Fix bidi-aware cursor motion inside indentation.

 src/xdisp.c (Fcurrent_bidi_paragraph_direction): Fix search for previous
 non-empty line.  Fixes confusing cursor motion with arrow keys at
 the beginning of a line that starts with whitespace.

2 files changed, 20 insertions, 16 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index f0b1ecc3caa..17b53216e83 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -5,6 +5,9 @@
         (find_row_edges): If the row ends in a newline from a display
         string, increment its MATRIX_ROW_END_CHARPOS by one.  (Bug#9549)
         Handle the case of a display string with multiple newlines.
+        (Fcurrent_bidi_paragraph_direction): Fix search for previous
+        non-empty line.  Fixes confusing cursor motion with arrow keys at
+        the beginning of a line that starts with whitespace.
 
 2011-09-19  Lars Magne Ingebrigtsen  <larsi@gnus.org>
 
diff --git a/src/xdisp.c b/src/xdisp.c
index 81cba29206a..3505d18d502 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -19205,6 +19205,7 @@ See also `bidi-paragraph-direction'.  */)
       EMACS_INT pos = BUF_PT (buf);
       EMACS_INT bytepos = BUF_PT_BYTE (buf);
       int c;
+      void *itb_data = bidi_shelve_cache ();
 
       set_buffer_temp (buf);
       /* bidi_paragraph_init finds the base direction of the paragraph
@@ -19217,27 +19218,27 @@ See also `bidi-paragraph-direction'.  */)
           pos--;
           bytepos = CHAR_TO_BYTE (pos);
         }
-      while ((c = FETCH_BYTE (bytepos)) == '\n'
-             || c == ' ' || c == '\t' || c == '\f')
+      if (fast_looking_at (build_string ("[\f\t ]*\n"),
+                           pos, bytepos, ZV, ZV_BYTE, Qnil) > 0)
         {
-          if (bytepos <= BEGV_BYTE)
-            break;
-          bytepos--;
-          pos--;
+          while ((c = FETCH_BYTE (bytepos)) == '\n'
+                 || c == ' ' || c == '\t' || c == '\f')
+            {
+              if (bytepos <= BEGV_BYTE)
+                break;
+              bytepos--;
+              pos--;
+            }
+          while (!CHAR_HEAD_P (FETCH_BYTE (bytepos)))
+            bytepos--;
         }
-      while (!CHAR_HEAD_P (FETCH_BYTE (bytepos)))
-        bytepos--;
-      itb.charpos = pos;
-      itb.bytepos = bytepos;
-      itb.nchars = -1;
+      bidi_init_it (pos, bytepos, FRAME_WINDOW_P (SELECTED_FRAME ()), &itb);
       itb.string.s = NULL;
       itb.string.lstring = Qnil;
-      itb.frame_window_p = FRAME_WINDOW_P (SELECTED_FRAME ()); /* guesswork */
-      itb.first_elt = 1;
-      itb.separator_limit = -1;
-      itb.paragraph_dir = NEUTRAL_DIR;
-
+      itb.string.bufpos = 0;
+      itb.string.unibyte = 0;
       bidi_paragraph_init (NEUTRAL_DIR, &itb, 1);
+      bidi_unshelve_cache (itb_data, 0);
       set_buffer_temp (old);
       switch (itb.paragraph_dir)
         {