Completed initial debugging and testing of reimplemented cursor motion.

 .gdbinit (prowlims): Display row->minpos and row->maxpos.
 Display truncated_on_left_p and truncated_on_right_p flags.
 Formatting fixes.
 (pmtxrows): Display the ordinal number of each row.  Don't display
 rows beyond the last one.
 xdisp.c (RECORD_MAX_MIN_POS): New macro.
 (display_line): Use it to record the minimum and maximum buffer
 positions for glyphs in the row being assembled.  If word wrap is
 in effect, restore minimum and maximum positions seen up to the
 wrap point, when iterator returns to it.
 (find_row_edges): Fix logic; eol_pos should be tested before the
 rest.
 (try_window_reusing_current_matrix): Give up if in bidi-reordered
 row and cursor not already at point.  Restore original pre-bidi
 code for unidirectional buffers.
 bidi.c (bidi_cache_shrink, bidi_cache_iterator_state): Fix
 reallocation of the cache.  (Bug#6210)
 (bidi_cache_iterator_state): Don't zero out new_paragraph (it is
 not copied by bidi_copy_it).

4 files changed, 97 insertions, 94 deletions

diff --git a/src/.gdbinit b/src/.gdbinit
index 5ecdaa4a572..1fd7e288736 100644
--- a/src/.gdbinit
+++ b/src/.gdbinit
@@ -616,7 +616,7 @@ Pretty print all glyphs in it->glyph_row.
 end
 
 define prowlims
-  printf "start=%d,end=%d,reversed=%d,cont=%d,at_zv=%d\n", $arg0->start.pos.charpos, $arg0->end.pos.charpos, $arg0->reversed_p, $arg0->continued_p, $arg0->ends_at_zv_p
+  printf "edges=(%d,%d),r2l=%d,cont=%d,trunc=(%d,%d),at_zv=%d\n", $arg0->minpos.charpos, $arg0->maxpos.charpos, $arg0->reversed_p, $arg0->continued_p, $arg0->truncated_on_left_p, $arg0->truncated_on_right_p, $arg0->ends_at_zv_p
 end
 document prowlims
 Print important attributes of a glyph_row structure.
@@ -626,10 +626,13 @@ end
 define pmtxrows
   set $mtx = $arg0
   set $gl = $mtx->rows
-  set $glend = $mtx->rows + $mtx->nrows
+  set $glend = $mtx->rows + $mtx->nrows - 1
+  set $i = 0
   while ($gl < $glend)
+    printf "%d: ", $i
     prowlims $gl
     set $gl = $gl + 1
+    set $i = $i + 1
   end
 end
 document pmtxrows
diff --git a/src/ChangeLog b/src/ChangeLog
index fe30d07692a..1947f9598f0 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,27 @@
+2010-05-19  Eli Zaretskii  <eliz@gnu.org>
+
+        * .gdbinit (prowlims): Display row->minpos and row->maxpos.
+        Display truncated_on_left_p and truncated_on_right_p flags.
+        Formatting fixes.
+        (pmtxrows): Display the ordinal number of each row.  Don't display
+        rows beyond the last one.
+
+        * xdisp.c (RECORD_MAX_MIN_POS): New macro.
+        (display_line): Use it to record the minimum and maximum buffer
+        positions for glyphs in the row being assembled.  If word wrap is
+        in effect, restore minimum and maximum positions seen up to the
+        wrap point, when iterator returns to it.
+        (find_row_edges): Fix logic; eol_pos should be tested before the
+        rest.
+        (try_window_reusing_current_matrix): Give up if in bidi-reordered
+        row and cursor not already at point.  Restore original pre-bidi
+        code for unidirectional buffers.
+
+        * bidi.c (bidi_cache_shrink, bidi_cache_iterator_state): Fix
+        reallocation of the cache.  (Bug#6210)
+        (bidi_cache_iterator_state): Don't zero out new_paragraph (it is
+        not copied by bidi_copy_it).
+
 2010-05-18  Eli Zaretskii  <eliz@gnu.org>
 
