Contract Address Details

/*
 * 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/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");
    bytes32 public constant UNSAFELY_MODIFY_VOTE_TIME_ROLE = keccak256("UNSAFELY_MODIFY_VOTE_TIME_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";
    string private constant ERROR_CHANGE_VOTE_TIME = "VOTING_VOTE_TIME_TOO_SMALL";
    string private constant ERROR_CHANGE_OBJECTION_TIME = "VOTING_OBJ_TIME_TOO_BIG";
    string private constant ERROR_INIT_OBJ_TIME_TOO_BIG = "VOTING_INIT_OBJ_TIME_TOO_BIG";

    enum VoterState { Absent, Yea, Nay }

    enum VotePhase { Main, Objection, Closed }

    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;
    uint64 public objectionPhaseTime;

    event StartVote(uint256 indexed voteId, address indexed creator, string metadata);
    event CastVote(uint256 indexed voteId, address indexed voter, bool supports, uint256 stake);
    event CastObjection(uint256 indexed voteId, address indexed voter, uint256 stake);
    event ExecuteVote(uint256 indexed voteId);
    event ChangeSupportRequired(uint64 supportRequiredPct);
    event ChangeMinQuorum(uint64 minAcceptQuorumPct);
    event ChangeVoteTime(uint64 voteTime);
    event ChangeObjectionPhaseTime(uint64 objectionPhaseTime);

    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 Total duration of voting in seconds.
    * @param _objectionPhaseTime The duration of the objection vote phase, i.e. seconds that a vote will be open after the main vote phase ends for token holders to object to the outcome. Main phase duration is calculated as `voteTime - objectionPhaseTime`.
    */
    function initialize(MiniMeToken _token, uint64 _supportRequiredPct, uint64 _minAcceptQuorumPct, uint64 _voteTime, uint64 _objectionPhaseTime)
        external
        onlyInit
    {
        initialized();

        require(_minAcceptQuorumPct <= _supportRequiredPct, ERROR_INIT_PCTS);
        require(_supportRequiredPct < PCT_BASE, ERROR_INIT_SUPPORT_TOO_BIG);
        require(_voteTime > _objectionPhaseTime, ERROR_INIT_OBJ_TIME_TOO_BIG);

        token = _token;
        supportRequiredPct = _supportRequiredPct;
        minAcceptQuorumPct = _minAcceptQuorumPct;
        voteTime = _voteTime;
        objectionPhaseTime = _objectionPhaseTime;
    }

    /**
    * @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 Change vote time to `_voteTime` sec. The change affects all existing unexecuted votes, so be really careful with it
    * @param _voteTime New vote time
    */
    function unsafelyChangeVoteTime(uint64 _voteTime)
        external
        auth(UNSAFELY_MODIFY_VOTE_TIME_ROLE)
    {
        require(_voteTime > objectionPhaseTime, ERROR_CHANGE_VOTE_TIME);
        voteTime = _voteTime;

        emit ChangeVoteTime(_voteTime);
    }

    /**
    * @notice Change the objection phase duration to `_objectionPhaseTime` sec. The change affects all existing unexecuted votes, so be really careful with it
    * @param _objectionPhaseTime New objection time
    */
    function unsafelyChangeObjectionPhaseTime(uint64 _objectionPhaseTime)
        external
        auth(UNSAFELY_MODIFY_VOTE_TIME_ROLE)
    {
        require(voteTime > _objectionPhaseTime, ERROR_CHANGE_OBJECTION_TIME);
        objectionPhaseTime = _objectionPhaseTime;

        emit ChangeObjectionPhaseTime(_objectionPhaseTime);
    }

    /**
    * @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);
    }

    /**
    * @notice Create a new vote about "`_metadata`"
    * @dev  _executesIfDecided was deprecated to introduce a proper lock period between decision and execution.
    * @param _executionScript EVM script to be executed on approval
    * @param _metadata Vote metadata
    * @param _castVote Whether to also cast newly created vote
    * @param _executesIfDecided_deprecated 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_deprecated)
        external
        auth(CREATE_VOTES_ROLE)
        returns (uint256 voteId)
    {
        return _newVote(_executionScript, _metadata, _castVote);
    }

    /**
    * @notice Vote `_supports ? 'yes' : 'no'` in vote #`_voteId`. During objection phase one can only vote 'no'
    * @dev Initialization check is implicitly provided by `voteExists()` as new votes can only be
    *      created via `newVote(),` which requires initialization
    * @dev  _executesIfDecided was deprecated to introduce a proper lock period between decision and execution.
    * @param _voteId Id for vote
    * @param _supports Whether voter supports the vote
    * @param _executesIfDecided_deprecated Whether the vote should execute its action if it becomes decided
    */
    function vote(uint256 _voteId, bool _supports, bool _executesIfDecided_deprecated) external voteExists(_voteId) {
        require(_canVote(_voteId, msg.sender), ERROR_CAN_NOT_VOTE);
        require(!_supports || _getVotePhase(votes[_voteId]) == VotePhase.Main, ERROR_CAN_NOT_VOTE);
        _vote(_voteId, _supports, msg.sender);
    }

    /**
    * @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) {
        _executeVote(_voteId);
    }

    // Forwarding fns

    /**
    * @notice Tells whether the Voting app is a forwarder or not
    * @dev IForwarder interface conformance
    * @return Always true
    */
    function isForwarder() external 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);
    }

    /**
    * @notice Tells whether `_sender` can forward actions or not
    * @dev IForwarder interface conformance
    * @param _sender Address of the account intending to forward an action
    * @return True if the given address can create votes, false otherwise
    */
    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());
    }

    // Getter fns

    /**
    * @notice Tells whether a vote #`_voteId` can be executed or not
    * @dev Initialization check is implicitly provided by `voteExists()` as new votes can only be
    *      created via `newVote(),` which requires initialization
    * @param _voteId Vote identifier
    * @return True if the given vote can be executed, false otherwise
    */
    function canExecute(uint256 _voteId) public view voteExists(_voteId) returns (bool) {
        return _canExecute(_voteId);
    }

    /**
    * @notice Tells whether `_voter` can participate in the main or objection phase of the vote #`_voteId`
    * @dev Initialization check is implicitly provided by `voteExists()` as new votes can only be
    *      created via `newVote(),` which requires initialization
    * @param _voteId Vote identifier
    * @param _voter address of the voter to check
    * @return True if the given voter can participate in the main phase of a certain vote, false otherwise
    */
    function canVote(uint256 _voteId, address _voter) external view voteExists(_voteId) returns (bool) {
        return _canVote(_voteId, _voter);
    }

    /**
    * @notice Tells the current phase of the vote #`_voteId`
    * @dev Initialization check is implicitly provided by `voteExists()` as new votes can only be
    *      created via `newVote(),` which requires initialization
    * @param _voteId Vote identifier
    * @return VotePhase.Main if one can vote yes or no and VotePhase.Objection if one can vote only no and VotingPhase.Closed if no votes are accepted
    */
    function getVotePhase(uint256 _voteId) external view voteExists(_voteId) returns (VotePhase) {
        return _getVotePhase(votes[_voteId]);
    }

    /**
    * @dev Return all information for a vote by its ID
    * @param _voteId Vote identifier
    * @return true if the vote is open
    * @return Vote executed status
    * @return Vote start date
    * @return Vote snapshot block
    * @return Vote support required
    * @return Vote minimum acceptance quorum
    * @return Vote yeas amount
    * @return Vote nays amount
    * @return Vote power
    * @return Vote script
    * @return Vote phase
    */
    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,
            VotePhase phase
        )
    {
        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;
        phase = _getVotePhase(vote_);
    }

    /**
    * @dev Return the state of a voter for a given vote by its ID
    * @param _voteId Vote identifier
    * @param _voter address of the voter
    * @return VoterState of the requested voter for a certain vote
    */
    function getVoterState(uint256 _voteId, address _voter) public view voteExists(_voteId) returns (VoterState) {
        return votes[_voteId].voters[_voter];
    }

    // Internal fns

    /**
    * @dev Internal function to create a new vote
    * @return voteId id for newly created vote
    */
    function _newVote(bytes _executionScript, string _metadata, bool _castVote) internal returns (uint256 voteId) {
        uint64 snapshotBlock = getBlockNumber64() - 1; // avoid double voting in this very block
        uint256 votingPower = token.totalSupplyAt(snapshotBlock);
        require(votingPower > 0, ERROR_NO_VOTING_POWER);

        voteId = votesLength++;

        Vote storage vote_ = votes[voteId];
        vote_.startDate = getTimestamp64();
        vote_.snapshotBlock = snapshotBlock;
        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);
        }
    }

