/
CErc20.sol
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CErc20.sol
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pragma solidity ^0.5.16;
import "./CToken.sol";
/**
* @title Compound's CErc20 Contract
* @notice CTokens which wrap an EIP-20 underlying
* @author Compound
*/
contract CErc20 is CToken, CErc20Interface {
/**
* @notice Initialize the new money market
* @param underlying_ The address of the underlying asset
* @param comptroller_ The address of the Comptroller
* @param interestRateModel_ The address of the interest rate model
* @param initialExchangeRateMantissa_ The initial exchange rate, scaled by 1e18
* @param name_ ERC-20 name of this token
* @param symbol_ ERC-20 symbol of this token
* @param decimals_ ERC-20 decimal precision of this token
*/
function initialize(address underlying_,
ComptrollerInterface comptroller_,
InterestRateModel interestRateModel_,
uint initialExchangeRateMantissa_,
string memory name_,
string memory symbol_,
uint8 decimals_) public {
// CToken initialize does the bulk of the work
super.initialize(comptroller_, interestRateModel_, initialExchangeRateMantissa_, name_, symbol_, decimals_);
// Set underlying and sanity check it
underlying = underlying_;
EIP20Interface(underlying).totalSupply();
}
/*** User Interface ***/
/**
* @notice Sender supplies assets into the market and receives cTokens in exchange
* @dev Accrues interest whether or not the operation succeeds, unless reverted
* @param mintAmount The amount of the underlying asset to supply
* @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details)
*/
function mint(uint mintAmount) external returns (uint) {
(uint err,) = mintInternal(mintAmount);
return err;
}
/**
* @notice Sender redeems cTokens in exchange for the underlying asset
* @dev Accrues interest whether or not the operation succeeds, unless reverted
* @param redeemTokens The number of cTokens to redeem into underlying
* @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details)
*/
function redeem(uint redeemTokens) external returns (uint) {
return redeemInternal(redeemTokens);
}
/**
* @notice Sender redeems cTokens in exchange for a specified amount of underlying asset
* @dev Accrues interest whether or not the operation succeeds, unless reverted
* @param redeemAmount The amount of underlying to redeem
* @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details)
*/
function redeemUnderlying(uint redeemAmount) external returns (uint) {
return redeemUnderlyingInternal(redeemAmount);
}
/**
* @notice Sender borrows assets from the protocol to their own address
* @param borrowAmount The amount of the underlying asset to borrow
* @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details)
*/
function borrow(uint borrowAmount) external returns (uint) {
return borrowInternal(borrowAmount);
}
/**
* @notice Sender repays their own borrow
* @param repayAmount The amount to repay
* @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details)
*/
function repayBorrow(uint repayAmount) external returns (uint) {
(uint err,) = repayBorrowInternal(repayAmount);
return err;
}
/**
* @notice Sender repays a borrow belonging to borrower
* @param borrower the account with the debt being payed off
* @param repayAmount The amount to repay
* @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details)
*/
function repayBorrowBehalf(address borrower, uint repayAmount) external returns (uint) {
(uint err,) = repayBorrowBehalfInternal(borrower, repayAmount);
return err;
}
/**
* @notice The sender liquidates the borrowers collateral.
* The collateral seized is transferred to the liquidator.
* @param borrower The borrower of this cToken to be liquidated
* @param repayAmount The amount of the underlying borrowed asset to repay
* @param cTokenCollateral The market in which to seize collateral from the borrower
* @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details)
*/
function liquidateBorrow(address borrower, uint repayAmount, CTokenInterface cTokenCollateral) external returns (uint) {
(uint err,) = liquidateBorrowInternal(borrower, repayAmount, cTokenCollateral);
return err;
}
/**
* @notice The sender adds to reserves.
* @param addAmount The amount fo underlying token to add as reserves
* @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details)
*/
function _addReserves(uint addAmount) external returns (uint) {
return _addReservesInternal(addAmount);
}
/*** Safe Token ***/
/**
* @notice Gets balance of this contract in terms of the underlying
* @dev This excludes the value of the current message, if any
* @return The quantity of underlying tokens owned by this contract
*/
function getCashPrior() internal view returns (uint) {
EIP20Interface token = EIP20Interface(underlying);
return token.balanceOf(address(this));
}
/**
* @dev Similar to EIP20 transfer, except it handles a False result from `transferFrom` and reverts in that case.
* This will revert due to insufficient balance or insufficient allowance.
* This function returns the actual amount received,
* which may be less than `amount` if there is a fee attached to the transfer.
*
* Note: This wrapper safely handles non-standard ERC-20 tokens that do not return a value.
* See here: https://medium.com/coinmonks/missing-return-value-bug-at-least-130-tokens-affected-d67bf08521ca
*/
function doTransferIn(address from, uint amount) internal returns (uint) {
EIP20NonStandardInterface token = EIP20NonStandardInterface(underlying);
uint balanceBefore = EIP20Interface(underlying).balanceOf(address(this));
token.transferFrom(from, address(this), amount);
bool success;
assembly {
switch returndatasize()
case 0 { // This is a non-standard ERC-20
success := not(0) // set success to true
}
case 32 { // This is a compliant ERC-20
returndatacopy(0, 0, 32)
success := mload(0) // Set `success = returndata` of external call
}
default { // This is an excessively non-compliant ERC-20, revert.
revert(0, 0)
}
}
require(success, "TOKEN_TRANSFER_IN_FAILED");
// Calculate the amount that was *actually* transferred
uint balanceAfter = EIP20Interface(underlying).balanceOf(address(this));
require(balanceAfter >= balanceBefore, "TOKEN_TRANSFER_IN_OVERFLOW");
return balanceAfter - balanceBefore; // underflow already checked above, just subtract
}
/**
* @dev Similar to EIP20 transfer, except it handles a False success from `transfer` and returns an explanatory
* error code rather than reverting. If caller has not called checked protocol's balance, this may revert due to
* insufficient cash held in this contract. If caller has checked protocol's balance prior to this call, and verified
* it is >= amount, this should not revert in normal conditions.
*
* Note: This wrapper safely handles non-standard ERC-20 tokens that do not return a value.
* See here: https://medium.com/coinmonks/missing-return-value-bug-at-least-130-tokens-affected-d67bf08521ca
*/
function doTransferOut(address payable to, uint amount) internal {
EIP20NonStandardInterface token = EIP20NonStandardInterface(underlying);
token.transfer(to, amount);
bool success;
assembly {
switch returndatasize()
case 0 { // This is a non-standard ERC-20
success := not(0) // set success to true
}
case 32 { // This is a complaint ERC-20
returndatacopy(0, 0, 32)
success := mload(0) // Set `success = returndata` of external call
}
default { // This is an excessively non-compliant ERC-20, revert.
revert(0, 0)
}
}
require(success, "TOKEN_TRANSFER_OUT_FAILED");
}
}