Uniswap-v2 合约概览

1pragma solidity =0.5.16;\n\nimport './interfaces/IUniswapV2Pair.sol';\nimport './UniswapV2ERC20.sol';\nimport './libraries/Math.sol';\nimport './libraries/UQ112x112.sol';\nimport './interfaces/IERC20.sol';\nimport './interfaces/IUniswapV2Factory.sol';\nimport './interfaces/IUniswapV2Callee.sol';
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1contract UniswapV2Pair is IUniswapV2Pair, UniswapV2ERC20 {
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1    using SafeMath  for uint;
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1    using UQ112x112 for uint224;
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1    uint public constant MINIMUM_LIQUIDITY = 10**3;
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1    bytes4 private constant SELECTOR = bytes4(keccak256(bytes('transfer(address,uint256)')));
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1    address public factory;
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1    address public token0;\n    address public token1;
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1    uint112 private reserve0;           // 使用单个存储槽，可通过 getReserves 访问\n    uint112 private reserve1;           // 使用单个存储槽，可通过 getReserves 访问
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1    uint32  private blockTimestampLast; // 使用单个存储槽，可通过 getReserves 访问
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1    uint public price0CumulativeLast;\n    uint public price1CumulativeLast;
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1    uint public kLast; // reserve0 * reserve1，截至最近一次流动性事件发生后
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1    uint private unlocked = 1;
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1    modifier lock() {
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1        require(unlocked == 1, 'UniswapV2: LOCKED');\n        unlocked = 0;
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1        _;
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1        unlocked = 1;\n    }
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1    function getReserves() public view returns (uint112 _reserve0, uint112 _reserve1, uint32 _blockTimestampLast) {\n        _reserve0 = reserve0;\n        _reserve1 = reserve1;\n        _blockTimestampLast = blockTimestampLast;\n    }
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1    function _safeTransfer(address token, address to, uint value) private {\n        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(SELECTOR, to, value));
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1        require(success && (data.length == 0 || abi.decode(data, (bool))), 'UniswapV2: TRANSFER_FAILED');\n    }
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1    event Mint(address indexed sender, uint amount0, uint amount1);\n    event Burn(address indexed sender, uint amount0, uint amount1, address indexed to);
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1    event Swap(\n        address indexed sender,\n        uint amount0In,\n        uint amount1In,\n        uint amount0Out,\n        uint amount1Out,\n        address indexed to\n    );
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1    event Sync(uint112 reserve0, uint112 reserve1);
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1    constructor() public {\n        factory = msg.sender;\n    }
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1    // 在部署时由工厂调用一次\n    function initialize(address _token0, address _token1) external {\n        require(msg.sender == factory, 'UniswapV2: FORBIDDEN'); // 检查是否充分\n        token0 = _token0;\n        token1 = _token1;\n    }
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1    // 更新储备金，并在每个区块的第一次调用时更新价格累加器\n    function _update(uint balance0, uint balance1, uint112 _reserve0, uint112 _reserve1) private {
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1        require(balance0 <= uint112(-1) && balance1 <= uint112(-1), 'UniswapV2: OVERFLOW');
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1        uint32 blockTimestamp = uint32(block.timestamp % 2**32);\n        uint32 timeElapsed = blockTimestamp - blockTimestampLast; // 期望溢出\n        if (timeElapsed > 0 && _reserve0 != 0 && _reserve1 != 0) {
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1            // * 从不溢出，+ 期望溢出\n            price0CumulativeLast += uint(UQ112x112.encode(_reserve1).uqdiv(_reserve0)) * timeElapsed;\n            price1CumulativeLast += uint(UQ112x112.encode(_reserve0).uqdiv(_reserve1)) * timeElapsed;\n        }
