;;; browse-url.el --- ask a WWW browser to load a URL

;; Copyright 1995 Free Software Foundation, Inc.

;; Author: Denis Howe <dbh@doc.ic.ac.uk>
;; Maintainer: Denis Howe <dbh@doc.ic.ac.uk>
;; Created: 03 Apr 1995
;; Version: 0.38 18 Jun 1996
;; Keywords: hypertext
;; X-Home page: http://wombat.doc.ic.ac.uk/

;; 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) any later version.

;; GNU Emacs 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 GNU Emacs; see the file COPYING.  If not, write to the
;; Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; Commentary:

;; The latest version of this package should be available from
;; <URL:http://wombat.doc.ic.ac.uk/emacs/browse-url.el>.

;; This package provides functions which read a URL (Uniform Resource
;; Locator) from the minibuffer, defaulting to the URL around point,
;; and ask a World-Wide Web browser to load it.  It can also load the
;; URL associated with the current buffer.  Different browsers use
;; different methods of remote control so there is one function for
;; each supported browser.  If the chosen browser is not running, it
;; is started.  Currently there is support for:

;; Function              Browser     Earliest version
;; browse-url-netscape   Netscape    1.1b1	   
;; browse-url-mosaic     XMosaic     <= 2.4
;; browse-url-cci        XMosaic     2.5
;; browse-url-w3         w3          0
;; browse-url-iximosaic  IXI Mosaic  ?
;; browse-url-lynx-*	 Lynx	     0
;; browse-url-grail      Grail       0.3b1

;; Note that versions of Netscape before 1.1b1 did not have remote
;; control.  <URL:http://www.netscape.com/newsref/std/x-remote.html>
;; and <URL:http://www.netscape.com/info/APIs/>.

;; Netscape can cache Web pages so it may be necessary to tell it to
;; reload the current page if it has changed (e.g. if you have edited
;; it).  There is currently no perfect automatic solution to this.

;; Netscape allows you to specify the id of the window you want to
;; control but which window DO you want to control and how do you
;; discover its id?

;; If using XMosaic before version 2.5, check the definition of
;; browse-url-usr1-signal below.
;; <URL:http://www.ncsa.uiuc.edu/SDG/Software/XMosaic/remote-control.html>

;; XMosaic version 2.5 introduced Common Client Interface allowing you
;; to control mosaic through Unix sockets.
;; <URL:http://www.ncsa.uiuc.edu/SDG/Software/XMosaic/CCI/cci-spec.html>

;; William M. Perry's excellent "w3" WWW browser for
;; Emacs <URL:ftp://cs.indiana.edu/pub/elisp/w3/>
;; has a function w3-follow-url-at-point, but that
;; doesn't let you edit the URL like browse-url.

;; I recommend Nelson Minar <nelson@santafe.edu>'s excellent
;; html-helper-mode.el for editing HTML and thank Nelson for
;; his many useful comments on this code.
;; <URL:http://www.santafe.edu/~nelson/hhm-beta/>

;; This package generalises function html-previewer-process in Marc
;; Andreessen <marca@ncsa.uiuc.edu>'s html-mode (LCD
;; modes/html-mode.el.Z) and provides better versions of the URL
;; functions in Michelangelo Grigni <mic@cs.ucsd.edu>'s ffap.el
;; (find-file-at-point) <URL:ftp://cs.ucsd.edu:/pub/mic/>.  The huge
;; hyperbole package also contains similar functions.

;; Grail is the freely available WWW browser implemented in Python, a
;; cool object-oriented freely available interpreted language.  Grail
;; 0.3b1 was the first version to have remote control as distributed.
;; For more information on Grail see
;; <URL:http://monty.cnri.reston.va.us/> and for more information on
;; Python see <url:http://www.python.org/>.  Grail support in
;; browse-url.el written by Barry Warsaw <bwarsaw@python.org>.

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Help!

;; Can you write and test some code for the Macintrash and Windoze
;; Netscape remote control APIs?  (See the URL above).

;; Do any other browsers have remote control?

