[mutter] events: Simplify gesture event management

[Carlos Garnacho <carlosg src gnome org>]

commit 63c75916984a7f57ec714fcc0af139553be13084
Author: Carlos Garnacho <carlosg gnome org>
Date:   Tue Jul 22 01:55:02 2014 +0200

    events: Simplify gesture event management
    
    MetaGestureTracker has been separating the "did I handle an event?" and the
    "should the event be filtered out?" questions, merge this and make
    handle_event() reply to "should the event be only handled by me?".
    
    If a sequence wasn't accepted yet by the gesture tracker, the event will
    go through (eg. not handled exclusively by the gesture tracker) and it'll
    still be processed by Clutter, triggering gesture actions, and maybe
    changing the sequence into other state.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=733631

 src/core/events.c                       |    3 +-
 src/core/meta-gesture-tracker-private.h |    2 -
 src/core/meta-gesture-tracker.c         |   46 +++++++++++++++++--------------
 3 files changed, 26 insertions(+), 25 deletions(-)
---
diff --git a/src/core/events.c b/src/core/events.c
index f15e39d..9781754 100644
--- a/src/core/events.c
+++ b/src/core/events.c
@@ -204,8 +204,7 @@ meta_display_handle_event (MetaDisplay        *display,
 
   if (meta_gesture_tracker_handle_event (tracker, event))
     {
-      bypass_wayland = TRUE;
-      bypass_clutter = meta_gesture_tracker_consumes_event (tracker, event);
+      bypass_wayland = bypass_clutter = TRUE;
       goto out;
     }
 
diff --git a/src/core/meta-gesture-tracker-private.h b/src/core/meta-gesture-tracker-private.h
index 6f38274..0e39af2 100644
--- a/src/core/meta-gesture-tracker-private.h
+++ b/src/core/meta-gesture-tracker-private.h
@@ -70,8 +70,6 @@ gboolean             meta_gesture_tracker_set_sequence_state (MetaGestureTracker
                                                               MetaSequenceState     state);
 MetaSequenceState    meta_gesture_tracker_get_sequence_state (MetaGestureTracker   *tracker,
                                                               ClutterEventSequence *sequence);
-gboolean             meta_gesture_tracker_consumes_event     (MetaGestureTracker   *tracker,
-                                                              const ClutterEvent   *event);
 gint                 meta_gesture_tracker_get_n_current_touches (MetaGestureTracker *tracker);
 
 #endif /* META_GESTURE_TRACKER_PRIVATE_H */
diff --git a/src/core/meta-gesture-tracker.c b/src/core/meta-gesture-tracker.c
index 75a961c..ce56c62 100644
--- a/src/core/meta-gesture-tracker.c
+++ b/src/core/meta-gesture-tracker.c
@@ -413,6 +413,7 @@ meta_gesture_tracker_handle_event (MetaGestureTracker *tracker,
 {
   MetaGestureTrackerPrivate *priv;
   ClutterEventSequence *sequence;
+  MetaSequenceState state;
   MetaSequenceInfo *info;
   ClutterActor *stage;
   gfloat x, y;
@@ -446,6 +447,7 @@ meta_gesture_tracker_handle_event (MetaGestureTracker *tracker,
           meta_gesture_tracker_set_sequence_state (tracker, sequence,
                                                    priv->stage_state);
         }
+      state = info->state;
       break;
     case CLUTTER_TOUCH_END:
       info = g_hash_table_lookup (priv->sequences, sequence);
@@ -460,6 +462,7 @@ meta_gesture_tracker_handle_event (MetaGestureTracker *tracker,
         meta_gesture_tracker_set_sequence_state (tracker, sequence,
                                                  META_SEQUENCE_REJECTED);
 
+      state = info->state;
       g_hash_table_remove (priv->sequences, sequence);
 
       if (g_hash_table_size (priv->sequences) == 0)
@@ -478,13 +481,34 @@ meta_gesture_tracker_handle_event (MetaGestureTracker *tracker,
            ABS (info->start_y - y) > DISTANCE_THRESHOLD))
         meta_gesture_tracker_set_sequence_state (tracker, sequence,
                                                  META_SEQUENCE_REJECTED);
+      state = info->state;
       break;
     default:
       return FALSE;
       break;
     }
 
-  return TRUE;
+  /* As soon as a sequence is accepted, we replay it to
+   * the stage as a captured event, and make sure it's never
+   * propagated anywhere else. Since ClutterGestureAction does
+   * all its event handling from a captured-event handler on
+   * the stage, this effectively acts as a "sequence grab" on
+   * gesture actions.
+   *
+   * Sequences that aren't (yet or never) in an accepted state
+   * will go through, these events will get processed through
+   * the compositor, and eventually through clutter, still
+   * triggering the gestures capturing events on the stage, and
+   * possibly resulting in MetaSequenceState changes.
+   */
+  if (state == META_SEQUENCE_ACCEPTED)
+    {
+      clutter_actor_event (CLUTTER_ACTOR (clutter_event_get_stage (event)),
+                           event, TRUE);
+      return TRUE;
+    }
+
+  return FALSE;
 }
 
 gboolean
@@ -546,26 +570,6 @@ meta_gesture_tracker_get_sequence_state (MetaGestureTracker   *tracker,
   return info->state;
 }
 
-gboolean
-meta_gesture_tracker_consumes_event (MetaGestureTracker *tracker,
-                                     const ClutterEvent *event)
-{
-  ClutterEventSequence *sequence;
-  MetaSequenceState state;
-
-  g_return_val_if_fail (META_IS_GESTURE_TRACKER (tracker), FALSE);
-
-  sequence = clutter_event_get_event_sequence (event);
-
-  if (!sequence)
-    return FALSE;
-
-  state = meta_gesture_tracker_get_sequence_state (tracker, sequence);
-
-  return (event->type != CLUTTER_TOUCH_END &&
-          (state == META_SEQUENCE_REJECTED || state == META_SEQUENCE_PENDING_END));
-}
-
 gint
 meta_gesture_tracker_get_n_current_touches (MetaGestureTracker *tracker)
 {