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1        reserve0 = uint112(balance0);\n        reserve1 = uint112(balance1);\n        blockTimestampLast = blockTimestamp;\n        emit Sync(reserve0, reserve1);\n    }
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1    // 如果开启了费用，则铸造相当于 sqrt(k) 增长的 1/6 的流动性\n    function _mintFee(uint112 _reserve0, uint112 _reserve1) private returns (bool feeOn) {
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1        address feeTo = IUniswapV2Factory(factory).feeTo();\n        feeOn = feeTo != address(0);
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1        uint _kLast = kLast; // 节省燃料
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1        if (feeOn) {\n            if (_kLast != 0) {
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1                uint rootK = Math.sqrt(uint(_reserve0).mul(_reserve1));\n                uint rootKLast = Math.sqrt(_kLast);\n                if (rootK > rootKLast) {
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1                    uint numerator = totalSupply.mul(rootK.sub(rootKLast));\n                    uint denominator = rootK.mul(5).add(rootKLast);\n                    uint liquidity = numerator / denominator;
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1                    if (liquidity > 0) _mint(feeTo, liquidity);\n                }\n            }
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1        } else if (_kLast != 0) {\n            kLast = 0;\n        }\n    }
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1    // 这个底层函数应该从一个执行重要安全检查的合约中调用\n    function mint(address to) external lock returns (uint liquidity) {
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1        (uint112 _reserve0, uint112 _reserve1,) = getReserves(); // 节省燃料
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1        uint balance0 = IERC20(token0).balanceOf(address(this));\n        uint balance1 = IERC20(token1).balanceOf(address(this));\n        uint amount0 = balance0.sub(_reserve0);\n        uint amount1 = balance1.sub(_reserve1);
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1        bool feeOn = _mintFee(_reserve0, _reserve1);
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1        uint _totalSupply = totalSupply; // 节省燃料，必须在此处定义，因为 totalSupply 可以在 _mintFee 中更新\n        if (_totalSupply == 0) {\n            liquidity = Math.sqrt(amount0.mul(amount1)).sub(MINIMUM_LIQUIDITY);\n           _mint(address(0), MINIMUM_LIQUIDITY); // 永久锁定第一个 MINIMUM_LIQUIDITY 代币
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1        } else {\n            liquidity = Math.min(amount0.mul(_totalSupply) / _reserve0, amount1.mul(_totalSupply) / _reserve1);
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1        }\n        require(liquidity > 0, 'UniswapV2: INSUFFICIENT_LIQUIDITY_MINTED');\n        _mint(to, liquidity);
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1\n        _update(balance0, balance1, _reserve0, _reserve1);\n        if (feeOn) kLast = uint(reserve0).mul(reserve1); // reserve0 和 reserve1 是最新的\n        emit Mint(msg.sender, amount0, amount1);\n    }
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1    // 这个底层函数应该从一个执行重要安全检查的合约中调用\n    function burn(address to) external lock returns (uint amount0, uint amount1) {
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1        (uint112 _reserve0, uint112 _reserve1,) = getReserves(); // 节省燃料\n        address _token0 = token0;                                // 节省燃料\n        address _token1 = token1;                                // 节省燃料\n        uint balance0 = IERC20(_token0).balanceOf(address(this));\n        uint balance1 = IERC20(_token1).balanceOf(address(this));\n        uint liquidity = balanceOf[address(this)];
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1        bool feeOn = _mintFee(_reserve0, _reserve1);\n        uint _totalSupply = totalSupply; // 节省燃料，必须在此处定义，因为 totalSupply 可以在 _mintFee 中更新\n        amount0 = liquidity.mul(balance0) / _totalSupply; // 使用余额确保按比例分配\n        amount1 = liquidity.mul(balance1) / _totalSupply; // 使用余额确保按比例分配\n        require(amount0 > 0 && amount1 > 0, 'UniswapV2: INSUFFICIENT_LIQUIDITY_BURNED');
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1        _burn(address(this), liquidity);\n        _safeTransfer(_token0, to, amount0);\n        _safeTransfer(_token1, to, amount1);\n        balance0 = IERC20(_token0).balanceOf(address(this));\n        balance1 = IERC20(_token1).balanceOf(address(this));\n\n        _update(balance0, balance1, _reserve0, _reserve1);\n        if (feeOn) kLast = uint(reserve0).mul(reserve1); // reserve0 和 reserve1 是最新的\n        emit Burn(msg.sender, amount0, amount1, to);\n    }\n
