owncloud/core

<?php
/**
 * @author Robin Appelman <icewind@owncloud.com>
 * @author Thomas Müller <thomas.mueller@tmit.eu>
 *
 * @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/>
 *
 */

namespace OC\Hooks;

trait EmitterTrait {
    /**
     * @var (callable[])[] $listeners
     */
    protected $listeners = [];

    /**
     * @param string $scope
     * @param string $method
     * @param callable $callback
     */
    public function listen($scope, $method, callable $callback) {
        $eventName = $scope . '::' . $method;
        if (!isset($this->listeners[$eventName])) {
            $this->listeners[$eventName] = [];
        }
        if (\array_search($callback, $this->listeners[$eventName], true) === false) {
            $this->listeners[$eventName][] = $callback;
        }
    }

    /**
     * @param string $scope optional
     * @param string $method optional
     * @param callable $callback optional
     */
    public function removeListener($scope = null, $method = null, callable $callback = null) {
        $names = [];
        $allNames = \array_keys($this->listeners);
        if ($scope and $method) {
            $name = $scope . '::' . $method;
            if (isset($this->listeners[$name])) {
                $names[] = $name;
            }
        } elseif ($scope) {
            foreach ($allNames as $name) {
                $parts = \explode('::', $name, 2);
                if ($parts[0] == $scope) {
                    $names[] = $name;
                }
            }
        } elseif ($method) {
            foreach ($allNames as $name) {
                $parts = \explode('::', $name, 2);
                if ($parts[1] == $method) {
                    $names[] = $name;
                }
            }
        } else {
            $names = $allNames;
        }

        foreach ($names as $name) {
            if ($callback) {
                $index = \array_search($callback, $this->listeners[$name], true);
                if ($index !== false) {
                    unset($this->listeners[$name][$index]);
                }
            } else {
                $this->listeners[$name] = [];
            }
        }
    }

    /**
     * @param string $scope
     * @param string $method
     * @param array $arguments optional
     */
    protected function emit($scope, $method, array $arguments = []) {
        $eventName = $scope . '::' . $method;
        if (isset($this->listeners[$eventName])) {
            foreach ($this->listeners[$eventName] as $callback) {
                \call_user_func_array($callback, $arguments);
            }
        }
    }
}