/**
* Collects services to add/inject them into a consumer service.
*
- * This mechanism allows a service to get multiple processor services injected,
- * in order to establish an extensible architecture.
+ * This mechanism allows a service to get multiple processor services or just
+ * their IDs injected, in order to establish an extensible architecture.
*
- * It differs from the factory pattern in that processors are not lazily
- * instantiated on demand; the consuming service receives instances of all
- * registered processors when it is instantiated. Unlike a factory service, the
- * consuming service is not ContainerAware.
+ * The service collector differs from the factory pattern in that processors are
+ * not lazily instantiated on demand; the consuming service receives instances
+ * of all registered processors when it is instantiated. Unlike a factory
+ * service, the consuming service is not ContainerAware. It differs from regular
+ * service definition arguments (constructor injection) in that a consuming
+ * service MAY allow further processors to be added dynamically at runtime. This
+ * is why the called method (optionally) receives the priority of a processor as
+ * second argument.
*
- * It differs from plugins in that all processors are explicitly registered by
+ * To lazily instantiate services the service ID collector pattern can be used,
+ * but the consumer service needs to also inject the 'class_resolver' service.
+ * As constructor injection is used, processors cannot be added at runtime via
+ * this method. However, a consuming service could have setter methods to allow
+ * runtime additions.
+ *
+ * These differ from plugins in that all processors are explicitly registered by
* service providers (driven by declarative configuration in code); the mere
* availability of a processor (cf. plugin discovery) does not imply that a
* processor ought to be registered and used.
*
- * It differs from regular service definition arguments (constructor injection)
- * in that a consuming service MAY allow further processors to be added
- * dynamically at runtime. This is why the called method (optionally) receives
- * the priority of a processor as second argument.
- *
* @see \Drupal\Core\DependencyInjection\Compiler\TaggedHandlersPass::process()
*/
class TaggedHandlersPass implements CompilerPassInterface {
/**
* {@inheritdoc}
*
- * Finds services tagged with 'service_collector', then finds all
- * corresponding tagged services and adds a method call for each to the
+ * Finds services tagged with 'service_collector' or 'service_id_collector',
+ * then finds all corresponding tagged services.
+ *
+ * The service collector adds a method call for each to the
* consuming/collecting service definition.
*
- * Supported 'service_collector' tag attributes:
+ * The service ID collector will collect an array of service IDs and add them
+ * as a constructor argument.
+ *
+ * Supported tag attributes:
* - tag: The tag name used by handler services to collect. Defaults to the
* service ID of the consumer.
- * - call: The method name to call on the consumer service. Defaults to
- * 'addHandler'. The called method receives two arguments:
- * - The handler instance as first argument.
- * - Optionally the handler's priority as second argument, if the method
- * accepts a second parameter and its name is "priority". In any case, all
- * handlers registered at compile time are sorted already.
* - required: Boolean indicating if at least one handler service is required.
* Defaults to FALSE.
*
+ * Additional tag attributes supported by 'service_collector' only:
+ * - call: The method name to call on the consumer service. Defaults to
+ * 'addHandler'. The called method receives two arguments:
+ * - The handler instance as first argument.
+ * - Optionally the handler's priority as second argument, if the method
+ * accepts a second parameter and its name is "priority". In any case,
+ * all handlers registered at compile time are sorted already.
+ *
* Example (YAML):
* @code
* tags:
* - { name: service_collector, tag: breadcrumb_builder, call: addBuilder }
+ * - { name: service_id_collector, tag: theme_negotiator }
* @endcode
*
* Supported handler tag attributes:
* If at least one tagged service is required but none are found.
*/
public function process(ContainerBuilder $container) {
- foreach ($container->findTaggedServiceIds('service_collector') as $consumer_id => $passes) {
- foreach ($passes as $pass) {
- $interface = NULL;
- $tag = isset($pass['tag']) ? $pass['tag'] : $consumer_id;
- $method_name = isset($pass['call']) ? $pass['call'] : 'addHandler';
- $required = isset($pass['required']) ? $pass['required'] : FALSE;
-
- // Determine parameters.
