escrow_goods.sol

/* A contract to store goods with escrowed funds. */

/* Deployment:
Contract:
Owner: seller
Last address: dynamic
ABI: [{"constant":true,"inputs":[{"name":"","type":"uint256"}],"name":"escrows","outputs":[{"name":"buyer","type":"address"},{"name":"lockedFunds","type":"uint256"},{"name":"frozenTime","type":"uint256"},{"name":"frozenFunds","type":"uint256"},{"name":"buyerNo","type":"uint256"},{"name":"sellerNo","type":"uint256"}],"payable":false,"type":"function"},{"constant":true,"inputs":[],"name":"count","outputs":[{"name":"","type":"uint16"}],"payable":false,"type":"function"},{"constant":false,"inputs":[{"name":"datainfo","type":"string"},{"name":"_version","type":"uint256"}],"name":"cancel","outputs":[],"payable":false,"type":"function"},{"constant":true,"inputs":[],"name":"seller","outputs":[{"name":"","type":"address"}],"payable":false,"type":"function"},{"constant":true,"inputs":[],"name":"freezePeriod","outputs":[{"name":"","type":"uint256"}],"payable":false,"type":"function"},{"constant":false,"inputs":[{"name":"id","type":"uint256"},{"name":"datainfo","type":"string"},{"name":"_version","type":"uint256"},{"name":"_count","type":"uint16"}],"name":"buy","outputs":[],"payable":false,"type":"function"},{"constant":true,"inputs":[],"name":"status","outputs":[{"name":"","type":"uint16"}],"payable":false,"type":"function"},{"constant":true,"inputs":[],"name":"rewardPromille","outputs":[{"name":"","type":"uint256"}],"payable":false,"type":"function"},{"constant":false,"inputs":[{"name":"id","type":"uint256"}],"name":"getMoney","outputs":[],"payable":false,"type":"function"},{"constant":false,"inputs":[{"name":"id","type":"uint256"},{"name":"datainfo","type":"string"},{"name":"_version","type":"uint256"}],"name":"no","outputs":[],"payable":false,"type":"function"},{"constant":false,"inputs":[{"name":"id","type":"uint256"},{"name":"datainfo","type":"string"},{"name":"_version","type":"uint256"},{"name":"_count","type":"uint16"},{"name":"recipient","type":"address"},{"name":"amount","type":"uint256"}],"name":"reject","outputs":[],"payable":false,"type":"function"},{"constant":false,"inputs":[],"name":"kill","outputs":[],"payable":false,"type":"function"},{"constant":true,"inputs":[],"name":"totalEscrows","outputs":[{"name":"","type":"uint256"}],"payable":false,"type":"function"},{"constant":false,"inputs":[{"name":"id","type":"uint256"},{"name":"who","type":"address"},{"name":"payment","type":"uint256"},{"name":"datainfo","type":"string"},{"name":"_version","type":"uint256"}],"name":"arbYes","outputs":[],"payable":false,"type":"function"},{"constant":true,"inputs":[],"name":"feeFunds","outputs":[{"name":"","type":"uint256"}],"payable":false,"type":"function"},{"constant":false,"inputs":[{"name":"id","type":"uint256"},{"name":"datainfo","type":"string"},{"name":"_version","type":"uint256"}],"name":"yes","outputs":[],"payable":false,"type":"function"},{"constant":true,"inputs":[{"name":"","type":"address"}],"name":"buyers","outputs":[{"name":"","type":"uint256"}],"payable":false,"type":"function"},{"constant":true,"inputs":[],"name":"availableCount","outputs":[{"name":"","type":"uint16"}],"payable":false,"type":"function"},{"constant":true,"inputs":[],"name":"price","outputs":[{"name":"","type":"uint256"}],"payable":false,"type":"function"},{"constant":false,"inputs":[{"name":"id","type":"uint256"},{"name":"datainfo","type":"string"},{"name":"_version","type":"uint256"},{"name":"_count","type":"uint16"}],"name":"accept","outputs":[],"payable":false,"type":"function"},{"constant":false,"inputs":[],"name":"unbuy","outputs":[],"payable":false,"type":"function"},{"constant":false,"inputs":[],"name":"getFees","outputs":[],"payable":false,"type":"function"},{"constant":true,"inputs":[],"name":"feePromille","outputs":[{"name":"","type":"uint256"}],"payable":false,"type":"function"},{"constant":true,"inputs":[],"name":"pendingCount","outputs":[{"name":"","type":"uint16"}],"payable":false,"type":"function"},{"constant":true,"inputs":[],"name":"arbiter","outputs":[{"name":"","type":"address"}],"payable":false,"type":"function"},{"inputs":[{"name":"_arbiter","type":"address"},{"name":"_freezePeriod","type":"uint256"},{"name":"_feePromille","type":"uint256"},{"name":"_rewardPromille","type":"uint256"},{"name":"_count","type":"uint16"},{"name":"_price","type":"uint256"}],"type":"constructor"},{"anonymous":false,"inputs":[{"indexed":false,"name":"message","type":"string"}],"name":"log_event","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"lockid","type":"uint256"},{"indexed":false,"name":"datainfo","type":"string"},{"indexed":true,"name":"version","type":"uint256"},{"indexed":false,"name":"datatype","type":"uint256"},{"indexed":true,"name":"sender","type":"address"},{"indexed":false,"name":"count","type":"uint256"},{"indexed":false,"name":"payment","type":"uint256"}],"name":"content","type":"event"}]
Optimized: yes
Solidity version: v0.4.2-nightly.2016.9.9
*/