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Installation

;; Put the following in your ~/.emacs file:
;;
;; (autoload 'browse-url-at-point "browse-url"
;;   "Ask a WWW browser to load the URL at or before point." t)
;; (autoload 'browse-url-at-mouse "browse-url"
;;   "Ask a WWW browser to load a URL clicked with the mouse." t)
;; (autoload 'browse-url-of-buffer "browse-url"
;;   "Ask a WWW browser to display BUFFER." t)
;; (autoload 'browse-url-of-file "browse-url"
;;   "Ask a WWW browser to display FILE." t)
;; (autoload 'browse-url-of-dired-file "browse-url"
;;   "In Dired, ask a WWW browser to display the file named on this line." t)

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Usage

;; To display the URL at or before point:
;; M-x browse-url-at-point RET

;; To display a URL by shift-clicking on it, put this in your ~/.emacs
;; file:
;;	(global-set-key [S-mouse-1] 'browse-url-at-mouse)

;; To display the current buffer in a web browser:
;; M-x browse-url-of-buffer RET

;; In Dired, to display the file named on the current line:
;; M-x browse-url-of-dired-file RET

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Customisation (~/.emacs)

;; To see what variables are available for customization, type
;; `M-x set-variable browse-url TAB'.

;; Bind the browse-url commands to keys with the `C-c C-z' prefix
;; (as used by html-helper-mode):
;;	(global-set-key "\C-c\C-z." 'browse-url-at-point)
;;	(global-set-key "\C-c\C-zb" 'browse-url-of-buffer)
;;	(global-set-key "\C-c\C-zu" 'browse-url)
;;	(global-set-key "\C-c\C-zv" 'browse-url-of-file)
;;	(add-hook 'dired-mode-hook
;;		  (function (lambda ()
;;			      (local-set-key "\C-c\C-zf" 'browse-url-of-dired-file))))

;; Browse URLs in mail messages by clicking mouse-2:
;;	(add-hook 'rmail-mode-hook (function (lambda () ; rmail-mode startup
;;	  (define-key rmail-mode-map [mouse-2] 'browse-url-at-mouse))))

;; Browse URLs in Usenet messages by clicking mouse-2:
;;	(eval-after-load "gnus"
;;	  '(define-key gnus-article-mode-map [mouse-2] 'browse-url-at-mouse))

;; Use the Emacs w3 browser when not running under X11:
;;	(or (eq window-system 'x)
;;	    (setq browse-url-browser-function 'browse-url-w3))

;; To always save modified buffers before displaying the file in a browser:
;;	(setq browse-url-save-file t)

;; To get round the Netscape caching problem, you could EITHER have
;; write-file in html-helper-mode make Netscape reload the document:
;;
;;	(autoload 'browse-url-netscape-reload "browse-url"
;;	  "Ask a WWW browser to redisplay the current file." t)
;;	(add-hook 'html-helper-mode-hook
;;		  (function (lambda ()
;;		     (add-hook 'local-write-file-hooks
;;			       (function (lambda ()
;;				  (let ((local-write-file-hooks))
;;				    (save-buffer))
;;				  (browse-url-netscape-reload)
;;				  t))			; => file written by hook
;;			       t))))			; append to l-w-f-hooks
;;
;; OR have browse-url-of-file ask Netscape to load and then reload the
;; file:
;;
;;	(add-hook 'browse-url-of-file-hook 'browse-url-netscape-reload)

;; You may also want to customise browse-url-netscape-arguments, e.g.
;;	(setq browse-url-netscape-arguments '("-install"))
;;
;; or similarly for mosaic. 

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;; Change Log:

;; 0.00 03 Apr 1995 Denis Howe <dbh@doc.ic.ac.uk>
;;	Created.

;; 0.01 04 Apr 1995
;;	All names start with "browse-url-".  Added provide.

;; 0.02 05 Apr 1995
;;	Save file at start of browse-url-of-file.
;;	Use start-process instead of start-process-shell-command.

;; 0.03 06 Apr 1995
;;	Add browse-url-netscape-reload, browse-url-netscape-send.
;;	browse-url-of-file save file option.

;; 0.04 08 Apr 1995
;;	b-u-file-url separate function.  Change b-u-filename-alist
;;	default.

;; 0.05 09 Apr 1995
;;	Added b-u-of-file-hook.

;; 0.06 11 Apr 1995
;;	Improved .emacs suggestions and documentation.

;; 0.07 13 Apr 1995
;;	Added browse-url-interactive-arg optional prompt.

