[xemacs-hg @ 2001-06-18 07:09:50 by ben] --------------------------------------------------------------- DOCUMENTATION FIXES: --------------------------------------------------------------- eval.c: Correct documentation. elhash.c: Doc correction. --------------------------------------------------------------- LISP OBJECT CLEANUP: --------------------------------------------------------------- bytecode.h, buffer.h, casetab.h, chartab.h, console-msw.h, console.h, database.c, device.h, eldap.h, elhash.h, events.h, extents.h, faces.h, file-coding.h, frame.h, glyphs.h, gui-x.h, gui.h, keymap.h, lisp-disunion.h, lisp-union.h, lisp.h, lrecord.h, lstream.h, mule-charset.h, objects.h, opaque.h, postgresql.h, process.h, rangetab.h, specifier.h, toolbar.h, tooltalk.h, ui-gtk.h: Add wrap_* to all objects (it was already there for a few of them) -- an expression to encapsulate a pointer into a Lisp object, rather than the inconvenient XSET*. "wrap" was chosen because "make" as in make_int(), make_char() is not appropriate. (It implies allocation. The issue does not exist for ints and chars because they are not allocated.) Full error checking has been added to these expressions. When used without error checking, non-union build, use of these expressions will incur no loss of efficiency. (In fact, XSET* is now defined in terms of wrap_* in a non-union build.) In a union build, you will also get no loss of efficiency provided that you have a decent optimizing compiler, and a compiler that either understands inlines or automatically inlines those particular functions. (And since people don't normally do their production builds on union, it doesn't matter.) Update the sample Lisp object definition in lrecord.h accordingly. dumper.c: Fix places in dumper that referenced wrap_object to reference its new name, wrap_pointer_1. buffer.c, bufslots.h, conslots.h, console.c, console.h, devslots.h, device.c, device.h, frame.c, frame.h, frameslots.h, window.c, window.h, winslots.h: -- Extract out the Lisp objects of `struct device' into devslots.h, just like for the other structures. -- Extract out the remaining (not copied into the window config) Lisp objects in `struct window' into winslots.h; use different macros (WINDOW_SLOT vs. WINDOW_SAVED_SLOT) to differentiate them. -- Eliminate the `dead' flag of `struct frame', since it duplicates information already available in `framemeths', and fix FRAME_LIVE_P accordingly. (Devices and consoles already work this way.) -- In *slots.h, switch to system where MARKED_SLOT is automatically undef'd at the end of the file. (Follows what winslots.h already does.) -- Update the comments at the beginning of *slots.h to be accurate. -- When making any of the above objects dead, zero it out entirely and reset all Lisp object slots to Qnil. (We were already doing this somewhat, but not consistently.) This (1) Eliminates the possibility of extra objects hanging around that ought to be GC'd, (2) Causes an immediate crash if anyone tries to access a structure in one of these objects, (3) Ensures consistent behavior wrt dead objects. dialog-msw.c: Use internal_object_printer, since this object should not escape. --------------------------------------------------------------- FIXING A CRASH THAT I HIT ONCE (AND A RELATED BAD BEHAVIOR): --------------------------------------------------------------- eval.c: Fix up some comments about the FSF implementation. Fix two nasty bugs: (1) condition_case_unwind frees the conses sitting in the catch->tag slot too quickly, resulting in a crash that I hit. (2) catches need to be unwound one at a time when calling unwind-protect code, rather than all at once at the end; otherwise, incorrect behavior can result. (A comment shows exactly how.) backtrace.h: Improve comment about FSF differences in the handler stack. --------------------------------------------------------------- FIXING A CRASH THAT I REPEATEDLY HIT WHEN USING THE MOUSE WHEEL UNDER MSWINDOWS: --------------------------------------------------------------- Basic idea: My crash is due either to a dead, non-marked, GC-collected frame inside of a window mirror, or a prematurely freed window mirror. We need to mark the Lisp objects inside of window mirrors. Tracking the lifespan of window mirrors and scrollbar instances is extremely hard, and there may well be lurking bugs where such objects are freed too soon. The only safe way to fix these problems (and it fixes both problems at once) is to make both of these structures Lisp objects. lrecord.h, emacs.c, inline.c, scrollbar-gtk.c, scrollbar-msw.c, scrollbar-x.c, scrollbar.c, scrollbar.h, symsinit.h: Make scrollbar instances actual Lisp objects. Mark the window mirrors in them. inline.c needs to know about scrollbar.h now. Record the new type in lrecord.h. Fix up scrollbar-*.c appropriately. Create a hash table in scrollbar-msw.c so that the scrollbar instances stored in scrollbar HWND's are properly GC-protected. Create complex_vars_of_scrollbar_mswindows() to create the hash table at startup, and call it from emacs.c. Don't store the scrollbar instance as a property of the GTK scrollbar, as it's not used and if we did this, we'd have to separately GC-protect it in a hash table, like in MS Windows. lrecord.h, frame.h, frame.c, frameslots.h, redisplay.c, window.c, window.h: Move mark_window_mirror from redisplay.c to window.c. Make window mirrors actual Lisp objects. Tell lrecord.h about them. Change the window mirror member of struct frame from a pointer to a Lisp object, and add XWINDOW_MIRROR in appropriate places. Mark the scrollbar instances in the window mirror. redisplay.c, redisplay.h, alloc.c: Delete mark_redisplay. Don't call mark_redisplay. We now mark frame-specific structures in mark_frame. NOTE: I also deleted an extremely questionable call to update_frame_window_mirrors(). It was extremely questionable before, and now totally impossible, since it will create Lisp objects during redisplay. frame.c: Mark the scrollbar instances, which are now Lisp objects. Call mark_gutter() here, not in mark_redisplay(). gutter.c: Update comments about correct marking. --------------------------------------------------------------- ISSUES BROUGHT UP BY MARTIN: --------------------------------------------------------------- buffer.h: Put back these macros the way Steve T and I think they ought to be. I already explained in a previous changelog entry why I think these macros should be the way I'd defined them. Once again: We fix these macros so they don't care about the type of their lvalues. The non-C-string equivalents of these already function in the same way, and it's correct because it should be OK to pass in a CBufbyte *, a BufByte *, a Char_Binary *, an UChar_Binary *, etc. The whole reason for these different types is to work around errors caused by signed-vs-unsigned non-matching types. Any possible error that might be caught in a DFC macro would also be caught wherever the argument is used elsewhere. So creating multiple macro versions would add no useful error-checking and just further complicate an already complicated area. As for Martin's "ANSI aliasing" bug, XEmacs is not ANSI-aliasing clean and probably never will be. Unless the board agrees to change XEmacs in this way (and we really don't want to go down that road), this is not a bug. sound.h: Undo Martin's type change. signal.c: Fix problem identified by Martin with Linux and g++ due to non-standard declaration of setitimer(). systime.h: Update the docs for "qxe_" to point out why making the encapsulation explicit is always the right way to go. (setitimer() itself serves as an example.) For 21.4: update-elc-2.el: Correct misplaced parentheses, making lisp/mule not get recompiled.

