feat: erc7540 vault deposit flow

solidity/src/vaults/ValenceXCV.sol

@@ -0,0 +1,265 @@
+// SPDX-License-Identifier: Apache-2.0
+pragma solidity ^0.8.28;
+
+import {ERC4626Upgradeable} from "@openzeppelin-contracts-upgradeable/token/ERC20/extensions/ERC4626Upgradeable.sol";
+import {BaseAccount} from "../accounts/BaseAccount.sol";
+import {Math} from "@openzeppelin/contracts/utils/math/Math.sol";
+import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
+import {OwnableUpgradeable} from "@openzeppelin-contracts-upgradeable/access/OwnableUpgradeable.sol";
+import {Initializable} from "@openzeppelin-contracts-upgradeable/proxy/utils/Initializable.sol";
+import {SafeERC20} from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
+import {IERC7540Operator} from "../vaults/interfaces/IERC7540Operator.sol";
+import {IValenceVaultStrategist} from "../vaults/interfaces/IValenceVaultStrategist.sol";
+
+contract ValenceXCV is
+    Initializable,
+    ERC4626Upgradeable,
+    IERC7540Operator,
+    OwnableUpgradeable,
+    IValenceVaultStrategist
+{
+    using Math for uint256;
+
+    error InvalidSharePrice();
+    error OnlyStrategistAllowed();
+    error NotControllerOrOperator();
+    error DepositAccountNotSet();
+    error StrategistNotSet();
+    error ZeroDepositAmount();
+    error StaleSharePrice();
+    error InvalidSharePriceMaxAge();
+    error SharePriceChangeDeltaTooLarge();
+
+    /// @dev The precision factor for one share, equivalent to 10^decimals().
+    uint256 internal ONE_SHARE;
+
+    /// The current price of one share in terms of the underlying asset.
+    uint256 public sharePrice;
+    /// The timestamp of the last share price update.
+    uint256 public lastUpdateTimestamp;
+    /// The maximum age of the share price in seconds before it is considered stale.
+    uint256 public sharePriceMaxAge;
+    /// Max allowed price change in a single share price update, in bips (1/100th of 1%)
+    uint256 public maxPriceChange;
+
+    /// The address of the authorized strategist who can update the share price.
+    address public strategist;
+
+    /// The Valence account contract that holds the deposited funds.
+    address public depositAccount;
+
+    /// Mapping of controllers to their approved operators.
+    mapping(address controller => mapping(address operator => bool))
+        public operators;
+
+    /// @dev Restricts function access to strategist
+    modifier onlyStrategist() {
+        if (msg.sender != strategist) {
+            revert OnlyStrategistAllowed();
+        }
+        _;
+    }
+
+    /// @dev Restricts function access to the controller or any operators
+    /// approved by the controller
+    /// @param controller address of the target position owner
+    modifier onlyControllerOrOperator(address controller) {
+        if (controller != msg.sender && !operators[controller][msg.sender]) {
+            revert NotControllerOrOperator();
+        }
+        _;
+    }
+
+    // TODO: think whether this should instead be a hard pause (in state) that
+    // would require owner intervention
+    /// @dev Restricts function to cases where the share price is up to date
+    modifier onlyWhenSharePriceNotStale() {
+        if (block.timestamp - lastUpdateTimestamp > sharePriceMaxAge) {
+            revert StaleSharePrice();
+        }
+        _;
+    }
+
+    constructor() {
+        // _disableInitializers();
+    }
+
+    /// Initializes the vault.
+    /// @param _owner The owner of the vault.
+    /// @param strategistAddress The address of the strategist.
+    /// @param underlying The address of the underlying asset token.
+    /// @param depositAccountAddress The address of the deposit account.
+    /// @param vaultTokenName The name of the vault token.
+    /// @param vaultTokenSymbol The symbol of the vault token.
+    /// @param startSharePrice The initial share price.
+    /// @param maxSharePriceAge The maximum age of the share price in seconds.
+    function initialize(
+        address _owner,
+        address strategistAddress,
+        address underlying,
+        address depositAccountAddress,
+        string memory vaultTokenName,
+        string memory vaultTokenSymbol,
+        uint256 startSharePrice,
+        uint256 maxSharePriceAge,
+        uint256 maxPriceChangeBips
+    ) external initializer {
+        // initialize the vault share token
+        __ERC20_init(vaultTokenName, vaultTokenSymbol);
+        // initialize the underlying (deposit) token
+        __ERC4626_init(IERC20(underlying));
+        // set up ownership
+        __Ownable_init(_owner);
+
+        if (startSharePrice == 0) revert InvalidSharePrice();
+        sharePrice = startSharePrice;
+        lastUpdateTimestamp = block.timestamp;
+        maxPriceChange = maxPriceChangeBips;
+
+        if (maxSharePriceAge == 0) revert InvalidSharePriceMaxAge();
+        sharePriceMaxAge = maxSharePriceAge;
+
+        if (depositAccountAddress == address(0)) revert DepositAccountNotSet();
+        depositAccount = depositAccountAddress;
+
+        if (strategistAddress == address(0)) revert StrategistNotSet();
+        strategist = strategistAddress;
+
+        // set the share precision based on the underlying token decimals
+        ONE_SHARE = 10 ** decimals();
+    }
+
+    // ========================================================================
