[mutter] backends/native: Release virtual buttons on dispose instead of finalize

[verdre <jonasd src gnome org>]

commit 9f31e7252c1bed04f0fd323f8484e6aabf3451e4
Author: Jonas Dreßler <verdre v0yd nl>
Date:   Sat Mar 28 11:34:49 2020 +0100

    backends/native: Release virtual buttons on dispose instead of finalize
    
    GObject recommends to break references to other objects on dispose
    instead of finalize, also we want to release the pressed virtual buttons
    as early as possible if we know the object is getting destroyed.
    
    So release the pressed buttons and unref our virtual
    MetaInputDeviceNative when the dispose vfunc is called, which also
    allows us to release the buttons immediately from javascript instead of
    waiting for the garbage collector by calling run_dispose() on the
    object.
    
    https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1157

 .../native/meta-virtual-input-device-native.c      | 44 ++++++++++++++++------
 1 file changed, 33 insertions(+), 11 deletions(-)
---
diff --git a/src/backends/native/meta-virtual-input-device-native.c 
b/src/backends/native/meta-virtual-input-device-native.c
index 194657f0d..9e99c3a5f 100644
--- a/src/backends/native/meta-virtual-input-device-native.c
+++ b/src/backends/native/meta-virtual-input-device-native.c
@@ -155,6 +155,8 @@ meta_virtual_input_device_native_notify_relative_motion (ClutterVirtualInputDevi
   MetaVirtualInputDeviceNative *virtual_evdev =
     META_VIRTUAL_INPUT_DEVICE_NATIVE (virtual_device);
 
+  g_return_if_fail (virtual_evdev->device != NULL);
+
   if (time_us == CLUTTER_CURRENT_TIME)
     time_us = g_get_monotonic_time ();
 
@@ -174,6 +176,8 @@ meta_virtual_input_device_native_notify_absolute_motion (ClutterVirtualInputDevi
   MetaVirtualInputDeviceNative *virtual_evdev =
     META_VIRTUAL_INPUT_DEVICE_NATIVE (virtual_device);
 
+  g_return_if_fail (virtual_evdev->device != NULL);
+
   if (time_us == CLUTTER_CURRENT_TIME)
     time_us = g_get_monotonic_time ();
 
@@ -215,6 +219,8 @@ meta_virtual_input_device_native_notify_button (ClutterVirtualInputDevice *virtu
   int button_count;
   int evdev_button;
 
+  g_return_if_fail (virtual_evdev->device != NULL);
+
   if (time_us == CLUTTER_CURRENT_TIME)
     time_us = g_get_monotonic_time ();
 
@@ -258,6 +264,8 @@ meta_virtual_input_device_native_notify_key (ClutterVirtualInputDevice *virtual_
     META_VIRTUAL_INPUT_DEVICE_NATIVE (virtual_device);
   int key_count;
 
+  g_return_if_fail (virtual_evdev->device != NULL);
+
   if (time_us == CLUTTER_CURRENT_TIME)
     time_us = g_get_monotonic_time ();
 
@@ -395,6 +403,8 @@ meta_virtual_input_device_native_notify_keyval (ClutterVirtualInputDevice *virtu
   int key_count;
   guint keycode = 0, level = 0, evcode = 0;
 
+  g_return_if_fail (virtual_evdev->device != NULL);
+
   if (time_us == CLUTTER_CURRENT_TIME)
     time_us = g_get_monotonic_time ();
 
@@ -482,6 +492,8 @@ meta_virtual_input_device_native_notify_discrete_scroll (ClutterVirtualInputDevi
     META_VIRTUAL_INPUT_DEVICE_NATIVE (virtual_device);
   double discrete_dx = 0.0, discrete_dy = 0.0;
 
+  g_return_if_fail (virtual_evdev->device != NULL);
+
   if (time_us == CLUTTER_CURRENT_TIME)
     time_us = g_get_monotonic_time ();
 
