;;; w3m-xmas.el --- The stuffs to use emacs-w3m on XEmacs

;; Copyright (C) 2001, 2002, 2003, 2004, 2005
;; TSUCHIYA Masatoshi <tsuchiya@namazu.org>

;; Authors: Yuuichi Teranishi  <teranisi@gohome.org>,
;;          TSUCHIYA Masatoshi <tsuchiya@namazu.org>,
;;          Katsumi Yamaoka    <yamaoka@jpl.org>
;; Keywords: w3m, WWW, hypermedia

;; This file is a part of emacs-w3m.

;; This program 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.

;; This program 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 this program; if not, you can either send email to this
;; program's maintainer or write to: The Free Software Foundation,
;; Inc.; 59 Temple Place, Suite 330; Boston, MA 02111-1307, USA.


;;; Commentary:

;; This file contains the stuffs to use emacs-w3m on XEmacs.  For more
;; detail about emacs-w3m, see:
;;
;;    http://emacs-w3m.namazu.org/


;;; Code:

;; Fix an XEmacs 21.5 bug in `call-process-region'.  It has been reported
;; as <URL:http://news.gmane.org/group/gmane.emacs.xemacs.beta/thread=16564>.
(when (and (executable-find "cat")
	   (with-temp-buffer
	     (insert "bar")
	     (backward-char)
	     (call-process-region (1- (point)) (point) "cat" t t)
	     (goto-char (point-min))
	     (not (looking-at "bar"))))
  (defadvice call-process-region (around fix-xemacs-bug activate)
    "Narrow to the specified region while running the original function.
It fixes an XEmacs 21.5 bug.  Advised by emacs-w3m."
    (save-restriction
      (narrow-to-region (ad-get-arg 0) (ad-get-arg 1))
      (goto-char (point-max))
      ad-do-it)))

(require 'w3m-util)
(require 'w3m-proc)
(require 'w3m-image)
(require 'w3m-favicon)
(eval-and-compile
  (when (featurep 'mule)
    (require 'w3m-ccl)))

;; Functions and variables which should be defined in the other module
;; at run-time.
(eval-when-compile
  (defvar w3m-coding-system)
  (defvar w3m-current-title)
  (defvar w3m-current-url)
  (defvar w3m-default-coding-system)
  (defvar w3m-display-inline-images)
  (defvar w3m-icon-directory)
  (defvar w3m-menubar)
  (defvar w3m-modeline-process-status-on)
  (defvar w3m-show-graphic-icons-in-mode-line)
  (defvar w3m-toolbar)
  (defvar w3m-toolbar-buttons)
  (defvar w3m-use-tab)
  (defvar w3m-use-tab-menubar)
  (defvar w3m-work-buffer-name)
  (defvar w3m-work-buffer-list)
  (autoload 'update-tab-in-gutter "gutter-items")
  (autoload 'w3m-image-type "w3m")
  (autoload 'w3m-retrieve "w3m")
  (autoload 'w3m-setup-tab-menu "w3m-tabmenu"))

;; Dummies to shut some XEmacs variants up.
(eval-when-compile
  (autoload 'unicode-to-char "XEmacs-21.5-b6_and_later")
  (unless (featurep 'mule)
    (defalias 'find-charset 'ignore)))

(require 'path-util)
(require 'poe)
(require 'poem)
(require 'pccl)

;;; Handle coding system:
(defalias 'w3m-find-coding-system (if (fboundp 'find-coding-system)
				      'find-coding-system
				    'ignore))

;; Under XEmacs 21.5-b6 and later, `make-ccl-coding-system' will
;; signal an error if the coding-system has already been defined.
;; To make w3m.elc reloadable, we'll define the function as follows:
;;
;;(defun w3m-make-ccl-coding-system (coding-system args...)
;;  (or (find-coding-system coding-system)
;;      (make-ccl-coding-system coding-system args...)))
(eval-when-compile
  (defmacro w3m-xmas-define-w3m-make-ccl-coding-system ()
    "Make the source form for the function `w3m-make-ccl-coding-system'."
    (if (and (fboundp 'make-ccl-coding-system)
	     (fboundp 'find-coding-system))
	`(defun w3m-make-ccl-coding-system (coding-system mnemonic docstring
							  decoder encoder)
	   ,(concat (documentation 'make-ccl-coding-system)
		    "\n\n\
NOTE: This function is slightly modified from `make-ccl-coding-system'
      to be recallable for the existing coding-systems without errors.")
	   (or (find-coding-system coding-system)
	       (,(symbol-function 'make-ccl-coding-system)
		coding-system mnemonic docstring decoder encoder)))
      '(defalias 'w3m-make-ccl-coding-system 'ignore))))

(w3m-xmas-define-w3m-make-ccl-coding-system)

