Permalink
Find file Copy path
Fetching contributors…
Cannot retrieve contributors at this time
353 lines (294 sloc) 12.7 KB
/*
* SPDX-License-Identitifer: GPL-3.0-or-later
*/
pragma solidity 0.4.24;
import "@aragon/os/contracts/apps/AragonApp.sol";
import "@aragon/os/contracts/common/IForwarder.sol";
import "@aragon/os/contracts/lib/math/SafeMath.sol";
import "@aragon/os/contracts/lib/math/SafeMath64.sol";
import "@aragon/apps-shared-minime/contracts/MiniMeToken.sol";
contract Voting is IForwarder, AragonApp {
using SafeMath for uint256;
using SafeMath64 for uint64;
bytes32 public constant CREATE_VOTES_ROLE = keccak256("CREATE_VOTES_ROLE");
bytes32 public constant MODIFY_SUPPORT_ROLE = keccak256("MODIFY_SUPPORT_ROLE");
bytes32 public constant MODIFY_QUORUM_ROLE = keccak256("MODIFY_QUORUM_ROLE");
uint64 public constant PCT_BASE = 10 ** 18; // 0% = 0; 1% = 10^16; 100% = 10^18
string private constant ERROR_NO_VOTE = "VOTING_NO_VOTE";
string private constant ERROR_INIT_PCTS = "VOTING_INIT_PCTS";
string private constant ERROR_CHANGE_SUPPORT_PCTS = "VOTING_CHANGE_SUPPORT_PCTS";
string private constant ERROR_CHANGE_QUORUM_PCTS = "VOTING_CHANGE_QUORUM_PCTS";
string private constant ERROR_INIT_SUPPORT_TOO_BIG = "VOTING_INIT_SUPPORT_TOO_BIG";
string private constant ERROR_CHANGE_SUPPORT_TOO_BIG = "VOTING_CHANGE_SUPP_TOO_BIG";
string private constant ERROR_CAN_NOT_VOTE = "VOTING_CAN_NOT_VOTE";
string private constant ERROR_CAN_NOT_EXECUTE = "VOTING_CAN_NOT_EXECUTE";
string private constant ERROR_CAN_NOT_FORWARD = "VOTING_CAN_NOT_FORWARD";
string private constant ERROR_NO_VOTING_POWER = "VOTING_NO_VOTING_POWER";
enum VoterState { Absent, Yea, Nay }
struct Vote {
bool executed;
uint64 startDate;
uint64 snapshotBlock;
uint64 supportRequiredPct;
uint64 minAcceptQuorumPct;
uint256 yea;
uint256 nay;
uint256 votingPower;
bytes executionScript;
mapping (address => VoterState) voters;
}
MiniMeToken public token;
uint64 public supportRequiredPct;
uint64 public minAcceptQuorumPct;
uint64 public voteTime;
// We are mimicing an array, we use a mapping instead to make app upgrade more graceful
mapping (uint256 => Vote) internal votes;
uint256 public votesLength;
event StartVote(uint256 indexed voteId, address indexed creator, string metadata);
event CastVote(uint256 indexed voteId, address indexed voter, bool supports, uint256 stake);
event ExecuteVote(uint256 indexed voteId);
event ChangeSupportRequired(uint64 supportRequiredPct);
event ChangeMinQuorum(uint64 minAcceptQuorumPct);
modifier voteExists(uint256 _voteId) {
require(_voteId < votesLength, ERROR_NO_VOTE);
_;
}
/**
* @notice Initialize Voting app with `_token.symbol(): string` for governance, minimum support of `@formatPct(_supportRequiredPct)`%, minimum acceptance quorum of `@formatPct(_minAcceptQuorumPct)`%, and a voting duration of `@transformTime(_voteTime)`
* @param _token MiniMeToken Address that will be used as governance token
* @param _supportRequiredPct Percentage of yeas in casted votes for a vote to succeed (expressed as a percentage of 10^18; eg. 10^16 = 1%, 10^18 = 100%)
* @param _minAcceptQuorumPct Percentage of yeas in total possible votes for a vote to succeed (expressed as a percentage of 10^18; eg. 10^16 = 1%, 10^18 = 100%)
* @param _voteTime Seconds that a vote will be open for token holders to vote (unless enough yeas or nays have been cast to make an early decision)
*/
function initialize(
MiniMeToken _token,
uint64 _supportRequiredPct,
uint64 _minAcceptQuorumPct,
uint64 _voteTime
)
external
onlyInit
{
initialized();
require(_minAcceptQuorumPct <= _supportRequiredPct, ERROR_INIT_PCTS);
require(_supportRequiredPct < PCT_BASE, ERROR_INIT_SUPPORT_TOO_BIG);
token = _token;
supportRequiredPct = _supportRequiredPct;
minAcceptQuorumPct = _minAcceptQuorumPct;
voteTime = _voteTime;
}
/**
* @notice Change required support to `@formatPct(_supportRequiredPct)`%
* @param _supportRequiredPct New required support
*/
