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refactor: inline logic
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@Amxx
Amxx committed May 30, 2024
1 parent f1b71bc commit 3f1c13b
Showing 1 changed file with 42 additions and 85 deletions.
127 changes: 42 additions & 85 deletions contracts/governance/extensions/GovernorCountingFractional.sol
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Original file line number Diff line number Diff line change
Expand Up @@ -102,26 +102,31 @@ abstract contract GovernorCountingFractional is Governor {
/**
* @dev See {Governor-_countVote}. Function that records the delegate's votes.
*
* Executing this function consume's the delegate's weight on the proposal. This weight can be distributed amongst
* the 3 options (Against, For, Abstain) by specifying a Fractional `support`.
* Executing this function consumes (part of) the delegate's weight on the proposal. This weight can be
* distributed amongst the 3 options (Against, For, Abstain) by specifying a Fractional `support`.
*
* When support is anything other than Fractional, the `params` argument must be empty and the delegate's full remaining
* weight is cast for the specified `support` option, as in {GovernorCountingSimple} and following the `VoteType`
* enum from Governor Bravo.
* This counting module supports two vote casting modes: nominal and fractional.
*
* Given a Fractional `support`, the `params` argument must be tree packed `uint128` values representing the weight
* the delegate assigns to Against, For, and Abstain respectively. This format can be produced using:
* - Voting in "nomainal" mode is achieved by setting `support` to on of the 3 bravo options (Against, For,
* Abstain). In this mode, the `params` argument must be empty and the delegate's full remaining weight is cast
* for the specified `support` option, as in {GovernorCountingSimple} and following the `VoteType` enum from
* Governor Bravo. As a consequence, no vote weight remains unspend so no further voting is possible (for this
* `proposalId` and this `account`).
*
* - Voting in "fractional" mode is achieved by setting `support` to `type(uint8).max` (255). In this mode, the
* `params` argument must be tree packed `uint128` values representing the weight the delegate assigns to each
* support option (Against, For, and Abstain respectively). This format can be produced using:
*
* `abi.encodePacked(uint128(againstVotes), uint128(forVotes), uint128(abstainVotes))`
*
* The sum total of the three decoded vote weights _must_ be less than or equal to the delegate's remaining weight
* on the proposal, i.e. their checkpointed total weight minus votes already cast on the proposal.
*
* NOTE: Consider the number of votes is restricted to 128 bits. Depending on how many decimals the underlying token
* has, a single voter may require to split their vote into multiple transactions. For precision higher than
* ~30 decimals, large token holders may require an exponentially large number of transactions to cast their vote.
*
* See `_countVoteNominal` and `_countVoteFractional` for more details.
* NOTE: Consider that fractional voting restricts the number of casted vote (in each category) to 128 bits.
* Depending on how many decimals the underlying token has, a single voter may require to split their vote into
* multiple vote operations. For precision higher than ~30 decimals, large token holders may require an
* potentially large number of calls to cast all their votes. The voter has the possibility to cast all the
* remaining votes in a single operation using the traditional "bravo" vote.
*/
function _countVote(
uint256 proposalId,
Expand All @@ -136,78 +141,45 @@ abstract contract GovernorCountingFractional is Governor {
revert GovernorAlreadyCastVote(account);
}

uint256 againstVotes = 0;
uint256 forVotes = 0;
uint256 abstainVotes = 0;

