TokenizedStrategy.sol

Git Source

Author: yearn.finance

This TokenizedStrategy can be used by anyone wishing to easily build and deploy their own custom ERC4626 compliant single strategy Vault. The TokenizedStrategy contract is meant to be used as the proxy implementation contract that will handle all logic, storage and management for a custom strategy that inherits the BaseStrategy. Any function calls to the strategy that are not defined within that strategy will be forwarded through a delegateCall to this contract. A strategist only needs to override a few simple functions that are focused entirely on the strategy specific needs to easily and cheaply deploy their own permissionless 4626 compliant vault.

State Variables

API_VERSION

API version this TokenizedStrategy implements.

string internal constant API_VERSION = "3.0.2";

MAX_FEE

Maximum in Basis Points the Performance Fee can be set to.

uint16 public constant MAX_FEE = 5_000;

BASE_STRATEGY_STORAGE

Custom storage slot that will be used to store the StrategyData struct that holds each strategies specific storage variables. Any storage updates done by the TokenizedStrategy actually update the storage of the calling contract. This variable points to the specific location that will be used to store the struct that holds all that data. We use a custom string in order to get a random storage slot that will allow for strategists to use any amount of storage in their strategy without worrying about collisions.

bytes32 internal constant BASE_STRATEGY_STORAGE = bytes32(uint256(keccak256("yearn.base.strategy.storage")) - 1);

FACTORY

Address of the previously deployed Vault factory that the

address public immutable FACTORY;

Functions

onlyManagement

Require that the call is coming from the strategies management.

modifier onlyManagement();

onlyKeepers

Require that the call is coming from either the strategies management or the keeper.

modifier onlyKeepers();

onlyEmergencyAuthorized

Require that the call is coming from either the strategies management or the emergencyAdmin.

modifier onlyEmergencyAuthorized();

nonReentrant

Prevents a contract from calling itself, directly or indirectly. Placed over all state changing functions for increased safety.

modifier nonReentrant();

requireManagement

Require a caller is management.

Is left public so that it can be used by the Strategy. When the Strategy calls this the msg.sender would be the address of the strategy so we need to specify the sender.

function requireManagement(address _sender) public view;

Parameters

Name	Type	Description
_sender	address	The original msg.sender.

requireKeeperOrManagement

Require a caller is the keeper or management.

Is left public so that it can be used by the Strategy. When the Strategy calls this the msg.sender would be the address of the strategy so we need to specify the sender.

function requireKeeperOrManagement(address _sender) public view;

Parameters

Name	Type	Description
_sender	address	The original msg.sender.

requireEmergencyAuthorized

Require a caller is the management or emergencyAdmin.

Is left public so that it can be used by the Strategy. When the Strategy calls this the msg.sender would be the address of the strategy so we need to specify the sender.

function requireEmergencyAuthorized(address _sender) public view;

Parameters

Name	Type	Description
_sender	address	The original msg.sender.

_strategyStorage

will return the actual storage slot where the strategy specific StrategyData struct is stored for both read and write operations. This loads just the slot location, not the full struct so it can be used in a gas efficient manner.

function _strategyStorage() internal pure returns (StrategyData storage S);

initialize

Used to initialize storage for a newly deployed strategy.

This should be called atomically whenever a new strategy is deployed and can only be called once for each strategy. This will set all the default storage that must be set for a strategy to function. Any changes can be made post deployment through external calls from management. The function will also emit an event that off chain indexers can look for to track any new deployments using this TokenizedStrategy.

function initialize(
    address _asset,
    string memory _name,
    address _management,
    address _performanceFeeRecipient,
    address _keeper
) external;

Parameters

Name	Type	Description
_asset	address	Address of the underlying asset.
_name	string	Name the strategy will use.
_management	address	Address to set as the strategies management.
_performanceFeeRecipient	address	Address to receive performance fees.
_keeper	address	Address to set as strategies keeper.

deposit

Mints shares of strategy shares to receiver by depositing exactly assets of underlying tokens.

function deposit(uint256 assets, address receiver) external nonReentrant returns (uint256 shares);

Parameters

Name	Type	Description
assets	uint256	The amount of underlying to deposit in.
receiver	address	The address to receive the shares.

