clutter: Drop click count from button events

This does two things to frown upon:
- Modifies ClutterEvent structs, while the effort is to have those
  completely opaque, and readonly after creation from the input
  thread side.
- Stores state in the ClutterInputDevice struct, event though those
  are also considered static after creation, managed by the input
  thread, etc.

Stop doing that. This makes all events just forwarded as-is in
the ClutterStage/clutter-main.c code.

Handling of click count sounds like material for a ClutterGestureAction
(or perhaps ClutterClickAction), all of both callers now do it in place
at the moment, while gestures lack a better state tracking and management.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2024>

clutter/clutter/clutter-event.c

@@ -823,27 +823,6 @@ clutter_event_set_button (ClutterEvent *event,
   event->button.button = button;
 }
 
-/**
- * clutter_event_get_click_count:
- * @event: a #ClutterEvent of type %CLUTTER_BUTTON_PRESS or
- *   of type %CLUTTER_BUTTON_RELEASE
- *
- * Retrieves the number of clicks of @event
- *
- * Return value: the click count
- *
- * Since: 1.0
- */
-guint32
-clutter_event_get_click_count (const ClutterEvent *event)
-{
-  g_return_val_if_fail (event != NULL, 0);
-  g_return_val_if_fail (event->type == CLUTTER_BUTTON_PRESS ||
-                        event->type == CLUTTER_BUTTON_RELEASE, 0);
-
-  return event->button.click_count;
-}
-
 /* keys */
 
 /**

clutter/clutter/clutter-event.h

@@ -188,8 +188,6 @@ struct _ClutterKeyEvent
  * @y: event Y coordinate, relative to the stage
  * @modifier_state: button modifiers
  * @button: event button
- * @click_count: number of button presses within the default time
- *   and radius
  * @axes: reserved for future use
  * @device: the device that originated the event. If you want the physical
  * device the event originated from, use clutter_event_get_source_device()
@@ -214,7 +212,6 @@ struct _ClutterButtonEvent
   gfloat y;
   ClutterModifierType modifier_state;
   guint32 button;
-  guint click_count;
   gdouble *axes; /* Future use */
   ClutterInputDevice *device;
   uint32_t evdev_code;
@@ -740,8 +737,6 @@ void                    clutter_event_set_button                (ClutterEvent
 CLUTTER_EXPORT
 guint32                 clutter_event_get_button                (const ClutterEvent     *event);
 CLUTTER_EXPORT
-guint                   clutter_event_get_click_count           (const ClutterEvent     *event);
-CLUTTER_EXPORT
 void                    clutter_event_set_related               (ClutterEvent           *event,
                                                                  ClutterActor           *actor);
 CLUTTER_EXPORT

clutter/clutter/clutter-input-device-private.h

@@ -59,16 +59,6 @@ struct _ClutterInputDevice
   GHashTable   *sequence_grab_actors;
   GHashTable   *inv_sequence_grab_actors;
 
-  /* the current click count */
-  int click_count;
-  int current_button_number;
-
-  /* the previous state, used for click count generation */
-  int previous_x;
-  int previous_y;
-  uint32_t previous_time;
-  int previous_button_number;
-
   /* Accessiblity */
   ClutterVirtualInputDevice *accessibility_virtual_device;
   ClutterPtrA11yData *ptr_a11y_data;

clutter/clutter/clutter-input-device.c

@@ -427,13 +427,6 @@ clutter_input_device_init (ClutterInputDevice *self)
     clutter_input_device_get_instance_private (self);
 
   priv->device_type = CLUTTER_POINTER_DEVICE;
-
-  self->click_count = 0;
-
-  self->previous_time = CLUTTER_CURRENT_TIME;
-  self->previous_x = -1;
-  self->previous_y = -1;
-  self->current_button_number = self->previous_button_number = -1;
 }
 
 /**

clutter/clutter/clutter-main.c

@@ -674,107 +674,6 @@ _clutter_boolean_continue_accumulator (GSignalInvocationHint *ihint,
   return continue_emission;
 }
 