    /**
    * @dev Internal function to cast a vote or object to.
      @dev It assumes that voter can support or object to the vote
    */
    function _vote(uint256 _voteId, bool _supports, address _voter) 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);
            vote_.voters[_voter] = VoterState.Yea;
        } else {
            vote_.nay = vote_.nay.add(voterStake);
            vote_.voters[_voter] = VoterState.Nay;
        }

        emit CastVote(_voteId, _voter, _supports, voterStake);

        if (_getVotePhase(vote_) == VotePhase.Objection) {
            emit CastObjection(_voteId, _voter, voterStake);
        }
    }

    /**
    * @dev Internal function to execute a vote. It assumes the queried vote exists.
    */
    function _executeVote(uint256 _voteId) internal {
        require(_canExecute(_voteId), ERROR_CAN_NOT_EXECUTE);
        _unsafeExecuteVote(_voteId);
    }

    /**
    * @dev Unsafe version of _executeVote that assumes you have already checked if the vote can be executed and exists
    */
    function _unsafeExecuteVote(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);
    }

    /**
    * @dev Internal function to check if a vote can be executed. It assumes the queried vote exists.
    * @return True if the given vote can be executed, false otherwise
    */
    function _canExecute(uint256 _voteId) internal view returns (bool) {
        Vote storage vote_ = votes[_voteId];

        if (vote_.executed) {
            return false;
        }

        // Vote ended?
        if (_isVoteOpen(vote_)) {
            return false;
        }

        // Has enough support?
        uint256 voteYea = vote_.yea;
        uint256 totalVotes = voteYea.add(vote_.nay);
        if (!_isValuePct(voteYea, totalVotes, vote_.supportRequiredPct)) {
            return false;
        }
        // Has min quorum?
        if (!_isValuePct(voteYea, vote_.votingPower, vote_.minAcceptQuorumPct)) {
            return false;
        }

        return true;
    }

    /**
    * @dev Internal function to check if a voter can participate on a vote. It assumes the queried vote exists.
    * @return True if the given voter can participate a certain vote, false otherwise
    */
    function _canVote(uint256 _voteId, address _voter) internal view returns (bool) {
        Vote storage vote_ = votes[_voteId];
        return _isVoteOpen(vote_) && token.balanceOfAt(_voter, vote_.snapshotBlock) > 0;
    }

    /**
    * @dev Internal function to get the current phase of the vote. It assumes the queried vote exists.
    * @return VotePhase.Main if one can vote 'yes' or 'no', VotePhase.Objection if one can vote only 'no' or VotePhase.Closed if no votes are accepted
    */
    function _getVotePhase(Vote storage vote_) internal view returns (VotePhase) {
        uint64 timestamp = getTimestamp64();
        uint64 voteTimeEnd = vote_.startDate.add(voteTime);
        if (timestamp < voteTimeEnd.sub(objectionPhaseTime)) {
            return VotePhase.Main;
        }
        if (timestamp < voteTimeEnd) {
            return VotePhase.Objection;
        }
        return VotePhase.Closed;
    }

    /**
    * @dev Internal function to check if a vote is still open for both support and objection
    * @return True if less than voteTime has passed since the vote start
    */
    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;
    }
}
        

/*
 * SPDX-License-Identifier:    MIT
 */

pragma solidity ^0.4.24;


interface IForwarder {
    function isForwarder() external pure returns (bool);

    // TODO: this should be external
    // See https://github.com/ethereum/solidity/issues/4832
    function canForward(address sender, bytes evmCallScript) public view returns (bool);

    // TODO: this should be external
    // See https://github.com/ethereum/solidity/issues/4832
    function forward(bytes evmCallScript) public;
}
          

/*
 * SPDX-License-Identifier:    MIT
 */

pragma solidity ^0.4.24;


interface IVaultRecoverable {
    event RecoverToVault(address indexed vault, address indexed token, uint256 amount);

    function transferToVault(address token) external;

    function allowRecoverability(address token) external view returns (bool);
    function getRecoveryVault() external view returns (address);
}
          

/*
 * SPDX-License-Identifier:    MIT
 */

pragma solidity ^0.4.24;

import "./Petrifiable.sol";


contract Autopetrified is Petrifiable {
    constructor() public {
        // Immediately petrify base (non-proxy) instances of inherited contracts on deploy.
        // This renders them uninitializable (and unusable without a proxy).
        petrify();
    }
}
          

pragma solidity ^0.4.24;


library ConversionHelpers {
    string private constant ERROR_IMPROPER_LENGTH = "CONVERSION_IMPROPER_LENGTH";

    function dangerouslyCastUintArrayToBytes(uint256[] memory _input) internal pure returns (bytes memory output) {
        // Force cast the uint256[] into a bytes array, by overwriting its length
        // Note that the bytes array doesn't need to be initialized as we immediately overwrite it
        // with the input and a new length. The input becomes invalid from this point forward.
        uint256 byteLength = _input.length * 32;
        assembly {
            output := _input
            mstore(output, byteLength)
        }
    }

    function dangerouslyCastBytesToUintArray(bytes memory _input) internal pure returns (uint256[] memory output) {
        // Force cast the bytes array into a uint256[], by overwriting its length
        // Note that the uint256[] doesn't need to be initialized as we immediately overwrite it
        // with the input and a new length. The input becomes invalid from this point forward.
        uint256 intsLength = _input.length / 32;
        require(_input.length == intsLength * 32, ERROR_IMPROPER_LENGTH);

        assembly {
            output := _input
            mstore(output, intsLength)
        }
    }
}
          

/*
 * SPDX-License-Identifier:    MIT
 */

pragma solidity ^0.4.24;


// aragonOS and aragon-apps rely on address(0) to denote native ETH, in
// contracts where both tokens and ETH are accepted
contract EtherTokenConstant {
    address internal constant ETH = address(0);
}
          

pragma solidity ^0.4.24;

/// @dev The token controller contract must implement these functions


interface ITokenController {
    /// @notice Called when `_owner` sends ether to the MiniMe Token contract
    /// @param _owner The address that sent the ether to create tokens
    /// @return True if the ether is accepted, false if it throws
    function proxyPayment(address _owner) external payable returns(bool);

    /// @notice Notifies the controller about a token transfer allowing the
    ///  controller to react if desired
    /// @param _from The origin of the transfer
    /// @param _to The destination of the transfer
    /// @param _amount The amount of the transfer
    /// @return False if the controller does not authorize the transfer
    function onTransfer(address _from, address _to, uint _amount) external returns(bool);

    /// @notice Notifies the controller about an approval allowing the
    ///  controller to react if desired
    /// @param _owner The address that calls `approve()`
    /// @param _spender The spender in the `approve()` call
    /// @param _amount The amount in the `approve()` call
    /// @return False if the controller does not authorize the approval
    function onApprove(address _owner, address _spender, uint _amount) external returns(bool);
}
          

pragma solidity ^0.4.24;

/*
    Copyright 2016, Jordi Baylina
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/// @title MiniMeToken Contract
/// @author Jordi Baylina
/// @dev This token contract's goal is to make it easy for anyone to clone this
///  token using the token distribution at a given block, this will allow DAO's
///  and DApps to upgrade their features in a decentralized manner without
///  affecting the original token
/// @dev It is ERC20 compliant, but still needs to under go further testing.

import "./ITokenController.sol";

contract Controlled {
    /// @notice The address of the controller is the only address that can call
    ///  a function with this modifier
    modifier onlyController {
        require(msg.sender == controller);
        _;
    }

    address public controller;

    function Controlled()  public { controller = msg.sender;}

    /// @notice Changes the controller of the contract
    /// @param _newController The new controller of the contract
    function changeController(address _newController) onlyController  public {
        controller = _newController;
    }
}

contract ApproveAndCallFallBack {
    function receiveApproval(
        address from,
        uint256 _amount,
        address _token,
        bytes _data
    ) public;
}

/// @dev The actual token contract, the default controller is the msg.sender
///  that deploys the contract, so usually this token will be deployed by a
///  token controller contract, which Giveth will call a "Campaign"
contract MiniMeToken is Controlled {

    string public name;                //The Token's name: e.g. DigixDAO Tokens
    uint8 public decimals;             //Number of decimals of the smallest unit
    string public symbol;              //An identifier: e.g. REP
    string public version = "MMT_0.1"; //An arbitrary versioning scheme


    /// @dev `Checkpoint` is the structure that attaches a block number to a
    ///  given value, the block number attached is the one that last changed the
    ///  value
    struct Checkpoint {

        // `fromBlock` is the block number that the value was generated from
        uint128 fromBlock;

        // `value` is the amount of tokens at a specific block number
        uint128 value;
    }

    // `parentToken` is the Token address that was cloned to produce this token;
    //  it will be 0x0 for a token that was not cloned
    MiniMeToken public parentToken;

    // `parentSnapShotBlock` is the block number from the Parent Token that was
    //  used to determine the initial distribution of the Clone Token
    uint public parentSnapShotBlock;

    // `creationBlock` is the block number that the Clone Token was created
    uint public creationBlock;

    // `balances` is the map that tracks the balance of each address, in this
    //  contract when the balance changes the block number that the change
    //  occurred is also included in the map
    mapping (address => Checkpoint[]) balances;

