代币标准--ERC1155协议源码解析

ERC1155多代币标准

ERC1155结合了ERC20和ERC721的能力，这是一个标准接口，支持开发同质化的、半同质化的、非同质化的代币和其他配置的通用智能合约。

IERC1155接口

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (token/ERC1155/IERC1155.sol)

pragma solidity ^0.8.0;

import "../../utils/introspection/IERC165.sol";

// IERC1155接口同样继承了IERC165接口
interface IERC1155 is IERC165 {

TransferSingle事件

// 转移代币后触发事件，记录转移信息
    event TransferSingle(address indexed operator, address indexed from, address indexed to, uint256 id, uint256 value);

TransferBatch事件

// 批量转移代币后触发事件，记录转移信息
    event TransferBatch(
        address indexed operator,
        address indexed from,
        address indexed to,
        uint256[] ids,
        uint256[] values
    );

ApprovalForAll事件

// 授权approve后触发事件，记录授权信息
    event ApprovalForAll(address indexed account, address indexed operator, bool approved);

URI事件

// URI的值改变时触发该事件，记录信息
    event URI(string value, uint256 indexed id);

balanceOf函数

// 获取account账户对应代币id拥有的数量
    function balanceOf(address account, uint256 id) external view returns (uint256);

balanceOfBatch函数

// 获取账户列表对用的token余额，相当于多次balanceOf
    function balanceOfBatch(address[] calldata accounts, uint256[] calldata ids)
        external
        view
        returns (uint256[] memory);

setApprovalForAll函数

// 设置给operate的授权
    function setApprovalForAll(address operator, bool approved) external;

isApprovedForAll函数

// 判断operate是否有account账号的授权
    function isApprovedForAll(address account, address operator) external view returns (bool);

safeTransferFrom函数

// 从from账户转移amount数量的代币id到to地址
    function safeTransferFrom(
        address from,
        address to,
        uint256 id,
        uint256 amount,
        bytes calldata data
    ) external;

safeBatchTransferFrom函数

// 批量转移token，相当于调用多次safeTransfer
    function safeBatchTransferFrom(
        address from,
        address to,
        uint256[] calldata ids,
        uint256[] calldata amounts,
        bytes calldata data
    ) external;
}

ERC1155

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (token/ERC1155/ERC1155.sol)

pragma solidity ^0.8.0;

import "./IERC1155.sol";
import "./IERC1155Receiver.sol";
import "./extensions/IERC1155MetadataURI.sol";
import "../../utils/Address.sol";
import "../../utils/Context.sol";
import "../../utils/introspection/ERC165.sol";

contract ERC1155 is Context, ERC165, IERC1155, IERC1155MetadataURI {
    using Address for address;

    // 代币id与拥有者地址及其该代币余额的映射
    mapping(uint256 => mapping(address => uint256)) private _balances;

    // 地址之间的授权状态的映射
    mapping(address => mapping(address => bool)) private _operatorApprovals;

    // 相同类型的代币 _uri是一致的
    string private _uri;

    // 构造函数 初始化uri
    constructor(string memory uri_) {
        _setURI(uri_);
    }

supportsInterface函数

// 检查合约是否实现该接口
    function supportsInterface(bytes4 interfaceId) public view virtual override(ERC165, IERC165) returns (bool) {
        return
            interfaceId == type(IERC1155).interfaceId ||
            interfaceId == type(IERC1155MetadataURI).interfaceId ||
            super.supportsInterface(interfaceId);
    }

uri函数

// 获取代币的uri,uri指向是代币的元数据，例如图片信息
    function uri(uint256) public view virtual override returns (string memory) {
        return _uri;
    }

balanceOf函数

// 获取account地址的id代币的数量
    function balanceOf(address account, uint256 id) public view virtual override returns (uint256) {
    // 检查account不为空地址
        require(account != address(0), "ERC1155: address zero is not a valid owner");
        return _balances[id][account];
    }

balanceOfBatch函数

// 返回account账号列表对应的id代币的数量
    function balanceOfBatch(address[] memory accounts, uint256[] memory ids)
        public
        view
        virtual
        override
        returns (uint256[] memory)
    {
        // 检查账号列表长度与代币id列表长度一致
        require(accounts.length == ids.length, "ERC1155: accounts and ids length mismatch");

        // 创建一个列表长度与account相同
        uint256[] memory batchBalances = new uint256[](accounts.length);

