Make scrollbar structures into lisp objects, so that they can be

	GC'd; this allows windows and scrollbars can refer to each other
	without worrying about dangling pointers.
	* xterm.h (struct x_display): vertical_scrollbars and
	judge_timestamp members deleted.
	(struct scrollbar): Redesigned to be a template for a Lisp_Vector.
	(SCROLLBAR_VEC_SIZE, XSCROLLBAR, SCROLLBAR_PACK, SCROLLBAR_UNPACK,
	SCROLLBAR_X_WINDOW, SET_SCROLLBAR_X_WINDOW,
	VERTICAL_SCROLLBAR_INSIDE_WIDTH, VERTICAL_SCROLLBAR_TOP_RANGE,
	VERTICAL_SCROLLBAR_INSIDE_HEIGHT, VERTICAL_SCROLLBAR_MIN_HANDLE):
	New macros, to help deal with the lispy structures, and deal with
	the graphics.
	* frame.h (WINDOW_VERTICAL_SCROLLBAR): Macro deleted.
	(struct frame): New fields `scrollbars' and
	`condemned_scrollbars', for use by the scrollbar implementation.
	[MULTI_FRAME and not MULTI_FRAME] (FRAME_SCROLLBARS,
	FRAME_CONDEMNED_SCROLLBARS): Accessors for the new field.
	* window.h (struct window): Doc fix for vertical_scrollbar field.
	* frame.c (make_frame): Initialize the `scrollbars' and
	`condemned_scrollbars' fields of the new frame.
	* alloc.c (mark_object): Mark the `scrollbars' and
	`condemned_scrollbars' slots of frames.
	* xterm.c (x_window_to_scrollbar): Scrollbars are chained on
	frames' scrollbar field, not their x.display->vertical_scrollbars
	field.
	(x_scrollbar_create, x_scrollbar_set_handle, x_scrollbar_move,
	x_scrollbar_remove, XTset_vertical_scrollbar,
	XTcondemn_scrollbars, XTredeem_scrollbar, XTjudge_scrollbars,
	x_scrollbar_expose, x_scrollbar_handle_click,
	x_scrollbar_handle_motion): Substantially rewritten to correct
	typos and brainos, and to accomodate the lispy structures.

3 files changed, 13 insertions, 9 deletions

diff --git a/src/alloc.c b/src/alloc.c
index 9fecc60d09f..f49dbdf9e81 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -1,11 +1,11 @@
 /* Storage allocation and gc for GNU Emacs Lisp interpreter.
-   Copyright (C) 1985, 1986, 1988, 1992 Free Software Foundation, Inc.
+   Copyright (C) 1985, 1986, 1988, 1992, 1993 Free Software Foundation, Inc.
 
 This file is part of GNU Emacs.
 
 GNU Emacs is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
-the Free Software Foundation; either version 1, or (at your option)
+the Free Software Foundation; either version 2, or (at your option)
 any later version.
 
 GNU Emacs is distributed in the hope that it will be useful,
@@ -1497,6 +1497,8 @@ mark_object (objptr)
         mark_object (&ptr->selected_window);
         mark_object (&ptr->minibuffer_window);
         mark_object (&ptr->param_alist);
+        mark_object (&ptr->scrollbars);
+        mark_object (&ptr->condemned_scrollbars);
       }
       break;
 #endif /* not MULTI_FRAME */
diff --git a/src/frame.c b/src/frame.c
index 7ac1682830a..e393e597e0a 100644
--- a/src/frame.c
+++ b/src/frame.c
@@ -1,5 +1,5 @@
 /* Generic frame functions.
-   Copyright (C) 1989, 1992 Free Software Foundation.
+   Copyright (C) 1989, 1992, 1993 Free Software Foundation.
 
 This file is part of GNU Emacs.
 
@@ -160,8 +160,9 @@ make_frame (mini_p)
   f->explicit_name = 0;
   f->can_have_scrollbars = 0;
   f->has_vertical_scrollbars = 0;
-
   f->param_alist = Qnil;
+  f->scrollbars = Qnil;
+  f->condemned_scrollbars = Qnil;
 
   root_window = make_window ();
   if (mini_p)
diff --git a/src/window.h b/src/window.h
index b05386d978d..51a27157d59 100644
--- a/src/window.h
+++ b/src/window.h
@@ -1,5 +1,5 @@
 /* Window definitions for GNU Emacs.
-   Copyright (C) 1985, 1986, 1992 Free Software Foundation, Inc.
+   Copyright (C) 1985, 1986, 1992, 1993 Free Software Foundation, Inc.
 
 This file is part of GNU Emacs.
 
@@ -123,10 +123,11 @@ struct window
     Lisp_Object last_modified;
     /* Value of point at that time */
     Lisp_Object last_point;
-    /* Pointer to this window's vertical scrollbar, tagged as an
-       integer.  If this window is newly created and we haven't
-       displayed a scrollbar in it yet, or if the frame doesn't have
-       any scrollbars, this is nil.  */
+    /* This window's vertical scrollbar.  This field is only for use
+       by the window-system-dependent code which implements the
+       scrollbars; it can store anything it likes here.  If this
+       window is newly created and we haven't displayed a scrollbar in
+       it yet, or if the frame doesn't have any scrollbars, this is nil.  */
     Lisp_Object vertical_scrollbar;
 
 /* The rest are currently not used or only half used */