Returns

Name	Type	Description
shares	uint256	The actual amount of shares issued.

mint

Mints exactly shares of strategy shares to receiver by depositing assets of underlying tokens.

function mint(uint256 shares, address receiver) external nonReentrant returns (uint256 assets);

Parameters

Name	Type	Description
shares	uint256	The amount of strategy shares mint.
receiver	address	The address to receive the shares.

Returns

Name	Type	Description
assets	uint256	The actual amount of asset deposited.

withdraw

Withdraws exactly assets from owners shares and sends the underlying tokens to receiver.

This will default to not allowing any loss to be taken.

function withdraw(uint256 assets, address receiver, address owner) external returns (uint256 shares);

Parameters

Name	Type	Description
assets	uint256	The amount of underlying to withdraw.
receiver	address	The address to receive assets.
owner	address	The address whose shares are burnt.

Returns

Name	Type	Description
shares	uint256	The actual amount of shares burnt.

withdraw

Withdraws assets from owners shares and sends the underlying tokens to receiver.

This includes an added parameter to allow for losses.

function withdraw(uint256 assets, address receiver, address owner, uint256 maxLoss)
    public
    nonReentrant
    returns (uint256 shares);

Parameters

Name	Type	Description
assets	uint256	The amount of underlying to withdraw.
receiver	address	The address to receive assets.
owner	address	The address whose shares are burnt.
maxLoss	uint256	The amount of acceptable loss in Basis points.

Returns

Name	Type	Description
shares	uint256	The actual amount of shares burnt.

redeem

Redeems exactly shares from owner and sends assets of underlying tokens to receiver.

This will default to allowing any loss passed to be realized.

function redeem(uint256 shares, address receiver, address owner) external returns (uint256);

Parameters

Name	Type	Description
shares	uint256	The amount of shares burnt.
receiver	address	The address to receive assets.
owner	address	The address whose shares are burnt.

Returns

Name	Type	Description
<none>	uint256	assets The actual amount of underlying withdrawn.

redeem

Redeems exactly shares from owner and sends assets of underlying tokens to receiver.

This includes an added parameter to allow for losses.

function redeem(uint256 shares, address receiver, address owner, uint256 maxLoss)
    public
    nonReentrant
    returns (uint256);

Parameters

Name	Type	Description
shares	uint256	The amount of shares burnt.
receiver	address	The address to receive assets.
owner	address	The address whose shares are burnt.
maxLoss	uint256	The amount of acceptable loss in Basis points.

Returns

Name	Type	Description
<none>	uint256	. The actual amount of underlying withdrawn.

totalAssets

Get the total amount of assets this strategy holds as of the last report. We manually track totalAssets to avoid any PPS manipulation.

function totalAssets() external view returns (uint256);

Returns

Name	Type	Description
<none>	uint256	. Total assets the strategy holds.

totalSupply

Get the current supply of the strategies shares. Locked shares issued to the strategy from profits are not counted towards the full supply until they are unlocked. As more shares slowly unlock the totalSupply will decrease causing the PPS of the strategy to increase.

function totalSupply() external view returns (uint256);

Returns

Name	Type	Description
<none>	uint256	. Total amount of shares outstanding.

convertToShares

The amount of shares that the strategy would exchange for the amount of assets provided, in an ideal scenario where all the conditions are met.

function convertToShares(uint256 assets) external view returns (uint256);

Parameters

Name	Type	Description
assets	uint256	The amount of underlying.

Returns

Name	Type	Description
<none>	uint256	. Expected shares that assets represents.

convertToAssets

The amount of assets that the strategy would exchange for the amount of shares provided, in an ideal scenario where all the conditions are met.

function convertToAssets(uint256 shares) external view returns (uint256);

Parameters

Name	Type	Description
shares	uint256	The amount of the strategies shares.