pragma solidity ^0.4.0;

contract escrow_goods {

    struct EscrowInfo {

        address buyer;
        uint lockedFunds;
        uint frozenTime;
        uint frozenFunds;
        uint buyerNo;
        uint sellerNo;
    }

    //data

    uint constant arbitragePeriod = 30 days;
    uint constant safeGas = 25000;

    //seller/owner of the goods
    address public seller;

    //escrow related

    address public arbiter;

    uint public freezePeriod;
    //each lock fee in promilles.
    uint public feePromille;
    //reward in promilles. promille = percent * 10, eg 1,5% reward = 15 rewardPromille
    uint public rewardPromille;

    uint public feeFunds;
    uint public totalEscrows;

    mapping (uint => EscrowInfo) public escrows;

    //goods related

    //status of the goods: Available, Pending, Sold, Canceled
    uint16 public status;
    //how many for sale
    uint16 public count;
    //price per item
    uint public price;

    uint16 public availableCount;
    uint16 public pendingCount;

    mapping (address => uint) public buyers;

    uint16 atomicLock;

    //events

    event log_event(string message);
    event content(uint indexed lockid, string datainfo, uint indexed version, uint datatype, address indexed sender, uint count, uint payment);
    modifier onlyowner() { if (msg.sender == seller) _; }

    //modules

    function escrow_goods(address _arbiter, uint _freezePeriod, uint _feePromille, uint _rewardPromille,
                          uint16 _count, uint _price) {

        seller = msg.sender;

        // all variables are always initialized to 0, save gas

        //escrow related
        arbiter = _arbiter;
        freezePeriod = _freezePeriod;
        feePromille = _feePromille;
        rewardPromille = _rewardPromille;

        //goods related
        //status = Available
        status = 1;
        count = _count;
        price = _price;

        availableCount = count;
    }

    function kill() {

        //do not allow killing contract with active escrows
        if(totalEscrows > 0) {
            log_event("totalEscrows > 0");
            return;
        }
        //do not allow killing contract with unclaimed escrow fees
        if(feeFunds > 0) {
            log_event("feeFunds > 0");
            return;
        }
        //only allow the seller to kill contract
        if(msg.sender != seller) {
            log_event("msg.sender != seller");
            return;
        }
        suicide(msg.sender);
    }

    function safeSend(address addr, uint value) internal returns (bool) {

        if(atomicLock > 0) throw;
        atomicLock = 1;
        if (!(addr.call.gas(safeGas).value(value)())) {
            atomicLock = 0;
            return false;
        }
        atomicLock = 0;
        return true;
    }

    //escrow API

    //vote YES - immediately sends funds to the peer
    function yes(uint id, string datainfo, uint _version) {

