* window.h (struct window): Change window_end_valid member from

Lisp_Object to a bitfield.  Adjust comments.
(wset_window_end_valid): Remove.
* window.c (adjust_window_count): Clear window_end_valid.
(Fwindow_end): Adjust user.  Remove ancient #if 0 code.
(Fwindow_line_height, set_window_buffer, Frecenter)
(Fsplit_window_internal, Fdelete_other_windows_internal)
(Fset_window_fringes, Fset_window_scroll_bars): Adjust users.
* dispnew.c (adjust_glyph_matrix, clear_window_matrices): Likewise.
* xdisp.c (check_window_end, reconsider_clip_changes)
(redisplay_internal, mark_window_display_accurate_1, redisplay_window)
(try_window, try_window_reusing_current_matrix, note_mouse_highlight)
(find_first_unchanged_at_end_row, try_window_id): Likewise.

5 files changed, 61 insertions, 59 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index ec7f8f068bd..7dc7b25f85a 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,21 @@
 2013-01-22  Dmitry Antipov  <dmantipov@yandex.ru>
 
+        * window.h (struct window): Change window_end_valid member from
+        Lisp_Object to a bitfield.  Adjust comments.
+        (wset_window_end_valid): Remove.
+        * window.c (adjust_window_count): Clear window_end_valid.
+        (Fwindow_end): Adjust user.  Remove ancient #if 0 code.
+        (Fwindow_line_height, set_window_buffer, Frecenter)
+        (Fsplit_window_internal, Fdelete_other_windows_internal)
+        (Fset_window_fringes, Fset_window_scroll_bars): Adjust users.
+        * dispnew.c (adjust_glyph_matrix, clear_window_matrices): Likewise.
+        * xdisp.c (check_window_end, reconsider_clip_changes)
+        (redisplay_internal, mark_window_display_accurate_1, redisplay_window)
+        (try_window, try_window_reusing_current_matrix, note_mouse_highlight)
+        (find_first_unchanged_at_end_row, try_window_id): Likewise.
+
+2013-01-22  Dmitry Antipov  <dmantipov@yandex.ru>
+
         * xdisp.c (mark_window_display_accurate): Simplify the loop
         assuming that the only one of vchild, hchild or buffer window
         slots is non-nil.  Call mark_window_display_accurate_1 for
diff --git a/src/dispnew.c b/src/dispnew.c
index 1e9d94f3789..0dba576e101 100644
--- a/src/dispnew.c
+++ b/src/dispnew.c
@@ -607,7 +607,7 @@ adjust_glyph_matrix (struct window *w, struct glyph_matrix *matrix, int x, int y
                  are invalidated below.  */
               if (INTEGERP (w->window_end_vpos)
                   && XFASTINT (w->window_end_vpos) >= i)
-                wset_window_end_valid (w, Qnil);
+                w->window_end_valid = 0;
 
               while (i < matrix->nrows)
                 matrix->rows[i++].enabled_p = 0;
@@ -862,7 +862,7 @@ clear_window_matrices (struct window *w, bool desired_p)
           else
             {
               clear_glyph_matrix (w->current_matrix);
-              wset_window_end_valid (w, Qnil);
+              w->window_end_valid = 0;
             }
         }
 
diff --git a/src/window.c b/src/window.c
index e60b9e8967d..db00bc26482 100644
--- a/src/window.c
+++ b/src/window.c
@@ -286,6 +286,8 @@ adjust_window_count (struct window *w, int arg)
         b = b->base_buffer;
       b->window_count += arg;
       eassert (b->window_count >= 0);
+      /* Catch redisplay's attention.  */
+      w->window_end_valid = 0;
     }
 }
 
@@ -1489,17 +1491,8 @@ if it isn't already recorded.  */)
   CHECK_BUFFER (buf);
   b = XBUFFER (buf);
 
-#if 0 /* This change broke some things.  We should make it later.  */
-  /* If we don't know the end position, return nil.
-     The user can compute it with vertical-motion if he wants to.
-     It would be nicer to do it automatically,
-     but that's so slow that it would probably bother people.  */
-  if (NILP (w->window_end_valid))
-    return Qnil;
-#endif
-
   if (! NILP (update)
-      && (windows_or_buffers_changed || NILP (w->window_end_valid))
+      && (windows_or_buffers_changed || !w->window_end_valid)
       && !noninteractive)
     {
       struct text_pos startp;
@@ -1706,7 +1699,7 @@ Return nil if window display is not up-to-date.  In that case, use
   b = XBUFFER (w->buffer);
 
