Cooler
Inherits: Clone
A Cooler is a smart contract escrow that facilitates fixed-duration, peer-to-peer loans for a user-defined debt-collateral pair.
This contract uses Clones (https://github.com/wighawag/clones-with-immutable-args) to save gas on deployment.
State Variables
DECIMALS_INTEREST
uint256 private constant DECIMALS_INTEREST = 1e18;
requests
Arrays stores all the loan requests.
Request[] public requests;
loans
Arrays stores all the granted loans.
Loan[] public loans;
approvals
Facilitates transfer of lender ownership to new addresses
mapping(uint256 => address) public approvals;
Functions
owner
This address owns the collateral in escrow.
function owner() public pure returns (address _owner);
collateral
This token is borrowed against.
function collateral() public pure returns (ERC20 _collateral);
debt
This token is lent.
function debt() public pure returns (ERC20 _debt);
factory
This contract created the Cooler
function factory() public pure returns (CoolerFactory _factory);
requestLoan
Request a loan with given parameters. Collateral is taken at time of request.
function requestLoan(uint256 amount_, uint256 interest_, uint256 loanToCollateral_, uint256 duration_)
external
returns (uint256 reqID);
Parameters
| Name | Type | Description |
|---|---|---|
amount_ | uint256 | of debt tokens to borrow. |
interest_ | uint256 | to pay (annualized % of 'amount_'). Expressed in DECIMALS_INTEREST. |
loanToCollateral_ | uint256 | debt tokens per collateral token pledged. Expressed in 10**collateral().decimals(). |
duration_ | uint256 | of loan tenure in seconds. |
Returns
| Name | Type | Description |
|---|---|---|
reqID | uint256 | of the created request. Equivalent to the index of request in requests[]. |
rescindRequest
Cancel a loan request and get the collateral back.
function rescindRequest(uint256 reqID_) external;
Parameters
| Name | Type | Description |
|---|---|---|
reqID_ | uint256 | index of request in requests[]. |
repayLoan
Repay a loan to get the collateral back.
Despite a malicious lender could reenter with the callback, the
usage of msg.sender prevents any economical benefit to the
attacker, since they would be repaying the loan themselves.
function repayLoan(uint256 loanID_, uint256 repayment_) external returns (uint256);
Parameters
| Name | Type | Description |
|---|---|---|
loanID_ | uint256 | index of loan in loans[]. |
repayment_ | uint256 | debt tokens to be repaid. |
Returns
| Name | Type | Description |
|---|---|---|
<none> | uint256 | collateral given back to the borrower. |
delegateVoting
Delegate voting power on collateral.
function delegateVoting(address to_) external;
Parameters
| Name | Type | Description |
|---|---|---|
to_ | address | address to delegate. |
clearRequest
Fill a requested loan as a lender.
function clearRequest(uint256 reqID_, address recipient_, bool isCallback_) external returns (uint256 loanID);
Parameters
| Name | Type | Description |
|---|---|---|
reqID_ | uint256 | index of request in requests[]. |
recipient_ | address | address to repay the loan to. |
isCallback_ | bool | true if the lender implements the CoolerCallback abstract. False otherwise. |
Returns
| Name | Type | Description |
|---|---|---|
loanID | uint256 | of the granted loan. Equivalent to the index of loan in loans[]. |
extendLoanTerms
Allow lender to extend a loan for the borrower. Doesn't require borrower permission because it doesn't have a negative impact for them.