;; 0.08 18 Apr 1995
;;	Exclude final "." from browse-url-regexp.

;; 0.09 21 Apr 1995
;;	Added mouse-set-point to browse-url-interactive-arg.

;; 0.10 24 Apr 1995
;;	Added Mosaic signal sending variations.
;;	Thanks Brian K Servis <servis@ecn.purdue.edu>.
;;	Don't use xprop for Netscape.

;; 0.11 25 Apr 1995
;;	Fix reading of ~/.mosaicpid.  Thanks Dag.H.Wanvik@kvatro.no.

;; 0.12 27 Apr 1995
;;	Interactive prefix arg => URL *after* point.
;;	Thanks Michelangelo Grigni <mic@cs.ucsd.edu>.
;;	Added IXI Mosaic support.
;;	Thanks David Karr <dkarr@nmo.gtegsc.com>.

;; 0.13 28 Apr 1995
;;	Exclude final [,;] from browse-url-regexp.

;; 0.14 02 May 1995
;;	Provide browser argument variables.

;; 0.15 07 May 1995
;;	More Netscape options.  Thanks Peter Arius
;;	<arius@immd2.informatik.uni-erlangen.de>.

;; 0.16 17 May 1995
;;	Added browse-url-at-mouse.
;;	Thanks Wayne Mesard <wmesard@sgi.com>

;; 0.17 27 Jun 1995
;;	Renamed browse-url-at-point to browse-url-url-at-point.
;;	Added browse-url-at-point.
;;	Thanks Jonathan Cano <cano@patch.tandem.com>.

;; 0.18 16 Aug 1995
;;	Fixed call to browse-url-url-at-point in browse-url-at-point.
;;	Thanks Eric Ding <ericding@San-Jose.ate.slb.com>.

;; 0.19 24 Aug 1995
;;	Improved documentation.
;;	Thanks Kevin Rodgers <kevin.rodgers@ihs.com>.

;; 0.20 31 Aug 1995
;;	browse-url-of-buffer to handle file-less buffers.
;;	browse-url-of-dired-file browses current file in dired.
;;	Thanks Kevin Rodgers <kevin.rodgers@ihs.com>.

;; 0.21 09 Sep 1995
;;	XMosaic CCI functions.
;;	Thanks Marc Furrer <Marc.Furrer@di.epfl.ch>.

;; 0.22 13 Sep 1995
;;	Fixed new-window documentation and added to browse-url-cci.
;;	Thanks Dilip Sequeira <djs@dcs.ed.ac.uk>.

;; 0.23 10 Nov 1995
;;	Added b-u-lynx.  Thanks Steven L. Baur <steve@miranova.com>.

;; 0.24 22 Nov 1995
;;	Renamed b-u-netscape command to b-u-netscape-send.
;;	Added b-u-netscape-command variable.

;; 0.25 03 Dec 1995
;;	Added event-buffer and event-point for XEmacs compatibility.
;;	Thanks Eric Engstrom <engstrom@src.honeywell.com>

;; 0.26 13 Jan 1996
;;	Changed b-u-lynx to b-u-lynx-xterm, added b-u-lynx-emacs to
;;	run Lynx in an Emacs buffer under terminal-emulator.
;;	Thanks Jari Aalto <jaalto@tre.tele.nokia.fi>

;; 0.27 27 Feb 1996
;;	Changed event-buffer and event-point from macros to functions.
;;	Other fixes for byte-compilation.

;; 0.28 07 Mar 1996
;;	browse-url-lynx-emacs uses term.el instead of terminal.el.

;; 0.29 13 Mar 1996
;;	Added browse-url-CCI-host.  Thanks Greg Marr <gregm@WPI.EDU>.

;; 0.30 23 Mar 1996
;;	Contact/start Netscape in the background.
;;	Thanks Per Abrahamsen <abraham@dina.kvl.dk>

;; 0.31 28 Apr 1996
;;	Added browse-url command.
;;	Added new-window logic to b-u-interactive-arg.
;;	b-u-file-url checks for EFS path.

;; 0.32 02 May 1996
;;	Improved b-u-url-at-point matching to supply missing "http://".

;; 0.33 01 Jun 1996
;;	Jari Aalto <jaalto@tre.tele.nokia.fi> browse-url-lynx-emacs
;;	fix.  Thanks Jari.

