event-dispatcher: after-events hooks to get the trigger event info

after-events hooks will get the original event triggering it, instead of the
rescan event.

after-events hook can register with any event, but it is called with rescan event
info. This is so because, after-events hook run after all the on-events hooks
are done with and as a part of the rescan event. so it is triggered with rescan
event data, which doesnt carry much info, instead of rescan event, it makes more
sense to call the after-events hook with the original event which triggered it.

lib/wp/event-dispatcher.c

@@ -200,6 +200,7 @@ void
 wp_event_stop_processing (WpEvent * self)
 {
   g_return_if_fail (self != NULL);
+  wp_debug ("stopping event(%s)", self->name);
   g_cancellable_cancel (self->cancellable);
 }
 
@@ -250,6 +251,9 @@ on_event_hook_done (WpEventHook * hook, GAsyncResult * res, WpEvent * event)
       error->domain != G_IO_ERROR && error->code != G_IO_ERROR_CANCELLED)
     wp_message_object (hook, "failed: %s", error->message);
 
+  if (dispatcher->rescan_event == event)
+    wp_event_hook_set_event (event->current_hook_in_async, NULL);
+
   g_clear_object (&event->current_hook_in_async);
   spa_system_eventfd_write (dispatcher->system, dispatcher->eventfd, 1);
 }
@@ -284,8 +288,10 @@ wp_event_source_dispatch (GSource * s, GSourceFunc callback, gpointer user_data)
       return G_SOURCE_CONTINUE;
 
     /* remove the remaining hooks if the event was cancelled */
-    if (g_cancellable_is_cancelled (event->cancellable) && event->hooks)
+    if (g_cancellable_is_cancelled (event->cancellable) && event->hooks) {
+      wp_debug_object (d, "event(%s) cancelled remove it", event->name);
       g_list_free_full (g_steal_pointer (&event->hooks), g_object_unref);
+    }
 
     /* avoid duplicate entries in chain */
     if (!d->events_chain || !strstr (d->events_chain, event->name)) {
@@ -300,6 +306,7 @@ wp_event_source_dispatch (GSource * s, GSourceFunc callback, gpointer user_data)
     if (lhook) {
       gchar *name = NULL;
       gint priority;
+
       event->current_hook_in_async = WP_EVENT_HOOK (lhook->data);
       event->hooks = g_list_delete_link (event->hooks, g_steal_pointer (&lhook));
       name = wp_event_hook_get_name (event->current_hook_in_async);
@@ -309,8 +316,22 @@ wp_event_source_dispatch (GSource * s, GSourceFunc callback, gpointer user_data)
       wp_debug_object (d, "running hook <%p>(%s) and hooks chain (%s)",
         event->current_hook_in_async, name, event->hooks_chain);
 
-      /* execute the hook, possibly async */
+      if (event == d->rescan_event) {
-      wp_event_hook_run (event->current_hook_in_async, event,
+        WpEvent *hook_event =
+          wp_event_hook_get_event (event->current_hook_in_async);
+
+        /* for after-events, check if the corresponding event is cancelled */
+        if (g_cancellable_is_cancelled (hook_event->cancellable))
+          wp_debug_object (d, "remove hook(%s) as its trigger event(%s)"
+            " is cancelled", name, hook_event->name);
+        else
+          wp_event_hook_run (event->current_hook_in_async, hook_event,
+            event->cancellable, (GAsyncReadyCallback) on_event_hook_done,
+            event);
+      }
+      else
+        /* execute the hook, possibly async */
+        wp_event_hook_run (event->current_hook_in_async, event,
           event->cancellable, (GAsyncReadyCallback) on_event_hook_done, event);
     }
 
@@ -480,7 +501,9 @@ wp_event_dispatcher_push_event (WpEventDispatcher * self, WpEvent * event)
             self->rescan_event->hooks, g_object_ref (hook),
             (GCompareFunc) hook_cmp_func);
         wp_debug_object (self, "added rescan hook <%p>(%s(%d))", hook,
-          wp_event_hook_get_name (hook), wp_event_hook_get_priority (hook));
+            wp_event_hook_get_name (hook), wp_event_hook_get_priority (hook));
+
+        wp_event_hook_set_event (hook, event);
         rescan_hooks_added = true;
       }
     }

lib/wp/event-hook.c

@@ -21,6 +21,8 @@ struct _WpEventHookPrivate
   WpEventHookExecType exec_type;
   GWeakRef dispatcher;
   gchar *name;
+  /* event triggering the hook, useful for after-events. */
+  WpEvent *event_trigger;
 };
 
 enum {
@@ -47,6 +49,7 @@ wp_event_hook_finalize (GObject * object)
   WpEventHookPrivate *priv = wp_event_hook_get_instance_private (self);
 
   g_weak_ref_clear (&priv->dispatcher);
+  g_clear_pointer (&priv->event_trigger, wp_event_unref);
   g_free (priv->name);
 
