[gnome-builder] file: add ide_file_get_language_id() helper

[Christian Hergert <chergert src gnome org>]

commit 84457d9ac626d10565728f30094992579a283aea
Author: Christian Hergert <chergert redhat com>
Date:   Thu Mar 30 20:44:11 2017 -0600

    file: add ide_file_get_language_id() helper
    
    Convenience to avoid having to do this all over the place.

 libide/files/ide-file.c |   15 +++++++++++++++
 libide/files/ide-file.h |    1 +
 2 files changed, 16 insertions(+), 0 deletions(-)
---
diff --git a/libide/files/ide-file.c b/libide/files/ide-file.c
index d141129..bd7e0b0 100644
--- a/libide/files/ide-file.c
+++ b/libide/files/ide-file.c
@@ -705,3 +705,18 @@ ide_file_compare (const IdeFile *a,
 
   return g_strcmp0 (filea, fileb);
 }
+
+const gchar *
+ide_file_get_language_id (IdeFile *self)
+{
+  GtkSourceLanguage *language;
+
+  g_return_val_if_fail (IDE_IS_FILE (self), NULL);
+
+  language = ide_file_get_language (self);
+
+  if (language != NULL)
+    return gtk_source_language_get_id (language);
+
+  return NULL;
+}
diff --git a/libide/files/ide-file.h b/libide/files/ide-file.h
index 6795218..3260cc6 100644
--- a/libide/files/ide-file.h
+++ b/libide/files/ide-file.h
@@ -36,6 +36,7 @@ IdeFile           *ide_file_new_for_path         (IdeContext           *context,
 gboolean           ide_file_get_is_temporary     (IdeFile              *self);
 guint              ide_file_get_temporary_id     (IdeFile              *self);
 GtkSourceLanguage *ide_file_get_language         (IdeFile              *self);
+const gchar       *ide_file_get_language_id      (IdeFile              *self);
 GFile             *ide_file_get_file             (IdeFile              *self);
 guint              ide_file_hash                 (IdeFile              *self);
 gboolean           ide_file_equal                (IdeFile              *self,