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/*
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 "../../tokens/ERC20Token/IERC20Token.sol";
import "./libs/LibTransferErrors.sol";
contract MixinERC20Transfer is
LibBytes,
LibTransferErrors
{
/// @dev Internal version of `transferFrom`.
/// @param assetData Encoded byte array.
/// @param from Address to transfer asset from.
/// @param to Address to transfer asset to.
/// @param amount Amount of asset to transfer.
function transferFromInternal(
bytes memory assetData,
address from,
address to,
uint256 amount
)
internal
{
// Decode asset data.
address token = readAddress(assetData, 0);
// Transfer tokens.
// We do a raw call so we can check the success separate
// from the return data.
bool success = token.call(abi.encodeWithSelector(
IERC20Token(token).transferFrom.selector,
from,
to,
amount
));
require(
success,
TRANSFER_FAILED
);
// 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
// value that evaluates to true.
assembly {
if returndatasize {
success := 0
if eq(returndatasize, 32) {
// First 64 bytes of memory are reserved scratch space
returndatacopy(0, 0, 32)
success := mload(0)
}
}
}
require(
success,
TRANSFER_FAILED
);
}
}
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