    // `allowed` tracks any extra transfer rights as in all ERC20 tokens
    mapping (address => mapping (address => uint256)) allowed;

    // Tracks the history of the `totalSupply` of the token
    Checkpoint[] totalSupplyHistory;

    // Flag that determines if the token is transferable or not.
    bool public transfersEnabled;

    // The factory used to create new clone tokens
    MiniMeTokenFactory public tokenFactory;

////////////////
// Constructor
////////////////

    /// @notice Constructor to create a MiniMeToken
    /// @param _tokenFactory The address of the MiniMeTokenFactory contract that
    ///  will create the Clone token contracts, the token factory needs to be
    ///  deployed first
    /// @param _parentToken Address of the parent token, set to 0x0 if it is a
    ///  new token
    /// @param _parentSnapShotBlock Block of the parent token that will
    ///  determine the initial distribution of the clone token, set to 0 if it
    ///  is a new token
    /// @param _tokenName Name of the new token
    /// @param _decimalUnits Number of decimals of the new token
    /// @param _tokenSymbol Token Symbol for the new token
    /// @param _transfersEnabled If true, tokens will be able to be transferred
    function MiniMeToken(
        MiniMeTokenFactory _tokenFactory,
        MiniMeToken _parentToken,
        uint _parentSnapShotBlock,
        string _tokenName,
        uint8 _decimalUnits,
        string _tokenSymbol,
        bool _transfersEnabled
    )  public
    {
        tokenFactory = _tokenFactory;
        name = _tokenName;                                 // Set the name
        decimals = _decimalUnits;                          // Set the decimals
        symbol = _tokenSymbol;                             // Set the symbol
        parentToken = _parentToken;
        parentSnapShotBlock = _parentSnapShotBlock;
        transfersEnabled = _transfersEnabled;
        creationBlock = block.number;
    }


///////////////////
// ERC20 Methods
///////////////////

    /// @notice Send `_amount` tokens to `_to` from `msg.sender`
    /// @param _to The address of the recipient
    /// @param _amount The amount of tokens to be transferred
    /// @return Whether the transfer was successful or not
    function transfer(address _to, uint256 _amount) public returns (bool success) {
        require(transfersEnabled);
        return doTransfer(msg.sender, _to, _amount);
    }

    /// @notice Send `_amount` tokens to `_to` from `_from` on the condition it
    ///  is approved by `_from`
    /// @param _from The address holding the tokens being transferred
    /// @param _to The address of the recipient
    /// @param _amount The amount of tokens to be transferred
    /// @return True if the transfer was successful
    function transferFrom(address _from, address _to, uint256 _amount) public returns (bool success) {

        // The controller of this contract can move tokens around at will,
        //  this is important to recognize! Confirm that you trust the
        //  controller of this contract, which in most situations should be
        //  another open source smart contract or 0x0
        if (msg.sender != controller) {
            require(transfersEnabled);

            // The standard ERC 20 transferFrom functionality
            if (allowed[_from][msg.sender] < _amount)
                return false;
            allowed[_from][msg.sender] -= _amount;
        }
        return doTransfer(_from, _to, _amount);
    }

    /// @dev This is the actual transfer function in the token contract, it can
    ///  only be called by other functions in this contract.
    /// @param _from The address holding the tokens being transferred
    /// @param _to The address of the recipient
    /// @param _amount The amount of tokens to be transferred
    /// @return True if the transfer was successful
    function doTransfer(address _from, address _to, uint _amount) internal returns(bool) {
        if (_amount == 0) {
            return true;
        }
        require(parentSnapShotBlock < block.number);
        // Do not allow transfer to 0x0 or the token contract itself
        require((_to != 0) && (_to != address(this)));
        // If the amount being transfered is more than the balance of the
        //  account the transfer returns false
        var previousBalanceFrom = balanceOfAt(_from, block.number);
        if (previousBalanceFrom < _amount) {
            return false;
        }
        // Alerts the token controller of the transfer
        if (isContract(controller)) {
            // Adding the ` == true` makes the linter shut up so...
            require(ITokenController(controller).onTransfer(_from, _to, _amount) == true);
        }
        // First update the balance array with the new value for the address
        //  sending the tokens
        updateValueAtNow(balances[_from], previousBalanceFrom - _amount);
        // Then update the balance array with the new value for the address
        //  receiving the tokens
        var previousBalanceTo = balanceOfAt(_to, block.number);
        require(previousBalanceTo + _amount >= previousBalanceTo); // Check for overflow
        updateValueAtNow(balances[_to], previousBalanceTo + _amount);
        // An event to make the transfer easy to find on the blockchain
        Transfer(_from, _to, _amount);
        return true;
    }

    /// @param _owner The address that's balance is being requested
    /// @return The balance of `_owner` at the current block
    function balanceOf(address _owner) public constant returns (uint256 balance) {
        return balanceOfAt(_owner, block.number);
    }

    /// @notice `msg.sender` approves `_spender` to spend `_amount` tokens on
    ///  its behalf. This is a modified version of the ERC20 approve function
    ///  to be a little bit safer
    /// @param _spender The address of the account able to transfer the tokens
    /// @param _amount The amount of tokens to be approved for transfer
    /// @return True if the approval was successful
    function approve(address _spender, uint256 _amount) public returns (bool success) {
        require(transfersEnabled);

        // To change the approve amount you first have to reduce the addresses`
        //  allowance to zero by calling `approve(_spender,0)` if it is not
        //  already 0 to mitigate the race condition described here:
        //  https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
        require((_amount == 0) || (allowed[msg.sender][_spender] == 0));

        // Alerts the token controller of the approve function call
        if (isContract(controller)) {
            // Adding the ` == true` makes the linter shut up so...
            require(ITokenController(controller).onApprove(msg.sender, _spender, _amount) == true);
        }

        allowed[msg.sender][_spender] = _amount;
        Approval(msg.sender, _spender, _amount);
        return true;
    }

    /// @dev This function makes it easy to read the `allowed[]` map
    /// @param _owner The address of the account that owns the token
    /// @param _spender The address of the account able to transfer the tokens
    /// @return Amount of remaining tokens of _owner that _spender is allowed
    ///  to spend
    function allowance(address _owner, address _spender) public constant returns (uint256 remaining) {
        return allowed[_owner][_spender];
    }

    /// @notice `msg.sender` approves `_spender` to send `_amount` tokens on
    ///  its behalf, and then a function is triggered in the contract that is
    ///  being approved, `_spender`. This allows users to use their tokens to
    ///  interact with contracts in one function call instead of two
    /// @param _spender The address of the contract able to transfer the tokens
    /// @param _amount The amount of tokens to be approved for transfer
    /// @return True if the function call was successful
    function approveAndCall(ApproveAndCallFallBack _spender, uint256 _amount, bytes _extraData) public returns (bool success) {
        require(approve(_spender, _amount));

        _spender.receiveApproval(
            msg.sender,
            _amount,
            this,
            _extraData
        );

        return true;
    }

    /// @dev This function makes it easy to get the total number of tokens
    /// @return The total number of tokens
    function totalSupply() public constant returns (uint) {
        return totalSupplyAt(block.number);
    }


////////////////
// Query balance and totalSupply in History
////////////////

    /// @dev Queries the balance of `_owner` at a specific `_blockNumber`
    /// @param _owner The address from which the balance will be retrieved
    /// @param _blockNumber The block number when the balance is queried
    /// @return The balance at `_blockNumber`
    function balanceOfAt(address _owner, uint _blockNumber) public constant returns (uint) {

        // These next few lines are used when the balance of the token is
        //  requested before a check point was ever created for this token, it
        //  requires that the `parentToken.balanceOfAt` be queried at the
        //  genesis block for that token as this contains initial balance of
        //  this token
        if ((balances[_owner].length == 0) || (balances[_owner][0].fromBlock > _blockNumber)) {
            if (address(parentToken) != 0) {
                return parentToken.balanceOfAt(_owner, min(_blockNumber, parentSnapShotBlock));
            } else {
                // Has no parent
                return 0;
            }

        // This will return the expected balance during normal situations
        } else {
            return getValueAt(balances[_owner], _blockNumber);
        }
    }

    /// @notice Total amount of tokens at a specific `_blockNumber`.
    /// @param _blockNumber The block number when the totalSupply is queried
    /// @return The total amount of tokens at `_blockNumber`
    function totalSupplyAt(uint _blockNumber) public constant returns(uint) {

        // These next few lines are used when the totalSupply of the token is
        //  requested before a check point was ever created for this token, it
        //  requires that the `parentToken.totalSupplyAt` be queried at the
        //  genesis block for this token as that contains totalSupply of this
        //  token at this block number.
        if ((totalSupplyHistory.length == 0) || (totalSupplyHistory[0].fromBlock > _blockNumber)) {
            if (address(parentToken) != 0) {
                return parentToken.totalSupplyAt(min(_blockNumber, parentSnapShotBlock));
            } else {
                return 0;
            }