       // 获取账号对应的代币id的数量
        for (uint256 i = 0; i < accounts.length; ++i) {
            batchBalances[i] = balanceOf(accounts[i], ids[i]);
        }

        return batchBalances;
    }

setApprovalForAll函数

// 设置对operate的授权approve状态
    function setApprovalForAll(address operator, bool approved) public virtual override {
    // 调用_setApprovalForAll函数
        _setApprovalForAll(_msgSender(), operator, approved);
    }

isApprovedForAll函数

    // 获取account地址对operate地址的授权状态
    function isApprovedForAll(address account, address operator) public view virtual override returns (bool) {
        return _operatorApprovals[account][operator];
    }

safeTransferFrom函数

// 转移mount数量的id代币 从from地址到to地址
    function safeTransferFrom(
        address from,
        address to,
        uint256 id,
        uint256 amount,
        bytes memory data
    ) public virtual override {
    // 检查from是否是合约调用者地址，或者from账号有approve授权给合约调用者
        require(
            from == _msgSender() || isApprovedForAll(from, _msgSender()),
            "ERC1155: caller is not token owner or approved"
        );
        // 调用_safeTransferFrom函数，转移代币
        _safeTransferFrom(from, to, id, amount, data);
    }

safeBatchTransferFrom函数

// 批量转移代币
    function safeBatchTransferFrom(
        address from,
        address to,
        uint256[] memory ids,
        uint256[] memory amounts,
        bytes memory data
    ) public virtual override {
        // 检查from是否是合约调用者地址，或者from账号有approve授权给合约调用者
        require(
            from == _msgSender() || isApprovedForAll(from, _msgSender()),
            "ERC1155: caller is not token owner or approved"
        );
        // 调用_safeBatchTransferFrom函数转移代币
        _safeBatchTransferFrom(from, to, ids, amounts, data);
    }

_safeTransferFrom函数

// 转移mount数量的id代币 从from地址到to地址
    function _safeTransferFrom(
        address from,
        address to,
        uint256 id,
        uint256 amount,
        bytes memory data
    ) internal virtual {
    // 检查to地址是否为空地址
        require(to != address(0), "ERC1155: transfer to the zero address");
// 获取当前合约调用者地址
        address operator = _msgSender();
        // 获取id列表，该列表只有一个元素 ids[0] = id
        uint256[] memory ids = _asSingletonArray(id);
        // 获取amount列表该列表只有一个元素 amounts[0] = amount
        uint256[] memory amounts = _asSingletonArray(amount);
        // 转移代币前执行的函数
        _beforeTokenTransfer(operator, from, to, ids, amounts, data);
        // 获取from地址的id代币数量
        uint256 fromBalance = _balances[id][from];
        // 检查 from地址的id代币数量fromBalance 是否大于等于要转移的数量amount
        require(fromBalance >= amount, "ERC1155: insufficient balance for transfer");
        // 减去转移走的数量 重新写入代币数量
        unchecked {
            _balances[id][from] = fromBalance - amount;
        }
        // 加上得到的代币数量，重新写入值
        _balances[id][to] += amount;
        // 触发转移单个代币时间，记录信息
        emit TransferSingle(operator, from, to, id, amount);
        // 代币转移后执行函数
        _afterTokenTransfer(operator, from, to, ids, amounts, data);
        // 检查接收的合约地址是否实现IERC1155Receiver接口
        _doSafeTransferAcceptanceCheck(operator, from, to, id, amount, data);
    }

_safeBatchTransferFrom函数

    function _safeBatchTransferFrom(
        address from,
        address to,
        uint256[] memory ids,
        uint256[] memory amounts,
        bytes memory data
    ) internal virtual {
    // 检查账号列表长度与代币id列表长度一致
        require(ids.length == amounts.length, "ERC1155: ids and amounts length mismatch");
    // 检查to地址是否为空地址
        require(to != address(0), "ERC1155: transfer to the zero address");
   // 获取当前合约调用者地址
        address operator = _msgSender();
  // 代币转移前执行函数
        _beforeTokenTransfer(operator, from, to, ids, amounts, data);