Returns

Name	Type	Description
<none>	uint256	. Expected amount of asset the shares represents.

previewDeposit

Allows an on-chain or off-chain user to simulate the effects of their deposit at the current block, given current on-chain conditions.

This will round down.

function previewDeposit(uint256 assets) external view returns (uint256);

Parameters

Name	Type	Description
assets	uint256	The amount of asset to deposits.

Returns

Name	Type	Description
<none>	uint256	. Expected shares that would be issued.

previewMint

Allows an on-chain or off-chain user to simulate the effects of their mint at the current block, given current on-chain conditions.

This is used instead of convertToAssets so that it can round up for safer mints.

function previewMint(uint256 shares) external view returns (uint256);

Parameters

Name	Type	Description
shares	uint256	The amount of shares to mint.

Returns

Name	Type	Description
<none>	uint256	. The needed amount of asset for the mint.

previewWithdraw

Allows an on-chain or off-chain user to simulate the effects of their withdrawal at the current block, given current on-chain conditions.

This is used instead of convertToShares so that it can round up for safer withdraws.

function previewWithdraw(uint256 assets) external view returns (uint256);

Parameters

Name	Type	Description
assets	uint256	The amount of asset that would be withdrawn.

Returns

Name	Type	Description
<none>	uint256	. The amount of shares that would be burnt.

previewRedeem

Allows an on-chain or off-chain user to simulate the effects of their redemption at the current block, given current on-chain conditions.

This will round down.

function previewRedeem(uint256 shares) external view returns (uint256);

Parameters

Name	Type	Description
shares	uint256	The amount of shares that would be redeemed.

Returns

Name	Type	Description
<none>	uint256	. The amount of asset that would be returned.

maxDeposit

Total number of underlying assets that can be deposited by _owner into the strategy, where owner corresponds to the receiver of a deposit call.

function maxDeposit(address owner) external view returns (uint256);

Parameters

Name	Type	Description
owner	address	The address depositing.

Returns

Name	Type	Description
<none>	uint256	. The max that owner can deposit in asset.

maxMint

Total number of shares that can be minted by owner into the strategy, where _owner corresponds to the receiver of a mint call.

function maxMint(address owner) external view returns (uint256);

Parameters

Name	Type	Description
owner	address	The address minting.

Returns

Name	Type	Description
<none>	uint256	_maxMint The max that owner can mint in shares.

maxWithdraw

Total number of underlying assets that can be withdrawn from the strategy by owner, where owner corresponds to the msg.sender of a redeem call.

function maxWithdraw(address owner) external view returns (uint256);

Parameters

Name	Type	Description
owner	address	The owner of the shares.

Returns

Name	Type	Description
<none>	uint256	_maxWithdraw Max amount of asset that can be withdrawn.

maxRedeem

Total number of strategy shares that can be redeemed from the strategy by owner, where owner corresponds to the msg.sender of a redeem call.

function maxRedeem(address owner) external view returns (uint256);

Parameters

Name	Type	Description
owner	address	The owner of the shares.

Returns

Name	Type	Description
<none>	uint256	_maxRedeem Max amount of shares that can be redeemed.

_totalAssets

Internal implementation of totalAssets.

function _totalAssets(StrategyData storage S) internal view returns (uint256);

_totalSupply

Internal implementation of totalSupply.

function _totalSupply(StrategyData storage S) internal view returns (uint256);

_convertToShares

Internal implementation of convertToShares.

function _convertToShares(StrategyData storage S, uint256 assets, Math.Rounding _rounding)
    internal
    view
    returns (uint256);

_convertToAssets

Internal implementation of convertToAssets.

function _convertToAssets(StrategyData storage S, uint256 shares, Math.Rounding _rounding)
    internal
    view
    returns (uint256);

_maxDeposit

Internal implementation of maxDeposit.

function _maxDeposit(StrategyData storage S, address owner) internal view returns (uint256);

