Merge pull request #589 from PolymathNetwork/commit-reveal-voting

PLCR voting module

contracts/modules/Experimental/Checkpoints/PLCRVotingCheckpoint.sol

@@ -0,0 +1,324 @@
+pragma solidity ^0.5.0;
+
+import "../../Module.sol";
+import "openzeppelin-solidity/contracts/math/SafeMath.sol";
+
+contract PLCRVotingCheckpoint is Module {
+
+    using SafeMath for uint256;
+
+    enum Stage { PREP, COMMIT, REVEAL, RESOLVED }
+
+    struct Ballot {
+        uint256 quorum;       // Should be a multiple of 10 ** 16
+        uint256 checkpointId;
+        uint64 commitDuration;
+        uint64 revealDuration;
+        uint64 startTime;
+        uint24 totalProposals;
+        uint32 totalVoters;
+        bool isActive;
+        mapping(uint256 => uint256) weightedVote;
+        mapping(address => Vote) proposalToVote;
+    }
+
+    struct Vote {
+        uint256 voteOption;
+        bytes32 secretVote;
+    }
+
+    Ballot[] ballots;
+
+    event VoteCommit(address indexed _voter, uint256 _weight, uint256 indexed _ballotId, bytes32 _secretVote);
+    event BallotCreated(
+        uint256 indexed _ballotId,
+        uint256 _commitDuration,
+        uint256 _revealDuration,
+        uint256 _noOfProposals,
+        uint256 _startTime,
+        uint256 _proposedQuorum,
+        uint256 indexed _checkpointId
+    );
+    event VoteRevealed(address indexed _voter, uint256 _weight, uint256 indexed _ballotId, uint256 _choiceOfProposal, uint256 _salt, bytes32 _secretVote);
+    event BallotStatusChanged(uint256 indexed _ballotId, bool _newStatus);
+
+    constructor(address _securityToken, address _polyAddress)
+    public
+    Module(_securityToken, _polyAddress)
+    {
+
+    } 
+
+    /**
+     * @notice Use to create the ballot
+     * @param _commitDuration Unix time period till the voters commit there vote
+     * @param _revealDuration Unix time period till the voters reveal there vote starts when commit duration ends
+     * @param _noOfProposals Total number of proposal used in the ballot. In general it is 2 (For & Against)
+     * @param _proposedQuorum Minimum number of weight vote requires to win a election.
+     */
+    function createBallot(
+        uint256 _commitDuration,
+        uint256 _revealDuration,
+        uint256 _noOfProposals,
+        uint256 _proposedQuorum
+    )   
+        external
+        withPerm(ADMIN)
+    {
+        uint256 startTime = now;
+        uint256 checkpointId = ISecurityToken(securityToken).createCheckpoint();
+        _createBallotWithCheckpoint(_commitDuration, _revealDuration, _noOfProposals, _proposedQuorum, checkpointId, startTime);
+    }
+
+    /**
+     * @notice Use to create the ballot
+     * @param _commitDuration Unix time period till the voters commit there vote
+     * @param _revealDuration Unix time period till the voters reveal there vote starts when commit duration ends
+     * @param _noOfProposals Total number of proposal used in the ballot. In general it is 2 (For & Against)
+     * @param _proposedQuorum Minimum number of weight vote requires to win a election.