- $consumer = $container->getDefinition($consumer_id);
- $method = new \ReflectionMethod($consumer->getClass(), $method_name);
- $params = $method->getParameters();
-
- $interface_pos = 0;
- $id_pos = NULL;
- $priority_pos = NULL;
- $extra_params = [];
- foreach ($params as $pos => $param) {
- if ($param->getClass()) {
- $interface = $param->getClass();
- }
- elseif ($param->getName() === 'id') {
- $id_pos = $pos;
- }
- elseif ($param->getName() === 'priority') {
- $priority_pos = $pos;
- }
- else {
- $extra_params[$param->getName()] = $pos;
- }
- }
- // Determine the ID.
-
- if (!isset($interface)) {
- throw new LogicException(vsprintf("Service consumer '%s' class method %s::%s() has to type-hint an interface.", [
- $consumer_id,
- $consumer->getClass(),
- $method_name,
- ]));
+ // Avoid using ContainerBuilder::findTaggedServiceIds() as that we result in
+ // additional iterations around all the service definitions.
+ foreach ($container->getDefinitions() as $consumer_id => $definition) {
+ $tags = $definition->getTags();
+ if (isset($tags['service_collector'])) {
+ foreach ($tags['service_collector'] as $pass) {
+ $this->processServiceCollectorPass($pass, $consumer_id, $container);
}
- $interface = $interface->getName();
-
- // Find all tagged handlers.
- $handlers = [];
- $extra_arguments = [];
- foreach ($container->findTaggedServiceIds($tag) as $id => $attributes) {
- // Validate the interface.
- $handler = $container->getDefinition($id);
- if (!is_subclass_of($handler->getClass(), $interface)) {
- throw new LogicException("Service '$id' for consumer '$consumer_id' does not implement $interface.");
- }
- $handlers[$id] = isset($attributes[0]['priority']) ? $attributes[0]['priority'] : 0;
- // Keep track of other tagged handlers arguments.
- foreach ($extra_params as $name => $pos) {
- $extra_arguments[$id][$pos] = isset($attributes[0][$name]) ? $attributes[0][$name] : $params[$pos]->getDefaultValue();
- }
- }
- if (empty($handlers)) {
- if ($required) {
- throw new LogicException(sprintf("At least one service tagged with '%s' is required.", $tag));
- }
- continue;
- }
- // Sort all handlers by priority.
- arsort($handlers, SORT_NUMERIC);
-
- // Add a method call for each handler to the consumer service
- // definition.
- foreach ($handlers as $id => $priority) {
- $arguments = [];
- $arguments[$interface_pos] = new Reference($id);
- if (isset($priority_pos)) {
- $arguments[$priority_pos] = $priority;
- }
- if (isset($id_pos)) {
- $arguments[$id_pos] = $id;
- }
- // Add in extra arguments.
- if (isset($extra_arguments[$id])) {
- // Place extra arguments in their right positions.
- $arguments += $extra_arguments[$id];
- }
- // Sort the arguments by position.
- ksort($arguments);
- $consumer->addMethodCall($method_name, $arguments);
+ }
+ if (isset($tags['service_id_collector'])) {
+ foreach ($tags['service_id_collector'] as $pass) {
+ $this->processServiceIdCollectorPass($pass, $consumer_id, $container);
}
}
}
}
+ /**
+ * Processes a service collector service pass.
+ *
+ * @param array $pass
+ * The service collector pass data.
+ * @param string $consumer_id
+ * The consumer service ID.
+ * @param \Symfony\Component\DependencyInjection\ContainerBuilder $container
+ * The service container.
+ */
+ protected function processServiceCollectorPass(array $pass, $consumer_id, ContainerBuilder $container) {
+ $tag = isset($pass['tag']) ? $pass['tag'] : $consumer_id;
+ $method_name = isset($pass['call']) ? $pass['call'] : 'addHandler';
+ $required = isset($pass['required']) ? $pass['required'] : FALSE;
+
+ // Determine parameters.
