> ## Documentation Index
> Fetch the complete documentation index at: https://docs.mellow.finance/llms.txt
> Use this file to discover all available pages before exploring further.

# BasicShareManager

### Overview

`BasicShareManager` is a concrete implementation of the abstract `ShareManager`, designed to provide native ERC20-style share accounting within a modular vault system. It handles minting, burning, and tracking balances of vault shares directly through a local ERC20-compatible storage layout, without exposing standard ERC20 interfaces.

This contract is intended for setups where shares are not tokenized on-chain as ERC20s but are still tracked internally using the ERC20Upgradeable storage schema.

### Key Features

* Uses `ShareManager` for permissioning, allocation, and whitelisting logic.
* Maintains balances and total supply using `ERC20Upgradeable.ERC20Storage`.
* Internal mint/burn logic emits `IERC20.Transfer` events (for transparency or compatibility).
* Fully decoupled from standard `ERC20` interface – share transfers are governed by vault queues and mint/burn logic only.

### Storage

ERC20-style balances and supply are stored at a fixed storage slot allowing for migrations BasicShareManager ↔ TokenizedShareManager:

```solidity theme={null}
bytes32 private constant ERC20StorageLocation = 0x52c6...ce00;
```

### Initialization

```solidity theme={null}
function initialize(bytes calldata data) external initializer
```

* Expects a single `bytes32 whitelistMerkleRoot` (used by `ShareManager`).

### View Functions

* `activeShares()`: Returns `_totalSupply` from ERC20 storage.
* `activeSharesOf(account)`: Returns balance of `account`.

### Internal Logic

### `_mintShares(address, uint256)`

* Checks if minting is allowed via `updateChecks`.
* Increments total supply and receiver's balance.
* Emits `IERC20.Transfer(address(0), account, value)`.

Reverts if:

* `account == address(0)`
* Minting is paused or restricted by lockup, whitelist, or blacklist

### `_burnShares(address, uint256)`

* Checks if burning is allowed via `updateChecks`.
* Decreases sender's balance and total supply.
* Emits `IERC20.Transfer(account, address(0), value)`.

Reverts if:

* `account == address(0)`
* `value > account balance`
* Burning is paused or blocked

### Design Notes

* This module deliberately avoids exposing the ERC20 interface, preventing any unintended external transfers or integrations.
* It is intended for internal share accounting within vault systems, where shares are tracked but not tokenized onchain.
* All permissioning logic, including minting, burning, whitelisting, and lockup enforcement, is delegated to the inherited `ShareManager`.
* This implementation is ideal when the vault owner requires non-transferable shares for internal logic, without compliance to ERC20 or ERC4626 standards.
* It is **not appropriate** for setups where shares must be externally transferable, interoperable with third-party protocols, or conform to token standards.