Fix excessive calls to bidi_shelve_cache reported in bug #15555.

 src/xdisp.c (move_it_in_display_line_to): Save the iterator state in ppos_it
 only once per call.  Reimplement the method used to return to the
 best candidate position if all the positions found in display line
 are beyond TO_CHARPOS.  This cuts down the number of calls to
 bidi_shelve_cache, which moves a lot of stuff when lines are long
 and include bidirectional text.

diff --git a/src/ChangeLog b/src/ChangeLog
index 3c063ca3c0b1fee26645e1ec5da7a3829ed36afc..4bb4719710672d12555d17fb7705fc921acebcb2 100644 (file)
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -5,6 +5,12 @@
        (try_cursor_movement): Don't use cursor position if
        set_cursor_from_row failed to compute it.  This avoids assertion
        violations in MATRIX_ROW.
+       (move_it_in_display_line_to): Save the iterator state in ppos_it
+       only once per call.  Reimplement the method used to return to the
+       best candidate position if all the positions found in display line
+       are beyond TO_CHARPOS.  This cuts down the number of calls to
+       bidi_shelve_cache, which moves a lot of stuff when lines are long
+       and include bidirectional text.  (Bug#15555)
 
 2014-02-20  Glenn Morris  <rgm@gnu.org>
 

diff --git a/src/xdisp.c b/src/xdisp.c
index 94dd65c5d0bb2a569b99f6ba5c5954469b7f255d..840ff1288e500f414941f7c61fbea2b0c728ddb5 100644 (file)
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -8313,7 +8313,7 @@ move_it_in_display_line_to (struct it *it,
   void *ppos_data = NULL;
   int may_wrap = 0;
   enum it_method prev_method = it->method;
-  ptrdiff_t prev_pos = IT_CHARPOS (*it);
+  ptrdiff_t closest_pos, prev_pos = IT_CHARPOS (*it);
   int saw_smaller_pos = prev_pos < to_charpos;
 
   /* Don't produce glyphs in produce_glyphs.  */
@@ -8330,16 +8330,21 @@ move_it_in_display_line_to (struct it *it,
   atx_it.sp = -1;
 
   /* Use ppos_it under bidi reordering to save a copy of IT for the
-     position > CHARPOS that is the closest to CHARPOS.  We restore
-     that position in IT when we have scanned the entire display line
-     without finding a match for CHARPOS and all the character
-     positions are greater than CHARPOS.  */
+     initial position.  We restore that position in IT when we have
+     scanned the entire display line without finding a match for
+     TO_CHARPOS and all the character positions are greater than
+     TO_CHARPOS.  We then restart the scan from the initial position,
+     and stop at CLOSEST_POS, which is a position > TO_CHARPOS that is
+     the closest to TO_CHARPOS.  */
   if (it->bidi_p)
     {
-      SAVE_IT (ppos_it, *it, ppos_data);
-      SET_TEXT_POS (ppos_it.current.pos, ZV, ZV_BYTE);
       if ((op & MOVE_TO_POS) && IT_CHARPOS (*it) >= to_charpos)
-       SAVE_IT (ppos_it, *it, ppos_data);
+       {
+         SAVE_IT (ppos_it, *it, ppos_data);
+         closest_pos = IT_CHARPOS (*it);
+       }
+      else
+       closest_pos = ZV;
     }
 
 #define BUFFER_POS_REACHED_P()                                 \
@@ -8483,8 +8488,8 @@ move_it_in_display_line_to (struct it *it,
          if (it->bidi_p
              && (op & MOVE_TO_POS)
              && IT_CHARPOS (*it) > to_charpos
-             && IT_CHARPOS (*it) < IT_CHARPOS (ppos_it))
-           SAVE_IT (ppos_it, *it, ppos_data);
+             && IT_CHARPOS (*it) < closest_pos)
+           closest_pos = IT_CHARPOS (*it);
          continue;
        }
 
@@ -8706,9 +8711,11 @@ move_it_in_display_line_to (struct it *it,
            {
              if (!saw_smaller_pos && IT_CHARPOS (*it) > to_charpos)
                {
-                 if (IT_CHARPOS (ppos_it) < ZV)
+                 if (closest_pos < ZV)
                    {
                      RESTORE_IT (it, &ppos_it, ppos_data);
+                     move_it_in_display_line_to (it, closest_pos, -1,
+                                                 MOVE_TO_POS);
                      result = MOVE_POS_MATCH_OR_ZV;
                    }
                  else
@@ -8738,8 +8745,8 @@ move_it_in_display_line_to (struct it *it,
       if (it->bidi_p
          && (op & MOVE_TO_POS)
          && IT_CHARPOS (*it) >= to_charpos
-         && IT_CHARPOS (*it) < IT_CHARPOS (ppos_it))
-       SAVE_IT (ppos_it, *it, ppos_data);
+         && IT_CHARPOS (*it) < closest_pos)
+       closest_pos = IT_CHARPOS (*it);
 
       /* Stop if lines are truncated and IT's current x-position is
         past the right edge of the window now.  */
@@ -8765,8 +8772,13 @@ move_it_in_display_line_to (struct it *it,
                      && IT_CHARPOS (*it) > to_charpos))
                {
                  if (it->bidi_p
-                     && !at_eob_p && IT_CHARPOS (ppos_it) < ZV)
-                   RESTORE_IT (it, &ppos_it, ppos_data);
+                     && !BUFFER_POS_REACHED_P ()
+                     && !at_eob_p && closest_pos < ZV)
+                   {
+                     RESTORE_IT (it, &ppos_it, ppos_data);
+                     move_it_in_display_line_to (it, closest_pos, -1,
+                                                 MOVE_TO_POS);
+                   }
                  result = MOVE_POS_MATCH_OR_ZV;
                  break;
                }
@@ -8780,8 +8792,11 @@ move_it_in_display_line_to (struct it *it,
                   && !saw_smaller_pos
                   && IT_CHARPOS (*it) > to_charpos)
            {
-             if (IT_CHARPOS (ppos_it) < ZV)
-               RESTORE_IT (it, &ppos_it, ppos_data);
+             if (closest_pos < ZV)
+               {
+                 RESTORE_IT (it, &ppos_it, ppos_data);
+                 move_it_in_display_line_to (it, closest_pos, -1, MOVE_TO_POS);
+               }
              result = MOVE_POS_MATCH_OR_ZV;
              break;
            }