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1    // 这个底层函数应该从一个执行重要安全检查的合约中调用\n    function swap(uint amount0Out, uint amount1Out, address to, bytes calldata data) external lock {
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1        require(amount0Out > 0 || amount1Out > 0, 'UniswapV2: INSUFFICIENT_OUTPUT_AMOUNT');\n        (uint112 _reserve0, uint112 _reserve1,) = getReserves(); // 节省燃料\n        require(amount0Out < _reserve0 && amount1Out < _reserve1, 'UniswapV2: INSUFFICIENT_LIQUIDITY');\n\n        uint balance0;\n        uint balance1;\n        { // _token{0,1} 的作用域，避免堆栈过深错误
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1            address _token0 = token0;\n            address _token1 = token1;\n            require(to != _token0 && to != _token1, 'UniswapV2: INVALID_TO');\n            if (amount0Out > 0) _safeTransfer(_token0, to, amount0Out); // 乐观地转移代币\n            if (amount1Out > 0) _safeTransfer(_token1, to, amount1Out); // 乐观地转移代币
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1            if (data.length > 0) IUniswapV2Callee(to).uniswapV2Call(msg.sender, amount0Out, amount1Out, data);
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1            balance0 = IERC20(_token0).balanceOf(address(this));\n            balance1 = IERC20(_token1).balanceOf(address(this));\n        }
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1        uint amount0In = balance0 > _reserve0 - amount0Out ? balance0 - (_reserve0 - amount0Out) : 0;\n        uint amount1In = balance1 > _reserve1 - amount1Out ? balance1 - (_reserve1 - amount1Out) : 0;\n        require(amount0In > 0 || amount1In > 0, 'UniswapV2: INSUFFICIENT_INPUT_AMOUNT');\n        { // reserve{0,1}Adjusted 的作用域，避免堆栈过深错误\n            uint balance0Adjusted = balance0.mul(1000).sub(amount0In.mul(3));\n            uint balance1Adjusted = balance1.mul(1000).sub(amount1In.mul(3));\n            require(balance0Adjusted.mul(balance1Adjusted) >= uint(_reserve0).mul(_reserve1).mul(1000**2), 'UniswapV2: K');
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1        }\n\n        _update(balance0, balance1, _reserve0, _reserve1);\n        emit Swap(msg.sender, amount0In, amount1In, amount0Out, amount1Out, to);\n    }
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1    // 强制余额与储备金匹配\n    function skim(address to) external lock {\n        address _token0 = token0; // 节省燃料\n        address _token1 = token1; // 节省燃料\n        _safeTransfer(_token0, to, IERC20(_token0).balanceOf(address(this)).sub(reserve0));\n        _safeTransfer(_token1, to, IERC20(_token1).balanceOf(address(this)).sub(reserve1));\n    }\n\n\n\n    // 强制储备金与余额匹配\n    function sync() external lock {\n        _update(IERC20(token0).balanceOf(address(this)), IERC20(token1).balanceOf(address(this)), reserve0, reserve1);\n    }\n}
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1pragma solidity =0.5.16;\n\nimport './interfaces/IUniswapV2Factory.sol';\nimport './UniswapV2Pair.sol';\n\ncontract UniswapV2Factory is IUniswapV2Factory {\n    address public feeTo;\n    address public feeToSetter;
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1    mapping(address => mapping(address => address)) public getPair;\n    address[] public allPairs;
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1    event PairCreated(address indexed token0, address indexed token1, address pair, uint);
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1    constructor(address _feeToSetter) public {\n        feeToSetter = _feeToSetter;\n    }
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1    function allPairsLength() external view returns (uint) {\n        return allPairs.length;\n    }
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1    function createPair(address tokenA, address tokenB) external returns (address pair) {
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1        require(tokenA != tokenB, 'UniswapV2: IDENTICAL_ADDRESSES');\n        (address token0, address token1) = tokenA < tokenB ? (tokenA, tokenB) : (tokenB, tokenA);
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1        require(token0 != address(0), 'UniswapV2: ZERO_ADDRESS');\n        require(getPair[token0][token1] == address(0), 'UniswapV2: PAIR_EXISTS'); // 单次检查就足够了
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1        bytes memory bytecode = type(UniswapV2Pair).creationCode;