        // This will return the expected totalSupply during normal situations
        } else {
            return getValueAt(totalSupplyHistory, _blockNumber);
        }
    }

////////////////
// Clone Token Method
////////////////

    /// @notice Creates a new clone token with the initial distribution being
    ///  this token at `_snapshotBlock`
    /// @param _cloneTokenName Name of the clone token
    /// @param _cloneDecimalUnits Number of decimals of the smallest unit
    /// @param _cloneTokenSymbol Symbol of the clone token
    /// @param _snapshotBlock Block when the distribution of the parent token is
    ///  copied to set the initial distribution of the new clone token;
    ///  if the block is zero than the actual block, the current block is used
    /// @param _transfersEnabled True if transfers are allowed in the clone
    /// @return The address of the new MiniMeToken Contract
    function createCloneToken(
        string _cloneTokenName,
        uint8 _cloneDecimalUnits,
        string _cloneTokenSymbol,
        uint _snapshotBlock,
        bool _transfersEnabled
    ) public returns(MiniMeToken)
    {
        uint256 snapshot = _snapshotBlock == 0 ? block.number - 1 : _snapshotBlock;

        MiniMeToken cloneToken = tokenFactory.createCloneToken(
            this,
            snapshot,
            _cloneTokenName,
            _cloneDecimalUnits,
            _cloneTokenSymbol,
            _transfersEnabled
        );

        cloneToken.changeController(msg.sender);

        // An event to make the token easy to find on the blockchain
        NewCloneToken(address(cloneToken), snapshot);
        return cloneToken;
    }

////////////////
// Generate and destroy tokens
////////////////

    /// @notice Generates `_amount` tokens that are assigned to `_owner`
    /// @param _owner The address that will be assigned the new tokens
    /// @param _amount The quantity of tokens generated
    /// @return True if the tokens are generated correctly
    function generateTokens(address _owner, uint _amount) onlyController public returns (bool) {
        uint curTotalSupply = totalSupply();
        require(curTotalSupply + _amount >= curTotalSupply); // Check for overflow
        uint previousBalanceTo = balanceOf(_owner);
        require(previousBalanceTo + _amount >= previousBalanceTo); // Check for overflow
        updateValueAtNow(totalSupplyHistory, curTotalSupply + _amount);
        updateValueAtNow(balances[_owner], previousBalanceTo + _amount);
        Transfer(0, _owner, _amount);
        return true;
    }


    /// @notice Burns `_amount` tokens from `_owner`
    /// @param _owner The address that will lose the tokens
    /// @param _amount The quantity of tokens to burn
    /// @return True if the tokens are burned correctly
    function destroyTokens(address _owner, uint _amount) onlyController public returns (bool) {
        uint curTotalSupply = totalSupply();
        require(curTotalSupply >= _amount);
        uint previousBalanceFrom = balanceOf(_owner);
        require(previousBalanceFrom >= _amount);
        updateValueAtNow(totalSupplyHistory, curTotalSupply - _amount);
        updateValueAtNow(balances[_owner], previousBalanceFrom - _amount);
        Transfer(_owner, 0, _amount);
        return true;
    }

////////////////
// Enable tokens transfers
////////////////


    /// @notice Enables token holders to transfer their tokens freely if true
    /// @param _transfersEnabled True if transfers are allowed in the clone
    function enableTransfers(bool _transfersEnabled) onlyController public {
        transfersEnabled = _transfersEnabled;
    }

////////////////
// Internal helper functions to query and set a value in a snapshot array
////////////////

    /// @dev `getValueAt` retrieves the number of tokens at a given block number
    /// @param checkpoints The history of values being queried
    /// @param _block The block number to retrieve the value at
    /// @return The number of tokens being queried
    function getValueAt(Checkpoint[] storage checkpoints, uint _block) constant internal returns (uint) {
        if (checkpoints.length == 0)
            return 0;

        // Shortcut for the actual value
        if (_block >= checkpoints[checkpoints.length-1].fromBlock)
            return checkpoints[checkpoints.length-1].value;
        if (_block < checkpoints[0].fromBlock)
            return 0;

        // Binary search of the value in the array
        uint min = 0;
        uint max = checkpoints.length-1;
        while (max > min) {
            uint mid = (max + min + 1) / 2;
            if (checkpoints[mid].fromBlock<=_block) {
                min = mid;
            } else {
                max = mid-1;
            }
        }
        return checkpoints[min].value;
    }

    /// @dev `updateValueAtNow` used to update the `balances` map and the
    ///  `totalSupplyHistory`
    /// @param checkpoints The history of data being updated
    /// @param _value The new number of tokens
    function updateValueAtNow(Checkpoint[] storage checkpoints, uint _value) internal {
        require(_value <= uint128(-1));

        if ((checkpoints.length == 0) || (checkpoints[checkpoints.length - 1].fromBlock < block.number)) {
            Checkpoint storage newCheckPoint = checkpoints[checkpoints.length++];
            newCheckPoint.fromBlock = uint128(block.number);
            newCheckPoint.value = uint128(_value);
        } else {
            Checkpoint storage oldCheckPoint = checkpoints[checkpoints.length - 1];
            oldCheckPoint.value = uint128(_value);
        }
    }

    /// @dev Internal function to determine if an address is a contract
    /// @param _addr The address being queried
    /// @return True if `_addr` is a contract
    function isContract(address _addr) constant internal returns(bool) {
        uint size;
        if (_addr == 0)
            return false;

        assembly {
            size := extcodesize(_addr)
        }

        return size>0;
    }

    /// @dev Helper function to return a min betwen the two uints
    function min(uint a, uint b) pure internal returns (uint) {
        return a < b ? a : b;
    }

    /// @notice The fallback function: If the contract's controller has not been
    ///  set to 0, then the `proxyPayment` method is called which relays the
    ///  ether and creates tokens as described in the token controller contract
    function () external payable {
        require(isContract(controller));
        // Adding the ` == true` makes the linter shut up so...
        require(ITokenController(controller).proxyPayment.value(msg.value)(msg.sender) == true);
    }

//////////
// Safety Methods
//////////

    /// @notice This method can be used by the controller to extract mistakenly
    ///  sent tokens to this contract.
    /// @param _token The address of the token contract that you want to recover
    ///  set to 0 in case you want to extract ether.
    function claimTokens(address _token) onlyController public {
        if (_token == 0x0) {
            controller.transfer(this.balance);
            return;
        }

        MiniMeToken token = MiniMeToken(_token);
        uint balance = token.balanceOf(this);
        token.transfer(controller, balance);
        ClaimedTokens(_token, controller, balance);
    }

////////////////
// Events
////////////////
    event ClaimedTokens(address indexed _token, address indexed _controller, uint _amount);
    event Transfer(address indexed _from, address indexed _to, uint256 _amount);
    event NewCloneToken(address indexed _cloneToken, uint _snapshotBlock);
    event Approval(
        address indexed _owner,
        address indexed _spender,
        uint256 _amount
        );

}


////////////////
// MiniMeTokenFactory
////////////////

/// @dev This contract is used to generate clone contracts from a contract.
///  In solidity this is the way to create a contract from a contract of the
///  same class
contract MiniMeTokenFactory {
    event NewFactoryCloneToken(address indexed _cloneToken, address indexed _parentToken, uint _snapshotBlock);

    /// @notice Update the DApp by creating a new token with new functionalities
    ///  the msg.sender becomes the controller of this clone token
    /// @param _parentToken Address of the token being cloned
    /// @param _snapshotBlock Block of the parent token that will
    ///  determine the initial distribution of the clone token
    /// @param _tokenName Name of the new token
    /// @param _decimalUnits Number of decimals of the new token
    /// @param _tokenSymbol Token Symbol for the new token
    /// @param _transfersEnabled If true, tokens will be able to be transferred
    /// @return The address of the new token contract
    function createCloneToken(
        MiniMeToken _parentToken,
        uint _snapshotBlock,
        string _tokenName,
        uint8 _decimalUnits,
        string _tokenSymbol,
        bool _transfersEnabled
    ) public returns (MiniMeToken)
    {
        MiniMeToken newToken = new MiniMeToken(
            this,
            _parentToken,
            _snapshotBlock,
            _tokenName,
            _decimalUnits,
            _tokenSymbol,
            _transfersEnabled
        );

        newToken.changeController(msg.sender);
        NewFactoryCloneToken(address(newToken), address(_parentToken), _snapshotBlock);
        return newToken;
    }
}
          

