Fix the row number mistakenly reported by pos_visible_p in rare cases.

 src/xdisp.c (pos_visible_p): Properly save and restore the iterator
 state around the call to line_bottom, since it can move the
 iterator to another screen line.  This fixes off-by-one errors in
 the reported row in some rare cases.

diff --git a/src/ChangeLog b/src/ChangeLog
index e834a2cc1612cb669f27b37eaddf9cfd44d326cf..274817d82622bdd366c17d06a925fcbef50387e6 100644 (file)
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,10 @@
+2014-09-09  Eli Zaretskii  <eliz@gnu.org>
+
+       * xdisp.c (pos_visible_p): Properly save and restore the iterator
+       state around the call to line_bottom, since it can move the
+       iterator to another screen line.  This fixes off-by-one errors in
+       the reported row in some rare cases.
+
 2014-09-07  Eli Zaretskii  <eliz@gnu.org>
 
        * dispnew.c (prepare_desired_row): When MODE_LINE_P is zero,

diff --git a/src/xdisp.c b/src/xdisp.c
index d435bf148a0492f7ac83976e618d11772d29926e..6991e44b931c4ad5e87e05d782d8aff9af9b584f 100644 (file)
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -1452,11 +1452,15 @@ pos_visible_p (struct window *w, ptrdiff_t charpos, int *x, int *y,
         glyph.  */
       int top_x = it.current_x;
       int top_y = it.current_y;
-      /* Calling line_bottom_y may change it.method, it.position, etc.  */
-      enum it_method it_method = it.method;
-      int bottom_y = (last_height = 0, line_bottom_y (&it));
       int window_top_y = WINDOW_HEADER_LINE_HEIGHT (w);
+      int bottom_y;
+      struct it save_it;
+      void *save_it_data = NULL;
 
+      /* Calling line_bottom_y may change it.method, it.position, etc.  */
+      SAVE_IT (save_it, it, save_it_data);
+      last_height = 0;
+      bottom_y = line_bottom_y (&it);
       if (top_y < window_top_y)
        visible_p = bottom_y > window_top_y;
       else if (top_y < it.last_visible_y)
@@ -1473,7 +1477,6 @@ pos_visible_p (struct window *w, ptrdiff_t charpos, int *x, int *y,
             move_it_to again with a slightly larger vertical limit,
             and see if it actually moved vertically; if it did, we
             didn't really reach CHARPOS, which is beyond window end.  */
-         struct it save_it = it;
          /* Why 10? because we don't know how many canonical lines
             will the height of the next line(s) be.  So we guess.  */
          int ten_more_lines = 10 * default_line_pixel_height (w);
@@ -1483,11 +1486,11 @@ pos_visible_p (struct window *w, ptrdiff_t charpos, int *x, int *y,
          if (it.current_y > top_y)
            visible_p = 0;
 
-         it = save_it;
        }
+      RESTORE_IT (&it, &save_it, save_it_data);
       if (visible_p)
        {
-         if (it_method == GET_FROM_DISPLAY_VECTOR)
+         if (it.method == GET_FROM_DISPLAY_VECTOR)
            {
              /* We stopped on the last glyph of a display vector.
                 Try and recompute.  Hack alert!  */