_maxMint

Internal implementation of maxMint.

function _maxMint(StrategyData storage S, address owner) internal view returns (uint256 maxMint_);

_maxWithdraw

Internal implementation of maxWithdraw.

function _maxWithdraw(StrategyData storage S, address owner) internal view returns (uint256 maxWithdraw_);

_maxRedeem

Internal implementation of maxRedeem.

function _maxRedeem(StrategyData storage S, address owner) internal view returns (uint256 maxRedeem_);

_deposit

Function to be called during deposit and mint. This function handles all logic including transfers, minting and accounting. We do all external calls before updating any internal values to prevent view reentrancy issues from the token transfers or the _deployFunds() calls.

function _deposit(StrategyData storage S, address receiver, uint256 assets, uint256 shares) internal;

_withdraw

To be called during redeem and withdraw. This will handle all logic, transfers and accounting in order to service the withdraw request. If we are not able to withdraw the full amount needed, it will be counted as a loss and passed on to the user.

function _withdraw(
    StrategyData storage S,
    address receiver,
    address owner,
    uint256 assets,
    uint256 shares,
    uint256 maxLoss
) internal returns (uint256);

report

Function for keepers to call to harvest and record all profits accrued.

This will account for any gains/losses since the last report and charge fees accordingly. Any profit over the fees charged will be immediately locked so there is no change in PricePerShare. Then slowly unlocked over the maxProfitUnlockTime each second based on the calculated profitUnlockingRate. In case of a loss it will first attempt to offset the loss with any remaining locked shares from the last report in order to reduce any negative impact to PPS. Will then recalculate the new time to unlock profits over and the rate based on a weighted average of any remaining time from the last report and the new amount of shares to be locked.

function report() external nonReentrant onlyKeepers returns (uint256 profit, uint256 loss);

Returns

Name	Type	Description
profit	uint256	The notional amount of gain if any since the last report in terms of asset.
loss	uint256	The notional amount of loss if any since the last report in terms of asset.

unlockedShares

Get how many shares have been unlocked since last report.

function unlockedShares() external view returns (uint256);

Returns

Name	Type	Description
<none>	uint256	. The amount of shares that have unlocked.

_unlockedShares

To determine how many of the shares that were locked during the last report have since unlocked. If the fullProfitUnlockDate has passed the full strategy's balance will count as unlocked.

function _unlockedShares(StrategyData storage S) internal view returns (uint256 unlocked);

Returns

Name	Type	Description
unlocked	uint256	The amount of shares that have unlocked.

tend

For a 'keeper' to 'tend' the strategy if a custom tendTrigger() is implemented.

Both 'tendTrigger' and '_tend' will need to be overridden for this to be used. This will callback the internal '_tend' call in the BaseStrategy with the total current amount available to the strategy to deploy. This is a permissioned function so if desired it could be used for illiquid or manipulatable strategies to compound rewards, perform maintenance or deposit/withdraw funds. This will not cause any change in PPS. Total assets will be the same before and after. A report() call will be needed to record any profits or losses.

function tend() external nonReentrant onlyKeepers;

shutdownStrategy

Used to shutdown the strategy preventing any further deposits.

Can only be called by the current management or emergencyAdmin. This will stop any new deposit or mint calls but will not prevent withdraw or redeem. It will also still allow for tend and report so that management can report any last losses in an emergency as well as provide any maintenance to allow for full withdraw. This is a one way switch and can never be set back once shutdown.

function shutdownStrategy() external onlyEmergencyAuthorized;

emergencyWithdraw

To manually withdraw funds from the yield source after a strategy has been shutdown.