/*
 * SPDX-License-Identifier:    MIT
 */

pragma solidity ^0.4.24;


contract ACLSyntaxSugar {
    function arr() internal pure returns (uint256[]) {
        return new uint256[](0);
    }

    function arr(bytes32 _a) internal pure returns (uint256[] r) {
        return arr(uint256(_a));
    }

    function arr(bytes32 _a, bytes32 _b) internal pure returns (uint256[] r) {
        return arr(uint256(_a), uint256(_b));
    }

    function arr(address _a) internal pure returns (uint256[] r) {
        return arr(uint256(_a));
    }

    function arr(address _a, address _b) internal pure returns (uint256[] r) {
        return arr(uint256(_a), uint256(_b));
    }

    function arr(address _a, uint256 _b, uint256 _c) internal pure returns (uint256[] r) {
        return arr(uint256(_a), _b, _c);
    }

    function arr(address _a, uint256 _b, uint256 _c, uint256 _d) internal pure returns (uint256[] r) {
        return arr(uint256(_a), _b, _c, _d);
    }

    function arr(address _a, uint256 _b) internal pure returns (uint256[] r) {
        return arr(uint256(_a), uint256(_b));
    }

    function arr(address _a, address _b, uint256 _c, uint256 _d, uint256 _e) internal pure returns (uint256[] r) {
        return arr(uint256(_a), uint256(_b), _c, _d, _e);
    }

    function arr(address _a, address _b, address _c) internal pure returns (uint256[] r) {
        return arr(uint256(_a), uint256(_b), uint256(_c));
    }

    function arr(address _a, address _b, uint256 _c) internal pure returns (uint256[] r) {
        return arr(uint256(_a), uint256(_b), uint256(_c));
    }

    function arr(uint256 _a) internal pure returns (uint256[] r) {
        r = new uint256[](1);
        r[0] = _a;
    }

    function arr(uint256 _a, uint256 _b) internal pure returns (uint256[] r) {
        r = new uint256[](2);
        r[0] = _a;
        r[1] = _b;
    }

    function arr(uint256 _a, uint256 _b, uint256 _c) internal pure returns (uint256[] r) {
        r = new uint256[](3);
        r[0] = _a;
        r[1] = _b;
        r[2] = _c;
    }

    function arr(uint256 _a, uint256 _b, uint256 _c, uint256 _d) internal pure returns (uint256[] r) {
        r = new uint256[](4);
        r[0] = _a;
        r[1] = _b;
        r[2] = _c;
        r[3] = _d;
    }

    function arr(uint256 _a, uint256 _b, uint256 _c, uint256 _d, uint256 _e) internal pure returns (uint256[] r) {
        r = new uint256[](5);
        r[0] = _a;
        r[1] = _b;
        r[2] = _c;
        r[3] = _d;
        r[4] = _e;
    }
}


contract ACLHelpers {
    function decodeParamOp(uint256 _x) internal pure returns (uint8 b) {
        return uint8(_x >> (8 * 30));
    }

    function decodeParamId(uint256 _x) internal pure returns (uint8 b) {
        return uint8(_x >> (8 * 31));
    }

    function decodeParamsList(uint256 _x) internal pure returns (uint32 a, uint32 b, uint32 c) {
        a = uint32(_x);
        b = uint32(_x >> (8 * 4));
        c = uint32(_x >> (8 * 8));
    }
}
          

/*
 * SPDX-License-Identifier:    MIT
 */

pragma solidity ^0.4.24;


interface IACL {
    function initialize(address permissionsCreator) external;

    // TODO: this should be external
    // See https://github.com/ethereum/solidity/issues/4832
    function hasPermission(address who, address where, bytes32 what, bytes how) public view returns (bool);
}
          

/*
 * SPDX-License-Identifier:    MIT
 */

pragma solidity ^0.4.24;

import "../common/UnstructuredStorage.sol";
import "../kernel/IKernel.sol";


contract AppStorage {
    using UnstructuredStorage for bytes32;

    /* Hardcoded constants to save gas
    bytes32 internal constant KERNEL_POSITION = keccak256("aragonOS.appStorage.kernel");
    bytes32 internal constant APP_ID_POSITION = keccak256("aragonOS.appStorage.appId");
    */
    bytes32 internal constant KERNEL_POSITION = 0x4172f0f7d2289153072b0a6ca36959e0cbe2efc3afe50fc81636caa96338137b;
    bytes32 internal constant APP_ID_POSITION = 0xd625496217aa6a3453eecb9c3489dc5a53e6c67b444329ea2b2cbc9ff547639b;

    function kernel() public view returns (IKernel) {
        return IKernel(KERNEL_POSITION.getStorageAddress());
    }

    function appId() public view returns (bytes32) {
        return APP_ID_POSITION.getStorageBytes32();
    }

    function setKernel(IKernel _kernel) internal {
        KERNEL_POSITION.setStorageAddress(address(_kernel));
    }

    function setAppId(bytes32 _appId) internal {
        APP_ID_POSITION.setStorageBytes32(_appId);
    }
}
          

/*
 * SPDX-License-Identifier:    MIT
 */

pragma solidity ^0.4.24;

import "./AppStorage.sol";
import "../acl/ACLSyntaxSugar.sol";
import "../common/Autopetrified.sol";
import "../common/ConversionHelpers.sol";
import "../common/ReentrancyGuard.sol";
import "../common/VaultRecoverable.sol";
import "../evmscript/EVMScriptRunner.sol";


// Contracts inheriting from AragonApp are, by default, immediately petrified upon deployment so
// that they can never be initialized.
// Unless overriden, this behaviour enforces those contracts to be usable only behind an AppProxy.
// ReentrancyGuard, EVMScriptRunner, and ACLSyntaxSugar are not directly used by this contract, but
// are included so that they are automatically usable by subclassing contracts
contract AragonApp is AppStorage, Autopetrified, VaultRecoverable, ReentrancyGuard, EVMScriptRunner, ACLSyntaxSugar {
    string private constant ERROR_AUTH_FAILED = "APP_AUTH_FAILED";

    modifier auth(bytes32 _role) {
        require(canPerform(msg.sender, _role, new uint256[](0)), ERROR_AUTH_FAILED);
        _;
    }

    modifier authP(bytes32 _role, uint256[] _params) {
        require(canPerform(msg.sender, _role, _params), ERROR_AUTH_FAILED);
        _;
    }

    /**
    * @dev Check whether an action can be performed by a sender for a particular role on this app
    * @param _sender Sender of the call
    * @param _role Role on this app
    * @param _params Permission params for the role
    * @return Boolean indicating whether the sender has the permissions to perform the action.
    *         Always returns false if the app hasn't been initialized yet.
    */
    function canPerform(address _sender, bytes32 _role, uint256[] _params) public view returns (bool) {
        if (!hasInitialized()) {
            return false;
        }

        IKernel linkedKernel = kernel();
        if (address(linkedKernel) == address(0)) {
            return false;
        }

        return linkedKernel.hasPermission(
            _sender,
            address(this),
            _role,
            ConversionHelpers.dangerouslyCastUintArrayToBytes(_params)
        );
    }

    /**
    * @dev Get the recovery vault for the app
    * @return Recovery vault address for the app
    */
    function getRecoveryVault() public view returns (address) {
        // Funds recovery via a vault is only available when used with a kernel
        return kernel().getRecoveryVault(); // if kernel is not set, it will revert
    }
}
          

/*
 * SPDX-License-Identifier:    MIT
 */

pragma solidity ^0.4.24;

import "./TimeHelpers.sol";
import "./UnstructuredStorage.sol";


contract Initializable is TimeHelpers {
    using UnstructuredStorage for bytes32;

    // keccak256("aragonOS.initializable.initializationBlock")
    bytes32 internal constant INITIALIZATION_BLOCK_POSITION = 0xebb05b386a8d34882b8711d156f463690983dc47815980fb82aeeff1aa43579e;

    string private constant ERROR_ALREADY_INITIALIZED = "INIT_ALREADY_INITIALIZED";
    string private constant ERROR_NOT_INITIALIZED = "INIT_NOT_INITIALIZED";

    modifier onlyInit {
        require(getInitializationBlock() == 0, ERROR_ALREADY_INITIALIZED);
        _;
    }

    modifier isInitialized {
        require(hasInitialized(), ERROR_NOT_INITIALIZED);
        _;
    }

    /**
    * @return Block number in which the contract was initialized
    */
    function getInitializationBlock() public view returns (uint256) {
        return INITIALIZATION_BLOCK_POSITION.getStorageUint256();
    }

    /**
    * @return Whether the contract has been initialized by the time of the current block
    */
    function hasInitialized() public view returns (bool) {
        uint256 initializationBlock = getInitializationBlock();
        return initializationBlock != 0 && getBlockNumber() >= initializationBlock;
    }

    /**
    * @dev Function to be called by top level contract after initialization has finished.
    */
    function initialized() internal onlyInit {
        INITIALIZATION_BLOCK_POSITION.setStorageUint256(getBlockNumber());
    }

    /**
    * @dev Function to be called by top level contract after initialization to enable the contract
    *      at a future block number rather than immediately.
    */
    function initializedAt(uint256 _blockNumber) internal onlyInit {
        INITIALIZATION_BLOCK_POSITION.setStorageUint256(_blockNumber);
    }
}
          