function changeSupportRequiredPct(uint64 _supportRequiredPct)
external
authP(MODIFY_SUPPORT_ROLE, arr(uint256(_supportRequiredPct), uint256(supportRequiredPct)))
{
require(minAcceptQuorumPct <= _supportRequiredPct, ERROR_CHANGE_SUPPORT_PCTS);
require(_supportRequiredPct < PCT_BASE, ERROR_CHANGE_SUPPORT_TOO_BIG);
supportRequiredPct = _supportRequiredPct;
emit ChangeSupportRequired(_supportRequiredPct);
}
/**
* @notice Change minimum acceptance quorum to `@formatPct(_minAcceptQuorumPct)`%
* @param _minAcceptQuorumPct New acceptance quorum
*/
function changeMinAcceptQuorumPct(uint64 _minAcceptQuorumPct)
external
authP(MODIFY_QUORUM_ROLE, arr(uint256(_minAcceptQuorumPct), uint256(minAcceptQuorumPct)))
{
require(_minAcceptQuorumPct <= supportRequiredPct, ERROR_CHANGE_QUORUM_PCTS);
minAcceptQuorumPct = _minAcceptQuorumPct;
emit ChangeMinQuorum(_minAcceptQuorumPct);
}
/**
* @notice Create a new vote about "`_metadata`"
* @param _executionScript EVM script to be executed on approval
* @param _metadata Vote metadata
* @return voteId Id for newly created vote
*/
function newVote(bytes _executionScript, string _metadata) external auth(CREATE_VOTES_ROLE) returns (uint256 voteId) {
return _newVote(_executionScript, _metadata, true, true);
}
/**
* @notice Create a new vote about "`_metadata`"
* @param _executionScript EVM script to be executed on approval
* @param _metadata Vote metadata
* @param _castVote Whether to also cast newly created vote
* @param _executesIfDecided Whether to also immediately execute newly created vote if decided
* @return voteId id for newly created vote
*/
function newVote(bytes _executionScript, string _metadata, bool _castVote, bool _executesIfDecided)
external
auth(CREATE_VOTES_ROLE)
returns (uint256 voteId)
{
return _newVote(_executionScript, _metadata, _castVote, _executesIfDecided);
}
/**
* @notice Vote `_supports ? 'yes' : 'no'` in vote #`_voteId`
* @dev Initialization check is implicitly provided by `voteExists()` as new votes can only be
* created via `newVote(),` which requires initialization
* @param _voteId Id for vote
* @param _supports Whether voter supports the vote
* @param _executesIfDecided Whether the vote should execute its action if it becomes decided
*/
function vote(uint256 _voteId, bool _supports, bool _executesIfDecided) external voteExists(_voteId) {
require(canVote(_voteId, msg.sender), ERROR_CAN_NOT_VOTE);
_vote(_voteId, _supports, msg.sender, _executesIfDecided);
}
/**
* @notice Execute vote #`_voteId`
* @dev Initialization check is implicitly provided by `voteExists()` as new votes can only be
* created via `newVote(),` which requires initialization
* @param _voteId Id for vote
*/
function executeVote(uint256 _voteId) external voteExists(_voteId) {
require(canExecute(_voteId), ERROR_CAN_NOT_EXECUTE);
_executeVote(_voteId);
}
function isForwarder() public pure returns (bool) {
return true;
}
/**
* @notice Creates a vote to execute the desired action, and casts a support vote if possible
* @dev IForwarder interface conformance
* @param _evmScript Start vote with script
*/
function forward(bytes _evmScript) public {
require(canForward(msg.sender, _evmScript), ERROR_CAN_NOT_FORWARD);
_newVote(_evmScript, "", true, true);
}
function canForward(address _sender, bytes) public view returns (bool) {
// Note that `canPerform()` implicitly does an initialization check itself
return canPerform(_sender, CREATE_VOTES_ROLE, arr());
}
function canVote(uint256 _voteId, address _voter) public view voteExists(_voteId) returns (bool) {
Vote storage vote_ = votes[_voteId];
return _isVoteOpen(vote_) && token.balanceOfAt(_voter, vote_.snapshotBlock) > 0;
}
function canExecute(uint256 _voteId) public view voteExists(_voteId) returns (bool) {
Vote storage vote_ = votes[_voteId];
if (vote_.executed) {
return false;
}
// Voting is already decided
if (_isValuePct(vote_.yea, vote_.votingPower, vote_.supportRequiredPct)) {
return true;
}
uint256 totalVotes = vote_.yea.add(vote_.nay);
// Vote ended?
