Token Whitelist

The Nullmask contract maintains a whitelist of supported tokens.

Token Types

enum TokenType {
    NOT_ALLOWED,             // Token cannot be deposited
    NATIVE_TOKEN,            // ETH (address(0))
    ERC20,                   // Standard ERC-20 token
    ERC20_FEE_ON_TRANSFER    // ERC-20 with transfer fees
}

Management Functions

setTokenWhitelist(address token, TokenType tokenType)

Set the whitelist status for a single token. Callable by the whitelist manager or the upgrade controller admin.

setTokenWhitelistBatch(address[] tokens, TokenType[] tokenTypes)

Set whitelist status for multiple tokens in one transaction. Arrays must have matching lengths.

setWhitelistManager(address newWhitelistManager)

Transfer the whitelist manager role. Callable by the current manager or upgrade controller admin.

Token Type Effects

Token Type	Deposits	Swaps	Swap Routing
NOT_ALLOWED	Rejected	Rejected	—
NATIVE_TOKEN	Allowed	Allowed	Standard Uniswap functions
ERC20	Allowed	Allowed	Standard Uniswap functions
ERC20_FEE_ON_TRANSFER	Allowed (delta-accounting)	Allowed	SupportingFeeOnTransferTokens variants

Fee-on-Transfer Handling

For tokens with transfer fees, the contract:

1. Records the balance before the transfer

2. Executes the transfer

3. Computes the actual received amount as balanceAfter - balanceBefore

During swaps, if any token in the path is ERC20_FEE_ON_TRANSFER, the contract automatically uses Uniswap's SupportingFeeOnTransferTokens variants.

Events

event TokenWhitelistUpdated(address indexed token, TokenType tokenType);
event WhitelistManagerUpdated(address indexed previousManager, address indexed newManager);