input-device: add APIs to grab sequences of touch events

https://bugzilla.gnome.org/show_bug.cgi?id=678279

clutter/clutter-device-manager-private.h

@@ -86,6 +86,8 @@ struct _ClutterInputDevice
   /* the actor that has a grab in place for the device */
   ClutterActor *pointer_grab_actor;
   ClutterActor *keyboard_grab_actor;
+  GHashTable   *sequence_grab_actors;
+  GHashTable   *inv_sequence_grab_actors;
 
   /* the current click count */
   gint click_count;

clutter/clutter-event.h

@@ -115,16 +115,6 @@ typedef struct _ClutterStageStateEvent  ClutterStageStateEvent;
 typedef struct _ClutterCrossingEvent    ClutterCrossingEvent;
 typedef struct _ClutterTouchEvent       ClutterTouchEvent;
 
-/**
- * ClutterEventSequence:
- *
- * The <structname>ClutterEventSequence</structname> structure is an opaque
- * type used to denote the event sequence of a touch event.
- *
- * Since: 1.12
- */
-typedef struct _ClutterEventSequence    ClutterEventSequence;
-
 /**
  * ClutterAnyEvent:
  * @type: event type

clutter/clutter-input-device.c

@@ -1540,3 +1540,139 @@ _clutter_input_device_reset_scroll_info (ClutterInputDevice *device)
       info->last_value_valid = FALSE;
     }
 }
+
+static void
+on_grab_sequence_actor_destroy (ClutterActor       *actor,
+                                ClutterInputDevice *device)
+{
+  ClutterEventSequence *sequence =
+    g_hash_table_lookup (device->inv_sequence_grab_actors, actor);
+
+  if (sequence != NULL)
+    {
+      g_hash_table_remove (device->sequence_grab_actors, sequence);
+      g_hash_table_remove (device->inv_sequence_grab_actors, actor);
+    }
+}
+
+/**
+ * clutter_input_device_sequence_grab:
+ * @device: a #ClutterInputDevice
+ * @sequence: a #ClutterEventSequence
+ * @actor: a #ClutterActor
+ *
+ * Acquires a grab on @actor for the given @device and the given touch
+ * @sequence.
+ *
+ * Any touch event coming from @device and from @sequence will be
+ * delivered to @actor, bypassing the usual event delivery mechanism,
+ * until the grab is released by calling
+ * clutter_input_device_sequence_ungrab().
+ *
+ * The grab is client-side: even if the windowing system used by the Clutter
+ * backend has the concept of "device grabs", Clutter will not use them.
+ *
+ * Since: 1.12
+ */
+void
+clutter_input_device_sequence_grab (ClutterInputDevice   *device,
+                                    ClutterEventSequence *sequence,
+                                    ClutterActor         *actor)
+{
+  ClutterActor *grab_actor;
+
+  g_return_if_fail (CLUTTER_IS_INPUT_DEVICE (device));
+  g_return_if_fail (CLUTTER_IS_ACTOR (actor));
+
+  if (device->sequence_grab_actors == NULL)
+    {
+      grab_actor = NULL;
+      device->sequence_grab_actors = g_hash_table_new (NULL, NULL);
+      device->inv_sequence_grab_actors = g_hash_table_new (NULL, NULL);
+    }
+  else
+    {
+      grab_actor = g_hash_table_lookup (device->sequence_grab_actors, sequence);
+    }
+
+  if (grab_actor != NULL)
+    {
+      g_signal_handlers_disconnect_by_func (grab_actor,
+                                            G_CALLBACK (on_grab_sequence_actor_destroy),
+                                            device);
+      g_hash_table_remove (device->sequence_grab_actors, sequence);
+      g_hash_table_remove (device->inv_sequence_grab_actors, grab_actor);
+    }
+
+  g_hash_table_insert (device->sequence_grab_actors, sequence, actor);
+  g_hash_table_insert (device->inv_sequence_grab_actors, actor, sequence);
+  g_signal_connect (grab_actor,
+                    "destroy",
+                    G_CALLBACK (on_grab_sequence_actor_destroy),
+                    device);
+}
+
+/**
+ * clutter_input_device_sequence_ungrab:
+ * @device: a #ClutterInputDevice
+ * @sequence: a #ClutterEventSequence
+ *
+ * Releases the grab on the @device for the given @sequence, if one is
+ * in place.
+ *
+ * Since: 1.12
+ */
+void
+clutter_input_device_sequence_ungrab (ClutterInputDevice   *device,
+                                      ClutterEventSequence *sequence)
+{
+  ClutterActor *grab_actor;
+
+  g_return_if_fail (CLUTTER_IS_INPUT_DEVICE (device));
+
+  if (device->sequence_grab_actors == NULL)
+    return;
+
+  grab_actor = g_hash_table_lookup (device->sequence_grab_actors, sequence);
+
+  if (grab_actor == NULL)
+    return;
+
+  g_signal_handlers_disconnect_by_func (grab_actor,
+                                        G_CALLBACK (on_grab_sequence_actor_destroy),
+                                        device);
+  g_hash_table_remove (device->sequence_grab_actors, sequence);
+  g_hash_table_remove (device->inv_sequence_grab_actors, grab_actor);
+
+  if (g_hash_table_size (device->sequence_grab_actors) == 0)
+    {
+      g_hash_table_destroy (device->sequence_grab_actors);
+      device->sequence_grab_actors = NULL;
+      g_hash_table_destroy (device->inv_sequence_grab_actors);
+      device->inv_sequence_grab_actors = NULL;
+    }
+}
+
+/**
+ * clutter_input_device_sequence_get_grabbed_actor:
+ * @device: a #ClutterInputDevice
+ * @sequence: a #ClutterEventSequence
+ *
+ * Retrieves a pointer to the #ClutterActor currently grabbing the
+ * touch events coming from @device given the @sequence.
+ *
+ * Return value: (transfer none): a #ClutterActor, or %NULL
+ *
+ * Since: 1.12
+ */
+ClutterActor *
+clutter_input_device_sequence_get_grabbed_actor (ClutterInputDevice   *device,
+                                                 ClutterEventSequence *sequence)
+{
+  g_return_val_if_fail (CLUTTER_IS_INPUT_DEVICE (device), NULL);
+
+  if (device->sequence_grab_actors == NULL)
+    return NULL;
+
+  return g_hash_table_lookup (device->sequence_grab_actors, sequence);
+}

