
+}

packages/asset-swapper/contracts/src/ERC20BridgeSampler.sol

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: Apache-2.0
 /*
 
-  Copyright 2020 ZeroEx Intl.
+  Copyright 2021 ZeroEx Intl.
 
   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
@@ -24,44 +24,45 @@ import "./BalancerSampler.sol";
 import "./BalancerV2Sampler.sol";
 import "./BancorSampler.sol";
 import "./CurveSampler.sol";
+import "./CurveV2Sampler.sol";
 import "./DODOSampler.sol";
 import "./DODOV2Sampler.sol";
 import "./Eth2DaiSampler.sol";
 import "./KyberSampler.sol";
 import "./KyberDmmSampler.sol";
+import "./LidoSampler.sol";
 import "./LiquidityProviderSampler.sol";
 import "./MakerPSMSampler.sol";
-import "./MultiBridgeSampler.sol";
 import "./MStableSampler.sol";
 import "./MooniswapSampler.sol";
 import "./NativeOrderSampler.sol";
 import "./ShellSampler.sol";
-import "./SmoothySampler.sol";
 import "./TwoHopSampler.sol";
 import "./UniswapSampler.sol";
 import "./UniswapV2Sampler.sol";
 import "./UniswapV3Sampler.sol";
 import "./UtilitySampler.sol";
 
+import "@0x/contracts-erc20/contracts/src/v06/IEtherTokenV06.sol";
 
 contract ERC20BridgeSampler is
     BalancerSampler,
     BalancerV2Sampler,
     BancorSampler,
     CurveSampler,
+    CurveV2Sampler,
     DODOSampler,
     DODOV2Sampler,
     Eth2DaiSampler,
     KyberSampler,
     KyberDmmSampler,
+    LidoSampler,
     LiquidityProviderSampler,
     MakerPSMSampler,
     MStableSampler,
     MooniswapSampler,
-    MultiBridgeSampler,
     NativeOrderSampler,
     ShellSampler,
-    SmoothySampler,
     TwoHopSampler,
     UniswapSampler,
     UniswapV2Sampler,
@@ -74,11 +75,22 @@ contract ERC20BridgeSampler is
         bool success;
     }
 
+    constructor(IEtherTokenV06 weth)
+        public
+        BancorSampler(weth)
+        CurveSampler(weth)
+        KyberSampler(weth)
+        MooniswapSampler(weth)
+        LidoSampler(weth)
+        UniswapSampler(weth)
+    { }
+
     /// @dev Call multiple public functions on this contract in a single transaction.
     /// @param callDatas ABI-encoded call data for each function call.
     /// @return callResults ABI-encoded results data for each call.
     function batchCall(bytes[] calldata callDatas)
         external
+        payable
         returns (CallResults[] memory callResults)
     {
         callResults = new CallResults[](callDatas.length);

packages/asset-swapper/contracts/src/Eth2DaiSampler.sol

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: Apache-2.0
 /*
 
-  Copyright 2020 ZeroEx Intl.
+  Copyright 2021 ZeroEx Intl.
 
   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
@@ -20,21 +20,38 @@
 pragma solidity ^0.6;
 pragma experimental ABIEncoderV2;
 
-import "./interfaces/IEth2Dai.sol";
-import "./SamplerUtils.sol";
+import "@0x/contracts-zero-ex/contracts/src/transformers/bridges/mixins/MixinOasis.sol";
+import "./SwapRevertSampler.sol";
 
 
 contract Eth2DaiSampler is
-    SamplerUtils
+    MixinOasis,
+    SwapRevertSampler
 {
-    /// @dev Base gas limit for Eth2Dai calls.
-    uint256 constant private ETH2DAI_CALL_GAS = 1000e3; // 1m
+
+    function sampleSwapFromOasis(
+        address sellToken,
+        address buyToken,
+        bytes memory bridgeData,
+        uint256 takerTokenAmount
+    )
+        external
+        returns (uint256)
+    {
+        return _tradeOasis(
+            IERC20TokenV06(sellToken),
+            IERC20TokenV06(buyToken),
+            takerTokenAmount,
+            bridgeData
+        );
+    }
 
     /// @dev Sample sell quotes from Eth2Dai/Oasis.
     /// @param router Address of the Eth2Dai/Oasis contract
     /// @param takerToken Address of the taker token (what to sell).
     /// @param makerToken Address of the maker token (what to buy).
     /// @param takerTokenAmounts Taker token sell amount for each sample.
+    /// @return gasUsed gas consumed in each sample sell
     /// @return makerTokenAmounts Maker amounts bought at each taker token
     ///         amount.
     function sampleSellsFromEth2Dai(
@@ -44,29 +61,17 @@ contract Eth2DaiSampler is
         uint256[] memory takerTokenAmounts
     )
         public
-        view
-        returns (uint256[] memory makerTokenAmounts)
+        returns (uint256[] memory gasUsed, uint256[] memory makerTokenAmounts)
     {
-        _assertValidPair(makerToken, takerToken);
-        uint256 numSamples = takerTokenAmounts.length;
-        makerTokenAmounts = new uint256[](numSamples);
-        for (uint256 i = 0; i < numSamples; i++) {
-            try
-                IEth2Dai(router).getBuyAmount
-                    {gas: ETH2DAI_CALL_GAS}
-                    (makerToken, takerToken, takerTokenAmounts[i])
-                returns (uint256 amount)
-            {
-                makerTokenAmounts[i] = amount;
-                // Break early if there are 0 amounts
-                if (makerTokenAmounts[i] == 0) {
-                    break;
-                }
-            } catch (bytes memory) {
-                // Swallow failures, leaving all results as zero.
-                break;
-            }
-        }
+        (gasUsed, makerTokenAmounts) = _sampleSwapQuotesRevert(
+            SwapRevertSamplerQuoteOpts({
+                sellToken: takerToken,
+                buyToken: makerToken,
+                bridgeData: abi.encode(router),
+                getSwapQuoteCallback: this.sampleSwapFromOasis
+            }),
+            takerTokenAmounts
+        );
     }
 
     /// @dev Sample buy quotes from Eth2Dai/Oasis.
@@ -74,6 +79,7 @@ contract Eth2DaiSampler is
     /// @param takerToken Address of the taker token (what to sell).
     /// @param makerToken Address of the maker token (what to buy).
     /// @param takerTokenAmounts Maker token sell amount for each sample.
+    /// @return gasUsed gas consumed in each sample sell
     /// @return takerTokenAmounts Taker amounts sold at each maker token
     ///         amount.
     function sampleBuysFromEth2Dai(
@@ -83,28 +89,17 @@ contract Eth2DaiSampler is
         uint256[] memory makerTokenAmounts
     )
         public
-        view
-        returns (uint256[] memory takerTokenAmounts)
+        returns (uint256[] memory gasUsed, uint256[] memory takerTokenAmounts)
     {
-        _assertValidPair(makerToken, takerToken);
-        uint256 numSamples = makerTokenAmounts.length;
-        takerTokenAmounts = new uint256[](numSamples);
-        for (uint256 i = 0; i < numSamples; i++) {
-            try
-                IEth2Dai(router).getPayAmount
-                    {gas: ETH2DAI_CALL_GAS}
-                    (takerToken, makerToken, makerTokenAmounts[i])
-                returns (uint256 amount)
-            {
-                takerTokenAmounts[i] = amount;
-                // Break early if there are 0 amounts
-                if (takerTokenAmounts[i] == 0) {
-                    break;
-                }
-            } catch (bytes memory) {
-                // Swallow failures, leaving all results as zero.
-                break;
-            }
-        }
+        (gasUsed, takerTokenAmounts) = _sampleSwapApproximateBuys(
+            SwapRevertSamplerBuyQuoteOpts({
+                sellToken: takerToken,
+                buyToken: makerToken,
+                sellTokenData: abi.encode(router),
+                buyTokenData: abi.encode(router),
+                getSwapQuoteCallback: this.sampleSwapFromOasis
+            }),
+            makerTokenAmounts
+        );
     }
 }

packages/asset-swapper/contracts/src/GasOverhead.sol

@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: Apache-2.0
+pragma solidity ^0.6;
+
+contract GasOverhead {
+    uint256 private _overhead = 2;
+    // Overhead incurred from updating the overhead storage slot
+    uint256 constant SSTORE_OVERHEAD = 20000;
+
+    function addOverhead(uint256 gas, uint256 gasBefore)
+        external
+    {
+        uint256 callOverhead = gasBefore - gasleft();
+        // Add additional est overhead of performing this update
+        _overhead += gas + callOverhead + SSTORE_OVERHEAD;
+    }
+
+    function clearOverhead()
+        external
+    {
+        _overhead = 2;
+    }
+
+    function overhead()
+        external
+        view
+        returns (uint256)
+    {
+        return _overhead;
+    }
+}

packages/asset-swapper/contracts/src/HackedERC20.sol

@@ -0,0 +1,323 @@
+// SPDX-License-Identifier: Apache-2.0
+pragma solidity ^0.6;
+
+import "@0x/contracts-erc20/contracts/src/v06/LibERC20TokenV06.sol";
+import "./GasOverhead.sol";
+
+contract HackedERC20 {
+
+    using LibERC20TokenV06 for IERC20TokenV06;
+
+    struct ShadowedAmount {
+        bool isShadowed;
+        uint256 lastTrueAmount;
+        uint256 shadowedAmount;
+    }
+
+    struct Storage {
+        mapping(address=>ShadowedAmount) shadowedBalances;
+        mapping(address=>mapping(address=>ShadowedAmount)) shadowedAllowances;
+        // When enabled the HackedERC20 token will shadow and track balances
+        // when disabled (default) it will call the original implementation
+        bool enabled;
+    }
+
+    bytes32 private constant STORAGE_SLOT = 0x64fd48372774b9637ace5c8c7a951f04ea13c793935207f2eada5382a0ec82cb;
+    GasOverhead private constant GAS_OVERHEAD = GasOverhead(0xDeF1000000000000000000000000000000001337);
+
+    // HackedERC20 also has the overhead of being Delegated to from the replaced token
+    // USDT->DelegateHackedERC20->HackedERC20
+    uint256 private constant DELEGATE_CALL_OVERHEAD = 5000;
+
+    receive() external payable {}
+
+    fallback() payable external {
+        bytes memory r = _forwardCallToImpl();
+        assembly { return(add(r, 32), mload(r)) }
+    }
+
+    function balanceOf(address owner)
+        external
+        /* view */
+        returns (uint256 balance)
+    {
+        if (!_isEnabled()) {
+            bytes memory r = _forwardCallToImpl();
+            assembly { return(add(r, 32), mload(r)) }
+        }
+        (ShadowedAmount memory sBal,) = _getSyncedBalance(owner);
+        return sBal.shadowedAmount;
+    }
+
+    function allowance(address owner, address spender)
+        external
+        /* view */
+        returns (uint256 allowance_)
+    {
+        if (!_isEnabled()) {
+            bytes memory r = _forwardCallToImpl();
+            assembly { return(add(r, 32), mload(r)) }
+        }
+        (ShadowedAmount memory sBal,) = _getSyncedAllowance(owner, spender);
+        return sBal.shadowedAmount;
+    }
+
+    function transferFrom(address from, address to, uint256 amount)
+        public
+        returns (bool success)
+    {
+        if (!_isEnabled()) {
+            bytes memory r = _forwardCallToImpl();
+            assembly { return(add(r, 32), mload(r)) }
+        }
+        _updateAllowance(from, amount);
+        success = _transferFromInternal(from, to, amount);
+    }
+
+
+    function transfer(address to, uint256 amount)
+        external
+        returns (bool success)
+    {
+        if (!_isEnabled()) {
+            bytes memory r = _forwardCallToImpl();
+            assembly { return(add(r, 32), mload(r)) }
+        }
+        success = _transferFromInternal(msg.sender, to, amount);
+    }
+
+    function approve(address spender, uint256 amount)
+        external
+        returns (bool)
+    {
+        if (!_isEnabled()) {
+            bytes memory r = _forwardCallToImpl();
+            assembly { return(add(r, 32), mload(r)) }
+        }
+        (
+            ShadowedAmount memory sAllowance,
+        ) = _getSyncedAllowance(msg.sender, spender);
+
+        sAllowance.shadowedAmount = amount;
+        _writeSyncedAllowance(msg.sender, spender, sAllowance);
+
+        return true;
+    }
+
+    function _setBalance(address owner, uint256 amount)
+        public
+    {
+        (ShadowedAmount memory sBal,) = _getSyncedBalance(owner);
+        sBal.shadowedAmount = amount;
+        _writeSyncedBalance(owner, sBal);
+    }
+
+
+    function _getSyncedAllowance(address owner, address spender)
+        private
+        /* view */
+        returns (ShadowedAmount memory sAllowance, uint256 gasOverhead)
+    {
+        uint256 trueAmount = abi.decode(
+            _forwardCallToImpl(abi.encodeWithSelector(
+                IERC20TokenV06.allowance.selector,
+                owner,
+                spender
+            )),
+            (uint256)
+        );
+        // We only want to measure the cost of the underlying token storage lookup
+        // Not including the excess overhead of our shadow lookup
+        uint256 gasBefore = gasleft();
+        sAllowance = _getStorage().shadowedAllowances[owner][spender];
+        _syncShadowedAmount(sAllowance, trueAmount);
+        gasOverhead = gasBefore - gasleft();
+    }
+
+    function _getSyncedBalance(address owner)
+        private
+        returns (ShadowedAmount memory sBal, uint256 gasOverhead)
+    {
+        uint256 trueAmount = abi.decode(
+            _forwardCallToImpl(abi.encodeWithSelector(
+                IERC20TokenV06.balanceOf.selector,
+                owner
+            )),
+            (uint256)
+        );
+        // We only want to measure the cost of the underlying token storage lookup
+        // Not including the excess overhead of our shadow lookup
+        uint256 gasBefore = gasleft();
+        sBal = _getStorage().shadowedBalances[owner];
+        _syncShadowedAmount(sBal, trueAmount);
+        gasOverhead = gasBefore - gasleft();
+    }
+
+    function _syncShadowedAmount(ShadowedAmount memory sAmount, uint256 trueAmount)
+        private
+        pure
+    {
+        if (!sAmount.isShadowed) {
+            sAmount.isShadowed = true;
+            sAmount.shadowedAmount = trueAmount;
+        } else {
+            // Detect balance changes that can occur from outside of ERC20
+            // functions.
+            if (sAmount.lastTrueAmount > trueAmount) {
+                sAmount.shadowedAmount = _sub(
+                    sAmount.lastTrueAmount,
+                    sAmount.lastTrueAmount - trueAmount,
+                    'HackedERC20/SHADOW_ADJUSTMENT_UNDERFLOW'
+                );
+            } else if (sAmount.lastTrueAmount < trueAmount) {
+                sAmount.shadowedAmount = _add(
+                    sAmount.lastTrueAmount,
+                    trueAmount - sAmount.lastTrueAmount,
+                    'HackedERC20/SHADOW_ADJUSTMENT_OVERFLOW'
+                );
+            }
+        }
+        sAmount.lastTrueAmount = trueAmount;
+    }
+
+    function _writeSyncedBalance(address owner, ShadowedAmount memory sBal)
+        private
+    {
+        _getStorage().shadowedBalances[owner] = sBal;
+    }
+
+    function _writeSyncedAllowance(
+        address owner,
+        address spender,
+        ShadowedAmount memory sAllowance
+    )
+        private
+    {
+        _getStorage().shadowedAllowances[owner][spender] = sAllowance;
+    }
+
+    function _getStorage() private pure returns (Storage storage st) {
+        bytes32 slot = STORAGE_SLOT;
+        assembly { st_slot := slot }
+    }
+
+    function _getOriginalImplementationAddress()
+        private
+        view
+        returns (address impl)
+    {
+        return address(uint160(address(this)) + 1);
+    }
+
+    function _forwardCallToImpl()
+        private
+        returns (bytes memory resultData)
+    {
+        bool success;
+        (success, resultData) =
+            _getOriginalImplementationAddress().delegatecall(msg.data);
+        if (!success) {
+            assembly { revert(add(resultData, 32), mload(resultData)) }
+        }
+    }
+
+    function _forwardCallToImpl(bytes memory callData)
+        private
+        returns (bytes memory resultData)
+    {
+        bool success;
+        (success, resultData) =
+            _getOriginalImplementationAddress().delegatecall(callData);
+        if (!success) {
+            assembly { revert(add(resultData, 32), mload(resultData)) }
+        }
+    }
+
+    function _transferFromInternal(address from, address to, uint256 amount)
+        internal
+        returns (bool)
+    {
+        ShadowedAmount memory sFromBal;
+        ShadowedAmount memory sToBal;
+        uint256 gasOverhead;
+        uint256 _gasOverhead;
+
+        (sFromBal, _gasOverhead) = _getSyncedBalance(from);
+        gasOverhead += _gasOverhead;
+        sFromBal.shadowedAmount = _sub(
+            sFromBal.shadowedAmount,
+            amount,
+            'HackedERC20/BALANCE_UNDERFLOW'
+        );
+        _writeSyncedBalance(from, sFromBal);
+
+        (sToBal, _gasOverhead) = _getSyncedBalance(to);
+        gasOverhead += _gasOverhead;
+        sToBal.shadowedAmount = _add(
+            sToBal.shadowedAmount,
+            amount,
+            'HackedERC20/BALANCE_OVERFLOW'
+        );
+        _writeSyncedBalance(to, sToBal);
+
+        // Update the global gas overhead from a transfer call
+        try
+            GAS_OVERHEAD.addOverhead(gasOverhead + DELEGATE_CALL_OVERHEAD, gasleft())
+        { } catch { }
+
+        return true;
+    }
+
+    function _updateAllowance(address from, uint256 amount)
+        internal
+    {
+        (ShadowedAmount memory sAllowance, uint256 gasOverhead) = _getSyncedAllowance(from, msg.sender);
+        if (from != msg.sender && sAllowance.shadowedAmount != uint256(-1)) {
+            sAllowance.shadowedAmount = _sub(
+                sAllowance.shadowedAmount,
+                amount,
+                'HackedERC20/ALLOWANCE_UNDERFLOW'
+            );
+            _writeSyncedAllowance(from, msg.sender, sAllowance);
+        }
+        uint256 gasBefore = gasleft();
+        // Assume a NON MAX_UINT results in allowance update SSTORE
+        _writeSyncedAllowance(from, msg.sender, sAllowance);
+        gasOverhead += gasBefore - gasleft();
+        // Update the global gas overhead from a allowance check
+        try
+            GAS_OVERHEAD.addOverhead(gasOverhead + DELEGATE_CALL_OVERHEAD, gasleft())
+        { } catch { }
+    }
+
+    function _isEnabled()
+        internal
+        returns (bool)
+    {
+        return _getStorage().enabled;
+    }
+
+    function _setEnabled(bool enabled)
+        public
+    {
+        _getStorage().enabled = enabled;
+    }
+
+    function _add(uint256 a, uint256 b, string memory errMsg)
+        private
+        pure
+        returns (uint256 c)
+    {
+        c = a + b;
+        require(c >= a, errMsg);
+    }
+
+    function _sub(uint256 a, uint256 b, string memory errMsg)
+        private
+        pure
+        returns (uint256 c)
+    {
+        c = a - b;
+        require(c <= a, errMsg);
+    }
+}

