[gtk/wip/chergert/spellcheck] use keymap to get defaults

[Christian Hergert <chergert src gnome org>]

commit 7e222c20126009bc308c1c4cf1b7da4a837349d0
Author: Christian Hergert <chergert redhat com>
Date:   Thu Mar 11 20:03:00 2021 -0800

    use keymap to get defaults
    
    the idea here is that per-windowing backends can provide specific
    languages supported such as xkb, etc

 gdk/gdkkeys.c          | 13 ++++++++++++-
 gdk/gdkkeysprivate.h   |  4 ++++
 gtk/gtkspellchecker.h  |  1 -
 gtk/gtkspelllanguage.c | 12 +++++++++++-
 4 files changed, 27 insertions(+), 3 deletions(-)
---
diff --git a/gdk/gdkkeys.c b/gdk/gdkkeys.c
index 90f42c5472..94985f53de 100644
--- a/gdk/gdkkeys.c
+++ b/gdk/gdkkeys.c
@@ -587,7 +587,7 @@ gdk_keymap_lookup_key (GdkKeymap          *keymap,
  *     (state & ~consumed & ALL_ACCELS_MASK) == GDK_CONTROL_MASK)
  *   // Control was pressed
  * ]|
- * 
+ *
  * An older interpretation @consumed_modifiers was that it contained
  * all modifiers that might affect the translation of the key;
  * this allowed accelerators to be stored with irrelevant consumed
@@ -814,3 +814,14 @@ gdk_keyval_convert_case (guint symbol,
   if (upper)
     *upper = xupper;
 }
+
+const char * const *
+gdk_keymap_get_languages (GdkKeymap *keymap)
+{
+  g_return_val_if_fail (GDK_IS_KEYMAP (keymap), NULL);
+
+  if (GDK_KEYMAP_GET_CLASS (keymap)->get_languages)
+    return GDK_KEYMAP_GET_CLASS (keymap)->get_languages (keymap);
+
+  return NULL;
+}
diff --git a/gdk/gdkkeysprivate.h b/gdk/gdkkeysprivate.h
index db05785678..f910d3258a 100644
--- a/gdk/gdkkeysprivate.h
+++ b/gdk/gdkkeysprivate.h
@@ -60,6 +60,7 @@ struct _GdkKeymapClass
                                          int             *level,
                                          GdkModifierType *consumed_modifiers);
   guint (* get_modifier_state)          (GdkKeymap *keymap);
+  const char * const * (* get_languages) (GdkKeymap *keymap);
 
 
   /* Signals */
@@ -121,6 +122,9 @@ void           gdk_keymap_get_cached_entries_for_keyval (GdkKeymap     *keymap,
                                                          GdkKeymapKey **keys,
                                                          guint         *n_keys);
 
+const char * const *
+               gdk_keymap_get_languages            (GdkKeymap          *keymap);
+
 G_END_DECLS
 
 #endif
diff --git a/gtk/gtkspellchecker.h b/gtk/gtkspellchecker.h
index 356b29b414..122ff2c1b0 100644
--- a/gtk/gtkspellchecker.h
+++ b/gtk/gtkspellchecker.h
@@ -64,7 +64,6 @@ void                gtk_spell_checker_set_correction    (GtkSpellChecker    *sel
                                                          const char         *correction,
                                                          gssize              correction_length);
 
-
 G_END_DECLS
 
 #endif /* __GTK_SPELL_CHECKER_H__ */
diff --git a/gtk/gtkspelllanguage.c b/gtk/gtkspelllanguage.c
index 350886ec24..432252021e 100644
--- a/gtk/gtkspelllanguage.c
+++ b/gtk/gtkspelllanguage.c
@@ -19,6 +19,9 @@
 
 #include "config.h"
 
+#include <gdk/gdkdisplayprivate.h>
+#include <gdk/gdkkeysprivate.h>
+
 #include "gtkspelllanguageprivate.h"
 
 struct _GtkSpellLanguage
@@ -142,7 +145,14 @@ _gtk_spell_language_get_defaults (void)
 
   if (defaults == NULL)
     {
-      /* TODO: guess defaults */
+      GdkDisplay *display = gdk_display_get_default ();
+      GdkKeymap *keymap = gdk_display_get_keymap (display);
+      const char * const *languages = gdk_keymap_get_languages (keymap);
+
+      if (languages == NULL || languages[0] == NULL)
+        languages = g_get_language_names ();
+
+      defaults = g_strdupv ((char **)languages);
     }
 
   return (const char * const *)defaults;