/*
 * SPDX-License-Identifier:    MIT
 */

pragma solidity ^0.4.24;


contract IsContract {
    /*
    * NOTE: this should NEVER be used for authentication
    * (see pitfalls: https://github.com/fergarrui/ethereum-security/tree/master/contracts/extcodesize).
    *
    * This is only intended to be used as a sanity check that an address is actually a contract,
    * RATHER THAN an address not being a contract.
    */
    function isContract(address _target) internal view returns (bool) {
        if (_target == address(0)) {
            return false;
        }

        uint256 size;
        assembly { size := extcodesize(_target) }
        return size > 0;
    }
}
          

/*
 * SPDX-License-Identifier:    MIT
 */

pragma solidity ^0.4.24;

import "./Initializable.sol";


contract Petrifiable is Initializable {
    // Use block UINT256_MAX (which should be never) as the initializable date
    uint256 internal constant PETRIFIED_BLOCK = uint256(-1);

    function isPetrified() public view returns (bool) {
        return getInitializationBlock() == PETRIFIED_BLOCK;
    }

    /**
    * @dev Function to be called by top level contract to prevent being initialized.
    *      Useful for freezing base contracts when they're used behind proxies.
    */
    function petrify() internal onlyInit {
        initializedAt(PETRIFIED_BLOCK);
    }
}
          

/*
 * SPDX-License-Identifier:    MIT
 */

pragma solidity ^0.4.24;

import "../common/UnstructuredStorage.sol";


contract ReentrancyGuard {
    using UnstructuredStorage for bytes32;

    /* Hardcoded constants to save gas
    bytes32 internal constant REENTRANCY_MUTEX_POSITION = keccak256("aragonOS.reentrancyGuard.mutex");
    */
    bytes32 private constant REENTRANCY_MUTEX_POSITION = 0xe855346402235fdd185c890e68d2c4ecad599b88587635ee285bce2fda58dacb;

    string private constant ERROR_REENTRANT = "REENTRANCY_REENTRANT_CALL";

    modifier nonReentrant() {
        // Ensure mutex is unlocked
        require(!REENTRANCY_MUTEX_POSITION.getStorageBool(), ERROR_REENTRANT);

        // Lock mutex before function call
        REENTRANCY_MUTEX_POSITION.setStorageBool(true);

        // Perform function call
        _;

        // Unlock mutex after function call
        REENTRANCY_MUTEX_POSITION.setStorageBool(false);
    }
}
          

// Inspired by AdEx (https://github.com/AdExNetwork/adex-protocol-eth/blob/b9df617829661a7518ee10f4cb6c4108659dd6d5/contracts/libs/SafeERC20.sol)
// and 0x (https://github.com/0xProject/0x-monorepo/blob/737d1dc54d72872e24abce5a1dbe1b66d35fa21a/contracts/protocol/contracts/protocol/AssetProxy/ERC20Proxy.sol#L143)

pragma solidity ^0.4.24;

import "../lib/token/ERC20.sol";


library SafeERC20 {
    // Before 0.5, solidity has a mismatch between `address.transfer()` and `token.transfer()`:
    // https://github.com/ethereum/solidity/issues/3544
    bytes4 private constant TRANSFER_SELECTOR = 0xa9059cbb;

    string private constant ERROR_TOKEN_BALANCE_REVERTED = "SAFE_ERC_20_BALANCE_REVERTED";
    string private constant ERROR_TOKEN_ALLOWANCE_REVERTED = "SAFE_ERC_20_ALLOWANCE_REVERTED";

    function invokeAndCheckSuccess(address _addr, bytes memory _calldata)
        private
        returns (bool)
    {
        bool ret;
        assembly {
            let ptr := mload(0x40)    // free memory pointer

            let success := call(
                gas,                  // forward all gas
                _addr,                // address
                0,                    // no value
                add(_calldata, 0x20), // calldata start
                mload(_calldata),     // calldata length
                ptr,                  // write output over free memory
                0x20                  // uint256 return
            )

            if gt(success, 0) {
                // Check number of bytes returned from last function call
                switch returndatasize

                // No bytes returned: assume success
                case 0 {
                    ret := 1
                }

                // 32 bytes returned: check if non-zero
                case 0x20 {
                    // Only return success if returned data was true
                    // Already have output in ptr
                    ret := eq(mload(ptr), 1)
                }

                // Not sure what was returned: don't mark as success
                default { }
            }
        }
        return ret;
    }

    function staticInvoke(address _addr, bytes memory _calldata)
        private
        view
        returns (bool, uint256)
    {
        bool success;
        uint256 ret;
        assembly {
            let ptr := mload(0x40)    // free memory pointer

            success := staticcall(
                gas,                  // forward all gas
                _addr,                // address
                add(_calldata, 0x20), // calldata start
                mload(_calldata),     // calldata length
                ptr,                  // write output over free memory
                0x20                  // uint256 return
            )

            if gt(success, 0) {
                ret := mload(ptr)
            }
        }
        return (success, ret);
    }

    /**
    * @dev Same as a standards-compliant ERC20.transfer() that never reverts (returns false).
    *      Note that this makes an external call to the token.
    */
    function safeTransfer(ERC20 _token, address _to, uint256 _amount) internal returns (bool) {
        bytes memory transferCallData = abi.encodeWithSelector(
            TRANSFER_SELECTOR,
            _to,
            _amount
        );
        return invokeAndCheckSuccess(_token, transferCallData);
    }

    /**
    * @dev Same as a standards-compliant ERC20.transferFrom() that never reverts (returns false).
    *      Note that this makes an external call to the token.
    */
    function safeTransferFrom(ERC20 _token, address _from, address _to, uint256 _amount) internal returns (bool) {
        bytes memory transferFromCallData = abi.encodeWithSelector(
            _token.transferFrom.selector,
            _from,
            _to,
            _amount
        );
        return invokeAndCheckSuccess(_token, transferFromCallData);
    }

    /**
    * @dev Same as a standards-compliant ERC20.approve() that never reverts (returns false).
    *      Note that this makes an external call to the token.
    */
    function safeApprove(ERC20 _token, address _spender, uint256 _amount) internal returns (bool) {
        bytes memory approveCallData = abi.encodeWithSelector(
            _token.approve.selector,
            _spender,
            _amount
        );
        return invokeAndCheckSuccess(_token, approveCallData);
    }

    /**
    * @dev Static call into ERC20.balanceOf().
    * Reverts if the call fails for some reason (should never fail).
    */
    function staticBalanceOf(ERC20 _token, address _owner) internal view returns (uint256) {
        bytes memory balanceOfCallData = abi.encodeWithSelector(
            _token.balanceOf.selector,
            _owner
        );

        (bool success, uint256 tokenBalance) = staticInvoke(_token, balanceOfCallData);
        require(success, ERROR_TOKEN_BALANCE_REVERTED);

        return tokenBalance;
    }

    /**
    * @dev Static call into ERC20.allowance().
    * Reverts if the call fails for some reason (should never fail).
    */
    function staticAllowance(ERC20 _token, address _owner, address _spender) internal view returns (uint256) {
        bytes memory allowanceCallData = abi.encodeWithSelector(
            _token.allowance.selector,
            _owner,
            _spender
        );

        (bool success, uint256 allowance) = staticInvoke(_token, allowanceCallData);
        require(success, ERROR_TOKEN_ALLOWANCE_REVERTED);

        return allowance;
    }

    /**
    * @dev Static call into ERC20.totalSupply().
    * Reverts if the call fails for some reason (should never fail).
    */
    function staticTotalSupply(ERC20 _token) internal view returns (uint256) {
        bytes memory totalSupplyCallData = abi.encodeWithSelector(_token.totalSupply.selector);

        (bool success, uint256 totalSupply) = staticInvoke(_token, totalSupplyCallData);
        require(success, ERROR_TOKEN_ALLOWANCE_REVERTED);

        return totalSupply;
    }
}
          

/*
 * SPDX-License-Identifier:    MIT
 */

pragma solidity ^0.4.24;

import "./Uint256Helpers.sol";


contract TimeHelpers {
    using Uint256Helpers for uint256;

    /**
    * @dev Returns the current block number.
    *      Using a function rather than `block.number` allows us to easily mock the block number in
    *      tests.
    */
    function getBlockNumber() internal view returns (uint256) {
        return block.number;
    }

    /**
    * @dev Returns the current block number, converted to uint64.
    *      Using a function rather than `block.number` allows us to easily mock the block number in
    *      tests.
    */
    function getBlockNumber64() internal view returns (uint64) {
        return getBlockNumber().toUint64();
    }

    /**
    * @dev Returns the current timestamp.
    *      Using a function rather than `block.timestamp` allows us to easily mock it in
    *      tests.
    */
    function getTimestamp() internal view returns (uint256) {
        return block.timestamp; // solium-disable-line security/no-block-members
    }

