token_escrow.abi.json

[{"constant":false,"inputs":[{"name":"numTokens","type":"uint256"}],"name":"fillOrder","outputs":[{"name":"","type":"bool"}],"type":"function"},{"constant":true,"inputs":[],"name":"owner","outputs":[{"name":"","type":"address"}],"type":"function"},{"constant":false,"inputs":[{"name":"_from","type":"address"},{"name":"numTokens","type":"uint256"}],"name":"fillOrder","outputs":[{"name":"","type":"bool"}],"type":"function"},{"constant":false,"inputs":[],"name":"cancel","outputs":[],"type":"function"},{"constant":false,"inputs":[{"name":"to","type":"address"}],"name":"transferOwnership","outputs":[],"type":"function"},{"inputs":[{"name":"_token","type":"address"},{"name":"_weiPerToken","type":"uint256"}],"type":"constructor"},{"anonymous":false,"inputs":[{"indexed":false,"name":"_from","type":"address"},{"indexed":false,"name":"numTokens","type":"uint256"}],"name":"OrderFilled","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"from","type":"address"},{"indexed":true,"name":"to","type":"address"}],"name":"OwnershipTransfer","type":"event"}]

token_escrow.sol.js

contract owned {
    function owned() {
        owner = msg.sender;
    }

    address public owner;

    modifier onlyowner { if (msg.sender != owner) throw; _ }

    event OwnershipTransfer(address indexed from, address indexed to);

    function transferOwnership(address to) public onlyowner {
        owner = to;
        OwnershipTransfer(msg.sender, to);
    }
}
// Token standard API
// https://github.com/ethereum/EIPs/issues/20
contract ERC20 {
    function totalSupply() constant returns (uint supply);
    function balanceOf(address who) constant returns (uint value);
    function allowance(address owner, address spender) constant returns (uint _allowance);
    function transfer(address to, uint value) returns (bool ok);
    function transferFrom(address from, address to, uint value) returns (bool ok);
    function approve(address spender, uint value) returns (bool ok);
    event Transfer(address indexed from, address indexed to, uint value);
    event Approval(address indexed owner, address indexed spender, uint value);
}
contract Order is owned {
    ERC20 token;
    uint weiPerToken;

    function Order(address _token, uint _weiPerToken) {
        token = ERC20(_token);
        weiPerToken = _weiPerToken;
    }

    function fillOrder(uint numTokens) public returns (bool) {
        return fillOrder(msg.sender, numTokens);
    }

    function sendRobust(address to, uint value) internal {
        if (!to.send(value)) {
            if (!to.call.value(value)()) throw;
        }
    }

    event OrderFilled(address _from, uint numTokens);

    function fillOrder(address _from, uint numTokens) public returns (bool) {
        if (this.balance < numTokens * weiPerToken) throw;

        if (!token.transferFrom(_from, owner, numTokens)) return false;
        sendRobust(_from, numTokens * weiPerToken);
        OrderFilled(_from, numTokens);
        return true;
    }

    function () {
        // allow receipt of funds
        if (msg.value > 0) return;

        uint allowance = token.allowance(msg.sender, address(this));
        if (allowance > 0) {
            if (this.balance < allowance * weiPerToken) {
                fillOrder(msg.sender, this.balance / weiPerToken);
            } else {
                fillOrder(msg.sender, allowance);
            }
        }
    }

    function cancel() onlyowner {
        selfdestruct(owner);
    }
}