Avoid looping over all frame windows to freeze and unfreeze.

* window.h (struct window): Drop frozen_window_start_p.
(freeze_window_starts): Drop prototype.
* frame.h (struct frame): New frozen_window_starts flag.
(FRAME_WINDOWS_FROZEN): New macro.
* window.c (freeze_window_start, freeze_window_starts):
Remove.
(select_window, replace_window): Adjust users.
* xdisp.c (resize_mini_window): Use FRAME_WINDOWS_FROZEN.
(window_frozen_p): New function.
(redisplay_window): Use it.

5 files changed, 58 insertions, 48 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 759f66bc1b4..679b82ba63c 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,17 @@
+2013-08-12  Dmitry Antipov  <dmantipov@yandex.ru>
+
+        Avoid looping over all frame windows to freeze and unfreeze.
+        * window.h (struct window): Drop frozen_window_start_p.
+        (freeze_window_starts): Drop prototype.
+        * frame.h (struct frame): New frozen_window_starts flag.
+        (FRAME_WINDOWS_FROZEN): New macro.
+        * window.c (freeze_window_start, freeze_window_starts):
+        Remove.
+        (select_window, replace_window): Adjust users.
+        * xdisp.c (resize_mini_window): Use FRAME_WINDOWS_FROZEN.
+        (window_frozen_p): New function.
+        (redisplay_window): Use it.
+
 2013-08-12  Paul Eggert  <eggert@cs.ucla.edu>
 
         Fix some fd issues when running subprocesses (Bug#15035).
diff --git a/src/frame.h b/src/frame.h
index 33e4bb71d7a..e44003b15ca 100644
--- a/src/frame.h
+++ b/src/frame.h
@@ -410,6 +410,10 @@ struct frame
   /* Nonzero means that the pointer is invisible. */
   unsigned pointer_invisible :1;
 
+  /* Nonzero means that all windows except mini-window and
+     selected window on this frame have frozen window starts.  */
+  unsigned frozen_window_starts : 1;
+
   /* Nonzero if we should actually display the scroll bars on this frame.  */
   enum vertical_scroll_bar_type vertical_scroll_bar_type;
 
@@ -761,6 +765,10 @@ default_pixels_per_inch_y (void)
 /* Not really implemented.  */
 #define FRAME_WANTS_MODELINE_P(f) (f)->wants_modeline
 
+/* Nonzero if all windows except selected window and mini window
+   are frozen on frame F.  */
+#define FRAME_WINDOWS_FROZEN(f) (f)->frozen_window_starts
+
 /* Nonzero if a size change has been requested for frame F
    but not yet really put into effect.  This can be true temporarily
    when an X event comes in at a bad time.  */
diff --git a/src/window.c b/src/window.c
index 31b5b2717a4..47a7b58ba9b 100644
--- a/src/window.c
+++ b/src/window.c
@@ -69,7 +69,6 @@ static int get_leaf_windows (struct window *, struct window **, int);
 static void window_scroll (Lisp_Object, EMACS_INT, bool, int);
 static void window_scroll_pixel_based (Lisp_Object, int, bool, int);
 static void window_scroll_line_based (Lisp_Object, int, bool, int);
-static int freeze_window_start (struct window *, void *);
 static Lisp_Object window_list (void);
 static int add_window_to_list (struct window *, void *);
 static Lisp_Object next_window (Lisp_Object, Lisp_Object,
@@ -499,7 +498,6 @@ select_window (Lisp_Object window, Lisp_Object norecord, int inhibit_point_swap)
   CHECK_LIVE_WINDOW (window);
 
   w = XWINDOW (window);
-  w->frozen_window_start_p = 0;
 
   /* Make the selected window's buffer current.  */
   Fset_buffer (w->contents);
@@ -2055,7 +2053,6 @@ replace_window (Lisp_Object old, Lisp_Object new, int setflag)
       wset_window_end_vpos (n, make_number (0));
       wset_window_end_pos (n, make_number (0));
       n->window_end_valid = 0;
-      n->frozen_window_start_p = 0;
     }
 
   tem = o->next;
@@ -6453,38 +6450,6 @@ foreach_window_1 (struct window *w, int (*fn) (struct window *, void *), void *u
   return cont;
 }
 
-
-/* Freeze or unfreeze the window start of W unless it is a
-   mini-window or the selected window.  FREEZE_P non-null means freeze
-   the window start.  */
-
-static int
-freeze_window_start (struct window *w, void *freeze_p)
-{
-  if (MINI_WINDOW_P (w)
-      || (WINDOWP (selected_window) /* Can be nil in corner cases.  */
-         && (w == XWINDOW (selected_window)
-             || (MINI_WINDOW_P (XWINDOW (selected_window))
-                 && ! NILP (Vminibuf_scroll_window)
-                 && w == XWINDOW (Vminibuf_scroll_window)))))
-    freeze_p = NULL;
-
-  w->frozen_window_start_p = freeze_p != NULL;
-  return 1;
-}
-
-
-/* Freeze or unfreeze the window starts of all leaf windows on frame
-   F, except the selected window and a mini-window.  FREEZE_P non-zero
-   means freeze the window start.  */
-
-void
-freeze_window_starts (struct frame *f, bool freeze_p)
-{
-  foreach_window (f, freeze_window_start, freeze_p ? f : 0);
-}
-
-
 /***********************************************************************
                             Initialization
  ***********************************************************************/
diff --git a/src/window.h b/src/window.h
index 24949e1e287..260a672d93a 100644
--- a/src/window.h
+++ b/src/window.h
@@ -316,11 +316,6 @@ struct window
        Currently only used for menu bar windows of frames.  */
     unsigned pseudo_window_p : 1;
 