    /**
    * @dev Returns the current timestamp, converted to uint64.
    *      Using a function rather than `block.timestamp` allows us to easily mock it in
    *      tests.
    */
    function getTimestamp64() internal view returns (uint64) {
        return getTimestamp().toUint64();
    }
}
          

pragma solidity ^0.4.24;


library Uint256Helpers {
    uint256 private constant MAX_UINT64 = uint64(-1);

    string private constant ERROR_NUMBER_TOO_BIG = "UINT64_NUMBER_TOO_BIG";

    function toUint64(uint256 a) internal pure returns (uint64) {
        require(a <= MAX_UINT64, ERROR_NUMBER_TOO_BIG);
        return uint64(a);
    }
}
          

/*
 * SPDX-License-Identifier:    MIT
 */

pragma solidity ^0.4.24;


library UnstructuredStorage {
    function getStorageBool(bytes32 position) internal view returns (bool data) {
        assembly { data := sload(position) }
    }

    function getStorageAddress(bytes32 position) internal view returns (address data) {
        assembly { data := sload(position) }
    }

    function getStorageBytes32(bytes32 position) internal view returns (bytes32 data) {
        assembly { data := sload(position) }
    }

    function getStorageUint256(bytes32 position) internal view returns (uint256 data) {
        assembly { data := sload(position) }
    }

    function setStorageBool(bytes32 position, bool data) internal {
        assembly { sstore(position, data) }
    }

    function setStorageAddress(bytes32 position, address data) internal {
        assembly { sstore(position, data) }
    }

    function setStorageBytes32(bytes32 position, bytes32 data) internal {
        assembly { sstore(position, data) }
    }

    function setStorageUint256(bytes32 position, uint256 data) internal {
        assembly { sstore(position, data) }
    }
}
          

/*
 * SPDX-License-Identifier:    MIT
 */

pragma solidity ^0.4.24;

import "../lib/token/ERC20.sol";
import "./EtherTokenConstant.sol";
import "./IsContract.sol";
import "./IVaultRecoverable.sol";
import "./SafeERC20.sol";


contract VaultRecoverable is IVaultRecoverable, EtherTokenConstant, IsContract {
    using SafeERC20 for ERC20;

    string private constant ERROR_DISALLOWED = "RECOVER_DISALLOWED";
    string private constant ERROR_VAULT_NOT_CONTRACT = "RECOVER_VAULT_NOT_CONTRACT";
    string private constant ERROR_TOKEN_TRANSFER_FAILED = "RECOVER_TOKEN_TRANSFER_FAILED";

    /**
     * @notice Send funds to recovery Vault. This contract should never receive funds,
     *         but in case it does, this function allows one to recover them.
     * @param _token Token balance to be sent to recovery vault.
     */
    function transferToVault(address _token) external {
        require(allowRecoverability(_token), ERROR_DISALLOWED);
        address vault = getRecoveryVault();
        require(isContract(vault), ERROR_VAULT_NOT_CONTRACT);

        uint256 balance;
        if (_token == ETH) {
            balance = address(this).balance;
            vault.transfer(balance);
        } else {
            ERC20 token = ERC20(_token);
            balance = token.staticBalanceOf(this);
            require(token.safeTransfer(vault, balance), ERROR_TOKEN_TRANSFER_FAILED);
        }

        emit RecoverToVault(vault, _token, balance);
    }

    /**
    * @dev By default deriving from AragonApp makes it recoverable
    * @param token Token address that would be recovered
    * @return bool whether the app allows the recovery
    */
    function allowRecoverability(address token) public view returns (bool) {
        return true;
    }

    // Cast non-implemented interface to be public so we can use it internally
    function getRecoveryVault() public view returns (address);
}
          

/*
 * SPDX-License-Identifier:    MIT
 */

pragma solidity ^0.4.24;

import "./IEVMScriptExecutor.sol";
import "./IEVMScriptRegistry.sol";

import "../apps/AppStorage.sol";
import "../kernel/KernelConstants.sol";
import "../common/Initializable.sol";


contract EVMScriptRunner is AppStorage, Initializable, EVMScriptRegistryConstants, KernelNamespaceConstants {
    string private constant ERROR_EXECUTOR_UNAVAILABLE = "EVMRUN_EXECUTOR_UNAVAILABLE";
    string private constant ERROR_PROTECTED_STATE_MODIFIED = "EVMRUN_PROTECTED_STATE_MODIFIED";

    /* This is manually crafted in assembly
    string private constant ERROR_EXECUTOR_INVALID_RETURN = "EVMRUN_EXECUTOR_INVALID_RETURN";
    */

    event ScriptResult(address indexed executor, bytes script, bytes input, bytes returnData);

    function getEVMScriptExecutor(bytes _script) public view returns (IEVMScriptExecutor) {
        return IEVMScriptExecutor(getEVMScriptRegistry().getScriptExecutor(_script));
    }

    function getEVMScriptRegistry() public view returns (IEVMScriptRegistry) {
        address registryAddr = kernel().getApp(KERNEL_APP_ADDR_NAMESPACE, EVMSCRIPT_REGISTRY_APP_ID);
        return IEVMScriptRegistry(registryAddr);
    }

    function runScript(bytes _script, bytes _input, address[] _blacklist)
        internal
        isInitialized
        protectState
        returns (bytes)
    {
        IEVMScriptExecutor executor = getEVMScriptExecutor(_script);
        require(address(executor) != address(0), ERROR_EXECUTOR_UNAVAILABLE);

        bytes4 sig = executor.execScript.selector;
        bytes memory data = abi.encodeWithSelector(sig, _script, _input, _blacklist);

        bytes memory output;
        assembly {
            let success := delegatecall(
                gas,                // forward all gas
                executor,           // address
                add(data, 0x20),    // calldata start
                mload(data),        // calldata length
                0,                  // don't write output (we'll handle this ourselves)
                0                   // don't write output
            )

            output := mload(0x40) // free mem ptr get

            switch success
            case 0 {
                // If the call errored, forward its full error data
                returndatacopy(output, 0, returndatasize)
                revert(output, returndatasize)
            }
            default {
                switch gt(returndatasize, 0x3f)
                case 0 {
                    // Need at least 0x40 bytes returned for properly ABI-encoded bytes values,
                    // revert with "EVMRUN_EXECUTOR_INVALID_RETURN"
                    // See remix: doing a `revert("EVMRUN_EXECUTOR_INVALID_RETURN")` always results in
                    // this memory layout
                    mstore(output, 0x08c379a000000000000000000000000000000000000000000000000000000000)         // error identifier
                    mstore(add(output, 0x04), 0x0000000000000000000000000000000000000000000000000000000000000020) // starting offset
                    mstore(add(output, 0x24), 0x000000000000000000000000000000000000000000000000000000000000001e) // reason length
                    mstore(add(output, 0x44), 0x45564d52554e5f4558454355544f525f494e56414c49445f52455455524e0000) // reason

                    revert(output, 100) // 100 = 4 + 3 * 32 (error identifier + 3 words for the ABI encoded error)
                }
                default {
                    // Copy result
                    //
                    // Needs to perform an ABI decode for the expected `bytes` return type of
                    // `executor.execScript()` as solidity will automatically ABI encode the returned bytes as:
                    //    [ position of the first dynamic length return value = 0x20 (32 bytes) ]
                    //    [ output length (32 bytes) ]
                    //    [ output content (N bytes) ]
                    //
                    // Perform the ABI decode by ignoring the first 32 bytes of the return data
                    let copysize := sub(returndatasize, 0x20)
                    returndatacopy(output, 0x20, copysize)

                    mstore(0x40, add(output, copysize)) // free mem ptr set
                }
            }
        }

        emit ScriptResult(address(executor), _script, _input, output);

        return output;
    }

    modifier protectState {
        address preKernel = address(kernel());
        bytes32 preAppId = appId();
        _; // exec
        require(address(kernel()) == preKernel, ERROR_PROTECTED_STATE_MODIFIED);
        require(appId() == preAppId, ERROR_PROTECTED_STATE_MODIFIED);
    }
}
          

/*
 * SPDX-License-Identifier:    MIT
 */

pragma solidity ^0.4.24;


interface IEVMScriptExecutor {
    function execScript(bytes script, bytes input, address[] blacklist) external returns (bytes);
    function executorType() external pure returns (bytes32);
}
          

/*
 * SPDX-License-Identifier:    MIT
 */

pragma solidity ^0.4.24;

import "./IEVMScriptExecutor.sol";


contract EVMScriptRegistryConstants {
    /* Hardcoded constants to save gas
    bytes32 internal constant EVMSCRIPT_REGISTRY_APP_ID = apmNamehash("evmreg");
    */
    bytes32 internal constant EVMSCRIPT_REGISTRY_APP_ID = 0xddbcfd564f642ab5627cf68b9b7d374fb4f8a36e941a75d89c87998cef03bd61;
}


interface IEVMScriptRegistry {
    function addScriptExecutor(IEVMScriptExecutor executor) external returns (uint id);
    function disableScriptExecutor(uint256 executorId) external;