Since this function solely impacts the expiration day, the lender should ensure that extension interest payments are done beforehand.
function extendLoanTerms(uint256 loanID_, uint8 times_) external;
Parameters
| Name | Type | Description |
|---|---|---|
loanID_ | uint256 | index of loan in loans[]. |
times_ | uint8 | that the fixed-term loan duration is extended. |
claimDefaulted
Claim collateral upon loan default.
function claimDefaulted(uint256 loanID_) external returns (uint256, uint256, uint256, uint256);
Parameters
| Name | Type | Description |
|---|---|---|
loanID_ | uint256 | index of loan in loans[]. |
Returns
| Name | Type | Description |
|---|---|---|
<none> | uint256 | defaulted debt by the borrower, collateral kept by the lender, elapsed time since expiry. |
<none> | uint256 | |
<none> | uint256 | |
<none> | uint256 |
approveTransfer
Approve transfer of loan ownership rights to a new address.
function approveTransfer(address to_, uint256 loanID_) external;
Parameters
| Name | Type | Description |
|---|---|---|
to_ | address | address to be approved. |
loanID_ | uint256 | index of loan in loans[]. |
transferOwnership
Execute loan ownership transfer. Must be previously approved by the lender.
function transferOwnership(uint256 loanID_) external;
Parameters
| Name | Type | Description |
|---|---|---|
loanID_ | uint256 | index of loan in loans[]. |
setRepaymentAddress
Allow lender to set repayment recipient of a given loan.
function setRepaymentAddress(uint256 loanID_, address recipient_) external;
Parameters
| Name | Type | Description |
|---|---|---|
loanID_ | uint256 | of lender's loan. |
recipient_ | address | reciever of repayments |
collateralFor
Compute collateral needed for a desired loan amount at given loan to collateral ratio.
function collateralFor(uint256 principal_, uint256 loanToCollateral_) public view returns (uint256);
Parameters
| Name | Type | Description |
|---|---|---|
principal_ | uint256 | amount of debt tokens. |
loanToCollateral_ | uint256 | ratio for loan. Expressed in 10**collateral().decimals(). |
interestFor
Compute interest cost on amount for duration at given annualized rate.
function interestFor(uint256 principal_, uint256 rate_, uint256 duration_) public pure returns (uint256);
Parameters
| Name | Type | Description |
|---|---|---|
principal_ | uint256 | amount of debt tokens. |
rate_ | uint256 | of interest (annualized). |
duration_ | uint256 | of the loan in seconds. |
Returns
| Name | Type | Description |
|---|---|---|
<none> | uint256 | Interest in debt token terms. |
hasExpired
Check if given loan has expired.
function hasExpired(uint256 loanID_) external view returns (bool);
Parameters
| Name | Type | Description |
|---|---|---|
loanID_ | uint256 | index of loan in loans[]. |
Returns
| Name | Type | Description |
|---|---|---|
<none> | bool | Expiration status. |
isActive
Check if a given request is active.
function isActive(uint256 reqID_) external view returns (bool);
Parameters
| Name | Type | Description |
|---|---|---|
reqID_ | uint256 | index of request in requests[]. |
Returns
| Name | Type | Description |
|---|---|---|
<none> | bool | Active status. |
getRequest
Getter for Request data as a struct.
function getRequest(uint256 reqID_) external view returns (Request memory);
Parameters
| Name | Type | Description |
|---|---|---|
reqID_ | uint256 | index of request in requests[]. |
Returns
| Name | Type | Description |
|---|---|---|
<none> | Request | Request struct. |
getLoan
Getter for Loan data as a struct.
function getLoan(uint256 loanID_) external view returns (Loan memory);
Parameters
| Name | Type | Description |
|---|---|---|
loanID_ | uint256 | index of loan in loans[]. |
Returns
| Name | Type | Description |
|---|---|---|
<none> | Loan | Loan struct. |
Errors
OnlyApproved
error OnlyApproved();
Deactivated
error Deactivated();
Default
error Default();
NotExpired
error NotExpired();
NotCoolerCallback
error NotCoolerCallback();
Structs
Request
A loan begins with a borrow request.
struct Request {
uint256 amount;
uint256 interest;
uint256 loanToCollateral;
uint256 duration;
bool active;
address requester;
}
Loan
A request is converted to a loan when a lender clears it.
struct Loan {
Request request;
uint256 principal;
uint256 interestDue;
uint256 collateral;
uint256 expiry;
address lender;
address recipient;
bool callback;
}