(eval-and-compile
  (dolist (fn '(coding-priority-list
		coding-system-category
		coding-system-list
		coding-system-name
		coding-system-type
		set-coding-category-system
		set-coding-priority-list))
    (unless (fboundp fn)
      (defalias fn 'ignore))))

;; If pccl.elc has been mis-compiled for XEmacs with MULE, the macro
;; `define-ccl-program' wouldn't be an empty macro because of advice.
(when (and (not (featurep 'mule))
	   (featurep 'advice))
  (ad-unadvise 'define-ccl-program))

(unless (fboundp 'define-ccl-program)
  (defmacro define-ccl-program (&rest args)))

(defmacro w3m-detect-coding-with-priority (from to priority-list)
  (cond
   ((featurep 'mule)
    `(detect-coding-with-priority ,from ,to ,priority-list))
   ((featurep 'file-coding)
    `(detect-coding-region ,from ,to))
   (t
    'w3m-default-coding-system)))

(defun w3m-detect-coding-region (start end &optional priority-list)
  "Detect coding system of the text in the region between START and END.
Return the first possible coding system.

PRIORITY-LIST is a list of coding systems ordered by priority."
  (let (category categories codesys)
    (dolist (codesys priority-list)
      (setq category (or (coding-system-category codesys)
			 (coding-system-name codesys)))
      (unless (assq category categories)
	(push (cons category codesys) categories)))
    (if (consp (setq codesys (w3m-detect-coding-with-priority
			      start end (nreverse categories))))
	(car codesys)
      codesys)))

(defun w3m-decode-coding-string-with-priority (str coding)
  "Decode the string STR which is encoded in CODING.
If CODING is a list, look for the coding system using it as a priority
list."
  (if (listp coding)
      (with-temp-buffer
	(insert str)
	(let* ((orig-category-list (coding-priority-list))
	       (orig-category-systems (mapcar #'coding-category-system
					      orig-category-list))
	       codesys category priority-list)
	  (unwind-protect
	      (progn
		(while coding
		  (setq codesys (car coding)
			coding (cdr coding)
			category (or (coding-system-category codesys)
				     (coding-system-name codesys)))
		  (unless (or (eq (coding-system-type codesys) 'undecided)
			      (assq category priority-list))
		    (set-coding-category-system category codesys)
		    (push category priority-list)))
		(set-coding-priority-list (nreverse priority-list))
		;; `detect-coding-region' always returns `undecided'
		;; ignoring `priority-list' in XEmacs 21.5-b19, but
		;; that's okay.
		(when (consp (setq codesys (detect-coding-region
					    (point-min) (point-max))))
		  (setq codesys (car codesys)))
		(decode-coding-region (point-min) (point-max)
				      (or codesys
					  w3m-default-coding-system
					  w3m-coding-system
					  'iso-2022-7bit))
		(buffer-string))
	    (set-coding-priority-list orig-category-list)
	    (while orig-category-list
	      (set-coding-category-system (car orig-category-list)
					  (car orig-category-systems))
	      (setq orig-category-list (cdr orig-category-list)
		    orig-category-systems (cdr orig-category-systems))))))
    (decode-coding-string str coding)))

(when (and (not (fboundp 'w3m-ucs-to-char))
	   (fboundp 'unicode-to-char)
	   (subrp (symbol-function 'unicode-to-char)))
  (defun w3m-ucs-to-char (codepoint)
    (unicode-to-char codepoint)))

;;; Handle images:

;; Function which returns non-nil when the current display device can
;; show images inline.
(defalias 'w3m-display-graphic-p 'device-on-window-system-p)

(defun w3m-display-inline-images-p ()
  "Returns non-nil when images can be displayed under the present
circumstances."
  (and w3m-display-inline-images (device-on-window-system-p)))

(defvar w3m-should-unoptimize-animated-gifs
  (and (= emacs-major-version 21)
       (or (>= emacs-minor-version 4)
	   (and (= emacs-minor-version 2)
		(>= (or emacs-patch-level emacs-beta-version) 20))))
  "Specify whether w3m should unoptimize animated gif images for showing.
It is applicable to XEmacs 21.2.20 or later, since which only support
to show unoptimized animated gif images.")

(defvar w3m-should-convert-interlaced-gifs t
  "Specify whether w3m should convert interlaced gif images to be non-
interlaced.  There is a known bug in the whole version of XEmacs so
far that it may crash when some kind of an interlaced gif image is
displayed.")

(defvar w3m-gifsicle-program (when (exec-installed-p "gifsicle")
			       "gifsicle")
  "*Name of the gifsicle program used to unoptimize animated gif images
or to convert interlaced gif images to be non-interlaced.")

(defvar w3m-cache-fixed-gif-images nil
  "Cache used to keep fixed gif images.  Fixed gif means that an
unoptimized animated gif or a non-interlaced gif which is converted
from an interlaced gif.  The value is an alist of a URL and a glyph.
Glyph will be nil if there is no need to be unoptimized nor to convert
to be non-interlaced.  Each element should be updated when a URL is
newly retrieved.")

