Implemented staking logic and ZRX vault

contracts/staking/contracts/src/MixinStake.sol

@@ -0,0 +1,94 @@
+/*
+
+  Copyright 2018 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 ^0.5.5;
+
+import "./interfaces/IStake.sol";
+import "./mixins/MStake.sol";
+import "./interfaces/IVault.sol";
+import "./libs/LibZrxToken.sol";
+import "@0x/contracts-utils/contracts/src/SafeMath.sol";
+
+
+contract MixinStake is
+    MStake,
+    IStake,
+    SafeMath
+{
+    using LibZrxToken for uint256;
+
+    // default maker id that stake is delegated to
+    bytes32 constant internal NIL_MAKER_ID = 0x0;
+
+    // mapping from Staker to Maker Id to Amount Staked
+    mapping (address => mapping (bytes32 => uint256)) delegatedStake;
+
+    // mapping from Staker to Maker Id to Amount Staked
+    mapping (address => uint256) totalStake;
+
+    // ZRX vault
+    IVault zrxVault;
+
+    constructor(address _zrxVault) public {
+        zrxVault = IVault(_zrxVault);
+    }
+
+    function stake(uint256 amount)
+        external
+        returns (uint256)
+    {
+        // sanitize input - can only stake whole tokens
+        uint256 amountOfStakeToMint = amount.roundDownToNearestWholeToken();
+
+        // deposit equivalent amount of ZRX into vault
+        zrxVault.depositFrom(msg.sender, amountOfStakeToMint);
+
+        // mint stake
+        totalStake[msg.sender] = _safeAdd(totalStake[msg.sender], amountOfStakeToMint);
+        delegatedStake[msg.sender][NIL_MAKER_ID] = _safeAdd(delegatedStake[msg.sender][NIL_MAKER_ID], amountOfStakeToMint);
+
+        // return amount of stake minted
+        return amountOfStakeToMint;
+    }
+
+    function unstake(uint256 amount)
+        external
+        returns (uint256)
+    {
+        // sanitize input - can only stake whole tokens
+        uint256 amountOfStakeToBurn = amount.roundDownToNearestWholeToken();
+
+        // burn stake
+        totalStake[msg.sender] = _safeSub(totalStake[msg.sender], amountOfStakeToBurn);
+        delegatedStake[msg.sender][NIL_MAKER_ID] = _safeSub(delegatedStake[msg.sender][NIL_MAKER_ID], amountOfStakeToBurn);
+
+        // withdraw equivalent amount of ZRX from vault
+        zrxVault.withdrawFrom(msg.sender, amountOfStakeToBurn);
+
+        // return amount of stake minted
+        return amountOfStakeToBurn;
+    }
+
+    function getStakeBalance(address owner)
+        external
+        view
+        returns (uint256)
+    {
+        return totalStake[owner];
+    }
+}

contracts/staking/contracts/src/Staking.sol

@@ -18,9 +18,15 @@
 
 pragma solidity ^0.5.9;
 
-import "./IStaking.sol";
+import "./MixinStake.sol";
 
 
-contract Staking is IStaking {
+contract Staking is
+    MixinStake
+{
+    constructor(address zrxVault)
+        public
+        MixinStake(zrxVault)
+    {}
 
 }

contracts/staking/contracts/src/interfaces/IAssetProxy.sol

@@ -0,0 +1,42 @@
+/*
+
+  Copyright 2018 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 ^0.5.5;
+
+
+contract IAssetProxy {
+    /// @dev Transfers assets. Either succeeds or throws.
+    /// @param assetData Byte array encoded for the respective asset proxy.
+    /// @param from Address to transfer asset from.
+    /// @param to Address to transfer asset to.
+    /// @param amount Amount of asset to transfer.
+    function transferFrom(
+        bytes calldata assetData,
+        address from,
+        address to,
+        uint256 amount
+    )
+        external;
+    
+    /// @dev Gets the proxy id associated with the proxy address.
+    /// @return Proxy id.
+    function getProxyId()
+        external
+        pure
+        returns (bytes4);
+}

