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通过分析代码，可以发现函数在进行了一系列的检查后，首先获取了当前 YAM 的供应量，计算此次的铸币数量，然后再调用 YAM.sol 中的 rebase 函数对 totalSupply 进行调整，也就是说 rebase 过后的对 totalSupply 的影响要在下一次调用 rebaser 合约的 rebase 函数才会生效。最后 rebase 函数调用了 afterRebase 函数。我们继续跟进 afterRebase 函数中的代码： function afterRebase( uint256 mintAmount, uint256 offPegPerc ) internal { // update uniswap UniswapPair(uniswap_pair).sync(); //SlowMist// 通过 uniswap 购买 yCRV 代币 if (mintAmount > 0) { buyReserveAndTransfer( mintAmount, offPegPerc ); } // call any extra functions //SlowMist// 社区管理调用 for (uint i = 0; i < transactions.length; i++) { Transaction storage t = transactions[i]; if (t.enabled) { bool result = externalCall(t.destination, t.data); if (!result) { emit TransactionFailed(t.destination, i, t.data); revert("Transaction Failed"); } } } }通过分析发现， afterRebase 函数主要的逻辑在 buyReserveAndTransfer 函数中，此函数用于将增发出来的代币的一部分用于到 Uniswap 中购买 yCRV 代币。跟踪 buyReserveAndTransfer 函数，代码如下： function buyReserveAndTransfer( uint256 mintAmount, uint256 offPegPerc ) internal { UniswapPair pair = UniswapPair(uniswap_pair); YAMTokenInterface yam = YAMTokenInterface(yamAddress); // get reserves (uint256 token0Reserves, uint256 token1Reserves, ) = pair.getReserves(); // check if protocol has excess yam in the reserve uint256 excess = yam.balanceOf(reservesContract); //SlowMist// 计算用于 Uniswap 中兑换的 YAM 数量 uint256 tokens_to_max_slippage = uniswapMaxSlippage(token0Reserves, token1Reserves, offPegPerc); UniVars memory uniVars = UniVars({ yamsToUni: tokens_to_max_slippage, // how many yams uniswap needs amountFromReserves: excess, // how much of yamsToUni comes from reserves mintToReserves: 0 // how much yams protocol mints to reserves }); // tries to sell all mint + excess // falls back to selling some of mint and all of excess // if all else fails, sells portion of excess // upon pair.swap, `uniswapV2Call` is called by the uniswap pair contract if (isToken0) { if (tokens_to_max_slippage > mintAmount.add(excess)) { // we already have performed a safemath check on mintAmount+excess // so we dont need to continue using it in this code path // can handle selling all of reserves and mint uint256 buyTokens = getAmountOut(mintAmount + excess, token0Reserves, token1Reserves); uniVars.yamsToUni = mintAmount + excess; uniVars.amountFromReserves = excess; // call swap using entire mint amount and excess; mint 0 to reserves pair.swap(0, buyTokens, address(this), abi.encode(uniVars)); } else { if (tokens_to_max_slippage > excess) { // uniswap can handle entire reserves uint256 buyTokens = getAmountOut(tokens_to_max_slippage, token0Reserves, token1Reserves); // swap up to slippage limit, taking entire yam reserves, and minting part of total //SlowMist// 将多余代币铸给 reserves 合约 uniVars.mintToReserves = mintAmount.sub((tokens_to_max_slippage - excess)); //SlowMist// Uniswap代币交换 pair.swap(0, buyTokens, address(this), abi.encode(uniVars)); } else { // uniswap cant handle all of excess uint256 buyTokens = getAmountOut(tokens_to_max_slippage, token0Reserves, token1Reserves); uniVars.amountFromReserves = tokens_to_max_slippage; uniVars.mintToReserves = mintAmount; // swap up to slippage limit, taking excess - remainingExcess from reserves, and minting full amount // to reserves pair.swap(0, buyTokens, address(this), abi.encode(uniVars)); } } } else { if (tokens_to_max_slippage > mintAmount.add(excess)) { // can handle all of reserves and mint uint256 buyTokens = getAmountOut(mintAmount + excess, token1Reserves, token0Reserves); uniVars.yamsToUni = mintAmount + excess; uniVars.amountFromReserves = excess; // call swap using entire mint amount and excess; mint 0 to reserves pair.swap(buyTokens, 0, address(this), abi.encode(uniVars)); } else { if (tokens_to_max_slippage > excess) { // uniswap can handle entire reserves uint256 buyTokens = getAmountOut(tokens_to_max_slippage, token1Reserves, token0Reserves); // swap up to slippage limit, taking entire yam reserves, and minting part of total //SlowMist// 增发的多余的代币给 reserves 合约 uniVars.mintToReserves = mintAmount.sub( (tokens_to_max_slippage - excess)); // swap up to slippage limit, taking entire yam reserves, and minting part of total //Slowist// 在 uniswap 中进行兑换，并最终调用 rebase 合约的 uniswapV2Call 函数 pair.swap(buyTokens, 0, address(this), abi.encode(uniVars)); } else { // uniswap cant handle all of excess uint256 buyTokens = getAmountOut(tokens_to_max_slippage, token1Reserves, token0Reserves); uniVars.amountFromReserves = tokens_to_max_slippage; uniVars.mintToReserves = mintAmount; // swap up to slippage limit, taking excess - remainingExcess from reserves, and minting full amount // to reserves pair.swap(buyTokens, 0, address(this), abi.encode(uniVars)); } } } } (责任编辑：admin) |