        for (uint256 i = 0; i < ids.length; ++i) {
        // 获取代币id
            uint256 id = ids[i];
        // 获取转移数量值
            uint256 amount = amounts[i];
        // 获取当前账号与代币对应数量
            uint256 fromBalance = _balances[id][from];
        // 检查余额是否大于转移数量
            require(fromBalance >= amount, "ERC1155: insufficient balance for transfer");
            // 减去转移数量，重新写入值
            unchecked {
                _balances[id][from] = fromBalance - amount;
            }
            // 加上转移数量，重新写入值
            _balances[id][to] += amount;
        }
    // 触发转移单个代币事件，记录信息
        emit TransferBatch(operator, from, to, ids, amounts);
    // 代币转移后执行函数
        _afterTokenTransfer(operator, from, to, ids, amounts, data);
   // 检查接收的合约地址是否实现IERC1155Receiver接口
        _doSafeBatchTransferAcceptanceCheck(operator, from, to, ids, amounts, data);
    }

_setURI函数

    // 设置新uri地址
    function _setURI(string memory newuri) internal virtual {
        _uri = newuri;
    }

_mint函数

// 铸造amount数量id代币给to地址
    function _mint(
        address to,
        uint256 id,
        uint256 amount,
        bytes memory data
    ) internal virtual {
    // 检查to是否是空地址
        require(to != address(0), "ERC1155: mint to the zero address");
   // 获取合约调用者地址
        address operator = _msgSender();
        // 获取id列表，该列表只有一个元素 ids[0] = id
        uint256[] memory ids = _asSingletonArray(id);
        // 获取amount列表该列表只有一个元素 amounts[0] = amount
        uint256[] memory amounts = _asSingletonArray(amount);
        // 代币转移前执行函数
        _beforeTokenTransfer(operator, address(0), to, ids, amounts, data);
        // 增加代币余额
        _balances[id][to] += amount;
        // 触发转移单个代币事件，记录信息
        emit TransferSingle(operator, address(0), to, id, amount);
        // 代币转移后执行函数
        _afterTokenTransfer(operator, address(0), to, ids, amounts, data);
        // 检查接收的合约地址是否实现IERC1155Receiver接口
        _doSafeTransferAcceptanceCheck(operator, address(0), to, id, amount, data);
    }

_mintBatch函数

// 铸造amounts列表对应ids列表代币给to地址
    function _mintBatch(
        address to,
        uint256[] memory ids,
        uint256[] memory amounts,
        bytes memory data
    ) internal virtual {
         // 检查to是否是空地址
        require(to != address(0), "ERC1155: mint to the zero address");
        // 检查账号列表长度与代币id列表长度一致
        require(ids.length == amounts.length, "ERC1155: ids and amounts length mismatch");
        // 获取当前合约调用者地址
        address operator = _msgSender();
        // 代币转移前执行函数
        _beforeTokenTransfer(operator, address(0), to, ids, amounts, data);
        // 增加代币余额
        for (uint256 i = 0; i < ids.length; i++) {
            _balances[ids[i]][to] += amounts[i];
        }
        // 触发转移单个代币事件，记录信息
        emit TransferBatch(operator, address(0), to, ids, amounts);
        // 代币转移后执行函数
        _afterTokenTransfer(operator, address(0), to, ids, amounts, data);
        // 检查接收的合约地址是否实现IERC1155Receiver接口
        _doSafeBatchTransferAcceptanceCheck(operator, address(0), to, ids, amounts, data);
    }

_burn函数

//销毁from地址的id代币
    function _burn(
        address from,
        uint256 id,
        uint256 amount
    ) internal virtual {
        // 检查from地址 不为空地址
        require(from != address(0), "ERC1155: burn from the zero address");
        // 获取当前合约调用者地址
        address operator = _msgSender();

        // 获取id列表，该列表只有一个元素 ids[0] = id
        uint256[] memory ids = _asSingletonArray(id);

         // 获取amount列表该列表只有一个元素 amounts[0] = amount
        uint256[] memory amounts = _asSingletonArray(amount);

        // 代币转移前执行函数
        _beforeTokenTransfer(operator, from, address(0), ids, amounts, "");

        // 获取from账号id代币余额
        uint256 fromBalance = _balances[id][from];

        // 检查余额是否大于等于销毁数量
        require(fromBalance >= amount, "ERC1155: burn amount exceeds balance");

        // 减去销毁数量，重新写入值
        unchecked {
            _balances[id][from] = fromBalance - amount;
        }
        // 触发转移单个代币事件，记录信息
        emit TransferSingle(operator, from, address(0), id, amount);
        // 代币转移后执行函数
        _afterTokenTransfer(operator, from, address(0), ids, amounts, "");
    }