   /* Fail if current matrix is not up-to-date.  */
-  if (NILP (w->window_end_valid)
+  if (!w->window_end_valid
       || current_buffer->clip_changed
       || current_buffer->prevent_redisplay_optimizations_p
       || w->last_modified < BUF_MODIFF (b)
@@ -2038,7 +2031,7 @@ replace_window (Lisp_Object old, Lisp_Object new, int setflag)
       n->pseudo_window_p = 0;
       wset_window_end_vpos (n, make_number (0));
       wset_window_end_pos (n, make_number (0));
-      wset_window_end_valid (n, Qnil);
+      n->window_end_valid = 0;
       n->frozen_window_start_p = 0;
     }
 
@@ -2973,7 +2966,7 @@ window-start value is reasonable when this function is called.  */)
           pos = *vmotion (startpos, -top, w);
 
           set_marker_both (w->start, w->buffer, pos.bufpos, pos.bytepos);
-          wset_window_end_valid (w, Qnil);
+          w->window_end_valid = 0;
           w->start_at_line_beg = (pos.bytepos == BEGV_BYTE
                                     || FETCH_BYTE (pos.bytepos - 1) == '\n');
           /* We need to do this, so that the window-scroll-functions
@@ -3189,7 +3182,7 @@ set_window_buffer (Lisp_Object window, Lisp_Object buffer, int run_hooks_p, int
   wset_window_end_pos (w, make_number (0));
   wset_window_end_vpos (w, make_number (0));
   memset (&w->last_cursor, 0, sizeof w->last_cursor);
-  wset_window_end_valid (w, Qnil);
+
   if (!(keep_margins_p && samebuf))
     { /* If we're not actually changing the buffer, don't reset hscroll and
          vscroll.  This case happens for example when called from
@@ -3958,7 +3951,7 @@ set correctly.  See the code of `split-window' for how this is done.  */)
       wset_next (o, new);
     }
 
-  wset_window_end_valid (n, Qnil);
+  n->window_end_valid = 0;
   memset (&n->last_cursor, 0, sizeof n->last_cursor);
 
   /* Get special geometry settings from reference window.  */
@@ -5368,7 +5361,7 @@ and redisplay normally--don't erase and redraw the frame.  */)
 
   /* Set the new window start.  */
   set_marker_both (w->start, w->buffer, charpos, bytepos);
-  wset_window_end_valid (w, Qnil);
+  w->window_end_valid = 0;
 
   w->optional_new_start = 1;
 
@@ -6319,7 +6312,7 @@ display marginal areas and the text area.  */)
       adjust_window_margins (w);
 
       clear_glyph_matrix (w->current_matrix);
-      wset_window_end_valid (w, Qnil);
+      w->window_end_valid = 0;
 
       ++windows_or_buffers_changed;
       adjust_glyphs (XFRAME (WINDOW_FRAME (w)));
@@ -6389,7 +6382,7 @@ Fourth parameter HORIZONTAL-TYPE is currently unused.  */)
       adjust_window_margins (w);
 
       clear_glyph_matrix (w->current_matrix);
-      wset_window_end_valid (w, Qnil);
+      w->window_end_valid = 0;
 
       ++windows_or_buffers_changed;
       adjust_glyphs (XFRAME (WINDOW_FRAME (w)));
diff --git a/src/window.h b/src/window.h
index 1ebd35a7c64..135f591ded7 100644
--- a/src/window.h
+++ b/src/window.h
@@ -175,17 +175,13 @@ struct window
        no scroll bar.  A value of t means use frame value.  */
     Lisp_Object vertical_scroll_bar_type;
 
-    /* Z - the buffer position of the last glyph in the current matrix
-       of W.  Only valid if WINDOW_END_VALID is not nil.  */
+    /* Z - the buffer position of the last glyph in the current
+       matrix of W.  Only valid if window_end_valid is nonzero.  */
     Lisp_Object window_end_pos;
+
     /* Glyph matrix row of the last glyph in the current matrix
-       of W.  Only valid if WINDOW_END_VALID is not nil.  */
+       of W.  Only valid if window_end_valid is nonzero.  */
     Lisp_Object window_end_vpos;
-    /* t if window_end_pos is truly valid.
-       This is nil if nontrivial redisplay is preempted
-       since in that case the frame image that window_end_pos
-       did not get onto the frame.  */
-    Lisp_Object window_end_valid;
 
