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JumpRateModelV3.sol
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// File: contracts/InterestRateModel.sol
pragma solidity >=0.5.16;
/**
* @title Compound's InterestRateModel Interface
* @author Compound
*/
contract InterestRateModel {
/// @notice Indicator that this is an InterestRateModel contract (for inspection)
bool public constant isInterestRateModel = true;
/**
* @notice Calculates the current borrow interest rate per block
* @param cash The total amount of cash the market has
* @param borrows The total amount of borrows the market has outstanding
* @param reserves The total amount of reserves the market has
* @return The borrow rate per block (as a percentage, and scaled by 1e18)
*/
function getBorrowRate(
uint256 cash,
uint256 borrows,
uint256 reserves
) external view returns (uint256);
/**
* @notice Calculates the current supply interest rate per block
* @param cash The total amount of cash the market has
* @param borrows The total amount of borrows the market has outstanding
* @param reserves The total amount of reserves the market has
* @param reserveFactorMantissa The current reserve factor the market has
* @return The supply rate per block (as a percentage, and scaled by 1e18)
*/
function getSupplyRate(
uint256 cash,
uint256 borrows,
uint256 reserves,
uint256 reserveFactorMantissa
) external view returns (uint256);
}
// File: contracts/SafeMath.sol
pragma solidity ^0.5.16;
// From https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/math/Math.sol
// Subject to the MIT license.
/**
* @dev Wrappers over Solidity's arithmetic operations with added overflow
* checks.
*
* Arithmetic operations in Solidity wrap on overflow. This can easily result
* in bugs, because programmers usually assume that an overflow raises an
* error, which is the standard behavior in high level programming languages.
* `SafeMath` restores this intuition by reverting the transaction when an
* operation overflows.
*
* Using this library instead of the unchecked operations eliminates an entire
* class of bugs, so it's recommended to use it always.
*/
library SafeMath {
/**
* @dev Returns the addition of two unsigned integers, reverting on overflow.
*
* Counterpart to Solidity's `+` operator.
*
* Requirements:
* - Addition cannot overflow.
*/
function add(uint256 a, uint256 b) internal pure returns (uint256) {
uint256 c = a + b;
require(c >= a, "SafeMath: addition overflow");
return c;
}
/**
* @dev Returns the addition of two unsigned integers, reverting with custom message on overflow.
*
* Counterpart to Solidity's `+` operator.
*
* Requirements:
* - Addition cannot overflow.
*/
function add(
uint256 a,
uint256 b,
string memory errorMessage
) internal pure returns (uint256) {
uint256 c = a + b;
require(c >= a, errorMessage);
return c;
}
/**
* @dev Returns the subtraction of two unsigned integers, reverting on underflow (when the result is negative).
*
* Counterpart to Solidity's `-` operator.
*
* Requirements:
* - Subtraction cannot underflow.
*/
function sub(uint256 a, uint256 b) internal pure returns (uint256) {
return sub(a, b, "SafeMath: subtraction underflow");
}
/**
* @dev Returns the subtraction of two unsigned integers, reverting with custom message on underflow (when the result is negative).
*
* Counterpart to Solidity's `-` operator.
*
* Requirements:
* - Subtraction cannot underflow.
*/
function sub(
uint256 a,
uint256 b,
string memory errorMessage
) internal pure returns (uint256) {
require(b <= a, errorMessage);
uint256 c = a - b;
return c;
}
/**
* @dev Returns the multiplication of two unsigned integers, reverting on overflow.
*
* Counterpart to Solidity's `*` operator.
*
* Requirements:
* - Multiplication cannot overflow.
*/
function mul(uint256 a, uint256 b) internal pure returns (uint256) {
// Gas optimization: this is cheaper than requiring 'a' not being zero, but the
// benefit is lost if 'b' is also tested.
// See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
if (a == 0) {
return 0;
}
uint256 c = a * b;
require(c / a == b, "SafeMath: multiplication overflow");
return c;
}
/**
* @dev Returns the multiplication of two unsigned integers, reverting on overflow.