(defvar w3m-cache-fixed-gif-images-max-length 32
  "*Number to limit the length of `w3m-cache-fixed-gif-images'.")

(defvar w3m-animated-gif-maximum-size 1048579
  "*Maximum size (width * height * frames) of animated gif images.  If a
size of an image is larger than this (it might be a bomb!), only the
first frame will be shown.  You can make it to be unlimited with the
value nil if your computer has TerrrrrrraBytes of memories.")

(defun w3m-fix-gif (url data no-cache)
  "Return a glyph image of a gif DATA corresponding to a URL which is
suitable for XEmacs.  It will unoptimize an animated gif or convert
an interlaced gif to be non-interlaced.  Otherwise it returns nil when
there is no need to be unoptimized nor to convert to be non-interlaced
\(or, unfortunately, the unoptimization or the conversion is failed).
It manages the cache `w3m-cache-fixed-gif-images'.  If NO-CACHE is
non-nil, a cached data will not be used and it will be updated by a
new glyph image.  See also the documentation for the variable
`w3m-animated-gif-maximum-size'."
  (let ((cache (assoc url w3m-cache-fixed-gif-images)))
    ;; Move the element which is associated with `url' to the
    ;; top of the cache.
    (when (and cache
	       (not (eq cache (car w3m-cache-fixed-gif-images))))
      (setq w3m-cache-fixed-gif-images
	    (cons cache (delq cache w3m-cache-fixed-gif-images))))
    (if (or no-cache
	    (not cache))
	(with-temp-buffer
	  (let ((coding-system-for-read 'binary)
		(coding-system-for-write 'binary)
		should-be-non-interlaced should-unoptimize size1 size2 glyph)
	    (insert data)
	    (goto-char (point-min))
	    (when (looking-at "GIF8[79]")
	      (call-process-region (point-min) (point-max)
				   w3m-gifsicle-program
				   t t nil "--info")
	      (goto-char (point-min))
	      ;; Check whether a `data' is interlaced.
	      (setq should-be-non-interlaced
		    (re-search-forward
		     "  \\+ image #[0-9]+ \\([0-9]+x[0-9]+\\).* interlaced"
		     nil t))
	      (goto-char (point-min))
	      ;; Check whether a `data' is optimized or larger than
	      ;; the value of `w3m-animated-gif-maximum-size'.
	      (when (and w3m-animated-gif-maximum-size
			 (looking-at ".+ \\([0-9]+\\) images\r?$"))
		(setq size1 (string-to-number (match-string 1)))
		(forward-line 1)
		(unless (and (looking-at ".+ \\([0-9]+\\)x\\([0-9]+\\)\r?$")
			     (natnump (setq size1 (* size1
						     (string-to-number
						      (match-string 1)))))
			     (<= size1 w3m-animated-gif-maximum-size)
			     (natnump (setq size1 (* size1
						     (string-to-number
						      (match-string 2)))))
			     (<= size1 w3m-animated-gif-maximum-size))
		  ;; It should be truncated to be only one frame.
		  (setq should-unoptimize "#0"))
		(setq size1 nil)
		(while (and (not should-unoptimize)
			    (re-search-forward
			     "  \\+ image #[0-9]+ \\([0-9]+x[0-9]+\\)"
			     nil t))
		  (if size1
		      (if (string-equal size1 (setq size2 (match-string 1)))
			  (setq size1 size2)
			(setq should-unoptimize "--unoptimize"))
		    (setq size1 (match-string 1)))))
	      (when (or should-unoptimize should-be-non-interlaced)
		(erase-buffer)
		(insert data)
		;; Unoptimize anyway.
		(if should-unoptimize
		    (call-process-region (point-min) (point-max)
					 w3m-gifsicle-program
					 t t nil should-unoptimize
					 "--no-interlace")
		  (call-process-region (point-min) (point-max)
				       w3m-gifsicle-program
				       t t nil "--no-interlace"))
		(goto-char (point-min))
		(when (or (looking-at "GIF8[79]")
			  ;; Unoptimization is failed. :-<
			  ;; Attempt to extract the first frame.
			  (progn
			    (erase-buffer)
			    (insert data)
			    (call-process-region (point-min) (point-max)
						 w3m-gifsicle-program
						 t t nil "#0" "--no-interlace")
			    (goto-char (point-min))
			    (looking-at "GIF8[79]")))
		  ;; Perhaps the unoptimization is succeeded.
		  (setq glyph
			(make-glyph (vector 'gif :data (buffer-string)))))))
	    ;; Update a cache.
	    (if cache
		(setcdr cache glyph)
	      (push (cons url glyph) w3m-cache-fixed-gif-images)
	      (let ((maxlen w3m-cache-fixed-gif-images-max-length))
		(when (and (integerp maxlen)
			   (>= maxlen 1)
			   (> (length w3m-cache-fixed-gif-images) maxlen))
		  (setcdr (nthcdr (1- maxlen) w3m-cache-fixed-gif-images)
			  nil))))
	    glyph))
      ;; Use a cached glyph.
      (cdr cache))))