     /* Display-table to use for displaying chars in this window.
        Nil means use the buffer's own display-table.  */
@@ -339,12 +335,17 @@ struct window
        Otherwise draw them between margin areas and text.  */
     unsigned fringes_outside_margins : 1;
 
+    /* Nonzero if window_end_pos and window_end_vpos are truly valid.
+       This is zero if nontrivial redisplay is preempted since in that case
+       the frame image that window_end_pos did not get onto the frame.  */
+    unsigned window_end_valid : 1;
+
     /* Amount by which lines of this window are scrolled in
        y-direction (smooth scrolling).  */
     int vscroll;
 
-    /* Z_BYTE - Buffer position of the last glyph in the current matrix of W.
-       Should be nonnegative, and only valid if window_end_valid is not nil.  */
+    /* Z_BYTE - buffer position of the last glyph in the current matrix of W.
+       Should be nonnegative, and only valid if window_end_valid is nonzero.  */
     ptrdiff_t window_end_bytepos;
 };
 
@@ -401,11 +402,6 @@ wset_window_end_pos (struct window *w, Lisp_Object val)
   w->window_end_pos = val;
 }
 WINDOW_INLINE void
-wset_window_end_valid (struct window *w, Lisp_Object val)
-{
-  w->window_end_valid = val;
-}
-WINDOW_INLINE void
 wset_window_end_vpos (struct window *w, Lisp_Object val)
 {
   w->window_end_vpos = val;
diff --git a/src/xdisp.c b/src/xdisp.c
index 69a8a02b2cb..d663e56acc0 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -2539,8 +2539,7 @@ check_it (struct it *it)
 static void
 check_window_end (struct window *w)
 {
-  if (!MINI_WINDOW_P (w)
-      && !NILP (w->window_end_valid))
+  if (!MINI_WINDOW_P (w) && w->window_end_valid)
     {
       struct glyph_row *row;
       eassert ((row = MATRIX_ROW (w->current_matrix,
@@ -12922,10 +12921,10 @@ static void
 reconsider_clip_changes (struct window *w, struct buffer *b)
 {
   if (b->clip_changed
-           && !NILP (w->window_end_valid)
-           && w->current_matrix->buffer == b
-           && w->current_matrix->zv == BUF_ZV (b)
-           && w->current_matrix->begv == BUF_BEGV (b))
+      && w->window_end_valid
+      && w->current_matrix->buffer == b
+      && w->current_matrix->zv == BUF_ZV (b)
+      && w->current_matrix->begv == BUF_BEGV (b))
     b->clip_changed = 0;
 
   /* If display wasn't paused, and W is not a tool bar window, see if
@@ -12933,8 +12932,7 @@ reconsider_clip_changes (struct window *w, struct buffer *b)
      we set b->clip_changed to 1 to force updating the screen.  If
      b->clip_changed has already been set to 1, we can skip this
      check.  */
-  if (!b->clip_changed
-      && BUFFERP (w->buffer) && !NILP (w->window_end_valid))
+  if (!b->clip_changed && BUFFERP (w->buffer) && w->window_end_valid)
     {
       ptrdiff_t pt;
 
@@ -13328,7 +13326,7 @@ redisplay_internal (void)
               else if (XFASTINT (w->window_end_vpos) == this_line_vpos
                        && this_line_vpos > 0)
                 wset_window_end_vpos (w, make_number (this_line_vpos - 1));
-              wset_window_end_valid (w, Qnil);
+              w->window_end_valid = 0;
 
               /* Update hint: No need to try to scroll in update_window.  */
               w->desired_matrix->no_scrolling_p = 1;
@@ -13758,7 +13756,7 @@ mark_window_display_accurate_1 (struct window *w, int accurate_p)
       else
         w->last_point = marker_position (w->pointm);
 
-      wset_window_end_valid (w, w->buffer);
+      w->window_end_valid = 1;
       w->update_mode_line = 0;
     }
 }
@@ -15460,7 +15458,7 @@ redisplay_window (Lisp_Object window, int just_this_one_p)
   set_buffer_internal_1 (XBUFFER (w->buffer));
 
   current_matrix_up_to_date_p
-    = (!NILP (w->window_end_valid)
+    = (w->window_end_valid
        && !current_buffer->clip_changed
        && !current_buffer->prevent_redisplay_optimizations_p
        && !window_outdated (w));
@@ -15483,7 +15481,7 @@ redisplay_window (Lisp_Object window, int just_this_one_p)
   specbind (Qinhibit_point_motion_hooks, Qt);
 
   buffer_unchanged_p
-    = (!NILP (w->window_end_valid)
+    = (w->window_end_valid
        && !current_buffer->clip_changed
        && !window_outdated (w));
 