;; 0.34 05 Jun 1996
;;	b-u-file-url checks for EFS after alist.  Thanks
;;	Jens-U H Petersen <petersen@kurims.kyoto-u.ac.jp>

;; 0.35 11 Jun 1996
;;	Grail support.  Thanks Barry A. Warsaw
;;	<bwarsaw@anthem.cnri.reston.va.us>.

;; 0.36 12 Jun 1996
;;	Fixed browse-url-looking-at (I hope).

;; 0.37 15 Jun 1996
;;	b-u-file-url URL-encodes special chars.
;;	Thanks Martin Schwenke <Martin.Schwenke@cs.anu.edu.au>.

;; 0.38 17 Jun 1996
;;	b-u-file-url encodes fewer chars.  Multi-display support for
;;	Netscape.  Thanks Richard Mlynarik <mly@adoc.xerox.com>

;;; Code:

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Variables

(eval-when-compile (require 'dired))

(defvar browse-url-path-regexp
  "[^]\t\n \"'()<>[^`{}]*[^]\t\n \"'()<>[^`{}.,;]+"
  "A regular expression probably matching the host, path or e-mail
part of a URL.")

(defvar browse-url-short-regexp
  (concat "[-A-Za-z0-9.]+" browse-url-path-regexp)
  "A regular expression probably matching a URL without an access scheme.
Hostname matching is stricter in this case than for
``browse-url-regexp''.")

(defvar browse-url-regexp
  (concat
   "\\(https?://\\|ftp://\\|gopher://\\|telnet://\\|wais://\\|file:/\\|s?news:\\|mailto:\\)"
   browse-url-path-regexp)
  "A regular expression probably matching a complete URL.")


;;;###autoload
(defvar browse-url-browser-function 'browse-url-w3
  "*Function to display the current buffer in a WWW browser.
Used by the `browse-url-at-point', `browse-url-at-mouse', and
`browse-url-of-file' commands.")

(defvar browse-url-netscape-command "netscape"
  "*The name by which to invoke Netscape.")

(defvar browse-url-netscape-arguments nil
  "*A list of strings to pass to Netscape as arguments.")

(defvar browse-url-new-window-p nil
  "*If non-nil, always open a new browser window.
Passing an interactive argument to \\[browse-url-netscape] or
\\[browse-url-cci] reverses the effect of this variable.  Requires
Netscape version 1.1N or later or XMosaic version 2.5 or later.")

(defvar browse-url-mosaic-arguments nil
  "*A list of strings to pass to Mosaic as arguments.")

(defvar browse-url-filename-alist
  '(("^/+" . "file:/"))
  "An alist of (REGEXP . STRING) pairs.
Any substring of a filename matching one of the REGEXPs is replaced by
the corresponding STRING.  All pairs are applied in the order given.
The default value prepends `file:' to any path beginning with `/'.
Used by the `browse-url-of-file' command.")

(defvar browse-url-save-file nil
  "If non-nil, save the buffer before displaying its file.
Used by the `browse-url-of-file' command.")

(defvar browse-url-of-file-hook nil
  "A hook to be run with run-hook after `browse-url-of-file' has asked
a browser to load a file.

Set this to `browse-url-netscape-reload' to force Netscape to load the
file rather than displaying a cached copy.")

(defvar browse-url-usr1-signal
  (if (and (boundp 'emacs-major-version)
	   (or (> emacs-major-version 19) (>= emacs-minor-version 29)))
      'SIGUSR1 ; Why did I think this was in lower case before?
    30)					; Check /usr/include/signal.h.
  "The argument to `signal-process' for sending SIGUSR1 to XMosaic.
Emacs 19.29 accepts 'SIGUSR1, earlier versions require an integer
which is 30 on SunOS and 16 on HP-UX and Solaris.")

(defvar browse-url-CCI-port 3003
  "Port to access XMosaic via CCI.
This can be any number between 1024 and 65535 but must correspond to
the value set in the browser.")

(defvar browse-url-CCI-host "localhost"
  "*Host to access XMosaic via CCI.
This should be the host name of the machine running XMosaic with CCI
enabled.  The port number should be set in `browse-url-CCI-port'.")