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1        bytes32 salt = keccak256(abi.encodePacked(token0, token1));\n        assembly {\n            pair := create2(0, add(bytecode, 32), mload(bytecode), salt)\n        }
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1        IUniswapV2Pair(pair).initialize(token0, token1);
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1        getPair[token0][token1] = pair;\n        getPair[token1][token0] = pair; // 反向填充映射\n        allPairs.push(pair);\n        emit PairCreated(token0, token1, pair, allPairs.length);
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1    function setFeeTo(address _feeTo) external {\n        require(msg.sender == feeToSetter, 'UniswapV2: FORBIDDEN');\n        feeTo = _feeTo;\n    }\n\n    function setFeeToSetter(address _feeToSetter) external {\n        require(msg.sender == feeToSetter, 'UniswapV2: FORBIDDEN');\n        feeToSetter = _feeToSetter;\n    }\n}
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1    bytes32 public DOMAIN_SEPARATOR;\n    // keccak256("Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)");\n    bytes32 public constant PERMIT_TYPEHASH = 0x6e71edae12b1b97f4d1f60370fef10105fa2faae0126114a169c64845d6126c9;
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1    mapping(address => uint) public nonces;
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1    constructor() public {\n        uint chainId;\n        assembly {\n            chainId := chainid\n        }
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1        DOMAIN_SEPARATOR = keccak256(\n            abi.encode(\n                keccak256('EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)'),\n                keccak256(bytes(name)),\n                keccak256(bytes('1')),\n                chainId,\n                address(this)\n            )\n        );\n    }
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1    function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external {
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1        require(deadline >= block.timestamp, 'UniswapV2: EXPIRED');
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1        bytes32 digest = keccak256(\n            abi.encodePacked(\n                '\\x19\\x01',\n                DOMAIN_SEPARATOR,\n                keccak256(abi.encode(PERMIT_TYPEHASH, owner, spender, value, nonces[owner]++, deadline))\n            )\n        );
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1        address recoveredAddress = ecrecover(digest, v, r, s);
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1        require(recoveredAddress != address(0) && recoveredAddress == owner, 'UniswapV2: INVALID_SIGNATURE');\n        _approve(owner, spender, value);\n    }\n
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1pragma solidity =0.6.6;\n\nimport '@uniswap/v2-core/contracts/interfaces/IUniswapV2Factory.sol';\nimport '@uniswap/lib/contracts/libraries/TransferHelper.sol';\n\nimport './interfaces/IUniswapV2Router02.sol';\nimport './libraries/UniswapV2Library.sol';\nimport './libraries/SafeMath.sol';\nimport './interfaces/IERC20.sol';\nimport './interfaces/IWETH.sol';
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1contract UniswapV2Router02 is IUniswapV2Router02 {\n    using SafeMath for uint;\n\n    address public immutable override factory;\n    address public immutable override WETH;
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1    modifier ensure(uint deadline) {\n        require(deadline >= block.timestamp, 'UniswapV2Router: EXPIRED');\n        _;\n    }
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1    constructor(address _factory, address _WETH) public {\n        factory = _factory;\n        WETH = _WETH;\n    }
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1    receive() external payable {\n        assert(msg.sender == WETH); // 只接受来自 WETH 合约的回退函数的 ETH\n    }
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1\n    // **** 添加流动性 ****\n    function _addLiquidity(
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1        address tokenA,\n        address tokenB,
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1        uint amountADesired,\n        uint amountBDesired,
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1        uint amountAMin,\n        uint amountBMin
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1    ) internal virtual returns (uint amountA, uint amountB) {
