[gnome-builder] c-indenter: use tabs vs spaces handling from xml indenter

[Christian Hergert <chergert src gnome org>]

commit 208a959cd20e4cd96d7c9f409e55e7fcec2edf03
Author: Christian Hergert <chergert redhat com>
Date:   Wed Aug 31 12:52:33 2016 -0700

    c-indenter: use tabs vs spaces handling from xml indenter
    
    This uses a similar tabs vs spaces replacement strategy as what we have in
    the xml indenter.

 plugins/c-pack/ide-c-indenter.c |   46 ++++++++++++++++++++++++++++++++------
 1 files changed, 38 insertions(+), 8 deletions(-)
---
diff --git a/plugins/c-pack/ide-c-indenter.c b/plugins/c-pack/ide-c-indenter.c
index f47b09f..9b3fb2f 100644
--- a/plugins/c-pack/ide-c-indenter.c
+++ b/plugins/c-pack/ide-c-indenter.c
@@ -43,6 +43,10 @@ struct _IdeCIndenter
   gint           directive_indent;
   gint           extra_label_indent;
   gint           case_indent;
+
+  guint          tab_width;
+  guint          indent_width;
+  guint          use_tabs : 1;
 };
 
 static void indenter_iface_init (IdeIndenterInterface *iface);
@@ -102,18 +106,30 @@ build_indent (IdeCIndenter *c,
   while (str->len < line_offset)
     g_string_append_c (str, ' ');
 
-  if (!gtk_source_view_get_insert_spaces_instead_of_tabs (view) && (str->len >= tab_width))
+  if (c->use_tabs)
     {
-      guint n_tabs = str->len / tab_width;
-      guint n_spaces = str->len % tab_width;
+      GString *translated = g_string_new (NULL);
+      const gchar *pos = str->str;
+      const gchar *tab;
+      gchar *needle;
 
-      g_string_truncate (str, 0);
+      needle = g_malloc (c->tab_width + 1);
+      memset (needle, ' ', c->tab_width);
+      needle [c->tab_width] = '\0';
+
+      while (NULL != (tab = strstr (pos, needle)))
+        {
+          g_string_append_len (translated, pos, tab - pos);
+          g_string_append_c (translated, '\t');
+          pos = tab + c->tab_width;
+        }
 
-      for (i = 0; i < n_tabs; i++)
-        g_string_append (str, "\t");
+      if (*pos)
+        g_string_append (translated, pos);
 
-      for (i = 0; i < n_spaces; i++)
-        g_string_append (str, " ");
+      g_string_truncate (str, 0);
+      g_string_append_len (str, translated->str, translated->len);
+      g_string_free (translated, TRUE);
     }
 }
 
@@ -1278,6 +1294,8 @@ ide_c_indenter_format (IdeIndenter    *indenter,
   GtkTextIter begin_copy;
   gchar *ret = NULL;
   GtkTextBuffer *buffer;
+  guint tab_width = 2;
+  gint indent_width = -1;
 
   g_return_val_if_fail (IDE_IS_C_INDENTER (c), NULL);
   g_return_val_if_fail (IDE_IS_SOURCE_VIEW (view), NULL);
@@ -1286,6 +1304,18 @@ ide_c_indenter_format (IdeIndenter    *indenter,
 
   c->view = IDE_SOURCE_VIEW (view);
 
+  if (GTK_SOURCE_IS_VIEW (view))
+    {
+      tab_width = gtk_source_view_get_tab_width (GTK_SOURCE_VIEW (view));
+      indent_width = gtk_source_view_get_indent_width (GTK_SOURCE_VIEW (view));
+      if (indent_width != -1)
+        tab_width = indent_width;
+    }
+
+  c->tab_width = tab_width;
+  c->indent_width = (indent_width <= 0) ? tab_width : indent_width;
+  c->use_tabs = !gtk_source_view_get_insert_spaces_instead_of_tabs (GTK_SOURCE_VIEW (view));
+
   switch (event->keyval) {
   case GDK_KEY_Return:
   case GDK_KEY_KP_Enter: