[gtksourceview] sourceview: remove use of deprecated pango_find_base_dir()

[Christian Hergert <chergert src gnome org>]

commit 6ff0a0cdf88546e57ea04c2ea55167157cc655be
Author: Christian Hergert <chergert redhat com>
Date:   Thu Apr 25 21:36:48 2019 -0700

    sourceview: remove use of deprecated pango_find_base_dir()
    
    The pango_find_base_dir() requires retriving the line text up front and
    then passing that to pango (who in turn passes it to fribidi). The various
    pango functions for this are deprecated as we should be using fribidi
    directly going forward.

 gtksourceview/gtksourceview.c | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)
---
diff --git a/gtksourceview/gtksourceview.c b/gtksourceview/gtksourceview.c
index 328fbb20..a1fa0ceb 100644
--- a/gtksourceview/gtksourceview.c
+++ b/gtksourceview/gtksourceview.c
@@ -28,6 +28,7 @@
 #include "gtksourceview.h"
 
 #include <string.h> /* For strlen */
+#include <fribidi.h>
 #include <gtk/gtk.h>
 #include <gdk/gdkkeysyms.h>
 #include <pango/pango-tabs.h>
@@ -2101,6 +2102,7 @@ move_cursor_words (GtkTextView *text_view,
        GtkTextIter newplace;
        GtkTextIter line_start;
        GtkTextIter line_end;
+       const gchar *ptr;
        gchar *line_text;
 
        buffer = gtk_text_view_get_buffer (text_view);
@@ -2119,10 +2121,26 @@ move_cursor_words (GtkTextView *text_view,
        /* Swap direction for RTL to maintain visual cursor movement.
         * Otherwise, cursor will move in opposite direction which is counter
         * intuitve and causes confusion for RTL users.
+        *
+        * You would think we could iterate using the textiter, but we cannot
+        * since there is no way in GtkTextIter to check if it is visible (as
+        * that is not exposed by GtkTextBTree). So we use the allocated string
+        * contents instead.
         */
-       if (pango_find_base_dir (line_text, -1) == PANGO_DIRECTION_RTL)
+       for (ptr = line_text; *ptr; ptr = g_utf8_next_char (ptr))
        {
-               count *= -1;
+               gunichar ch = g_utf8_get_char (ptr);
+               FriBidiCharType ch_type = fribidi_get_bidi_type (ch);
+
+               if (FRIBIDI_IS_STRONG (ch_type))
+               {
+                       if (FRIBIDI_IS_RTL (ch_type))
+                       {
+                               count *= -1;
+                       }
+
+                       break;
+               }
        }
 
        g_free (line_text);