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<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// Moodle 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
namespace core\event;
defined('MOODLE_INTERNAL') || die();
/**
* New event manager class.
*
* @package core
* @since Moodle 2.6
* @copyright 2013 Petr Skoda {@link http://skodak.org}
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
/**
* Class used for event dispatching.
*
* Note: Do NOT use directly in your code, it is intended to be used from
* base event class only.
*/
class manager {
/** @var array buffer of event for dispatching */
protected static $buffer = array();
/** @var array buffer for events that were not sent to external observers when DB transaction in progress */
protected static $extbuffer = array();
/** @var bool evert dispatching already in progress - prevents nesting */
protected static $dispatching = false;
/** @var array cache of all observers */
protected static $allobservers = null;
/** @var bool should we reload observers after the test? */
protected static $reloadaftertest = false;
/**
* Trigger new event.
*
* @internal to be used only from \core\event\base::trigger() method.
* @param \core\event\base $event
*
* @throws \coding_Exception if used directly.
*/
public static function dispatch(\core\event\base $event) {
if (during_initial_install()) {
return;
}
if (!$event->is_triggered() or $event->is_dispatched()) {
throw new \coding_exception('Illegal event dispatching attempted.');
}
self::$buffer[] = $event;
if (self::$dispatching) {
return;
}
self::$dispatching = true;
self::process_buffers();
self::$dispatching = false;
}
/**
* Notification from DML layer.
* @internal to be used from DML layer only.
*/
public static function database_transaction_commited() {
if (self::$dispatching or empty(self::$extbuffer)) {
return;
}
self::$dispatching = true;
self::process_buffers();
self::$dispatching = false;
}
/**
* Notification from DML layer.
* @internal to be used from DML layer only.
*/
public static function database_transaction_rolledback() {
self::$extbuffer = array();
}
protected static function process_buffers() {
global $DB, $CFG;
self::init_all_observers();
while (self::$buffer or self::$extbuffer) {
$fromextbuffer = false;
$addedtoextbuffer = false;
if (self::$extbuffer and !$DB->is_transaction_started()) {
$fromextbuffer = true;
$event = reset(self::$extbuffer);
unset(self::$extbuffer[key(self::$extbuffer)]);
} else if (self::$buffer) {
$event = reset(self::$buffer);
unset(self::$buffer[key(self::$buffer)]);
} else {
return;
}
$observingclasses = self::get_observing_classes($event);
foreach ($observingclasses as $observingclass) {
if (!isset(self::$allobservers[$observingclass])) {
continue;
}
foreach (self::$allobservers[$observingclass] as $observer) {
if ($observer->internal) {
if ($fromextbuffer) {
// Do not send buffered external events to internal handlers,
// they processed them already.
continue;
}
} else {
if ($DB->is_transaction_started()) {
if ($fromextbuffer) {
// Weird!
continue;
}
// Do not notify external observers while in DB transaction.
if (!$addedtoextbuffer) {
self::$extbuffer[] = $event;
$addedtoextbuffer = true;
}
continue;
}
}
if (isset($observer->includefile) and file_exists($observer->includefile)) {
include_once($observer->includefile);
}
if (is_callable($observer->callable)) {
try {
call_user_func($observer->callable, $event);
} catch (\Exception $e) {
// Observers are notified before installation and upgrade, this may throw errors.
if (empty($CFG->upgraderunning)) {
// Ignore errors during upgrade, otherwise warn developers.
debugging("Exception encountered in event observer '$observer->callable': ".$e->getMessage(), DEBUG_DEVELOPER, $e->getTrace());
}
}
} else {
debugging("Can not execute event observer '$observer->callable'");
}
}
}
// TODO: Invent some infinite loop protection in case events cross-trigger one another.
}
}
/**
* Returns list of classes related to this event.
* @param \core\event\base $event
* @return array
*/
protected static function get_observing_classes(\core\event\base $event) {
$classname = get_class($event);
$observers = array('\\'.$classname);
while ($classname = get_parent_class($classname)) {
$observers[] = '\\'.$classname;
}
$observers = array_reverse($observers, false);
return $observers;
}
/**
* Initialise the list of observers.