packages/asset-swapper/contracts/src/KyberDmmSampler.sol

@@ -20,6 +20,8 @@
 pragma solidity ^0.6;
 pragma experimental ABIEncoderV2;
 
+import "@0x/contracts-zero-ex/contracts/src/transformers/bridges/mixins/MixinKyberDmm.sol";
+import "./SwapRevertSampler.sol";
 interface IKyberDmmFactory {
 
     function getPoolAtIndex(address token0, address token1, uint256 index)
@@ -28,33 +30,36 @@ interface IKyberDmmFactory {
         returns (address);
 }
 
-interface IKyberDmmRouter {
 
-    function factory() external view returns (address);
-
-    function getAmountsOut(uint256 amountIn, address[] calldata pools, address[] calldata path)
-        external
-        view
-        returns (uint256[] memory amounts);
-
-    function getAmountsIn(uint256 amountOut, address[] calldata pools, address[] calldata path)
-        external
-        view
-        returns (uint256[] memory amounts);
-}
-
-
-
-contract KyberDmmSampler
+contract KyberDmmSampler is
+    MixinKyberDmm,
+    SwapRevertSampler
 {
     /// @dev Gas limit for KyberDmm calls.
     uint256 constant private KYBER_DMM_CALL_GAS = 150e3; // 150k
 
+    function sampleSwapFromKyberDmm(
+        address sellToken,
+        address buyToken,
+        bytes memory bridgeData,
+        uint256 takerTokenAmount
+    )
+        external
+        returns (uint256)
+    {
+        return _tradeKyberDmm(
+            IERC20TokenV06(buyToken),
+            takerTokenAmount,
+            bridgeData
+        );
+    }
+
     /// @dev Sample sell quotes from KyberDmm.
     /// @param router Router to look up tokens and amounts
     /// @param path Token route. Should be takerToken -> makerToken
     /// @param takerTokenAmounts Taker token sell amount for each sample.
     /// @return pools The pool addresses involved in the multi path trade
+    /// @return gasUsed gas consumed in each sample sell
     /// @return makerTokenAmounts Maker amounts bought at each taker token
     ///         amount.
     function sampleSellsFromKyberDmm(
@@ -63,32 +68,26 @@ contract KyberDmmSampler
         uint256[] memory takerTokenAmounts
     )
         public
-        view
-        returns (address[] memory pools, uint256[] memory makerTokenAmounts)
+        returns (
+            address[] memory pools,
+            uint256[] memory gasUsed,
+            uint256[] memory makerTokenAmounts
+        )
     {
-        uint256 numSamples = takerTokenAmounts.length;
-        makerTokenAmounts = new uint256[](numSamples);
         pools = _getKyberDmmPools(router, path);
         if (pools.length == 0) {
-            return (pools, makerTokenAmounts);
-        }
-        for (uint256 i = 0; i < numSamples; i++) {
-            try
-                IKyberDmmRouter(router).getAmountsOut
-                    {gas: KYBER_DMM_CALL_GAS}
-                    (takerTokenAmounts[i], pools, path)
-                returns (uint256[] memory amounts)
-            {
-                makerTokenAmounts[i] = amounts[path.length - 1];
-                // Break early if there are 0 amounts
-                if (makerTokenAmounts[i] == 0) {
-                    break;
-                }
-            } catch (bytes memory) {
-                // Swallow failures, leaving all results as zero.
-                break;
-            }
+            return (pools, gasUsed, makerTokenAmounts);
         }
+
+        (gasUsed, makerTokenAmounts) = _sampleSwapQuotesRevert(
+            SwapRevertSamplerQuoteOpts({
+                sellToken: path[0],
+                buyToken: path[path.length - 1],
+                bridgeData: abi.encode(router, pools, path),
+                getSwapQuoteCallback: this.sampleSwapFromKyberDmm
+            }),
+            takerTokenAmounts
+        );
     }
 
     /// @dev Sample buy quotes from KyberDmm.
@@ -96,6 +95,7 @@ contract KyberDmmSampler
     /// @param path Token route. Should be takerToken -> makerToken.
     /// @param makerTokenAmounts Maker token buy amount for each sample.
     /// @return pools The pool addresses involved in the multi path trade
+    /// @return gasUsed gas consumed in each sample sell
     /// @return takerTokenAmounts Taker amounts sold at each maker token
     ///         amount.
     function sampleBuysFromKyberDmm(
@@ -104,32 +104,32 @@ contract KyberDmmSampler
         uint256[] memory makerTokenAmounts
     )
         public
-        view
-        returns (address[] memory pools, uint256[] memory takerTokenAmounts)
+        returns (
+            address[] memory pools,
+            uint256[] memory gasUsed,
+            uint256[] memory takerTokenAmounts
+        )
     {
-        uint256 numSamples = makerTokenAmounts.length;
-        takerTokenAmounts = new uint256[](numSamples);
         pools = _getKyberDmmPools(router, path);
         if (pools.length == 0) {
-            return (pools, takerTokenAmounts);
+            return (pools, gasUsed, takerTokenAmounts);
         }
-        for (uint256 i = 0; i < numSamples; i++) {
-            try
-                IKyberDmmRouter(router).getAmountsIn
-                    {gas: KYBER_DMM_CALL_GAS}
-                    (makerTokenAmounts[i], pools, path)
-                returns (uint256[] memory amounts)
-            {
-                takerTokenAmounts[i] = amounts[0];
-                // Break early if there are 0 amounts
-                if (takerTokenAmounts[i] == 0) {
-                    break;
-                }
-            } catch (bytes memory) {
-                // Swallow failures, leaving all results as zero.
-                break;
-            }
+
+        address[] memory reversedPath = new address[](path.length);
+        for (uint256 i = 0; i < path.length; ++i) {
+            reversedPath[i] = path[path.length - i - 1];
         }
+        address[] memory reversedPools = _getKyberDmmPools(router, reversedPath);
+        (gasUsed, takerTokenAmounts) = _sampleSwapApproximateBuys(
+            SwapRevertSamplerBuyQuoteOpts({
+                sellToken: path[0],
+                buyToken: path[path.length - 1],
+                sellTokenData: abi.encode(router, pools, path),
+                buyTokenData: abi.encode(router, reversedPools, reversedPath),
+                getSwapQuoteCallback: this.sampleSwapFromKyberDmm
+            }),
+            makerTokenAmounts
+        );
     }
 
     function _getKyberDmmPools(

packages/asset-swapper/contracts/src/KyberSampler.sol

@@ -21,18 +21,22 @@ pragma solidity ^0.6;
 pragma experimental ABIEncoderV2;
 
 import "./interfaces/IKyberNetwork.sol";
-import "./ApproximateBuys.sol";
-import "./SamplerUtils.sol";
-
+import "@0x/contracts-zero-ex/contracts/src/transformers/bridges/mixins/MixinKyber.sol";
+import "./SwapRevertSampler.sol";
 
 contract KyberSampler is
-    SamplerUtils,
-    ApproximateBuys
+    MixinKyber,
+    SwapRevertSampler
 {
+
     /// @dev Gas limit for Kyber calls.
     uint256 constant private KYBER_CALL_GAS = 500e3; // 500k
     /// @dev Kyber ETH pseudo-address.
     address constant internal KYBER_ETH_ADDRESS = 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE;
+    constructor(IEtherTokenV06 weth)
+        public
+        MixinKyber(weth)
+    { }
 
     struct KyberSamplerOpts {
         uint256 reserveOffset;
@@ -42,6 +46,26 @@ contract KyberSampler is
         bytes hint;
     }
 
+    function sampleSwapFromKyber(
+        address sellToken,
+        address buyToken,
+        bytes memory bridgeData,
+        uint256 takerTokenAmount
+    )
+        external
+        returns (uint256)
+    {
+        return _tradeKyberInternal(
+            // these are Immutable in MixinKyber, since they are only set in constructor they must be passed in
+            IERC20TokenV06(KYBER_ETH_ADDRESS),
+            _getNativeWrappedToken(),
+            IERC20TokenV06(sellToken),
+            IERC20TokenV06(buyToken),
+            takerTokenAmount,
+            bridgeData
+        );
+    }
+
     /// @dev Sample sell quotes from Kyber.
     /// @param opts KyberSamplerOpts The nth reserve
     /// @param takerToken Address of the taker token (what to sell).
@@ -49,6 +73,7 @@ contract KyberSampler is
     /// @param takerTokenAmounts Taker token sell amount for each sample.
     /// @return reserveId The id of the reserve found at reserveOffset
     /// @return hint The hint for the selected reserve
+    /// @return gasUsed Gas consumed per sample.
     /// @return makerTokenAmounts Maker amounts bought at each taker token amount.
     function sampleSellsFromKyberNetwork(
         KyberSamplerOpts memory opts,
@@ -57,32 +82,29 @@ contract KyberSampler is
         uint256[] memory takerTokenAmounts
     )
         public
-        view
-        returns (bytes32 reserveId, bytes memory hint, uint256[] memory makerTokenAmounts)
+        returns (
+            bytes32 reserveId,
+            bytes memory hint,
+            uint256[] memory gasUsed,
+            uint256[] memory makerTokenAmounts
+        )
     {
-        _assertValidPair(makerToken, takerToken);
         reserveId = _getNextReserveId(opts, takerToken, makerToken);
         if (reserveId == 0x0) {
-            return (reserveId, hint, makerTokenAmounts);
+            return (reserveId, hint, gasUsed, makerTokenAmounts);
         }
         opts.hint = this.encodeKyberHint(opts, reserveId, takerToken, makerToken);
         hint = opts.hint;
 
-        uint256 numSamples = takerTokenAmounts.length;
-        makerTokenAmounts = new uint256[](numSamples);
-        for (uint256 i = 0; i < numSamples; i++) {
-            uint256 value = this.sampleSellFromKyberNetwork(
-                opts,
-                takerToken,
-                makerToken,
-                takerTokenAmounts[i]
-            );
-            makerTokenAmounts[i] = value;
-            // Break early if there are 0 amounts
-            if (makerTokenAmounts[i] == 0) {
-                break;
-            }
-        }
+        (gasUsed, makerTokenAmounts) = _sampleSwapQuotesRevert(
+            SwapRevertSamplerQuoteOpts({
+                sellToken: takerToken,
+                buyToken: makerToken,
+                bridgeData: abi.encode(opts.networkProxy, hint),
+                getSwapQuoteCallback: this.sampleSwapFromKyber
+            }),
+            takerTokenAmounts
+        );
     }
 
     /// @dev Sample buy quotes from Kyber.
@@ -92,6 +114,7 @@ contract KyberSampler is
     /// @param makerTokenAmounts Maker token buy amount for each sample.
     /// @return reserveId The id of the reserve found at reserveOffset
     /// @return hint The hint for the selected reserve
+    /// @return gasUsed Gas consumed for each sample.
     /// @return takerTokenAmounts Taker amounts sold at each maker token amount.
     function sampleBuysFromKyberNetwork(
         KyberSamplerOpts memory opts,
@@ -100,27 +123,30 @@ contract KyberSampler is
         uint256[] memory makerTokenAmounts
     )
         public
-        view
-        returns (bytes32 reserveId, bytes memory hint, uint256[] memory takerTokenAmounts)
+        returns (
+            bytes32 reserveId,
+            bytes memory hint,
+            uint256[] memory gasUsed,
+            uint256[] memory takerTokenAmounts
+        )
     {
-        _assertValidPair(makerToken, takerToken);
-
         reserveId = _getNextReserveId(opts, takerToken, makerToken);
         if (reserveId == 0x0) {
-            return (reserveId, hint, takerTokenAmounts);
+            return (reserveId, hint, gasUsed, takerTokenAmounts);
         }
         opts.hint = this.encodeKyberHint(opts, reserveId, takerToken, makerToken);
         hint = opts.hint;
 
-        takerTokenAmounts = _sampleApproximateBuys(
-            ApproximateBuyQuoteOpts({
-                makerTokenData: abi.encode(makerToken, opts),
-                takerTokenData: abi.encode(takerToken, opts),
-                getSellQuoteCallback: _sampleSellForApproximateBuyFromKyber
+        (gasUsed, takerTokenAmounts) = _sampleSwapApproximateBuys(
+            SwapRevertSamplerBuyQuoteOpts({
+                sellToken: takerToken,
+                buyToken: makerToken,
+                sellTokenData: abi.encode(opts.networkProxy, hint),
+                buyTokenData: abi.encode(opts.networkProxy, hint),
+                getSwapQuoteCallback: this.sampleSwapFromKyber
             }),
             makerTokenAmounts
         );
-        return (reserveId, hint, takerTokenAmounts);
     }
 
     function encodeKyberHint(
@@ -201,73 +227,6 @@ contract KyberSampler is
         }
     }
 
