wayland: sync the keymap from X to wayland

When X clients change the keyboard map, the also update a property
on the root window. We can notice that and rebuild our data structures
with the new values, as well as inform the wayland clients.

This is a terrible hack, and it's not how we want to implement things
in 3.12, but it's enough to have the same keyboard layout in the
shell, in X clients and in wayland clients in 3.10, until we decide
on the fate of the keyboard g-s-d plugin.

https://bugzilla.gnome.org/show_bug.cgi?id=707446

src/core/display.c

@@ -2191,6 +2191,40 @@ handle_window_focus_event (MetaDisplay  *display,
     }
 }
 
+static void
+reload_xkb_rules (MetaScreen  *screen)
+{
+  MetaWaylandCompositor *compositor;
+  char **names;
+  int n_names;
+  gboolean ok;
+  const char *rules, *model, *layout, *variant, *options;
+
+  compositor = meta_wayland_compositor_get_default ();
+
+  ok = meta_prop_get_latin1_list (screen->display, screen->xroot,
+                                  screen->display->atom__XKB_RULES_NAMES,
+                                  &names, &n_names);
+  if (!ok)
+    return;
+
+  if (n_names != 5)
+    goto out;
+
+  rules = names[0];
+  model = names[1];
+  layout = names[2];
+  variant = names[3];
+  options = names[4];
+
+  meta_wayland_keyboard_set_keymap_names (&compositor->seat->keyboard,
+                                          rules, model, layout, variant, options,
+                                          META_WAYLAND_KEYBOARD_SKIP_XCLIENTS);
+
+ out:
+  g_strfreev (names);
+}
+
 /**
  * meta_display_handle_event:
  * @display: The MetaDisplay that events are coming from
@@ -2964,6 +2998,10 @@ meta_display_handle_event (MetaDisplay *display,
                 else if (event->xproperty.atom ==
                          display->atom__NET_DESKTOP_NAMES)
                   meta_screen_update_workspace_names (screen);
+                else if (meta_is_wayland_compositor () &&
+                         event->xproperty.atom ==
+                         display->atom__XKB_RULES_NAMES)
+                  reload_xkb_rules (screen);
 #if 0
                 else if (event->xproperty.atom ==
                          display->atom__NET_RESTACK_WINDOW)

src/core/xprops.c

@@ -536,6 +536,81 @@ meta_prop_get_utf8_list (MetaDisplay   *display,
   return utf8_list_from_results (&results, str_p, n_str_p);
 }
 
+/* this one freakishly returns g_malloc memory */
+static gboolean
+latin1_list_from_results (GetPropertyResults *results,
+                        char             ***str_p,
+                        int                *n_str_p)
+{
+  int i;
+  int n_strings;
+  char **retval;
+  const char *p;
+  
+  *str_p = NULL;
+  *n_str_p = 0;
+
+  if (!validate_or_free_results (results, 8, XA_STRING, FALSE))
+    return FALSE;
+  
+  /* I'm not sure this is right, but I'm guessing the
+   * property is nul-separated
+   */
+  i = 0;
+  n_strings = 0;
+  while (i < (int) results->n_items)
+    {
+      if (results->prop[i] == '\0')
+        ++n_strings;
+      ++i;
+    }
+
+  if (results->prop[results->n_items - 1] != '\0')
+    ++n_strings;
+ 
+  /* we're guaranteed that results->prop has a nul on the end
+   * by XGetWindowProperty
+   */
+  
+  retval = g_new0 (char*, n_strings + 1);
+
+  p = (char *)results->prop;
+  i = 0;
+  while (i < n_strings)
+    {
+      retval[i] = g_strdup (p);
+      
+      p = p + strlen (p) + 1;
+      ++i;
+    }
+  
+  *str_p = retval;
+  *n_str_p = i;
+
+  meta_XFree (results->prop);
+  results->prop = NULL;
+
+  return TRUE;
+}
+
+gboolean
+meta_prop_get_latin1_list (MetaDisplay   *display,
+                           Window         xwindow,
+                           Atom           xatom,
+                           char        ***str_p,
+                           int           *n_str_p)
+{
+  GetPropertyResults results;
+
+  *str_p = NULL;
+
+  if (!get_property (display, xwindow, xatom,
+                     XA_STRING, &results))
+    return FALSE;
+
+  return latin1_list_from_results (&results, str_p, n_str_p);
+}
+
 void
 meta_prop_set_utf8_string_hint (MetaDisplay *display,
                                 Window xwindow,

src/core/xprops.h

@@ -102,6 +102,11 @@ gboolean meta_prop_get_utf8_list     (MetaDisplay   *display,
                                       Atom           xatom,
                                       char        ***str_p,
                                       int           *n_str_p);
+gboolean meta_prop_get_latin1_list   (MetaDisplay   *display,
+                                      Window         xwindow,
+                                      Atom           xatom,
+                                      char        ***str_p,
+                                      int           *n_str_p);
 void     meta_prop_set_utf8_string_hint
                                      (MetaDisplay *display,
                                       Window xwindow,