死磕optimism之withdraw

用户从L2StandardBridge.sol 提现

    function withdraw(
        address _l2Token,
        uint256 _amount,
        uint32 _minGasLimit,
        bytes calldata _extraData
    ) external payable virtual onlyEOA {
        _initiateWithdrawal(_l2Token, msg.sender, msg.sender, _amount, _minGasLimit, _extraData);
    }
    
    function _initiateWithdrawal(
    address _l2Token,
    address _from,
    address _to,
    uint256 _amount,
    uint32 _minGasLimit,
    bytes memory _extraData
) internal {
    if (_l2Token == Predeploys.LEGACY_ERC20_ETH) {
        _initiateBridgeETH(_from, _to, _amount, _minGasLimit, _extraData);
    } else {
        address l1Token = OptimismMintableERC20(_l2Token).l1Token();
        _initiateBridgeERC20(_l2Token, l1Token, _from, _to, _amount, _minGasLimit, _extraData);
    }
}
 
 
function _initiateBridgeERC20(
        address _localToken,
        address _remoteToken,
        address _from,
        address _to,
        uint256 _amount,
        uint32 _minGasLimit,
        bytes memory _extraData
    ) internal {
        if (_isOptimismMintableERC20(_localToken)) {
            require(
                _isCorrectTokenPair(_localToken, _remoteToken),
                "StandardBridge: wrong remote token for Optimism Mintable ERC20 local token"
            );
 
            OptimismMintableERC20(_localToken).burn(_from, _amount);
        } else {
            IERC20(_localToken).safeTransferFrom(_from, address(this), _amount);
            deposits[_localToken][_remoteToken] = deposits[_localToken][_remoteToken] + _amount;
        }
 
        // Emit the correct events. By default this will be ERC20BridgeInitiated, but child
        // contracts may override this function in order to emit legacy events as well.
        _emitERC20BridgeInitiated(_localToken, _remoteToken, _from, _to, _amount, _extraData);
 
        MESSENGER.sendMessage(
            address(OTHER_BRIDGE),
            abi.encodeWithSelector(
                this.finalizeBridgeERC20.selector,
                // Because this call will be executed on the remote chain, we reverse the order of
                // the remote and local token addresses relative to their order in the
                // finalizeBridgeERC20 function.
                _remoteToken,
                _localToken,
                _from,
                _to,
                _amount,
                _extraData
            ),
            _minGasLimit
        );
    }