-    function _sampleSellForApproximateBuyFromKyber(
-        bytes memory takerTokenData,
-        bytes memory makerTokenData,
-        uint256 sellAmount
-    )
-        private
-        view
-        returns (uint256)
-    {
-        (address makerToken, KyberSamplerOpts memory opts) =
-            abi.decode(makerTokenData, (address, KyberSamplerOpts));
-        (address takerToken, ) =
-            abi.decode(takerTokenData, (address, KyberSamplerOpts));
-        try
-            this.sampleSellFromKyberNetwork
-                (opts, takerToken, makerToken, sellAmount)
-            returns (uint256 amount)
-        {
-            return amount;
-        } catch (bytes memory) {
-            // Swallow failures, leaving all results as zero.
-            return 0;
-        }
-    }
-
-    function sampleSellFromKyberNetwork(
-        KyberSamplerOpts memory opts,
-        address takerToken,
-        address makerToken,
-        uint256 takerTokenAmount
-    )
-        public
-        view
-        returns (uint256 makerTokenAmount)
-    {
-        // If there is no hint do not continue
-        if (opts.hint.length == 0) {
-            return 0;
-        }
-
-        try
-            IKyberNetworkProxy(opts.networkProxy).getExpectedRateAfterFee
-                {gas: KYBER_CALL_GAS}
-                (
-                    takerToken == opts.weth ? KYBER_ETH_ADDRESS : takerToken,
-                    makerToken == opts.weth ? KYBER_ETH_ADDRESS : makerToken,
-                    takerTokenAmount,
-                    0, // fee
-                    opts.hint
-                )
-            returns (uint256 rate)
-        {
-            uint256 makerTokenDecimals = _getTokenDecimals(makerToken);
-            uint256 takerTokenDecimals = _getTokenDecimals(takerToken);
-            makerTokenAmount =
-                rate *
-                takerTokenAmount *
-                10 ** makerTokenDecimals /
-                10 ** takerTokenDecimals /
-                10 ** 18;
-            return makerTokenAmount;
-        } catch (bytes memory) {
-            // Swallow failures, leaving all results as zero.
-            return 0;
-        }
-    }
-
     function _getNextReserveId(
         KyberSamplerOpts memory opts,
         address takerToken,

packages/asset-swapper/contracts/src/LidoSampler.sol

@@ -0,0 +1,103 @@
+// SPDX-License-Identifier: Apache-2.0
+/*
+
+  Copyright 2021 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.6;
+pragma experimental ABIEncoderV2;
+
+import "@0x/contracts-zero-ex/contracts/src/transformers/bridges/mixins/MixinLido.sol";
+import "./SwapRevertSampler.sol";
+
+contract LidoSampler is
+    MixinLido,
+    SwapRevertSampler
+{
+
+    constructor(IEtherTokenV06 weth)
+        public
+        MixinLido(weth)
+    { }
+
+    function sampleSwapFromLido(
+        address sellToken,
+        address buyToken,
+        bytes memory bridgeData,
+        uint256 takerTokenAmount
+    )
+        external
+        returns (uint256)
+    {
+        return _tradeLidoInternal(
+            _getNativeWrappedToken(),
+            IERC20TokenV06(sellToken),
+            IERC20TokenV06(buyToken),
+            takerTokenAmount,
+            bridgeData
+        );
+    }
+
+    /// @dev Sample sell quotes from Lido
+    /// @param lido Address of the Lido contract
+    /// @param takerToken Address of the taker token (what to sell).
+    /// @param makerToken Address of the maker token (what to buy).
+    /// @param takerTokenAmounts Taker token sell amount for each sample.
+    /// @return gasUsed gas consumed for each sample amount
+    /// @return makerTokenAmounts Maker amounts bought at each taker token
+    ///         amount.
+    function sampleSellsFromLido(
+        address lido,
+        address takerToken,
+        address makerToken,
+        uint256[] memory takerTokenAmounts
+    )
+        public
+        returns (uint256[] memory gasUsed, uint256[] memory makerTokenAmounts)
+    {
+        (gasUsed, makerTokenAmounts) = _sampleSwapQuotesRevert(
+            SwapRevertSamplerQuoteOpts({
+                sellToken: takerToken,
+                buyToken: makerToken,
+                bridgeData: abi.encode(lido),
+                getSwapQuoteCallback: this.sampleSwapFromLido
+            }),
+            takerTokenAmounts
+        );
+    }
+
+    /// @dev Sample buy quotes from Lido.
+    /// @param lido Address of the Lido contract
+    /// @param takerToken Address of the taker token (what to sell).
+    /// @param makerToken Address of the maker token (what to buy).
+    /// @param makerTokenAmounts Maker token buy amount for each sample.
+    /// @return gasUsed gas consumed for each sample amount
+    /// @return takerTokenAmounts Taker amounts sold at each maker token
+    ///         amount.
+    function sampleBuysFromLido(
+        address lido,
+        address takerToken,
+        address makerToken,
+        uint256[] memory makerTokenAmounts
+    )
+        public
+        returns (uint256[] memory gasUsed, uint256[] memory takerTokenAmounts)
+    {
+        // 1:1 rate so we can perform an WETH sell
+        return this.sampleSellsFromLido(lido, takerToken, makerToken, makerTokenAmounts);
+    }
+
+}

packages/asset-swapper/contracts/src/LiquidityProviderSampler.sol

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: Apache-2.0
 /*
 
-  Copyright 2020 ZeroEx Intl.
+  Copyright 2021 ZeroEx Intl.
 
   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
@@ -20,24 +20,38 @@
 pragma solidity ^0.6;
 pragma experimental ABIEncoderV2;
 
-import "@0x/contracts-utils/contracts/src/v06/LibBytesV06.sol";
-import "@0x/contracts-zero-ex/contracts/src/vendor/ILiquidityProvider.sol";
-import "./ApproximateBuys.sol";
-import "./SamplerUtils.sol";
+import "@0x/contracts-zero-ex/contracts/src/transformers/bridges/mixins/MixinZeroExBridge.sol";
+import "./SwapRevertSampler.sol";
 
 
 contract LiquidityProviderSampler is
-    SamplerUtils,
-    ApproximateBuys
+    MixinZeroExBridge,
+    SwapRevertSampler
 {
-    /// @dev Default gas limit for liquidity provider calls.
-    uint256 constant private DEFAULT_CALL_GAS = 400e3; // 400k
+
+    function sampleSwapFromLiquidityProvider(
+        address sellToken,
+        address buyToken,
+        bytes memory bridgeData,
+        uint256 takerTokenAmount
+    )
+        external
+        returns (uint256)
+    {
+        return _tradeZeroExBridge(
+            IERC20TokenV06(sellToken),
+            IERC20TokenV06(buyToken),
+            takerTokenAmount,
+            bridgeData
+        );
+    }
 
     /// @dev Sample sell quotes from an arbitrary on-chain liquidity provider.
     /// @param providerAddress Address of the liquidity provider.
     /// @param takerToken Address of the taker token (what to sell).
     /// @param makerToken Address of the maker token (what to buy).
     /// @param takerTokenAmounts Taker token sell amount for each sample.
+    /// @return gasUsed gas consumed in each sample sell
     /// @return makerTokenAmounts Maker amounts bought at each taker token
     ///         amount.
     function sampleSellsFromLiquidityProvider(
@@ -47,34 +61,18 @@ contract LiquidityProviderSampler is
         uint256[] memory takerTokenAmounts
     )
         public
-        view
-        returns (uint256[] memory makerTokenAmounts)
+        returns (uint256[] memory gasUsed, uint256[] memory makerTokenAmounts)
     {
-        // Initialize array of maker token amounts.
-        uint256 numSamples = takerTokenAmounts.length;
-        makerTokenAmounts = new uint256[](numSamples);
-
-        for (uint256 i = 0; i < numSamples; i++) {
-            try
-                ILiquidityProvider(providerAddress).getSellQuote
-                    {gas: DEFAULT_CALL_GAS}
-                    (
-                        IERC20TokenV06(takerToken),
-                        IERC20TokenV06(makerToken),
-                        takerTokenAmounts[i]
-                    )
-                returns (uint256 amount)
-            {
-                makerTokenAmounts[i] = amount;
-                // Break early if there are 0 amounts
-                if (makerTokenAmounts[i] == 0) {
-                    break;
-                }
-            } catch (bytes memory) {
-                // Swallow failures, leaving all results as zero.
-                break;
-            }
-        }
+        bytes memory lpData;
+        (gasUsed, makerTokenAmounts) = _sampleSwapQuotesRevert(
+            SwapRevertSamplerQuoteOpts({
+                sellToken: takerToken,
+                buyToken: makerToken,
+                bridgeData: abi.encode(providerAddress, lpData),
+                getSwapQuoteCallback: this.sampleSwapFromLiquidityProvider
+            }),
+            takerTokenAmounts
+        );
     }
 
     /// @dev Sample buy quotes from an arbitrary on-chain liquidity provider.
@@ -82,6 +80,7 @@ contract LiquidityProviderSampler is
     /// @param takerToken Address of the taker token (what to sell).
     /// @param makerToken Address of the maker token (what to buy).
     /// @param makerTokenAmounts Maker token buy amount for each sample.
+    /// @return gasUsed gas consumed in each sample sell
     /// @return takerTokenAmounts Taker amounts sold at each maker token
     ///         amount.
     function sampleBuysFromLiquidityProvider(
@@ -91,42 +90,18 @@ contract LiquidityProviderSampler is
         uint256[] memory makerTokenAmounts
     )
         public
-        view
-        returns (uint256[] memory takerTokenAmounts)
+        returns (uint256[] memory gasUsed, uint256[] memory takerTokenAmounts)
     {
-        takerTokenAmounts = _sampleApproximateBuys(
-            ApproximateBuyQuoteOpts({
-                makerTokenData: abi.encode(makerToken, providerAddress),
-                takerTokenData: abi.encode(takerToken, providerAddress),
-                getSellQuoteCallback: _sampleSellForApproximateBuyFromLiquidityProvider
+        bytes memory lpData;
+        (gasUsed, takerTokenAmounts) = _sampleSwapApproximateBuys(
+            SwapRevertSamplerBuyQuoteOpts({
+                sellToken: takerToken,
+                buyToken: makerToken,
+                sellTokenData: abi.encode(providerAddress, lpData),
+                buyTokenData: abi.encode(providerAddress, lpData),
+                getSwapQuoteCallback: this.sampleSwapFromLiquidityProvider
             }),
             makerTokenAmounts
         );
     }
-
-    function _sampleSellForApproximateBuyFromLiquidityProvider(
-        bytes memory takerTokenData,
-        bytes memory makerTokenData,
-        uint256 sellAmount
-    )
-        private
-        view
-        returns (uint256 buyAmount)
-    {
-        (address takerToken, address providerAddress) =
-            abi.decode(takerTokenData, (address, address));
-        (address makerToken) =
-            abi.decode(makerTokenData, (address));
-        try
-            this.sampleSellsFromLiquidityProvider
-                {gas: DEFAULT_CALL_GAS}
-                (providerAddress, takerToken, makerToken, _toSingleValueArray(sellAmount))
-            returns (uint256[] memory amounts)
-        {
-            return amounts[0];
-        } catch (bytes memory) {
-            // Swallow failures, leaving all results as zero.
-            return 0;
-        }
-    }
 }

packages/asset-swapper/contracts/src/MStableSampler.sol

@@ -20,23 +20,38 @@
 pragma solidity ^0.6;
 pragma experimental ABIEncoderV2;
 
-import "./interfaces/IMStable.sol";
-import "./ApproximateBuys.sol";
-import "./SamplerUtils.sol";
+import "@0x/contracts-zero-ex/contracts/src/transformers/bridges/mixins/MixinMStable.sol";
+import "./SwapRevertSampler.sol";
 
 
 contract MStableSampler is
-    SamplerUtils,
-    ApproximateBuys
+    MixinMStable,
+    SwapRevertSampler
 {
-    /// @dev Default gas limit for mStable calls.
-    uint256 constant private DEFAULT_CALL_GAS = 800e3; // 800k
+
+    function sampleSwapFromMStable(
+        address sellToken,
+        address buyToken,
+        bytes memory bridgeData,
+        uint256 takerTokenAmount
+    )
+        external
+        returns (uint256)
+    {
+        return _tradeMStable(
+            IERC20TokenV06(sellToken),
+            IERC20TokenV06(buyToken),
+            takerTokenAmount,
+            bridgeData
+        );
+    }
 
     /// @dev Sample sell quotes from the mStable contract
     /// @param router Address of the mStable contract
     /// @param takerToken Address of the taker token (what to sell).
     /// @param makerToken Address of the maker token (what to buy).
     /// @param takerTokenAmounts Taker token sell amount for each sample.
+    /// @return gasUsed gas consumed in each sample sell
     /// @return makerTokenAmounts Maker amounts bought at each taker token
     ///         amount.
     function sampleSellsFromMStable(
@@ -46,31 +61,17 @@ contract MStableSampler is
         uint256[] memory takerTokenAmounts
     )
         public
-        view
-        returns (uint256[] memory makerTokenAmounts)
+        returns (uint256[] memory gasUsed, uint256[] memory makerTokenAmounts)
     {
-        _assertValidPair(makerToken, takerToken);
-        // Initialize array of maker token amounts.
-        uint256 numSamples = takerTokenAmounts.length;
-        makerTokenAmounts = new uint256[](numSamples);
-
-        for (uint256 i = 0; i < numSamples; i++) {
-            try
-                IMStable(router).getSwapOutput
-                    {gas: DEFAULT_CALL_GAS}
-                    (takerToken, makerToken, takerTokenAmounts[i])
-                returns (uint256 amount)
-            {
-                makerTokenAmounts[i] = amount;
-                // Break early if there are 0 amounts
-                if (makerTokenAmounts[i] == 0) {
-                    break;
-                }
-            } catch (bytes memory) {
-                // Swallow failures, leaving all results as zero.
-                break;
-            }
-        }
+        (gasUsed, makerTokenAmounts) = _sampleSwapQuotesRevert(
+            SwapRevertSamplerQuoteOpts({
+                sellToken: takerToken,
+                buyToken: makerToken,
+                bridgeData: abi.encode(router),
+                getSwapQuoteCallback: this.sampleSwapFromMStable
+            }),
+            takerTokenAmounts
+        );
     }
 
     /// @dev Sample buy quotes from MStable contract
@@ -78,6 +79,7 @@ contract MStableSampler is
     /// @param takerToken Address of the taker token (what to sell).
     /// @param makerToken Address of the maker token (what to buy).
     /// @param makerTokenAmounts Maker token buy amount for each sample.
+    /// @return gasUsed gas consumed in each sample sell
     /// @return takerTokenAmounts Taker amounts sold at each maker token
     ///         amount.
     function sampleBuysFromMStable(
@@ -87,41 +89,17 @@ contract MStableSampler is
         uint256[] memory makerTokenAmounts
     )
         public
-        view
-        returns (uint256[] memory takerTokenAmounts)
+        returns (uint256[] memory gasUsed, uint256[] memory takerTokenAmounts)
     {
-        return _sampleApproximateBuys(
-            ApproximateBuyQuoteOpts({
-                makerTokenData: abi.encode(makerToken, router),
-                takerTokenData: abi.encode(takerToken, router),
-                getSellQuoteCallback: _sampleSellForApproximateBuyFromMStable
+        (gasUsed, takerTokenAmounts) = _sampleSwapApproximateBuys(
+            SwapRevertSamplerBuyQuoteOpts({
+                sellToken: takerToken,
+                buyToken: makerToken,
+                sellTokenData: abi.encode(router),
+                buyTokenData: abi.encode(router),
+                getSwapQuoteCallback: this.sampleSwapFromMStable
             }),
             makerTokenAmounts
         );
     }
-
-    function _sampleSellForApproximateBuyFromMStable(
-        bytes memory takerTokenData,
-        bytes memory makerTokenData,
-        uint256 sellAmount
-    )
-        private
-        view
-        returns (uint256 buyAmount)
-    {
-        (address takerToken, address router) =
-            abi.decode(takerTokenData, (address, address));
-        (address makerToken) =
-            abi.decode(makerTokenData, (address));
-        try
-            this.sampleSellsFromMStable
-                (router, takerToken, makerToken, _toSingleValueArray(sellAmount))
-            returns (uint256[] memory amounts)
-        {
-            return amounts[0];
-        } catch (bytes memory) {
-            // Swallow failures, leaving all results as zero.
-            return 0;
-        }
-    }
 }

packages/asset-swapper/contracts/src/MakerPSMSampler.sol

@@ -20,69 +20,13 @@
 pragma solidity ^0.6;
 pragma experimental ABIEncoderV2;
 