This can only be called post shutdownStrategy. This will never cause a change in PPS. Total assets will be the same before and after. A strategist will need to override the _emergencyWithdraw function in their strategy for this to work.

function emergencyWithdraw(uint256 amount) external nonReentrant onlyEmergencyAuthorized;

Parameters

Name	Type	Description
amount	uint256	The amount of asset to attempt to free.

asset

Get the underlying asset for the strategy.

function asset() external view returns (address);

Returns

Name	Type	Description
<none>	address	. The underlying asset.

apiVersion

Get the API version for this TokenizedStrategy.

function apiVersion() external pure returns (string memory);

Returns

Name	Type	Description
<none>	string	. The API version for this TokenizedStrategy

management

Get the current address that controls the strategy.

function management() external view returns (address);

Returns

Name	Type	Description
<none>	address	. Address of management

pendingManagement

Get the current pending management address if any.

function pendingManagement() external view returns (address);

Returns

Name	Type	Description
<none>	address	. Address of pendingManagement

keeper

Get the current address that can call tend and report.

function keeper() external view returns (address);

Returns

Name	Type	Description
<none>	address	. Address of the keeper

emergencyAdmin

Get the current address that can shutdown and emergency withdraw.

function emergencyAdmin() external view returns (address);

Returns

Name	Type	Description
<none>	address	. Address of the emergencyAdmin

performanceFee

Get the current performance fee charged on profits. denominated in Basis Points where 10_000 == 100%

function performanceFee() external view returns (uint16);

Returns

Name	Type	Description
<none>	uint16	. Current performance fee.

performanceFeeRecipient

Get the current address that receives the performance fees.

function performanceFeeRecipient() external view returns (address);

Returns

Name	Type	Description
<none>	address	. Address of performanceFeeRecipient

fullProfitUnlockDate

Gets the timestamp at which all profits will be unlocked.

function fullProfitUnlockDate() external view returns (uint256);

Returns

Name	Type	Description
<none>	uint256	. The full profit unlocking timestamp

profitUnlockingRate

The per second rate at which profits are unlocking.

This is denominated in EXTENDED_BPS decimals.

function profitUnlockingRate() external view returns (uint256);

Returns

Name	Type	Description
<none>	uint256	. The current profit unlocking rate.

profitMaxUnlockTime

Gets the current time profits are set to unlock over.

function profitMaxUnlockTime() external view returns (uint256);

Returns

Name	Type	Description
<none>	uint256	. The current profit max unlock time.

lastReport

The timestamp of the last time protocol fees were charged.

function lastReport() external view returns (uint256);

Returns

Name	Type	Description
<none>	uint256	. The last report.

pricePerShare

Get the price per share.

This value offers limited precision. Integrations that require exact precision should use convertToAssets or convertToShares instead.

function pricePerShare() external view returns (uint256);

Returns

Name	Type	Description
<none>	uint256	. The price per share.

isShutdown

To check if the strategy has been shutdown.

function isShutdown() external view returns (bool);

Returns

Name	Type	Description
<none>	bool	. Whether or not the strategy is shutdown.

setPendingManagement

Step one of two to set a new address to be in charge of the strategy.

Can only be called by the current management. The address is set to pending management and will then have to call acceptManagement in order for the 'management' to officially change. Cannot set management to address(0).

function setPendingManagement(address _management) external onlyManagement;

Parameters

Name	Type	Description
_management	address	New address to set pendingManagement to.

acceptManagement

Step two of two to set a new 'management' of the strategy.

Can only be called by the current pendingManagement.

function acceptManagement() external;

setKeeper

Sets a new address to be in charge of tend and reports.

Can only be called by the current management.

function setKeeper(address _keeper) external onlyManagement;

Parameters

Name	Type	Description
_keeper	address	New address to set keeper to.

setEmergencyAdmin

Sets a new address to be able to shutdown the strategy.

Can only be called by the current management.

function setEmergencyAdmin(address _emergencyAdmin) external onlyManagement;

Parameters

Name	Type	Description
_emergencyAdmin	address	New address to set emergencyAdmin to.

setPerformanceFee

Sets the performance fee to be charged on reported gains.

Can only be called by the current management. Denominated in Basis Points. So 100% == 10_000. Cannot set greater than to MAX_FEE.

function setPerformanceFee(uint16 _performanceFee) external onlyManagement;

Parameters

Name	Type	Description
_performanceFee	uint16	New performance fee.

setPerformanceFeeRecipient

Sets a new address to receive performance fees.

