From 2dd851d9f4aa60dfb36c59dab9dc86dfe9f8d0ff Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jonas=20Dre=C3=9Fler?= <verdre@v0yd.nl>
Date: Wed, 6 Apr 2022 12:19:27 +0200
Subject: [PATCH] clutter: Add a GRABS debug flag

Now that we have two kinds of grabs, the intricacies of event delivery
got slightly more complicated. So this seems like a good point to
introduce a new GRABS debug flag that gives an overview of which grabs
are currently in effect.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2342>
---
 clutter/clutter/clutter-main.c  |  1 +
 clutter/clutter/clutter-main.h  |  1 +
 clutter/clutter/clutter-stage.c | 45 +++++++++++++++++++++++++++++++++
 3 files changed, 47 insertions(+)

diff --git a/clutter/clutter/clutter-main.c b/clutter/clutter/clutter-main.c
index d589174d7..9be960f5e 100644
--- a/clutter/clutter/clutter-main.c
+++ b/clutter/clutter/clutter-main.c
@@ -116,6 +116,7 @@ static const GDebugKey clutter_debug_keys[] = {
   { "oob-transforms", CLUTTER_DEBUG_OOB_TRANSFORMS },
   { "frame-timings", CLUTTER_DEBUG_FRAME_TIMINGS },
   { "detailed-trace", CLUTTER_DEBUG_DETAILED_TRACE },
+  { "grabs", CLUTTER_DEBUG_GRABS },
 };
 #endif /* CLUTTER_ENABLE_DEBUG */
 
diff --git a/clutter/clutter/clutter-main.h b/clutter/clutter/clutter-main.h
index b9854956b..3315b7896 100644
--- a/clutter/clutter/clutter-main.h
+++ b/clutter/clutter/clutter-main.h
@@ -55,6 +55,7 @@ typedef enum
   CLUTTER_DEBUG_OOB_TRANSFORMS      = 1 << 16,
   CLUTTER_DEBUG_FRAME_TIMINGS       = 1 << 17,
   CLUTTER_DEBUG_DETAILED_TRACE      = 1 << 18,
+  CLUTTER_DEBUG_GRABS               = 1 << 19,
 } ClutterDebugFlag;
 
 typedef enum
diff --git a/clutter/clutter/clutter-stage.c b/clutter/clutter/clutter-stage.c
index 997f90c48..0d45b65af 100644
--- a/clutter/clutter/clutter-stage.c
+++ b/clutter/clutter/clutter-stage.c
@@ -4085,6 +4085,20 @@ clutter_stage_grab (ClutterStage *stage,
     priv->topmost_grab->prev = grab;
 
   priv->topmost_grab = grab;
+
+  if (G_UNLIKELY (clutter_debug_flags & CLUTTER_DEBUG_GRABS))
+    {
+      unsigned int n_grabs = 0;
+      ClutterGrab *g;
+
+      for (g = priv->topmost_grab; g != NULL; g = g->next)
+        n_grabs++;
+
+      CLUTTER_NOTE (GRABS,
+                    "[grab=%p] Attached seat grab (n_grabs: %u) on actor: %s",
+                    grab, n_grabs, _clutter_actor_get_debug_name (actor));
+    }
+
   clutter_actor_attach_grab (actor, grab);
   clutter_stage_notify_grab (stage, grab, grab->next);
 
@@ -4132,6 +4146,19 @@ clutter_stage_unlink_grab (ClutterStage *stage,
       priv->grab_state = CLUTTER_GRAB_STATE_NONE;
     }
 
+  if (G_UNLIKELY (clutter_debug_flags & CLUTTER_DEBUG_GRABS))
+    {
+      unsigned int n_grabs = 0;
+      ClutterGrab *g;
+
+      for (g = priv->topmost_grab; g != NULL; g = g->next)
+        n_grabs++;
+
+      CLUTTER_NOTE (GRABS,
+                    "[grab=%p] Detached seat grab (n_grabs: %u)",
+                    grab, n_grabs);
+    }
+
   grab->next = NULL;
   grab->prev = NULL;
 }
@@ -4311,6 +4338,10 @@ setup_implicit_grab (PointerDeviceEntry *entry)
       return FALSE;
     }
 
+  CLUTTER_NOTE (GRABS,
+                "[device=%p sequence=%p] Aquiring implicit grab",
+                entry->device, entry->sequence);
+
   g_assert (entry->press_count == 0);
   g_assert (entry->event_emission_chain->len == 0);
 
@@ -4331,6 +4362,10 @@ release_implicit_grab (PointerDeviceEntry *entry)
       return FALSE;
     }
 
+  CLUTTER_NOTE (GRABS,
+                "[device=%p sequence=%p] Releasing implicit grab",
+                entry->device, entry->sequence);
+
   g_assert (entry->press_count == 1);
 
   entry->press_count = 0;
@@ -4356,6 +4391,10 @@ clutter_stage_maybe_lost_implicit_grab (ClutterStage         *self,
   if (!entry->press_count)
     return;
 
+  CLUTTER_NOTE (GRABS,
+                "[device=%p sequence=%p] Lost implicit grab",
+                device, sequence);
+
   for (i = 0; i < entry->event_emission_chain->len; i++)
     {
       EventReceiver *receiver =
@@ -4504,6 +4543,12 @@ cancel_implicit_grab_on_actor (PointerDeviceEntry *entry,
   unsigned int i;
   ClutterActor *parent = clutter_actor_get_parent (actor);
 
+  CLUTTER_NOTE (GRABS,
+                "[device=%p sequence=%p] Cancelling implicit grab on actor (%s) "
+                "due to unmap",
+                entry->device, entry->sequence,
+                _clutter_actor_get_debug_name (actor));
+
   for (i = 0; i < entry->event_emission_chain->len; i++)
     {
       EventReceiver *receiver =