1// SPDX-License-Identifier: MIT
  2pragma solidity >=0.6.2;
  3
  4import "./IERC20.sol";
  5
  6/// @dev Interface of the ERC4626 "Tokenized Vault Standard", as defined in
  7/// https://eips.ethereum.org/EIPS/eip-4626
  8interface IERC4626 is IERC20 {
  9    event Deposit(address indexed sender, address indexed owner, uint256 assets, uint256 shares);
 10
 11    event Withdraw(
 12        address indexed sender, address indexed receiver, address indexed owner, uint256 assets, uint256 shares
 13    );
 14
 15    /// @notice Returns the address of the underlying token used for the Vault for accounting, depositing, and withdrawing.
 16    /// @dev
 17    /// - MUST be an ERC-20 token contract.
 18    /// - MUST NOT revert.
 19    function asset() external view returns (address assetTokenAddress);
 20
 21    /// @notice Returns the total amount of the underlying asset that is “managed” by Vault.
 22    /// @dev
 23    /// - SHOULD include any compounding that occurs from yield.
 24    /// - MUST be inclusive of any fees that are charged against assets in the Vault.
 25    /// - MUST NOT revert.
 26    function totalAssets() external view returns (uint256 totalManagedAssets);
 27
 28    /// @notice Returns the amount of shares that the Vault would exchange for the amount of assets provided, in an ideal
 29    /// scenario where all the conditions are met.
 30    /// @dev
 31    /// - MUST NOT be inclusive of any fees that are charged against assets in the Vault.
 32    /// - MUST NOT show any variations depending on the caller.
 33    /// - MUST NOT reflect slippage or other on-chain conditions, when performing the actual exchange.
 34    /// - MUST NOT revert.
 35    ///
 36    /// NOTE: This calculation MAY NOT reflect the “per-user” price-per-share, and instead should reflect the
 37    /// “average-user’s” price-per-share, meaning what the average user should expect to see when exchanging to and
 38    /// from.
 39    function convertToShares(uint256 assets) external view returns (uint256 shares);
 40
 41    /// @notice Returns the amount of assets that the Vault would exchange for the amount of shares provided, in an ideal
 42    /// scenario where all the conditions are met.
 43    /// @dev
 44    /// - MUST NOT be inclusive of any fees that are charged against assets in the Vault.
 45    /// - MUST NOT show any variations depending on the caller.
 46    /// - MUST NOT reflect slippage or other on-chain conditions, when performing the actual exchange.
 47    /// - MUST NOT revert.
 48    ///
 49    /// NOTE: This calculation MAY NOT reflect the “per-user” price-per-share, and instead should reflect the
 50    /// “average-user’s” price-per-share, meaning what the average user should expect to see when exchanging to and
 51    /// from.
 52    function convertToAssets(uint256 shares) external view returns (uint256 assets);
 53
 54    /// @notice Returns the maximum amount of the underlying asset that can be deposited into the Vault for the receiver,
 55    /// through a deposit call.
 56    /// @dev
 57    /// - MUST return a limited value if receiver is subject to some deposit limit.
 58    /// - MUST return 2 ** 256 - 1 if there is no limit on the maximum amount of assets that may be deposited.
 59    /// - MUST NOT revert.
 60    function maxDeposit(address receiver) external view returns (uint256 maxAssets);
 61
 62    /// @notice Allows an on-chain or off-chain user to simulate the effects of their deposit at the current block, given
 63    /// current on-chain conditions.
 64    /// @dev
 65    /// - MUST return as close to and no more than the exact amount of Vault shares that would be minted in a deposit
 66    ///   call in the same transaction. I.e. deposit should return the same or more shares as previewDeposit if called
 67    ///   in the same transaction.
 68    /// - MUST NOT account for deposit limits like those returned from maxDeposit and should always act as though the
 69    ///   deposit would be accepted, regardless if the user has enough tokens approved, etc.
 70    /// - MUST be inclusive of deposit fees. Integrators should be aware of the existence of deposit fees.
 71    /// - MUST NOT revert.
 72    ///
 73    /// NOTE: any unfavorable discrepancy between convertToShares and previewDeposit SHOULD be considered slippage in
 74    /// share price or some other type of condition, meaning the depositor will lose assets by depositing.
 75    function previewDeposit(uint256 assets) external view returns (uint256 shares);
 76
 77    /// @notice Mints shares Vault shares to receiver by depositing exactly amount of underlying tokens.
 78    /// @dev
 79    /// - MUST emit the Deposit event.
 80    /// - MAY support an additional flow in which the underlying tokens are owned by the Vault contract before the
 81    ///   deposit execution, and are accounted for during deposit.
 82    /// - MUST revert if all of assets cannot be deposited (due to deposit limit being reached, slippage, the user not
 83    ///   approving enough underlying tokens to the Vault contract, etc).
 84    ///
 85    /// NOTE: most implementations will require pre-approval of the Vault with the Vault’s underlying asset token.
 86    function deposit(uint256 assets, address receiver) external returns (uint256 shares);
 87
 88    /// @notice Returns the maximum amount of the Vault shares that can be minted for the receiver, through a mint call.
 89    /// @dev
 90    /// - MUST return a limited value if receiver is subject to some mint limit.
 91    /// - MUST return 2 ** 256 - 1 if there is no limit on the maximum amount of shares that may be minted.
 92    /// - MUST NOT revert.
 93    function maxMint(address receiver) external view returns (uint256 maxShares);
 94
 95    /// @notice Allows an on-chain or off-chain user to simulate the effects of their mint at the current block, given
 96    /// current on-chain conditions.
