Cleaned up interface for decoding proxy data. Added a general decoder, which should be useful for the forwarding contract code.

packages/contracts/src/utils/asset_proxy_utils.ts

@@ -2,7 +2,7 @@ import { BigNumber } from '@0xproject/utils';
 import BN = require('bn.js');
 import ethUtil = require('ethereumjs-util');
 
-import { AssetProxyId } from './types';
+import { AssetProxyId, ERC20ProxyData, ERC721ProxyData, ProxyData } from './types';
 
 export const assetProxyUtils = {
     encodeAssetProxyId(assetProxyId: AssetProxyId): Buffer {
@@ -43,7 +43,7 @@ export const assetProxyUtils = {
         const encodedMetadataHex = ethUtil.bufferToHex(encodedMetadata);
         return encodedMetadataHex;
     },
-    decodeERC20ProxyData(proxyData: string): string /* tokenAddress */ {
+    decodeERC20ProxyData(proxyData: string): ERC20ProxyData {
         const encodedProxyMetadata = ethUtil.toBuffer(proxyData);
         if (encodedProxyMetadata.byteLength !== 21) {
             throw new Error(
@@ -63,7 +63,11 @@ export const assetProxyUtils = {
         }
         const encodedTokenAddress = encodedProxyMetadata.slice(1, 21);
         const tokenAddress = assetProxyUtils.decodeAddress(encodedTokenAddress);
-        return tokenAddress;
+        const erc20ProxyData = {
+            assetProxyId,
+            tokenAddress,
+        };
+        return erc20ProxyData;
     },
     encodeERC721ProxyData(tokenAddress: string, tokenId: BigNumber): string {
         const encodedAssetProxyId = assetProxyUtils.encodeAssetProxyId(AssetProxyId.ERC721);
@@ -73,7 +77,7 @@ export const assetProxyUtils = {
         const encodedMetadataHex = ethUtil.bufferToHex(encodedMetadata);
         return encodedMetadataHex;
     },
-    decodeERC721ProxyData(proxyData: string): [string /* tokenAddress */, BigNumber /* tokenId */] {
+    decodeERC721ProxyData(proxyData: string): ERC721ProxyData {
         const encodedProxyMetadata = ethUtil.toBuffer(proxyData);
         if (encodedProxyMetadata.byteLength !== 53) {
             throw new Error(
@@ -95,7 +99,12 @@ export const assetProxyUtils = {
         const tokenAddress = assetProxyUtils.decodeAddress(encodedTokenAddress);
         const encodedTokenId = encodedProxyMetadata.slice(21, 53);
         const tokenId = assetProxyUtils.decodeUint256(encodedTokenId);
-        return [tokenAddress, tokenId];
+        const erc721ProxyData = {
+            assetProxyId,
+            tokenAddress,
+            tokenId,
+        };
+        return erc721ProxyData;
     },
     decodeProxyDataId(proxyData: string): AssetProxyId {
         const encodedProxyMetadata = ethUtil.toBuffer(proxyData);
@@ -110,4 +119,26 @@ export const assetProxyUtils = {
         const assetProxyId = assetProxyUtils.decodeAssetProxyId(encodedAssetProxyId);
         return assetProxyId;
     },
+    decodeProxyData(proxyData: string): ProxyData {
+        const assetProxyId = assetProxyUtils.decodeProxyDataId(proxyData);
+        switch (assetProxyId) {
+            case AssetProxyId.ERC20:
+                const erc20ProxyData = assetProxyUtils.decodeERC20ProxyData(proxyData);
+                const generalizedERC20ProxyData = {
+                    assetProxyId,
+                    tokenAddress: erc20ProxyData.tokenAddress,
+                };
+                return generalizedERC20ProxyData;
+            case AssetProxyId.ERC721:
+                const erc721ProxyData = assetProxyUtils.decodeERC721ProxyData(proxyData);
+                const generaliedERC721ProxyData = {
+                    assetProxyId,
+                    tokenAddress: erc721ProxyData.tokenAddress,
+                    data: erc721ProxyData.tokenId,
+                };
+                return generaliedERC721ProxyData;
+            default:
+                throw new Error(`Unrecognized asset proxy id: ${assetProxyId}`);
+        }
+    },
 };