+ $consumer = $container->getDefinition($consumer_id);
+ $method = new \ReflectionMethod($consumer->getClass(), $method_name);
+ $params = $method->getParameters();
+
+ $interface_pos = 0;
+ $id_pos = NULL;
+ $priority_pos = NULL;
+ $extra_params = [];
+ foreach ($params as $pos => $param) {
+ if ($param->getClass()) {
+ $interface = $param->getClass();
+ }
+ elseif ($param->getName() === 'id') {
+ $id_pos = $pos;
+ }
+ elseif ($param->getName() === 'priority') {
+ $priority_pos = $pos;
+ }
+ else {
+ $extra_params[$param->getName()] = $pos;
+ }
+ }
+ // Determine the ID.
+
+ if (!isset($interface)) {
+ throw new LogicException(vsprintf("Service consumer '%s' class method %s::%s() has to type-hint an interface.", [
+ $consumer_id,
+ $consumer->getClass(),
+ $method_name,
+ ]));
+ }
+ $interface = $interface->getName();
+
+ // Find all tagged handlers.
+ $handlers = [];
+ $extra_arguments = [];
+ foreach ($container->findTaggedServiceIds($tag) as $id => $attributes) {
+ // Validate the interface.
+ $handler = $container->getDefinition($id);
+ if (!is_subclass_of($handler->getClass(), $interface)) {
+ throw new LogicException("Service '$id' for consumer '$consumer_id' does not implement $interface.");
+ }
+ $handlers[$id] = isset($attributes[0]['priority']) ? $attributes[0]['priority'] : 0;
+ // Keep track of other tagged handlers arguments.
+ foreach ($extra_params as $name => $pos) {
+ $extra_arguments[$id][$pos] = isset($attributes[0][$name]) ? $attributes[0][$name] : $params[$pos]->getDefaultValue();
+ }
+ }
+
+ if ($required && empty($handlers)) {
+ throw new LogicException(sprintf("At least one service tagged with '%s' is required.", $tag));
+ }
+
+ // Sort all handlers by priority.
+ arsort($handlers, SORT_NUMERIC);
+
+ // Add a method call for each handler to the consumer service
+ // definition.
+ foreach ($handlers as $id => $priority) {
+ $arguments = [];
+ $arguments[$interface_pos] = new Reference($id);
+ if (isset($priority_pos)) {
+ $arguments[$priority_pos] = $priority;
+ }
+ if (isset($id_pos)) {
+ $arguments[$id_pos] = $id;
+ }
+ // Add in extra arguments.
+ if (isset($extra_arguments[$id])) {
+ // Place extra arguments in their right positions.
+ $arguments += $extra_arguments[$id];
+ }
+ // Sort the arguments by position.
+ ksort($arguments);
+ $consumer->addMethodCall($method_name, $arguments);
+ }
+ }
+
+ /**
+ * Processes a service collector ID service pass.
+ *
+ * @param array $pass
+ * The service collector pass data.
+ * @param string $consumer_id
+ * The consumer service ID.
+ * @param \Symfony\Component\DependencyInjection\ContainerBuilder $container
+ * The service container.
+ */
+ protected function processServiceIdCollectorPass(array $pass, $consumer_id, ContainerBuilder $container) {
+ $tag = isset($pass['tag']) ? $pass['tag'] : $consumer_id;
+ $required = isset($pass['required']) ? $pass['required'] : FALSE;
+
+ $consumer = $container->getDefinition($consumer_id);
+
+ // Find all tagged handlers.
+ $handlers = [];
+ foreach ($container->findTaggedServiceIds($tag) as $id => $attributes) {
+ $handlers[$id] = isset($attributes[0]['priority']) ? $attributes[0]['priority'] : 0;
+ }
+
+ if ($required && empty($handlers)) {
+ throw new LogicException(sprintf("At least one service tagged with '%s' is required.", $tag));
+ }
+
+ // Sort all handlers by priority.
+ arsort($handlers, SORT_NUMERIC);
+
+ $consumer->addArgument(array_keys($handlers));
+ }
+
}