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1        // 如果该交易对尚不存在，则创建它\n        if (IUniswapV2Factory(factory).getPair(tokenA, tokenB) == address(0)) {\n            IUniswapV2Factory(factory).createPair(tokenA, tokenB);\n        }
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1        (uint reserveA, uint reserveB) = UniswapV2Library.getReserves(factory, tokenA, tokenB);
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1        if (reserveA == 0 && reserveB == 0) {\n            (amountA, amountB) = (amountADesired, amountBDesired);
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1        } else {\n            uint amountBOptimal = UniswapV2Library.quote(amountADesired, reserveA, reserveB);
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1            if (amountBOptimal <= amountBDesired) {\n                require(amountBOptimal >= amountBMin, 'UniswapV2Router: INSUFFICIENT_B_AMOUNT');\n                (amountA, amountB) = (amountADesired, amountBOptimal);
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1            } else {\n                uint amountAOptimal = UniswapV2Library.quote(amountBDesired, reserveB, reserveA);\n                assert(amountAOptimal <= amountADesired);\n                require(amountAOptimal >= amountAMin, 'UniswapV2Router: INSUFFICIENT_A_AMOUNT');\n                (amountA, amountB) = (amountAOptimal, amountBDesired);
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1    function addLiquidity(\n        address tokenA,\n        address tokenB,\n        uint amountADesired,\n        uint amountBDesired,\n        uint amountAMin,\n        uint amountBMin,\n        address to,\n        uint deadline
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1    ) external virtual override ensure(deadline) returns (uint amountA, uint amountB, uint liquidity) {\n        (amountA, amountB) = _addLiquidity(tokenA, tokenB, amountADesired, amountBDesired, amountAMin, amountBMin);\n        address pair = UniswapV2Library.pairFor(factory, tokenA, tokenB);
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1        TransferHelper.safeTransferFrom(tokenA, msg.sender, pair, amountA);\n        TransferHelper.safeTransferFrom(tokenB, msg.sender, pair, amountB);
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1        liquidity = IUniswapV2Pair(pair).mint(to);\n    }
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1    function addLiquidityETH(\n        address token,\n        uint amountTokenDesired,
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1        uint amountTokenMin,\n        uint amountETHMin,\n        address to,\n        uint deadline\n    ) external virtual override payable ensure(deadline) returns (uint amountToken, uint amountETH, uint liquidity) {\n        (amountToken, amountETH) = _addLiquidity(\n            token,\n            WETH,\n            amountTokenDesired,\n            msg.value,\n            amountTokenMin,\n            amountETHMin\n        );\n        address pair = UniswapV2Library.pairFor(factory, token, WETH);\n        TransferHelper.safeTransferFrom(token, msg.sender, pair, amountToken);\n        IWETH(WETH).deposit{value: amountETH}();\n        assert(IWETH(WETH).transfer(pair, amountETH));
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1        liquidity = IUniswapV2Pair(pair).mint(to);\n        // 如果有的话，退还零散的 eth\n        if (msg.value > amountETH) TransferHelper.safeTransferETH(msg.sender, msg.value - amountETH);\n    }
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1    // **** 移除流动性 ****\n    function removeLiquidity(\n        address tokenA,\n        address tokenB,\n        uint liquidity,\n        uint amountAMin,\n        uint amountBMin,\n        address to,\n        uint deadline\n    ) public virtual override ensure(deadline) returns (uint amountA, uint amountB) {
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1        address pair = UniswapV2Library.pairFor(factory, tokenA, tokenB);\n        IUniswapV2Pair(pair).transferFrom(msg.sender, pair, liquidity); // 将流动性发送到交易对\n        (uint amount0, uint amount1) = IUniswapV2Pair(pair).burn(to);
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1        (address token0,) = UniswapV2Library.sortTokens(tokenA, tokenB);
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1        (amountA, amountB) = tokenA == token0 ? (amount0, amount1) : (amount1, amount0);
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1        require(amountA >= amountAMin, 'UniswapV2Router: INSUFFICIENT_A_AMOUNT');\n        require(amountB >= amountBMin, 'UniswapV2Router: INSUFFICIENT_B_AMOUNT');\n    }
