[gnome-builder] buffers: remove trailing ".in" when guessing language

[Christian Hergert <chergert src gnome org>]

commit 59e1a00e9a00796036cb1add76b031cdbdca36f3
Author: Christian Hergert <chergert redhat com>
Date:   Tue Oct 23 13:14:24 2018 -0700

    buffers: remove trailing ".in" when guessing language
    
    When guessing the language from GtkSourceView, we can remove the trailing
    .in so that we are more likely to get the proper language type. This is
    useful because rarely are people simply caring about the template expansion
    and more interested in the underlying language syntax.
    
    Fixes #681

 src/libide/buffers/ide-buffer-manager.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)
---
diff --git a/src/libide/buffers/ide-buffer-manager.c b/src/libide/buffers/ide-buffer-manager.c
index 2f37d38e9..a83d6c858 100644
--- a/src/libide/buffers/ide-buffer-manager.c
+++ b/src/libide/buffers/ide-buffer-manager.c
@@ -456,9 +456,11 @@ ide_buffer_manager_load_file__load_cb (GObject      *object,
   g_autoptr(IdeTask) task = user_data;
   g_autofree gchar *guess_contents = NULL;
   g_autofree gchar *content_type = NULL;
+  g_autofree gchar *truncated = NULL;
   GtkSourceFileLoader *loader = (GtkSourceFileLoader *)object;
   IdeBufferManager *self;
   const gchar *path;
+  const gchar *dot;
   IdeContext *context;
   LoadState *state;
   GtkTextIter iter;
@@ -540,8 +542,15 @@ ide_buffer_manager_load_file__load_cb (GObject      *object,
   gtk_text_iter_forward_chars (&end, 1024);
   guess_contents = gtk_text_iter_get_slice (&iter, &end);
   path = ide_file_get_path (state->file);
-  content_type = g_content_type_guess (path, (const guchar *)guess_contents,
-                                       strlen (guess_contents), &uncertain);
+
+  /* Remove the ".in" suffix for files that are expanded at build time. */
+  if ((dot = strrchr (path, '.')))
+    path = truncated = g_strndup (path, dot - path);
+
+  content_type = g_content_type_guess (path,
+                                       (const guchar *)guess_contents,
+                                       strlen (guess_contents),
+                                       &uncertain);
   if (content_type && !uncertain)
     _ide_file_set_content_type (state->file, content_type);