(defsubst w3m-make-glyph (data type)
  (or (and (eq type 'xbm)
	   (let (width height content)
	     (with-temp-buffer
	       (insert data)
	       (goto-char (point-min))
	       (if (re-search-forward "width[ \t]+\\([0-9]+\\)")
		   (setq width (string-to-int (match-string 1))))
	       (if (re-search-forward "height[ \t]+\\([0-9]+\\)")
		   (setq height (string-to-int (match-string 1))))
	       (while (re-search-forward "0x\\(..\\)" nil t)
		 (setq content (cons
				(string-to-int
				 (match-string 1) 16) content)))
	       (setq content (concat (nreverse content))))
	     (make-glyph (vector 'xbm :data (list width height content)))))
      (make-glyph (vector type :data data))))

(defun w3m-create-image (url &optional no-cache referer size handler)
  "Retrieve data from URL and create an image object.
If optional argument NO-CACHE is non-nil, cache is not used.
If second optional argument REFERER is non-nil, it is used as Referer: field.
Third optional argument SIZE is currently ignored."
  (if (not handler)
      (w3m-process-with-wait-handler
	(w3m-create-image url no-cache referer handler))
    (lexical-let ((url url)
		  (set-size size)
		  (no-cache no-cache)
		  size)
      (w3m-process-do-with-temp-buffer
	  (type (condition-case err
		    (w3m-retrieve url 'raw no-cache nil referer handler)
		  (error (message "While retrieving %s: %s" url err) nil)))
	(when type
	  (let ((data (buffer-string))
		glyph)
	    (setq glyph
		  (when (w3m-image-type-available-p
			 (setq type (w3m-image-type type)))
		    (or (and (eq type 'gif)
			     (or w3m-should-unoptimize-animated-gifs
				 w3m-should-convert-interlaced-gifs)
			     w3m-gifsicle-program
			     (w3m-fix-gif url data no-cache))
			(w3m-make-glyph data type))))
	    (if (and w3m-resize-images set-size)
		(progn
		  (setq size (cons (glyph-width glyph)
				   (glyph-height glyph)))
		  (if (and (null (car set-size)) (cdr set-size))
		      (setcar set-size
			      (/ (* (car size) (cdr set-size))
				 (cdr size))))
		  (if (and (null (cdr set-size)) (car set-size))
		      (setcdr set-size
			      (/ (* (cdr size) (car set-size))
				 (car size))))
		  (if (or (not (eq (car size)
				   (car set-size))) ;; width is different
			  (not (eq (cdr size)
				   (cdr set-size)))) ;; height is different
		      (lexical-let ((type type))
			(w3m-process-do
			    (resized (w3m-resize-image
				      data
				      (car set-size)(cdr set-size)
				      handler))
			  (w3m-make-glyph resized type)))
		    glyph))
	      glyph)))))))

(defun w3m-create-resized-image (url rate &optional referer size handler)
  "Resize an cached image object.
URL is the image file's url.
RATE is resize percentage.
If REFERER is non-nil, it is used as Referer: field.
If SIZE is non-nil, its car element is used as width
and its cdr element is used as height."
  (if (not handler)
      (w3m-process-with-wait-handler
	(w3m-create-image url nil referer size handler))
    (lexical-let ((url url)
		  (rate rate)
		  fmt data)
      (w3m-process-do-with-temp-buffer
	  (type (w3m-retrieve url 'raw nil nil referer handler))
	(when (w3m-image-type-available-p (setq type (w3m-image-type type)))
	  (setq data (buffer-string)
		fmt type)
	  (w3m-process-do
	      (resized (w3m-resize-image-by-rate data rate handler))
	    (when resized
	      (or (and (eq fmt 'gif)
		       (or w3m-should-unoptimize-animated-gifs
			   w3m-should-convert-interlaced-gifs)
		       w3m-gifsicle-program
		       (let (w3m-cache-fixed-gif-images)
			 (w3m-fix-gif url resized t)))
		  (w3m-make-glyph resized fmt)))))))))