contracts/staking/contracts/src/interfaces/IStake.sol

@@ -0,0 +1,27 @@
+/*
+
+  Copyright 2018 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 ^0.5.5;
+
+
+contract IStake
+{
+    function stake(uint256 amount) external returns (uint256);
+    function unstake(uint256 amount) external returns (uint256);
+    function getStakeBalance(address owner) external view returns (uint256);
+}

contracts/staking/contracts/src/interfaces/IVault.sol

@@ -0,0 +1,31 @@
+/*
+
+  Copyright 2018 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 ^0.5.5;
+
+
+interface IVault {
+
+    function depositFrom(address owner, uint256 amount) external;
+
+    function withdrawFrom(address owner, uint256 amount) external;
+
+    function withdrawAllFrom(address owner) external returns (uint256);
+
+    function balanceOf(address owner) external view returns (uint256);
+}

contracts/staking/contracts/src/libs/LibZrxToken.sol

@@ -0,0 +1,33 @@
+/*
+
+  Copyright 2018 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 ^0.5.5;
+
+
+library LibZrxToken {
+
+    uint256 constant internal TOKEN_MULTIPLIER = 10**18;
+
+    function roundDownToNearestWholeToken(uint256 value)
+        public
+        pure
+        returns (uint256)
+    {
+        return (value / TOKEN_MULTIPLIER) * TOKEN_MULTIPLIER;
+    }
+}

contracts/staking/contracts/src/mixins/MStake.sol

@@ -19,6 +19,8 @@
 pragma solidity ^0.5.9;
 
 
-interface IStaking {
+contract MStake
+{
+    
 
 }

contracts/staking/contracts/src/vaults/MixinVaultCore.sol

@@ -0,0 +1,66 @@
+/*
+
+  Copyright 2018 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 ^0.5.5;
+
+import "@0x/contracts-utils/contracts/src/Authorizable.sol";
+
+
+contract MixinVaultCore is
+    Authorizable
+{
+
+    address internal stakingContractAddress;
+
+    bool internal isInCatostrophicFailure;
+
+    constructor(address _stakingContractAddress) public {
+        stakingContractAddress = _stakingContractAddress;
+        isInCatostrophicFailure = false;
+    }
+
+    modifier onlyStakingContract {
+        require(
+            msg.sender == stakingContractAddress,
+            "ONLY_CALLABLE_BY_STAKING_CONTRACT"
+        );
+        _;
+    }
+
+    modifier onlyInCatostrophicFailure {
+        require(
+            isInCatostrophicFailure,
+            "ONLY_CALLABLE_IN_CATOSTROPHIC_FAILURE"
+        );
+        _;
+    }
+
+    function setStakingContractAddrsess(address _stakingContractAddress)
+        external
+        onlyOwner
+    {
+        stakingContractAddress = _stakingContractAddress;
+    }
+
+    function enterCatostrophicFailure()
+        external
+        onlyOwner
+    {
+        isInCatostrophicFailure = true;
+    }
+}

