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249
packages/contracts/contracts/protocol/AssetProxy/MultiAssetProxy.sol
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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. | ||
*/ | ||
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pragma solidity 0.4.24; | ||
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import "../../utils/SafeMath/SafeMath.sol"; | ||
import "../Exchange/MixinAssetProxyDispatcher.sol"; | ||
import "./MixinAuthorizable.sol"; | ||
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contract MultiAssetProxy is | ||
SafeMath, | ||
MixinAssetProxyDispatcher, | ||
MixinAuthorizable | ||
{ | ||
// Id of this proxy. | ||
bytes4 constant internal PROXY_ID = bytes4(keccak256("MultiAsset(uint256[],bytes[])")); | ||
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// 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) | ||
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// `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) { | ||
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// 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, and(caller, 0xffffffffffffffffffffffffffffffffffffffff)) | ||
mstore(32, authorized_slot) | ||
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// 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) | ||
} | ||
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// `transferFrom`. | ||
// The function is marked `external`, so no abi decodeding 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. | ||
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// Load offset to `assetData` | ||
let assetDataOffset := calldataload(4) | ||
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// 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] | | ||
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// Load offset to `amounts` | ||
// We must add 4 (function selector) + 32 (assetData len) + 4 (assetProxyId) to the assetData offset | ||
let amountsOffset := calldataload(add(assetDataOffset, 40)) | ||
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// Load offsets to `nestedAssetData` | ||
let nestedAssetDataOffset := calldataload(add(assetDataOffset, 72)) | ||
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// Load number of elements in `amounts` | ||
// We must add 4 (function selector) + 128 (4 params * 32) + 32 (assetData len) + 4 (assetProxyId) + 32 (amounts len) to the amounts offset | ||
let amountsContentsStart := add(amountsOffset, 200) | ||
let amountsLen := calldataload(sub(amountsContentsStart, 32)) | ||
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// Load number of elements in `nestedAssetData` | ||
let nestedAssetDataContentsStart := add(nestedAssetDataOffset, 200) | ||
let nestedAssetDataLen := calldataload(sub(nestedAssetDataContentsStart, 32)) | ||
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// 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) | ||
} | ||
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// 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) | ||
) | ||
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// Overwrite existing offset to `assetData` with our own | ||
mstore(4, 128) | ||
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// Load `amount` | ||
let amount := calldataload(100) | ||
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// Calculate number of bytes in `amounts` contents | ||
let amountsByteLen := mul(amountsLen, 32) | ||
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// Loop through `amounts` and `nestedAssetData`, calling `transferFrom` for each respective element | ||
for {let i := 0} lt(i, amountsByteLen) {i := add(i, 32)} { | ||
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// Calculate the total amount | ||
let amountsElement := calldataload(add(amountsContentsStart, i)) | ||
let totalAmount := mul(amountsElement, amount) | ||
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// 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) | ||
} | ||
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// Write `totalAmount` to memory | ||
mstore(100, totalAmount) | ||
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// Load offset to `nestedAssetData[i]` | ||
let nestedAssetDataElementOffset := calldataload(add(nestedAssetDataContentsStart, i)) | ||
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// Load length of `nestedAssetData[i]` | ||
let nestedAssetDataElementContentsStart := add(nestedAssetDataElementOffset, 264) | ||
let nestedAssetDataElementLen := calldataload(sub(nestedAssetDataElementContentsStart, 32)) | ||
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// 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) | ||
} | ||
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// Load AssetProxy id | ||
let assetProxyId := and(calldataload(nestedAssetDataElementContentsStart), 0xffffffff00000000000000000000000000000000000000000000000000000000) | ||
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// 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) | ||
let assetProxy := sload(keccak256(132, 64)) | ||
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// 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) | ||
} | ||
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// Copy `nestedAssetData[i]` from calldata to memory | ||
calldatacopy( | ||
132, // memory slot after `amounts[i]` | ||
nestedAssetDataElementOffset, // location of `nestedAssetData[i]` in calldata | ||
add(nestedAssetDataElementLen, 32) // `nestedAssetData[i].length` plus 32 byte length | ||
) | ||
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// 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 | ||
100, // write output over memory that won't be reused | ||
512 // reserve 512 bytes for output | ||
) | ||
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if iszero(success) { | ||
revert(100, returndatasize()) | ||
} | ||
} | ||
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// Return if no `transferFrom` calls reverted | ||
return(0, 0) | ||
} | ||
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// Revert if undefined function is called | ||
revert(0, 0) | ||
} | ||
} | ||
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/// @dev Gets the proxy id associated with the proxy address. | ||
/// @return Proxy id. | ||
function getProxyId() | ||
external | ||
pure | ||
returns (bytes4) | ||
{ | ||
return PROXY_ID; | ||
} | ||
} |
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