+    // ========================= ERC-7540 OPERATOR ============================
+    // ========================================================================
+
+    /// Checks whether a given address is an approved operator for a controller
+    /// @param controller The address of the controller
+    /// @param operator The address of the operator to check
+    /// @return A boolean indicating whether the operator is approved
+    function isOperator(
+        address controller,
+        address operator
+    ) external view returns (bool) {
+        return operators[controller][operator];
+    }
+
+    /// Approves or revokes an operator for the caller
+    /// @param operator The address of the operator
+    /// @param approved A boolean indicating whether to approve or revoke the operator
+    /// @return A boolean indicating the success of the operation (always true)
+    function setOperator(
+        address operator,
+        bool approved
+    ) external returns (bool) {
+        // set the operator status
+        operators[msg.sender][operator] = approved;
+        emit OperatorSet(msg.sender, operator, approved);
+        return true;
+    }
+
+    // ========================================================================
+    // ============================ DEPOSIT LANE ==============================
+    // ========================================================================
+
+    /// Sets the share price. Can only be called by the strategist
+    /// @param newSharePrice The new share price
+    function setSharePrice(uint256 newSharePrice) external onlyStrategist {
+        // setting share price to 0 would allow for infinite mint
+        if (newSharePrice == 0) revert InvalidSharePrice();
+
+        uint256 oldSharePrice = sharePrice;
+        // get the absolute difference between the new and old share prices
+        uint256 delta = newSharePrice > oldSharePrice
+            ? newSharePrice - oldSharePrice
+            : oldSharePrice - newSharePrice;
+
+        // verify that the delta is within our tolerance
+        // maxPriceChange is expressed in bips, so we multiply the delta by 10000
+        if ((delta * 10000) / oldSharePrice > maxPriceChange) {
+            revert SharePriceChangeDeltaTooLarge();
+        }
+
+        sharePrice = newSharePrice;
+        lastUpdateTimestamp = block.timestamp;
+
+        emit SharePriceUpdated(newSharePrice, lastUpdateTimestamp);
+    }
+
+    /// Converts a given amount of assets to shares
+    /// @param assets The amount of assets to convert
+    /// @param rounding The rounding direction
+    /// @return The corresponding amount of shares
+    function _convertToShares(
+        uint256 assets,
+        Math.Rounding rounding
+    ) internal view override returns (uint256) {
+        return assets.mulDiv(ONE_SHARE, sharePrice, rounding);
+    }
+
+    /// Deposits assets into the vault and mints shares for the receiver.
+    /// This is the ERC-4626 compliant deposit function.
+    /// @dev calls into deposit(assets, receiver, controller) with controller = msg.sender
+    /// @param assets The amount of assets to deposit
+    /// @param receiver The address that will receive the shares
+    /// @return shares The amount of shares minted
+    function deposit(
+        uint256 assets,
+        address receiver
+    ) public override returns (uint256 shares) {
+        return deposit(assets, receiver, msg.sender);
+    }
+
+    /// Deposits assets into the vault and mints shares for the receiver.
+    /// This is the ERC-7540 compliant deposit function.
+    /// @param assets The amount of assets to deposit
+    /// @param receiver The address that will receive the shares
+    /// @param controller The address of the controller on whose behalf the deposit is made
+    /// @return shares The amount of shares minted
+    function deposit(
+        uint256 assets,
+        address receiver,
+        address controller
+    )
+        public
+        onlyWhenSharePriceNotStale
+        onlyControllerOrOperator(controller)
+        returns (uint256 shares)
+    {
+        // zero deposits are not allowed
+        if (assets == 0) {
+            revert ZeroDepositAmount();
+        }
+
+        // calculate the shares to be minted based on provided assets
+        // and the current share price
+        shares = convertToShares(assets);
+
+        _deposit(controller, receiver, assets, shares);
+    }
+
+    /// Internal deposit logic. Transfers assets to the deposit account and mints shares.
+    /// Only modification to the default ERC-4626 is that deposited assets are escrowed
+    /// to the deposit account (external contract).
+    /// @param caller The address that initiated the deposit
+    /// @param receiver The address that will receive the shares
+    /// @param assets The amount of assets to deposit
+    /// @param shares The amount of shares to mint
+    function _deposit(
+        address caller,
+        address receiver,
+        uint256 assets,
+        uint256 shares
+    ) internal override {
+        // escrow the deposited assets to the deposit account (external contract)
+        SafeERC20.safeTransferFrom(
+            IERC20(asset()),
+            receiver,
+            depositAccount,
+            assets
+        );
+        _mint(receiver, shares);
+
+        emit Deposit(caller, receiver, assets, shares);
+    }
+}

