From ab0428a82f8233829c36e2a3ac0ed0848571c59d Mon Sep 17 00:00:00 2001

From: "Owen W. Taylor" <otaylor@fishsoup.net>

Date: Wed, 9 Jun 2010 19:38:35 -0400

Subject: [PATCH] Stop confusing GDK's grab tracking

With client side windows, mixing GDK event delivery with explicit calls

to XUngrabPointer() can result in GDK losing button release events

it expects to get. This means that GDK thinks there is an implicit

grab in effect when there is none and send events to the wrong window.

Avoid this by bypassing GDK's event handling for most mouse events.

We do a simplified conversion of the X event into a GdkEvent and send

it to directly to libgtk for delivery.

We make an exception when a GDK grab is already in effect - this is

needed for the correct operation of menus.

http://bugzilla.gnome.org/show_bug.cgi?id=599181

---

 src/core/display-private.h |    7 ++

 src/core/display.c         |  131 ++++++++++++++++++++++++++++++++++++++++++++

 2 files changed, 138 insertions(+), 0 deletions(-)

diff --git a/src/core/display-private.h b/src/core/display-private.h

index fee321c..7f779fd 100644

--- a/src/core/display-private.h

+++ b/src/core/display-private.h

@@ -232,6 +232,13 @@ struct _MetaDisplay

   /* Closing down the display */

   int closing;

+  /* To detect double clicks */

+  guint button_click_number;

+  Window button_click_window;

+  int button_click_x;

+  int button_click_y;

+  guint32 button_click_time;

+

   /* Managed by group.c */

   GHashTable *groups_by_leader;

diff --git a/src/core/display.c b/src/core/display.c

index 5bcf025..0c5f61d 100644

--- a/src/core/display.c

+++ b/src/core/display.c

@@ -77,6 +77,7 @@

 #include <X11/extensions/Xfixes.h>

 #endif

 #include <string.h>

+#include <gtk/gtk.h>

 #define GRAB_OP_IS_WINDOW_SWITCH(g)                     \

         (g == META_GRAB_OP_KEYBOARD_TABBING_NORMAL  ||  \

@@ -1362,6 +1363,133 @@ meta_display_queue_autoraise_callback (MetaDisplay *display,

   display->autoraise_window = window;

 }

+/* We do some of our event handling in core/frames.c, which expects

+ * GDK events delivered by GTK+.  However, since the transition to

+ * client side windows, we can't let GDK see button events, since the

+ * client-side tracking of implicit and explicit grabs it does will

+ * get confused by our direct use of X grabs.

+ *

+ * So we do a very minimal GDK => GTK event conversion here and send on the

+ * events we care about, and then filter them out so they don't go

+ * through the normal GDK event handling.

+ *

+ * To reduce the amount of code, the only events fields filled out

+ * below are the ones that frames.c uses. If frames.c is modified to

+ * use more fields, more fields need to be filled out below.

+ */

+

+static gboolean

+maybe_send_event_to_gtk (MetaDisplay *display,

+                         XEvent      *xevent)

+{

+  /* We're always using the default display */

+  GdkDisplay *gdk_display = gdk_display_get_default ();

+  GdkEvent gdk_event;

+  GdkWindow *gdk_window;

+  Window window;

+

+  switch (xevent->type)

+    {

+    case ButtonPress:

+    case ButtonRelease:

+      window = xevent->xbutton.window;

+      break;

+    case MotionNotify:

+      window = xevent->xmotion.window;

+      break;

+    case EnterNotify:

+    case LeaveNotify:

+      window = xevent->xcrossing.window;

+      break;

+    default:

+      return FALSE;

+    }

+

+  gdk_window = gdk_window_lookup_for_display (gdk_display, window);

+  if (gdk_window == NULL)

+    return FALSE;

+

+  /* If GDK already things it has a grab, we better let it see events; this

+   * is the menu-navigation case and events need to get sent to the appropriate

+   * (client-side) subwindow for individual menu items.

+   */

+  if (gdk_display_pointer_is_grabbed (gdk_display))

+    return FALSE;

+

+  memset (&gdk_event, 0, sizeof (gdk_event));

+

+  switch (xevent->type)

+    {

+    case ButtonPress:

+    case ButtonRelease:

+      if (xevent->type == ButtonPress)

+        {

+          GtkSettings *settings = gtk_settings_get_default ();

+          int double_click_time;

+          int double_click_distance;

+

+          g_object_get (settings,

+                        "gtk-double-click-time", &double_click_time,

+                        "gtk-double-click-distance", &double_click_distance,

+                        NULL);

+

+          if (xevent->xbutton.button == display->button_click_number &&

+              xevent->xbutton.window == display->button_click_window &&

+              xevent->xbutton.time < display->button_click_time + double_click_time &&

+              ABS (xevent->xbutton.x - display->button_click_x) <= double_click_distance &&

+              ABS (xevent->xbutton.y - display->button_click_y) <= double_click_distance)

+            {

+              gdk_event.button.type = GDK_2BUTTON_PRESS;

+

+              display->button_click_number = 0;

+            }

+          else

+            {

+              gdk_event.button.type = GDK_BUTTON_PRESS;

+              display->button_click_number = xevent->xbutton.button;

+              display->button_click_window = xevent->xbutton.window;

+              display->button_click_time = xevent->xbutton.time;

+              display->button_click_x = xevent->xbutton.x;

+              display->button_click_y = xevent->xbutton.y;

+            }

+        }

+      else

+        {

+          gdk_event.button.type = GDK_BUTTON_RELEASE;

+        }

+

+      gdk_event.button.window = gdk_window;

+      gdk_event.button.button = xevent->xbutton.button;

+      gdk_event.button.time = xevent->xbutton.time;

+      gdk_event.button.x = xevent->xbutton.x;

+      gdk_event.button.y = xevent->xbutton.y;

+      gdk_event.button.x_root = xevent->xbutton.x_root;

+      gdk_event.button.y_root = xevent->xbutton.y_root;

+

+      break;

+    case MotionNotify:

+      gdk_event.motion.type = GDK_MOTION_NOTIFY;

+      gdk_event.motion.window = gdk_window;

+      break;

+    case EnterNotify:

+    case LeaveNotify:

+      gdk_event.crossing.type = xevent->type == EnterNotify ? GDK_ENTER_NOTIFY : GDK_LEAVE_NOTIFY;

+      gdk_event.crossing.window = gdk_window;

+      gdk_event.crossing.x = xevent->xcrossing.x;

+      gdk_event.crossing.y = xevent->xcrossing.y;

+      break;

+    default:

+      g_assert_not_reached ();

+      break;

+    }

+

+  /* If we've gotten here, we've filled in the gdk_event and should send it on */

+

+  gtk_main_do_event (&gdk_event);

+

+  return TRUE;

+}

+

 /**

  * This is the most important function in the whole program. It is the heart,

  * it is the nexus, it is the Grand Central Station of Metacity's world.

@@ -2387,6 +2515,9 @@ event_callback (XEvent   *event,

 				     event,

 				     window);

     }

+

+  if (maybe_send_event_to_gtk (display, event))

+    filter_out_event = TRUE;

   display->current_time = CurrentTime;

   return filter_out_event;

-- 

1.7.9