// SPDX-License-Identifier: MIT // OpenZeppelin Contracts (last updated v4.7.0) (metatx/ERC2771Context.sol) pragma solidity ^0.8.20; import {Context} from "../utils/Context.sol"; /** * @dev Context variant with ERC2771 support. * * WARNING: Avoid using this pattern in contracts that rely in a specific calldata length as they'll * be affected by any forwarder whose `msg.data` is suffixed with the `from` address according to the ERC2771 * specification adding the address size in bytes (20) to the calldata size. An example of an unexpected * behavior could be an unintended fallback (or another function) invocation while trying to invoke the `receive` * function only accessible if `msg.data.length == 0`. */ abstract contract ERC2771Context is Context { /// @custom:oz-upgrades-unsafe-allow state-variable-immutable address private immutable _trustedForwarder; /** * @dev Initializes the contract with a trusted forwarder, which will be able to * invoke functions on this contract on behalf of other accounts. * * NOTE: The trusted forwarder can be replaced by overriding {trustedForwarder}. */ /// @custom:oz-upgrades-unsafe-allow constructor constructor(address trustedForwarder_) { _trustedForwarder = trustedForwarder_; } /** * @dev Returns the address of the trusted forwarder. */ function trustedForwarder() public view virtual returns (address) { return _trustedForwarder; } /** * @dev Indicates whether any particular address is the trusted forwarder. */ function isTrustedForwarder(address forwarder) public view virtual returns (bool) { return forwarder == trustedForwarder(); } /** * @dev Override for `msg.sender`. Defaults to the original `msg.sender` whenever * a call is not performed by the trusted forwarder or the calldata length is less than * 20 bytes (an address length). */ function _msgSender() internal view virtual override returns (address sender) { if (isTrustedForwarder(msg.sender) && msg.data.length >= 20) { // The assembly code is more direct than the Solidity version using `abi.decode`. /// @solidity memory-safe-assembly assembly { sender := shr(96, calldataload(sub(calldatasize(), 20))) } } else { return super._msgSender(); } } /** * @dev Override for `msg.data`. Defaults to the original `msg.data` whenever * a call is not performed by the trusted forwarder or the calldata length is less than * 20 bytes (an address length). */ function _msgData() internal view virtual override returns (bytes calldata) { if (isTrustedForwarder(msg.sender) && msg.data.length >= 20) { return msg.data[:msg.data.length - 20]; } else { return super._msgData(); } } }