@@ -15496,7 +15494,7 @@ redisplay_window (Lisp_Object window, int just_this_one_p)
       if (XMARKER (w->start)->buffer == current_buffer)
         compute_window_start_on_continuation_line (w);
 
-      wset_window_end_valid (w, Qnil);
+      w->window_end_valid = 0;
     }
 
   /* Some sanity checks.  */
@@ -15585,7 +15583,7 @@ redisplay_window (Lisp_Object window, int just_this_one_p)
 
       w->force_start = 0;
       w->vscroll = 0;
-      wset_window_end_valid (w, Qnil);
+      w->window_end_valid = 0;
 
       /* Forget any recorded base line for line number display.  */
       if (!buffer_unchanged_p)
@@ -16034,8 +16032,7 @@ redisplay_window (Lisp_Object window, int just_this_one_p)
      line.)  */
   if (w->cursor.vpos < 0)
     {
-      if (!NILP (w->window_end_valid)
-          && PT >= Z - XFASTINT (w->window_end_pos))
+      if (w->window_end_valid && PT >= Z - XFASTINT (w->window_end_pos))
         {
           clear_glyph_matrix (w->desired_matrix);
           move_it_by_lines (&it, 1);
@@ -16352,7 +16349,7 @@ try_window (Lisp_Object window, struct text_pos pos, int flags)
     }
 
   /* But that is not valid info until redisplay finishes.  */
-  wset_window_end_valid (w, Qnil);
+  w->window_end_valid = 0;
   return 1;
 }
 
@@ -16599,7 +16596,7 @@ try_window_reusing_current_matrix (struct window *w)
           wset_window_end_pos (w, make_number (Z - ZV));
           wset_window_end_vpos (w, make_number (0));
         }
-      wset_window_end_valid (w, Qnil);
+      w->window_end_valid = 0;
 
       /* Update hint: don't try scrolling again in update_window.  */
       w->desired_matrix->no_scrolling_p = 1;
@@ -16797,7 +16794,7 @@ try_window_reusing_current_matrix (struct window *w)
             (w, make_number (XFASTINT (w->window_end_vpos) - nrows_scrolled));
         }
 
-      wset_window_end_valid (w, Qnil);
+      w->window_end_valid = 0;
       w->desired_matrix->no_scrolling_p = 1;
 
 #ifdef GLYPH_DEBUG
@@ -16930,7 +16927,7 @@ find_first_unchanged_at_end_row (struct window *w,
 
   /* Display must not have been paused, otherwise the current matrix
      is not up to date.  */
-  eassert (!NILP (w->window_end_valid));
+  eassert (w->window_end_valid);
 
   /* A value of window_end_pos >= END_UNCHANGED means that the window
      end is in the range of changed text.  If so, there is no
@@ -17114,7 +17111,7 @@ row_containing_pos (struct window *w, ptrdiff_t charpos,
 
 /* Try to redisplay window W by reusing its existing display.  W's
    current matrix must be up to date when this function is called,
-   i.e. window_end_valid must not be nil.
+   i.e. window_end_valid must be nonzero.
 
    Value is
 
@@ -17222,7 +17219,7 @@ try_window_id (struct window *w)
     GIVE_UP (7);
 
   /* Verify that display wasn't paused.  */
-  if (NILP (w->window_end_valid))
+  if (!w->window_end_valid)
     GIVE_UP (8);
 
   /* Can't use this if highlighting a region because a cursor movement
@@ -17873,7 +17870,7 @@ try_window_id (struct window *w)
             debug_end_vpos = XFASTINT (w->window_end_vpos));
 
   /* Record that display has not been completed.  */
-  wset_window_end_valid (w, Qnil);
+  w->window_end_valid = 0;
   w->desired_matrix->no_scrolling_p = 1;
   return 3;
 
@@ -27782,7 +27779,7 @@ note_mouse_highlight (struct frame *f, int x, int y)
      And verify the buffer's text has not changed.  */
   b = XBUFFER (w->buffer);
   if (part == ON_TEXT
-      && EQ (w->window_end_valid, w->buffer)
+      && w->window_end_valid
       && w->last_modified == BUF_MODIFF (b)
       && w->last_overlay_modified == BUF_OVERLAY_MODIFF (b))
     {