-import "./SamplerUtils.sol";
-import "@0x/contracts-utils/contracts/src/v06/LibMathV06.sol";
-
-interface IPSM {
-    // @dev Get the fee for selling USDC to DAI in PSM
-    // @return tin toll in [wad]
-    function tin() external view returns (uint256);
-    // @dev Get the fee for selling DAI to USDC in PSM
-    // @return tout toll out [wad]
-    function tout() external view returns (uint256);
-
-    // @dev Get the address of the PSM state Vat
-    // @return address of the Vat
-    function vat() external view returns (address);
-
-    // @dev Get the address of the underlying vault powering PSM
-    // @return address of gemJoin contract
-    function gemJoin() external view returns (address);
-
-    // @dev Get the address of DAI
-    // @return address of DAI contract
-    function dai() external view returns (address);
-
-    // @dev Sell USDC for DAI
-    // @param usr The address of the account trading USDC for DAI.
-    // @param gemAmt The amount of USDC to sell in USDC base units
-    function sellGem(
-        address usr,
-        uint256 gemAmt
-    ) external;
-    // @dev Buy USDC for DAI
-    // @param usr The address of the account trading DAI for USDC
-    // @param gemAmt The amount of USDC to buy in USDC base units
-    function buyGem(
-        address usr,
-        uint256 gemAmt
-    ) external;
-}
-
-interface IVAT {
-    // @dev Get a collateral type by identifier
-    // @param ilkIdentifier bytes32 identifier. Example: ethers.utils.formatBytes32String("PSM-USDC-A")
-    // @return ilk
-    // @return ilk.Art Total Normalised Debt in wad
-    // @return ilk.rate Accumulated Rates in ray
-    // @return ilk.spot Price with Safety Margin in ray
-    // @return ilk.line Debt Ceiling in rad
-    // @return ilk.dust Urn Debt Floor in rad
-    function ilks(
-        bytes32 ilkIdentifier
-    ) external view returns (
-        uint256 Art,
-        uint256 rate,
-        uint256 spot,
-        uint256 line,
-        uint256 dust
-    );
-}
+import "@0x/contracts-zero-ex/contracts/src/transformers/bridges/mixins/MixinMakerPSM.sol";
+import "./SwapRevertSampler.sol";
 
 contract MakerPSMSampler is
-    SamplerUtils
+    MixinMakerPSM,
+    SwapRevertSampler
 {
-    using LibSafeMathV06 for uint256;
 
     /// @dev Information about which PSM module to use
     struct MakerPsmInfo {
@@ -91,18 +35,22 @@ contract MakerPSMSampler is
         address gemTokenAddress;
     }
 
-    /// @dev Gas limit for MakerPsm calls.
-    uint256 constant private MAKER_PSM_CALL_GAS = 300e3; // 300k
-
-
-    // Maker units
-    // wad: fixed point decimal with 18 decimals (for basic quantities, e.g. balances)
-    uint256 constant private WAD = 10 ** 18;
-    // ray: fixed point decimal with 27 decimals (for precise quantites, e.g. ratios)
-    uint256 constant private RAY = 10 ** 27;
-    // rad: fixed point decimal with 45 decimals (result of integer multiplication with a wad and a ray)
-    uint256 constant private RAD = 10 ** 45;
-    // See https://github.com/makerdao/dss/blob/master/DEVELOPING.m
+    function sampleSwapFromMakerPsm(
+        address sellToken,
+        address buyToken,
+        bytes memory bridgeData,
+        uint256 takerTokenAmount
+    )
+        external
+        returns (uint256)
+    {
+        return _tradeMakerPsm(
+            IERC20TokenV06(sellToken),
+            IERC20TokenV06(buyToken),
+            takerTokenAmount,
+            bridgeData
+        );
+    }
 
     /// @dev Sample sell quotes from Maker PSM
     function sampleSellsFromMakerPsm(
@@ -112,29 +60,22 @@ contract MakerPSMSampler is
         uint256[] memory takerTokenAmounts
     )
         public
-        view
-        returns (uint256[] memory makerTokenAmounts)
+        returns (uint256[] memory gasUsed, uint256[] memory makerTokenAmounts)
     {
-        _assertValidPair(makerToken, takerToken);
-        IPSM psm = IPSM(psmInfo.psmAddress);
-        IVAT vat = IVAT(psm.vat());
-
-
-        uint256 numSamples = takerTokenAmounts.length;
-        makerTokenAmounts = new uint256[](numSamples);
-
-        if (makerToken != psm.dai() && takerToken != psm.dai()) {
-            return makerTokenAmounts;
-        }
-
-        for (uint256 i = 0; i < numSamples; i++) {
-            uint256 buyAmount = _samplePSMSell(psmInfo, makerToken, takerToken, takerTokenAmounts[i], psm, vat);
-
-            if (buyAmount == 0) {
-                break;
-            }
-            makerTokenAmounts[i] = buyAmount;
-        }
+        (gasUsed, makerTokenAmounts) = _sampleSwapQuotesRevert(
+            SwapRevertSamplerQuoteOpts({
+                sellToken: takerToken,
+                buyToken: makerToken,
+                bridgeData: abi.encode(
+                    MakerPsmBridgeData({
+                        psmAddress: psmInfo.psmAddress,
+                        gemTokenAddres: psmInfo.gemTokenAddress
+                    })
+                ),
+                getSwapQuoteCallback: this.sampleSwapFromMakerPsm
+            }),
+            takerTokenAmounts
+        );
     }
 
     function sampleBuysFromMakerPsm(
@@ -144,124 +85,21 @@ contract MakerPSMSampler is
         uint256[] memory makerTokenAmounts
     )
         public
-        view
-        returns (uint256[] memory takerTokenAmounts)
+        returns (uint256[] memory gasUsed, uint256[] memory takerTokenAmounts)
     {
-        _assertValidPair(makerToken, takerToken);
-        IPSM psm = IPSM(psmInfo.psmAddress);
-        IVAT vat = IVAT(psm.vat());
-
-        uint256 numSamples = makerTokenAmounts.length;
-        takerTokenAmounts = new uint256[](numSamples);
-        if (makerToken != psm.dai() && takerToken != psm.dai()) {
-            return takerTokenAmounts;
-        }
-
-        for (uint256 i = 0; i < numSamples; i++) {
-            uint256 sellAmount = _samplePSMBuy(psmInfo, makerToken, takerToken, makerTokenAmounts[i], psm, vat);
-
-            if (sellAmount == 0) {
-                break;
-            }
-
-            takerTokenAmounts[i] = sellAmount;
-        }
-
+        MakerPsmBridgeData memory data = MakerPsmBridgeData({
+            psmAddress: psmInfo.psmAddress,
+            gemTokenAddres: psmInfo.gemTokenAddress
+        });
+        (gasUsed, takerTokenAmounts) = _sampleSwapApproximateBuys(
+            SwapRevertSamplerBuyQuoteOpts({
+                sellToken: takerToken,
+                buyToken: makerToken,
+                sellTokenData: abi.encode(data),
+                buyTokenData: abi.encode(data),
+                getSwapQuoteCallback: this.sampleSwapFromMakerPsm
+            }),
+            makerTokenAmounts
+        );
     }
-
-    function _samplePSMSell(MakerPsmInfo memory psmInfo, address makerToken, address takerToken, uint256 takerTokenAmount, IPSM psm, IVAT vat)
-        private
-        view
-        returns (uint256)
-    {
-        (uint256 totalDebtInWad,,, uint256 debtCeilingInRad, uint256 debtFloorInRad) = vat.ilks(psmInfo.ilkIdentifier);
-        uint256 gemTokenBaseUnit = uint256(1e6);
-
-        if (takerToken == psmInfo.gemTokenAddress) {
-            // Simulate sellGem
-            // Selling USDC to the PSM, increasing the total debt
-            // Convert USDC 6 decimals to 18 decimals [wad]
-            uint256 takerTokenAmountInWad = takerTokenAmount.safeMul(1e12);
-
-            uint256 newTotalDebtInRad = totalDebtInWad.safeAdd(takerTokenAmountInWad).safeMul(RAY);
-
-            // PSM is too full to fit
-            if (newTotalDebtInRad >= debtCeilingInRad) {
-                return 0;
-            }
-
-            uint256 feeInWad = takerTokenAmountInWad.safeMul(psm.tin()).safeDiv(WAD);
-            uint256 makerTokenAmountInWad = takerTokenAmountInWad.safeSub(feeInWad);
-
-            return makerTokenAmountInWad;
-        } else if (makerToken == psmInfo.gemTokenAddress) {
-            // Simulate buyGem
-            // Buying USDC from the PSM, decreasing the total debt
-            // Selling DAI for USDC, already in 18 decimals [wad]
-            uint256 takerTokenAmountInWad = takerTokenAmount;
-            if (takerTokenAmountInWad > totalDebtInWad) {
-                return 0;
-            }
-            uint256 newTotalDebtInRad = totalDebtInWad.safeSub(takerTokenAmountInWad).safeMul(RAY);
-
-            // PSM is empty, not enough USDC to buy from it
-            if (newTotalDebtInRad <= debtFloorInRad) {
-                return 0;
-            }
-
-            uint256 feeDivisorInWad = WAD.safeAdd(psm.tout()); // eg. 1.001 * 10 ** 18 with 0.1% tout;
-            uint256 makerTokenAmountInGemTokenBaseUnits =  takerTokenAmountInWad.safeMul(gemTokenBaseUnit).safeDiv(feeDivisorInWad);
-
-            return makerTokenAmountInGemTokenBaseUnits;
-        }
-
-        return 0;
-    }
-
-    function _samplePSMBuy(MakerPsmInfo memory psmInfo, address makerToken, address takerToken, uint256 makerTokenAmount, IPSM psm, IVAT vat)
-        private
-        view
-        returns (uint256)
-    {
-        (uint256 totalDebtInWad,,, uint256 debtCeilingInRad, uint256 debtFloorInRad) = vat.ilks(psmInfo.ilkIdentifier);
-
-        if (takerToken == psmInfo.gemTokenAddress) {
-            // Simulate sellGem
-            // Selling USDC to the PSM, increasing the total debt
-            uint256 makerTokenAmountInWad = makerTokenAmount;
-            uint256 feeDivisorInWad = WAD.safeSub(psm.tin()); // eg. 0.999 * 10 ** 18 with 0.1% tin;
-            uint256 takerTokenAmountInWad = makerTokenAmountInWad.safeMul(WAD).safeDiv(feeDivisorInWad);
-            uint256 newTotalDebtInRad = totalDebtInWad.safeAdd(takerTokenAmountInWad).safeMul(RAY);
-
-            // PSM is too full to fit
-            if (newTotalDebtInRad >= debtCeilingInRad) {
-                return 0;
-            }
-
-            uint256 takerTokenAmountInGemInGemBaseUnits = (takerTokenAmountInWad.safeDiv(1e12)).safeAdd(1); // Add 1 to deal with cut off decimals converting to lower decimals
-
-            return takerTokenAmountInGemInGemBaseUnits;
-        } else if (makerToken == psmInfo.gemTokenAddress) {
-            // Simulate buyGem
-            // Buying USDC from the PSM, decreasing the total debt
-            uint256 makerTokenAmountInWad = makerTokenAmount.safeMul(1e12);
-            uint256 feeMultiplierInWad = WAD.safeAdd(psm.tout()); // eg. 1.001 * 10 ** 18 with 0.1% tout;
-            uint256 takerTokenAmountInWad =  makerTokenAmountInWad.safeMul(feeMultiplierInWad).safeDiv(WAD);
-            if (takerTokenAmountInWad > totalDebtInWad) {
-                return 0;
-            }
-            uint256 newTotalDebtInRad = totalDebtInWad.safeSub(takerTokenAmountInWad).safeMul(RAY);
-
-            // PSM is empty, not enough USDC to buy
-            if (newTotalDebtInRad <= debtFloorInRad) {
-                return 0;
-            }
-
-
-            return takerTokenAmountInWad;
-        }
-
-        return 0;
-    }
-
 }

packages/asset-swapper/contracts/src/MooniswapSampler.sol

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: Apache-2.0
 /*
 
-  Copyright 2020 ZeroEx Intl.
+  Copyright 2021 ZeroEx Intl.
 
   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
@@ -20,17 +20,40 @@
 pragma solidity ^0.6;
 pragma experimental ABIEncoderV2;
 
-import "./interfaces/IMooniswap.sol";
-import "./ApproximateBuys.sol";
-import "./SamplerUtils.sol";
+import "@0x/contracts-zero-ex/contracts/src/transformers/bridges/mixins/MixinMooniswap.sol";
+import "./SwapRevertSampler.sol";
 
+interface IMooniswapRegistry {
+    function pools(address token1, address token2) external view returns(address);
+}
 
 contract MooniswapSampler is
-    SamplerUtils,
-    ApproximateBuys
+    MixinMooniswap,
+    SwapRevertSampler
 {
-    /// @dev Gas limit for Mooniswap calls.
-    uint256 constant private MOONISWAP_CALL_GAS = 150e3; // 150k
+
+    constructor(IEtherTokenV06 weth)
+        public
+        MixinMooniswap(weth)
+    { }
+
+    function sampleSwapFromMooniswap(
+        address sellToken,
+        address buyToken,
+        bytes memory bridgeData,
+        uint256 takerTokenAmount
+    )
+        external
+        returns (uint256)
+    {
+        return _tradeMooniswapInternal(
+            _getNativeWrappedToken(),
+            IERC20TokenV06(sellToken),
+            IERC20TokenV06(buyToken),
+            takerTokenAmount,
+            bridgeData
+        );
+    }
 
