pragma solidity ^0.4.24;

contract TokenUseAuthority {

    mapping (address => bool) public whiteList;

    constructor(address[] _whitelists) public {
        for (uint i = 0; i < _whitelists.length; i ++) {
            whiteList[_whitelists[i]] = true;
        }
    }

    function canCall(
        address _src, address _dst, bytes4 _sig
    ) public view returns (bool) {
        return (whiteList[_src] && _sig == bytes4(keccak256("addActivity(uint256,address,uint256)"))) ||
        ( whiteList[_src] && _sig == bytes4(keccak256("removeActivity(uint256,address)")));
    }
}