(defvar browse-url-temp-file-name nil)
(make-variable-buffer-local 'browse-url-temp-file-name)

(defvar browse-url-temp-file-list '())

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; URL input

;; thingatpt.el doesn't work for complex regexps

(defun browse-url-url-at-point ()
  "Return the URL around or before point.
Search backwards for the start of a URL ending at or after 
point.  If no URL found, return the empty string.  The
access scheme, `http://' will be prepended if absent."
  (cond ((browse-url-looking-at browse-url-regexp)
	 (buffer-substring (match-beginning 0) (match-end 0)))
	;; Access scheme omitted?
	((browse-url-looking-at browse-url-short-regexp)
	 (concat "http://"
		 (buffer-substring (match-beginning 0) (match-end 0))))
	(t "")))			; No match

(defun browse-url-looking-at (regexp)
  "Return non-nil if point is in or just after a match for REGEXP.
Set the match data from the earliest such match in the current line
ending at or after point."
  (save-excursion
    (let ((old-point (point))
	  (eol (progn (end-of-line) (point)))
	  (hit nil))
      (beginning-of-line)
      (or (and (looking-at regexp)
	       (>= (match-end 0) old-point))
	  (progn
	    (while (and (re-search-forward regexp eol t)
			(<= (match-beginning 0) old-point)
			(not (setq hit (>= (match-end 0) old-point)))))
	    hit)))))

;; Having this as a separate function called by the browser-specific
;; functions allows them to be stand-alone commands, making it easier
;; to switch between browsers.

(defun browse-url-interactive-arg (prompt)
  "Read a URL from the minibuffer, prompting with PROMPT.
Default to the URL at or before point.  If invoke with a mouse button,
set point to the position clicked first.  Return a list for use in
`interactive' containing the URL and browse-url-new-window-p or its
negation if a prefix argument was given."
  (let ((event (elt (this-command-keys) 0)))
    (and (listp event) (mouse-set-point event)))
  (list (read-string prompt (browse-url-url-at-point))
	(not (eq (null browse-url-new-window-p)
		 (null current-prefix-arg)))))

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Browse current buffer

(defun browse-url-of-file (&optional file)
  "Ask a WWW browser to display FILE.
Display the current buffer's file if FILE is nil or if called
interactively.  Turn the filename into a URL with function
browse-url-file-url.  Pass the URL to a browser using variable
`browse-url-browser-function' then run `browse-url-of-file-hook'."
  (interactive)
  (or file
      (setq file (buffer-file-name))
      (error "Current buffer has no file"))
  (let ((buf (get-file-buffer file)))
    (if buf
	(save-excursion
	  (set-buffer buf)
	  (cond ((not (buffer-modified-p)))
		(browse-url-save-file (save-buffer))
		(t (message "%s modified since last save" file))))))
  (funcall browse-url-browser-function (browse-url-file-url file))
  (run-hooks 'browse-url-of-file-hook))

(defun browse-url-file-url (file)
  "Return the URL corresponding to FILE.
Use variable `browse-url-filename-alist' to map filenames to URLs.
Convert EFS file names of the form /USER@HOST:PATH to ftp://HOST/PATH."
  ;; URL-encode special chars, do % first
  (let ((s 0))
    (while (setq s (string-match "%" file s))
      (setq file (replace-match "%25" t t file)
	    s (1+ s))))
  (while (string-match "[*\"()',=;? ]" file)
    (setq enc (format "%%%x" (aref file (match-beginning 0)))
	  file (replace-match enc t t file)))
  (let ((maps browse-url-filename-alist))
    (while maps
      (let* ((map (car maps))
	     (from-re (car map))
	     (to-string (cdr map)))
	(setq maps (cdr maps))
	(and (string-match from-re file)
	     (setq file (replace-match to-string t t file))))))
  ;; Check for EFS path
  (and (string-match "^/\\([^:@]+@\\)?\\([^:]+\\):/*" file)
       (setq file (concat "ftp://"
			  (substring file (match-beginning 2) (match-end 2))
			  "/" (substring file (match-end 0)))))
  file)

