Files
openzeppelin-contracts/contracts/token/ERC721/ERC721Receiver.sol
2018-03-28 13:33:58 -03:00

31 lines
1.2 KiB
Solidity

pragma solidity ^0.4.18;
/**
* @title ERC721 token receiver interface
* @dev Interface for any contract that wants to support safeTransfers
* from ERC721 asset contracts.
*/
contract ERC721Receiver {
/**
* @dev Magic value to be returned upon successful reception of an NFT
* Equals to `bytes4(keccak256("onERC721Received(address,uint256,bytes)"))`,
* which can be also obtained as `ERC721Receiver(0).onERC721Received.selector`
*/
bytes4 constant ERC721_RECEIVED = 0xf0b9e5ba;
/**
* @notice Handle the receipt of an NFT
* @dev The ERC721 smart contract calls this function on the recipient
* after a `safetransfer`. This function MAY throw to revert and reject the
* transfer. This function MUST use 50,000 gas or less. Return of other
* than the magic value MUST result in the transaction being reverted.
* Note: the contract address is always the message sender.
* @param _from The sending address
* @param _tokenId The NFT identifier which is being transfered
* @param _data Additional data with no specified format
* @return `bytes4(keccak256("onERC721Received(address,uint256,bytes)"))`
*/
function onERC721Received(address _from, uint256 _tokenId, bytes _data) public returns(bytes4);
}