(defun w3m-insert-image (beg end image &rest args)
  "Display IMAGE in the current buffer.
A buffer string between BEG and END are replaced with IMAGE."
  (let (glyphs)
    (map-extents
     (lambda (extent maparg)
       (push (extent-end-glyph extent) glyphs)
       (set-extent-end-glyph extent nil)
       nil)
     nil beg beg nil nil 'w3m-xmas-icon)
    ;; Display an image on the right hand.
    (push image glyphs)
    (when (extent-at end nil 'invisible nil 'at)
      (setq end (next-single-property-change end 'invisible))
      (map-extents
       (lambda (extent maparg)
	 (push (extent-end-glyph extent) glyphs)
	 (set-extent-end-glyph extent nil)
	 nil)
       nil end end nil nil 'w3m-xmas-icon))
    (set-extent-properties (make-extent beg end) (list 'w3m-xmas-icon t
						       'invisible t))
    (while glyphs
      (set-extent-properties (make-extent end end)
			     (list 'w3m-xmas-icon t
				   'end-glyph (pop glyphs))))))

(defun w3m-remove-image (beg end)
  "Remove images between BEG and END."
  (map-extents (lambda (extent maparg)
		 (delete-extent extent)
		 nil)
	       nil beg end nil 'end-closed 'w3m-xmas-icon))

(defun w3m-image-type-available-p (image-type)
  "Return non-nil if an image with IMAGE-TYPE can be displayed inline."
  (and (device-on-window-system-p)
       (featurep image-type)))

;;; Toolbar:
(defcustom w3m-use-toolbar (and (featurep 'toolbar) t)
  "Non-nil activates toolbar of w3m."
  :group 'w3m
  :type 'boolean)

(defun w3m-xmas-make-toolbar-buttons (buttons)
  (dolist (button buttons)
    (let ((up (expand-file-name (concat button "-up.xpm")
				w3m-icon-directory))
	  (down (expand-file-name (concat button "-down.xpm")
				  w3m-icon-directory))
	  (disabled (expand-file-name (concat button "-disabled.xpm")
				      w3m-icon-directory))
	  (icon (intern (concat "w3m-toolbar-" button "-icon"))))
      (if (file-exists-p up)
	  (set icon
	       (toolbar-make-button-list
		up
		(and (file-exists-p down) down)
		(and (file-exists-p disabled) disabled)))
	(error "Icon file %s not found" up)))))

(defun w3m-setup-toolbar ()
  "Setup toolbar."
  (when (and w3m-use-toolbar
	     w3m-icon-directory
	     (file-directory-p w3m-icon-directory)
	     (file-exists-p (expand-file-name "antenna-up.xpm"
					      w3m-icon-directory)))
    (w3m-xmas-make-toolbar-buttons w3m-toolbar-buttons)
    (set-specifier default-toolbar
		   (cons (current-buffer) w3m-toolbar))
    t))

(defun w3m-update-toolbar ()
  "Update toolbar."
  (when (and w3m-use-toolbar
	     (or (and (boundp 'w3m-toolbar-antenna-icon)
		      (symbol-value 'w3m-toolbar-antenna-icon))
		 (w3m-setup-toolbar)))
    (set-specifier default-toolbar
		   (cons (current-buffer) w3m-toolbar))))

;;; Menu:
(defun w3m-setup-menu ()
  "Define menubar buttons for XEmacs."
  (when (and (featurep 'menubar)
	     current-menubar
	     (not (assoc (car w3m-menubar) current-menubar)))
    (when w3m-use-tab-menubar (w3m-setup-tab-menu))
    (set-buffer-menubar (cons w3m-menubar current-menubar))))

;;; Widget:
(eval-when-compile (require 'wid-edit))

(defun w3m-xmas-define-missing-widgets ()
  "Define some missing widgets."
  (unless (get 'coding-system 'widget-type)
    ;; The following codes are imported from wid-edit.el of Emacs 20.7.

    (defvar widget-coding-system-prompt-value-history nil
      "History of input to `widget-coding-system-prompt-value'.")

    (defun widget-coding-system-prompt-value (widget prompt value unbound)
      ;; Read coding-system from minibuffer.
      (intern
       (completing-read (format "%s (default %s) " prompt value)
			(mapcar (lambda (sym)
				  (list (symbol-name sym)))
				(coding-system-list)))))

    (defun widget-coding-system-action (widget &optional event)
      ;; Read a file name from the minibuffer.
      (let ((answer
	     (eval (list 'widget-coding-system-prompt-value
			 widget
			 (widget-apply widget :menu-tag-get)
			 (widget-value widget)
			 t))))
	(widget-value-set widget answer)
	(widget-apply widget :notify widget event)
	(widget-setup))))

    (define-widget 'coding-system 'symbol
      "A MULE coding-system."
      :format "%{%t%}: %v"
      :tag "Coding system"
      :prompt-history 'widget-coding-system-prompt-value-history
      :prompt-value 'widget-coding-system-prompt-value
      :action 'widget-coding-system-action)

  (unless (get 'other 'widget-type)
    ;; The following definition is imported from wid-edit.el of Emacs 20.7.
    (define-widget 'other 'sexp
      "Matches any value, but doesn't let the user edit the value.
This is useful as last item in a `choice' widget.
You should use this widget type with a default value,
as in (other DEFAULT) or (other :tag \"NAME\" DEFAULT).
If the user selects this alternative, that specifies DEFAULT
as the value."
      :tag "Other"
      :format "%t%n"
      :value 'other)))