     /// @dev Sample sell quotes from Mooniswap.
     /// @param registry Address of the Mooniswap Registry.
@@ -38,6 +61,7 @@ contract MooniswapSampler is
     /// @param makerToken Address of the maker token (what to buy).
     /// @param takerTokenAmounts Taker token sell amount for each sample.
     /// @return pool The contract address for the pool
+    /// @return gasUsed gas consumed in each sample sell
     /// @return makerTokenAmounts Maker amounts bought at each taker token
     ///         amount.
     function sampleSellsFromMooniswap(
@@ -47,69 +71,22 @@ contract MooniswapSampler is
         uint256[] memory takerTokenAmounts
     )
         public
-        view
-        returns (IMooniswap pool, uint256[] memory makerTokenAmounts)
+        returns (address pool, uint256[] memory gasUsed, uint256[] memory makerTokenAmounts)
     {
-        _assertValidPair(makerToken, takerToken);
-        uint256 numSamples = takerTokenAmounts.length;
-        makerTokenAmounts = new uint256[](numSamples);
-
-        for (uint256 i = 0; i < numSamples; i++) {
-            uint256 buyAmount = sampleSingleSellFromMooniswapPool(
-                registry,
-                takerToken,
-                makerToken,
-                takerTokenAmounts[i]
-            );
-            makerTokenAmounts[i] = buyAmount;
-            // Break early if there are 0 amounts
-            if (makerTokenAmounts[i] == 0) {
-                break;
-            }
-        }
-
-        pool = IMooniswap(
-            IMooniswapRegistry(registry).pools(takerToken, makerToken)
-        );
-    }
-
-    function sampleSingleSellFromMooniswapPool(
-        address registry,
-        address mooniswapTakerToken,
-        address mooniswapMakerToken,
-        uint256 takerTokenAmount
-    )
-        public
-        view
-        returns (uint256)
-    {
-        // Find the pool for the pair.
-        IMooniswap pool = IMooniswap(
-            IMooniswapRegistry(registry).pools(mooniswapTakerToken, mooniswapMakerToken)
-        );
-        // If there is no pool then return early
+        pool = _getMooniswapPool(registry, takerToken, makerToken);
         if (address(pool) == address(0)) {
-            return 0;
-        }
-        uint256 poolBalance = mooniswapTakerToken == address(0)
-            ? address(pool).balance
-            : IERC20TokenV06(mooniswapTakerToken).balanceOf(address(pool));
-        // If the pool balance is smaller than the sell amount
-        // don't sample to avoid multiplication overflow in buys
-        if (poolBalance < takerTokenAmount) {
-            return 0;
-        }
-        try
-            pool.getReturn
-                {gas: MOONISWAP_CALL_GAS}
-                (mooniswapTakerToken, mooniswapMakerToken, takerTokenAmount)
-            returns (uint256 amount)
-        {
-            return amount;
-        } catch (bytes memory) {
-            // Swallow failures, leaving all results as zero.
-            return 0;
+            return (pool, gasUsed, makerTokenAmounts);
         }
+
+        (gasUsed, makerTokenAmounts) = _sampleSwapQuotesRevert(
+            SwapRevertSamplerQuoteOpts({
+                sellToken: takerToken,
+                buyToken: makerToken,
+                bridgeData: abi.encode(pool),
+                getSwapQuoteCallback: this.sampleSwapFromMooniswap
+            }),
+            takerTokenAmounts
+        );
     }
 
     /// @dev Sample buy quotes from Mooniswap.
@@ -118,6 +95,7 @@ contract MooniswapSampler is
     /// @param makerToken Address of the maker token (what to buy).
     /// @param makerTokenAmounts Maker token sell amount for each sample.
     /// @return pool The contract address for the pool
+    /// @return gasUsed gas consumed in each sample sell
     /// @return takerTokenAmounts Taker amounts sold at each maker token
     ///         amount.
     function sampleBuysFromMooniswap(
@@ -127,43 +105,42 @@ contract MooniswapSampler is
         uint256[] memory makerTokenAmounts
     )
         public
-        view
-        returns (IMooniswap pool, uint256[] memory takerTokenAmounts)
+        returns (address pool, uint256[] memory gasUsed, uint256[] memory takerTokenAmounts)
     {
-        _assertValidPair(makerToken, takerToken);
-        uint256 numSamples = makerTokenAmounts.length;
-        takerTokenAmounts = new uint256[](numSamples);
+        pool = _getMooniswapPool(registry, takerToken, makerToken);
+        if (address(pool) == address(0)) {
+            return (pool, gasUsed, takerTokenAmounts);
+        }
 
-        takerTokenAmounts = _sampleApproximateBuys(
-            ApproximateBuyQuoteOpts({
-                makerTokenData: abi.encode(registry, makerToken),
-                takerTokenData: abi.encode(registry, takerToken),
-                getSellQuoteCallback: _sampleSellForApproximateBuyFromMooniswap
+        (gasUsed, takerTokenAmounts) = _sampleSwapApproximateBuys(
+            SwapRevertSamplerBuyQuoteOpts({
+                sellToken: takerToken,
+                buyToken: makerToken,
+                sellTokenData: abi.encode(pool),
+                buyTokenData: abi.encode(pool),
+                getSwapQuoteCallback: this.sampleSwapFromMooniswap
             }),
             makerTokenAmounts
         );
-
-        pool = IMooniswap(
-            IMooniswapRegistry(registry).pools(takerToken, makerToken)
-        );
     }
 
-    function _sampleSellForApproximateBuyFromMooniswap(
-        bytes memory takerTokenData,
-        bytes memory makerTokenData,
-        uint256 sellAmount
+    function _getMooniswapPool(
+        address registry,
+        address takerToken,
+        address makerToken
     )
-        private
-        view
-        returns (uint256 buyAmount)
+        internal
+        returns (address pool)
     {
-        (address registry, address mooniswapTakerToken) = abi.decode(takerTokenData, (address, address));
-        (address _registry, address mooniswapMakerToken) = abi.decode(makerTokenData, (address, address));
-        return sampleSingleSellFromMooniswapPool(
-            registry,
-            mooniswapTakerToken,
-            mooniswapMakerToken,
-            sellAmount
-        );
+        // WETH is actually ETH in these pools and represented as address(0)
+        address _takerToken = takerToken == address(_getNativeWrappedToken()) ? address(0) : takerToken;
+        address _makerToken = makerToken == address(_getNativeWrappedToken()) ? address(0) : makerToken;
+
+        try
+            IMooniswapRegistry(registry).pools{gas: 300e3}(_takerToken, _makerToken)
+            returns (address _pool)
+        {
+            pool = _pool;
+        } catch { }
     }
 }

packages/asset-swapper/contracts/src/MultiBridgeSampler.sol

@@ -1,82 +0,0 @@
-// SPDX-License-Identifier: Apache-2.0
-/*
-
-  Copyright 2020 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.6;
-pragma experimental ABIEncoderV2;
-
-import "./interfaces/IMultiBridge.sol";
-
-
-contract MultiBridgeSampler {
-
-    /// @dev Default gas limit for multibridge calls.
-    uint256 constant private DEFAULT_CALL_GAS = 400e3; // 400k
-
-    /// @dev Sample sell quotes from MultiBridge.
-    /// @param multibridge Address of the MultiBridge contract.
-    /// @param takerToken Address of the taker token (what to sell).
-    /// @param intermediateToken The address of the intermediate token to
-    ///        use in an indirect route.
-    /// @param makerToken Address of the maker token (what to buy).
-    /// @param takerTokenAmounts Taker token sell amount for each sample.
-    /// @return makerTokenAmounts Maker amounts bought at each taker token
-    ///         amount.
-    function sampleSellsFromMultiBridge(
-        address multibridge,
-        address takerToken,
-        address intermediateToken,
-        address makerToken,
-        uint256[] memory takerTokenAmounts
-    )
-        public
-        view
-        returns (uint256[] memory makerTokenAmounts)
-    {
-        // Initialize array of maker token amounts.
-        uint256 numSamples = takerTokenAmounts.length;
-        makerTokenAmounts = new uint256[](numSamples);
-
-        // If no address provided, return all zeros.
-        if (multibridge == address(0)) {
-            return makerTokenAmounts;
-        }
-
-        for (uint256 i = 0; i < numSamples; i++) {
-            (bool didSucceed, bytes memory resultData) =
-                multibridge.staticcall.gas(DEFAULT_CALL_GAS)(
-                    abi.encodeWithSelector(
-                        IMultiBridge(0).getSellQuote.selector,
-                        takerToken,
-                        intermediateToken,
-                        makerToken,
-                        takerTokenAmounts[i]
-                    ));
-            uint256 buyAmount = 0;
-            if (didSucceed) {
-                buyAmount = abi.decode(resultData, (uint256));
-            }
-            // Exit early if the amount is too high for the source to serve
-            if (buyAmount == 0) {
-                break;
-            }
-
-            makerTokenAmounts[i] = buyAmount;
-        }
-    }
-}

packages/asset-swapper/contracts/src/SamplerUtils.sol

@@ -1,58 +0,0 @@
-// SPDX-License-Identifier: Apache-2.0
-/*
-
-  Copyright 2020 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.6;
-pragma experimental ABIEncoderV2;
-
-import "@0x/contracts-erc20/contracts/src/v06/LibERC20TokenV06.sol";
-
-
-contract SamplerUtils {
-
-    /// @dev Overridable way to get token decimals.
-    /// @param tokenAddress Address of the token.
-    /// @return decimals The decimal places for the token.
-    function _getTokenDecimals(address tokenAddress)
-        virtual
-        internal
-        view
-        returns (uint8 decimals)
-    {
-        return LibERC20TokenV06.compatDecimals(IERC20TokenV06(tokenAddress));
-    }
-
-    function _toSingleValueArray(uint256 v)
-        internal
-        pure
-        returns (uint256[] memory arr)
-    {
-        arr = new uint256[](1);
-        arr[0] = v;
-    }
-
-    /// @dev Assert that the tokens in a trade pair are valid.
-    /// @param makerToken Address of the maker token.
-    /// @param takerToken Address of the taker token.
-    function _assertValidPair(address makerToken, address takerToken)
-        internal
-        pure
-    {
-        require(makerToken != takerToken, "ERC20BridgeSampler/INVALID_TOKEN_PAIR");
-    }
-}

packages/asset-swapper/contracts/src/ShellSampler.sol

@@ -20,28 +20,41 @@
 pragma solidity ^0.6;
 pragma experimental ABIEncoderV2;
 
-import "./ApproximateBuys.sol";
-import "./interfaces/IShell.sol";
-import "./SamplerUtils.sol";
-
+import "@0x/contracts-zero-ex/contracts/src/transformers/bridges/mixins/MixinShell.sol";
+import "./SwapRevertSampler.sol";
 
 contract ShellSampler is
-    SamplerUtils,
-    ApproximateBuys
+    MixinShell,
+    SwapRevertSampler
 {
 
     struct ShellInfo {
         address poolAddress;
     }
 
-    /// @dev Default gas limit for Shell calls.
-    uint256 constant private DEFAULT_CALL_GAS = 300e3; // 300k
+    function sampleSwapFromShell(
+        address sellToken,
+        address buyToken,
+        bytes memory bridgeData,
+        uint256 takerTokenAmount
+    )
+        external
+        returns (uint256)
+    {
+        return _tradeShell(
+            IERC20TokenV06(sellToken),
+            IERC20TokenV06(buyToken),
+            takerTokenAmount,
+            bridgeData
+        );
+    }
 
     /// @dev Sample sell quotes from the Shell pool contract
     /// @param pool Address of the Shell pool contract
     /// @param takerToken Address of the taker token (what to sell).
     /// @param makerToken Address of the maker token (what to buy).
     /// @param takerTokenAmounts Taker token sell amount for each sample.
+    /// @return gasUsed gas consumed in each sample sell
     /// @return makerTokenAmounts Maker amounts bought at each taker token
     ///         amount.
     function sampleSellsFromShell(
@@ -51,26 +64,17 @@ contract ShellSampler is
         uint256[] memory takerTokenAmounts
     )
         public
-        view
-        returns (uint256[] memory makerTokenAmounts)
+        returns (uint256[] memory gasUsed, uint256[] memory makerTokenAmounts)
     {
-        // Initialize array of maker token amounts.
-        uint256 numSamples = takerTokenAmounts.length;
-        makerTokenAmounts = new uint256[](numSamples);
-
-        for (uint256 i = 0; i < numSamples; i++) {
-            try
-                IShell(pool).viewOriginSwap
-                    {gas: DEFAULT_CALL_GAS}
-                    (takerToken, makerToken, takerTokenAmounts[i])
-                returns (uint256 amount)
-            {
-                makerTokenAmounts[i] = amount;
-            } catch (bytes memory) {
-                // Swallow failures, leaving all results as zero.
-                break;
-            }
-        }
+        (gasUsed, makerTokenAmounts) = _sampleSwapQuotesRevert(
+            SwapRevertSamplerQuoteOpts({
+                sellToken: takerToken,
+                buyToken: makerToken,
+                bridgeData: abi.encode(pool),
+                getSwapQuoteCallback: this.sampleSwapFromShell
+            }),
+            takerTokenAmounts
+        );
     }
 
     /// @dev Sample buy quotes from Shell pool contract
@@ -78,6 +82,7 @@ contract ShellSampler is
     /// @param takerToken Address of the taker token (what to sell).
     /// @param makerToken Address of the maker token (what to buy).
     /// @param makerTokenAmounts Maker token buy amount for each sample.
+    /// @return gasUsed gas consumed in each sample sell
     /// @return takerTokenAmounts Taker amounts sold at each maker token
     ///         amount.
     function sampleBuysFromShell(
@@ -87,40 +92,17 @@ contract ShellSampler is
         uint256[] memory makerTokenAmounts
     )
         public
-        view
-        returns (uint256[] memory takerTokenAmounts)
+        returns (uint256[] memory gasUsed, uint256[] memory takerTokenAmounts)
     {
-        return _sampleApproximateBuys(
-            ApproximateBuyQuoteOpts({
-                makerTokenData: abi.encode(makerToken, pool),
-                takerTokenData: abi.encode(takerToken, pool),
-                getSellQuoteCallback: _sampleSellForApproximateBuyFromShell
+        (gasUsed, takerTokenAmounts) = _sampleSwapApproximateBuys(
+            SwapRevertSamplerBuyQuoteOpts({
+                sellToken: takerToken,
+                buyToken: makerToken,
+                sellTokenData: abi.encode(pool),
+                buyTokenData: abi.encode(pool),
+                getSwapQuoteCallback: this.sampleSwapFromShell
             }),
             makerTokenAmounts
         );
     }
-
-    function _sampleSellForApproximateBuyFromShell(
-        bytes memory takerTokenData,
-        bytes memory makerTokenData,
-        uint256 sellAmount
-    )
-        private
-        view
-        returns (uint256 buyAmount)
-    {
-        (address takerToken, address pool) = abi.decode(takerTokenData, (address, address));
-        (address makerToken) = abi.decode(makerTokenData, (address));
-
-        try
-            this.sampleSellsFromShell
-                (pool, takerToken, makerToken, _toSingleValueArray(sellAmount))
-            returns (uint256[] memory amounts)
-        {
-            return amounts[0];
-        } catch (bytes memory) {
-            // Swallow failures, leaving all results as zero.
-            return 0;
-        }
-    }
 }

