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// SPDX-License-Identifier: MIT
pragma solidity 0.8.15;
import { ERC721Bridge } from "../universal/ERC721Bridge.sol";
import { IERC721 } from "@openzeppelin/contracts/token/ERC721/IERC721.sol";
import { L2ERC721Bridge } from "../L2/L2ERC721Bridge.sol";
import { Semver } from "../universal/Semver.sol";
/**
* @title L1ERC721Bridge
* @notice The L1 ERC721 bridge is a contract which works together with the L2 ERC721 bridge to
* make it possible to transfer ERC721 tokens from Ethereum to Optimism. This contract
* acts as an escrow for ERC721 tokens deposited into L2.
*/
contract L1ERC721Bridge is ERC721Bridge, Semver {
/**
* @notice Mapping of L1 token to L2 token to ID to boolean, indicating if the given L1 token
* by ID was deposited for a given L2 token.
*/
mapping(address => mapping(address => mapping(uint256 => bool))) public deposits;
/**
* @custom:semver 1.1.1
*
* @param _messenger Address of the CrossDomainMessenger on this network.
* @param _otherBridge Address of the ERC721 bridge on the other network.
*/
constructor(address _messenger, address _otherBridge)
Semver(1, 1, 1)
ERC721Bridge(_messenger, _otherBridge)
{}
/**
* @notice Completes an ERC721 bridge from the other domain and sends the ERC721 token to the
* recipient on this domain.
*
* @param _localToken Address of the ERC721 token on this domain.
* @param _remoteToken Address of the ERC721 token on the other domain.
* @param _from Address that triggered the bridge on the other domain.
* @param _to Address to receive the token on this domain.
* @param _tokenId ID of the token being deposited.
* @param _extraData Optional data to forward to L2. Data supplied here will not be used to
* execute any code on L2 and is only emitted as extra data for the
* convenience of off-chain tooling.
*/
function finalizeBridgeERC721(
address _localToken,
address _remoteToken,
address _from,
address _to,
uint256 _tokenId,
bytes calldata _extraData
) external onlyOtherBridge {
require(_localToken != address(this), "L1ERC721Bridge: local token cannot be self");
// Checks that the L1/L2 NFT pair has a token ID that is escrowed in the L1 Bridge.
require(
deposits[_localToken][_remoteToken][_tokenId] == true,
"L1ERC721Bridge: Token ID is not escrowed in the L1 Bridge"
);
// Mark that the token ID for this L1/L2 token pair is no longer escrowed in the L1
// Bridge.
deposits[_localToken][_remoteToken][_tokenId] = false;
// When a withdrawal is finalized on L1, the L1 Bridge transfers the NFT to the
// withdrawer.
IERC721(_localToken).safeTransferFrom(address(this), _to, _tokenId);
// slither-disable-next-line reentrancy-events
emit ERC721BridgeFinalized(_localToken, _remoteToken, _from, _to, _tokenId, _extraData);
}
/**
* @inheritdoc ERC721Bridge
*/
function _initiateBridgeERC721(
address _localToken,
address _remoteToken,
address _from,
address _to,
uint256 _tokenId,
uint32 _minGasLimit,
bytes calldata _extraData
) internal override {
require(_remoteToken != address(0), "L1ERC721Bridge: remote token cannot be address(0)");
// Construct calldata for _l2Token.finalizeBridgeERC721(_to, _tokenId)
bytes memory message = abi.encodeWithSelector(
L2ERC721Bridge.finalizeBridgeERC721.selector,
_remoteToken,
_localToken,
_from,
_to,
_tokenId,
_extraData
);
// Lock token into bridge
deposits[_localToken][_remoteToken][_tokenId] = true;
IERC721(_localToken).transferFrom(_from, address(this), _tokenId);
// Send calldata into L2
MESSENGER.sendMessage(OTHER_BRIDGE, message, _minGasLimit);
emit ERC721BridgeInitiated(_localToken, _remoteToken, _from, _to, _tokenId, _extraData);
}
}