   G_OBJECT_CLASS (wp_event_hook_parent_class)->finalize (object);
@@ -130,6 +133,38 @@ wp_event_hook_class_init (WpEventHookClass * klass)
           G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));
 }
 
+/*!
+ * \brief Returns the event triggering the hook, this data is useful for
+ * after-events.
+ *
+ * \ingroup wpeventhook
+ * \param self the event hook
+ * \returns (transfer none) (nullable): the event
+ */
+WpEvent *
+wp_event_hook_get_event (WpEventHook *self)
+{
+  g_return_val_if_fail (WP_IS_EVENT_HOOK (self), 0);
+  WpEventHookPrivate *priv = wp_event_hook_get_instance_private (self);
+  return priv->event_trigger;
+}
+
+/*!
+ * \brief Sets the event triggering the hook
+ *
+ * \ingroup wpeventhook
+ * \param self the event hook
+ * \param event (transfer none) (nullable):the event associated with the hook
+ */
+void
+wp_event_hook_set_event (WpEventHook *self, WpEvent *event)
+{
+  WpEventHookPrivate *priv = wp_event_hook_get_instance_private (self);
+  g_clear_pointer (&priv->event_trigger, wp_event_unref);
+  if (event)
+    priv->event_trigger = wp_event_ref (event);
+}
+
 /*!
  * \brief Returns the priority of the hook
  *
@@ -191,6 +226,14 @@ wp_event_hook_get_dispatcher (WpEventHook * self)
   return g_weak_ref_get (&priv->dispatcher);
 }
 
+/*!
+ * \brief Sets the dispatcher to the hook
+ *
+ * \ingroup wpeventhook
+ * \param self the event hook
+ * \param dispatcher (transfer none) (nullable) dispatcher to which the hook is
+ *  to be registered.
+ */
 void
 wp_event_hook_set_dispatcher (WpEventHook * self, WpEventDispatcher * dispatcher)
 {

lib/wp/event-hook.h

@@ -29,8 +29,15 @@ typedef enum
 {
   WP_EVENT_HOOK_DEFAULT_PRIORITY_BASE = 0,
 
-  WP_EVENT_HOOK_DEFAULT_PRIORITY_RESCAN_POLICY = WP_EVENT_HOOK_DEFAULT_PRIORITY_BASE,
+  WP_EVENT_HOOK_DEFAULT_PRIORITY_FIND_DEFINED_TARGET = WP_EVENT_HOOK_DEFAULT_PRIORITY_BASE,
-  WP_EVENT_HOOK_DEFAULT_PRIORITY_AFTER_EVENTS_DEFAULT_NODES_STATE_SAVE = WP_EVENT_HOOK_DEFAULT_PRIORITY_RESCAN_POLICY + PRIORITY_STEP, WP_EVENT_HOOK_DEFAULT_PRIORITY_RESCAN_DEFAULT_NODES = WP_EVENT_HOOK_DEFAULT_PRIORITY_AFTER_EVENTS_DEFAULT_NODES_STATE_SAVE + PRIORITY_STEP,
+  WP_EVENT_HOOK_DEFAULT_PRIORITY_FIND_UNDEFINED_TARGET = WP_EVENT_HOOK_DEFAULT_PRIORITY_FIND_DEFINED_TARGET + PRIORITY_STEP,
+  WP_EVENT_HOOK_DEFAULT_PRIORITY_FIND_BEST_TARGET = WP_EVENT_HOOK_DEFAULT_PRIORITY_FIND_UNDEFINED_TARGET + PRIORITY_STEP,
+  WP_EVENT_HOOK_DEFAULT_PRIORITY_PREPARE_LINK = WP_EVENT_HOOK_DEFAULT_PRIORITY_FIND_BEST_TARGET + PRIORITY_STEP,
+  WP_EVENT_HOOK_DEFAULT_PRIORITY_CREATE_LINK = WP_EVENT_HOOK_DEFAULT_PRIORITY_PREPARE_LINK + PRIORITY_STEP,
+
+  WP_EVENT_HOOK_DEFAULT_PRIORITY_RESCAN_POLICY = WP_EVENT_HOOK_DEFAULT_PRIORITY_CREATE_LINK + PRIORITY_STEP,
+  WP_EVENT_HOOK_DEFAULT_PRIORITY_AFTER_EVENTS_DEFAULT_NODES_STATE_SAVE = WP_EVENT_HOOK_DEFAULT_PRIORITY_RESCAN_POLICY + PRIORITY_STEP,
+  WP_EVENT_HOOK_DEFAULT_PRIORITY_RESCAN_DEFAULT_NODES = WP_EVENT_HOOK_DEFAULT_PRIORITY_AFTER_EVENTS_DEFAULT_NODES_STATE_SAVE + PRIORITY_STEP,
 
