*
Faster instantiation of the event dispatcher service
*
* Instead of calling addSubscriberService
once for each
* subscriber, a precompiled array of listener definitions is passed
* directly to the constructor. This is faster by roughly an order of
* magnitude. The listeners are collected and prepared using a compiler
* pass.
*
* Lazy instantiation of listeners
*
* Services are only retrieved from the container just before invocation.
* Especially when dispatching the KernelEvents::REQUEST event, this leads
* to a more timely invocation of the first listener. Overall dispatch
* runtime is not affected by this change though.
*
*
*/
class ContainerAwareEventDispatcher implements EventDispatcherInterface {
/**
* The service container.
*
* @var \Symfony\Component\DependencyInjection\ContainerInterface;
*/
protected $container;
/**
* Listener definitions.
*
* A nested array of listener definitions keyed by event name and priority.
* A listener definition is an associative array with one of the following key
* value pairs:
* - callable: A callable listener
* - service: An array of the form [service id, method]
*
* A service entry will be resolved to a callable only just before its
* invocation.
*
* @var array
*/
protected $listeners;
/**
* Whether listeners need to be sorted prior to dispatch, keyed by event name.
*
* @var TRUE[]
*/
protected $unsorted;
/**
* Constructs a container aware event dispatcher.
*
* @param \Symfony\Component\DependencyInjection\ContainerInterface $container
* The service container.
* @param array $listeners
* A nested array of listener definitions keyed by event name and priority.
* The array is expected to be ordered by priority. A listener definition is
* an associative array with one of the following key value pairs:
* - callable: A callable listener
* - service: An array of the form [service id, method]
* A service entry will be resolved to a callable only just before its
* invocation.
*/
public function __construct(ContainerInterface $container, array $listeners = []) {
$this->container = $container;
$this->listeners = $listeners;
$this->unsorted = [];
}
/**
* {@inheritdoc}
*/
public function dispatch($event_name, Event $event = NULL) {
if ($event === NULL) {
$event = new Event();
}
if (isset($this->listeners[$event_name])) {
// Sort listeners if necessary.
if (isset($this->unsorted[$event_name])) {
krsort($this->listeners[$event_name]);
unset($this->unsorted[$event_name]);
}
// Invoke listeners and resolve callables if necessary.
foreach ($this->listeners[$event_name] as $priority => &$definitions) {
foreach ($definitions as $key => &$definition) {
if (!isset($definition['callable'])) {
$definition['callable'] = [$this->container->get($definition['service'][0]), $definition['service'][1]];
}
if (is_array($definition['callable']) && isset($definition['callable'][0]) && $definition['callable'][0] instanceof \Closure) {
$definition['callable'][0] = $definition['callable'][0]();
}
call_user_func($definition['callable'], $event, $event_name, $this);
if ($event->isPropagationStopped()) {
return $event;
}
}
}
}
return $event;
}
/**
* {@inheritdoc}
*/
public function getListeners($event_name = NULL) {
$result = [];
if ($event_name === NULL) {
// If event name was omitted, collect all listeners of all events.
foreach (array_keys($this->listeners) as $event_name) {
$listeners = $this->getListeners($event_name);
if (!empty($listeners)) {
$result[$event_name] = $listeners;
}
}
}
elseif (isset($this->listeners[$event_name])) {
// Sort listeners if necessary.
if (isset($this->unsorted[$event_name])) {
krsort($this->listeners[$event_name]);
unset($this->unsorted[$event_name]);
}
// Collect listeners and resolve callables if necessary.
