[ticket/15214] Add event & functionality for assigning template event priority

Event added to allow template events to be assigned priority per extension,
event location chosen so that it only fires once.
Twig node event class refactored to allow template event priority assignment,
compile calls are deferred until all locations are processed
per extension namespace.
Priority precedence mirrors Symfony priority, with higher numbers
being placed at the beginning of the array.
Duplicate priority assignment will currently have the later events
compiled before the others.

PHPBB3-15214

phpBB/config/default/container/services_twig.yml

@@ -40,6 +40,7 @@ services:
             - '@template_context'
             - '@template.twig.environment'
             - '@language'
+            - '@dispatcher'
         tags:
             - { name: twig.extension }
 

phpBB/phpbb/template/twig/extension.php

@@ -28,18 +28,23 @@ class extension extends \Twig\Extension\AbstractExtension
 	/** @var \phpbb\language\language */
 	protected $language;
 
+	/** @var \phpbb\event\dispatcher_interface */
+	protected $phpbb_dispatcher;
+
 	/**
 	* Constructor
 	*
 	* @param \phpbb\template\context $context
 	* @param \phpbb\template\twig\environment $environment
 	* @param \phpbb\language\language $language
+	* @param \phpbb\event\dispatcher_interface $phpbb_dispatcher
 	*/
-	public function __construct(\phpbb\template\context $context, \phpbb\template\twig\environment $environment, $language)
+	public function __construct(\phpbb\template\context $context, \phpbb\template\twig\environment $environment, $language, \phpbb\event\dispatcher_interface $phpbb_dispatcher)
 	{
 		$this->context = $context;
 		$this->environment = $environment;
 		$this->language = $language;
+		$this->phpbb_dispatcher = $phpbb_dispatcher;
 	}
 
 	/**
@@ -64,7 +69,7 @@ class extension extends \Twig\Extension\AbstractExtension
 			new \phpbb\template\twig\tokenparser\includeparser,
 			new \phpbb\template\twig\tokenparser\includejs,
 			new \phpbb\template\twig\tokenparser\includecss,
-			new \phpbb\template\twig\tokenparser\event($this->environment),
+			new \phpbb\template\twig\tokenparser\event($this->environment, $this->phpbb_dispatcher),
 		);
 	}
 

phpBB/phpbb/template/twig/node/event.php

@@ -24,9 +24,13 @@ class event extends \Twig\Node\Node
 	/** @var \phpbb\template\twig\environment */
 	protected $environment;
 
-	public function __construct(\Twig\Node\Expression\AbstractExpression $expr, \phpbb\template\twig\environment $environment, $lineno, $tag = null)
+	/** @var array */
+	protected $template_event_priority_array;
+
+	public function __construct(\Twig\Node\Expression\AbstractExpression $expr, \phpbb\template\twig\environment $environment, $lineno, $tag = null, $template_event_priority_array = [])
 	{
 		$this->environment = $environment;
+		$this->template_event_priority_array = $template_event_priority_array;
 
 		parent::__construct(array('expr' => $expr), array(), $lineno, $tag);
 	}
@@ -42,17 +46,26 @@ class event extends \Twig\Node\Node
 
 		$location = $this->listener_directory . $this->getNode('expr')->getAttribute('name');
 
+		$compiler_steps = [];
+
 		foreach ($this->environment->get_phpbb_extensions() as $ext_namespace => $ext_path)
 		{
 			$ext_namespace = str_replace('/', '_', $ext_namespace);
 
+			if (isset($this->template_event_priority_array[$ext_namespace][$location]))
+			{
+				$priority_key = $this->template_event_priority_array[$ext_namespace][$location];
+			}
+
+			$compiler_calls = [];
+
 			if ($this->environment->isDebug())
 			{
 				// If debug mode is enabled, lets check for new/removed EVENT
 				//  templates on page load rather than at compile. This is
 				//  slower, but makes developing extensions easier (no need to
 				//  purge the cache when a new event template file is added)
-				$compiler
+				$compiler_calls[] = fn() => $compiler
 					->write("if (\$this->env->getLoader()->exists('@{$ext_namespace}/{$location}.html')) {\n")
 					->indent()
 				;
@@ -60,7 +73,7 @@ class event extends \Twig\Node\Node
 
 			if ($this->environment->isDebug() || $this->environment->getLoader()->exists('@' . $ext_namespace . '/' . $location . '.html'))
 			{
-				$compiler
+				$compiler_calls[] = fn() => $compiler
 					->write("\$previous_look_up_order = \$this->env->getNamespaceLookUpOrder();\n")
 
 					// We set the namespace lookup order to be this extension first, then the main path
@@ -72,11 +85,39 @@ class event extends \Twig\Node\Node
 
 			if ($this->environment->isDebug())
 			{
-				$compiler
+				$compiler_calls[] = fn() => $compiler
 					->outdent()
 					->write("}\n\n")
 				;
 			}
+
+			if (!empty($compiler_calls))
+			{
+				if (isset($priority_key))
+				{
+					if (array_key_exists($priority_key, $compiler_steps))
+					{
+						array_splice($compiler_steps, $priority_key, 0, [$compiler_calls]);
+					}
+					else
+					{
+						$compiler_steps[$priority_key] = $compiler_calls;
+					}
+				}
+				else
+				{
+					array_unshift($compiler_steps, $compiler_calls);
+				}
+			}
+		}
+
+		krsort($compiler_steps);
+		foreach ($compiler_steps as $ext_namespace_steps)
+		{
+			foreach ($ext_namespace_steps as $step)
+			{
+				$step();
+			}
 		}
 	}
 }

phpBB/phpbb/template/twig/tokenparser/event.php

@@ -18,14 +18,38 @@ class event extends \Twig\TokenParser\AbstractTokenParser
 	/** @var \phpbb\template\twig\environment */
 	protected $environment;
 
+	/** @var \phpbb\event\dispatcher_interface */
+	protected $phpbb_dispatcher;
+
+	/** @var array */
+	protected $template_event_priority_array;
+
 	/**
 	* Constructor
 	*
 	* @param \phpbb\template\twig\environment $environment
 	*/
-	public function __construct(\phpbb\template\twig\environment $environment)
+	public function __construct(\phpbb\template\twig\environment $environment, \phpbb\event\dispatcher_interface $phpbb_dispatcher = null)
 	{
 		$this->environment = $environment;
+		$this->phpbb_dispatcher = $phpbb_dispatcher;
+
+		$template_event_priority_array = [];
+
+		/**
+		* Allow assigning priority to template events
+		*
+		* @event core.twig_tokenparser_constructor
+		* @var	array	template_event_priority_array	Array with template event priority assignments per extension namespace
+		* @since 3.3.12-RC1
+		*/
+		if ($this->phpbb_dispatcher)
+		{
+			$vars = array('template_event_priority_array');
+			extract($this->phpbb_dispatcher->trigger_event('core.twig_tokenparser_constructor', compact($vars)));
+		}
+
+		$this->template_event_priority_array = $template_event_priority_array;
 	}
 
 	/**
@@ -42,7 +66,7 @@ class event extends \Twig\TokenParser\AbstractTokenParser
 		$stream = $this->parser->getStream();
 		$stream->expect(\Twig\Token::BLOCK_END_TYPE);
 
-		return new \phpbb\template\twig\node\event($expr, $this->environment, $token->getLine(), $this->getTag());
+		return new \phpbb\template\twig\node\event($expr, $this->environment, $token->getLine(), $this->getTag(), $this->template_event_priority_array);
 	}
 
 	/**