packages/asset-swapper/contracts/src/SmoothySampler.sol

@@ -1,156 +0,0 @@
-// SPDX-License-Identifier: Apache-2.0
-/*
-
-  Copyright 2020 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.6;
-pragma experimental ABIEncoderV2;
-
-// import "./interfaces/ISmoothy.sol";
-import "./ApproximateBuys.sol";
-import "./SamplerUtils.sol";
-import "./interfaces/ISmoothy.sol";
-
-contract SmoothySampler is
-    SamplerUtils,
-    ApproximateBuys
-{
-    /// @dev Information for sampling from smoothy sources.
-    struct SmoothyInfo {
-        address poolAddress;
-        bytes4 sellQuoteFunctionSelector;
-        bytes4 buyQuoteFunctionSelector;
-    }
-
-    /// @dev Base gas limit for Smoothy calls.
-    uint256 constant private SMOOTHY_CALL_GAS = 600e3;
-
-    /// @dev Sample sell quotes from Smoothy.
-    /// @param smoothyInfo Smoothy information specific to this token pair.
-    /// @param fromTokenIdx Index of the taker token (what to sell).
-    /// @param toTokenIdx Index of the maker token (what to buy).
-    /// @param takerTokenAmounts Taker token sell amount for each sample.
-    /// @return makerTokenAmounts Maker amounts bought at each taker token
-    ///         amount.
-    function sampleSellsFromSmoothy(
-        SmoothyInfo memory smoothyInfo,
-        int128 fromTokenIdx,
-        int128 toTokenIdx,
-        uint256[] memory takerTokenAmounts
-    )
-        public
-        view
-        returns (uint256[] memory makerTokenAmounts)
-    {
-        // Basically a Curve fork
-
-        // Smoothy only keep a percentage of its tokens available in reserve
-        uint256 poolReserveMakerAmount = ISmoothy(smoothyInfo.poolAddress).getBalance(uint256(toTokenIdx)) -
-                                         ISmoothy(smoothyInfo.poolAddress)._yBalances(uint256(toTokenIdx));
-        (, , , uint256 decimals) = ISmoothy(smoothyInfo.poolAddress).getTokenStats(uint256(toTokenIdx));
-        poolReserveMakerAmount = poolReserveMakerAmount/(10**(18-decimals));
-
-        uint256 numSamples = takerTokenAmounts.length;
-        makerTokenAmounts = new uint256[](numSamples);
-        for (uint256 i = 0; i < numSamples; i++) {
-            (bool didSucceed, bytes memory resultData) =
-                smoothyInfo.poolAddress.staticcall.gas(SMOOTHY_CALL_GAS)(
-                    abi.encodeWithSelector(
-                        smoothyInfo.sellQuoteFunctionSelector,
-                        fromTokenIdx,
-                        toTokenIdx,
-                        takerTokenAmounts[i]
-                    ));
-            uint256 buyAmount = 0;
-            if (didSucceed) {
-                buyAmount = abi.decode(resultData, (uint256));
-            }
-
-            // Make sure the quoted buyAmount is available in the pool reserve
-            if (buyAmount >= poolReserveMakerAmount) {
-                // Assign pool reserve amount for all higher samples to break early
-                for (uint256 j = i; j < numSamples; j++) {
-                    makerTokenAmounts[j] = poolReserveMakerAmount;
-                }
-                break;
-            } else {
-                makerTokenAmounts[i] = buyAmount;
-            }
-
-            // Break early if there are 0 amounts
-            if (makerTokenAmounts[i] == 0) {
-                break;
-            }
-        }
-    }
-
-    /// @dev Sample buy quotes from Smoothy.
-    /// @param smoothyInfo Smoothy information specific to this token pair.
-    /// @param fromTokenIdx Index of the taker token (what to sell).
-    /// @param toTokenIdx Index of the maker token (what to buy).
-    /// @param makerTokenAmounts Maker token buy amount for each sample.
-    /// @return takerTokenAmounts Taker amounts sold at each maker token
-    ///         amount.
-    function sampleBuysFromSmoothy(
-        SmoothyInfo memory smoothyInfo,
-        int128 fromTokenIdx,
-        int128 toTokenIdx,
-        uint256[] memory makerTokenAmounts
-    )
-        public
-        view
-        returns (uint256[] memory takerTokenAmounts)
-    {
-        // Buys not supported so approximate it.
-        return _sampleApproximateBuys(
-            ApproximateBuyQuoteOpts({
-                makerTokenData: abi.encode(toTokenIdx, smoothyInfo),
-                takerTokenData: abi.encode(fromTokenIdx, smoothyInfo),
-                getSellQuoteCallback: _sampleSellForApproximateBuyFromSmoothy
-            }),
-            makerTokenAmounts
-        );
-    }
-
-    function _sampleSellForApproximateBuyFromSmoothy(
-        bytes memory takerTokenData,
-        bytes memory makerTokenData,
-        uint256 sellAmount
-    )
-        private
-        view
-        returns (uint256 buyAmount)
-    {
-        (int128 takerTokenIdx, SmoothyInfo memory smoothyInfo) =
-            abi.decode(takerTokenData, (int128, SmoothyInfo));
-        (int128 makerTokenIdx) =
-            abi.decode(makerTokenData, (int128));
-        (bool success, bytes memory resultData) =
-            address(this).staticcall(abi.encodeWithSelector(
-                this.sampleSellsFromSmoothy.selector,
-                smoothyInfo,
-                takerTokenIdx,
-                makerTokenIdx,
-                _toSingleValueArray(sellAmount)
-            ));
-        if (!success) {
-            return 0;
-        }
-        // solhint-disable-next-line indent
-        return abi.decode(resultData, (uint256[]))[0];
-    }
-}

packages/asset-swapper/contracts/src/SwapRevertSampler.sol

@@ -0,0 +1,412 @@
+
+
+// SPDX-License-Identifier: Apache-2.0
+/*
+
+  Copyright 2021 ZeroEx Intl.
+
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+
+*/
+
+pragma solidity ^0.6;
+pragma experimental ABIEncoderV2;
+
+import "./GasOverhead.sol";
+import "@0x/contracts-erc20/contracts/src/v06/IEtherTokenV06.sol";
+import "@0x/contracts-utils/contracts/src/v06/errors/LibRichErrorsV06.sol";
+
+interface IHackedERC20 {
+    function _setBalance(address owner, uint256 amount) external;
+    function _setEnabled(bool enabled) external;
+}
+
+contract SwapRevertSampler {
+    using LibRichErrorsV06 for bytes;
+
+    /// @dev Fixed address to register and read Gas overhead introduced by Swap revert sampling
+    GasOverhead private constant GAS_OVERHEAD = GasOverhead(0xDeF1000000000000000000000000000000001337);
+    /// @dev Maximum approximate (positive) error rate when approximating a buy quote.
+    uint256 private constant APPROXIMATE_BUY_TARGET_EPSILON_BPS = 0.0005e4;
+    /// @dev Maximum iterations to perform when approximating a buy quote.
+    uint256 private constant APPROXIMATE_BUY_MAX_ITERATIONS = 3;
+    uint256 private constant ONE_HUNDED_PERCENT_BPS = 1e4;
+    /// @dev Upper limit of gas to give to a single Swap call
+    uint256 private constant CALL_STIPEND = 2e6;
+
+
+    // solhint-disable no-empty-blocks
+    /// @dev Payable fallback to receive ETH from Kyber/WETH.
+    receive ()
+        external
+        payable
+    { }
+
+    struct SwapRevertSamplerQuoteOpts {
+        // Address of the token which is being sold
+        address sellToken;
+        // Address of the token which is wanted
+        address buyToken;
+        // Data required for the bridge to execute the swap
+        bytes bridgeData;
+        // Callback to retrieve a swap quote.
+        function (address sellToken, address buyToken, bytes memory bridgeData, uint256 sellAmount)
+            external
+            returns (uint256)
+            getSwapQuoteCallback;
+    }
+
+    struct SwapRevertSamplerBuyQuoteOpts {
+        // Address of the token which is being sold
+        address sellToken;
+        // Address of the token which is wanted
+        address buyToken;
+        // Data required for the bridge to execute the SELL_TOKEN->BUY_TOKEN swap
+        bytes sellTokenData;
+        // Data required for the bridge to execute the BUY_TOKEN->SELL_TOKEN swap
+        bytes buyTokenData;
+        // Callback to retrieve a swap quote.
+        function (address sellToken, address buyToken, bytes memory bridgeData, uint256 sellAmount)
+            external
+            returns (uint256)
+            getSwapQuoteCallback;
+    }
+
+    function _callRevert(
+        bytes4 selector,
+        address sellToken,
+        address buyToken,
+        bytes memory bridgeData,
+        uint256 amountIn
+    )
+        external
+    {
+        // Clear any registered overhead
+        try
+            GAS_OVERHEAD.clearOverhead()
+        { } catch { }
+        // Measure the gas
+        uint256 gasUsed = gasleft();
+        // Perform the sell
+        (bool success, bytes memory data) = address(this).call(
+            abi.encodeWithSelector(selector, sellToken, buyToken, bridgeData, amountIn)
+        );
+        gasUsed = gasUsed - gasleft();
+        // Remove any registered gas overhead
+        try
+            GAS_OVERHEAD.overhead()
+            returns (uint256 gasOverhead)
+        {
+            gasUsed = gasUsed - gasOverhead;
+        } catch { }
+
+        if (!success) {
+            data.rrevert();
+        }
+        // Revert with the amount bought
+        _revertSingleSwapSample(abi.decode(data, (uint256)), gasUsed);
+    }
+
+    /// @dev  Mints the sell token, then performs the swap, then reverts with the amount out.
+    /// The SwapRevertSamplerQuoteOpts has been unrolled here as our ABI encoder cannot support
+    /// encoding the function
+    function _mintCallRevert(
+        bytes4 selector,
+        address sellToken,
+        address buyToken,
+        bytes memory bridgeData,
+        uint256[] memory amountsIn
+    )
+        external
+    {
+        // We assume the amounts are ascending and that
+        // the underlying call can handle selling a specific amount
+        uint256 amountIn = amountsIn[amountsIn.length - 1];
+
+        if (sellToken == address(_getNativeWrappedToken())) {
+            try
+                IEtherTokenV06(payable(sellToken)).deposit{ value: amountIn }()
+            { } catch { }
+        } else {
+            IHackedERC20 hackedSellToken = IHackedERC20(payable(sellToken));
+            // Enable sell token to be tracked and shadowed
+            try
+                hackedSellToken._setEnabled(true)
+            { } catch { }
+
+            // Mint enough to sell
+            try
+                hackedSellToken._setBalance(address(this), amountIn)
+            { } catch { }
+        }
+
+        // Burn any excess ETH to avoid balance issues for sources which use ETH directly
+        address(0).transfer(address(this).balance);
+
+        uint256[] memory amountsOut = new uint256[](amountsIn.length);
+        uint256[] memory gasUsed = new uint256[](amountsIn.length);
+
+        for (uint256 i = 0; i < amountsIn.length; i++) {
+            try
+                this._callRevert{gas: CALL_STIPEND}(
+                    selector,
+                    sellToken,
+                    buyToken,
+                    bridgeData,
+                    amountsIn[i]
+                )
+            {
+                require(false, "Swap Sample should have reverted");
+            } catch (bytes memory reason) {
+                // Parse the reverted sample data
+                (amountsOut[i], gasUsed[i]) = _parseRevertedSingleSwapSample(reason);
+                // If we detect the amount out is 0 then we return early
+                // rather than continue performing excess work
+
+                // Some sources (Balancer) display issues, especially with small amounts
+                // Where the amountsOut can range, e.g 448,0,0,0,2476,3048,0,4279,4941,0,0,7133,
+
+                if (amountsOut[i] == 0) {
+                    break;
+                }
+            }
+        }
+        // Revert the entire sampling
+        _revertSwapSample(amountsOut, gasUsed);
+    }
+
+    function _sampleSwapQuotesRevert(
+        SwapRevertSamplerQuoteOpts memory opts,
+        uint256[] memory amountsIn
+    )
+        internal
+        returns (uint256[] memory gasUsed, uint256[] memory amountsOut)
+    {
+        try
+            this._mintCallRevert(
+                opts.getSwapQuoteCallback.selector,
+                opts.sellToken,
+                opts.buyToken,
+                opts.bridgeData,
+                amountsIn
+            )
+        {
+            require(false, "Swap Sample should have reverted");
+        } catch (bytes memory reason) {
+            // Parse the reverted sample datas
+            (amountsOut, gasUsed) = abi.decode(reason, (uint256[], uint256[]));
+        }
+    }
+
+    function _getNativeWrappedToken()
+        internal
+        view
+        returns (IEtherTokenV06)
+    {
+        uint256 chainId;
+        assembly {
+            chainId := chainid()
+        }
+        address token;
+        if (chainId == 1) {
+            // Ethereum Mainnet
+            token = 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2;
+        } else if (chainId == 3) {
+            // Ropsten
+            token = 0xc778417E063141139Fce010982780140Aa0cD5Ab;
+        } else if (chainId == 4) {
+            // Rinkeby
+            token = 0xc778417E063141139Fce010982780140Aa0cD5Ab;
+        } else if (chainId == 42) {
+            // Kovan
+            token = 0xd0A1E359811322d97991E03f863a0C30C2cF029C;
+        } else if (chainId == 56) {
+            // BSC 
+            token = 0xbb4CdB9CBd36B01bD1cBaEBF2De08d9173bc095c;
+        } else if (chainId == 137) {
+            // Polygon
+            token = 0x0d500B1d8E8eF31E21C99d1Db9A6444d3ADf1270;
+        } else if (chainId == 1337) {
+            // 0x Ganache
+            token = 0x0B1ba0af832d7C05fD64161E0Db78E85978E8082;
+        }
+        if (token == address(0)) {
+            revert("No native wrapped token");
+        }
+        return IEtherTokenV06(token);
+    }
+
+    function _revertSingleSwapSample(
+        uint256 amount,
+        uint256 gasUsed
+    )
+        internal
+    {
+        // Revert it so there is no state change
+        assembly {
+            mstore(0, amount)
+            mstore(32, gasUsed)
+            revert(0, 64)
+        }
+    }
+
+    function _revertSwapSample(
+        uint256[] memory amounts,
+        uint256[] memory gasUsed
+    )
+        internal
+    {
+        bytes memory data = abi.encode(amounts, gasUsed);
+        // Revert it so there is no state change
+        assembly {
+            revert(add(data, 32), mload(data))
+        }
+    }
+
+    /// @dev Parses the reverted swap sample data. If no amount
+    ///      is decoded, 0 is returned.
+    /// @param reason the string which contains the possible
+    ///               sample amount
+    /// @return the decoded sample amount or 0
+    /// @return the gas used in the sample
+    function _parseRevertedSingleSwapSample(
+        bytes memory reason
+    )
+        internal
+        pure
+        returns (uint256, uint256)
+    {
+        if (reason.length != 64) {
+            return (0,0);
+        }
+        return abi.decode(reason, (uint256, uint256));
+    }
+
+    function _sampleSwapApproximateBuys(
+        SwapRevertSamplerBuyQuoteOpts memory opts,
+        uint256[] memory makerTokenAmounts
+    )
+        internal
+        returns (uint256[] memory gasUsed, uint256[] memory takerTokenAmounts)
+    {
+        if (makerTokenAmounts.length == 0) {
+            return (gasUsed, takerTokenAmounts);
+        }
+
+        takerTokenAmounts = new uint256[](makerTokenAmounts.length);
+        gasUsed = new uint256[](makerTokenAmounts.length);
+
+        uint256[] memory sellAmounts = new uint256[](1);
+        sellAmounts[0] = makerTokenAmounts[0];
+
+        SwapRevertSamplerQuoteOpts memory sellOpts = SwapRevertSamplerQuoteOpts({
+            sellToken: opts.sellToken,
+            buyToken: opts.buyToken,
+            bridgeData: opts.sellTokenData,
+            getSwapQuoteCallback: opts.getSwapQuoteCallback
+        });
+
+        SwapRevertSamplerQuoteOpts memory buyOpts = SwapRevertSamplerQuoteOpts({
+            sellToken: opts.buyToken,
+            buyToken: opts.sellToken,
+            bridgeData: opts.buyTokenData,
+            getSwapQuoteCallback: opts.getSwapQuoteCallback
+        });
+        // Inverted, perform a sell of the token the user wants to buy
+        (, sellAmounts) = _sampleSwapQuotesRevert(buyOpts, sellAmounts);
+        if (sellAmounts.length == 0 || sellAmounts[0] == 0) {
+            return (gasUsed, takerTokenAmounts);
+        }
+
+        uint256[] memory buyAmounts;
+        // Sell of the token the user wishes to dispose, see how much we buy
+        (, buyAmounts) = _sampleSwapQuotesRevert(sellOpts, sellAmounts);
+
+        if (buyAmounts.length == 0 || buyAmounts[0] == 0) {
+            return (gasUsed, takerTokenAmounts);
+        }
+
+        for (uint256 i = 0; i < makerTokenAmounts.length; i++) {
+            uint256[] memory _gasUsed;
+            for (uint256 iter = 0; iter < APPROXIMATE_BUY_MAX_ITERATIONS; iter++) {
+                // adjustedSellAmount = previousSellAmount * (target/actual) * JUMP_MULTIPLIER
+                sellAmounts[0] = _safeGetPartialAmountCeil(
+                    makerTokenAmounts[i],
+                    buyAmounts[0],
+                    sellAmounts[0]
+                );
+                if (sellAmounts.length == 0 || sellAmounts[0] == 0) {
+                    break;
+                }
+                sellAmounts[0] = _safeGetPartialAmountCeil(
+                    (ONE_HUNDED_PERCENT_BPS + APPROXIMATE_BUY_TARGET_EPSILON_BPS),
+                    ONE_HUNDED_PERCENT_BPS,
+                    sellAmounts[0]
+                );
+                if (sellAmounts.length == 0 || sellAmounts[0] == 0) {
+                    break;
+                }
+                uint256[] memory _buyAmounts;
+                (_gasUsed, _buyAmounts) = _sampleSwapQuotesRevert(sellOpts, sellAmounts);
+                if (_buyAmounts.length == 0 || _buyAmounts[0] == 0) {
+                    break;
+                }
+                // We re-use buyAmount next iteration, only assign if it is
+                // non zero
+                buyAmounts = _buyAmounts;
+                // If we've reached our goal, exit early
+                if (buyAmounts[0] >= makerTokenAmounts[i]) {
+                    uint256 eps =
+                        (buyAmounts[0] - makerTokenAmounts[i]) * ONE_HUNDED_PERCENT_BPS /
+                        makerTokenAmounts[i];
+                    if (eps <= APPROXIMATE_BUY_TARGET_EPSILON_BPS) {
+                        break;
+                    }
+                }
+            }
+            // We've encountered reverts, so bail
+            if (_gasUsed.length == 0 || _gasUsed[0] == 0) {
+                return (gasUsed, takerTokenAmounts);
+            }
+
+            if (buyAmounts.length > 0) {
+                gasUsed[i] = _gasUsed[0];
+                // We do our best to close in on the requested amount, but we can either over buy or under buy and exit
+                // if we hit a max iteration limit
+                // We scale the sell amount to get the approximate target
+                takerTokenAmounts[i] = _safeGetPartialAmountCeil(
+                    makerTokenAmounts[i],
+                    buyAmounts[0],
+                    sellAmounts[0]
+                );
+            }
+        }
+    }
+
+    function _safeGetPartialAmountCeil(
+        uint256 numerator,
+        uint256 denominator,
+        uint256 target
+    )
+        internal
+        view
+        returns (uint256 partialAmount)
+    {
+        if (numerator == 0 || target == 0 || denominator == 0) return 0;
+        uint256 c = numerator * target;
+        if (c / numerator != target) return 0;
+        return (c + (denominator - 1)) / denominator;
+    }
+
+
+}