(eval-after-load "wid-edit" '(w3m-xmas-define-missing-widgets))

;;; Header line:
(defvar w3m-header-line-map (make-sparse-keymap))
(define-key w3m-header-line-map 'button2 'w3m-goto-url)

;;; Gutter:
(defcustom w3m-xmas-show-current-title-in-buffer-tab
  (and (boundp 'gutter-buffers-tab-enabled)
       gutter-buffers-tab-enabled)
  "If non-nil, show the title strings in the buffers tab.
It has no effect if your XEmacs does not support the gutter items."
  :group 'w3m
  :type 'boolean
  :get (lambda (symbol)
	 (if (boundp 'gutter-buffers-tab-enabled)
	     (default-value symbol)))
  :set (lambda (symbol value)
	 (prog2
	     (or (boundp 'gutter-buffers-tab-enabled)
		 (setq value nil))
	     (set-default symbol value)
	   (if value
	       (add-hook 'w3m-display-functions 'w3m-xmas-update-tab-in-gutter)
	     (remove-hook 'w3m-display-functions 'w3m-xmas-update-tab-in-gutter))
	   (condition-case nil
	       (progn
		 (if value
		     (ad-enable-advice
		      'format-buffers-tab-line 'around
		      'w3m-xmas-show-current-title-in-buffer-tab)
		   (ad-disable-advice
		    'format-buffers-tab-line 'around
		    'w3m-xmas-show-current-title-in-buffer-tab))
		 (if (boundp 'gutter-buffers-tab-enabled)
		     (mapc #'update-tab-in-gutter (frame-list))))
	     (error)))))

(when (boundp 'gutter-buffers-tab-enabled)
  (defadvice format-buffers-tab-line
    (around w3m-xmas-show-current-title-in-buffer-tab (buffer) activate)
    "Advised by emacs-w3m.
Show the current title string in the buffer tab.  Unfortunately,
existing XEmacs does not support showing non-ascii characters.  When a
title contains non-ascii characters, show a url name by default."
    (with-current-buffer buffer
      (if (and w3m-xmas-show-current-title-in-buffer-tab
	       (symbol-value 'gutter-buffers-tab-enabled)
	       (eq 'w3m-mode major-mode))
	  (let* ((len (specifier-instance
		       (symbol-value 'buffers-tab-default-buffer-line-length)))
		 (name (if (and (stringp w3m-current-title)
				(string-match "^[ -~]+$" w3m-current-title))
			   w3m-current-title
			 (if (stringp w3m-current-url)
			     (directory-file-name
			      (if (string-match "^[^/:]+:/+" w3m-current-url)
				  (substring w3m-current-url (match-end 0))
				w3m-current-url))
			   "")))
		 (num (if (string-match ".*<\\(.+\\)>$" (buffer-name buffer))
			  (match-string 1 (buffer-name buffer))))
		 (lnum (length num)))
	    (setq ad-return-value
		  (if num
		      (if (and (> len 0)
			       (> (+ (length name) lnum) len))
			  (concat "[" num "]"
				  (substring name 0 (max 0 (- len lnum 5 )))
				  "...")
			(concat "[" num "]" name))
		    (if (and (> len 0)
			     (> (length name) len))
			(concat (substring name 0 (max 0 (- len 3))) "...")
		      name))))
	ad-do-it)))

  (if w3m-xmas-show-current-title-in-buffer-tab
      (ad-enable-advice 'format-buffers-tab-line 'around
			'w3m-xmas-show-current-title-in-buffer-tab)
    (ad-disable-advice 'format-buffers-tab-line 'around
		       'w3m-xmas-show-current-title-in-buffer-tab))

  (defun w3m-xmas-setup-tab-in-gutter ()
    "Set up buffers tab in the gutter."
    (set-specifier default-gutter-visible-p
		   (and w3m-use-tab gutter-buffers-tab-enabled t)
		   (current-buffer)))
  (add-hook 'w3m-mode-setup-functions 'w3m-xmas-setup-tab-in-gutter)
  (add-hook 'w3m-select-buffer-mode-hook 'w3m-xmas-setup-tab-in-gutter)

  (defun w3m-xmas-update-tab-in-gutter (&rest args)
    "Update the tab control in the gutter area."
    (when (and w3m-use-tab gutter-buffers-tab-enabled)
      (update-tab-in-gutter (selected-frame))))
  (add-hook 'w3m-display-functions 'w3m-xmas-update-tab-in-gutter))

;;; Graphic icons:
(defcustom w3m-space-before-modeline-icon ""
  "String of space character(s) to be put in front of the modeline icon.
It may be better to use one or more spaces if you are using oblique or
italic font in the modeline."
  :group 'w3m
  :type 'string)

