YieldDepositFacility

Git Source

Inherits: BaseDepositFacility, IYieldDepositFacility, IPeriodicTask

NOTE: this contract is NOT ready for deployment, as it has some major design issues.

State Variables

_yieldFee

The yield fee

uint16 internal _yieldFee;

positionLastYieldClaimTimestamp

Mapping between a position id and the timestamp of the last yield claim

This is used to calculate the yield since the last claim. The initial value should be set at the time of minting.

mapping(uint256 positionId => uint48 lastYieldClaimTimestamp) public positionLastYieldClaimTimestamp;

vaultRateSnapshots

Mapping between vault address and timestamp to snapshot data

This is used to store periodic snapshots of conversion rates for each vault

mapping(IERC4626 => mapping(uint48 => uint256)) public vaultRateSnapshots;

vaultSnapshotTimestamps

Mapping between vault address and linked list of snapshot timestamps

This is used to efficiently find the most recent snapshot before a given timestamp

mapping(IERC4626 => TimestampLinkedList.List) public vaultSnapshotTimestamps;

Functions

constructor

constructor(address kernel_, address depositManager_) BaseDepositFacility(kernel_, depositManager_);

configureDependencies

Define module dependencies for this policy.

function configureDependencies() external override returns (Keycode[] memory dependencies);

Returns

Name	Type	Description
dependencies	Keycode[]	- Keycode array of module dependencies.

requestPermissions

Function called by kernel to set module function permissions.

function requestPermissions() external view override returns (Permissions[] memory permissions);

Returns

Name	Type	Description
permissions	Permissions[]	requests - Array of keycodes and function selectors for requested permissions.

VERSION

function VERSION() external pure returns (uint8 major, uint8 minor);

onlyYieldBearingAsset

modifier onlyYieldBearingAsset(IERC20 asset_, uint8 periodMonths_);

createPosition

Creates a position for a yield-bearing deposit

*This function reverts if:

• The contract is not enabled
• The asset token is not supported*

function createPosition(CreatePositionParams calldata params_)
    external
    nonReentrant
    onlyEnabled
    onlyYieldBearingAsset(params_.asset, params_.periodMonths)
    returns (uint256 positionId, uint256 receiptTokenId, uint256 actualAmount);

Parameters

Name	Type	Description
params_	CreatePositionParams	The parameters for the position creation

Returns

Name	Type	Description
positionId	uint256	The ID of the new position
receiptTokenId	uint256	The ID of the receipt token
actualAmount	uint256	The quantity of receipt tokens minted to the depositor

deposit

Deposits the given amount of the underlying asset in exchange for a receipt token. This function can be used to mint additional receipt tokens on a 1:1 basis, without creating a new position.

function deposit(IERC20 asset_, uint8 periodMonths_, uint256 amount_, bool wrapReceipt_)
    external
    nonReentrant
    onlyEnabled
    onlyYieldBearingAsset(asset_, periodMonths_)
    returns (uint256 receiptTokenId, uint256 actualAmount);

Parameters

Name	Type	Description
asset_	IERC20	The address of the asset
periodMonths_	uint8	The period of the deposit
amount_	uint256	The amount of asset to deposit
wrapReceipt_	bool	Whether the receipt token should be wrapped

Returns

Name	Type	Description
receiptTokenId	uint256	The ID of the receipt token
actualAmount	uint256	The quantity of receipt tokens minted to the depositor

_previewClaimYield

function _previewClaimYield(address account_, uint256 positionId_, address previousAsset_, uint8 previousPeriodMonths_)
    internal
    view
    returns (uint256 yieldMinusFee, uint256 yieldFee, uint48 newClaimTimestamp);

previewClaimYield

Preview the amount of yield that would be claimed for the given positions

Yield is calculated in the following manner:

- If before or at expiry: it will get the current vault rate

- If after expiry: it will get the last vault rate before or equal to the expiry timestamp

- The current value is calculated as: share quantity at previous claim vault rate*

- The yield is calculated as: current value - original deposit

**

Notes:

- For asset vaults that are not monotonically increasing in value, the yield received by different depositors may differ based on the time of claim.

- Claiming yield multiple times during a deposit period will likely result in a lower yield than claiming once at/after expiry.

- The actual amount of yield that can be claimed via claimYield() can differ by a few wei, due to rounding behaviour in ERC4626 vaults.

**

This function will revert if:

- The contract is not enabled

- The asset in the positions is not supported

- account_ is not the owner of all of the positions

- Any of the positions have a different asset and deposit period combination

- The position was not created by this contract

- The asset does not have a vault configured

- There is no snapshot for the asset at the last yield claim timestamp

function previewClaimYield(address account_, uint256[] memory positionIds_)
    external
    view
    onlyEnabled
    returns (uint256 yieldMinusFee, IERC20 asset);

Parameters

Name	Type	Description
account_	address	The address to preview the yield for
positionIds_	uint256[]	An array of position ids that will be claimed

Returns

Name	Type	Description
yieldMinusFee	uint256	yield The amount of yield that would be claimed
asset	IERC20	The address of the asset that will be received

claimYield

Claims the yield for the given positions

See also previewClaimYield for more details on the yield calculation.

function claimYield(uint256[] memory positionIds_) external onlyEnabled returns (uint256 yieldMinusFee);

Parameters

Name	Type	Description
positionIds_	uint256[]	An array of position ids that will be claimed

Returns

Name	Type	Description
yieldMinusFee	uint256	yield The amount of yield that was claimed

setYieldFee

Sets the percentage of yield that will be taken as a fee

*This function reverts if:

• The contract is not enabled
• The caller is not an admin
• The yield fee is greater than 100e2*

function setYieldFee(uint16 yieldFee_) external onlyEnabled onlyAdminRole;

Parameters

Name	Type	Description
yieldFee_	uint16	The percentage of yield that will be taken as a fee, in terms of 100e2

getYieldFee

Returns the percentage of yield that will be taken as a fee

function getYieldFee() external view returns (uint16);

Returns

Name	Type	Description
<none>	uint16	yieldFee The percentage of yield that will be taken as a fee, in terms of 100e2

_split

function _split(uint256 oldPositionId_, uint256 newPositionId_, uint256) internal virtual override;

_getConversionRate

Get the conversion rate between a vault and underlying asset

function _getConversionRate(IERC4626 vault_) internal view returns (uint256);

_findLastSnapshotBefore

Find the most recent snapshot timestamp at or before the target timestamp

function _findLastSnapshotBefore(IERC4626 vault_, uint48 target_) internal view returns (uint48);

Parameters

Name	Type	Description
vault_	IERC4626	The vault to search snapshots for
target_	uint48	The target timestamp

Returns

Name	Type	Description
<none>	uint48	The most recent snapshot timestamp <= target_, or 0 if none found

_takeSnapshot

Take a snapshot of the vault conversion rate for an asset

function _takeSnapshot(IERC20 asset_, uint48 timestamp_) internal returns (uint256);

Parameters

Name	Type	Description
asset_	IERC20	The asset to take a snapshot for
timestamp_	uint48	The timestamp for the snapshot

Returns

Name	Type	Description
<none>	uint256	The conversion rate that was stored, or 0 if no vault configured

execute

Stores periodic snapshots of the conversion rate for all supported vaults

This function is called by the Heart contract periodically

Uses the current block timestamp for the snapshot

No cleanup is performed as snapshots are needed for active deposits

function execute() external override onlyRole(HEART_ROLE);

supportsInterface

function supportsInterface(bytes4 interfaceId)
    public
    view
    virtual
    override(BaseDepositFacility, IPeriodicTask)
    returns (bool);