*
* Counterpart to Solidity's `*` operator.
*
* Requirements:
* - Multiplication cannot overflow.
*/
function mul(
uint256 a,
uint256 b,
string memory errorMessage
) internal pure returns (uint256) {
// Gas optimization: this is cheaper than requiring 'a' not being zero, but the
// benefit is lost if 'b' is also tested.
// See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
if (a == 0) {
return 0;
}
uint256 c = a * b;
require(c / a == b, errorMessage);
return c;
}
/**
* @dev Returns the integer division of two unsigned integers.
* Reverts on division by zero. The result is rounded towards zero.
*
* Counterpart to Solidity's `/` operator. Note: this function uses a
* `revert` opcode (which leaves remaining gas untouched) while Solidity
* uses an invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
* - The divisor cannot be zero.
*/
function div(uint256 a, uint256 b) internal pure returns (uint256) {
return div(a, b, "SafeMath: division by zero");
}
/**
* @dev Returns the integer division of two unsigned integers.
* Reverts with custom message on division by zero. The result is rounded towards zero.
*
* Counterpart to Solidity's `/` operator. Note: this function uses a
* `revert` opcode (which leaves remaining gas untouched) while Solidity
* uses an invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
* - The divisor cannot be zero.
*/
function div(
uint256 a,
uint256 b,
string memory errorMessage
) internal pure returns (uint256) {
// Solidity only automatically asserts when dividing by 0
require(b > 0, errorMessage);
uint256 c = a / b;
// assert(a == b * c + a % b); // There is no case in which this doesn't hold
return c;
}
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* Reverts when dividing by zero.
*
* Counterpart to Solidity's `%` operator. This function uses a `revert`
* opcode (which leaves remaining gas untouched) while Solidity uses an
* invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
* - The divisor cannot be zero.
*/
function mod(uint256 a, uint256 b) internal pure returns (uint256) {
return mod(a, b, "SafeMath: modulo by zero");
}
/**
* @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
* Reverts with custom message when dividing by zero.
*
* Counterpart to Solidity's `%` operator. This function uses a `revert`
* opcode (which leaves remaining gas untouched) while Solidity uses an
* invalid opcode to revert (consuming all remaining gas).
*
* Requirements:
* - The divisor cannot be zero.
*/
function mod(
uint256 a,
uint256 b,
string memory errorMessage
) internal pure returns (uint256) {
require(b != 0, errorMessage);
return a % b;
}
}
// File: ../openzeppelin-contracts/contracts/GSN/Context.sol
pragma solidity ^0.5.0;
/*
* @dev Provides information about the current execution context, including the
* sender of the transaction and its data. While these are generally available
* via msg.sender and msg.data, they should not be accessed in such a direct
* manner, since when dealing with GSN meta-transactions the account sending and
* paying for execution may not be the actual sender (as far as an application
* is concerned).
*
* This contract is only required for intermediate, library-like contracts.
*/
contract Context {
// Empty internal constructor, to prevent people from mistakenly deploying
// an instance of this contract, which should be used via inheritance.
constructor() internal {}
// solhint-disable-previous-line no-empty-blocks
function _msgSender() internal view returns (address payable) {
return msg.sender;
}
function _msgData() internal view returns (bytes memory) {
this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
return msg.data;
}
}
// File: ../openzeppelin-contracts/contracts/ownership/Ownable.sol
pragma solidity ^0.5.0;
/**
* @dev Contract module which provides a basic access control mechanism, where
* there is an account (an owner) that can be granted exclusive access to
* specific functions.
*
* This module is used through inheritance. It will make available the modifier
* `onlyOwner`, which can be applied to your functions to restrict their use to
* the owner.
*/
contract Ownable is Context {
address private _owner;
event OwnershipTransferred(
address indexed previousOwner,
address indexed newOwner
);
/**
* @dev Initializes the contract setting the deployer as the initial owner.