// For clarity of event indexing, fractional voting must be clearly advertised in the "support" field.
//
// Supported `support` value must be:
// - "Full" voting: `support = 0` (Against), `1` (For) or `2` (Abstain), with empty params.
// - "Fractional" voting: `support = 255`, with 48 bytes params.
if (support <= uint8(GovernorCountingSimple.VoteType.Abstain)) {
if (support == uint8(GovernorCountingSimple.VoteType.Against)) {
if (params.length != 0) revert GovernorInvalidVoteParams();
againstVotes = remainingWeight;
} else if (support == uint8(GovernorCountingSimple.VoteType.For)) {
if (params.length != 0) revert GovernorInvalidVoteParams();
forVotes = remainingWeight;
} else if (support == uint8(GovernorCountingSimple.VoteType.Abstain)) {
if (params.length != 0) revert GovernorInvalidVoteParams();
return _countVoteNominal(proposalId, account, support, remainingWeight);
abstainVotes = remainingWeight;
} else if (support == VOTE_TYPE_FRACTIONAL) {
return _countVoteFractional(proposalId, account, params, remainingWeight);
// The `params` argument is expected to be three packed `uint128`:
// `abi.encodePacked(uint128(againstVotes), uint128(forVotes), uint128(abstainVotes))`
if (params.length != 0x30) revert GovernorInvalidVoteParams();

assembly ("memory-safe") {
againstVotes := shr(128, mload(add(params, 0x20)))
forVotes := shr(128, mload(add(params, 0x30)))
abstainVotes := shr(128, mload(add(params, 0x40)))
}
} else {
revert GovernorInvalidVoteType();
}
}

/**
* @dev Record votes with full weight cast for `support`.
*
* Because this function votes with the delegate's remaining weight, it can only be called once per proposal and
* thus does not require any replay protection.
*/
function _countVoteNominal(
uint256 proposalId,
address account,
uint8 support,
uint256 weight
) private returns (uint256) {
ProposalVote storage details = _proposalVotes[proposalId];
details.usedVotes[account] += weight;

if (support == uint8(GovernorCountingSimple.VoteType.Against)) {
details.againstVotes += weight;
} else if (support == uint8(GovernorCountingSimple.VoteType.For)) {
details.forVotes += weight;
} else if (support == uint8(GovernorCountingSimple.VoteType.Abstain)) {
details.abstainVotes += weight;
}

return weight;
}

/**
* @dev Count votes with fractional weight.
*
* The `params` argument is expected to be three packed `uint128`:
* `abi.encodePacked(uint128(againstVotes), uint128(forVotes), uint128(abstainVotes))`
*
* This function can be called multiple times for the same account and proposal (i.e. partial/rolling votes are
* allowed). For example, an account with total weight of 10 could call this function three times with the
* following vote data:
*
* * Against: 1, For: 0, Abstain: 2
* * Against: 3, For: 1, Abstain: 0
* * Against: 1, For: 1, Abstain: 1
*
* Casting votes like this will make the calling account to cast a total of 5 `Against` votes, 2 `For` votes
* and 3 `Abstain` votes. Though partial, votes are still final once cast and cannot be changed or overridden.
* Subsequent partial votes simply increment existing totals.
*/
function _countVoteFractional(
uint256 proposalId,
address account,
bytes memory params,
uint256 weight
) private returns (uint256) {
(uint128 againstVotes, uint128 forVotes, uint128 abstainVotes) = _unpackParams(params);

// check parsed arguments are valid
uint256 usedWeight = againstVotes + forVotes + abstainVotes;
if (usedWeight > weight) {
revert GovernorExceedRemainingWeight(account, usedWeight, weight);
if (usedWeight > remainingWeight) {
revert GovernorExceedRemainingWeight(account, usedWeight, remainingWeight);
}

// update votes tracking
ProposalVote storage details = _proposalVotes[proposalId];
if (againstVotes > 0) {
details.againstVotes += againstVotes;
Expand All @@ -222,19 +194,4 @@ abstract contract GovernorCountingFractional is Governor {

return usedWeight;
}

function _unpackParams(
bytes memory data
) private pure returns (uint128 againstVotes, uint128 forVotes, uint128 abstainVotes) {
if (data.length != 0x30) {
revert GovernorInvalidVoteParams();
}

assembly ("memory-safe") {
let ptr := add(data, 0x20)
againstVotes := shr(128, mload(ptr))
forVotes := shr(128, mload(add(ptr, 0x10)))
abstainVotes := shr(128, mload(add(ptr, 0x20)))
}
}
}

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