uniswap如何获得eth或erc20代币的余额

Question

uniswap如何获得eth或erc20代币的余额？我在多呼叫合约的接口代码中找不到。

Answer 1

每个ERC20令牌都有一个映射来跟踪地址的余额

mapping(address => uint) public balanceOf;

当Uniswap需要检查令牌的任何余额时，例如在UniswapV2Pair.sol中，它首先需要获得部署的令牌的地址，然后检查每个合同内部的映射

// token0 is the contract address of token0
uint balance0 = IERC20(token0).balanceOf(address(this));
// token1 is the contract address of token1
uint balance1 = IERC20(token1).balanceOf(address(this));