*/
constructor() internal {
address msgSender = _msgSender();
_owner = msgSender;
emit OwnershipTransferred(address(0), msgSender);
}
/**
* @dev Returns the address of the current owner.
*/
function owner() public view returns (address) {
return _owner;
}
/**
* @dev Throws if called by any account other than the owner.
*/
modifier onlyOwner() {
require(isOwner(), "Ownable: caller is not the owner");
_;
}
/**
* @dev Returns true if the caller is the current owner.
*/
function isOwner() public view returns (bool) {
return _msgSender() == _owner;
}
/**
* @dev Leaves the contract without owner. It will not be possible to call
* `onlyOwner` functions anymore. Can only be called by the current owner.
*
* NOTE: Renouncing ownership will leave the contract without an owner,
* thereby removing any functionality that is only available to the owner.
*/
function renounceOwnership() public onlyOwner {
emit OwnershipTransferred(_owner, address(0));
_owner = address(0);
}
/**
* @dev Transfers ownership of the contract to a new account (`newOwner`).
* Can only be called by the current owner.
*/
function transferOwnership(address newOwner) public onlyOwner {
_transferOwnership(newOwner);
}
/**
* @dev Transfers ownership of the contract to a new account (`newOwner`).
*/
function _transferOwnership(address newOwner) internal {
require(
newOwner != address(0),
"Ownable: new owner is the zero address"
);
emit OwnershipTransferred(_owner, newOwner);
_owner = newOwner;
}
}
// File: contracts/JumpRateModelV3.sol
pragma solidity ^0.5.16;
/**
* @title Compound's JumpRateModel Contract V2
* @author Compound (modified by Dharma Labs)
* @notice Version 2 modifies Version 1 by enabling updateable parameters.
* @notice Version 3 modifies Version 2 to also be Ownable and have updatable blocksPerYear.
*/
contract JumpRateModelV3 is InterestRateModel, Ownable {
using SafeMath for uint256;
event NewInterestParams(
uint256 baseRatePerBlock,
uint256 multiplierPerBlock,
uint256 jumpMultiplierPerBlock,
uint256 kink
);
/**
* @notice The approximate number of blocks per year that is assumed by the interest rate model
*/
uint256 public blocksPerYear = 15768000;
/**
* @notice The multiplier of utilization rate that gives the slope of the interest rate
*/
uint256 public multiplierPerBlock;
/**
* @notice The base interest rate which is the y-intercept when utilization rate is 0
*/
uint256 public baseRatePerBlock;
/**
* @notice The multiplierPerBlock after hitting a specified utilization point
*/
uint256 public jumpMultiplierPerBlock;
/**
* @notice The utilization point at which the jump multiplier is applied
*/
uint256 public kink;
/**
* @notice Construct an interest rate model
* @param baseRatePerYear The approximate target base APR, as a mantissa (scaled by 1e18)
* @param multiplierPerYear The rate of increase in interest rate wrt utilization (scaled by 1e18)
* @param jumpMultiplierPerYear The multiplierPerBlock after hitting a specified utilization point
* @param kink_ The utilization point at which the jump multiplier is applied
*/
constructor(
uint256 baseRatePerYear,
uint256 multiplierPerYear,
uint256 jumpMultiplierPerYear,
uint256 kink_
) public {
updateJumpRateModelInternal(
baseRatePerYear,
multiplierPerYear,
jumpMultiplierPerYear,
kink_
);
}
/**
* @notice Update the parameters of the interest rate model (only callable by owner, i.e. Timelock)
* @param baseRatePerYear The approximate target base APR, as a mantissa (scaled by 1e18)
* @param multiplierPerYear The rate of increase in interest rate wrt utilization (scaled by 1e18)
* @param jumpMultiplierPerYear The multiplierPerBlock after hitting a specified utilization point
* @param kink_ The utilization point at which the jump multiplier is applied
*/
function updateJumpRateModel(
uint256 baseRatePerYear,
uint256 multiplierPerYear,
uint256 jumpMultiplierPerYear,
uint256 kink_
) external onlyOwner {
updateJumpRateModelInternal(
baseRatePerYear,
multiplierPerYear,
jumpMultiplierPerYear,
kink_
);
}
/**
* @notice Calculates the utilization rate of the market: `borrows / (cash + borrows - reserves)`
* @param cash The amount of cash in the market
* @param borrows The amount of borrows in the market
* @param reserves The amount of reserves in the market (currently unused)
* @return The utilization rate as a mantissa between [0, 1e18]
*/
function utilizationRate(
uint256 cash,
uint256 borrows,
uint256 reserves
) public pure returns (uint256) {
// Utilization rate is 0 when there are no borrows
if (borrows == 0) {
return 0;
}
return borrows.mul(1e18).div(cash.add(borrows).sub(reserves));
}
/**
* @notice Updates the blocksPerYear in order to make interest calculations simpler
* @param blocksPerYear_ The new estimated eth blocks per year.