foreach ($this->listeners[$event_name] as $priority => &$definitions) {
foreach ($definitions as $key => &$definition) {
if (!isset($definition['callable'])) {
$definition['callable'] = [$this->container->get($definition['service'][0]), $definition['service'][1]];
}
if (is_array($definition['callable']) && isset($definition['callable'][0]) && $definition['callable'][0] instanceof \Closure) {
$definition['callable'][0] = $definition['callable'][0]();
}
$result[] = $definition['callable'];
}
}
}
return $result;
}
/**
* {@inheritdoc}
*/
public function getListenerPriority($event_name, $listener) {
if (!isset($this->listeners[$event_name])) {
return;
}
if (is_array($listener) && isset($listener[0]) && $listener[0] instanceof \Closure) {
$listener[0] = $listener[0]();
}
// Resolve service definitions if the listener has not been found so far.
foreach ($this->listeners[$event_name] as $priority => &$definitions) {
foreach ($definitions as $key => &$definition) {
if (!isset($definition['callable'])) {
// Once the callable is retrieved we keep it for subsequent method
// invocations on this class.
$definition['callable'] = [
$this->container->get($definition['service'][0]),
$definition['service'][1],
];
}
if (is_array($definition['callable']) && isset($definition['callable'][0]) && $definition['callable'][0] instanceof \Closure) {
$definition['callable'][0] = $definition['callable'][0]();
}
if ($definition['callable'] === $listener) {
return $priority;
}
}
}
}
/**
* {@inheritdoc}
*/
public function hasListeners($event_name = NULL) {
if ($event_name !== NULL) {
return !empty($this->listeners[$event_name]);
}
foreach ($this->listeners as $event_listeners) {
if ($event_listeners) {
return TRUE;
}
}
return FALSE;
}
/**
* {@inheritdoc}
*/
public function addListener($event_name, $listener, $priority = 0) {
$this->listeners[$event_name][$priority][] = ['callable' => $listener];
$this->unsorted[$event_name] = TRUE;
}
/**
* {@inheritdoc}
*/
public function removeListener($event_name, $listener) {
if (!isset($this->listeners[$event_name])) {
return;
}
foreach ($this->listeners[$event_name] as $priority => $definitions) {
foreach ($definitions as $key => $definition) {
if (!isset($definition['callable'])) {
if (!$this->container->initialized($definition['service'][0])) {
continue;
}
$definition['callable'] = [$this->container->get($definition['service'][0]), $definition['service'][1]];
}
if (is_array($definition['callable']) && isset($definition['callable'][0]) && $definition['callable'][0] instanceof \Closure && !$listener instanceof \Closure) {
$definition['callable'][0] = $definition['callable'][0]();
}
if (is_array($definition['callable']) && isset($definition['callable'][0]) && !$definition['callable'][0] instanceof \Closure && is_array($listener) && isset($listener[0]) && $listener[0] instanceof \Closure) {
$listener[0] = $listener[0]();
}
if ($definition['callable'] === $listener) {
unset($definitions[$key]);
}
}
if ($definitions) {
$this->listeners[$event_name][$priority] = $definitions;
}
else {
unset($this->listeners[$event_name][$priority]);
}
}
}
/**
* {@inheritdoc}
*/
public function addSubscriber(EventSubscriberInterface $subscriber) {
foreach ($subscriber->getSubscribedEvents() as $event_name => $params) {
if (is_string($params)) {
$this->addListener($event_name, [$subscriber, $params]);
}
elseif (is_string($params[0])) {
$this->addListener($event_name, [$subscriber, $params[0]], isset($params[1]) ? $params[1] : 0);
}
else {
foreach ($params as $listener) {
$this->addListener($event_name, [$subscriber, $listener[0]], isset($listener[1]) ? $listener[1] : 0);
}
}
}
}
/**
* {@inheritdoc}
*/
public function removeSubscriber(EventSubscriberInterface $subscriber) {
foreach ($subscriber->getSubscribedEvents() as $event_name => $params) {
if (is_array($params) && is_array($params[0])) {
foreach ($params as $listener) {
$this->removeListener($event_name, [$subscriber, $listener[0]]);
}
}
else {
$this->removeListener($event_name, [$subscriber, is_string($params) ? $params : $params[0]]);
}
}
}
}