pragma solidity ^0.4.4; import "./Ownable.sol"; /* * Stoppable * Abstract contract that allows children to implement an * emergency stop mechanism. */ contract Stoppable is Ownable { bool public stopped; modifier stopInEmergency { if (!stopped) _; } modifier onlyInEmergency { if (stopped) _; } function emergencyStop() external onlyOwner { stopped = true; } function release() external onlyOwner onlyInEmergency { stopped = false; } }