GovernanceWrappedERC20

Contract · src/erc20/GovernanceWrappedERC20.sol

Explained in: Governance tokens

Author: Aragon X

Inherits: IGovernanceWrappedERC20, Initializable, ERC165Upgradeable, ERC20VotesUpgradeable, ERC20WrapperUpgradeable

Wraps an existing ERC-20 token by inheriting from ERC20WrapperUpgradeable and allows using it for voting by inheriting from ERC20VotesUpgradeable. The latter is compatible with OpenZeppelin's Votes interface. The contract supports meta transactions. To use an amount of underlying tokens for voting, the token owner must:

1. call approve for the tokens to be used by this contract
2. call depositFor to wrap them, which safely transfers the underlying ERC-20 tokens to the contract and mints wrapped ERC-20 tokens. To get the ERC-20 tokens back, the owner of the wrapped tokens can call withdrawFor, which burns the wrapped ERC-20 tokens and safely transfers the underlying tokens back to the owner.

Dev: This contract intentionally has no public mint functionality because this is the responsibility of the underlying ERC-20 token contract.

security-contact: sirt@aragon.org

Constructor

constructor

constructor(IERC20Upgradeable _token, string _name, string _symbol)

Calls the initialize function.

Parameter	Type	Description
_token	IERC20Upgradeable	The underlying ERC-20 token.
_name	string	The name of the wrapped token.
_symbol	string	The symbol of the wrapped token.

Functions

allowance

function allowance(address owner, address spender) external view returns (uint256)

Selector: 0xdd62ed3e

Dev: See {IERC20-allowance}.

approve

function approve(address spender, uint256 amount) external returns (bool)

Selector: 0x095ea7b3

Dev: See {IERC20-approve}.

NOTE: If amount is the maximum uint256, the allowance is not updated on transferFrom. This is semantically equivalent to an infinite approval.

Requirements:

• spender cannot be the zero address.

balanceOf

function balanceOf(address account) external view returns (uint256)

Selector: 0x70a08231

Dev: See {IERC20-balanceOf}.

checkpoints

function checkpoints(
    address account,
    uint32 pos
) external view returns (ERC20VotesUpgradeable.Checkpoint)

Selector: 0xf1127ed8

Dev: Get the pos-th checkpoint for account.

Returns	Type	Description
[0]	ERC20VotesUpgradeable.Checkpoint

clock

function clock() external view returns (uint48)

Selector: 0x91ddadf4

Dev: Clock used for flagging checkpoints. Can be overridden to implement timestamp based checkpoints (and voting).

CLOCK_MODE

function CLOCK_MODE() external view returns (string)

Selector: 0x4bf5d7e9

Dev: Description of the clock

decimals

function decimals() external view returns (uint8)

Selector: 0x313ce567

Dev: Uses the decimals of the underlying ERC-20 token.

decreaseAllowance

function decreaseAllowance(address spender, uint256 subtractedValue) external returns (bool)

Selector: 0xa457c2d7

Dev: Atomically decreases the allowance granted to spender by the caller.

This is an alternative to {approve} that can be used as a mitigation for problems described in {IERC20-approve}.

Emits an {Approval} event indicating the updated allowance.

Requirements:

• spender cannot be the zero address.
• spender must have allowance for the caller of at least subtractedValue.

delegate

function delegate(address delegatee) external

Selector: 0x5c19a95c

Dev: Delegate votes from the sender to delegatee.

delegateBySig

function delegateBySig(
    address delegatee,
    uint256 nonce,
    uint256 expiry,
    uint8 v,
    bytes32 r,
    bytes32 s
) external

Selector: 0xc3cda520

Dev: Delegates votes from signer to delegatee

delegates

function delegates(address account) external view returns (address)

Selector: 0x587cde1e

Dev: Get the address account is currently delegating to.

depositFor

function depositFor(address account, uint256 amount) external returns (bool)

Selector: 0x2f4f21e2

Deposits an amount of underlying token and mints the corresponding number of wrapped tokens for a receiving address.

Parameter	Type	Description
account	address	The address receiving the minted, wrapped tokens.
amount	uint256	The amount of tokens to deposit.

DOMAIN_SEPARATOR

function DOMAIN_SEPARATOR() external view returns (bytes32)

Selector: 0x3644e515

Dev: Returns the domain separator used in the encoding of the signature for {permit}, as defined by {EIP712}.

eip712Domain

function eip712Domain() external view returns (bytes1 fields, string name, string version, uint256 chainId, address verifyingContract, bytes32 salt, uint256[] extensions)

Selector: 0x84b0196e

Dev: See {EIP-5267}.

Available since v4.9.

getPastTotalSupply

function getPastTotalSupply(uint256 timepoint) external view returns (uint256)

Selector: 0x8e539e8c

Dev: Retrieve the totalSupply at the end of timepoint. Note, this value is the sum of all balances. It is NOT the sum of all the delegated votes!

Requirements:

• timepoint must be in the past

getPastVotes

function getPastVotes(address account, uint256 timepoint) external view returns (uint256)

Selector: 0x3a46b1a8

Dev: Retrieve the number of votes for account at the end of timepoint.

