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ERC2771Context.sol
39 lines (32 loc) · 1.1 KB
/
ERC2771Context.sol
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// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "../utils/Context.sol";
/**
* @dev Context variant with ERC2771 support.
*/
abstract contract ERC2771Context is Context {
address private _trustedForwarder;
constructor(address trustedForwarder) {
_trustedForwarder = trustedForwarder;
}
function isTrustedForwarder(address forwarder) public view virtual returns (bool) {
return forwarder == _trustedForwarder;
}
function _msgSender() internal view virtual override returns (address sender) {
if (isTrustedForwarder(msg.sender)) {
// The assembly code is more direct than the Solidity version using `abi.decode`.
assembly {
sender := shr(96, calldataload(sub(calldatasize(), 20)))
}
} else {
return super._msgSender();
}
}
function _msgData() internal view virtual override returns (bytes calldata) {
if (isTrustedForwarder(msg.sender)) {
return msg.data[:msg.data.length - 20];
} else {
return super._msgData();
}
}
}