[gtksourceview] Better default candidate encodings, with translations

[Sébastien Wilmet <swilmet src gnome org>]

commit fc67d8c2c815674e9fa67cf278e8aed2b7fc6d46
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Tue Jul 29 14:33:33 2014 +0200

    Better default candidate encodings, with translations
    
    The translations are available in gedit. It is something difficult to
    translate, so it's better to move that in GtkSourceView.
    
    There is a new public function in GtkSourceEncoding to get the default
    candidates. The FileLoader uses by default that list, and adds the
    GtkSourceFile's encoding if it has been set by a previous file loading
    or saving operation. The file's encoding is added to the beginning of
    the list.

 gtksourceview/gtksourceencoding.c   |   42 ++++++++++++++++++++++++++++-
 gtksourceview/gtksourceencoding.h   |    7 +++-
 gtksourceview/gtksourcefile.c       |   15 +++++++++-
 gtksourceview/gtksourcefile.h       |    3 ++
 gtksourceview/gtksourcefileloader.c |   51 ++++++++++++++++++++++++++++++----
 5 files changed, 108 insertions(+), 10 deletions(-)
---
diff --git a/gtksourceview/gtksourceencoding.c b/gtksourceview/gtksourceencoding.c
index 211c28b..870a4b6 100644
--- a/gtksourceview/gtksourceencoding.c
+++ b/gtksourceview/gtksourceencoding.c
@@ -488,6 +488,46 @@ gtk_source_encoding_get_name (const GtkSourceEncoding* enc)
 }
 
 /**
+ * gtk_source_encoding_get_default_candidates:
+ *
+ * Returns: (transfer container) (element-type GtkSource.Encoding): the list of
+ * default candidates encodings. Free with g_slist_free().
+ */
+GSList *
+gtk_source_encoding_get_default_candidates (void)
+{
+       const gchar *encodings_str;
+       GVariant *encodings_variant;
+       const gchar **encodings_strv;
+       GSList *encodings_list;
+
+       /* Translators: This is the sorted list of encodings used by
+        * GtkSourceView for automatic detection of the file encoding. You may
+        * want to customize it adding encodings that are common in your
+        * country, for instance the GB18030 encoding for the Chinese
+        * translation. You may also want to remove the ISO-8859-15 encoding
+        * (covering English and most Western European languages) if you think
+        * people in your country will rarely use it.  "CURRENT" is a magic
+        * value used by gedit and it represents the encoding for the current
+        * locale, so please don't translate the "CURRENT" term.  Only
+        * recognized encodings are used. See
+        * https://git.gnome.org/browse/gtksourceview/tree/gtksourceview/gtksourceencoding.c#n147
+        * for a list of supported encodings.
+        */
+       encodings_str = _("['UTF-8', 'CURRENT', 'ISO-8859-15', 'UTF-16']");
+
+       encodings_variant = g_variant_new_parsed (encodings_str);
+       g_variant_ref_sink (encodings_variant);
+
+       encodings_strv = g_variant_get_strv (encodings_variant, NULL);
+
+       encodings_list = _gtk_source_encoding_strv_to_list (encodings_strv);
+
+       g_variant_unref (encodings_variant);
+       return encodings_list;
+}
+
+/**
  * gtk_source_encoding_copy:
  * @enc: a #GtkSourceEncoding.
  *
@@ -518,7 +558,6 @@ gtk_source_encoding_free (GtkSourceEncoding *enc)
        g_return_if_fail (enc != NULL);
 }
 
-#if 0
 /* Will probably be used in the future. */
 static gboolean
 data_exists (GSList         *list,
@@ -564,6 +603,7 @@ _gtk_source_encoding_strv_to_list (const gchar * const *enc_str)
        return g_slist_reverse (res);
 }
 
+#if 0
 gchar **
 _gtk_source_encoding_list_to_strv (const GSList *enc_list)
 {
diff --git a/gtksourceview/gtksourceencoding.h b/gtksourceview/gtksourceencoding.h
index 260dfbb..2567e3e 100644
--- a/gtksourceview/gtksourceencoding.h
+++ b/gtksourceview/gtksourceencoding.h
@@ -60,15 +60,18 @@ const GtkSourceEncoding     *gtk_source_encoding_get_current        (void);
 void                    gtk_source_encoding_foreach            (GtkSourceEncodingForeachFunc func,
                                                                 gpointer                     user_data);
 
+GSList                 *gtk_source_encoding_get_default_candidates
+                                                               (void);
+
 /* These should not be used, they are just to make python bindings happy */
 GtkSourceEncoding      *gtk_source_encoding_copy               (const GtkSourceEncoding *enc);
 void                    gtk_source_encoding_free               (GtkSourceEncoding       *enc);
 
-#if 0
-/* Will probably be used in the future. */
 G_GNUC_INTERNAL
 GSList                 *_gtk_source_encoding_strv_to_list      (const gchar * const     *enc_str);
 