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1    function removeLiquidityETH(\n        address token,\n        uint liquidity,\n        uint amountTokenMin,\n        uint amountETHMin,\n        address to,\n        uint deadline\n    ) public virtual override ensure(deadline) returns (uint amountToken, uint amountETH) {\n        (amountToken, amountETH) = removeLiquidity(\n            token,\n            WETH,\n            liquidity,\n            amountTokenMin,\n            amountETHMin,\n            address(this),\n            deadline\n        );\n        TransferHelper.safeTransfer(token, to, amountToken);\n        IWETH(WETH).withdraw(amountETH);\n        TransferHelper.safeTransferETH(to, amountETH);\n    }
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1    function removeLiquidityWithPermit(\n        address tokenA,\n        address tokenB,\n        uint liquidity,\n        uint amountAMin,\n        uint amountBMin,\n        address to,\n        uint deadline,\n        bool approveMax, uint8 v, bytes32 r, bytes32 s\n    ) external virtual override returns (uint amountA, uint amountB) {\n        address pair = UniswapV2Library.pairFor(factory, tokenA, tokenB);\n        uint value = approveMax ? uint(-1) : liquidity;\n        IUniswapV2Pair(pair).permit(msg.sender, address(this), value, deadline, v, r, s);\n        (amountA, amountB) = removeLiquidity(tokenA, tokenB, liquidity, amountAMin, amountBMin, to, deadline);\n    }\n\n\n    function removeLiquidityETHWithPermit(\n        address token,\n        uint liquidity,\n        uint amountTokenMin,\n        uint amountETHMin,\n        address to,\n        uint deadline,\n        bool approveMax, uint8 v, bytes32 r, bytes32 s\n    ) external virtual override returns (uint amountToken, uint amountETH) {\n        address pair = UniswapV2Library.pairFor(factory, token, WETH);\n        uint value = approveMax ? uint(-1) : liquidity;\n        IUniswapV2Pair(pair).permit(msg.sender, address(this), value, deadline, v, r, s);\n        (amountToken, amountETH) = removeLiquidityETH(token, liquidity, amountTokenMin, amountETHMin, to, deadline);\n    }
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1\n    // **** 移除流动性（支持转账收费代币） ****\n    function removeLiquidityETHSupportingFeeOnTransferTokens(\n        address token,\n        uint liquidity,\n        uint amountTokenMin,\n        uint amountETHMin,\n        address to,\n        uint deadline\n    ) public virtual override ensure(deadline) returns (uint amountETH) {\n        (, amountETH) = removeLiquidity(\n            token,\n            WETH,\n            liquidity,\n            amountTokenMin,\n            amountETHMin,\n            address(this),\n            deadline\n        );\n        TransferHelper.safeTransfer(token, to, IERC20(token).balanceOf(address(this)));\n        IWETH(WETH).withdraw(amountETH);\n        TransferHelper.safeTransferETH(to, amountETH);\n    }\n
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1\n\n    function removeLiquidityETHWithPermitSupportingFeeOnTransferTokens(\n        address token,\n        uint liquidity,\n        uint amountTokenMin,\n        uint amountETHMin,\n        address to,\n        uint deadline,\n        bool approveMax, uint8 v, bytes32 r, bytes32 s\n    ) external virtual override returns (uint amountETH) {\n        address pair = UniswapV2Library.pairFor(factory, token, WETH);\n        uint value = approveMax ? uint(-1) : liquidity;\n        IUniswapV2Pair(pair).permit(msg.sender, address(this), value, deadline, v, r, s);\n        amountETH = removeLiquidityETHSupportingFeeOnTransferTokens(\n            token, liquidity, amountTokenMin, amountETHMin, to, deadline\n        );\n    }
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1    // **** 兑换 ****
2    // 要求初始金额已发送到第一个币对
3    function _swap(uint[] memory amounts, address[] memory path, address _to) internal virtual {
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1        for (uint i; i < path.length - 1; i++) {
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1            (address input, address output) = (path[i], path[i + 1]);
2            (address token0,) = UniswapV2Library.sortTokens(input, output);
3            uint amountOut = amounts[i + 1];
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1            (uint amount0Out, uint amount1Out) = input == token0 ? (uint(0), amountOut) : (amountOut, uint(0));
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1            address to = i < path.length - 2 ? UniswapV2Library.pairFor(factory, output, path[i + 2]) : _to;
