dappconnect-vote-poll-sdk/packages/contracts

status-waku-voting/contracts

Status white label proposal contract

Voting Contract

Voting contract is a smart contract created for purpose of having smart contract that can create and save results of proposals.

This Contract is responsible for creating voting rooms in which you can vote for or against them.

Lifecycle of voting room: 1. initialize voting room. 2. period of time when votes are accepted. 3. voting time is finished votes are no longer accepted.

Types

Main types used for voting are:

• VotingRoom

  Is a type that hold information about voting room for a given proposal

  Fields

  // block at which room was created
  uint256 startBlock; 
  // timestamp in seconds after which new votes won't be accepted
  // when casting votes endAt is compared to block.timestamp
  uint256 endAt; 
  // question of a proposal which voting room describes
  string question;
  // description for proposal
  string description;
  // amount of summed votes for
  uint256 totalVotesFor;
  // amount of summed votes against
  uint256 totalVotesAgainst;
  // list of addresses that already voted
  address[] voters;
  

• Vote

  Is a type that hold information about vote for a given voting room

  Fields

  //address of a voter
  address voter;
  // encoded roomId and type
  // first bit this field is a vote type:
  // 1 is a vote for
  // 0 is a vote against
  // rest of this field is a roomId shifted one bit to 
  // the left
  uint256 roomIdAndType;
  // amount of token used to vote
  uint256 tokenAmount;
  //signature of vote
  bytes32 r;
  bytes32 vs;
  

Constants and variables

• token Variable that holds address of token used for vote verification. It is assigned at contract creation.

• votingLength Variable describing length of voting room in seconds Voting length it is assigned at contract creation.

• EIP712DOMAIN_TYPEHASH Constant holding type hash of EIP712 domain as per EIP712 specification

• VOTE_TYPEHASH Constant holding type hash of Vote as per EIP712 specification

• DOMAIN_SEPARATOR Variable holding hash of domain separator according to EIP712 spec. Assigned at smart contract creation.

• voted this variable holds information if given address voted in a given voting room. So it is a mapping of room id to mapping of addresses to bools which say whether or not given address voted.

• votingRooms Array that holds all voting rooms. roomId of voting room is equivalent to its index in array

Signing with EIP712

This smart contract uses EIP712 for signing vote msg. The structure of typed data for vote messages is as follows:

{
  types: {
      EIP712Domain: [
          { name: 'name', type: 'string' },
          { name: 'version', type: 'string' },
          { name: 'chainId', type: 'uint256' },
          { name: 'verifyingContract', type: 'address' },
      ],
      Vote: [
        { name: 'roomIdAndType', type: 'uint256' },
        { name: 'tokenAmount', type: 'uint256' },
        { name: 'voter', type: 'address' },
      ],
  },
  primaryType: 'Vote',
  domain: {
      name: 'Voting Contract',
      version: '1',
      chainId: chainId,
      verifyingContract: contract.address,
  },
  message: {
      voter: voterAddress,
      tokenAmount: tokenAmount,
      roomIdAndType: roomIdAndType
  }
}

For more information about EIP-712 go to docs

Functions

• constructor(IERC20 _address) Assigns _address to token and generates DOMAIN_SEPARATOR

• getVotingRooms() Returns votingRooms

• getVotingRoomLength() Returns votingRooms length

• getLastNVotingRooms(uint256 amount) Gets last voting rooms returns amount of voting rooms

• getVotingRoomsFrom(uint256 id) Gets voting rooms from given id

• getOngoingVotingRooms() Returns votingRooms in which room.endAt > block.timestamp which means the rooms are still accepting votes. Since votingLength is set at contract creation and never changed, room.endAt is never decreasing with increasing index of votingRoom. Therefore it is enough to check from votingRooms.length up to first element which endAt < block.timestamp

• listRoomVoters(uint256 roomId) Returns a list of voters for a given voting room. Reverts if roomId doesn't exist.

• initializeVotingRoom(string calldata question,string calldata description,uint256 voteAmount) Creates a new voting room with vote for set to voteAmount. First checks if voter has enough tokens to set vote for. Then creates a new voting room. startBlock is set as current block number. endAt is set a current block timestamp plus.votingLength. question is set as argument question. description is set as argument description. totalVotesFor is set as argument voteAmount. Mapping voted of new voting room id of msg.sender is set to true to reflect that message sender has voted on this voting room with voteAmount. votingRooms are appended with newVotingRoom and voters in this new appended element are appended with message sender. After room init VotingRoomStarted is emitted.

• verify(Vote calldata vote,bytes32 r,bytes32 vs) Function used to verify that vote was signed by vote.voter as per EIP712 specification. See docs for more info.

• updateRoomVotes(Vote calldata vote, uint256 roomId) Sets totalVotes amount of voting room with index corresponding to roomId.

  If voting first bit of vote.roomIdAndType is 1 that means that vote is for and vote.tokenAmount is added to votingRooms[roomId].totalVotesFor, otherwise if vote.roomIdAndType is 0 vote.tokenAmount is added to votingRooms[roomId].totalVotesAgainst.

  After that add new address to room voters and updates mapping voted accordingly.

• castVotes(Vote[] calldata votes) Function used to cast votes in rooms. Function accepts an array of votes of type Vote.

  All votes are looped through and verified that votes are:

  • properly signed
  • voter has enough tokens to vote
  • voting room exists
  • voting room hasn't been closed

  Vote verification is as follows. First roomId is decoded from vote.roomIdAndType which means shifting it to the right once.

  Then it is verified that voting room with given roomId exists and isn't closed if not whole function reverts, this is to discourage grouping votes for different voting rooms together (! maybe it should be changed so that votes for multiple voting rooms can be cast ? !).

  After that it is verified that vote has been signed by vote.voter. If not function goes to another vote in array (IDEA: maybe vote verification failed should be emitted ?).

  Then it is checked that vote.voter didn't vote in this vote room before if he did function goes to another voter (IDEA: emit alreadyVoted ?).

  Last check is whether vote.voter has enough tokens to vote. If he does not NotEnoughToken is emitted and function goes to another voter. If he does voting room is updated with updateRoomVotes and VoteCast is emitted.