Cache the display name. There is only one GdkDisplay on Win32, and

2005-09-09  Tor Lillqvist  <tml@novell.com>

	* gdk/win32/gdkdisplay-win32.c (gdk_display_get_name): Cache the
	display name. There is only one GdkDisplay on Win32, and
	constructing the display name isn't entirely trivial, so cacheing
	is probably worth it. For instance GIMP calls this function a lot.
	(gdk_display_open): Call gdk_display_get_name() to prime the
	cached name.
	(gdk_display_get_n_screens, gdk_display_get_screen,
	gdk_display_get_default_screen): Verify parameter correctness like
	the X11 backend does.

	* gdk/win32/gdkscreen-win32.c (gdk_screen_make_display_name):
	Return a freshly allocated string, as the API specifies. Fixes a
	heap corruption problem that caused random errors and crashes in
	GIMP, for instance.

2 files changed, 21 insertions, 9 deletions

diff --git a/gdk/win32/gdkdisplay-win32.c b/gdk/win32/gdkdisplay-win32.c
index fe08e4584..499894857 100644
--- a/gdk/win32/gdkdisplay-win32.c
+++ b/gdk/win32/gdkdisplay-win32.c
@@ -236,6 +236,9 @@ gdk_display_open (const gchar *display_name)
   _gdk_input_init (_gdk_display);
   _gdk_dnd_init ();
 
+  /* Precalculate display name */
+  (void) gdk_display_get_name (_gdk_display);
+
   g_signal_emit_by_name (gdk_display_manager_get (),
 			 "display_opened", _gdk_display);
 
@@ -253,9 +256,13 @@ gdk_display_get_name (GdkDisplay *display)
   HWINSTA hwinsta = GetProcessWindowStation ();
   char *window_station_name;
   DWORD n;
-  DWORD session_id;
   char *display_name;
-  const char *retval;
+  static const char *display_name_cache = NULL;
+
+  g_return_val_if_fail (GDK_IS_DISPLAY (display), NULL);
+  
+  if (display_name_cache != NULL)
+    return display_name_cache;
 
   n = 0;
   GetUserObjectInformation (hdesk, UOI_NAME, &dummy, 0, &n);
@@ -285,22 +292,22 @@ gdk_display_get_name (GdkDisplay *display)
 	window_station_name = "WinSta0";
     }
 
-  display_name = g_strdup_printf ("%ld\\%s\\%s",
+  display_name = g_strdup_printf ("%d\\%s\\%s",
 				  get_session_id (), window_station_name,
 				  desktop_name);
 
-  retval = g_quark_to_string (g_quark_from_string (display_name));
-
-  g_free (display_name);
+  GDK_NOTE (MISC, g_print ("gdk_display_get_name: %s\n", display_name));
 
-  GDK_NOTE (MISC, g_print ("gdk_display_get_name: %s\n", retval));
+  display_name_cache = display_name;
 
-  return retval;
+  return display_name_cache;
 }
 
 gint
 gdk_display_get_n_screens (GdkDisplay *display)
 {
+  g_return_val_if_fail (GDK_IS_DISPLAY (display), 0);
+  
   return 1;
 }
 
@@ -308,12 +315,17 @@ GdkScreen *
 gdk_display_get_screen (GdkDisplay *display,
 			gint        screen_num)
 {
+  g_return_val_if_fail (GDK_IS_DISPLAY (display), NULL);
+  g_return_val_if_fail (screen_num != 0, NULL);
+
   return _gdk_screen;
 }
 
 GdkScreen *
 gdk_display_get_default_screen (GdkDisplay *display)
 {
+  g_return_val_if_fail (GDK_IS_DISPLAY (display), NULL);
+
   return _gdk_screen;
 }
 
diff --git a/gdk/win32/gdkscreen-win32.c b/gdk/win32/gdkscreen-win32.c
index 91e3ff6a2..59b5430cd 100644
--- a/gdk/win32/gdkscreen-win32.c
+++ b/gdk/win32/gdkscreen-win32.c
@@ -115,5 +115,5 @@ _gdk_windowing_substitute_screen_number (const gchar *display_name,
 gchar *
 gdk_screen_make_display_name (GdkScreen *screen)
 {
-  return gdk_display_get_name (_gdk_display);
+  return g_strdup (gdk_display_get_name (_gdk_display));
 }