Defi Lending Concepts 1

returnMintCtoken.sol

pragma solidity ^0.8.13;

function mintFresh(address minter, uint mintAmount) internal returns (uint, uint) {
    uint allowed = comptroller.mintAllowed(address(this), minter, mintAmount);
    if (allowed != 0) {
        return (failOpaque(Error.COMPTROLLER_REJECTION, FailureInfo.MINT_COMPTROLLER_REJECTION, allowed), 0);
    }

    if (accrualBlockNumber != getBlockNumber()) {
        return (fail(Error.MARKET_NOT_FRESH, FailureInfo.MINT_FRESHNESS_CHECK), 0);
    }

    MintLocalVars memory vars;

    (vars.mathErr, vars.exchangeRateMantissa) = exchangeRateStoredInternal();
    if (vars.mathErr != MathError.NO_ERROR) {
        return (failOpaque(Error.MATH_ERROR, FailureInfo.MINT_EXCHANGE_RATE_READ_FAILED, uint(vars.mathErr)), 0);
    }

    vars.actualMintAmount = doTransferIn(minter, mintAmount);

    (vars.mathErr, vars.mintTokens) = divScalarByExpTruncate(vars.actualMintAmount, Exp({mantissa: vars.exchangeRateMantissa}));
    require(vars.mathErr == MathError.NO_ERROR, "MINT_EXCHANGE_CALCULATION_FAILED");


    (vars.mathErr, vars.totalSupplyNew) = addUInt(totalSupply, vars.mintTokens);
    require(vars.mathErr == MathError.NO_ERROR, "MINT_NEW_TOTAL_SUPPLY_CALCULATION_FAILED");

    (vars.mathErr, vars.accountTokensNew) = addUInt(accountTokens[minter], vars.mintTokens);
    require(vars.mathErr == MathError.NO_ERROR, "MINT_NEW_ACCOUNT_BALANCE_CALCULATION_FAILED");

    totalSupply = vars.totalSupplyNew;
    accountTokens[minter] = vars.accountTokensNew;

    emit Mint(minter, vars.actualMintAmount, vars.mintTokens);
    emit Transfer(address(this), minter, vars.mintTokens);

    return (uint(Error.NO_ERROR), vars.actualMintAmount);
}