_burnBatch函数

// 批量销毁地址拥有的各种id代币
    function _burnBatch(
        address from,
        uint256[] memory ids,
        uint256[] memory amounts
    ) internal virtual {
        // 检查from地址 不为空地址
        require(from != address(0), "ERC1155: burn from the zero address");
        // 检查账号列表长度与代币id列表长度一致
        require(ids.length == amounts.length, "ERC1155: ids and amounts length mismatch");
         // 获取当前合约调用者地址
        address operator = _msgSender();
        // 代币转移前执行函数
        _beforeTokenTransfer(operator, from, address(0), ids, amounts, "");
        // 销毁代币
        for (uint256 i = 0; i < ids.length; i++) {
            // 获取代币id
            uint256 id = ids[i];
            // 获取销毁数量
            uint256 amount = amounts[i];
            // 获取代币余额
            uint256 fromBalance = _balances[id][from];
            // 检查余额是否大于等于销毁数量
            require(fromBalance >= amount, "ERC1155: burn amount exceeds balance");
            // 减去转销毁量，重新写入值
            unchecked {
                _balances[id][from] = fromBalance - amount;
            }
        }
        // 触发批量转移代币事件，记录信息
        emit TransferBatch(operator, from, address(0), ids, amounts);
        // 代币转移后执行函数
        _afterTokenTransfer(operator, from, address(0), ids, amounts, "");
    }

_setApprovalForAll函数

// 设置owner对operate的授权状态
    function _setApprovalForAll(
        address owner,
        address operator,
        bool approved
    ) internal virtual {
        // 检查 owner地址和operate地址是否相同
        require(owner != operator, "ERC1155: setting approval status for self");
        // 设置对operate的授权approve状态
        _operatorApprovals[owner][operator] = approved;
        // 触发授权事件
        emit ApprovalForAll(owner, operator, approved);
    }

_beforeTokenTransfer函数

// 代币转移前函数
    function _beforeTokenTransfer(
        address operator,
        address from,
        address to,
        uint256[] memory ids,
        uint256[] memory amounts,
        bytes memory data
    ) internal virtual {}

_afterTokenTransfer函数

// 代币转移后执行函数
    function _afterTokenTransfer(
        address operator,
        address from,
        address to,
        uint256[] memory ids,
        uint256[] memory amounts,
        bytes memory data
    ) internal virtual {}

_doSafeTransferAcceptanceCheck函数

// 如果to是普通地址则返回ture,如果to是合约地址则检查该合约是否实现onERC1155Received接口
    function _doSafeTransferAcceptanceCheck(
        address operator,
        address from,
        address to,
        uint256 id,
        uint256 amount,
        bytes memory data
    ) private {
        if (to.isContract()) {
            try IERC1155Receiver(to).onERC1155Received(operator, from, id, amount, data) returns (bytes4 response) {
                if (response != IERC1155Receiver.onERC1155Received.selector) {
                    revert("ERC1155: ERC1155Receiver rejected tokens");
                }
            } catch Error(string memory reason) {
                revert(reason);
            } catch {
                revert("ERC1155: transfer to non-ERC1155Receiver implementer");
            }
        }
    }

_doSafeBatchTransferAcceptanceCheck函数

// 如果to是普通地址则返回ture,如果to是合约地址则检查该合约是否实现onERC1155Received接口
    function _doSafeBatchTransferAcceptanceCheck(
        address operator,
        address from,
        address to,
        uint256[] memory ids,
        uint256[] memory amounts,
        bytes memory data
    ) private {
        if (to.isContract()) {
            try IERC1155Receiver(to).onERC1155BatchReceived(operator, from, ids, amounts, data) returns (
                bytes4 response
            ) {
                if (response != IERC1155Receiver.onERC1155BatchReceived.selector) {
                    revert("ERC1155: ERC1155Receiver rejected tokens");
                }
            } catch Error(string memory reason) {
                revert(reason);
            } catch {
                revert("ERC1155: transfer to non-ERC1155Receiver implementer");
            }
        }
    }

_asSingletonArray函数

// 返回包含单个元素的列表
    function _asSingletonArray(uint256 element) private pure returns (uint256[] memory) {
        uint256[] memory array = new uint256[](1);
        array[0] = element;

        return array;
    }
}