        EscrowInfo info = escrows[id];

        if(info.lockedFunds == 0) {
            log_event("info.lockedFunds == 0");
            return;
        }
        if(msg.sender != info.buyer && msg.sender != seller) {
            log_event("msg.sender != info.buyer && msg.sender != seller");
            return;
        }

        uint payment = info.lockedFunds;
        if(payment > this.balance) {
            //HACK: should not get here - funds cannot be unlocked in this case
            log_event("payment > this.balance");
            return;
        }

        if(msg.sender == info.buyer) {
            //send funds to seller
            if(!safeSend(seller, payment)) {
                log_event("!safeSend(seller, payment)");
                return;
            }
        } else if(msg.sender == seller) {
            //send funds to buyer
            if(!safeSend(info.buyer, payment)) {
                log_event("!safeSend(info.buyer, payment)");
                return;
            }
        } else {
            //HACK: should not get here
            log_event("unknown msg.sender");
            return;
        }

        //remove record from escrows
        if(totalEscrows > 0) totalEscrows -= 1;
        info.lockedFunds = 0;

        content(id, datainfo, _version, 11, msg.sender, 0, payment);
    }

    //vote NO - freeze funds for arbitrage
    function no(uint id, string datainfo, uint _version) {

        EscrowInfo info = escrows[id];

        if(info.lockedFunds == 0) {
            log_event("info.lockedFunds == 0");
            return;
        }
        if(msg.sender != info.buyer && msg.sender != seller) {
            log_event("msg.sender != info.buyer && msg.sender != seller");
            return;
        }

        //freeze funds
        //only allow one time freeze
        if(info.frozenFunds == 0) {
            info.frozenFunds = info.lockedFunds;
            info.frozenTime = now;
        }

        if(msg.sender == info.buyer) {
            info.buyerNo = 1;
        }
        else if(msg.sender == seller) {
            info.sellerNo = 1;
        } else {
            //HACK: should not get here
            log_event("unknown msg.sender");
            return;
        }

        content(id, datainfo, _version, 12, msg.sender, 0, info.lockedFunds);
    }

    //arbiter's decision on the case.
    //arbiter can only decide when both buyer and seller voted NO
    //arbiter decides on his own reward but not bigger than announced percentage (rewardPromille)
    function arbYes(uint id, address who, uint payment, string datainfo, uint _version) {
        
        if(msg.sender != arbiter) return;

        EscrowInfo info = escrows[id];

        if(info.lockedFunds == 0) {
            log_event("info.lockedFunds == 0");
            return;
        }
        if(info.frozenFunds == 0) {
            log_event("info.frozenFunds == 0");
            return;
        }

        if(who != seller && who != info.buyer) {
            log_event("who != seller && who != info.buyer");
            return;
        }
        //requires both NO to arbitrage
        if(info.buyerNo == 0 || info.sellerNo == 0) {
            log_event("info.buyerNo == 0 || info.sellerNo == 0");
            return;
        }

        if(payment > info.lockedFunds) {
            log_event("payment > info.lockedFunds");
            return;
        }
        if(payment > this.balance) {
            //HACK: should not get here - funds cannot be unlocked in this case
            log_event("payment > this.balance");
            return;
        }

        //limit payment
        uint reward = (info.lockedFunds * rewardPromille) / 1000;
        if(reward > (info.lockedFunds - payment)) {
            log_event("reward > (info.lockedFunds - payment)");
            return;
        }

        //send funds to the winner
        if(!safeSend(who, payment)) {
            log_event("!safeSend(who, payment)");
            return;
        }

        //send the rest as reward
        info.lockedFunds -= payment;
        feeFunds += info.lockedFunds;
        info.lockedFunds = 0;

        content(id, datainfo, _version, 13, msg.sender, 0, payment);
    }

    //allow arbiter to get his collected fees
    function getFees() {

        if(msg.sender != arbiter) {
            log_event("msg.sender != arbiter");
            return;
        }
        if(feeFunds > this.balance) {
            //HACK: should not get here - funds cannot be unlocked in this case
            log_event("feeFunds > this.balance");
            return;
        }
        
        if(!safeSend(arbiter, feeFunds)) {
            log_event("!safeSend(arbiter, feeFunds)");
            return;
        }

        feeFunds = 0;
    }

    //allow buyer or seller take timeouted funds.
    //buyer can get funds if seller is silent and seller can get funds if buyer is silent (after freezePeriod)
    //buyer can get back funds under arbitrage if arbiter is silent (after arbitragePeriod)
    function getMoney(uint id) {