packages/contracts/src/utils/types.ts

@@ -180,3 +180,20 @@ export interface OrderInfo {
     orderHash: string;
     orderFilledAmount: BigNumber;
 }
+
+export interface ERC20ProxyData {
+    assetProxyId: AssetProxyId;
+    tokenAddress: string;
+}
+
+export interface ERC721ProxyData {
+    assetProxyId: AssetProxyId;
+    tokenAddress: string;
+    tokenId: BigNumber;
+}
+
+export interface ProxyData {
+    assetProxyId: AssetProxyId;
+    tokenAddress?: string;
+    data?: any;
+}

packages/contracts/test/utils/match_order_tester.ts

@@ -73,7 +73,8 @@ export class MatchOrderTester {
         const makerAssetProxyIdLeft = assetProxyUtils.decodeProxyDataId(signedOrderLeft.makerAssetData);
         if (makerAssetProxyIdLeft === AssetProxyId.ERC20) {
             // Decode asset data
-            const makerAssetAddressLeft = assetProxyUtils.decodeERC20ProxyData(signedOrderLeft.makerAssetData);
+            const erc20ProxyData = assetProxyUtils.decodeERC20ProxyData(signedOrderLeft.makerAssetData);
+            const makerAssetAddressLeft = erc20ProxyData.tokenAddress;
             const takerAssetAddressRight = makerAssetAddressLeft;
             // Left Maker
             expectedNewERC20BalancesByOwner[makerAddressLeft][makerAssetAddressLeft] = expectedNewERC20BalancesByOwner[
@@ -91,11 +92,9 @@ export class MatchOrderTester {
             ][makerAssetAddressLeft].add(expectedTransferAmounts.amountReceivedByTaker);
         } else if (makerAssetProxyIdLeft === AssetProxyId.ERC721) {
             // Decode asset data
-            let makerAssetAddressLeft;
-            let makerAssetIdLeft;
-            [makerAssetAddressLeft, makerAssetIdLeft] = assetProxyUtils.decodeERC721ProxyData(
-                signedOrderLeft.makerAssetData,
-            );
+            const erc721ProxyData = assetProxyUtils.decodeERC721ProxyData(signedOrderLeft.makerAssetData);
+            const makerAssetAddressLeft = erc721ProxyData.tokenAddress;
+            const makerAssetIdLeft = erc721ProxyData.tokenId;
             const takerAssetAddressRight = makerAssetAddressLeft;
             const takerAssetIdRight = makerAssetIdLeft;
             // Left Maker
@@ -109,7 +108,8 @@ export class MatchOrderTester {
         const takerAssetProxyIdLeft = assetProxyUtils.decodeProxyDataId(signedOrderLeft.takerAssetData);
         if (takerAssetProxyIdLeft === AssetProxyId.ERC20) {
             // Decode asset data
-            const takerAssetAddressLeft = assetProxyUtils.decodeERC20ProxyData(signedOrderLeft.takerAssetData);
+            const erc20ProxyData = assetProxyUtils.decodeERC20ProxyData(signedOrderLeft.takerAssetData);
+            const takerAssetAddressLeft = erc20ProxyData.tokenAddress;
             const makerAssetAddressRight = takerAssetAddressLeft;
             // Left Maker
             expectedNewERC20BalancesByOwner[makerAddressLeft][takerAssetAddressLeft] = expectedNewERC20BalancesByOwner[
@@ -123,11 +123,9 @@ export class MatchOrderTester {
             );
         } else if (takerAssetProxyIdLeft === AssetProxyId.ERC721) {
             // Decode asset data
-            let makerAssetAddressRight;
-            let makerAssetIdRight;
-            [makerAssetAddressRight, makerAssetIdRight] = assetProxyUtils.decodeERC721ProxyData(
-                signedOrderRight.makerAssetData,
-            );
+            const erc721ProxyData = assetProxyUtils.decodeERC721ProxyData(signedOrderRight.makerAssetData);
+            const makerAssetAddressRight = erc721ProxyData.tokenAddress;
+            const makerAssetIdRight = erc721ProxyData.tokenId;
             const takerAssetAddressLeft = makerAssetAddressRight;
             const takerAssetIdLeft = makerAssetIdRight;
             // Right Maker