VotesExtended

Inherits: Votes

*Extension of {Votes} that adds checkpoints for delegations and balances. WARNING: While this contract extends {Votes}, valid uses of {Votes} may not be compatible with {VotesExtended} without additional considerations. This implementation of {_transferVotingUnits} must run AFTER the voting weight movement is registered, such that it is reflected on {_getVotingUnits}. Said differently, {VotesExtended} MUST be integrated in a way that calls {_transferVotingUnits} AFTER the asset transfer is registered and balances are updated:

contract VotingToken is Token, VotesExtended {
function transfer(address from, address to, uint256 tokenId) public override {
super.transfer(from, to, tokenId); // <- Perform the transfer first ...
_transferVotingUnits(from, to, 1); // <- ... then call _transferVotingUnits.
}
function _getVotingUnits(address account) internal view override returns (uint256) {
return balanceOf(account);
}
}

{ERC20Votes} and {ERC721Votes} follow this pattern and are thus safe to use with {VotesExtended}.*

State Variables

_userDelegationCheckpoints

mapping(address delegator => Checkpoints.Trace160) private _userDelegationCheckpoints;

_userVotingUnitsCheckpoints

mapping(address account => Checkpoints.Trace208) private _userVotingUnitsCheckpoints;

Functions

getPastDelegate

*Returns the delegate of an account at a specific moment in the past. If the clock() is configured to use block numbers, this will return the value at the end of the corresponding block. Requirements:

• timepoint must be in the past. If operating using block numbers, the block must be already mined.*

function getPastDelegate(address account, uint256 timepoint) public view virtual returns (address);

getPastBalanceOf

*Returns the balanceOf of an account at a specific moment in the past. If the clock() is configured to use block numbers, this will return the value at the end of the corresponding block. Requirements:

• timepoint must be in the past. If operating using block numbers, the block must be already mined.*

function getPastBalanceOf(address account, uint256 timepoint) public view virtual returns (uint256);

_delegate

Delegate all of account's voting units to delegatee. Emits events {IVotes-DelegateChanged} and {IVotes-DelegateVotesChanged}.

function _delegate(address account, address delegatee) internal virtual override;

_transferVotingUnits

Transfers, mints, or burns voting units. To register a mint, from should be zero. To register a burn, to should be zero. Total supply of voting units will be adjusted with mints and burns.

function _transferVotingUnits(address from, address to, uint256 amount) internal virtual override;