         * dispextern.h (struct glyph_row): New members minpos and maxpos.
diff --git a/src/bidi.c b/src/bidi.c
index dbc95608fea..bdeccfee97c 100644
--- a/src/bidi.c
+++ b/src/bidi.c
@@ -543,6 +543,7 @@ bidi_copy_it (struct bidi_it *to, struct bidi_it *from)
 #define BIDI_CACHE_CHUNK 200
 static struct bidi_it *bidi_cache;
 static size_t bidi_cache_size = 0;
+static size_t elsz = sizeof (struct bidi_it);
 static int bidi_cache_idx;      /* next unused cache slot */
 static int bidi_cache_last_idx; /* slot of last cache hit */
 
@@ -558,8 +559,9 @@ bidi_cache_shrink (void)
 {
   if (bidi_cache_size > BIDI_CACHE_CHUNK)
     {
-      bidi_cache_size = BIDI_CACHE_CHUNK * sizeof (struct bidi_it);
-      bidi_cache = (struct bidi_it *) xrealloc (bidi_cache, bidi_cache_size);
+      bidi_cache_size = BIDI_CACHE_CHUNK;
+      bidi_cache =
+        (struct bidi_it *) xrealloc (bidi_cache, bidi_cache_size * elsz);
     }
   bidi_cache_reset ();
 }
@@ -688,9 +690,9 @@ bidi_cache_iterator_state (struct bidi_it *bidi_it, int resolved)
       /* Enlarge the cache as needed.  */
       if (idx >= bidi_cache_size)
         {
-          bidi_cache_size += BIDI_CACHE_CHUNK * sizeof (struct bidi_it);
+          bidi_cache_size += BIDI_CACHE_CHUNK;
           bidi_cache =
-            (struct bidi_it *) xrealloc (bidi_cache, bidi_cache_size);
+            (struct bidi_it *) xrealloc (bidi_cache, bidi_cache_size * elsz);
         }
       /* Character positions should correspond to cache positions 1:1.
          If we are outside the range of cached positions, the cache is
@@ -705,7 +707,6 @@ bidi_cache_iterator_state (struct bidi_it *bidi_it, int resolved)
       bidi_copy_it (&bidi_cache[idx], bidi_it);
       if (!resolved)
         bidi_cache[idx].resolved_level = -1;
-      bidi_cache[idx].new_paragraph = 0;
     }
   else
     {
diff --git a/src/xdisp.c b/src/xdisp.c
index 9cd562e8e3d..47c08d0df79 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -15293,39 +15293,26 @@ try_window_reusing_current_matrix (w)
             {
               struct glyph *glyph = row->glyphs[TEXT_AREA] + w->cursor.hpos;
               struct glyph *end = glyph + row->used[TEXT_AREA];
-              struct glyph *orig_glyph = glyph;
-              struct cursor_pos orig_cursor = w->cursor;
 
-              for (; glyph < end
-                     && (!BUFFERP (glyph->object)
-                         || glyph->charpos != PT);
-                   glyph++)
+              /* Can't use this optimization with bidi-reordered glyph
+                 rows, unless cursor is already at point. */
+              if (!NILP (XBUFFER (w->buffer)->bidi_display_reordering))
                 {
-                  w->cursor.hpos++;
-                  w->cursor.x += glyph->pixel_width;
-                }
-              /* With bidi reordering, charpos changes non-linearly
-                 with hpos, so the right glyph could be to the
-                 left.  */
-              if (!NILP (XBUFFER (w->buffer)->bidi_display_reordering)
-                  && (!BUFFERP (glyph->object) || glyph->charpos != PT))
-                {
-                  struct glyph *start_glyph = row->glyphs[TEXT_AREA];
-
-                  glyph = orig_glyph - 1;
-                  orig_cursor.hpos--;
-                  orig_cursor.x -= glyph->pixel_width;
-                  for (; glyph >= start_glyph
-                         && (!BUFFERP (glyph->object)
-                             || glyph->charpos != PT);
-                       glyph--)
-                    {
-                      w->cursor.hpos--;
-                      w->cursor.x -= glyph->pixel_width;
-                    }
-                  if (BUFFERP (glyph->object) && glyph->charpos == PT)
-                    w->cursor = orig_cursor;
+                  if (!(w->cursor.hpos >= 0
+                        && w->cursor.hpos < row->used[TEXT_AREA]
+                        && BUFFERP (glyph->object)
+                        && glyph->charpos == PT))
+                    return 0;
                 }
+              else
+                for (; glyph < end
+                       && (!BUFFERP (glyph->object)
+                           || glyph->charpos < PT);
+                     glyph++)
+                  {
+                    w->cursor.hpos++;
+                    w->cursor.x += glyph->pixel_width;
+                  }
             }
         }
 
