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pragma solidity =0.6.6;
//导入工厂接口
import '@uniswap/v2-core/contracts/interfaces/IUniswapV2Factory.sol';
//导入TransferHelper,里面提供一些safe转账方法,以后细看
import '@uniswap/lib/contracts/libraries/TransferHelper.sol';
//导入Router02接口
import './interfaces/IUniswapV2Router02.sol';
//导入Library
import './libraries/UniswapV2Library.sol';
//SafeMath
import './libraries/SafeMath.sol';
//IERC20
import './interfaces/IERC20.sol';
//IWETH,包含deposit、withdraw、transfer
import './interfaces/IWETH.sol';
//继承接口
contract UniswapV2Router02 is IUniswapV2Router02 {
using SafeMath for uint;
//immutable表示该值为不可变量
//override表示覆盖了父函数/变量
address public immutable override factory;
address public immutable override WETH;
//提交一个deadline,函数会验证当前时间是否超过deadline,若未超过,函数继续调用
modifier ensure(uint deadline) {
require(deadline >= block.timestamp, 'UniswapV2Router: EXPIRED');
_;
}
//部署合约时,提交一个工厂地址,一个WETH地址,被合约写入状态变量,且不可更改
constructor(address _factory, address _WETH) public {
factory = _factory;
//一个兑换WETH的池子
WETH = _WETH;
}
//当调用者只传ETH,并未调用函数,并未提供信息,receive被触发
receive() external payable {
//若向本合约打钱的对象地址为WETH,验证通过
//assert用于验证内部错误
//只通过回调接收来自WETH合约的ETH
assert(msg.sender == WETH); // only accept ETH via fallback from the WETH contract
}
//增加流动性
// **** ADD LIQUIDITY ****
//提交两种代币的地址、期望的注入量、注入最小值,返回经过计算后,函数建议注入的两种代币的数量
function _addLiquidity(
address tokenA,
address tokenB,
uint amountADesired,
uint amountBDesired,
uint amountAMin,
uint amountBMin
) internal virtual returns (uint amountA, uint amountB) {
//创建一个交易对,如果它此前并不存在
// create the pair if it doesn't exist yet
if (IUniswapV2Factory(factory).getPair(tokenA, tokenB) == address(0)) {
IUniswapV2Factory(factory).createPair(tokenA, tokenB);
}
//获取交易对中两种代币的储备量,这种getReserves()里面填参数的形式是从哪里规定的?
//在Pair中的定义是不填参的
(uint reserveA, uint reserveB) = UniswapV2Library.getReserves(factory, tokenA, tokenB);
//如果交易对的代币储备量为0
if (reserveA == 0 && reserveB == 0) {
//建议的注入量即为函数调用者自己想注入的量
(amountA, amountB) = (amountADesired, amountBDesired);
}
//若交易对的代币储备量不为0
else {
//通过Library.quote()计算若按照用户的期望量注入A,B的最优注入量应该为多少
uint amountBOptimal = UniswapV2Library.quote(amountADesired, reserveA, reserveB);
//如果B的最优注入量<=B的期望注入量,说明用户的B数量足够
if (amountBOptimal <= amountBDesired) {
//保证B的最优注入量>=最小注入量
require(amountBOptimal >= amountBMin, 'UniswapV2Router: INSUFFICIENT_B_AMOUNT');
//将建议的A、B注入量进行设置
(amountA, amountB) = (amountADesired, amountBOptimal);
}
//若用户的B数量不足
else {
//计算A的最优注入量
uint amountAOptimal = UniswapV2Library.quote(amountBDesired, reserveB, reserveA);
//保证用户的A币数量足够
assert(amountAOptimal <= amountADesired);
//保证A最优注入量>=最小注入量
require(amountAOptimal >= amountAMin, 'UniswapV2Router: INSUFFICIENT_A_AMOUNT');
//返回建议的A、B注入量
(amountA, amountB) = (amountAOptimal, amountBDesired);
}
}
}
//先调用_addLiquidity()计算应该最优注入A、B量,然后真的进行交易,同时转给用户相应的流动性token
//to参数表示接收流动性代币的地址,deadline表示交易的最迟时间
//返回的参数增加了一个liquidity,表示注入流动性时,同步返给用户记录流动性的代币的数量
function addLiquidity(
address tokenA,
address tokenB,
uint amountADesired,
uint amountBDesired,
uint amountAMin,
uint amountBMin,
address to,
uint deadline
) external virtual override ensure(deadline) returns (uint amountA, uint amountB, uint liquidity) {
//先调用_addLiquidity()
(amountA, amountB) = _addLiquidity(tokenA, tokenB, amountADesired, amountBDesired, amountAMin, amountBMin);
//获取交易对的地址
address pair = UniswapV2Library.pairFor(factory, tokenA, tokenB);
//将token从用户手里传入交易对
TransferHelper.safeTransferFrom(tokenA, msg.sender, pair, amoun
本文标签: sol
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