[gtk/wip/carlosg/imwayland-3-22: 1/2] gdk/wayland: Add GdkDisplay call to query available globals

[Carlos Garnacho <carlosg src gnome org>]

commit 2aa1d6294edf6958b55a27dbe9f5b0ddf95cf367
Author: Carlos Garnacho <carlosg gnome org>
Date:   Tue Feb 13 14:28:44 2018 +0100

    gdk/wayland: Add GdkDisplay call to query available globals
    
    The internal known_globals hashtable is used to carry accounting for
    interfaces that depend on others (as ordering is not guaranteed), extend
    its usage so it also keeps track of unimplemented interfaces (here at
    least).
    
    The API call will then use this to allow querying the globals offered by
    the compositor, it will be useful to determine whether we can use
    text-input protocols or should fallback to other IMs.

 docs/reference/gdk/gdk3-sections.txt |  1 +
 gdk/wayland/gdkdisplay-wayland.c     | 42 ++++++++++++++++++++++++++++++------
 gdk/wayland/gdkwaylanddisplay.h      |  4 ++++
 3 files changed, 41 insertions(+), 6 deletions(-)
---
diff --git a/docs/reference/gdk/gdk3-sections.txt b/docs/reference/gdk/gdk3-sections.txt
index f26c22d3c6..4e5c403670 100644
--- a/docs/reference/gdk/gdk3-sections.txt
+++ b/docs/reference/gdk/gdk3-sections.txt
@@ -1270,6 +1270,7 @@ gdk_wayland_device_get_wl_seat
 gdk_wayland_display_get_wl_compositor
 gdk_wayland_display_get_wl_display
 gdk_wayland_display_get_xdg_shell
+gdk_wayland_display_query_registry
 gdk_wayland_window_get_wl_surface
 gdk_wayland_window_set_use_custom_surface
 GdkWaylandWindowExported
diff --git a/gdk/wayland/gdkdisplay-wayland.c b/gdk/wayland/gdkdisplay-wayland.c
index 8bcd6755a6..7839b6bcbb 100644
--- a/gdk/wayland/gdkdisplay-wayland.c
+++ b/gdk/wayland/gdkdisplay-wayland.c
@@ -372,7 +372,6 @@ gdk_registry_handle_global (void               *data,
 {
   GdkWaylandDisplay *display_wayland = data;
   struct wl_output *output;
-  gboolean handled = TRUE;
 
   GDK_NOTE (MISC,
             g_message ("add global %u, interface %s, version %u", id, interface, version));
@@ -495,12 +494,9 @@ gdk_registry_handle_global (void               *data,
                                                            &server_decoration_listener,
                                                            display_wayland);
     }
-  else
-    handled = FALSE;
 
-  if (handled)
-    g_hash_table_insert (display_wayland->known_globals,
-                         GUINT_TO_POINTER (id), g_strdup (interface));
+  g_hash_table_insert (display_wayland->known_globals,
+                       GUINT_TO_POINTER (id), g_strdup (interface));
 
   process_on_globals_closures (display_wayland);
 }
@@ -1386,3 +1382,37 @@ gdk_wayland_display_get_selection (GdkDisplay *display)
 
   return display_wayland->selection;
 }
+
+/**
+ * gdk_wayland_display_query_registry:
+ * @display: a wayland #GdkDisplay
+ * @interface: global interface to query in the registry
+ *
+ * Returns %TRUE if the the interface was found in the display
+ * wl_registry.global handler.
+ *
+ * Returns: %TRUE if the global is offered by the compositor
+ *
+ * Since: 3.22.27
+ **/
+gboolean
+gdk_wayland_display_query_registry (GdkDisplay  *display,
+                                   const gchar *global)
+{
+  GdkWaylandDisplay *display_wayland = GDK_WAYLAND_DISPLAY (display);
+  GHashTableIter iter;
+  gchar *value;
+
+  g_return_val_if_fail (GDK_IS_WAYLAND_DISPLAY (display), FALSE);
+  g_return_val_if_fail (interface != NULL, FALSE);
+
+  g_hash_table_iter_init (&iter, display_wayland->known_globals);
+
+  while (g_hash_table_iter_next (&iter, NULL, (gpointer*) &value))
+    {
+      if (strcmp (value, interface) == 0)
+        return TRUE;
+    }
+
+  return FALSE;
+}
diff --git a/gdk/wayland/gdkwaylanddisplay.h b/gdk/wayland/gdkwaylanddisplay.h
index d980d6cf87..af9cc896be 100644
--- a/gdk/wayland/gdkwaylanddisplay.h
+++ b/gdk/wayland/gdkwaylanddisplay.h
@@ -60,6 +60,10 @@ void                    gdk_wayland_display_set_startup_notification_id (GdkDisp
 GDK_AVAILABLE_IN_3_22
 gboolean                gdk_wayland_display_prefers_ssd         (GdkDisplay *display);
 
+GDK_AVAILABLE_IN_3_22
+gboolean                gdk_wayland_display_query_registry      (GdkDisplay  *display,
+                                                                const gchar *global);
+
 G_END_DECLS
 
 #endif /* __GDK_WAYLAND_DISPLAY_H__ */