+     * @param _checkpointId Valid checkpoint Id
+     * @param _startTime startTime of the ballot
+     */
+    function createCustomBallot(
+        uint256 _commitDuration,
+        uint256 _revealDuration,
+        uint256 _noOfProposals,
+        uint256 _proposedQuorum,
+        uint256 _checkpointId,
+        uint256 _startTime
+    )
+        external
+        withPerm(ADMIN)
+    {
+        require(_checkpointId <= ISecurityToken(securityToken).currentCheckpointId(), "Invalid checkpoint Id");
+        _createBallotWithCheckpoint(_commitDuration, _revealDuration, _noOfProposals, _proposedQuorum, _checkpointId, _startTime);
+    }
+
+    function _createBallotWithCheckpoint(
+        uint256 _commitDuration,
+        uint256 _revealDuration,
+        uint256 _totalProposals,
+        uint256 _proposedQuorum,
+        uint256 _checkpointId,
+        uint256 _startTime
+    )
+        internal
+    {
+        // Sanity checks
+        _validValueCheck(_commitDuration);
+        _validValueCheck(_revealDuration);
+        _validValueCheck(_proposedQuorum);
+        // Overflow check
+        require(
+            uint64(_commitDuration) == _commitDuration && 
+            uint64(_revealDuration) == _revealDuration &&
+            uint64(_startTime) == _startTime &&
+            uint24(_totalProposals) == _totalProposals,
+            "Parameter values get overflowed"
+        );
+        require(_startTime >= now, "Invalid start time");
+        // Total no of proposals always greater than 2 it means minimum valid
+        // proposal id will be 0 or 1. Proposal Id should be start from 0 instead of 1.
+        require(_totalProposals > 1, "Invalid number of totalProposals");
+        uint256 _ballotId = ballots.length;
+        ballots.push(Ballot(
+            _proposedQuorum,
+            _checkpointId,
+            uint64(_commitDuration),
+            uint64(_revealDuration),
+            uint64(_startTime),
+            uint24(_totalProposals),
+            uint32(0),
+            true
+        ));
+        emit BallotCreated(_ballotId, _commitDuration, _revealDuration, _totalProposals, _startTime, _proposedQuorum, _checkpointId);
+    }
+
+    /**
+     * @notice Used to commit the vote
+     * @param _ballotId Given ballot Id
+     * @param _secretVote It is secret hash value (hashed offchain)
+     */
+    function commitVote(uint256 _ballotId, bytes32 _secretVote) external {
+        _validBallotId(_ballotId);
+        require(getCurrentBallotStage(_ballotId) == Stage.COMMIT, "Not in commit stage");
+        Ballot storage ballot = ballots[_ballotId];
+        require(ballot.proposalToVote[msg.sender].secretVote == bytes32(0), "Already voted");
+        require(_secretVote != bytes32(0), "Invalid vote");
+        require(ballot.isActive, "Inactive ballot");
+        uint256 weight = ISecurityToken(securityToken).balanceOfAt(msg.sender, ballot.checkpointId);
+        require(weight > 0, "Zero weight is not allowed");
+        ballot.proposalToVote[msg.sender] = Vote(0, _secretVote);
+        emit VoteCommit(msg.sender, weight, _ballotId, _secretVote);
+    }
+
+    /**
+     * @notice Used to reveal the vote
+     * @param _ballotId Given ballot Id
+     * @param _choiceOfProposal Proposal chossed by the voter. It varies from (0 to totalProposals - 1)
+     * @param _salt used salt for hashing (unique for each user)
+     */
+    function revealVote(uint256 _ballotId, uint256 _choiceOfProposal, uint256 _salt) external {
+        _validBallotId(_ballotId);
+        require(getCurrentBallotStage(_ballotId) == Stage.REVEAL, "Not in reveal stage");
+        Ballot storage ballot = ballots[_ballotId];
+        require(ballot.isActive, "Inactive ballot");
+        require(ballot.proposalToVote[msg.sender].secretVote != bytes32(0), "Secret vote not available");
+        require(_choiceOfProposal < ballot.totalProposals && _choiceOfProposal >= 1, "Invalid proposal choice");
+
+        // validate the secret vote
+        require(
+            bytes32(keccak256(abi.encodePacked(_choiceOfProposal, _salt))) == ballot.proposalToVote[msg.sender].secretVote,