*/
protected static function init_all_observers() {
global $CFG;
if (is_array(self::$allobservers)) {
return;
}
if (!PHPUNIT_TEST and !during_initial_install()) {
$cache = \cache::make('core', 'observers');
$cached = $cache->get('all');
$dirroot = $cache->get('dirroot');
if ($dirroot === $CFG->dirroot and is_array($cached)) {
self::$allobservers = $cached;
return;
}
}
self::$allobservers = array();
$plugintypes = \core_component::get_plugin_types();
$plugintypes = array_merge(array('core' => 'not used'), $plugintypes);
$systemdone = false;
foreach ($plugintypes as $plugintype => $ignored) {
if ($plugintype === 'core') {
$plugins['core'] = "$CFG->dirroot/lib";
} else {
$plugins = \core_component::get_plugin_list($plugintype);
}
foreach ($plugins as $plugin => $fulldir) {
if (!file_exists("$fulldir/db/events.php")) {
continue;
}
$observers = null;
include("$fulldir/db/events.php");
if (!is_array($observers)) {
continue;
}
self::add_observers($observers, "$fulldir/db/events.php", $plugintype, $plugin);
}
}
self::order_all_observers();
if (!PHPUNIT_TEST and !during_initial_install()) {
$cache->set('all', self::$allobservers);
$cache->set('dirroot', $CFG->dirroot);
}
}
/**
* Add observers.
* @param array $observers
* @param string $file
* @param string $plugintype Plugin type of the observer.
* @param string $plugin Plugin of the observer.
*/
protected static function add_observers(array $observers, $file, $plugintype = null, $plugin = null) {
global $CFG;
foreach ($observers as $observer) {
if (empty($observer['eventname']) or !is_string($observer['eventname'])) {
debugging("Invalid 'eventname' detected in $file observer definition", DEBUG_DEVELOPER);
continue;
}
if ($observer['eventname'] === '*') {
$observer['eventname'] = '\core\event\base';
}
if (strpos($observer['eventname'], '\\') !== 0) {
$observer['eventname'] = '\\'.$observer['eventname'];
}
if (empty($observer['callback'])) {
debugging("Invalid 'callback' detected in $file observer definition", DEBUG_DEVELOPER);
continue;
}
$o = new \stdClass();
$o->callable = $observer['callback'];
if (!isset($observer['priority'])) {
$o->priority = 0;
} else {
$o->priority = (int)$observer['priority'];
}
if (!isset($observer['internal'])) {
$o->internal = true;
} else {
$o->internal = (bool)$observer['internal'];
}
if (empty($observer['includefile'])) {
$o->includefile = null;
} else {
if ($CFG->admin !== 'admin' and strpos($observer['includefile'], '/admin/') === 0) {
$observer['includefile'] = preg_replace('|^/admin/|', '/'.$CFG->admin.'/', $observer['includefile']);
}
$observer['includefile'] = $CFG->dirroot . '/' . ltrim($observer['includefile'], '/');
if (!file_exists($observer['includefile'])) {
debugging("Invalid 'includefile' detected in $file observer definition", DEBUG_DEVELOPER);
continue;
}
$o->includefile = $observer['includefile'];
}
$o->plugintype = $plugintype;
$o->plugin = $plugin;
self::$allobservers[$observer['eventname']][] = $o;
}
}
/**
* Reorder observers to allow quick lookup of observer for each event.
*/
protected static function order_all_observers() {
foreach (self::$allobservers as $classname => $observers) {
\core_collator::asort_objects_by_property($observers, 'priority', \core_collator::SORT_NUMERIC);
self::$allobservers[$classname] = array_reverse($observers);
}
}
/**
* Returns all observers in the system. This is only for use for reporting on the list of observers in the system.
*
* @access private
* @return array An array of stdClass with all core observer details.
*/
public static function get_all_observers() {
self::init_all_observers();
return self::$allobservers;
}
/**
* Replace all standard observers.
* @param array $observers
* @return array
*
* @throws \coding_Exception if used outside of unit tests.
*/
public static function phpunit_replace_observers(array $observers) {
if (!PHPUNIT_TEST) {
throw new \coding_exception('Cannot override event observers outside of phpunit tests!');
}
self::phpunit_reset();
self::$allobservers = array();
self::$reloadaftertest = true;
self::add_observers($observers, 'phpunit');
self::order_all_observers();
return self::$allobservers;
}
/**
* Reset everything if necessary.
* @private
*
* @throws \coding_Exception if used outside of unit tests.
*/
public static function phpunit_reset() {
if (!PHPUNIT_TEST) {
throw new \coding_exception('Cannot reset event manager outside of phpunit tests!');
}
self::$buffer = array();
self::$extbuffer = array();
self::$dispatching = false;
if (!self::$reloadaftertest) {
self::$allobservers = null;
}
self::$reloadaftertest = false;
}
}