TokenizedStrategy
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 = "3.0.4";
ENTERED
Value to set the entered
flag to during a call.
uint8 internal constant ENTERED = 2;
NOT_ENTERED
Value to set the entered
flag to at the end of the call.
uint8 internal constant NOT_ENTERED = 1;
MAX_FEE
Maximum in Basis Points the Performance Fee can be set to.
uint16 public constant MAX_FEE = 5_000;
MAX_BPS
Used for fee calculations.
uint256 internal constant MAX_BPS = 10_000;
MAX_BPS_EXTENDED
Used for profit unlocking rate calculations.
uint256 internal constant MAX_BPS_EXTENDED = 1_000_000_000_000;
SECONDS_PER_YEAR
Seconds per year for max profit unlocking time.
uint256 internal constant SECONDS_PER_YEAR = 31_556_952;
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 into the strategy, where receiver
corresponds to the receiver of the shares of a deposit call.
function maxDeposit(address receiver) external view returns (uint256);
Parameters
Name | Type | Description |
---|---|---|
receiver | address | The address receiving the shares. |
Returns
Name | Type | Description |
---|---|---|
<none> | uint256 | . The max that receiver can deposit in asset . |
maxMint
Total number of shares that can be minted to receiver
of a mint call.
function maxMint(address receiver) external view returns (uint256);
Parameters
Name | Type | Description |
---|---|---|
receiver | address | The address receiving the shares. |
Returns
Name | Type | Description |
---|---|---|
<none> | uint256 | _maxMint The max that receiver 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. |
maxWithdraw
Variable maxLoss
is ignored.
Accepts a maxLoss
variable in order to match the multi
strategy vaults ABI.
function maxWithdraw(address owner, uint256) external view returns (uint256);
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. |
maxRedeem
Variable maxLoss
is ignored.
Accepts a maxLoss
variable in order to match the multi
strategy vaults ABI.
function maxRedeem(address owner, uint256) external view returns (uint256);
_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 receiver) internal view returns (uint256);
_maxMint
Internal implementation of maxMint.
function _maxMint(StrategyData storage S, address receiver) 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 . |
setName
Updates the name for the strategy.
function setName(string calldata _name) external onlyManagement;
Parameters
Name | Type | Description |
---|---|---|
_name | string | The new name for the strategy. |
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 from
msg.senderto
to`.
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
andto
cannot be the zero address.to
cannot be the address of the strategy.from
must have a balance of at leastamount
.- the caller must have allowance for
from
's tokens of at leastamount
. Emits aTransfer
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 addressfrom
must have a balance of at leastamount
.*
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 leastamount
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
ands
must be a validsecp256k1
signature fromowner
over the EIP712-formatted function arguments.- the signature must use
owner
's current nonce (seenonces
). For more information on the signature format, see the https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP section].*
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
.
function DOMAIN_SEPARATOR() public view returns (bytes32);
Returns
Name | Type | Description |
---|---|---|
<none> | bytes32 | . The domain separator that will be used for any permit calls. |
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 owner
s 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;
string name;
uint256 totalSupply;
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;
}