@@ -17530,14 +17517,7 @@ find_row_edges (it, row, min_pos, min_bpos, max_pos, max_bpos)
   /* ROW->minpos is the value of min_pos, the minimal buffer position
      we have in ROW.  */
   if (min_pos <= ZV)
-    {
-      SET_TEXT_POS (row->minpos, min_pos, min_bpos);
-      if (max_pos == 0)
-        {
-          max_pos = min_pos;
-          max_bpos = min_bpos;
-        }
-    }
+    SET_TEXT_POS (row->minpos, min_pos, min_bpos);
   else
     {
       /* We didn't find _any_ valid buffer positions in any of the
@@ -17554,12 +17534,11 @@ find_row_edges (it, row, min_pos, min_bpos, max_pos, max_bpos)
   /* Here are the various use-cases for ending the row, and the
      corresponding values for ROW->maxpos:
 
-     Empty line                               min_pos + 1
      Line ends in a newline from buffer       eol_pos + 1
      Line is continued from buffer            max_pos + 1
      Line ends in a newline from string       max_pos
      Line is continued from string            max_pos
-     Line is entirely from a string           min_pos
+     Line is entirely from a string           min_pos == max_pos
      Line that ends at ZV                     ZV
 
      If you discover other use-cases, please add them here as
@@ -17568,16 +17547,7 @@ find_row_edges (it, row, min_pos, min_bpos, max_pos, max_bpos)
     row->maxpos = it->current.pos;
   else if (row->used[TEXT_AREA])
     {
-      if (max_pos == min_pos)
-        {
-          if (it->method == GET_FROM_BUFFER)
-            /* Empty line, which stands for a newline.  */
-            SET_TEXT_POS (row->maxpos, min_pos + 1, min_bpos + 1);
-          else
-            /* A line that is entirely from a string.  */
-            row->maxpos = row->minpos;
-        }
-      else if (CHARPOS (it->eol_pos) > 0)
+      if (CHARPOS (it->eol_pos) > 0)
         SET_TEXT_POS (row->maxpos,
                       CHARPOS (it->eol_pos) + 1, BYTEPOS (it->eol_pos) + 1);
       else if (row->continued_p)
@@ -17592,6 +17562,9 @@ find_row_edges (it, row, min_pos, min_bpos, max_pos, max_bpos)
         }
       else if (row->ends_in_newline_from_string_p)
         SET_TEXT_POS (row->maxpos, max_pos, max_bpos);
+      else if (max_pos == min_pos && it->method != GET_FROM_BUFFER)
+        /* A line that is entirely from a string/image/stretch...  */
+        row->maxpos = row->minpos;
       else
         abort ();
     }
@@ -17616,6 +17589,8 @@ display_line (it)
   int wrap_row_used = -1, wrap_row_ascent, wrap_row_height;
   int wrap_row_phys_ascent, wrap_row_phys_height;
   int wrap_row_extra_line_spacing;
+  EMACS_INT wrap_row_min_pos, wrap_row_min_bpos;
+  EMACS_INT wrap_row_max_pos, wrap_row_max_bpos;
   int cvpos;
   EMACS_INT min_pos = ZV + 1, min_bpos, max_pos = 0, max_bpos;
 
@@ -17674,6 +17649,23 @@ display_line (it)
   row->phys_height = it->max_phys_ascent + it->max_phys_descent;
   row->extra_line_spacing = it->max_extra_line_spacing;
 
