diff options
Diffstat (limited to 'contracts')
| -rw-r--r-- | contracts/core/contracts/protocol/AssetProxy/MultiAssetProxy.sol | 300 |
1 files changed, 300 insertions, 0 deletions
diff --git a/contracts/core/contracts/protocol/AssetProxy/MultiAssetProxy.sol b/contracts/core/contracts/protocol/AssetProxy/MultiAssetProxy.sol new file mode 100644 index 000000000..42231e73b --- /dev/null +++ b/contracts/core/contracts/protocol/AssetProxy/MultiAssetProxy.sol @@ -0,0 +1,300 @@ +/* + + 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; + +import "../Exchange/MixinAssetProxyDispatcher.sol"; +import "./MixinAuthorizable.sol"; + + +contract MultiAssetProxy is + MixinAssetProxyDispatcher, + MixinAuthorizable +{ + // Id of this proxy. + bytes4 constant internal PROXY_ID = bytes4(keccak256("MultiAsset(uint256[],bytes[])")); + + // solhint-disable-next-line payable-fallback + 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 + mstore(0, caller) + mstore(32, authorized_slot) + + // Revert if authorized[msg.sender] == false + if iszero(sload(keccak256(0, 64))) { + // Revert with `Error("SENDER_NOT_AUTHORIZED")` + mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000) + mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000) + mstore(64, 0x0000001553454e4445525f4e4f545f415554484f52495a454400000000000000) + mstore(96, 0) + revert(0, 100) + } + + // `transferFrom`. + // The function is marked `external`, so no abi decoding is done for + // us. Instead, we expect the `calldata` memory to contain the + // following: + // + // | 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 | + // + // (*): offset is computed from start of function parameters, so offset + // by an additional 4 bytes in the calldata. + // + // (**): see table below to compute length of assetData Contents + // + // WARNING: The ABIv2 specification allows additional padding between + // the Params and Data section. This will result in a larger + // offset to assetData. + + // Load offset to `assetData` + let assetDataOffset := calldataload(4) + + // Asset data itself is encoded as follows: + // + // | Area | Offset | Length | Contents | + // |----------|-------------|---------|-------------------------------------| + // | Header | 0 | 4 | assetProxyId | + // | Params | | 2 * 32 | function parameters: | + // | | 4 | | 1. offset to amounts (*) | + // | | 36 | | 2. offset to nestedAssetData (*) | + // | Data | | | amounts: | + // | | 68 | 32 | amounts Length | + // | | 100 | a | amounts Contents | + // | | | | nestedAssetData: | + // | | 100 + a | 32 | nestedAssetData Length | + // | | 132 + a | b | nestedAssetData Contents (offsets) | + // | | 132 + a + b | | nestedAssetData[0, ..., len] | + + // In order to find the offset to `amounts`, we must add: + // 4 (function selector) + // + assetDataOffset + // + 32 (assetData len) + // + 4 (assetProxyId) + let amountsOffset := calldataload(add(assetDataOffset, 40)) + + // In order to find the offset to `nestedAssetData`, we must add: + // 4 (function selector) + // + assetDataOffset + // + 32 (assetData len) + // + 4 (assetProxyId) + // + 32 (amounts offset) + let nestedAssetDataOffset := calldataload(add(assetDataOffset, 72)) + + // In order to find the start of the `amounts` contents, we must add: + // 4 (function selector) + // + assetDataOffset + // + 32 (assetData len) + // + 4 (assetProxyId) + // + amountsOffset + // + 32 (amounts len) + let amountsContentsStart := add(assetDataOffset, add(amountsOffset, 72)) + + // Load number of elements in `amounts` + let amountsLen := calldataload(sub(amountsContentsStart, 32)) + + // In order to find the start of the `nestedAssetData` contents, we must add: + // 4 (function selector) + // + assetDataOffset + // + 32 (assetData len) + // + 4 (assetProxyId) + // + nestedAssetDataOffset + // + 32 (nestedAssetData len) + let nestedAssetDataContentsStart := add(assetDataOffset, add(nestedAssetDataOffset, 72)) + + // Load number of elements in `nestedAssetData` + let nestedAssetDataLen := calldataload(sub(nestedAssetDataContentsStart, 32)) + + // Revert if number of elements in `amounts` differs from number of elements in `nestedAssetData` + if iszero(eq(amountsLen, nestedAssetDataLen)) { + // Revert with `Error("LENGTH_MISMATCH")` + mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000) + mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000) + mstore(64, 0x0000000f4c454e4754485f4d49534d4154434800000000000000000000000000) + mstore(96, 0) + revert(0, 100) + } + + // Copy `transferFrom` selector, offset to `assetData`, `from`, and `to` from calldata to memory + calldatacopy( + 0, // memory can safely be overwritten from beginning + 0, // start of calldata + 100 // length of