Can only be called by the current management. Cannot set to address(0).

function setPerformanceFeeRecipient(address _performanceFeeRecipient) external onlyManagement;

Parameters

Name	Type	Description
_performanceFeeRecipient	address	New address to set management to.

setProfitMaxUnlockTime

Sets the time for profits to be unlocked over.

Can only be called by the current management. Denominated in seconds and cannot be greater than 1 year. NOTE: Setting to 0 will cause all currently locked profit to be unlocked instantly and should be done with care. profitMaxUnlockTime is stored as a uint32 for packing but can be passed in as uint256 for simplicity.

function setProfitMaxUnlockTime(uint256 _profitMaxUnlockTime) external onlyManagement;

Parameters

Name	Type	Description
_profitMaxUnlockTime	uint256	New profitMaxUnlockTime.

name

Returns the name of the token.

function name() external view returns (string memory);

Returns

Name	Type	Description
<none>	string	. The name the strategy is using for its token.

symbol

Returns the symbol of the strategies token.

Will be 'ys + asset symbol'.

function symbol() external view returns (string memory);

Returns

Name	Type	Description
<none>	string	. The symbol the strategy is using for its tokens.

decimals

Returns the number of decimals used to get its user representation.

function decimals() external view returns (uint8);

Returns

Name	Type	Description
<none>	uint8	. The decimals used for the strategy and asset.

balanceOf

Returns the current balance for a given '_account'.

If the '_account` is the strategy then this will subtract the amount of shares that have been unlocked since the last profit first.

function balanceOf(address account) external view returns (uint256);

Parameters

Name	Type	Description
account	address	the address to return the balance for.

Returns

Name	Type	Description
<none>	uint256	. The current balance in y shares of the '_account'.

_balanceOf

Internal implementation of balanceOf.

function _balanceOf(StrategyData storage S, address account) internal view returns (uint256);

transfer

Transfer '_amountof shares frommsg.sendertoto`.

Requirements:

• to cannot be the zero address.
• to cannot be the address of the strategy.
• the caller must have a balance of at least _amount.*

function transfer(address to, uint256 amount) external returns (bool);

Parameters

Name	Type	Description
to	address	The address shares will be transferred to.
amount	uint256	The amount of shares to be transferred from sender.

Returns

Name	Type	Description
<none>	bool	. a boolean value indicating whether the operation succeeded.

allowance

Returns the remaining number of tokens that spender will be allowed to spend on behalf of owner through transferFrom. This is zero by default. This value changes when approve or transferFrom are called.

function allowance(address owner, address spender) external view returns (uint256);

Parameters

Name	Type	Description
owner	address	The address who owns the shares.
spender	address	The address who would be moving the owners shares.

Returns

Name	Type	Description
<none>	uint256	. The remaining amount of shares of owner that could be moved by spender.

_allowance

Internal implementation of allowance.

function _allowance(StrategyData storage S, address owner, address spender) internal view returns (uint256);

approve

Sets amount as the allowance of spender over the caller's tokens.

NOTE: If amount is the maximum uint256, the allowance is not updated on transferFrom. This is semantically equivalent to an infinite approval. Requirements:

• spender cannot be the zero address. IMPORTANT: Beware that changing an allowance with this method brings the risk that someone may use both the old and the new allowance by unfortunate transaction ordering. One possible solution to mitigate this race condition is to first reduce the spender's allowance to 0 and set the desired value afterwards: https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729 Emits an Approval event.*

function approve(address spender, uint256 amount) external returns (bool);

Parameters

Name	Type	Description
spender	address	the address to allow the shares to be moved by.
amount	uint256	the amount of shares to allow spender to move.

Returns

Name	Type	Description
<none>	bool	. a boolean value indicating whether the operation succeeded.

transferFrom

amount tokens from from to to using the allowance mechanism. amount is then deducted from the caller's allowance.

