diff options
Diffstat (limited to 'packages/contracts')
| -rw-r--r-- | packages/contracts/src/contracts/current/protocol/Exchange/MixinWrapperFunctions.sol | 84 |
1 files changed, 45 insertions, 39 deletions
diff --git a/packages/contracts/src/contracts/current/protocol/Exchange/MixinWrapperFunctions.sol b/packages/contracts/src/contracts/current/protocol/Exchange/MixinWrapperFunctions.sol index 065f56e77..512f52df6 100644 --- a/packages/contracts/src/contracts/current/protocol/Exchange/MixinWrapperFunctions.sol +++ b/packages/contracts/src/contracts/current/protocol/Exchange/MixinWrapperFunctions.sol @@ -56,35 +56,32 @@ contract MixinWrapperFunctions is public returns (bool success, uint256 takerTokenFilledAmount) { - // !!! TODO !!! Update to `Order order` parameter - // We need to call MExchangeCore.fillOrder using a delegatecall in // assembly so that we can intercept a call that throws. For this, we // need the input encoded in memory in the Ethereum ABIv2 format [1]. // - // | Offset | Length | Contents | - // |--------|--------|------------------------------| - // | 0 | 4 | function selector | - // | 4 | 160 | address[5] orderAddresses | - // | 164 | 192 | uint256[6] orderValues | - // | 356 | 32 | uint256 takerTokenFillAmount | - // | 388 | 32 | offset to signature (416) | - // | 420 | 32 | len(signature) | - // | 452 | (1) | signature | - // | (2) | (3) | padding (zero) | - // | (4) | | end of input | + // | Offset | Length | Contents | + // |--------|---------|------------------------------| + // | 0 | 4 | function selector | + // | 4 | 12 * 32 | Order order | + // | 388 | 32 | uint256 takerTokenFillAmount | + // | 420 | 32 | offset to signature (448) | + // | 452 | 32 | len(signature) | + // | 486 | (1) | signature | + // | (2) | (3) | padding (zero) | + // | (4) | | end of input | // // (1): len(signature) - // (2): 452 + len(signature) + // (2): 486 + len(signature) // (3): (32 - len(signature)) mod 32 - // (4): 452 + len(signature) + (32 - len(signature)) mod 32 + // (4): 486 + len(signature) + (32 - len(signature)) mod 32 // // [1]: https://solidity.readthedocs.io/en/develop/abi-spec.html // Allocate memory for input uint256 signatureLength = signature.length; - uint256 paddingLength = (32 - signatureLength) % 32; - uint256 inputSize = 452 + signatureLength + paddingLength; + uint256 paddingLength = (32 - signatureLength) % 32 + uint256 inputSize = 486 + signatureLength + paddingLength; bytes memory input = new bytes(inputSize); // The in memory layout of `bytes memory input` starts with @@ -106,34 +103,43 @@ contract MixinWrapperFunctions is mstore(start, FILL_ORDER_FUNCTION_SIGNATURE) } - // Write orderAddresses, orderValues, takerTokenFillAmount, - // offset to signature and len(signature) + // Use identity function precompile to cheaply copy Order struct over + // We need asssembly to access the precompile + // Note that sizeof(Order) == 12 * 32 == 384 + assembly { + delegatecall( + 51, // precompile takes 15 + 3 * numWords + 0x4, // precompile for identity function + order, // pointer to start of input + 384, // length of input + add(start, 4), // store output at offset 4 + 384 // output is 384 bytes + ) + } + + // Write offset to signature and len(signature) // It is done in assembly so we can write 32 bytes at a time. In // solidity we would have to copy one byte at a time. - // Fixed size arrays do not have the `uint256 length` prefix that - // dynamic arrays have [citation needed]. assembly { - mstore(add(start, 4), orderAddresses) // maker - mstore(add(start, 36), add(orderAddresses, 32)) // taker - mstore(add(start, 68), add(orderAddresses, 64)) // makerToken - mstore(add(start, 100), add(orderAddresses, 96)) // takerToken - mstore(add(start, 132), add(orderAddresses, 128)) // feeRecipient - mstore(add(start, 164), orderValues) // makerTokenAmount - mstore(add(start, 196), add(orderValues, 32)) // takerTokenAmount - mstore(add(start, 228), add(orderValues, 64)) // makerFee - mstore(add(start, 260), add(orderValues, 96)) // takerFee - mstore(add(start, 292), add(orderValues, 128)) // expiration - mstore(add(start, 356), takerTokenFillAmount) - mstore(add(start, 388), 416) - mstore(add(start, 420), signatureLength) + mstore(add(start, 420), 448) } - // Write signature contents and padding one byte at a time - for (uint256 i = 0; i < signatureLength; i++) { - input[452 + i] = signature[i]; + // Copy over signature length contents + assembly { + let size := add(signatureLength, 32) + delegatecall( + gas, // precompile takes 15 + 3 * numWords + 0x4, // precompile for identity function + signature, // pointer to start of input + size, // length of input + add(start, 452), // store output at offset 4 + size // output is 384 bytes + ) } - for (i = 0; i < paddingLength; i++) { - input[452 + signatureLength + i] = 0x00; + + // Write padding + for (uint256 i = 0; i < paddingLength; i++) { + input[486 + signatureLength + i] = 0x00; } // Call the function |