*/
function updateBlocksPerYear(uint256 blocksPerYear_) external onlyOwner {
blocksPerYear = blocksPerYear_;
}
/**
* @notice Calculates the current borrow rate per block, with the error code expected by the market
* @param cash The amount of cash in the market
* @param borrows The amount of borrows in the market
* @param reserves The amount of reserves in the market
* @return The borrow rate percentage per block as a mantissa (scaled by 1e18)
*/
function getBorrowRate(
uint256 cash,
uint256 borrows,
uint256 reserves
) public view returns (uint256) {
uint256 util = utilizationRate(cash, borrows, reserves);
if (util <= kink) {
return util.mul(multiplierPerBlock).div(1e18).add(baseRatePerBlock);
} else {
uint256 normalRate =
kink.mul(multiplierPerBlock).div(1e18).add(baseRatePerBlock);
uint256 excessUtil = util.sub(kink);
return
excessUtil.mul(jumpMultiplierPerBlock).div(1e18).add(
normalRate
);
}
}
/**
* @notice Calculates the current supply rate per block
* @param cash The amount of cash in the market
* @param borrows The amount of borrows in the market
* @param reserves The amount of reserves in the market
* @param reserveFactorMantissa The current reserve factor for the market
* @return The supply rate percentage per block as a mantissa (scaled by 1e18)
*/
function getSupplyRate(
uint256 cash,
uint256 borrows,
uint256 reserves,
uint256 reserveFactorMantissa
) public view returns (uint256) {
uint256 oneMinusReserveFactor =
uint256(1e18).sub(reserveFactorMantissa);
uint256 borrowRate = getBorrowRate(cash, borrows, reserves);
uint256 rateToPool = borrowRate.mul(oneMinusReserveFactor).div(1e18);
return
utilizationRate(cash, borrows, reserves).mul(rateToPool).div(1e18);
}
/**
* @notice Internal function to update the parameters of the interest rate model
* @param baseRatePerYear The approximate target base APR, as a mantissa (scaled by 1e18)
* @param multiplierPerYear The rate of increase in interest rate wrt utilization (scaled by 1e18)
* @param jumpMultiplierPerYear The multiplierPerBlock after hitting a specified utilization point
* @param kink_ The utilization point at which the jump multiplier is applied
*/
function updateJumpRateModelInternal(
uint256 baseRatePerYear,
uint256 multiplierPerYear,
uint256 jumpMultiplierPerYear,
uint256 kink_
) internal {
baseRatePerBlock = baseRatePerYear.div(blocksPerYear);
multiplierPerBlock = (multiplierPerYear.mul(1e18)).div(
blocksPerYear.mul(kink_)
);
jumpMultiplierPerBlock = jumpMultiplierPerYear.div(blocksPerYear);
kink = kink_;
emit NewInterestParams(
baseRatePerBlock,
multiplierPerBlock,
jumpMultiplierPerBlock,
kink
);
}
}