(defun browse-url-of-buffer (&optional buffer)
  "Ask a WWW browser to display BUFFER.
Display the current buffer if BUFFER is nil."
  (interactive)
  (save-excursion
    (and buffer (set-buffer buffer))
    (let ((file-name
	   (or buffer-file-name
	       (and (boundp 'dired-directory) dired-directory))))
      (or file-name
	  (progn
	    (or browse-url-temp-file-name
		(setq browse-url-temp-file-name
		      (make-temp-name
		       (expand-file-name (buffer-name)
					 (or (getenv "TMPDIR") "/tmp")))
		      browse-url-temp-file-list
		      (cons browse-url-temp-file-name
			    browse-url-temp-file-list)))
	    (setq file-name browse-url-temp-file-name)
	    (write-region (point-min) (point-max) file-name nil 'no-message)))
      (browse-url-of-file file-name))))

(defun browse-url-delete-temp-file (&optional temp-file-name)
  ;; Delete browse-url-temp-file-name from the file system and from
  ;; browse-url-temp-file-list.  If optional arg TEMP-FILE-NAME is
  ;; non-nil, delete it instead, but only from the file system --
  ;; browse-url-temp-file-list is not affected.
  (let ((file-name (or temp-file-name browse-url-temp-file-name)))
    (if (and file-name (file-exists-p file-name))
	(progn
	  (delete-file file-name)
	  (if (null temp-file-name)
	      (setq browse-url-temp-file-list
		    (delete browse-url-temp-file-name
			    browse-url-temp-file-list)))))))

(defun browse-url-delete-temp-file-list ()
  ;; Delete all elements of browse-url-temp-file-list.
  (while browse-url-temp-file-list
    (browse-url-delete-temp-file (car browse-url-temp-file-list))
    (setq browse-url-temp-file-list
	  (cdr browse-url-temp-file-list))))

(add-hook 'kill-buffer-hook 'browse-url-delete-temp-file)
(add-hook 'kill-emacs-hook 'browse-url-delete-temp-file-list)

(defun browse-url-of-dired-file ()
  "In Dired, ask a WWW browser to display the file named on this line."
  (interactive)
  (browse-url-of-file (dired-get-filename)))

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Browser-independant commands

;; A generic command to call the current b-u-browser-function

(defun browse-url (&rest args)
  "Ask a WWW browser to load URL.
Prompts for a URL, defaulting to the URL at or before point.  Variable
`browse-url-browser-function' says which browser to use."
  (interactive (browse-url-interactive-arg "URL: "))
  (apply browse-url-browser-function args))

(defun browse-url-at-point ()
  "Ask a WWW browser to load the URL at or before point.
Doesn't let you edit the URL like browse-url.  Variable
`browse-url-browser-function' says which browser to use."
  (interactive)
  (funcall browse-url-browser-function (browse-url-url-at-point)))

;; Define these if not already defined (XEmacs compatibility)

(eval-and-compile
  (or (fboundp 'event-buffer)
      (defun event-buffer (event)
	(window-buffer (posn-window (event-start event))))))

(eval-and-compile
  (or (fboundp 'event-point)
      (defun event-point (event)
	(posn-point (event-start event)))))

(defun browse-url-at-mouse (event)
  "Ask a WWW browser to load a URL clicked with the mouse.
The URL is the one around or before the position of the mouse click
but point is not changed.  Doesn't let you edit the URL like
browse-url.  Variable `browse-url-browser-function' says which browser
to use."
  (interactive "e")
  (save-excursion
    (set-buffer (event-buffer event))
    (goto-char (event-point event))
    (let ((url (browse-url-url-at-point)))
      (if (string-equal url "")
	  (error "No URL found"))
      (funcall browse-url-browser-function url))))

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Browser-specific commands

;; --- Netscape ---

;; Put the correct DISPLAY value in the environment for Netscape
;; launched from multi-display Emacs.

(defun browse-url-process-environment ()
  (let* ((device (and (fboundp 'selected-device)
		      (fboundp 'device-connection)
                      (selected-device)))
         (display (and device (fboundp 'device-type)
                       (eq (device-type device) 'x)
                       (not (equal (device-connection device)
                                   (getenv "DISPLAY"))))))
    (if display
        ;; Attempt to run on the correct display
        (cons (concat "DISPLAY=" (device-connection device))
              process-environment)
      process-environment)))


;;;###autoload
(defun browse-url-netscape (url &optional new-window)
  "Ask the Netscape WWW browser to load URL.