packages/asset-swapper/contracts/src/TwoHopSampler.sol

@@ -40,10 +40,11 @@ contract TwoHopSampler {
         returns (
             HopInfo memory firstHop,
             HopInfo memory secondHop,
+            uint256 intermediateAssetAmount,
             uint256 buyAmount
         )
     {
-        uint256 intermediateAssetAmount = 0;
+        intermediateAssetAmount = 0;
         for (uint256 i = 0; i != firstHopCalls.length; ++i) {
             firstHopCalls[i].writeUint256(firstHopCalls[i].length - 32, sellAmount);
             (bool didSucceed, bytes memory returnData) = address(this).call(firstHopCalls[i]);
@@ -57,7 +58,7 @@ contract TwoHopSampler {
             }
         }
         if (intermediateAssetAmount == 0) {
-            return (firstHop, secondHop, buyAmount);
+            return (firstHop, secondHop, intermediateAssetAmount, buyAmount);
         }
         for (uint256 j = 0; j != secondHopCalls.length; ++j) {
             secondHopCalls[j].writeUint256(secondHopCalls[j].length - 32, intermediateAssetAmount);

packages/asset-swapper/contracts/src/UniswapSampler.sol

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: Apache-2.0
 /*
 
-  Copyright 2020 ZeroEx Intl.
+  Copyright 2021 ZeroEx Intl.
 
   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
@@ -20,32 +20,43 @@
 pragma solidity ^0.6;
 pragma experimental ABIEncoderV2;
 
-import "./interfaces/IUniswapExchangeQuotes.sol";
-import "./SamplerUtils.sol";
-
-
-interface IUniswapExchangeFactory {
-
-    /// @dev Get the exchange for a token.
-    /// @param tokenAddress The address of the token contract.
-    function getExchange(address tokenAddress)
-        external
-        view
-        returns (address);
-}
-
+import "@0x/contracts-zero-ex/contracts/src/transformers/bridges/mixins/MixinUniswap.sol";
+import "./SwapRevertSampler.sol";
 
 contract UniswapSampler is
-    SamplerUtils
+    MixinUniswap,
+    SwapRevertSampler
 {
-    /// @dev Gas limit for Uniswap calls.
-    uint256 constant private UNISWAP_CALL_GAS = 150e3; // 150k
+
+    constructor(IEtherTokenV06 weth)
+        public
+        MixinUniswap(weth)
+    { }
+
+    function sampleSwapFromUniswap(
+        address sellToken,
+        address buyToken,
+        bytes memory bridgeData,
+        uint256 takerTokenAmount
+    )
+        external
+        returns (uint256)
+    {
+        return _tradeUniswapInternal(
+            _getNativeWrappedToken(),
+            IERC20TokenV06(sellToken),
+            IERC20TokenV06(buyToken),
+            takerTokenAmount,
+            bridgeData
+        );
+    }
 
     /// @dev Sample sell quotes from Uniswap.
     /// @param router Address of the Uniswap Router
     /// @param takerToken Address of the taker token (what to sell).
     /// @param makerToken Address of the maker token (what to buy).
     /// @param takerTokenAmounts Taker token sell amount for each sample.
+    /// @return gasUsed gas consumed in each sample sell
     /// @return makerTokenAmounts Maker amounts bought at each taker token
     ///         amount.
     function sampleSellsFromUniswap(
@@ -55,59 +66,24 @@ contract UniswapSampler is
         uint256[] memory takerTokenAmounts
     )
         public
-        view
-        returns (uint256[] memory makerTokenAmounts)
+        returns (uint256[] memory gasUsed, uint256[] memory makerTokenAmounts)
     {
-        _assertValidPair(makerToken, takerToken);
-        uint256 numSamples = takerTokenAmounts.length;
-        makerTokenAmounts = new uint256[](numSamples);
-
-        IUniswapExchangeQuotes takerTokenExchange = takerToken == address(0) ?
-            IUniswapExchangeQuotes(0) : _getUniswapExchange(router, takerToken);
-        IUniswapExchangeQuotes makerTokenExchange = makerToken == address(0) ?
-            IUniswapExchangeQuotes(0) : _getUniswapExchange(router, makerToken);
-        for (uint256 i = 0; i < numSamples; i++) {
-            bool didSucceed = true;
-            if (makerToken == address(0)) {
-                (makerTokenAmounts[i], didSucceed) = _callUniswapExchangePriceFunction(
-                    address(takerTokenExchange),
-                    takerTokenExchange.getTokenToEthInputPrice.selector,
-                    takerTokenAmounts[i]
-                );
-            } else if (takerToken == address(0)) {
-                (makerTokenAmounts[i], didSucceed) = _callUniswapExchangePriceFunction(
-                    address(makerTokenExchange),
-                    makerTokenExchange.getEthToTokenInputPrice.selector,
-                    takerTokenAmounts[i]
-                );
-            } else {
-                uint256 ethBought;
-                (ethBought, didSucceed) = _callUniswapExchangePriceFunction(
-                    address(takerTokenExchange),
-                    takerTokenExchange.getTokenToEthInputPrice.selector,
-                    takerTokenAmounts[i]
-                );
-                if (ethBought != 0) {
-                    (makerTokenAmounts[i], didSucceed) = _callUniswapExchangePriceFunction(
-                        address(makerTokenExchange),
-                        makerTokenExchange.getEthToTokenInputPrice.selector,
-                        ethBought
-                    );
-                } else {
-                    makerTokenAmounts[i] = 0;
-                }
-            }
-            // Break early if amounts are 0
-            if (!didSucceed || makerTokenAmounts[i] == 0) {
-                break;
-            }
-        }
+        (gasUsed, makerTokenAmounts) = _sampleSwapQuotesRevert(
+            SwapRevertSamplerQuoteOpts({
+                sellToken: takerToken,
+                buyToken: makerToken,
+                bridgeData: abi.encode(router),
+                getSwapQuoteCallback: this.sampleSwapFromUniswap
+            }),
+            takerTokenAmounts
+        );
     }
 
     /// @dev Sample buy quotes from Uniswap.
     /// @param takerToken Address of the taker token (what to sell).
     /// @param makerToken Address of the maker token (what to buy).
     /// @param makerTokenAmounts Maker token sell amount for each sample.
+    /// @return gasUsed gas consumed in each sample sell
     /// @return takerTokenAmounts Taker amounts sold at each maker token
     ///         amount.
     function sampleBuysFromUniswap(
@@ -117,98 +93,18 @@ contract UniswapSampler is
         uint256[] memory makerTokenAmounts
     )
         public
-        view
-        returns (uint256[] memory takerTokenAmounts)
+        returns (uint256[] memory gasUsed, uint256[] memory takerTokenAmounts)
     {
-        _assertValidPair(makerToken, takerToken);
-        uint256 numSamples = makerTokenAmounts.length;
-        takerTokenAmounts = new uint256[](numSamples);
-
-        IUniswapExchangeQuotes takerTokenExchange = takerToken == address(0) ?
-            IUniswapExchangeQuotes(0) : _getUniswapExchange(router, takerToken);
-        IUniswapExchangeQuotes makerTokenExchange = makerToken == address(0) ?
-            IUniswapExchangeQuotes(0) : _getUniswapExchange(router, makerToken);
-        for (uint256 i = 0; i < numSamples; i++) {
-            bool didSucceed = true;
-            if (makerToken == address(0)) {
-                (takerTokenAmounts[i], didSucceed) = _callUniswapExchangePriceFunction(
-                    address(takerTokenExchange),
-                    takerTokenExchange.getTokenToEthOutputPrice.selector,
-                    makerTokenAmounts[i]
-                );
-            } else if (takerToken == address(0)) {
-                (takerTokenAmounts[i], didSucceed) = _callUniswapExchangePriceFunction(
-                    address(makerTokenExchange),
-                    makerTokenExchange.getEthToTokenOutputPrice.selector,
-                    makerTokenAmounts[i]
-                );
-            } else {
-                uint256 ethSold;
-                (ethSold, didSucceed) = _callUniswapExchangePriceFunction(
-                    address(makerTokenExchange),
-                    makerTokenExchange.getEthToTokenOutputPrice.selector,
-                    makerTokenAmounts[i]
-                );
-                if (ethSold != 0) {
-                    (takerTokenAmounts[i], didSucceed) = _callUniswapExchangePriceFunction(
-                        address(takerTokenExchange),
-                        takerTokenExchange.getTokenToEthOutputPrice.selector,
-                        ethSold
-                    );
-                } else {
-                    takerTokenAmounts[i] = 0;
-                }
-            }
-            // Break early if amounts are 0
-            if (!didSucceed || takerTokenAmounts[i] == 0) {
-                break;
-            }
-        }
-    }
-
-    /// @dev Gracefully calls a Uniswap pricing function.
-    /// @param uniswapExchangeAddress Address of an `IUniswapExchangeQuotes` exchange.
-    /// @param functionSelector Selector of the target function.
-    /// @param inputAmount Quantity parameter particular to the pricing function.
-    /// @return outputAmount The returned amount from the function call. Will be
-    ///         zero if the call fails or if `uniswapExchangeAddress` is zero.
-    function _callUniswapExchangePriceFunction(
-        address uniswapExchangeAddress,
-        bytes4 functionSelector,
-        uint256 inputAmount
-    )
-        private
-        view
-        returns (uint256 outputAmount, bool didSucceed)
-    {
-        if (uniswapExchangeAddress == address(0)) {
-            return (outputAmount, didSucceed);
-        }
-        bytes memory resultData;
-        (didSucceed, resultData) =
-            uniswapExchangeAddress.staticcall.gas(UNISWAP_CALL_GAS)(
-                abi.encodeWithSelector(
-                    functionSelector,
-                    inputAmount
-                ));
-        if (didSucceed) {
-            outputAmount = abi.decode(resultData, (uint256));
-        }
-    }
-
-    /// @dev Retrive an existing Uniswap exchange contract.
-    ///      Throws if the exchange does not exist.
-    /// @param router Address of the Uniswap router.
-    /// @param tokenAddress Address of the token contract.
-    /// @return exchange `IUniswapExchangeQuotes` for the token.
-    function _getUniswapExchange(address router, address tokenAddress)
-        private
-        view
-        returns (IUniswapExchangeQuotes exchange)
-    {
-        exchange = IUniswapExchangeQuotes(
-            address(IUniswapExchangeFactory(router)
-            .getExchange(tokenAddress))
+        (gasUsed, takerTokenAmounts) = _sampleSwapApproximateBuys(
+            SwapRevertSamplerBuyQuoteOpts({
+                sellToken: takerToken,
+                buyToken: makerToken,
+                sellTokenData: abi.encode(router),
+                buyTokenData: abi.encode(router),
+                getSwapQuoteCallback: this.sampleSwapFromUniswap
+            }),
+            makerTokenAmounts
         );
     }
+
 }

packages/asset-swapper/contracts/src/UniswapV2Sampler.sol

@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: Apache-2.0
 /*
 
-  Copyright 2020 ZeroEx Intl.
+  Copyright 2021 ZeroEx Intl.
 
   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
@@ -21,17 +21,36 @@ pragma solidity ^0.6;
 pragma experimental ABIEncoderV2;
 
 import "./interfaces/IUniswapV2Router01.sol";
+import "@0x/contracts-zero-ex/contracts/src/transformers/bridges/mixins/MixinUniswapV2.sol";
+import "./SwapRevertSampler.sol";
 
 
-contract UniswapV2Sampler
+contract UniswapV2Sampler is
+    MixinUniswapV2,
+    SwapRevertSampler
 {
-    /// @dev Gas limit for UniswapV2 calls.
-    uint256 constant private UNISWAPV2_CALL_GAS = 150e3; // 150k
+
+    function sampleSwapFromUniswapV2(
+        address sellToken,
+        address buyToken,
+        bytes memory bridgeData,
+        uint256 takerTokenAmount
+    )
+        external
+        returns (uint256)
+    {
+        return _tradeUniswapV2(
+            IERC20TokenV06(buyToken),
+            takerTokenAmount,
+            bridgeData
+        );
+    }
 
     /// @dev Sample sell quotes from UniswapV2.
     /// @param router Router to look up tokens and amounts
     /// @param path Token route. Should be takerToken -> makerToken
     /// @param takerTokenAmounts Taker token sell amount for each sample.
+    /// @return gasUsed gas consumed for each sample amount
     /// @return makerTokenAmounts Maker amounts bought at each taker token
     ///         amount.
     function sampleSellsFromUniswapV2(
@@ -40,34 +59,24 @@ contract UniswapV2Sampler
         uint256[] memory takerTokenAmounts
     )
         public
-        view
-        returns (uint256[] memory makerTokenAmounts)
+        returns (uint256[] memory gasUsed, uint256[] memory makerTokenAmounts)
     {
-        uint256 numSamples = takerTokenAmounts.length;
-        makerTokenAmounts = new uint256[](numSamples);
-        for (uint256 i = 0; i < numSamples; i++) {
-            try
-                IUniswapV2Router01(router).getAmountsOut
-                    {gas: UNISWAPV2_CALL_GAS}
-                    (takerTokenAmounts[i], path)
-                returns (uint256[] memory amounts)
-            {
-                makerTokenAmounts[i] = amounts[path.length - 1];
-                // Break early if there are 0 amounts
-                if (makerTokenAmounts[i] == 0) {
-                    break;
-                }
-            } catch (bytes memory) {
-                // Swallow failures, leaving all results as zero.
-                break;
-            }
-        }
+        (gasUsed, makerTokenAmounts) = _sampleSwapQuotesRevert(
+            SwapRevertSamplerQuoteOpts({
+                sellToken: path[0],
+                buyToken: path[path.length - 1],
+                bridgeData: abi.encode(router, path),
+                getSwapQuoteCallback: this.sampleSwapFromUniswapV2
+            }),
+            takerTokenAmounts
+        );
     }
 