   WP_EVENT_HOOK_DEFAULT_PRIORITY_NODE_ADDED = WP_EVENT_HOOK_DEFAULT_PRIORITY_RESCAN_POLICY + PRIORITY_JUMP,
   WP_EVENT_HOOK_DEFAULT_PRIORITY_NODE_ADDED_RESTORE_STREAM = WP_EVENT_HOOK_DEFAULT_PRIORITY_NODE_ADDED,
@@ -120,6 +127,12 @@ WP_PRIVATE_API
 void wp_event_hook_set_dispatcher (WpEventHook * self,
     WpEventDispatcher * dispatcher);
 
+WP_API
+void wp_event_hook_set_event (WpEventHook *self, WpEvent *event);
+
+WP_API
+WpEvent *wp_event_hook_get_event (WpEventHook *self);
+
 WP_API
 gboolean wp_event_hook_runs_for_event (WpEventHook * self, WpEvent * event);
 

tests/wp/events.c

@@ -12,6 +12,7 @@ typedef struct {
   WpBaseTestFixture base;
   WpObjectManager *om;
   GPtrArray *hooks_executed;
+  GPtrArray *events;
   WpTransition *transition;
 } TestFixture;
 
@@ -20,6 +21,7 @@ test_events_setup (TestFixture *self, gconstpointer user_data)
 {
   wp_base_test_fixture_setup (&self->base, 0);
   self->hooks_executed = g_ptr_array_new ();
+  self->events = g_ptr_array_new ();
 }
 
 static void
@@ -35,6 +37,7 @@ test_events_teardown (TestFixture *self, gconstpointer user_data)
   { \
     g_debug ("in hook_" #x); \
     g_ptr_array_add (self->hooks_executed, hook_##x); \
+    g_ptr_array_add (self->events, event); \
   }
 
 HOOK_FUNC(a)
@@ -47,6 +50,7 @@ hook_quit (WpEvent * event, TestFixture * self)
 {
   g_debug ("in hook_quit");
   g_ptr_array_add (self->hooks_executed, hook_quit);
+  g_ptr_array_add (self->events, event);
   g_main_loop_quit (self->base.loop);
 }
 
@@ -55,6 +59,7 @@ test_events_basic (TestFixture * self, gconstpointer user_data)
 {
   g_autoptr (WpEventDispatcher) dispatcher = NULL;
   g_autoptr (WpEventHook) hook = NULL;
+  WpEvent *event1 = NULL, *event2 = NULL;
 
   dispatcher = wp_event_dispatcher_get_instance (self->base.core);
   g_assert_nonnull (dispatcher);
@@ -101,37 +106,73 @@ test_events_basic (TestFixture * self, gconstpointer user_data)
   wp_event_dispatcher_register_hook (dispatcher, hook);
   g_clear_object (&hook);
 
