Run window change functions during redisplay

* doc/lispref/windows.texi (Window Sizes): Move (and rename)
descriptions of 'window-pixel-height-before-size-change' and
'window-pixel-width-before-size-change' to Window Hooks
section.
(Window Configurations): Remove warning against use of
'save-window-excursion' in 'window-size-change-functions'.
(Window Hooks): Rewrite section according to redesign of
window change functions.
* lisp/erc/erc-track.el (erc-window-configuration-change)
(erc-modified-channels-update): Call latter directly from
'window-configuration-change-hook' instead via
'post-command-hook'.
* lisp/frame.el (frame-size-changed-p): Change nomenclature
in let bindings.
* lisp/net/rcirc.el (rcirc-window-configuration-change)
(rcirc-window-configuration-change-1): Call latter directly
from 'window-configuration-change-hook' instead via
'post-command-hook'.
* lisp/window.el (window-pixel-width-before-size-change)
(window-pixel-height-before-size-change): Defalias.
(window--resize-mini-window, window-resize)
(adjust-window-trailing-edge, delete-window)
(delete-other-windows, balance-windows): Don't run
'window-configuration-change-hook' any more from here.
(split-window): Don't run 'window-configuration-change-hook'
from here.  'run-window-scroll-functions' from here.
(window--adjust-process-windows): Run from
'window-configuration-change-hook' only.
* src/frame.c (old_selected_frame): New Lisp variable.
(make_frame): Initialize frame's change_stamp slot.
(Fold_selected_frame): New function.
* src/frame.h (struct frame): New slots old_selected_window,
window_change, change_stamp and number_of_windows.
(fset_old_selected_window): New inlined function.
(FRAME_WINDOW_CHANGE, FRAME_OLD_SELECTED_WINDOW): New macros.
* src/window.c (old_selected_window): New Lisp variable.
(wset_old_buffer): New inlined function.
(Fframe_old_selected_window, Fold_selected_window)
(Fwindow_old_buffer): New functions.
(Fwindow_old_pixel_width, Fwindow_old_pixel_height): Rename
from Fwindow_pixel_width_before_size_change and
Fwindow_pixel_height_before_size_change.  Update doc-strings.
(Fwindow_old_body_pixel_width, Fwindow_old_body_pixel_height):
New functions.
(Fdelete_other_windows_internal): Set frame's window_change
slot instead of running 'window-configuration-change-hook'.
(Frun_window_configuration_change_hook): In doc-string tell
that this function is no more needed.
(Frun_window_scroll_functions): Amend doc-string.  Run with
window's buffer current.
(window_sub_list, window_change_record_windows)
(window_change_record_frame, window_change_record)
(run_window_change_functions_1, run_window_change_functions):
New functions.
(set_window_buffer): Set frame's window_change slot instead of
running 'window-configuration-change-hook'.
(make_window): Don't initialize pixel_width_before_size_change
and pixel_height_before_size_change slots.
(window_resize_apply, Fdelete_window_internal): Set frame's
window_change slot.
(Fsplit_window_internal): Set frame's window_change slot.
Don't run 'window-scroll-functions' from here.
* src/window.h (struct window): New slots old_buffer,
change_stamp, old_pixel_width (renamed from
pixel_width_before_size_change), old_pixel_height (renamed
from pixel_height_before_size_change), old_body_pixel_width
and old_body_pixel_height.
* src/xdisp.c (init_iterator): Set frame's window_change slot
when the body height or width changes.
(prepare_menu_bars): Don't run_window_size_change_functions.
(redisplay_internal): Don't run_window_size_change_functions,
run_window_change_functions instead.

1 files changed, 22 insertions, 5 deletions

diff --git a/src/window.h b/src/window.h
index ee6ec3bb19a..9c4aea85ea6 100644
--- a/src/window.h
+++ b/src/window.h
@@ -142,6 +142,11 @@ struct window
        as well.  */
     Lisp_Object contents;
 
+    /* The old buffer of this window, set to this window's buffer by
+       run_window_change_functions every time it sees this window.
+       Unused for internal windows.  */
+    Lisp_Object old_buffer;
+
     /* A marker pointing to where in the text to start displaying.
        BIDI Note: This is the _logical-order_ start, i.e. the smallest
        buffer position visible in the window, not necessarily the
@@ -229,6 +234,14 @@ struct window
     /* Unique number of window assigned when it was created.  */
     EMACS_INT sequence_number;
 
+    /* The change stamp of this window.  Set to 0 when the window is
+       created, it is set to its frame's change stamp every time
+       run_window_change_functions is run on that frame with this
+       window live.  It is left alone when the window exists only
+       within a window configuration.  Not useful for internal
+       windows.  */
+    int change_stamp;
+
     /* The upper left corner pixel coordinates of this window, as
        integers relative to upper left corner of frame = 0, 0.  */
     int pixel_left;
@@ -243,10 +256,13 @@ struct window
     int pixel_width;
     int pixel_height;
 
-    /* The pixel sizes of the window at the last time
-       `window-size-change-functions' was run.  */
-    int pixel_width_before_size_change;
-    int pixel_height_before_size_change;
+    /* The pixel and pixel body sizes of the window at the last time
+       run_window_change_functions was run with this window live.  Not
+       useful for internal windows.  */
+    int old_pixel_width;
+    int old_pixel_height;
+    int old_body_pixel_width;
+    int old_body_pixel_height;
 
     /* The size of the window.  */
     int total_cols;
@@ -1023,6 +1039,7 @@ wset_next_buffers (struct window *w, Lisp_Object val)
    This value is always the same as FRAME_SELECTED_WINDOW (selected_frame).  */
 
 extern Lisp_Object selected_window;
+extern Lisp_Object old_selected_window;
 
 /* This is a time stamp for window selection, so we can find the least
    recently used window.  Its only users are Fselect_window,
@@ -1051,7 +1068,7 @@ extern void grow_mini_window (struct window *, int, bool);
 extern void shrink_mini_window (struct window *, bool);
 extern int window_relative_x_coord (struct window *, enum window_part, int);
 
-void run_window_size_change_functions (Lisp_Object);
+void run_window_change_functions (void);
 
 /* Make WINDOW display BUFFER.  RUN_HOOKS_P means it's allowed
    to run hooks.  See make_frame for a case where it's not allowed.  */