selector (4) and 3 params (32 * 3) + ) + + // Overwrite existing offset to `assetData` with our own + mstore(4, 128) + + // Load `amount` + let amount := calldataload(100) + + // Calculate number of bytes in `amounts` contents + let amountsByteLen := mul(amountsLen, 32) + + // Initialize `assetProxyId` and `assetProxy` to 0 + let assetProxyId := 0 + let assetProxy := 0 + + // Loop through `amounts` and `nestedAssetData`, calling `transferFrom` for each respective element + for {let i := 0} lt(i, amountsByteLen) {i := add(i, 32)} { + + // Calculate the total amount + let amountsElement := calldataload(add(amountsContentsStart, i)) + let totalAmount := mul(amountsElement, amount) + + // Revert if multiplication resulted in an overflow + if iszero(eq(div(totalAmount, amount), amountsElement)) { + // Revert with `Error("UINT256_OVERFLOW")` + mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000) + mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000) + mstore(64, 0x0000001055494e543235365f4f564552464c4f57000000000000000000000000) + mstore(96, 0) + revert(0, 100) + } + + // Write `totalAmount` to memory + mstore(100, totalAmount) + + // Load offset to `nestedAssetData[i]` + let nestedAssetDataElementOffset := calldataload(add(nestedAssetDataContentsStart, i)) + + // In order to find the start of the `nestedAssetData[i]` contents, we must add: + // 4 (function selector) + // + assetDataOffset + // + 32 (assetData len) + // + 4 (assetProxyId) + // + nestedAssetDataOffset + // + 32 (nestedAssetData len) + // + nestedAssetDataElementOffset + // + 32 (nestedAssetDataElement len) + let nestedAssetDataElementContentsStart := add(assetDataOffset, add(nestedAssetDataOffset, add(nestedAssetDataElementOffset, 104))) + + // Load length of `nestedAssetData[i]` + let nestedAssetDataElementLenStart := sub(nestedAssetDataElementContentsStart, 32) + let nestedAssetDataElementLen := calldataload(nestedAssetDataElementLenStart) + + // Revert if the `nestedAssetData` does not contain a 4 byte `assetProxyId` + if lt(nestedAssetDataElementLen, 4) { + // Revert with `Error("LENGTH_GREATER_THAN_3_REQUIRED")` + mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000) + mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000) + mstore(64, 0x0000001e4c454e4754485f475245415445525f5448414e5f335f524551554952) + mstore(96, 0x4544000000000000000000000000000000000000000000000000000000000000) + revert(0, 100) + } + + // Load AssetProxy id + let currentAssetProxyId := and( + calldataload(nestedAssetDataElementContentsStart), + 0xffffffff00000000000000000000000000000000000000000000000000000000 + ) + + // Only load `assetProxy` if `currentAssetProxyId` does not equal `assetProxyId` + // We do not need to check if `currentAssetProxyId` is 0 since `assetProxy` is also initialized to 0 + if iszero(eq(currentAssetProxyId, assetProxyId)) { + // Update `assetProxyId` + assetProxyId := currentAssetProxyId + // 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 + mstore(132, assetProxyId) + mstore(164, assetProxies_slot) + assetProxy := sload(keccak256(132, 64)) + } + + // Revert if AssetProxy with given id does not exist + if iszero(assetProxy) { + // Revert with `Error("ASSET_PROXY_DOES_NOT_EXIST")` + mstore(0, 0x08c379a000000000000000000000000000000000000000000000000000000000) + mstore(32, 0x0000002000000000000000000000000000000000000000000000000000000000) + mstore(64, 0x0000001a41535345545f50524f58595f444f45535f4e4f545f45584953540000) + mstore(96, 0) + revert(0, 100) + } + + // Copy `nestedAssetData[i]` from calldata to memory + calldatacopy( + 132, // memory slot after `amounts[i]` + nestedAssetDataElementLenStart, // location of `nestedAssetData[i]` in calldata + add(nestedAssetDataElementLen, 32) // `nestedAssetData[i].length` plus 32 byte length + ) + + // call `assetProxy.transferFrom` + let success := call( + gas, // forward all gas + assetProxy, // call address of asset proxy + 0, // don't send any ETH + 0, // pointer to start of input + add(164, nestedAssetDataElementLen), // length of input + 0, // write output over memory that won't be reused + 0 // don't copy output to memory + ) + + // Revert with reason given by AssetProxy if `transferFrom` call failed + if iszero(success) { + returndatacopy( + 0, // copy to memory at 0 + 0, // copy from return data at 0 + returndatasize() // copy all return data + ) + revert(0, returndatasize()) + } + } + + // Return if no `transferFrom` calls reverted + return(0, 0) + } + + // Revert if undefined function is called + revert(0, 0) + } + } + + /// @dev Gets the proxy id associated with the proxy address. + /// @return Proxy id. + function getProxyId() + external + pure + returns (bytes4) + { + return PROXY_ID; + } +} |