-static void
-event_click_count_generate (ClutterEvent *event)
-{
-  /* multiple button click detection */
-  static gint    click_count            = 0;
-  static gint    previous_x             = -1;
-  static gint    previous_y             = -1;
-  static guint32 previous_time          = 0;
-  static gint    previous_button_number = -1;
-
-  ClutterInputDevice *device = NULL;
-  ClutterSettings *settings;
-  guint double_click_time;
-  guint double_click_distance;
-
-  settings = clutter_settings_get_default ();
-
-  g_object_get (settings,
-                "double-click-distance", &double_click_distance,
-                "double-click-time", &double_click_time,
-                NULL);
-
-  device = clutter_event_get_device (event);
-  if (device != NULL)
-    {
-      click_count = device->click_count;
-      previous_x = device->previous_x;
-      previous_y = device->previous_y;
-      previous_time = device->previous_time;
-      previous_button_number = device->previous_button_number;
-
-      CLUTTER_NOTE (EVENT,
-                    "Restoring previous click count:%d (device:%s, time:%u)",
-                    click_count,
-                    clutter_input_device_get_device_name (device),
-                    previous_time);
-    }
-  else
-    {
-      CLUTTER_NOTE (EVENT,
-                    "Restoring previous click count:%d (time:%u)",
-                    click_count,
-                    previous_time);
-    }
-
-  switch (clutter_event_type (event))
-    {
-      case CLUTTER_BUTTON_PRESS:
-        /* check if we are in time and within distance to increment an
-         * existing click count
-         */
-        if (event->button.button == previous_button_number &&
-            event->button.time < (previous_time + double_click_time) &&
-            (ABS (event->button.x - previous_x) <= double_click_distance) &&
-            (ABS (event->button.y - previous_y) <= double_click_distance))
-          {
-            CLUTTER_NOTE (EVENT, "Increase click count (button: %d, time: %u)",
-                          event->button.button,
-                          event->button.time);
-
-            click_count += 1;
-          }
-        else /* start a new click count*/
-          {
-            CLUTTER_NOTE (EVENT, "Reset click count (button: %d, time: %u)",
-                          event->button.button,
-                          event->button.time);
-
-            click_count = 1;
-            previous_button_number = event->button.button;
-          }
-
-        previous_x = event->button.x;
-        previous_y = event->button.y;
-        previous_time = event->button.time;
-
-        G_GNUC_FALLTHROUGH;
-      case CLUTTER_BUTTON_RELEASE:
-        event->button.click_count = click_count;
-        break;
-
-      default:
-        g_assert_not_reached ();
-        break;
-    }
-
-  if (event->type == CLUTTER_BUTTON_PRESS && device != NULL)
-    {
-      CLUTTER_NOTE (EVENT, "Storing click count: %d (device:%s, time:%u)",
-                    click_count,
-                    clutter_input_device_get_device_name (device),
-                    previous_time);
-
-      device->click_count = click_count;
-      device->previous_x = previous_x;
-      device->previous_y = previous_y;
-      device->previous_time = previous_time;
-      device->previous_button_number = previous_button_number;
-    }
-}
-
 static inline void
 emit_event_chain (ClutterEvent *event)
 {
@@ -789,7 +688,7 @@ emit_event_chain (ClutterEvent *event)
 
 /*
  * Emits a pointer event after having prepared the event for delivery (setting
- * source, computing click_count, generating enter/leave etc.).
+ * source, generating enter/leave etc.).
  */
 
 static inline void
@@ -1266,7 +1165,6 @@ _clutter_process_event_details (ClutterActor        *stage,
                                     x, y);
 
                       event->button.source = stage;
-                      event->button.click_count = 1;
 
                       emit_pointer_event (event, device);
                     }
@@ -1311,14 +1209,6 @@ _clutter_process_event_details (ClutterActor        *stage,
                         x, y,
                         event->any.source);
 
-          /* button presses and releases need a click count */
-          if (event->type == CLUTTER_BUTTON_PRESS ||
-              event->type == CLUTTER_BUTTON_RELEASE)
-            {
-              /* Generate click count */
-              event_click_count_generate (event);
-            }
-
           emit_pointer_event (event, device);
           break;
         }