        EscrowInfo info = escrows[id];

        if(info.lockedFunds == 0) {
            log_event("info.lockedFunds == 0");
            return;
        }
        //HACK: this check is necessary since frozenTime == 0 at escrow creation
        if(info.frozenFunds == 0) {
            log_event("info.frozenFunds == 0");
            return;
        }

        //timout for voting not over yet
        if(now < (info.frozenTime + freezePeriod)) {
            log_event("now < (info.frozenTime + freezePeriod)");
            return;
        }

        uint payment = info.lockedFunds;
        if(payment > this.balance) {
            //HACK: should not get here - funds cannot be unlocked in this case
            log_event("payment > this.balance");
            return;
        }

        //both has voted - money is under arbitrage
        if(info.buyerNo != 0 && info.sellerNo != 0) {

            //arbitrage timeout is not over yet
            if(now < (info.frozenTime + freezePeriod + arbitragePeriod)) {
                log_event("now < (info.frozenTime + freezePeriod + arbitragePeriod)");
                return;
            }

            //arbiter was silent so redeem the funds to the buyer
            if(!safeSend(info.buyer, payment)) {
                log_event("!safeSend(info.buyer, payment)");
                return;
            }
            info.lockedFunds = 0;
            return;
        }

        if(info.buyerNo != 0) {

            if(!safeSend(info.buyer, payment)) {
                log_event("!safeSend(info.buyer, payment)");
                return;
            }
            info.lockedFunds = 0;
            return;
        }
        if(info.sellerNo != 0) {

            if(!safeSend(seller, payment)) {
                log_event("!safeSend(seller, payment)");
                return;
            }
            info.lockedFunds = 0;
            return;
        }
    }

    //goods API

    //buy with escrow. id - escrow info id
    function buy(uint id, string datainfo, uint _version, uint16 _count) {

        //reject money transfers for bad item status

        if(status != 1) throw;
        if(msg.value < (price * _count)) throw;
        if(_count > availableCount) throw;
        if(feePromille > 1000) throw;
        if(rewardPromille > 1000) throw;
        if((feePromille + rewardPromille) > 1000) throw;

        //create default EscrowInfo struct or access existing
        EscrowInfo info = escrows[id];

        //lock only once for a given id
        if(info.lockedFunds > 0) throw;

        //lock funds

        uint fee = (msg.value * feePromille) / 1000;
        //limit fees
        if(fee > msg.value) throw;

        uint funds = (msg.value - fee);
        feeFunds += fee;
        totalEscrows += 1;

        info.buyer = msg.sender;
        info.lockedFunds = funds;
        info.frozenFunds = 0;
        info.buyerNo = 0;
        info.sellerNo = 0;

        pendingCount += _count;
        buyers[msg.sender] = 1;

        //Buy order to event log
        content(id, datainfo, _version, 1, msg.sender, _count, msg.value);
    }

    function accept(uint id, string datainfo, uint _version, uint16 _count) onlyowner {
        
        if(_count > availableCount) {
            log_event("_count > availableCount");
            return;
        }
        if(_count > pendingCount) {
            log_event("_count > pendingCount");
            return;
        }

        pendingCount -= _count;
        availableCount -= _count;

        //Accept order to event log
        content(id, datainfo, _version, 2, msg.sender, _count, 0);
    }

    function reject(uint id, string datainfo, uint _version, uint16 _count, address recipient, uint amount) onlyowner {
        
        if(_count > pendingCount) {
            log_event("_count > pendingCount");
            return;
        }

        pendingCount -= _count;

        //send money back
        yes(id, datainfo, _version);

        //Reject order to event log
        //HACK: "yes" call above may fail and this event will be non-relevant. Do not rely on it.
        content(id, datainfo, _version, 3, msg.sender, _count, amount);
    }

    function cancel(string datainfo, uint _version) onlyowner {

        //Canceled status
        status = 2;

        //Cancel order to event log
        content(0, datainfo, _version, 4, msg.sender, availableCount, 0);
    }

    //remove buyer from the watchlist
    function unbuy() {

        buyers[msg.sender] = 0;
    }
}