Requirements:

• timepoint must be in the past

getVotes

function getVotes(address account) external view returns (uint256)

Selector: 0x9ab24eb0

Dev: Gets the current votes balance for account

increaseAllowance

function increaseAllowance(address spender, uint256 addedValue) external returns (bool)

Selector: 0x39509351

Dev: Atomically increases the allowance granted to spender by the caller.

This is an alternative to {approve} that can be used as a mitigation for problems described in {IERC20-approve}.

Emits an {Approval} event indicating the updated allowance.

Requirements:

• spender cannot be the zero address.

initialize

function initialize(IERC20Upgradeable _token, string _name, string _symbol) external

Selector: 0x90657147

Initializes the contract.

Parameter	Type	Description
_token	IERC20Upgradeable	The underlying ERC-20 token.
_name	string	The name of the wrapped token.
_symbol	string	The symbol of the wrapped token.

name

function name() external view returns (string)

Selector: 0x06fdde03

Dev: Returns the name of the token.

nonces

function nonces(address owner) external view returns (uint256)

Selector: 0x7ecebe00

Dev: Returns the current nonce for owner. This value must be included whenever a signature is generated for {permit}. Every successful call to {permit} increases owner's nonce by one. This prevents a signature from being used multiple times.

numCheckpoints

function numCheckpoints(address account) external view returns (uint32)

Selector: 0x6fcfff45

Dev: Get number of checkpoints for account.

permit

function permit(
    address owner,
    address spender,
    uint256 value,
    uint256 deadline,
    uint8 v,
    bytes32 r,
    bytes32 s
) external

Selector: 0xd505accf

Dev: Sets value as the allowance of spender over owner's tokens, given owner's signed approval. IMPORTANT: The same issues {IERC20-approve} has related to transaction ordering also apply here. Emits an {Approval} event. Requirements: - spender cannot be the zero address. - deadline must be a timestamp in the future. - v, r and s must be a valid secp256k1 signature from owner over the EIP712-formatted function arguments. - the signature must use owner's current nonce (see {nonces}). For more information on the signature format, see the https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP section]. CAUTION: See Security Considerations above.

supportsInterface

function supportsInterface(bytes4 _interfaceId) external view returns (bool)

Selector: 0x01ffc9a7

Checks if this or the parent contract supports an interface by its ID.

Parameter	Type	Description
_interfaceId	bytes4	The ID of the interface.

symbol

function symbol() external view returns (string)

Selector: 0x95d89b41

Dev: Returns the symbol of the token, usually a shorter version of the name.

totalSupply

function totalSupply() external view returns (uint256)

Selector: 0x18160ddd

Dev: See {IERC20-totalSupply}.

transfer

function transfer(address to, uint256 amount) external returns (bool)

Selector: 0xa9059cbb

Dev: See {IERC20-transfer}.

Requirements:

• to cannot be the zero address.
• the caller must have a balance of at least amount.

transferFrom

function transferFrom(address from, address to, uint256 amount) external returns (bool)

Selector: 0x23b872dd

Dev: See {IERC20-transferFrom}.

Emits an {Approval} event indicating the updated allowance. This is not required by the EIP. See the note at the beginning of {ERC20}.

NOTE: Does not update the allowance if the current allowance is the maximum uint256.

Requirements:

• from and to cannot be the zero address.
• from must have a balance of at least amount.
• the caller must have allowance for from's tokens of at least amount.

underlying

function underlying() external view returns (IERC20Upgradeable)

Selector: 0x6f307dc3

Dev: Returns the address of the underlying ERC-20 token that is being wrapped.

withdrawTo

function withdrawTo(address account, uint256 amount) external returns (bool)

Selector: 0x205c2878

Withdraws an amount of underlying tokens to a receiving address and burns the corresponding number of wrapped tokens.

Parameter	Type	Description
account	address	The address receiving the withdrawn, underlying tokens.
amount	uint256	The amount of underlying tokens to withdraw.

Events

Approval

event Approval(address indexed owner, address indexed spender, uint256 value)

Dev: Emitted when the allowance of a spender for an owner is set by a call to {approve}. value is the new allowance.

DelegateChanged

event DelegateChanged(
    address indexed delegator,
    address indexed fromDelegate,
    address indexed toDelegate
)

Dev: Emitted when an account changes their delegate.

DelegateVotesChanged

event DelegateVotesChanged(
    address indexed delegate,
    uint256 previousBalance,
    uint256 newBalance
)

Dev: Emitted when a token transfer or delegate change results in changes to a delegate's number of votes.

EIP712DomainChanged

event EIP712DomainChanged()

Dev: MAY be emitted to signal that the domain could have changed.

Initialized

event Initialized(uint8 version)

Dev: Triggered when the contract has been initialized or reinitialized.

Transfer

event Transfer(address indexed from, address indexed to, uint256 value)

Dev: Emitted when value tokens are moved from one account (from) to another (to).

Note that value may be zero.

Structs

Checkpoint

Inherited from ERC20VotesUpgradeable.

struct Checkpoint {
    uint32 fromBlock;
    uint224 votes;
}