Update file structure

1 files changed, 132 insertions, 0 deletions

diff --git a/packages/contracts/src/2.0.0/protocol/AssetProxy/ERC20Proxy.sol b/packages/contracts/src/2.0.0/protocol/AssetProxy/ERC20Proxy.sol
new file mode 100644
index 000000000..aed62f54f
--- /dev/null
+++ b/packages/contracts/src/2.0.0/protocol/AssetProxy/ERC20Proxy.sol
@@ -0,0 +1,132 @@
+/*
+
+  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 ^0.4.24;
+pragma experimental ABIEncoderV2;
+
+import "../../utils/LibBytes/LibBytes.sol";
+import "./MixinAuthorizable.sol";
+
+contract ERC20Proxy is
+    MixinAuthorizable
+{
+    // Id of this proxy.
+    bytes4 constant PROXY_ID = bytes4(keccak256("ERC20Token(address)"));
+    
+    function () 
+        external
+    {
+        assembly {
+            // The first 4 bytes of calldata holds the function selector
+            let selector := and(calldataload(0), 0xffffffff00000000000000000000000000000000000000000000000000000000)
+
+            // `transferFrom` will be called with the following parameters:
+            // assetData Encoded byte array.
+            // from Address to transfer asset from.
+            // to Address to transfer asset to.
+            // amount Amount of asset to transfer.
+            // bytes4(keccak256("transferFrom(bytes,address,address,uint256)")) = 0xa85e59e4
+            if eq(selector, 0xa85e59e400000000000000000000000000000000000000000000000000000000) {
+
+                // To lookup a value in a mapping, we load from the storage location keccak256(k, p),
+                // where k is the key left padded to 32 bytes and p is the storage slot
+                let start := mload(64)
+                mstore(start, and(caller, 0xffffffffffffffffffffffffffffffffffffffff))
+                mstore(add(start, 32), authorized_slot)
+
+                // Revert if authorized[msg.sender] == false
+                if iszero(sload(keccak256(start, 64))) {
+                    // Revert with `Error("SENDER_NOT_AUTHORIZED")`
+                    mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000)
+                    mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000)
+                    mstore(64, 0x0000001553454e4445525f4e4f545f415554484f52495a454400000000000000)
+                    mstore(96, 0)
+                    revert(0, 100)
+                }
+                
+                /////// Token contract address ///////
+                // The token address is found as follows:
+                // * It is stored at offset 4 in `assetData` contents.
+                // * This is stored at offset 32 from `assetData`.
+                // * The offset to `assetData` from Params is stored at offset
+                //   4 in calldata.
+                // * The offset of Params in calldata is 4.
+                // So we read location 4 and add 32 + 4 + 4 to it.
+                let token := calldataload(add(calldataload(4), 40))
+                
+                /////// Setup Header Area ///////
+                // This area holds the 4-byte `transferFrom` selector.
+                // Any trailing data in transferFromSelector will be
+                // overwritten in the next `mstore` call.
+                mstore(0, 0x23b872dd00000000000000000000000000000000000000000000000000000000)
+                
+                /////// Setup Params Area ///////
+                // We copy the fields `from`, `to` and `amount` in bulk
+                // from our own calldata to the new calldata.
+                calldatacopy(4, 36, 96)
+
+                /////// Call `token.transferFrom` using the calldata ///////
+                let success := call(
+                    gas,            // forward all gas
+                    token,          // call address of token contract
+                    0,              // don't send any ETH
+                    0,              // pointer to start of input
+                    100,            // length of input
+                    0,              // write output over input
+                    32              // output size should be 32 bytes
+                )
+
+                /////// Check return data. ///////
+                // If there is no return data, we assume the token incorrectly
+                // does not return a bool. In this case we expect it to revert
+                // on failure, which was handled above.
+                // If the token does return data, we require that it is a single
+                // nonzero 32 bytes value.
+                // So the transfer succeeded if the call succeeded and either
+                // returned nothing, or returned a non-zero 32 byte value. 
+                success := and(success, or(
+                    iszero(returndatasize),
+                    and(
+                        eq(returndatasize, 32),
+                        gt(mload(0), 0)
+                    )
+                ))
+                if success {
+                    return(0, 0)
+                }
+                
+                // Revert with `Error("TRANSFER_FAILED")`
+                mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000)
+                mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000)
+                mstore(64, 0x0000000f5452414e534645525f4641494c454400000000000000000000000000)
+                mstore(96, 0)
+                revert(0, 100)
+            }
+        }
+    }
+
+    /// @dev Gets the proxy id associated with the proxy address.
+    /// @return Proxy id.
+    function getProxyId()
+        external
+        pure
+        returns (bytes4)
+    {
+        return PROXY_ID;
+    }
+}