    // TODO: this should be external
    // See https://github.com/ethereum/solidity/issues/4832
    function getScriptExecutor(bytes script) public view returns (IEVMScriptExecutor);
}
          

/*
 * SPDX-License-Identifier:    MIT
 */

pragma solidity ^0.4.24;

import "../acl/IACL.sol";
import "../common/IVaultRecoverable.sol";


interface IKernelEvents {
    event SetApp(bytes32 indexed namespace, bytes32 indexed appId, address app);
}


// This should be an interface, but interfaces can't inherit yet :(
contract IKernel is IKernelEvents, IVaultRecoverable {
    function acl() public view returns (IACL);
    function hasPermission(address who, address where, bytes32 what, bytes how) public view returns (bool);

    function setApp(bytes32 namespace, bytes32 appId, address app) public;
    function getApp(bytes32 namespace, bytes32 appId) public view returns (address);
}
          

/*
 * SPDX-License-Identifier:    MIT
 */

pragma solidity ^0.4.24;


contract KernelAppIds {
    /* Hardcoded constants to save gas
    bytes32 internal constant KERNEL_CORE_APP_ID = apmNamehash("kernel");
    bytes32 internal constant KERNEL_DEFAULT_ACL_APP_ID = apmNamehash("acl");
    bytes32 internal constant KERNEL_DEFAULT_VAULT_APP_ID = apmNamehash("vault");
    */
    bytes32 internal constant KERNEL_CORE_APP_ID = 0x3b4bf6bf3ad5000ecf0f989d5befde585c6860fea3e574a4fab4c49d1c177d9c;
    bytes32 internal constant KERNEL_DEFAULT_ACL_APP_ID = 0xe3262375f45a6e2026b7e7b18c2b807434f2508fe1a2a3dfb493c7df8f4aad6a;
    bytes32 internal constant KERNEL_DEFAULT_VAULT_APP_ID = 0x7e852e0fcfce6551c13800f1e7476f982525c2b5277ba14b24339c68416336d1;
}


contract KernelNamespaceConstants {
    /* Hardcoded constants to save gas
    bytes32 internal constant KERNEL_CORE_NAMESPACE = keccak256("core");
    bytes32 internal constant KERNEL_APP_BASES_NAMESPACE = keccak256("base");
    bytes32 internal constant KERNEL_APP_ADDR_NAMESPACE = keccak256("app");
    */
    bytes32 internal constant KERNEL_CORE_NAMESPACE = 0xc681a85306374a5ab27f0bbc385296a54bcd314a1948b6cf61c4ea1bc44bb9f8;
    bytes32 internal constant KERNEL_APP_BASES_NAMESPACE = 0xf1f3eb40f5bc1ad1344716ced8b8a0431d840b5783aea1fd01786bc26f35ac0f;
    bytes32 internal constant KERNEL_APP_ADDR_NAMESPACE = 0xd6f028ca0e8edb4a8c9757ca4fdccab25fa1e0317da1188108f7d2dee14902fb;
}
          

// See https://github.com/OpenZeppelin/openzeppelin-solidity/blob/d51e38758e1d985661534534d5c61e27bece5042/contracts/math/SafeMath.sol
// Adapted to use pragma ^0.4.24 and satisfy our linter rules

pragma solidity ^0.4.24;


/**
 * @title SafeMath
 * @dev Math operations with safety checks that revert on error
 */
library SafeMath {
    string private constant ERROR_ADD_OVERFLOW = "MATH_ADD_OVERFLOW";
    string private constant ERROR_SUB_UNDERFLOW = "MATH_SUB_UNDERFLOW";
    string private constant ERROR_MUL_OVERFLOW = "MATH_MUL_OVERFLOW";
    string private constant ERROR_DIV_ZERO = "MATH_DIV_ZERO";

    /**
    * @dev Multiplies two numbers, reverts on overflow.
    */
    function mul(uint256 _a, uint256 _b) internal pure returns (uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-solidity/pull/522
        if (_a == 0) {
            return 0;
        }

        uint256 c = _a * _b;
        require(c / _a == _b, ERROR_MUL_OVERFLOW);

        return c;
    }

    /**
    * @dev Integer division of two numbers truncating the quotient, reverts on division by zero.
    */
    function div(uint256 _a, uint256 _b) internal pure returns (uint256) {
        require(_b > 0, ERROR_DIV_ZERO); // Solidity only automatically asserts when dividing by 0
        uint256 c = _a / _b;
        // assert(_a == _b * c + _a % _b); // There is no case in which this doesn't hold

        return c;
    }

    /**
    * @dev Subtracts two numbers, reverts on overflow (i.e. if subtrahend is greater than minuend).
    */
    function sub(uint256 _a, uint256 _b) internal pure returns (uint256) {
        require(_b <= _a, ERROR_SUB_UNDERFLOW);
        uint256 c = _a - _b;

        return c;
    }

    /**
    * @dev Adds two numbers, reverts on overflow.
    */
    function add(uint256 _a, uint256 _b) internal pure returns (uint256) {
        uint256 c = _a + _b;
        require(c >= _a, ERROR_ADD_OVERFLOW);

        return c;
    }

    /**
    * @dev Divides two numbers and returns the remainder (unsigned integer modulo),
    * reverts when dividing by zero.
    */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b != 0, ERROR_DIV_ZERO);
        return a % b;
    }
}
          

// See https://github.com/OpenZeppelin/openzeppelin-solidity/blob/d51e38758e1d985661534534d5c61e27bece5042/contracts/math/SafeMath.sol
// Adapted for uint64, pragma ^0.4.24, and satisfying our linter rules
// Also optimized the mul() implementation, see https://github.com/aragon/aragonOS/pull/417

pragma solidity ^0.4.24;


/**
 * @title SafeMath64
 * @dev Math operations for uint64 with safety checks that revert on error
 */
library SafeMath64 {
    string private constant ERROR_ADD_OVERFLOW = "MATH64_ADD_OVERFLOW";
    string private constant ERROR_SUB_UNDERFLOW = "MATH64_SUB_UNDERFLOW";
    string private constant ERROR_MUL_OVERFLOW = "MATH64_MUL_OVERFLOW";
    string private constant ERROR_DIV_ZERO = "MATH64_DIV_ZERO";

    /**
    * @dev Multiplies two numbers, reverts on overflow.
    */
    function mul(uint64 _a, uint64 _b) internal pure returns (uint64) {
        uint256 c = uint256(_a) * uint256(_b);
        require(c < 0x010000000000000000, ERROR_MUL_OVERFLOW); // 2**64 (less gas this way)

        return uint64(c);
    }

    /**
    * @dev Integer division of two numbers truncating the quotient, reverts on division by zero.
    */
    function div(uint64 _a, uint64 _b) internal pure returns (uint64) {
        require(_b > 0, ERROR_DIV_ZERO); // Solidity only automatically asserts when dividing by 0
        uint64 c = _a / _b;
        // assert(_a == _b * c + _a % _b); // There is no case in which this doesn't hold

        return c;
    }

    /**
    * @dev Subtracts two numbers, reverts on overflow (i.e. if subtrahend is greater than minuend).
    */
    function sub(uint64 _a, uint64 _b) internal pure returns (uint64) {
        require(_b <= _a, ERROR_SUB_UNDERFLOW);
        uint64 c = _a - _b;

        return c;
    }

    /**
    * @dev Adds two numbers, reverts on overflow.
    */
    function add(uint64 _a, uint64 _b) internal pure returns (uint64) {
        uint64 c = _a + _b;
        require(c >= _a, ERROR_ADD_OVERFLOW);

        return c;
    }

    /**
    * @dev Divides two numbers and returns the remainder (unsigned integer modulo),
    * reverts when dividing by zero.
    */
    function mod(uint64 a, uint64 b) internal pure returns (uint64) {
        require(b != 0, ERROR_DIV_ZERO);
        return a % b;
    }
}
          

// See https://github.com/OpenZeppelin/openzeppelin-solidity/blob/a9f910d34f0ab33a1ae5e714f69f9596a02b4d91/contracts/token/ERC20/ERC20.sol

pragma solidity ^0.4.24;


/**
 * @title ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/20
 */
contract ERC20 {
    function totalSupply() public view returns (uint256);

    function balanceOf(address _who) public view returns (uint256);

    function allowance(address _owner, address _spender)
        public view returns (uint256);

    function transfer(address _to, uint256 _value) public returns (bool);

    function approve(address _spender, uint256 _value)
        public returns (bool);

    function transferFrom(address _from, address _to, uint256 _value)
        public returns (bool);

    event Transfer(
        address indexed from,
        address indexed to,
        uint256 value
    );

    event Approval(
        address indexed owner,
        address indexed spender,
        uint256 value
    );
}