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1
2            IUniswapV2Pair(UniswapV2Library.pairFor(factory, input, output)).swap(
3                amount0Out, amount1Out, to, new bytes(0)
4            );
5        }
6    }
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1    function swapExactTokensForTokens(
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1        uint amountIn,
2        uint amountOutMin,
3        address[] calldata path,
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1        address to,
2        uint deadline
3    ) external virtual override ensure(deadline) returns (uint[] memory amounts) {
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1        amounts = UniswapV2Library.getAmountsOut(factory, amountIn, path);
2        require(amounts[amounts.length - 1] >= amountOutMin, 'UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT');
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1        TransferHelper.safeTransferFrom(
2            path[0], msg.sender, UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]
3        );
4        _swap(amounts, path, to);
5    }
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1    function swapTokensForExactTokens(
2        uint amountOut,
3        uint amountInMax,
4        address[] calldata path,
5        address to,
6        uint deadline
7    ) external virtual override ensure(deadline) returns (uint[] memory amounts) {
8        amounts = UniswapV2Library.getAmountsIn(factory, amountOut, path);
9        require(amounts[0] <= amountInMax, 'UniswapV2Router: EXCESSIVE_INPUT_AMOUNT');
10        TransferHelper.safeTransferFrom(
11            path[0], msg.sender, UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]
12        );
13        _swap(amounts, path, to);
14    }
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1    function swapExactETHForTokens(uint amountOutMin, address[] calldata path, address to, uint deadline)
2        external
3        virtual
4        override
5        payable
6        ensure(deadline)
7        returns (uint[] memory amounts)
8    {
9        require(path[0] == WETH, 'UniswapV2Router: INVALID_PATH');
10        amounts = UniswapV2Library.getAmountsOut(factory, msg.value, path);
11        require(amounts[amounts.length - 1] >= amountOutMin, 'UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT');
12        IWETH(WETH).deposit{value: amounts[0]}();
13        assert(IWETH(WETH).transfer(UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]));
14        _swap(amounts, path, to);
15    }
16
17
18    function swapTokensForExactETH(uint amountOut, uint amountInMax, address[] calldata path, address to, uint deadline)
19        external
20        virtual
21        override
22        ensure(deadline)
23        returns (uint[] memory amounts)
24    {
25        require(path[path.length - 1] == WETH, 'UniswapV2Router: INVALID_PATH');
26        amounts = UniswapV2Library.getAmountsIn(factory, amountOut, path);
27        require(amounts[0] <= amountInMax, 'UniswapV2Router: EXCESSIVE_INPUT_AMOUNT');
28        TransferHelper.safeTransferFrom(
29            path[0], msg.sender, UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]
30        );
31        _swap(amounts, path, address(this));
32        IWETH(WETH).withdraw(amounts[amounts.length - 1]);
33        TransferHelper.safeTransferETH(to, amounts[amounts.length - 1]);
34    }
35
36
37
38    function swapExactTokensForETH(uint amountIn, uint amountOutMin, address[] calldata path, address to, uint deadline)
39        external
40        virtual
41        override
42        ensure(deadline)
43        returns (uint[] memory amounts)
44    {
45        require(path[path.length - 1] == WETH, 'UniswapV2Router: INVALID_PATH');
46        amounts = UniswapV2Library.getAmountsOut(factory, amountIn, path);
47        require(amounts[amounts.length - 1] >= amountOutMin, 'UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT');
48        TransferHelper.safeTransferFrom(
49            path[0], msg.sender, UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]
50        );
51        _swap(amounts, path, address(this));
52        IWETH(WETH).withdraw(amounts[amounts.length - 1]);
53        TransferHelper.safeTransferETH(to, amounts[amounts.length - 1]);
54    }
55
56
57    function swapETHForExactTokens(uint amountOut, address[] calldata path, address to, uint deadline)
58        external
59        virtual
60        override
61        payable
62        ensure(deadline)
63        returns (uint[] memory amounts)
64    {