     /// @dev Sample buy quotes from UniswapV2.
     /// @param router Router to look up tokens and amounts
     /// @param path Token route. Should be takerToken -> makerToken.
     /// @param makerTokenAmounts Maker token buy amount for each sample.
+    /// @return gasUsed gas consumed for each sample amount
     /// @return takerTokenAmounts Taker amounts sold at each maker token
     ///         amount.
     function sampleBuysFromUniswapV2(
@@ -76,27 +85,22 @@ contract UniswapV2Sampler
         uint256[] memory makerTokenAmounts
     )
         public
-        view
-        returns (uint256[] memory takerTokenAmounts)
+        returns (uint256[] memory gasUsed, uint256[] memory takerTokenAmounts)
     {
-        uint256 numSamples = makerTokenAmounts.length;
-        takerTokenAmounts = new uint256[](numSamples);
-        for (uint256 i = 0; i < numSamples; i++) {
-            try
-                IUniswapV2Router01(router).getAmountsIn
-                    {gas: UNISWAPV2_CALL_GAS}
-                    (makerTokenAmounts[i], path)
-                returns (uint256[] memory amounts)
-            {
-                takerTokenAmounts[i] = amounts[0];
-                // Break early if there are 0 amounts
-                if (takerTokenAmounts[i] == 0) {
-                    break;
-                }
-            } catch (bytes memory) {
-                // Swallow failures, leaving all results as zero.
-                break;
-            }
+        address[] memory reversedPath = new address[](path.length);
+        for (uint256 i = 0; i < path.length; ++i) {
+            reversedPath[i] = path[path.length - i - 1];
         }
+
+        (gasUsed, takerTokenAmounts) = _sampleSwapApproximateBuys(
+            SwapRevertSamplerBuyQuoteOpts({
+                sellToken: path[0],
+                buyToken: path[path.length - 1],
+                sellTokenData: abi.encode(router, path),
+                buyTokenData: abi.encode(router, reversedPath),
+                getSwapQuoteCallback: this.sampleSwapFromUniswapV2
+            }),
+            makerTokenAmounts
+        );
     }
 }

packages/asset-swapper/contracts/src/UniswapV3Sampler.sol

@@ -21,18 +21,16 @@ pragma solidity ^0.6;
 pragma experimental ABIEncoderV2;
 
 import "@0x/contracts-erc20/contracts/src/v06/IERC20TokenV06.sol";
+import "@0x/contracts-utils/contracts/src/v06/errors/LibRichErrorsV06.sol";
+
+import "@0x/contracts-zero-ex/contracts/src/transformers/bridges/mixins/MixinUniswapV3.sol";
+import "./SwapRevertSampler.sol";
 
 interface IUniswapV3Quoter {
     function factory()
         external
         view
         returns (IUniswapV3Factory factory);
-    function quoteExactInput(bytes memory path, uint256 amountIn)
-        external
-        returns (uint256 amountOut);
-    function quoteExactOutput(bytes memory path, uint256 amountOut)
-        external
-        returns (uint256 amountIn);
 }
 
 interface IUniswapV3Factory {
@@ -48,26 +46,47 @@ interface IUniswapV3Pool {
     function fee() external view returns (uint24);
 }
 
-contract UniswapV3Sampler
+contract UniswapV3Sampler is
+    MixinUniswapV3,
+    SwapRevertSampler
 {
-    /// @dev Gas limit for UniswapV3 calls. This is 100% a guess.
-    uint256 constant private QUOTE_GAS = 300e3;
+    using LibRichErrorsV06 for bytes;
+
+    function sampleSwapFromUniswapV3(
+        address sellToken,
+        address buyToken,
+        bytes memory bridgeData,
+        uint256 takerTokenAmount
+    )
+        external
+        returns (uint256)
+    {
+        return _tradeUniswapV3(
+            IERC20TokenV06(sellToken),
+            takerTokenAmount,
+            bridgeData
+        );
+    }
 
     /// @dev Sample sell quotes from UniswapV3.
     /// @param quoter UniswapV3 Quoter contract.
+    /// @param router UniswapV3 Router contract.
     /// @param path Token route. Should be takerToken -> makerToken
     /// @param takerTokenAmounts Taker token sell amount for each sample.
     /// @return uniswapPaths The encoded uniswap path for each sample.
+    /// @return gasUsed gas consumed in each sample sell
     /// @return makerTokenAmounts Maker amounts bought at each taker token
     ///         amount.
     function sampleSellsFromUniswapV3(
         IUniswapV3Quoter quoter,
+        address router,
         IERC20TokenV06[] memory path,
         uint256[] memory takerTokenAmounts
     )
         public
         returns (
             bytes[] memory uniswapPaths,
+            uint256[] memory gasUsed,
             uint256[] memory makerTokenAmounts
         )
     {
@@ -75,50 +94,57 @@ contract UniswapV3Sampler
             _getValidPoolPaths(quoter.factory(), path, 0);
 
         makerTokenAmounts = new uint256[](takerTokenAmounts.length);
+        gasUsed = new uint256[](takerTokenAmounts.length);
         uniswapPaths = new bytes[](takerTokenAmounts.length);
 
-        for (uint256 i = 0; i < takerTokenAmounts.length; ++i) {
-            // Pick the best result from all the paths.
-            bytes memory topUniswapPath;
-            uint256 topBuyAmount = 0;
-            for (uint256 j = 0; j < poolPaths.length; ++j) {
-                bytes memory uniswapPath = _toUniswapPath(path, poolPaths[j]);
-                try
-                    quoter.quoteExactInput
-                        { gas: QUOTE_GAS }
-                        (uniswapPath, takerTokenAmounts[i])
-                        returns (uint256 buyAmount)
-                {
-                    if (topBuyAmount <= buyAmount) {
-                        topBuyAmount = buyAmount;
-                        topUniswapPath = uniswapPath;
-                    }
-                } catch { }
+        for (uint256 i = 0; i < poolPaths.length; ++i) {
+            bytes memory _uniswapPath = _toUniswapPath(path, poolPaths[i]);
+            (
+                uint256[] memory _gasUsed,
+                uint256[] memory _makerTokenAmounts
+            ) = _sampleSwapQuotesRevert(
+                SwapRevertSamplerQuoteOpts({
+                    sellToken: address(path[0]),
+                    buyToken: address(path[path.length - 1]),
+                    bridgeData: abi.encode(router, _uniswapPath),
+                    getSwapQuoteCallback: this.sampleSwapFromUniswapV3
+                }),
+                takerTokenAmounts
+            );
+            for (uint256 j = 0; j < _makerTokenAmounts.length; ++j) {
+                // Break early if we can't complete the sells.
+                if (_makerTokenAmounts[j] == 0) {
+                    break;
+                }
+                // If this is better than what we have found, prefer it
+                if (makerTokenAmounts[j] <= _makerTokenAmounts[j]) {
+                    makerTokenAmounts[j] = _makerTokenAmounts[j];
+                    gasUsed[j] = _gasUsed[j];
+                    uniswapPaths[j] = _uniswapPath;
+                }
             }
-            // Break early if we can't complete the buys.
-            if (topBuyAmount == 0) {
-                break;
-            }
-            makerTokenAmounts[i] = topBuyAmount;
-            uniswapPaths[i] = topUniswapPath;
         }
     }
 
     /// @dev Sample buy quotes from UniswapV3.
     /// @param quoter UniswapV3 Quoter contract.
+    /// @param router UniswapV3 Router contract.
     /// @param path Token route. Should be takerToken -> makerToken.
     /// @param makerTokenAmounts Maker token buy amount for each sample.
     /// @return uniswapPaths The encoded uniswap path for each sample.
+    /// @return gasUsed gas consumed in each sample sell
     /// @return takerTokenAmounts Taker amounts sold at each maker token
     ///         amount.
     function sampleBuysFromUniswapV3(
         IUniswapV3Quoter quoter,
+        address router,
         IERC20TokenV06[] memory path,
         uint256[] memory makerTokenAmounts
     )
         public
         returns (
             bytes[] memory uniswapPaths,
+            uint256[] memory gasUsed,
             uint256[] memory takerTokenAmounts
         )
     {
@@ -127,37 +153,43 @@ contract UniswapV3Sampler
         IERC20TokenV06[] memory reversedPath = _reverseTokenPath(path);
 
         takerTokenAmounts = new uint256[](makerTokenAmounts.length);
+        gasUsed = new uint256[](makerTokenAmounts.length);
         uniswapPaths = new bytes[](makerTokenAmounts.length);
 
-        for (uint256 i = 0; i < makerTokenAmounts.length; ++i) {
-            // Pick the best result from all the paths.
-            bytes memory topUniswapPath;
-            uint256 topSellAmount = 0;
-            for (uint256 j = 0; j < poolPaths.length; ++j) {
-                // quoter requires path to be reversed for buys.
-                bytes memory uniswapPath = _toUniswapPath(
-                    reversedPath,
-                    _reversePoolPath(poolPaths[j])
-                );
-                try
-                    quoter.quoteExactOutput
-                        { gas: QUOTE_GAS }
-                        (uniswapPath, makerTokenAmounts[i])
-                        returns (uint256 sellAmount)
-                {
-                    if (topSellAmount == 0 || topSellAmount >= sellAmount) {
-                        topSellAmount = sellAmount;
-                        // But the output path should still be encoded for sells.
-                        topUniswapPath = _toUniswapPath(path, poolPaths[j]);
-                    }
-                } catch {}
+        for (uint256 i = 0; i < poolPaths.length; ++i) {
+            (
+                uint256[] memory _gasUsed,
+                uint256[] memory _takerTokenAmounts
+            ) = _sampleSwapApproximateBuys(
+                SwapRevertSamplerBuyQuoteOpts({
+                    sellToken: address(path[0]),
+                    buyToken: address(path[path.length - 1]),
+                    sellTokenData: abi.encode(router, _toUniswapPath(path, poolPaths[i])),
+                    buyTokenData: abi.encode(
+                        router,
+                        _toUniswapPath(
+                            reversedPath,
+                            _reversePoolPath(poolPaths[i])
+                        )
+                    ),
+                    getSwapQuoteCallback: this.sampleSwapFromUniswapV3
+                }),
+                makerTokenAmounts
+            );
+
+            for (uint256 j = 0; j < _takerTokenAmounts.length; ++j) {
+                // Break early if we can't complete the buys.
+                if (_takerTokenAmounts[j] == 0) {
+                    break;
+                }
+                // We can go from high to low here
+                if (takerTokenAmounts[j] == 0 || takerTokenAmounts[j] >= _takerTokenAmounts[j]) {
+                    takerTokenAmounts[j] = _takerTokenAmounts[j];
+                    gasUsed[j] = _gasUsed[j];
+                    // But the output path should still be encoded for sells.
+                    uniswapPaths[j] = _toUniswapPath(path, poolPaths[i]);
+                }
             }
-            // Break early if we can't complete the buys.
-            if (topSellAmount == 0) {
-                break;
-            }
-            takerTokenAmounts[i] = topSellAmount;
-            uniswapPaths[i] = topUniswapPath;
         }
     }
 
@@ -268,7 +300,7 @@ contract UniswapV3Sampler
                 return false;
             }
         }
-        // Must have a balance of both tokens.
+        // // Must have a balance of both tokens.
         if (pool.token0().balanceOf(address(pool)) == 0) {
             return false;
         }

packages/asset-swapper/contracts/src/UtilitySampler.sol

@@ -77,4 +77,24 @@ contract UtilitySampler {
         assembly { size := extcodesize(account) }
         return size > 0;
     }
+
+    function getCode(address addr)
+        public
+        view
+        returns (bytes memory code)
+    {
+        assembly {
+            // retrieve the size of the code, this needs assembly
+            let size := extcodesize(addr)
+            // allocate output byte array - this could also be done without assembly
+            // by using o_code = new bytes(size)
+            code := mload(0x40)
+            // new "memory end" including padding
+            mstore(0x40, add(code, and(add(add(size, 0x20), 0x1f), not(0x1f))))
+            // store length in memory
+            mstore(code, size)
+            // actually retrieve the code, this needs assembly
+            extcodecopy(addr, add(code, 0x20), 0, size)
+        }
+    }
 }

packages/asset-swapper/contracts/src/interfaces/IBalancer.sol

@@ -1,44 +0,0 @@
-// SPDX-License-Identifier: Apache-2.0
-/*
-
-  Copyright 2020 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.6;
-
-
-interface IBalancer {
-    function isBound(address t) external view returns (bool);
-    function getDenormalizedWeight(address token) external view returns (uint256);
-    function getBalance(address token) external view returns (uint256);
-    function getSwapFee() external view returns (uint256);
-    function calcOutGivenIn(
-        uint256 tokenBalanceIn,
-        uint256 tokenWeightIn,
-        uint256 tokenBalanceOut,
-        uint256 tokenWeightOut,
-        uint256 tokenAmountIn,
-        uint256 swapFee
-    ) external pure returns (uint256 tokenAmountOut);
-    function calcInGivenOut(
-        uint256 tokenBalanceIn,
-        uint256 tokenWeightIn,
-        uint256 tokenBalanceOut,
-        uint256 tokenWeightOut,
-        uint256 tokenAmountOut,
-        uint256 swapFee
-    ) external pure returns (uint256 tokenAmountIn);
-}

packages/asset-swapper/contracts/src/interfaces/IBancor.sol

@@ -1,33 +0,0 @@
-// SPDX-License-Identifier: Apache-2.0
-/*
-
-  Copyright 2020 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.6;
-
-
-interface IBancor {}
-
-interface IBancorNetwork {
-  function conversionPath(address _sourceToken, address _targetToken) external view returns (address[] memory);
-  function rateByPath(address[] memory _path, uint256 _amount) external view returns (uint256);
-}
-
-interface IBancorRegistry {
-    function getAddress(bytes32 _contractName) external view returns (address);
-    function BANCOR_NETWORK() external view returns (bytes32);
-}

packages/asset-swapper/contracts/src/interfaces/ICurve.sol

@@ -1,72 +0,0 @@
-// SPDX-License-Identifier: Apache-2.0
-/*
-
-  Copyright 2020 ZeroEx Intl.
-
-  Licensed under the Apache License, Version 2.0 (the "License");
-  you may not use this file except in compliance with the License.
-  You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-  Unless required by applicable law or agreed to in writing, software
-  distributed under the License is distributed on an "AS IS" BASIS,
-  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-  See the License for the specific language governing permissions and
-  limitations under the License.
-
-*/
-
-pragma solidity ^0.6;
-
-
-// solhint-disable func-name-mixedcase
-interface ICurve {
-
-    /// @dev Sell `sellAmount` of `fromToken` token and receive `toToken` token.
-    ///      This function exists on later versions of Curve (USDC/DAI/USDT)
-    /// @param i The token index being sold.
-    /// @param j The token index being bought.
-    /// @param sellAmount The amount of token being bought.
-    /// @param minBuyAmount The minimum buy amount of the token being bought.
-    function exchange_underlying(
-        int128 i,
-        int128 j,
-        uint256 sellAmount,
-        uint256 minBuyAmount
-    )
-        external;
-
-    /// @dev Get the amount of `toToken` by selling `sellAmount` of `fromToken`
-    /// @param i The token index being sold.
-    /// @param j The token index being bought.
-    /// @param sellAmount The amount of token being bought.
-    function get_dy_underlying(
-        int128 i,
-        int128 j,
-        uint256 sellAmount
-    )
-        external
-        returns (uint256 dy);
-
-    /// @dev Get the amount of `fromToken` by buying `buyAmount` of `toToken`
-    ///      This function exists on later versions of Curve (USDC/DAI/USDT)
-    /// @param i The token index being sold.
-    /// @param j The token index being bought.
-    /// @param buyAmount The amount of token being bought.
-    function get_dx_underlying(
-        int128 i,
-        int128 j,
-        uint256 buyAmount
-    )
-        external
-        returns (uint256 dx);
-
-    /// @dev Get the underlying token address from the token index
-    /// @param i The token index.
-    function underlying_coins(
-        int128 i
-    )
-        external
-        returns (address tokenAddress);
-}