@@ -505,6 +517,8 @@ meta_virtual_input_device_native_notify_scroll_continuous (ClutterVirtualInputDe
   MetaVirtualInputDeviceNative *virtual_evdev =
     META_VIRTUAL_INPUT_DEVICE_NATIVE (virtual_device);
 
+  g_return_if_fail (virtual_evdev->device != NULL);
+
   if (time_us == CLUTTER_CURRENT_TIME)
     time_us = g_get_monotonic_time ();
 
@@ -529,6 +543,8 @@ meta_virtual_input_device_native_notify_touch_down (ClutterVirtualInputDevice *v
     META_INPUT_DEVICE_NATIVE (virtual_evdev->device);
   MetaTouchState *touch_state;
 
+  g_return_if_fail (virtual_evdev->device != NULL);
+
   if (time_us == CLUTTER_CURRENT_TIME)
     time_us = g_get_monotonic_time ();
 
@@ -562,6 +578,8 @@ meta_virtual_input_device_native_notify_touch_motion (ClutterVirtualInputDevice
     META_INPUT_DEVICE_NATIVE (virtual_evdev->device);
   MetaTouchState *touch_state;
 
+  g_return_if_fail (virtual_evdev->device != NULL);
+
   if (time_us == CLUTTER_CURRENT_TIME)
     time_us = g_get_monotonic_time ();
 
@@ -593,6 +611,8 @@ meta_virtual_input_device_native_notify_touch_up (ClutterVirtualInputDevice *vir
     META_INPUT_DEVICE_NATIVE (virtual_evdev->device);
   MetaTouchState *touch_state;
 
+  g_return_if_fail (virtual_evdev->device != NULL);
+
   if (time_us == CLUTTER_CURRENT_TIME)
     time_us = g_get_monotonic_time ();
 
@@ -682,24 +702,26 @@ meta_virtual_input_device_native_constructed (GObject *object)
 }
 
 static void
-meta_virtual_input_device_native_finalize (GObject *object)
+meta_virtual_input_device_native_dispose (GObject *object)
 {
   ClutterVirtualInputDevice *virtual_device =
     CLUTTER_VIRTUAL_INPUT_DEVICE (object);
   MetaVirtualInputDeviceNative *virtual_evdev =
     META_VIRTUAL_INPUT_DEVICE_NATIVE (object);
-  GObjectClass *object_class;
+  GObjectClass *object_class =
+    G_OBJECT_CLASS (meta_virtual_input_device_native_parent_class);
 
-  release_pressed_buttons (virtual_device);
-  g_signal_emit_by_name (virtual_evdev->seat,
-                         "device-removed",
-                         virtual_evdev->device);
+  if (virtual_evdev->device)
+    {
+      release_pressed_buttons (virtual_device);
+      g_signal_emit_by_name (virtual_evdev->seat,
+                             "device-removed",
+                             virtual_evdev->device);
 
-  g_clear_object (&virtual_evdev->device);
+      g_clear_object (&virtual_evdev->device);
+    }
 
-  object_class =
-    G_OBJECT_CLASS (meta_virtual_input_device_native_parent_class);
-  object_class->finalize (object);
+  object_class->dispose (object);
 }
 
 static void
@@ -717,7 +739,7 @@ meta_virtual_input_device_native_class_init (MetaVirtualInputDeviceNativeClass *
   object_class->get_property = meta_virtual_input_device_native_get_property;
   object_class->set_property = meta_virtual_input_device_native_set_property;
   object_class->constructed = meta_virtual_input_device_native_constructed;
-  object_class->finalize = meta_virtual_input_device_native_finalize;
+  object_class->dispose = meta_virtual_input_device_native_dispose;
 
   virtual_input_device_class->notify_relative_motion = 
meta_virtual_input_device_native_notify_relative_motion;
   virtual_input_device_class->notify_absolute_motion = 
meta_virtual_input_device_native_notify_absolute_motion;