Emits an Approval event indicating the updated allowance. This is not required by the EIP. NOTE: Does not update the allowance if the current allowance is the maximum uint256. Requirements:

• from and to cannot be the zero address.
• to cannot be the address of the strategy.
• from must have a balance of at least amount.
• the caller must have allowance for from's tokens of at least amount. Emits a Transfer event.*

function transferFrom(address from, address to, uint256 amount) external returns (bool);

Parameters

Name	Type	Description
from	address	the address to be moving shares from.
to	address	the address to be moving shares to.
amount	uint256	the quantity of shares to move.

Returns

Name	Type	Description
<none>	bool	. a boolean value indicating whether the operation succeeded.

_transfer

*Moves amount of tokens from from to to. This internal function is equivalent to transfer, and can be used to e.g. implement automatic token fees, slashing mechanisms, etc. Emits a Transfer event. Requirements:

• from cannot be the zero address.
• to cannot be the zero address.
• to cannot be the strategies address
• from must have a balance of at least amount.*

function _transfer(StrategyData storage S, address from, address to, uint256 amount) internal;

_mint

*Creates amount tokens and assigns them to account, increasing the total supply. Emits a Transfer event with from set to the zero address. Requirements:

• account cannot be the zero address.*

function _mint(StrategyData storage S, address account, uint256 amount) internal;

_burn

*Destroys amount tokens from account, reducing the total supply. Emits a Transfer event with to set to the zero address. Requirements:

• account cannot be the zero address.
• account must have at least amount tokens.*

function _burn(StrategyData storage S, address account, uint256 amount) internal;

_approve

*Sets amount as the allowance of spender over the owner s tokens. This internal function is equivalent to approve, and can be used to e.g. set automatic allowances for certain subsystems, etc. Emits an Approval event. Requirements:

• owner cannot be the zero address.
• spender cannot be the zero address.*

function _approve(StrategyData storage S, address owner, address spender, uint256 amount) internal;

_spendAllowance

Updates owner s allowance for spender based on spent amount. Does not update the allowance amount in case of infinite allowance. Revert if not enough allowance is available. Might emit an Approval event.

function _spendAllowance(StrategyData storage S, address owner, address spender, uint256 amount) internal;

nonces

Returns the current nonce for owner. This value must be included whenever a signature is generated for permit.

Every successful call to permit increases owner's nonce by one. This prevents a signature from being used multiple times.

function nonces(address _owner) external view returns (uint256);

Parameters

Name	Type	Description
_owner	address	the address of the account to return the nonce for.

Returns

Name	Type	Description
<none>	uint256	. the current nonce for the account.

permit

Sets value as the allowance of spender over owner's tokens, given owner's signed approval.

*IMPORTANT: The same issues IERC20-approve has related to transaction ordering also apply here. Emits an Approval event. Requirements:

• spender cannot be the zero address.
• deadline must be a timestamp in the future.
• v, r and s must be a valid secp256k1 signature from owner over the EIP712-formatted function arguments.
• the signature must use owner's current nonce (see nonces). For more information on the signature format, see https://eips.ethereum.org/EIPS/eip-2612#specification.*

function permit(address owner, address spender, uint256 value, uint256 deadline, uint8 v, bytes32 r, bytes32 s)
    external;

DOMAIN_SEPARATOR

Returns the domain separator used in the encoding of the signature for permit, as defined by EIP712.

This checks that the current chain id is the same as when the contract was deployed to prevent replay attacks. If false it will calculate a new domain separator based on the new chain id.

function DOMAIN_SEPARATOR() public view returns (bytes32);

Returns

Name	Type	Description
<none>	bytes32	. The domain separator that will be used for any permit calls.

_computeDomainSeparator

Calculates and returns the domain separator to be used in any permit functions for the strategies permit calls. This will be used at the initialization of each new strategies storage. It would then be used in the future in the case of any forks in which the current chain id is not the same as the original.

function _computeDomainSeparator(StrategyData storage S) internal view returns (bytes32);

constructor

On contract creation we set asset for this contract to address(1). This prevents it from ever being initialized in the future.

constructor(address _factory);

Parameters

Name	Type	Description
_factory	address	Address of the factory of the same version for protocol fees.