;; Glyph images to be displayed in the modeline.
(defvar w3m-modeline-process-status-on-icon nil)
(defvar w3m-modeline-image-status-on-icon nil)
(defvar w3m-modeline-status-off-icon nil)
(defvar w3m-modeline-ssl-image-status-on-icon nil)
(defvar w3m-modeline-ssl-status-off-icon nil)

(defun w3m-initialize-graphic-icons (&optional force)
  "Make icon images which will be displayed in the modeline."
  (interactive "P")
  (let ((defs '((w3m-modeline-status-off-icon
		 "state-00.xpm"
		 w3m-modeline-status-off)
		(w3m-modeline-image-status-on-icon
		 "state-01.xpm"
		 w3m-modeline-image-status-on)
		(w3m-modeline-ssl-status-off-icon
		 "state-10.xpm"
		 w3m-modeline-ssl-status-off)
		(w3m-modeline-ssl-image-status-on-icon
		 "state-11.xpm"
		 w3m-modeline-ssl-image-status-on)))
	def icon file status extent keymap)
    (while defs
      (setq def (car defs)
	    defs (cdr defs)
	    icon (car def)
	    file (nth 1 def)
	    status (nth 2 def))
      (if (and w3m-show-graphic-icons-in-mode-line
	       (device-on-window-system-p)
	       (featurep 'xpm)
	       w3m-icon-directory
	       (file-directory-p w3m-icon-directory)
	       (file-exists-p
		(setq file (expand-file-name file w3m-icon-directory))))
	  (progn
	    (when (or force (not (symbol-value icon)))
	      (unless extent
		(setq extent (make-extent nil nil)
		      keymap (make-sparse-keymap))
		(define-key keymap 'button2
		  (make-modeline-command-wrapper 'w3m-reload-this-page))
		(set-extent-keymap extent keymap)
		(set-extent-property extent 'help-echo
				     "button2 reloads this page"))
	      (set icon
		   (cons extent
			 (make-glyph
			  (make-image-instance (vector 'xpm :file file))))))
	    (when (stringp (symbol-value status))
	      ;; Save the original status strings as properties.
	      (put status 'string (symbol-value status)))
	    (set status (list '("" w3m-space-before-modeline-icon) icon)))
	;; Don't use graphic icons.
	(when (get status 'string)
	  (set status (get status 'string)))))
    ;; Spinner.
    (if (and w3m-show-graphic-icons-in-mode-line
	     (device-on-window-system-p)
	     (featurep 'gif)
	     w3m-icon-directory
	     (file-directory-p w3m-icon-directory)
	     (file-exists-p
	      (setq file (expand-file-name "spinner.gif"
					   w3m-icon-directory))))
	(progn
	  (when (or force (not w3m-modeline-process-status-on-icon))
	    (setq extent (make-extent nil nil)
		  keymap (make-sparse-keymap))
	    (define-key keymap 'button2
	      (make-modeline-command-wrapper 'w3m-process-stop))
	    (set-extent-keymap extent keymap)
	    (set-extent-property extent 'help-echo
				 "button2 kills the current process")
	    (setq
	     w3m-modeline-process-status-on-icon
	     (cons
	      extent
	      (make-glyph
	       (if w3m-gifsicle-program
		   ;; XEmacs doesn't support a transparent color on gifs,
		   ;; so we should replace the background color of the image
		   ;; with the modeline's one.
		   (make-image-instance
		    (vector
		     'gif
		     :data
		     (let ((coding-system-for-read 'binary)
			   (coding-system-for-write 'binary)
			   format-alist)
		       (with-temp-buffer
			 (insert-file-contents file)
			 (goto-char (point-max))
			 (call-process-region
			  (point-min) (point-max) w3m-gifsicle-program t t nil
			  "--careful" "--delay" "10" "--loopcount=forever"
			  "--change-color" "255,255,255"
			  (mapconcat
			   (lambda (c) (number-to-string (% c 256)))
			   (color-rgb-components
			    (face-background 'modeline))
			   ","))
			 (buffer-string)))))
		 (make-image-instance (vector 'gif :file file)))))))
	  (when (stringp w3m-modeline-process-status-on)
	    ;; Save the original status string as a property.
	    (put 'w3m-modeline-process-status-on 'string
		 w3m-modeline-process-status-on))
	  (setq w3m-modeline-process-status-on
		'(("" w3m-space-before-modeline-icon)
		  w3m-modeline-process-status-on-icon)))
      ;; Don't use spinner.
      (when (get 'w3m-modeline-process-status-on 'string)
	(setq w3m-modeline-process-status-on
	      (get 'w3m-modeline-process-status-on 'string))))))

;;; Miscellaneous:
(if (featurep 'mule)
    (defalias 'multibyte-string-p 'stringp)
  (defalias 'multibyte-string-p 'ignore))