;;; compat.el --- Mechanism for non-intrusively providing compatibility funs.

;; Copyright (C) 2000 Ben Wing.

;; Author: Ben Wing <ben@xemacs.org>
;; Maintainer: Ben Wing
;; Keywords: internal

;; This file is part of XEmacs.

;; XEmacs 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 2, or (at your option)
;; any later version.

;; XEmacs is distributed in the hope that it will be useful, but
;; WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
;; General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with XEmacs; see the file COPYING.  If not, write to the 
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.

;;; Synched up with: Not in FSF.

;;; Authorship:

; Written May 2000 by Ben Wing.

;;; Commentary:

;; Typical usage:

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; 1. Wrap modules that define compatibility functions like this:     ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

;(compat-define-group 'fsf-compat)

;(compat-define-functions 'fsf-compat

;(defun overlayp (object)
;  "Return t if OBJECT is an overlay."
;  (and (extentp object)
;       (extent-property object 'overlay)))

;(defun make-overlay (beg end &optional buffer front-advance rear-advance)
;  ...)

;...

;) ;; end of (compat-define-group 'fsf-compat)

;;;; overlay.el ends here


;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; 2. Wrap modules that use the compatibility functions like this:    ;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

;(compat 'fsf-compat

;(defun random-module-my-fun (bar baz)
;  (if (fboundp 'overlays-in) (overlays-in bar baz)))

;...

;) ;; end of (compat 'fsf-compat)

;;;; random-module.el ends here


(defun compat-hash-table (group)
  (get group 'compat-table))

(defun compat-make-hash-table (group)
  (put group 'compat-table (make-hash-table)))

(defmacro compat-define-group (group)
  "Define GROUP as a group of compatibility functions.
Individual functions are defined using `compat-define-functions'.
Once defined, the functions can be used by wrapping your code in the
`compat' macro.