+#if 0
+/* Will probably be used in the future. */
 G_GNUC_INTERNAL
 gchar                 **_gtk_source_encoding_list_to_strv      (const GSList            *enc);
 #endif
diff --git a/gtksourceview/gtksourcefile.c b/gtksourceview/gtksourcefile.c
index 98b0415..d889676 100644
--- a/gtksourceview/gtksourcefile.c
+++ b/gtksourceview/gtksourcefile.c
@@ -65,6 +65,9 @@ struct _GtkSourceFilePrivate
        GTimeVal modification_time;
 
        guint modification_time_set : 1;
+
+       /* TRUE if the encoding has been set by a FileLoader or a FileSaver. */
+       guint encoding_set : 1;
 };
 
 G_DEFINE_TYPE_WITH_PRIVATE (GtkSourceFile, gtk_source_file, G_TYPE_OBJECT)
@@ -173,7 +176,7 @@ gtk_source_file_class_init (GtkSourceFileClass *klass)
        /**
         * GtkSourceFile:encoding:
         *
-        * The character encoding.
+        * The character encoding. UTF-8 by default.
         *
         * Since: 3.14
         */
@@ -227,6 +230,7 @@ gtk_source_file_init (GtkSourceFile *file)
        file->priv = gtk_source_file_get_instance_private (file);
 
        file->priv->encoding = gtk_source_encoding_get_utf8 ();
+       file->priv->encoding_set = FALSE;
 }
 
 /**
@@ -295,6 +299,8 @@ _gtk_source_file_set_encoding (GtkSourceFile           *file,
 {
        g_return_if_fail (GTK_SOURCE_IS_FILE (file));
 
+       file->priv->encoding_set = TRUE;
+
        if (encoding == NULL)
        {
                encoding = gtk_source_encoding_get_utf8 ();
@@ -307,6 +313,13 @@ _gtk_source_file_set_encoding (GtkSourceFile           *file,
        }
 }
 
+/* Returns TRUE if the encoding has been set by a FileLoader or a FileSaver. */
+gboolean
+_gtk_source_file_is_encoding_set (GtkSourceFile *file)
+{
+       return file->priv->encoding_set;
+}
+
 /**
  * gtk_source_file_get_encoding:
  * @file: a #GtkSourceFile.
diff --git a/gtksourceview/gtksourcefile.h b/gtksourceview/gtksourcefile.h
index e4859f1..922eb6b 100644
--- a/gtksourceview/gtksourcefile.h
+++ b/gtksourceview/gtksourcefile.h
@@ -92,6 +92,9 @@ void           _gtk_source_file_set_encoding                  (GtkSourceFile           
*file,
                                                                 const GtkSourceEncoding *encoding);
 
 G_GNUC_INTERNAL
+gboolean        _gtk_source_file_is_encoding_set               (GtkSourceFile *file);
+
+G_GNUC_INTERNAL
 void            _gtk_source_file_set_newline_type              (GtkSourceFile        *file,
                                                                 GtkSourceNewlineType  newline_type);
 
diff --git a/gtksourceview/gtksourcefileloader.c b/gtksourceview/gtksourcefileloader.c
index be2c24f..f297a9e 100644
--- a/gtksourceview/gtksourcefileloader.c
+++ b/gtksourceview/gtksourcefileloader.c
@@ -259,18 +259,57 @@ gtk_source_file_loader_dispose (GObject *object)
 }
 
 static void
+set_default_candidate_encodings (GtkSourceFileLoader *loader)
+{
+       GSList *list;
+       GSList *l;
+       const GtkSourceEncoding *file_encoding;
+
+       /* Get first the default candidates from GtkSourceEncoding. If the
+        * GtkSourceFile's encoding has been set by a FileLoader or FileSaver,
+        * put it at the beginning of the list.
+        */
+       list = gtk_source_encoding_get_default_candidates ();
+
+       if (loader->priv->file == NULL ||
+           !_gtk_source_file_is_encoding_set (loader->priv->file))
+       {
+               goto end;
+       }
+
+       file_encoding = gtk_source_file_get_encoding (loader->priv->file);
+
+       /* Remove file_encoding from the list, if already present, and prepend
+        * it to the list.
+        */
+       for (l = list; l != NULL; l = l->next)
+       {
+               const GtkSourceEncoding *cur_encoding = l->data;
+
+               if (cur_encoding == file_encoding)
+               {
+                       list = g_slist_delete_link (list, l);
+
+                       /* The list doesn't contain duplicates, normally. */
+                       break;
+               }
+       }
+
+       list = g_slist_prepend (list, (gpointer) file_encoding);
+
+end:
+       g_slist_free (loader->priv->candidate_encodings);
+       loader->priv->candidate_encodings = list;
+}
+
+static void
 gtk_source_file_loader_constructed (GObject *object)
 {
        GtkSourceFileLoader *loader = GTK_SOURCE_FILE_LOADER (object);
 
        if (loader->priv->file != NULL)
        {
-               const GtkSourceEncoding *encoding;
-
-               encoding = gtk_source_file_get_encoding (loader->priv->file);
-
-               g_slist_free (loader->priv->candidate_encodings);
-               loader->priv->candidate_encodings = g_slist_prepend (NULL, (gpointer) encoding);
+               set_default_candidate_encodings (loader);
 
                if (loader->priv->location == NULL &&
                    loader->priv->input_stream_property == NULL)