solidity/src/vaults/interfaces/IERC7540Operator.sol

@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: Apache-2.0
+pragma solidity ^0.8.28;
+
+// interface for operator functionality inspired by ERC-6909, as described in ERC-7540:
+// https://eips.ethereum.org/EIPS/eip-7540#operators
+
+interface IERC7540Operator {
+    /**
+     * @dev Emitted when `controller` grants or revokes operator status for a `spender`.
+     */
+    event OperatorSet(
+        address indexed controller,
+        address indexed operator,
+        bool approved
+    );
+
+    /**
+     * @dev Returns true if `operator` is set as an operator for `controller`.
+     */
+    function isOperator(
+        address controller,
+        address operator
+    ) external view returns (bool);
+
+    /**
+     * @dev Grants or revokes `operator` rights to issue ERC-7540 requests on behalf of the caller (controller).
+     *
+     * Returns true if the operation was successful.
+     */
+    function setOperator(
+        address operator,
+        bool approved
+    ) external returns (bool);
+}

solidity/src/vaults/interfaces/IValenceVaultStrategist.sol

@@ -0,0 +1,16 @@
+// SPDX-License-Identifier: Apache-2.0
+pragma solidity ^0.8.28;
+
+interface IValenceVaultStrategist {
+    /// @dev Emitted on successful share price update by the strategist.
+    /// @param sharePrice newly posted share price
+    /// @param updateTimestamp block.time of the update
+    event SharePriceUpdated(
+        uint256 indexed sharePrice,
+        uint256 indexed updateTimestamp
+    );
+
+    /// Sets the share price.
+    /// @param newSharePrice The new share price.
+    function setSharePrice(uint256 newSharePrice) external;
+}