65        require(path[0] == WETH, 'UniswapV2Router: INVALID_PATH');
66        amounts = UniswapV2Library.getAmountsIn(factory, amountOut, path);
67        require(amounts[0] <= msg.value, 'UniswapV2Router: EXCESSIVE_INPUT_AMOUNT');
68        IWETH(WETH).deposit{value: amounts[0]}();
69        assert(IWETH(WETH).transfer(UniswapV2Library.pairFor(factory, path[0], path[1]), amounts[0]));
70        _swap(amounts, path, to);
71        // 如有，退还剩余的零散 ETH
72        if (msg.value > amounts[0]) TransferHelper.safeTransferETH(msg.sender, msg.value - amounts[0]);
73    }
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1    // **** 兑换（支持转账收费的代币）****
2    // 要求初始金额已发送到第一个币对
3    function _swapSupportingFeeOnTransferTokens(address[] memory path, address _to) internal virtual {
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1        for (uint i; i < path.length - 1; i++) {
2            (address input, address output) = (path[i], path[i + 1]);
3            (address token0,) = UniswapV2Library.sortTokens(input, output);
4            IUniswapV2Pair pair = IUniswapV2Pair(UniswapV2Library.pairFor(factory, input, output));
5            uint amountInput;
6            uint amountOutput;
7            { // 作用域以避免堆栈过深错误
8            (uint reserve0, uint reserve1,) = pair.getReserves();
9            (uint reserveInput, uint reserveOutput) = input == token0 ? (reserve0, reserve1) : (reserve1, reserve0);
10            amountInput = IERC20(input).balanceOf(address(pair)).sub(reserveInput);
11            amountOutput = UniswapV2Library.getAmountOut(amountInput, reserveInput, reserveOutput);
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1            }
2            (uint amount0Out, uint amount1Out) = input == token0 ? (uint(0), amountOutput) : (amountOutput, uint(0));
3            address to = i < path.length - 2 ? UniswapV2Library.pairFor(factory, output, path[i + 2]) : _to;
4            pair.swap(amount0Out, amount1Out, to, new bytes(0));
5        }
6    }
7
8
9    function swapExactTokensForTokensSupportingFeeOnTransferTokens(
10        uint amountIn,
11        uint amountOutMin,
12        address[] calldata path,
13        address to,
14        uint deadline
15    ) external virtual override ensure(deadline) {
16        TransferHelper.safeTransferFrom(
17            path[0], msg.sender, UniswapV2Library.pairFor(factory, path[0], path[1]), amountIn
18        );
19        uint balanceBefore = IERC20(path[path.length - 1]).balanceOf(to);
20        _swapSupportingFeeOnTransferTokens(path, to);
21        require(
22            IERC20(path[path.length - 1]).balanceOf(to).sub(balanceBefore) >= amountOutMin,
23            'UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT'
24        );
25    }
26
27
28    function swapExactETHForTokensSupportingFeeOnTransferTokens(
29        uint amountOutMin,
30        address[] calldata path,
31        address to,
32        uint deadline
33    )
34        external
35        virtual
36        override
37        payable
38        ensure(deadline)
39    {
40        require(path[0] == WETH, 'UniswapV2Router: INVALID_PATH');
41        uint amountIn = msg.value;
42        IWETH(WETH).deposit{value: amountIn}();
43        assert(IWETH(WETH).transfer(UniswapV2Library.pairFor(factory, path[0], path[1]), amountIn));
44        uint balanceBefore = IERC20(path[path.length - 1]).balanceOf(to);
45        _swapSupportingFeeOnTransferTokens(path, to);
46        require(
47            IERC20(path[path.length - 1]).balanceOf(to).sub(balanceBefore) >= amountOutMin,
48            'UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT'
49        );
50    }
51
52
53    function swapExactTokensForETHSupportingFeeOnTransferTokens(
54        uint amountIn,
55        uint amountOutMin,
56        address[] calldata path,
57        address to,
58        uint deadline
59    )
60        external
61        virtual
62        override
63        ensure(deadline)
64    {
65        require(path[path.length - 1] == WETH, 'UniswapV2Router: INVALID_PATH');
66        TransferHelper.safeTransferFrom(
67            path[0], msg.sender, UniswapV2Library.pairFor(factory, path[0], path[1]), amountIn
68        );
69        _swapSupportingFeeOnTransferTokens(path, address(this));
70        uint amountOut = IERC20(WETH).balanceOf(address(this));
71        require(amountOut >= amountOutMin, 'UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT');
72        IWETH(WETH).withdraw(amountOut);
73        TransferHelper.safeTransferETH(to, amountOut);
74    }
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