+/* Utility macro to record max and min buffer positions seen until now.  */
+#define RECORD_MAX_MIN_POS(IT)                                  \
+  do                                                            \
+    {                                                           \
+      if (IT_CHARPOS (*(IT)) < min_pos)                         \
+        {                                                       \
+          min_pos = IT_CHARPOS (*(IT));                         \
+          min_bpos = IT_BYTEPOS (*(IT));                        \
+        }                                                       \
+      if (IT_CHARPOS (*(IT)) > max_pos)                         \
+        {                                                       \
+          max_pos = IT_CHARPOS (*(IT));                         \
+          max_bpos = IT_BYTEPOS (*(IT));                        \
+        }                                                       \
+    }                                                           \
+  while (0)
+
   /* Loop generating characters.  The loop is left with IT on the next
      character to display.  */
   while (1)
@@ -17743,6 +17735,10 @@ display_line (it)
                   wrap_row_phys_ascent = row->phys_ascent;
                   wrap_row_phys_height = row->phys_height;
                   wrap_row_extra_line_spacing = row->extra_line_spacing;
+                  wrap_row_min_pos = min_pos;
+                  wrap_row_min_bpos = min_bpos;
+                  wrap_row_max_pos = max_pos;
+                  wrap_row_max_bpos = max_bpos;
                   may_wrap = 0;
                 }
             }
@@ -17793,6 +17789,10 @@ display_line (it)
                                          it->max_extra_line_spacing);
           if (it->current_x - it->pixel_width < it->first_visible_x)
             row->x = x - it->first_visible_x;
+          /* Record the maximum and minimum buffer positions seen so
+             far in glyphs that will be displayed by this row.  */
+          if (it->bidi_p)
+            RECORD_MAX_MIN_POS (it);
         }
       else
         {
@@ -17826,6 +17826,11 @@ display_line (it)
                       it->current_x = new_x;
                       it->continuation_lines_width += new_x;
                       ++it->hpos;
+                      /* Record the maximum and minimum buffer
+                         positions seen so far in glyphs that will be
+                         displayed by this row.  */
+                      if (it->bidi_p)
+                        RECORD_MAX_MIN_POS (it);
                       if (i == nglyphs - 1)
                         {
                           /* If line-wrap is on, check if a previous
@@ -17857,27 +17862,6 @@ display_line (it)
                                 }
                             }
                         }
-
-                      /* Record the maximum and minimum buffer
-                         positions seen so far in glyphs that will be
-                         displayed by this row.  */
-                      if (it->bidi_p)
-                        {
-                          if (BUFFERP (glyph->object)
-                              || INTEGERP (glyph->object))
-                            {
-                              if (IT_CHARPOS (*it) < min_pos)
-                                {
-                                  min_pos = IT_CHARPOS (*it);
-                                  min_bpos = IT_BYTEPOS (*it);
-                                }
-                              if (IT_CHARPOS (*it) > max_pos)
-                                {
-                                  max_pos = IT_CHARPOS (*it);
-                                  max_bpos = IT_BYTEPOS (*it);
-                                }
-                            }
-                        }
                     }
                   else if (CHAR_GLYPH_PADDING_P (*glyph)
                            && !FRAME_WINDOW_P (it->f))
@@ -17921,6 +17905,10 @@ display_line (it)
                       row->phys_ascent = wrap_row_phys_ascent;
                       row->phys_height = wrap_row_phys_height;
                       row->extra_line_spacing = wrap_row_extra_line_spacing;
+                      min_pos = wrap_row_min_pos;
+                      min_bpos = wrap_row_min_bpos;
+                      max_pos = wrap_row_max_pos;
+                      max_bpos = wrap_row_max_bpos;
                       row->continued_p = 1;
                       row->ends_at_zv_p = 0;
                       row->exact_window_width_line_p = 0;
@@ -17987,22 +17975,7 @@ display_line (it)
                      seen so far in glyphs that will be displayed by
                      this row.  */
                   if (it->bidi_p)
-                    {
-                      if (BUFFERP (glyph->object)
-                          || INTEGERP (glyph->object))
-                        {
-                          if (IT_CHARPOS (*it) < min_pos)
-                            {
-                              min_pos = IT_CHARPOS (*it);
-                              min_bpos = IT_BYTEPOS (*it);
-                            }
-                          if (IT_CHARPOS (*it) > max_pos)
-                            {
-                              max_pos = IT_CHARPOS (*it);
-                              max_bpos = IT_BYTEPOS (*it);
-                            }
-                        }
-                    }
+                    RECORD_MAX_MIN_POS (it);
 
                   if (x < it->first_visible_x)
                     /* Glyph is partially visible, i.e. row starts at
@@ -18261,6 +18234,8 @@ display_line (it)
     it->glyph_row->reversed_p = row->reversed_p;
   it->start = row->end;
   return row->displays_text_p;
+
+#undef RECORD_MAX_MIN_POS
 }
 
 DEFUN ("current-bidi-paragraph-direction", Fcurrent_bidi_paragraph_direction,