util: Add INPUT debug topic

Allow debugging input issues more easily by adding an INPUT debug topic.
Currently there are only debug messages for the native backend.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/1065

src/backends/native/meta-seat-native.c

@@ -275,7 +275,12 @@ update_button_count (MetaSeatNative *seat,
     {
       /* Handle cases where we newer saw the initial pressed event. */
       if (seat->button_count[button] == 0)
+        {
+          meta_topic (META_DEBUG_INPUT,
+                      "Counting release of key 0x%x and count is already 0\n",
+                      button);
           return 0;
+        }
 
       return --seat->button_count[button];
     }
@@ -297,11 +302,15 @@ meta_seat_native_notify_key (MetaSeatNative     *seat,
     {
       /* Drop any repeated button press (for example from virtual devices. */
       int count = update_button_count (seat, key, state);
-      if (state && count > 1)
+      if ((state && count > 1) ||
-        return;
+          (!state && count != 0))
-      if (!state && count != 0)
+        {
+          meta_topic (META_DEBUG_INPUT,
+                      "Dropping repeated %s of key 0x%x, count %d, state %d\n",
+                      state ? "press" : "release", key, count, state);
           return;
         }
+    }
 
   /* We can drop the event on the floor if no stage has been
    * associated with the device yet. */
@@ -514,10 +523,14 @@ meta_seat_native_notify_button (MetaSeatNative     *seat,
 
   /* Drop any repeated button press (for example from virtual devices. */
   button_count = update_button_count (seat, button, state);
-  if (state && button_count > 1)
+  if ((state && button_count > 1) ||
-    return;
+      (!state && button_count != 0))
-  if (!state && button_count != 0)
+    {
+      meta_topic (META_DEBUG_INPUT,
+                  "Dropping repeated %s of button 0x%x, count %d\n",
+                  state ? "press" : "release", button, button_count);
       return;
+    }
 
   /* We can drop the event on the floor if no stage has been
    * associated with the device yet. */
@@ -1840,7 +1853,14 @@ process_device_event (MetaSeatNative        *seat,
 	     seat_key_count != 1) ||
 	    (key_state == LIBINPUT_KEY_STATE_RELEASED &&
 	     seat_key_count != 0))
+          {
+            meta_topic (META_DEBUG_INPUT,
+                        "Dropping key-%s of key 0x%x because seat-wide "
+                        "key count is %d\n",
+                        key_state == LIBINPUT_KEY_STATE_PRESSED ? "press" : "release",
+                        key, seat_key_count);
             break;
+          }
 
         meta_seat_native_notify_key (seat_from_device (device),
                                      device,
@@ -1927,7 +1947,14 @@ process_device_event (MetaSeatNative        *seat,
              seat_button_count != 1) ||
             (button_state == LIBINPUT_BUTTON_STATE_RELEASED &&
              seat_button_count != 0))
+          {
+            meta_topic (META_DEBUG_INPUT,
+                        "Dropping button-%s of button 0x%x because seat-wide "
+                        "button count is %d\n",
+                        button_state == LIBINPUT_BUTTON_STATE_PRESSED ? "press" : "release",
+                        button, seat_button_count);
             break;
+          }
 
         meta_seat_native_notify_button (seat_from_device (device), device,
                                         time_us, button, button_state);

src/backends/native/meta-virtual-input-device-native.c

@@ -27,6 +27,7 @@
 #include "backends/native/meta-seat-native.h"
 #include "backends/native/meta-virtual-input-device-native.h"
 #include "clutter/clutter-mutter.h"
+#include "meta/util.h"
 
 enum
 {
@@ -116,6 +117,10 @@ release_pressed_buttons (ClutterVirtualInputDevice *virtual_device)
 
   time_us = g_get_monotonic_time ();
 
+  meta_topic (META_DEBUG_INPUT,
+              "Releasing pressed buttons while destroying virtual input device "
+              "(device %p)\n", virtual_device);
+
   for (code = 0; code < G_N_ELEMENTS (virtual_evdev->button_count); code++)
     {
       if (virtual_evdev->button_count[code] == 0)
@@ -231,6 +236,11 @@ meta_virtual_input_device_native_notify_button (ClutterVirtualInputDevice *virtu
       return;
     }
 
+  meta_topic (META_DEBUG_INPUT,
+              "Emitting virtual button-%s of button 0x%x (device %p)\n",
+              button_state == CLUTTER_BUTTON_STATE_PRESSED ? "press" : "release",
+              evdev_button, virtual_device);
+
   meta_seat_native_notify_button (virtual_evdev->seat,
                                   virtual_evdev->device,
                                   time_us,
@@ -266,6 +276,11 @@ meta_virtual_input_device_native_notify_key (ClutterVirtualInputDevice *virtual_
       return;
     }
 
+  meta_topic (META_DEBUG_INPUT,
+              "Emitting virtual key-%s of key 0x%x (device %p)\n",
+              key_state == CLUTTER_KEY_STATE_PRESSED ? "press" : "release",
+              key, virtual_device);
+
   meta_seat_native_notify_key (virtual_evdev->seat,
                                virtual_evdev->device,
                                time_us,
@@ -355,6 +370,12 @@ apply_level_modifiers (ClutterVirtualInputDevice *virtual_device,
 
   clutter_input_device_keycode_to_evdev (virtual_evdev->device,
                                          keycode, &evcode);
+
+  meta_topic (META_DEBUG_INPUT,
+              "Emitting virtual key-%s of modifier key 0x%x (device %p)\n",
+              key_state == CLUTTER_KEY_STATE_PRESSED ? "press" : "release",
+              evcode, virtual_device);
+
   meta_seat_native_notify_key (virtual_evdev->seat,
                                virtual_evdev->device,
                                time_us,
@@ -402,6 +423,12 @@ meta_virtual_input_device_native_notify_keyval (ClutterVirtualInputDevice *virtu
       return;
     }
 
+  meta_topic (META_DEBUG_INPUT,
+              "Emitting virtual key-%s of key 0x%x with modifier level %d, "
+              "press count %d (device %p)\n",
+              key_state == CLUTTER_KEY_STATE_PRESSED ? "press" : "release",
+              evcode, level, key_count, virtual_device);
+
   if (key_state)
     apply_level_modifiers (virtual_device, time_us, level, key_state);
 
@@ -637,6 +664,10 @@ meta_virtual_input_device_native_constructed (GObject *object)
 
   device_type = clutter_virtual_input_device_get_device_type (virtual_device);
 
+  meta_topic (META_DEBUG_INPUT,
+              "Creating new virtual input device of type %d (%p)\n",
+              device_type, virtual_device);
+
   virtual_evdev->device =
     meta_input_device_native_new_virtual (virtual_evdev->seat,
                                           device_type,

src/core/util.c

@@ -335,6 +335,8 @@ topic_name (MetaDebugTopic topic)
       return "EDGE_RESISTANCE";
     case META_DEBUG_DBUS:
       return "DBUS";
+    case META_DEBUG_INPUT:
+      return "INPUT";
     case META_DEBUG_VERBOSE:
       return "VERBOSE";
     }

src/meta/util.h

@@ -111,7 +111,8 @@ typedef enum
   META_DEBUG_SHAPES          = 1 << 19,
   META_DEBUG_COMPOSITOR      = 1 << 20,
   META_DEBUG_EDGE_RESISTANCE = 1 << 21,
-  META_DEBUG_DBUS            = 1 << 22
+  META_DEBUG_DBUS            = 1 << 22,
+  META_DEBUG_INPUT           = 1 << 23
 } MetaDebugTopic;
 
 META_EXPORT