-    /* 1 means the window start of this window is frozen and may not
-       be changed during redisplay.  If point is not in the window,
-       accept that.  */
-    unsigned frozen_window_start_p : 1;
-
     /* Non-zero means fringes are drawn outside display margins.
        Otherwise draw them between margin areas and text.  */
     unsigned fringes_outside_margins : 1;
@@ -888,7 +883,6 @@ extern Lisp_Object window_from_coordinates (struct frame *, int, int,
 extern void resize_frame_windows (struct frame *, int, bool);
 extern void restore_window_configuration (Lisp_Object);
 extern void delete_all_child_windows (Lisp_Object);
-extern void freeze_window_starts (struct frame *, bool);
 extern void grow_mini_window (struct window *, int);
 extern void shrink_mini_window (struct window *);
 extern int window_relative_x_coord (struct window *, enum window_part, int);
diff --git a/src/xdisp.c b/src/xdisp.c
index 67f4720e170..37f2c94b5f8 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -10460,7 +10460,8 @@ resize_mini_window (struct window *w, int exact_p)
           if (height > WINDOW_TOTAL_LINES (w))
             {
               int old_height = WINDOW_TOTAL_LINES (w);
-              freeze_window_starts (f, 1);
+
+              FRAME_WINDOWS_FROZEN (f) = 1;
               grow_mini_window (w, height - WINDOW_TOTAL_LINES (w));
               window_height_changed_p = WINDOW_TOTAL_LINES (w) != old_height;
             }
@@ -10468,7 +10469,8 @@ resize_mini_window (struct window *w, int exact_p)
                    && (exact_p || BEGV == ZV))
             {
               int old_height = WINDOW_TOTAL_LINES (w);
-              freeze_window_starts (f, 0);
+
+              FRAME_WINDOWS_FROZEN (f) = 0;
               shrink_mini_window (w);
               window_height_changed_p = WINDOW_TOTAL_LINES (w) != old_height;
             }
@@ -10479,19 +10481,21 @@ resize_mini_window (struct window *w, int exact_p)
           if (height > WINDOW_TOTAL_LINES (w))
             {
               int old_height = WINDOW_TOTAL_LINES (w);
-              freeze_window_starts (f, 1);
+
+              FRAME_WINDOWS_FROZEN (f) = 1;
               grow_mini_window (w, height - WINDOW_TOTAL_LINES (w));
               window_height_changed_p = WINDOW_TOTAL_LINES (w) != old_height;
             }
           else if (height < WINDOW_TOTAL_LINES (w))
             {
               int old_height = WINDOW_TOTAL_LINES (w);
-              freeze_window_starts (f, 0);
+
+              FRAME_WINDOWS_FROZEN (f) = 0;
               shrink_mini_window (w);
 
               if (height)
                 {
-                  freeze_window_starts (f, 1);
+                  FRAME_WINDOWS_FROZEN (f) = 1;
                   grow_mini_window (w, height - WINDOW_TOTAL_LINES (w));
                 }
 
@@ -10874,6 +10878,31 @@ mode_line_update_needed (struct window *w)
           && (w->column_number_displayed != current_column ()));
 }
 
+/* Nonzero if window start of W is frozen and may not be changed during
+   redisplay.  */
+
+static bool
+window_frozen_p (struct window *w)
+{
+  if (FRAME_WINDOWS_FROZEN (XFRAME (WINDOW_FRAME (w))))
+    {
+      Lisp_Object window;
+
+      XSETWINDOW (window, w);
+      if (MINI_WINDOW_P (w))
+        return 0;
+      else if (EQ (window, selected_window))
+        return 0;
+      else if (MINI_WINDOW_P (XWINDOW (selected_window))
+               && EQ (window, Vminibuf_scroll_window))
+        /* This special window can't be frozen too.  */
+        return 0;
+      else
+        return 1;
+    }
+  return 0;
+}
+
 /***********************************************************************
                      Mode Lines and Frame Titles
  ***********************************************************************/
@@ -15510,7 +15539,7 @@ redisplay_window (Lisp_Object window, int just_this_one_p)
 
   /* Handle case where place to start displaying has been specified,
      unless the specified location is outside the accessible range.  */
-  if (w->force_start || w->frozen_window_start_p)
+  if (w->force_start || window_frozen_p (w))
     {
       /* We set this later on if we have to adjust point.  */
       int new_vpos = -1;
@@ -15555,7 +15584,7 @@ redisplay_window (Lisp_Object window, int just_this_one_p)
           goto need_larger_matrices;
         }
 
-      if (w->cursor.vpos < 0 && !w->frozen_window_start_p)
+      if (w->cursor.vpos < 0 && !window_frozen_p (w))
         {
           /* If point does not appear, try to move point so it does
              appear. The desired matrix has been built above, so we