FeeManager

Modular, upgradeable fee management contract for vaults.

The FeeManager is responsible for managing and calculating various fee types in a vault system, including deposit, redemption, performance, and protocol fees. It uses a flexible architecture with deterministic storage slots (via SlotLibrary) and supports per-vault configurations.

Key Responsibilities

  • Configures and stores global fee settings (in D6 precision).

  • Tracks vault-specific state (base asset, min price, timestamp).

  • Computes:

    • Deposit Fee: Fee charged on asset deposit.

    • Redeem Fee: Fee charged on share redemption.

    • Performance Fee: Fee based on drop in price (assets * price = shares)

    • Protocol Fee: Time-based fee accrued per vault.

  • Provides administrative controls to update fee settings and vault metadata.

Storage

Uses an isolated storage slot per deployment instance, computed deterministically using SlotLibrary.getSlot("FeeManager", name, version), ensuring safety and upgradability.

Each vault is associated with:

  • baseAsset: Reference token used for performance fee calculation.

  • minPriceD18: Minimum price recorded (used for performance fee calculation).

  • timestamps: Last update timestamp for time-based fee accrual.

Fee Calculation Logic

calculateDepositFee(uint256 shares) → uint256

Computes a linear fee as shares * depositFeeD6 / 1e6.

calculateRedeemFee(uint256 shares) → uint256

Computes a linear fee as shares * redeemFeeD6 / 1e6.

calculateFee(...) → uint256 shares

Calculates the total fee to be charged based on:

  • Performance: If current priceD18 below minPriceD18, applies performanceFeeD6 as (minPriceD18 - priceD18) * performanceFeeD6 * totalShares / 1e24.

  • Protocol: Time-weighted fee based on block.timestamp - timestamps[vault], computed as totalShares * protocolFee * (block.timestamp - timestamps[vault]) / (365 * 24 * 3600 * 1e6)

All fees are paid in shares of the vault (not assets).

Access Control

  • Only the owner (defined during initialization) can modify fee parameters or vault configurations.

  • Calls to initialize(...) must come from the factory and include all required setup parameters.

Events

  • Initialized(bytes data): Emitted after initialization.

  • SetFeeRecipient(address feeRecipient): On recipient update.

  • SetFees(...): On any fee change.

  • SetBaseAsset(...): When base asset is configured per vault.

  • UpdateState(...): On state update used for protocol/performance fees.

Errors

  • ZeroAddress(): Thrown if an address input is zero.

  • InvalidFees(...): When the combined fee rate exceeds 100% (1e6 D6).

  • BaseAssetAlreadySet(...): Prevents base asset override if already set.

Lifecycle

  1. Constructor: Sets storage slot based on name/version.

  2. Initialization (via initialize(bytes)): Sets owner, recipient, and fees.

  3. Fee Updates: Admin can update recipient and fee parameters.

  4. Vault Hooks:

    • updateState(asset, price): Vaults call this to refresh timestamp and min price.

    • setBaseAsset: Called once per vault to register its performance reference token.

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