If GROUP is already defined, nothing happens."
  (let ((group (eval group)))
    (or (hash-table-p (compat-hash-table group))
	(compat-make-hash-table group))))

(defmacro compat-clear-functions (group)
  "Clear all defined functions and macros out of GROUP."
  (let ((group (eval group)))
    (clrhash (compat-hash-table group))))

(defmacro compat-define-functions (group &rest body)
  "Define compatibility functions in GROUP.
You should simply wrap this around the code that defines the functions.
Any functions and macros defined at top level using `defun' or `defmacro'
will be noticed and added to GROUP.  Other top-level code will be executed
normally.  All code and definitions in this group can safely reference any
other functions in this group -- the code is effectively wrapped in a
`compat' call.  You can call `compat-define-functions' more than once, if
necessary, for a single group.

What actually happens is that the functions and macros defined here are in
fact defined using names prefixed with GROUP.  To use these functions,
wrap any calling code with the `compat' macro, which lexically renames
the function and macro calls appropriately."
  (let ((group (eval group)))
    (let (fundef
	  (body-tail body))
      (while body-tail
	(setq fundef (car body-tail))
	(when (and (consp fundef) (eq (car fundef) 'defun))
	  (puthash (second fundef) (third fundef) (compat-hash-table group)))
	(when (and (consp fundef) (eq (car fundef) 'defmacro))
	  (puthash (second fundef) (third fundef) (compat-hash-table group)))
	(setq body-tail (cdr body-tail))))
    (let (fundef
	  (body-tail body)
	  result)
      (while body-tail
	(setq fundef (car body-tail))
	(push
	 (cond ((and (consp fundef) (eq (car fundef) 'defun))
		(nconc (list 'defun
			      (intern (concat (symbol-name group) "-"
					      (symbol-name (second fundef))))
			      (third fundef))
			(nthcdr 3 fundef)))
	       ((and (consp fundef) (eq (car fundef) 'defmacro))
		(nconc (list 'defmacro
			      (intern (concat (symbol-name group) "-"
					      (symbol-name (second fundef))))
			      (third fundef))
			(nthcdr 3 fundef)))
	       (t fundef))
	 result)
	(setq body-tail (cdr body-tail)))
      (nconc (list 'compat (list 'quote group)) (nreverse result)))))

(defvar compat-active-groups nil)

(defun compat-fboundp (groups fun)
  "T if FUN is either `fboundp' or one of the compatibility funs in GROUPS.
GROUPS is a list of compatibility groups as defined using
`compat-define-group'."
  (or (fboundp fun)
      (block nil
	(mapcar #'(lambda (group)
		    (if (gethash fun (compat-hash-table group))
			(return t)))
		groups))))

(defmacro compat (group &rest body)
  "Make use of compatibility functions and macros in GROUP.
You should simply wrap this around the code that uses the functions
and macros in GROUP.  Typically, a call to `compat' should be placed
at the top of an ELisp module, with the closing parenthesis at the
bottom; use this in place of a `require' statement.  Wrapped code can
be either function or macro definitions or other ELisp code, and
wrapped function or macro definitions need not be at top level.  All
calls to the compatibility functions or macros will be noticed anywhere
within the wrapped code.  Calls to `fboundp' within the wrapped code
will also behave correctly when called on compatibility functions and
macros, even though they would return nil elsewhere (including in code
in other modules called dynamically from the wrapped code).

The functions and macros define in GROUP are actually defined under
prefixed names, to avoid namespace clashes and bad interactions with
other code that calls `fboundp'.  All calls inside of the wrapped code
to the compatibility functions and macros in GROUP are lexically
mapped to the prefixed names.  Since this is a lexical mapping, code
in other modules that is called by functions in this module will not
be affected."
  (let ((group (eval group))
	defs)
    (maphash
     #'(lambda (fun args)
	 (push
	  (list fun args
		(nconc
		 (list 'list
		       (list 'quote 
			     (intern (concat (symbol-name group) "-"
					     (symbol-name fun)))))
		 args))
	  defs))
     (compat-hash-table group))
    ;; it would be cleaner to use `lexical-let' instead of `let', but that
    ;; causes function definitions to have obnoxious, unreadable junk in
    ;; them.  #### Move `lexical-let' into C!!!
    `(let ((compat-active-groups (cons ',group compat-active-groups)))
       (macrolet ((fboundp (fun) `(compat-fboundp ',compat-active-groups ,fun))
		  ,@defs)
	 ,@body))))