diff options
Diffstat (limited to 'packages/contracts/src/contracts/current/protocol/Exchange/MixinAssetProxyDispatcher.sol')
| -rw-r--r-- | packages/contracts/src/contracts/current/protocol/Exchange/MixinAssetProxyDispatcher.sol | 110 |
1 files changed, 92 insertions, 18 deletions
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/MixinAssetProxyDispatcher.sol b/packages/contracts/src/contracts/current/protocol/Exchange/MixinAssetProxyDispatcher.sol index b8d6c0722..3203322aa 100644 --- a/packages/contracts/src/contracts/current/protocol/Exchange/MixinAssetProxyDispatcher.sol +++ b/packages/contracts/src/contracts/current/protocol/Exchange/MixinAssetProxyDispatcher.sol @@ -19,17 +19,18 @@ pragma solidity ^0.4.24; import "../../utils/Ownable/Ownable.sol"; -import "./libs/LibExchangeErrors.sol"; +import "../../utils/LibBytes/LibBytes.sol"; import "./mixins/MAssetProxyDispatcher.sol"; import "../AssetProxy/interfaces/IAssetProxy.sol"; contract MixinAssetProxyDispatcher is Ownable, - LibExchangeErrors, MAssetProxyDispatcher { + using LibBytes for bytes; + // Mapping from Asset Proxy Id's to their respective Asset Proxy - mapping (uint8 => IAssetProxy) public assetProxies; + mapping (bytes4 => IAssetProxy) public assetProxies; /// @dev Registers an asset proxy to an asset proxy id. /// An id can only be assigned to a single proxy at a given time. @@ -37,7 +38,7 @@ contract MixinAssetProxyDispatcher is /// @param newAssetProxy Address of new asset proxy to register, or 0x0 to unset assetProxyId. /// @param oldAssetProxy Existing asset proxy to overwrite, or 0x0 if assetProxyId is currently unused. function registerAssetProxy( - uint8 assetProxyId, + bytes4 assetProxyId, address newAssetProxy, address oldAssetProxy ) @@ -48,17 +49,17 @@ contract MixinAssetProxyDispatcher is address currentAssetProxy = assetProxies[assetProxyId]; require( oldAssetProxy == currentAssetProxy, - ASSET_PROXY_MISMATCH + "ASSET_PROXY_MISMATCH" ); IAssetProxy assetProxy = IAssetProxy(newAssetProxy); // Ensure that the id of newAssetProxy matches the passed in assetProxyId, unless it is being reset to 0. if (newAssetProxy != address(0)) { - uint8 newAssetProxyId = assetProxy.getProxyId(); + bytes4 newAssetProxyId = assetProxy.getProxyId(); require( newAssetProxyId == assetProxyId, - ASSET_PROXY_ID_MISMATCH + "ASSET_PROXY_ID_MISMATCH" ); } @@ -74,7 +75,7 @@ contract MixinAssetProxyDispatcher is /// @dev Gets an asset proxy. /// @param assetProxyId Id of the asset proxy. /// @return The asset proxy registered to assetProxyId. Returns 0x0 if no proxy is registered. - function getAssetProxy(uint8 assetProxyId) + function getAssetProxy(bytes4 assetProxyId) external view returns (address) @@ -83,14 +84,12 @@ contract MixinAssetProxyDispatcher is } /// @dev Forwards arguments to assetProxy and calls `transferFrom`. Either succeeds or throws. - /// @param assetData Byte array encoded for the respective asset proxy. - /// @param assetProxyId Id of assetProxy to dispach to. + /// @param assetData Byte array encoded for the asset. /// @param from Address to transfer token from. /// @param to Address to transfer token to. /// @param amount Amount of token to transfer. function dispatchTransferFrom( bytes memory assetData, - uint8 assetProxyId, address from, address to, uint256 amount @@ -99,19 +98,94 @@ contract MixinAssetProxyDispatcher is { // Do nothing if no amount should be transferred. if (amount > 0) { + // Ensure assetData length is valid + require( + assetData.length > 3, + "LENGTH_GREATER_THAN_3_REQUIRED" + ); + // Lookup assetProxy + bytes4 assetProxyId; + assembly { + assetProxyId := and(mload( + add(assetData, 32)), + 0xFFFFFFFF00000000000000000000000000000000000000000000000000000000 + ) + } IAssetProxy assetProxy = assetProxies[assetProxyId]; + // Ensure that assetProxy exists require( assetProxy != address(0), - ASSET_PROXY_DOES_NOT_EXIST + "ASSET_PROXY_DOES_NOT_EXIST" ); - // transferFrom will either succeed or throw. - assetProxy.transferFrom( - assetData, - from, - to, - amount + + // We construct calldata for the `assetProxy.transferFrom` ABI. + // The layout of this calldata is in the table below. + // + // | Area | Offset | Length | Contents | + // | -------- |--------|---------|-------------------------------------------- | + // | Header | 0 | 4 | function selector | + // | Params | | 4 * 32 | function parameters: | + // | | 4 | | 1. offset to assetData (*) | + // | | 36 | | 2. from | + // | | 68 | | 3. to | + // | | 100 | | 4. amount | + // | Data | | | assetData: | + // | | 132 | 32 | assetData Length | + // | | 164 | ** | assetData Contents | + + bytes4 transferFromSelector = IAssetProxy(assetProxy).transferFrom.selector; + bool success; + assembly { + /////// Setup State /////// + // `cdStart` is the start of the calldata for `assetProxy.transferFrom` (equal to free memory ptr). + let cdStart := mload(64) + // `dataAreaLength` is the total number of words needed to store `assetData` + // As-per the ABI spec, this value is padded up to the nearest multiple of 32, + // and includes 32-bytes for length. + let dataAreaLength := and(add(mload(assetData), 63), 0xFFFFFFFFFFFE0) + // `cdEnd` is the end of the calldata for `assetProxy.transferFrom`. + let cdEnd := add(cdStart, add(132, dataAreaLength)) + + + /////// Setup Header Area /////// + // This area holds the 4-byte `transferFromSelector`. + mstore(cdStart, transferFromSelector) + + /////// Setup Params Area /////// + // Each parameter is padded to 32-bytes. The entire Params Area is 128 bytes. + // Notes: + // 1. The offset to `assetData` is the length of the Params Area (128 bytes). + // 2. A 20-byte mask is applied to addresses to zero-out the unused bytes. + mstore(add(cdStart, 4), 128) + mstore(add(cdStart, 36), and(from, 0xffffffffffffffffffffffffffffffffffffffff)) + mstore(add(cdStart, 68), and(to, 0xffffffffffffffffffffffffffffffffffffffff)) + mstore(add(cdStart, 100), amount) + + /////// Setup Data Area /////// + // This area holds `assetData`. + let dataArea := add(cdStart, 132) + for {} lt(dataArea, cdEnd) {} { + mstore(dataArea, mload(assetData)) + dataArea := add(dataArea, 32) + assetData := add(assetData, 32) + } + + /////// Call `assetProxy.transferFrom` using the constructed calldata /////// + success := call( + gas, // forward all gas + assetProxy, // call address of asset proxy + 0, // don't send any ETH + cdStart, // pointer to start of input + sub(cdEnd, cdStart), // length of input + cdStart, // write output over input + 0 // output size is 0 bytes + ) + } + require( + success, + "TRANSFER_FAILED" ); } } |