-  /* first event */
+  /* first event run */
-  wp_event_dispatcher_push_event (dispatcher,
+  event1 = wp_event_new ("type1", 10, NULL, NULL, NULL);
-      wp_event_new ("type1", 10, NULL, NULL, NULL));
+  wp_event_dispatcher_push_event (dispatcher, event1);
 
   g_assert_cmpint (self->hooks_executed->len, ==, 0);
   g_main_loop_run (self->base.loop);
   g_assert_cmpint (self->hooks_executed->len, ==, 4);
   g_assert (hook_c == self->hooks_executed->pdata[0]);
+  g_assert (event1 == self->events->pdata[0]);
   g_assert (hook_a == self->hooks_executed->pdata[1]);
-  g_assert (hook_b == self->hooks_executed->pdata[2]);
+  g_assert (event1 == self->events->pdata [1]);
-  g_assert (hook_quit == self->hooks_executed->pdata[3]);
+  g_assert (hook_b == self->hooks_executed->pdata [2]);
+  g_assert (event1 == self->events->pdata [2]);
+  g_assert (hook_quit == self->hooks_executed->pdata [3]);
+  g_assert (event1 == self->events->pdata [3]);
 
   g_ptr_array_remove_range (self->hooks_executed, 0, self->hooks_executed->len);
   g_assert_cmpint (self->hooks_executed->len, ==, 0);
+  g_ptr_array_remove_range (self->events, 0, self->events->len);
+  g_assert_cmpint (self->events->len, == , 0);
 
-  /* second event */
+  /* second event run */
-  wp_event_dispatcher_push_event (dispatcher,
+  event1 = wp_event_new ("type1", 10,
-      wp_event_new ("type1", 10,
+    wp_properties_new ("test.prop", "some-val", NULL), NULL, NULL);
-          wp_properties_new ("test.prop", "some-val", NULL), NULL, NULL));
+  event2 = wp_event_new ("type2", 100,
-  wp_event_dispatcher_push_event (dispatcher,
+      wp_properties_new ("test.prop", "some-val", NULL), NULL, NULL);
-      wp_event_new ("type2", 100,
+
-          wp_properties_new ("test.prop", "some-val", NULL), NULL, NULL));
+  wp_event_dispatcher_push_event (dispatcher, event1);
+  wp_event_dispatcher_push_event (dispatcher, event2);
 
   g_assert_cmpint (self->hooks_executed->len, ==, 0);
   g_main_loop_run (self->base.loop);
   g_assert_cmpint (self->hooks_executed->len, ==, 5);
-  g_assert (hook_d == self->hooks_executed->pdata[0]);
+  g_assert (hook_d == self->hooks_executed->pdata [0]);
-  g_assert (hook_c == self->hooks_executed->pdata[1]);
+  g_assert (event2 == self->events->pdata [0]);
-  g_assert (hook_a == self->hooks_executed->pdata[2]);
+  g_assert (hook_c == self->hooks_executed->pdata [1]);
-  g_assert (hook_b == self->hooks_executed->pdata[3]);
+  g_assert (event1 == self->events->pdata [1]);
-  g_assert (hook_quit == self->hooks_executed->pdata[4]);
+  g_assert (hook_a == self->hooks_executed->pdata [2]);
+  g_assert (event1 == self->events->pdata [2]);
+  g_assert (hook_b == self->hooks_executed->pdata [3]);
+  g_assert (event1 == self->events->pdata [3]);
+  g_assert (hook_quit == self->hooks_executed->pdata [4]);
+  g_assert (event1 == self->events->pdata [4]);
+
+  g_ptr_array_remove_range (self->hooks_executed, 0, self->hooks_executed->len);
+  g_assert_cmpint (self->hooks_executed->len, == , 0);
+  g_ptr_array_remove_range (self->events, 0, self->events->len);
+  g_assert_cmpint (self->events->len, == , 0);
+
+
+  /* thrid event run to test event cancellation */
+  event1 = wp_event_new ("type1", 10,
+    wp_properties_new ("test.prop", "some-val", NULL), NULL, NULL);
+  event2 = wp_event_new ("type2", 100,
+    wp_properties_new ("test.prop", "some-val", NULL), NULL, NULL);
+
+  wp_event_dispatcher_push_event (dispatcher, event2);
+  wp_event_dispatcher_push_event (dispatcher, event1);
+  wp_event_stop_processing (event1);
+
+  g_assert_cmpint (self->hooks_executed->len, == , 0);
+  g_main_loop_run (self->base.loop);
+  g_assert_cmpint (self->hooks_executed->len, == , 2);
+  g_assert (hook_d == self->hooks_executed->pdata [0]);
+  g_assert (event2 == self->events->pdata [0]);
+  g_assert (hook_quit == self->hooks_executed->pdata [1]);
+  g_assert (event2 == self->events->pdata [1]);
 }
 
 enum {