owncloud/core

<?php
/**
 * @author Bart Visscher <bartv@thisnet.nl>
 * @author Jakob Sack <mail@jakobsack.de>
 * @author Jörn Friedrich Dreyer <jfd@butonic.de>
 * @author Lukas Reschke <lukas@statuscode.ch>
 * @author Morris Jobke <hey@morrisjobke.de>
 * @author Robin Appelman <icewind@owncloud.com>
 * @author Robin McCorkell <robin@mccorkell.me.uk>
 * @author Sam Tuke <mail@samtuke.com>
 * @author Thomas Müller <thomas.mueller@tmit.eu>
 * @author Vincent Petry <pvince81@owncloud.com>
 *
 * @copyright Copyright (c) 2018, ownCloud GmbH
 * @license AGPL-3.0
 *
 * This code is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License, version 3,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License, version 3,
 * along with this program.  If not, see <http://www.gnu.org/licenses/>
 *
 */
class OC_Hook {
    private static $registered = [];

    /**
     * connects a function to a hook
     *
     * @param string $signalClass class name of emitter
     * @param string $signalName name of signal
     * @param string|object $slotClass class name of slot
     * @param string $slotName name of slot
     * @return bool
     *
     * This function makes it very easy to connect to use hooks.
     *
     * TODO: write example
     */
    public static function connect($signalClass, $signalName, $slotClass, $slotName) {
        // If we're trying to connect to an emitting class that isn't
        // yet registered, register it
        if (!\array_key_exists($signalClass, self::$registered)) {
            self::$registered[$signalClass] = [];
        }
        // If we're trying to connect to an emitting method that isn't
        // yet registered, register it with the emitting class
        if (!\array_key_exists($signalName, self::$registered[$signalClass])) {
            self::$registered[$signalClass][$signalName] = [];
        }

        // don't connect hooks twice
        foreach (self::$registered[$signalClass][$signalName] as $hook) {
            if ($hook['class'] === $slotClass and $hook['name'] === $slotName) {
                return false;
            }
        }
        // Connect the hook handler to the requested emitter
        self::$registered[$signalClass][$signalName][] = [
                "class" => $slotClass,
                "name" => $slotName
        ];

        // No chance for failure ;-)
        return true;
    }

    /**
     * emits a signal
     *
     * @param string $signalClass class name of emitter
     * @param string $signalName name of signal
     * @param mixed $params default: array() array with additional data
     * @return bool true if slots exists or false if not
     * @throws \OC\HintException
     * @throws \OC\ServerNotAvailableException Emits a signal. To get data from the slot use references!
     *
     * TODO: write example
     */
    public static function emit($signalClass, $signalName, $params = []) {
        // Return false if no hook handlers are listening to this
        // emitting class
        if (!\array_key_exists($signalClass, self::$registered)) {
            return false;
        }

        // Return false if no hook handlers are listening to this
        // emitting method
        if (!\array_key_exists($signalName, self::$registered[$signalClass])) {
            return false;
        }

        // Call all slots
        foreach (self::$registered[$signalClass][$signalName] as $i) {
            try {
                \call_user_func([$i["class"], $i["name"]], $params);
            } catch (Exception $e) {
                \OC::$server->getLogger()->logException($e);
                if ($e instanceof \OC\HintException) {
                    throw $e;
                }
                if ($e instanceof \OC\ServerNotAvailableException) {
                    throw $e;
                }
            }
        }

        return true;
    }

    /**
     * clear hooks
     * @param string $signalClass
     * @param string $signalName
     */
    public static function clear($signalClass='', $signalName='') {
        if ($signalClass) {
            if ($signalName) {
                self::$registered[$signalClass][$signalName]= [];
            } else {
                self::$registered[$signalClass]= [];
            }
        } else {
            self::$registered= [];
        }
    }

    /**
     * DO NOT USE!
     * For unit tests ONLY!
     */
    public static function getHooks() {
        return self::$registered;
    }
}