+            "Invalid vote"
+        );
+        uint256 weight = ISecurityToken(securityToken).balanceOfAt(msg.sender, ballot.checkpointId);
+        bytes32 secretVote = ballot.proposalToVote[msg.sender].secretVote;
+        ballot.weightedVote[_choiceOfProposal] = ballot.weightedVote[_choiceOfProposal].add(weight);
+        ballot.totalVoters = ballot.totalVoters + 1;
+        ballot.proposalToVote[msg.sender].voteOption = _choiceOfProposal;
+        ballot.proposalToVote[msg.sender].secretVote = bytes32(0);
+        emit VoteRevealed(msg.sender, weight, _ballotId, _choiceOfProposal, _salt, secretVote);
+    }
+
+    /**
+     * @notice Allows the token issuer to set the active stats of a ballot
+     * @param _ballotId The index of the target ballot
+     * @param _isActive The bool value of the active stats of the ballot
+     */
+    function changeBallotStatus(uint256 _ballotId, bool _isActive) external withPerm(ADMIN) {
+        _validBallotId(_ballotId);
+        require(
+            now <= uint256(ballots[_ballotId].startTime)
+            .add(uint256(ballots[_ballotId].commitDuration)
+            .add(uint256(ballots[_ballotId].revealDuration))),
+            "Already ended"
+        );
+        require(ballots[_ballotId].isActive != _isActive, "Active state unchanged");
+        ballots[_ballotId].isActive = _isActive;
+        emit BallotStatusChanged(_ballotId, _isActive);
+    }
+
+    /**
+     * @notice Used to get the current stage of the ballot
+     * @param _ballotId Given ballot Id
+     */
+    function getCurrentBallotStage(uint256 _ballotId) public view returns (Stage) {
+        Ballot memory ballot = ballots[_ballotId];
+        uint256 commitTimeEnd = uint256(ballot.startTime).add(uint256(ballot.commitDuration));
+        uint256 revealTimeEnd = commitTimeEnd.add(uint256(ballot.revealDuration));
+
+        if (now < ballot.startTime)
+            return Stage.PREP;
+        else if (now <= commitTimeEnd && now >= ballot.startTime)
+            return Stage.COMMIT;
+        else if ( now > commitTimeEnd && now <= revealTimeEnd)
+            return Stage.REVEAL;
+        else if (now > revealTimeEnd)
+            return Stage.RESOLVED;
+    }
+
+    /**
+     * @notice Queries the result of a given ballot
+     * @param _ballotId Id of the target ballot
+     * @return uint256 voteWeighting
+     * @return uint256 tieWith
+     * @return uint256 winningProposal
+     * @return bool isVotingSucceed
+     * @return uint256 totalVoters
+     */
+    function getBallotResults(uint256 _ballotId) external view returns(uint256[] memory, uint256[] memory, uint256, bool, uint256) {
+        if (_ballotId >= ballots.length)
+            return (new uint256[](0), new uint256[](0), 0, false, 0);
+
+        Ballot storage ballot = ballots[_ballotId];
+        uint256 i = 0;
+        bool isVotingSucceed = false;
+        uint256 counter = 0;
+        uint256 maxWeight = 0;
+        uint256 winningProposal = 0;
+        uint256 supplyAtCheckpoint = ISecurityToken(securityToken).totalSupplyAt(ballot.checkpointId);
+        uint256 quorumWeight = (supplyAtCheckpoint.mul(ballot.quorum)).div(10 ** 18);
+        uint256[] memory voteWeighting = new uint256[](ballot.totalProposals);
+        for (i = 0; i < ballot.totalProposals; i++) {
+            voteWeighting[i] = ballot.weightedVote[i + 1];
+            if (maxWeight < ballot.weightedVote[i + 1]) {
+                maxWeight = ballot.weightedVote[i + 1];
+                if (maxWeight >= quorumWeight)
+                    winningProposal = i + 1;
+            }
+        }
+        if (maxWeight >= quorumWeight) {
+            isVotingSucceed = true;
+            for (i = 0; i < ballot.totalProposals; i++) {
+                if (maxWeight == ballot.weightedVote[i + 1] && (i + 1) != winningProposal)
+                    counter ++;
+            }
+        }
+
+        uint256[] memory tieWith = new uint256[](counter);
+        if (counter > 0) {
+            counter = 0;