 97    /// @dev
 98    /// - MUST return as close to and no fewer than the exact amount of assets that would be deposited in a mint call
 99    ///   in the same transaction. I.e. mint should return the same or fewer assets as previewMint if called in the
100    ///   same transaction.
101    /// - MUST NOT account for mint limits like those returned from maxMint and should always act as though the mint
102    ///   would be accepted, regardless if the user has enough tokens approved, etc.
103    /// - MUST be inclusive of deposit fees. Integrators should be aware of the existence of deposit fees.
104    /// - MUST NOT revert.
105    ///
106    /// NOTE: any unfavorable discrepancy between convertToAssets and previewMint SHOULD be considered slippage in
107    /// share price or some other type of condition, meaning the depositor will lose assets by minting.
108    function previewMint(uint256 shares) external view returns (uint256 assets);
109
110    /// @notice Mints exactly shares Vault shares to receiver by depositing amount of underlying tokens.
111    /// @dev
112    /// - MUST emit the Deposit event.
113    /// - MAY support an additional flow in which the underlying tokens are owned by the Vault contract before the mint
114    ///   execution, and are accounted for during mint.
115    /// - MUST revert if all of shares cannot be minted (due to deposit limit being reached, slippage, the user not
116    ///   approving enough underlying tokens to the Vault contract, etc).
117    ///
118    /// NOTE: most implementations will require pre-approval of the Vault with the Vault’s underlying asset token.
119    function mint(uint256 shares, address receiver) external returns (uint256 assets);
120
121    /// @notice Returns the maximum amount of the underlying asset that can be withdrawn from the owner balance in the
122    /// Vault, through a withdraw call.
123    /// @dev
124    /// - MUST return a limited value if owner is subject to some withdrawal limit or timelock.
125    /// - MUST NOT revert.
126    function maxWithdraw(address owner) external view returns (uint256 maxAssets);
127
128    /// @notice Allows an on-chain or off-chain user to simulate the effects of their withdrawal at the current block,
129    /// given current on-chain conditions.
130    /// @dev
131    /// - MUST return as close to and no fewer than the exact amount of Vault shares that would be burned in a withdraw
132    ///   call in the same transaction. I.e. withdraw should return the same or fewer shares as previewWithdraw if
133    ///   called
134    ///   in the same transaction.
135    /// - MUST NOT account for withdrawal limits like those returned from maxWithdraw and should always act as though
136    ///   the withdrawal would be accepted, regardless if the user has enough shares, etc.
137    /// - MUST be inclusive of withdrawal fees. Integrators should be aware of the existence of withdrawal fees.
138    /// - MUST NOT revert.
139    ///
140    /// NOTE: any unfavorable discrepancy between convertToShares and previewWithdraw SHOULD be considered slippage in
141    /// share price or some other type of condition, meaning the depositor will lose assets by depositing.
142    function previewWithdraw(uint256 assets) external view returns (uint256 shares);
143
144    /// @notice Burns shares from owner and sends exactly assets of underlying tokens to receiver.
145    /// @dev
146    /// - MUST emit the Withdraw event.
147    /// - MAY support an additional flow in which the underlying tokens are owned by the Vault contract before the
148    ///   withdraw execution, and are accounted for during withdraw.
149    /// - MUST revert if all of assets cannot be withdrawn (due to withdrawal limit being reached, slippage, the owner
150    ///   not having enough shares, etc).
151    ///
152    /// Note that some implementations will require pre-requesting to the Vault before a withdrawal may be performed.
153    /// Those methods should be performed separately.
154    function withdraw(uint256 assets, address receiver, address owner) external returns (uint256 shares);
155
156    /// @notice Returns the maximum amount of Vault shares that can be redeemed from the owner balance in the Vault,
157    /// through a redeem call.
158    /// @dev
159    /// - MUST return a limited value if owner is subject to some withdrawal limit or timelock.
160    /// - MUST return balanceOf(owner) if owner is not subject to any withdrawal limit or timelock.
161    /// - MUST NOT revert.
162    function maxRedeem(address owner) external view returns (uint256 maxShares);
163
164    /// @notice Allows an on-chain or off-chain user to simulate the effects of their redeemption at the current block,
165    /// given current on-chain conditions.
166    /// @dev
167    /// - MUST return as close to and no more than the exact amount of assets that would be withdrawn in a redeem call
168    ///   in the same transaction. I.e. redeem should return the same or more assets as previewRedeem if called in the
169    ///   same transaction.
170    /// - MUST NOT account for redemption limits like those returned from maxRedeem and should always act as though the
171    ///   redemption would be accepted, regardless if the user has enough shares, etc.
172    /// - MUST be inclusive of withdrawal fees. Integrators should be aware of the existence of withdrawal fees.
173    /// - MUST NOT revert.
174    ///
175    /// NOTE: any unfavorable discrepancy between convertToAssets and previewRedeem SHOULD be considered slippage in
176    /// share price or some other type of condition, meaning the depositor will lose assets by redeeming.
177    function previewRedeem(uint256 shares) external view returns (uint256 assets);
178
179    /// @notice Burns exactly shares from owner and sends assets of underlying tokens to receiver.
180    /// @dev
181    /// - MUST emit the Withdraw event.
182    /// - MAY support an additional flow in which the underlying tokens are owned by the Vault contract before the
183    ///   redeem execution, and are accounted for during redeem.
184    /// - MUST revert if all of shares cannot be redeemed (due to withdrawal limit being reached, slippage, the owner
185    ///   not having enough shares, etc).
186    ///
187    /// NOTE: some implementations will require pre-requesting to the Vault before a withdrawal may be performed.
188    /// Those methods should be performed separately.
189    function redeem(uint256 shares, address receiver, address owner) external returns (uint256 assets);
190}