contracts/staking/contracts/src/vaults/ZrxVault.sol

@@ -0,0 +1,119 @@
+/*
+
+  Copyright 2018 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 ^0.5.5;
+
+import "../interfaces/IVault.sol";
+import "../interfaces/IAssetProxy.sol";
+import "@0x/contracts-utils/contracts/src/SafeMath.sol";
+import "./MixinVaultCore.sol";
+
+
+contract ZrxVault is
+    IVault,
+    SafeMath,
+    MixinVaultCore
+{
+
+    // mapping from Owner to ZRX balance
+    mapping (address => uint256) internal balances;
+
+    IAssetProxy internal erc20Proxy;
+
+    bytes internal zrxAssetData;
+
+    constructor(address _erc20ProxyAddress, bytes memory _zrxAssetData) public {
+        erc20Proxy = IAssetProxy(_erc20ProxyAddress);
+        zrxAssetData = _zrxAssetData;
+    }
+
+    function setErc20Proxy(address _erc20ProxyAddress)
+        external
+        onlyOwner
+    {
+        erc20Proxy = IAssetProxy(_erc20ProxyAddress);
+    }
+
+    function setZrxAssetData(bytes calldata _zrxAssetData)
+        external
+        onlyOwner
+    {
+        zrxAssetData = _zrxAssetData;
+    }
+
+    function depositFrom(address owner, uint256 amount)
+        external
+        onlyStakingContract
+    {
+        // deposit ZRX from owner
+        erc20Proxy.transferFrom(
+            zrxAssetData,
+            address(this),
+            owner,
+            amount
+        );
+
+        // update balance
+        balances[owner] = _safeAdd(balances[owner], amount);
+    }
+
+    function withdrawFrom(address owner, uint256 amount)
+        external
+        onlyStakingContract
+    {
+        _withdrawFrom(owner, amount);
+    }
+
+    function withdrawAllFrom(address owner)
+        external
+        onlyInCatostrophicFailure
+        returns (uint256)
+    {
+        // get total balance
+        uint256 totalBalance = balances[owner];
+
+        // withdraw ZRX to owner
+        _withdrawFrom(owner, totalBalance);
+        return totalBalance;
+    }
+
+    function _withdrawFrom(address owner, uint256 amount)
+        internal
+    {
+        // withdraw ZRX to owner
+        erc20Proxy.transferFrom(
+            zrxAssetData,
+            address(this),
+            owner,
+            amount
+        );
+
+        // update balance
+        // note that this call will revert if trying to withdraw more
+        // than the current balance
+        balances[owner] = _safeSub(balances[owner], amount);
+    }
+
+    function balanceOf(address owner)
+        external
+        view
+        returns (uint256)
+    {
+        return balances[owner];
+    }
+}

contracts/staking/package.json

@@ -35,7 +35,7 @@
         "compile:truffle": "truffle compile"
     },
     "config": {
-        "abis": "./generated-artifacts/@(IStaking|Staking).json",
+        "abis": "./generated-artifacts/@(LibZrxToken|MixinStake|MixinVaultCore|Staking|ZrxVault).json",
         "abis:comment": "This list is auto-generated by contracts-gen. Don't edit manually."
     },
     "repository": {

contracts/staking/src/artifacts.ts

@@ -5,6 +5,15 @@
  */
 import { ContractArtifact } from 'ethereum-types';
 
-import * as IStaking from '../generated-artifacts/IStaking.json';
+import * as LibZrxToken from '../generated-artifacts/LibZrxToken.json';
+import * as MixinStake from '../generated-artifacts/MixinStake.json';
+import * as MixinVaultCore from '../generated-artifacts/MixinVaultCore.json';
 import * as Staking from '../generated-artifacts/Staking.json';
-export const artifacts = { IStaking: IStaking as ContractArtifact, Staking: Staking as ContractArtifact };
+import * as ZrxVault from '../generated-artifacts/ZrxVault.json';
+export const artifacts = {
+    MixinStake: MixinStake as ContractArtifact,
+    Staking: Staking as ContractArtifact,
+    LibZrxToken: LibZrxToken as ContractArtifact,
+    MixinVaultCore: MixinVaultCore as ContractArtifact,
+    ZrxVault: ZrxVault as ContractArtifact,
+};

contracts/staking/src/wrappers.ts

@@ -3,5 +3,8 @@
  * Warning: This file is auto-generated by contracts-gen. Don't edit manually.
  * -----------------------------------------------------------------------------
  */
-export * from '../generated-wrappers/i_staking';
+export * from '../generated-wrappers/lib_zrx_token';
+export * from '../generated-wrappers/mixin_stake';
+export * from '../generated-wrappers/mixin_vault_core';
 export * from '../generated-wrappers/staking';
+export * from '../generated-wrappers/zrx_vault';

contracts/staking/tsconfig.json

@@ -2,6 +2,12 @@
     "extends": "../../tsconfig",
     "compilerOptions": { "outDir": "lib", "rootDir": ".", "resolveJsonModule": true },
     "include": ["./src/**/*", "./test/**/*", "./generated-wrappers/**/*"],
-    "files": ["generated-artifacts/IStaking.json", "generated-artifacts/Staking.json"],
+    "files": [
+        "generated-artifacts/LibZrxToken.json",
+        "generated-artifacts/MixinStake.json",
+        "generated-artifacts/MixinVaultCore.json",
+        "generated-artifacts/Staking.json",
+        "generated-artifacts/ZrxVault.json"
+    ],
     "exclude": ["./deploy/solc/solc_bin"]
 }