+            for (i = 0; i < ballot.totalProposals; i++) {
+                if (maxWeight == ballot.weightedVote[i + 1] && (i + 1) != winningProposal) {
+                    tieWith[counter] = i + 1;
+                    counter ++;
+                }   
+            }
+        }
+        return (voteWeighting, tieWith, winningProposal, isVotingSucceed, ballot.totalVoters);  
+    }
+
+    /**
+     * @notice Get the voted proposal
+     * @param _ballotId Id of the ballot
+     * @param _voter Address of the voter
+     */
+    function getSelectedProposal(uint256 _ballotId, address _voter) external view returns(uint256 proposalId) {
+        if (_ballotId >= ballots.length)
+            return 0;
+        return (ballots[_ballotId].proposalToVote[_voter].voteOption);
+    }
+
+    /**
+     * @notice Get the stats of the ballot
+     * @param _ballotId The index of the target ballot
+     */
+    function getBallotStats(uint256 _ballotId) external view returns(uint256, uint256, uint256, uint64, uint64, uint64, uint32, uint32, bool) {
+        Ballot memory ballot = ballots[_ballotId];
+        return (
+            ballot.quorum,
+            ISecurityToken(securityToken).totalSupplyAt(ballot.checkpointId),
+            ballot.checkpointId,
+            ballot.commitDuration,
+            ballot.revealDuration,
+            ballot.startTime,
+            ballot.totalProposals,
+            ballot.totalVoters,
+            ballot.isActive
+        );
+    }
+
+    /**
+     * @notice This function returns the signature of configure function
+     */
+    function getInitFunction() external pure returns(bytes4) {
+        return bytes4(0);
+    }
+
+    /**
+     * @notice Return the permissions flag that are associated with CountTransferManager
+     */
+    function getPermissions() external view returns(bytes32[] memory) {
+        bytes32[] memory allPermissions = new bytes32[](1);
+        allPermissions[0] = ADMIN;
+        return allPermissions;
+    }
+
+    function _validValueCheck(uint256 _value) internal pure {
+        require(_value > 0, "Invalid value");
+    }
+
+    function _validBallotId(uint256 _ballotId) internal view {
+        require(ballots.length > _ballotId, "Index out of bound");
+    }
+}

contracts/modules/Experimental/Checkpoints/PLCRVotingCheckpointFactory.sol

@@ -0,0 +1,49 @@
+pragma solidity ^0.5.0;
+
+import "./PLCRVotingCheckpoint.sol";
+import "../../ModuleFactory.sol";
+
+/**
+ * @title Factory for deploying PLCRVotingCheckpoint module
+ */
+contract PLCRVotingCheckpointFactory is ModuleFactory {
+
+    /**
+     * @notice Constructor
+     * @param _setupCost Setup cost of the module
+     * @param _usageCost Usage cost of the module
+     * @param _polymathRegistry Address of the Polymath registry
+     * @param _isCostInPoly true = cost in Poly, false = USD
+     */
+    constructor (
+        uint256 _setupCost,
+        uint256 _usageCost,
+        address _polymathRegistry,
+        bool _isCostInPoly
+    ) 
+        public
+        ModuleFactory(_setupCost, _usageCost, _polymathRegistry, _isCostInPoly)
+    {
+        initialVersion = "3.0.0";
+        name = "PLCRVotingCheckpoint";
+        title = "PLCR Voting Checkpoint";
+        description = "Commit & reveal technique used for voting";
+        typesData.push(4);
+        tagsData.push("Vote");
+        tagsData.push("Checkpoint");
+        tagsData.push("PLCR");
+        compatibleSTVersionRange["lowerBound"] = VersionUtils.pack(uint8(3), uint8(0), uint8(0));
+        compatibleSTVersionRange["upperBound"] = VersionUtils.pack(uint8(3), uint8(0), uint8(0));
+
+    }
+
+    /**
+     * @notice used to launch the Module with the help of factory
+     * @return address Contract address of the Module
+     */
+    function deploy(bytes calldata _data) external returns(address) {
+        address plcrVotingCheckpoint = address(new PLCRVotingCheckpoint(msg.sender, IPolymathRegistry(polymathRegistry).getAddress("PolyToken")));
+        _initializeModule(plcrVotingCheckpoint, _data);
+        return plcrVotingCheckpoint;
+    }
+}