(if (featurep 'mule)
    (defun w3m-mule-unicode-p ()
      "Check the existence as charsets of mule-unicode."
      (and (find-charset 'mule-unicode-0100-24ff)
	   (find-charset 'mule-unicode-2500-33ff)
	   (find-charset 'mule-unicode-e000-ffff)))
  (defalias 'w3m-mule-unicode-p 'ignore))

(if (condition-case nil
	(progn
	  (unless (or itimer-process itimer-timer)
	    (itimer-driver-start))
	  ;; Check whether there is a bug to which the difference of
	  ;; the present time and the time when the itimer driver was
	  ;; woken up is subtracted from the initial itimer value.
	  (let* ((inhibit-quit t)
		 (ctime (current-time))
		 (itimer-timer-last-wakeup
		  (prog1
		      ctime
		    (setcar ctime (1- (car ctime)))))
		 (itimer-list nil)
		 (itimer (start-itimer "w3m-run-at-time" 'ignore 5)))
	    (sleep-for 0.1) ;; Accept the timeout interrupt.
	    (prog1
		(> (itimer-value itimer) 0)
	      (delete-itimer itimer))))
      (error nil))
    (if (condition-case nil
	    (require 'timer-funcs)
	  (error nil))
	(defalias 'w3m-run-at-time 'run-at-time)
      (defun w3m-run-at-time (time repeat function &rest args)
	"Emulating function run as `run-at-time'.
TIME should be nil meaning now, or a number of seconds from now.
Return an itimer object which can be used in either `delete-itimer'
or `cancel-timer'."
	(apply #'start-itimer "w3m-run-at-time"
	       function (if time (max time 1e-9) 1e-9)
	       repeat nil t args)))
  (defun w3m-run-at-time (time repeat function &rest args)
    "Emulating function run as `run-at-time' in the right way.
TIME should be nil meaning now, or a number of seconds from now.
Return an itimer object which can be used in either `delete-itimer'
or `cancel-timer'."
    (let ((itimers (list nil)))
      (setcar
       itimers
       (apply #'start-itimer "w3m-run-at-time"
	      (lambda (itimers repeat function &rest args)
		(let ((itimer (car itimers)))
		  (if repeat
		      (progn
			(set-itimer-function
			 itimer
			 (lambda (itimer repeat function &rest args)
			   (set-itimer-restart itimer repeat)
			   (set-itimer-function itimer function)
			   (set-itimer-function-arguments itimer args)
			   (apply function args)))
			(set-itimer-function-arguments
			 itimer
			 (append (list itimer repeat function) args)))
		    (set-itimer-function
		     itimer
		     (lambda (itimer function &rest args)
		       (delete-itimer itimer)
		       (apply function args)))
		    (set-itimer-function-arguments
		     itimer
		     (append (list itimer function) args)))))
	      1e-9 (if time (max time 1e-9) 1e-9)
	      nil t itimers repeat function args)))))

(unless (fboundp 'cancel-timer)
  (defun cancel-timer (timer)
    "Remove TIMER from the list of active timers."
    (or (itimerp timer)
	(error "Invalid timer"))
    (delete-itimer timer)
    nil))

(when (featurep 'mule)
  (defun w3m-window-hscroll (&optional window)
    "Replacement of `window-hscroll' for XEmacs-Mule.
XEmacs does not work correctly in the display control in case buffer
contains characters of various width.  This function does not
necessarily solve the problem completely."
    (let ((hs (window-hscroll window))
	  (spos (point-at-bol))
	  (epos (point-at-eol))
	  (buf (window-buffer window)))
      (save-selected-window
	(save-excursion
	  (set-buffer buf)
	  (beginning-of-line)
	  (condition-case nil
	      (forward-char hs)
	    (error (goto-char (point-max))))
	  (if (< epos (point))
	      (+ hs (- (string-width (buffer-substring spos epos))
		       (- epos spos)))
	    (string-width (buffer-substring spos (point))))))))

  (defun w3m-current-column ()
    "Replacement of `current-column' for XEmacs-Mule.
XEmacs does not work correctly in the display control in case buffer
contains characters of various width.  This function does not
necessarily solve the problem completely."
    (- (point) (point-at-bol)))

  (defun w3m-set-window-hscroll (window columns)
    "Replacement of `set-window-hscroll' for XEmacs-Mule.
XEmacs does not work correctly in the display control in case buffer
contains characters of various width.  This function does not
necessarily solve the problem completely."
    (save-excursion
      (move-to-column (max columns 0))
      (if (> columns (current-column))
	  (set-window-hscroll window (+ (- (point-at-eol) (point-at-bol))
					(- columns (current-column))))
	(set-window-hscroll window (- (point) (point-at-bol))))))
  )

(provide 'w3m-xmas)

;;; w3m-xmas.el ends here