if (_isVoteOpen(vote_)) {
return false;
}
// Has enough support?
if (!_isValuePct(vote_.yea, totalVotes, vote_.supportRequiredPct)) {
return false;
}
// Has min quorum?
if (!_isValuePct(vote_.yea, vote_.votingPower, vote_.minAcceptQuorumPct)) {
return false;
}
return true;
}
function getVote(uint256 _voteId)
public
view
voteExists(_voteId)
returns (
bool open,
bool executed,
uint64 startDate,
uint64 snapshotBlock,
uint64 supportRequired,
uint64 minAcceptQuorum,
uint256 yea,
uint256 nay,
uint256 votingPower,
bytes script
)
{
Vote storage vote_ = votes[_voteId];
open = _isVoteOpen(vote_);
executed = vote_.executed;
startDate = vote_.startDate;
snapshotBlock = vote_.snapshotBlock;
supportRequired = vote_.supportRequiredPct;
minAcceptQuorum = vote_.minAcceptQuorumPct;
yea = vote_.yea;
nay = vote_.nay;
votingPower = vote_.votingPower;
script = vote_.executionScript;
}
function getVoterState(uint256 _voteId, address _voter) public view voteExists(_voteId) returns (VoterState) {
return votes[_voteId].voters[_voter];
}
function _newVote(bytes _executionScript, string _metadata, bool _castVote, bool _executesIfDecided)
internal
returns (uint256 voteId)
{
uint256 votingPower = token.totalSupplyAt(vote_.snapshotBlock);
require(votingPower > 0, ERROR_NO_VOTING_POWER);
voteId = votesLength++;
Vote storage vote_ = votes[voteId];
vote_.startDate = getTimestamp64();
vote_.snapshotBlock = getBlockNumber64() - 1; // avoid double voting in this very block
vote_.supportRequiredPct = supportRequiredPct;
vote_.minAcceptQuorumPct = minAcceptQuorumPct;
vote_.votingPower = votingPower;
vote_.executionScript = _executionScript;
emit StartVote(voteId, msg.sender, _metadata);
if (_castVote && canVote(voteId, msg.sender)) {
_vote(voteId, true, msg.sender, _executesIfDecided);
}
}
function _vote(
uint256 _voteId,
bool _supports,
address _voter,
bool _executesIfDecided
) internal
{
Vote storage vote_ = votes[_voteId];
// This could re-enter, though we can assume the governance token is not malicious
uint256 voterStake = token.balanceOfAt(_voter, vote_.snapshotBlock);
VoterState state = vote_.voters[_voter];
// If voter had previously voted, decrease count
if (state == VoterState.Yea) {
vote_.yea = vote_.yea.sub(voterStake);
} else if (state == VoterState.Nay) {
vote_.nay = vote_.nay.sub(voterStake);
}
if (_supports) {
vote_.yea = vote_.yea.add(voterStake);
} else {
vote_.nay = vote_.nay.add(voterStake);
}
vote_.voters[_voter] = _supports ? VoterState.Yea : VoterState.Nay;
emit CastVote(_voteId, _voter, _supports, voterStake);
if (_executesIfDecided && canExecute(_voteId)) {
_executeVote(_voteId);
}
}
function _executeVote(uint256 _voteId) internal {
Vote storage vote_ = votes[_voteId];
vote_.executed = true;
bytes memory input = new bytes(0); // TODO: Consider input for voting scripts
runScript(vote_.executionScript, input, new address[](0));
emit ExecuteVote(_voteId);
}
function _isVoteOpen(Vote storage vote_) internal view returns (bool) {
return getTimestamp64() < vote_.startDate.add(voteTime) && !vote_.executed;
}
/**
* @dev Calculates whether `_value` is more than a percentage `_pct` of `_total`
*/
function _isValuePct(uint256 _value, uint256 _total, uint256 _pct) internal pure returns (bool) {
if (_total == 0) {
return false;
}
uint256 computedPct = _value.mul(PCT_BASE) / _total;
return computedPct > _pct;
}
}