AragonApp.sol

/*
 * 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";
import "../lib/standards/ERC165.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 ERC165, 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
    }

    /**
    * @dev Query if a contract implements a certain interface
    * @param _interfaceId The interface identifier being queried, as specified in ERC-165
    * @return True if the contract implements the requested interface and if its not 0xffffffff, false otherwise
    */
    function supportsInterface(bytes4 _interfaceId) public pure returns (bool) {
        return super.supportsInterface(_interfaceId) || _interfaceId == ARAGON_APP_INTERFACE_ID;
    }
}