Events

StrategyShutdown

Emitted when a strategy is shutdown.

event StrategyShutdown();

NewTokenizedStrategy

Emitted on the initialization of any new strategy that uses asset with this specific apiVersion.

event NewTokenizedStrategy(address indexed strategy, address indexed asset, string apiVersion);

Reported

Emitted when the strategy reports profit or loss and performanceFees and protocolFees are paid out.

event Reported(uint256 profit, uint256 loss, uint256 protocolFees, uint256 performanceFees);

UpdatePerformanceFeeRecipient

Emitted when the 'performanceFeeRecipient' address is updated to 'newPerformanceFeeRecipient'.

event UpdatePerformanceFeeRecipient(address indexed newPerformanceFeeRecipient);

UpdateKeeper

Emitted when the 'keeper' address is updated to 'newKeeper'.

event UpdateKeeper(address indexed newKeeper);

UpdatePerformanceFee

Emitted when the 'performanceFee' is updated to 'newPerformanceFee'.

event UpdatePerformanceFee(uint16 newPerformanceFee);

UpdateManagement

Emitted when the 'management' address is updated to 'newManagement'.

event UpdateManagement(address indexed newManagement);

UpdateEmergencyAdmin

Emitted when the 'emergencyAdmin' address is updated to 'newEmergencyAdmin'.

event UpdateEmergencyAdmin(address indexed newEmergencyAdmin);

UpdateProfitMaxUnlockTime

Emitted when the 'profitMaxUnlockTime' is updated to 'newProfitMaxUnlockTime'.

event UpdateProfitMaxUnlockTime(uint256 newProfitMaxUnlockTime);

UpdatePendingManagement

Emitted when the 'pendingManagement' address is updated to 'newPendingManagement'.

event UpdatePendingManagement(address indexed newPendingManagement);

Approval

Emitted when the allowance of a spender for an owner is set by a call to approve. value is the new allowance.

event Approval(address indexed owner, address indexed spender, uint256 value);

Transfer

Emitted when value tokens are moved from one account (from) to another (to). Note that value may be zero.

event Transfer(address indexed from, address indexed to, uint256 value);

Deposit

Emitted when the caller has exchanged assets for shares, and transferred those shares to owner.

event Deposit(address indexed caller, address indexed owner, uint256 assets, uint256 shares);

Withdraw

Emitted when the caller has exchanged owners shares for assets, and transferred those assets to receiver.

event Withdraw(address indexed caller, address indexed receiver, address indexed owner, uint256 assets, uint256 shares);

Structs

StrategyData

The struct that will hold all the storage data for each strategy that uses this implementation. This replaces all state variables for a traditional contract. This full struct will be initialized on the creation of the strategy and continually updated and read from for the life of the contract. We combine all the variables into one struct to limit the amount of times the custom storage slots need to be loaded during complex functions. Loading the corresponding storage slot for the struct does not load any of the contents of the struct into memory. So the size will not increase memory related gas usage.

struct StrategyData {
    ERC20 asset;
    uint8 decimals;
    uint88 INITIAL_CHAIN_ID;
    string name;
    uint256 totalSupply;
    bytes32 INITIAL_DOMAIN_SEPARATOR;
    mapping(address => uint256) nonces;
    mapping(address => uint256) balances;
    mapping(address => mapping(address => uint256)) allowances;
    uint256 totalAssets;
    uint256 profitUnlockingRate;
    uint96 fullProfitUnlockDate;
    address keeper;
    uint32 profitMaxUnlockTime;
    uint16 performanceFee;
    address performanceFeeRecipient;
    uint96 lastReport;
    address management;
    address pendingManagement;
    address emergencyAdmin;
    uint8 entered;
    bool shutdown;
}