clutter/clutter-input-device.h

@@ -45,7 +45,6 @@ G_BEGIN_DECLS
  * Generic representation of an input device. The actual contents of this
  * structure depend on the backend used.
  */
-typedef struct _ClutterInputDevice      ClutterInputDevice;
 typedef struct _ClutterInputDeviceClass ClutterInputDeviceClass;
 
 GType clutter_input_device_get_type (void) G_GNUC_CONST;
@@ -97,6 +96,17 @@ void                    clutter_input_device_ungrab             (ClutterInputDev
 CLUTTER_AVAILABLE_IN_1_10
 ClutterActor *          clutter_input_device_get_grabbed_actor  (ClutterInputDevice  *device);
 
+CLUTTER_AVAILABLE_IN_1_12
+void                    clutter_input_device_sequence_grab      (ClutterInputDevice   *device,
+                                                                 ClutterEventSequence *sequence,
+                                                                 ClutterActor         *actor);
+CLUTTER_AVAILABLE_IN_1_12
+void                    clutter_input_device_sequence_ungrab    (ClutterInputDevice   *device,
+                                                                 ClutterEventSequence *sequence);
+CLUTTER_AVAILABLE_IN_1_12
+ClutterActor *          clutter_input_device_sequence_get_grabbed_actor (ClutterInputDevice   *device,
+                                                                         ClutterEventSequence *sequence);
+
 gboolean                clutter_input_device_keycode_to_evdev   (ClutterInputDevice *device,
                                                                  guint               hardware_keycode,
                                                                  guint              *evdev_keycode);

clutter/clutter-main.c

@@ -2314,6 +2314,26 @@ emit_pointer_event (ClutterEvent       *event,
     }
 }
 
+static inline void
+emit_touch_event (ClutterEvent       *event,
+                  ClutterInputDevice *device)
+{
+  ClutterActor *grab_actor;
+
+  if ((device->sequence_grab_actors != NULL) &&
+       ((grab_actor = g_hash_table_lookup (device->sequence_grab_actors,
+                                           event->touch.sequence)) != NULL))
+    {
+      /* sequence grab */
+      clutter_actor_event (grab_actor, event, FALSE);
+    }
+  else
+    {
+      /* no grab, time to capture and bubble */
+      emit_event (event, FALSE);
+    }
+}
+
 static inline void
 emit_keyboard_event (ClutterEvent       *event,
                      ClutterInputDevice *device)
@@ -2644,7 +2664,7 @@ _clutter_process_event_details (ClutterActor        *stage,
                         x, y,
                         actor);
 
-          emit_pointer_event (event, device);
+          emit_touch_event (event, device);
           break;
         }
 

clutter/clutter-types.h

@@ -90,8 +90,20 @@ typedef struct _ClutterAnimation                ClutterAnimation;
 typedef struct _ClutterAnimator         	ClutterAnimator;
 typedef struct _ClutterState            	ClutterState;
 
+typedef struct _ClutterInputDevice              ClutterInputDevice;
+
 typedef union _ClutterEvent                     ClutterEvent;
 
+/**
+ * ClutterEventSequence:
+ *
+ * The <structname>ClutterEventSequence</structname> structure is an opaque
+ * type used to denote the event sequence of a touch event.
+ *
+ * Since: 1.12
+ */
+typedef struct _ClutterEventSequence            ClutterEventSequence;
+
 typedef struct _ClutterFog                      ClutterFog; /* deprecated */
 typedef struct _ClutterBehaviour                ClutterBehaviour; /* deprecated */
 typedef struct _ClutterShader                   ClutterShader; /* deprecated */

clutter/clutter.symbols

@@ -827,6 +827,9 @@ clutter_input_device_get_slave_devices
 clutter_input_device_get_type
 clutter_input_device_grab
 clutter_input_device_keycode_to_evdev
+clutter_input_device_sequence_get_grabbed_actor
+clutter_input_device_sequence_grab
+clutter_input_device_sequence_ungrab
 clutter_input_device_set_enabled
 clutter_input_device_set_key
 clutter_input_device_type_get_type

doc/reference/clutter/clutter-sections.txt

@@ -1184,6 +1184,9 @@ clutter_input_device_get_pointer_stage
 clutter_input_device_grab
 clutter_input_device_ungrab
 clutter_input_device_get_grabbed_actor
+clutter_input_device_sequence_grab
+clutter_input_device_sequence_ungrab
+clutter_input_device_sequence_get_grabbed_actor
 
 <SUBSECTION>
 clutter_input_device_update_from_event