Default to the URL around or before point.  The strings in variable
`browse-url-netscape-arguments' are also passed to Netscape.

When called interactively, if variable `browse-url-new-window-p' is
non-nil, load the document in a new Netscape window, otherwise use a
random existing one.  A non-nil interactive prefix argument reverses
the effect of browse-url-new-window-p.

When called non-interactively, optional second argument NEW-WINDOW is
used instead of browse-url-new-window-p."
  (interactive (browse-url-interactive-arg "Netscape URL: "))
  (let* ((process-environment (browse-url-process-environment))
         (process (apply 'start-process
 			(concat "netscape " url) nil
 			browse-url-netscape-command
 			(append browse-url-netscape-arguments
 				(if new-window '("-noraise"))
 				(list "-remote" 
 				      (concat "openURL(" url 
 					      (if new-window ",new-window")
 					      ")"))))))
    (set-process-sentinel process
       (list 'lambda '(process change)
	     (list 'browse-url-netscape-sentinel 'process url)))))

(defun browse-url-netscape-sentinel (process url)
  "Handle a change to the process communicating with Netscape."
  (or (eq (process-exit-status process) 0)
      (let* ((process-environment (browse-url-process-environment)))
	;; Netscape not running - start it
	(message "Starting Netscape...")
	(apply 'start-process (concat "netscape" url) nil
	       browse-url-netscape-command
	       (append browse-url-netscape-arguments (list url))))))

(defun browse-url-netscape-reload ()
  "Ask Netscape to reload its current document."
  (interactive)
  (browse-url-netscape-send "reload"))

(defun browse-url-netscape-send (command)
  "Send a remote control command to Netscape."
  (let* ((process-environment (browse-url-process-environment)))
    (apply 'start-process "netscape" nil
           browse-url-netscape-command
           (append browse-url-netscape-arguments
                   (list "-remote" command)))))

;; --- Mosaic ---

;;;###autoload
(defun browse-url-mosaic (url &optional new-window)
  ;; new-window ignored
  "Ask the XMosaic WWW browser to load URL.
Default to the URL around or before point."
  (interactive (browse-url-interactive-arg "Mosaic URL: "))
  (let ((pidfile (expand-file-name "~/.mosaicpid"))
	pid pidbuf)
    (if (file-readable-p pidfile)
	(save-excursion
	  (find-file pidfile)
	  (goto-char (point-min))
	  (setq pid (read (current-buffer)))
	  (kill-buffer nil)))
    (if (and pid (zerop (signal-process pid 0))) ; Mosaic running
	(save-excursion
	  (find-file (format "/tmp/Mosaic.%d" pid))
	  (erase-buffer)
	  (insert "goto\n" url "\n")
	  (save-buffer)
	  (kill-buffer nil)
	  ;; Send signal SIGUSR to Mosaic
	  (message "Signalling Mosaic...")
	  (signal-process pid browse-url-usr1-signal)
	  ;; Or you could try:
	  ;; (call-process "kill" nil 0 nil "-USR1" (int-to-string pid))
	  (message "Signalling Mosaic...done")
	  )
      ;; Mosaic not running - start it
      (message "Starting Mosaic...")
      (apply 'start-process "xmosaic" nil "xmosaic"
	     (append browse-url-mosaic-arguments (list url)))
      (message "Starting Mosaic...done"))))

;; --- Grail ---

(defvar browse-url-grail
  (concat (or (getenv "GRAILDIR") "~/.grail") "/user/rcgrail.py")
  "*Location of Grail remote control client script `rcgrail.py'.
Typically found in $GRAILDIR/rcgrail.py, or ~/.grail/user/rcgrail.py.")

;;;###autoload
(defun browse-url-grail (url)
  "Ask the Grail WWW browser to load URL.
Default to the URL around or before point.  Runs the program in the
variable `browse-url-grail'."
  (interactive (browse-url-interactive-arg "Grail URL: "))
  (message "Sending URL to Grail...")
  (save-excursion
    (set-buffer (get-buffer-create " *Shell Command Output*"))
    (erase-buffer)
    ;; don't worry about this failing.
    (call-process browse-url-grail nil 0 nil url)
    (message "Sending URL to Grail... done")))

;; --- Mosaic using CCI ---

(defun browse-url-cci (url &optional new-window)
  "Ask the XMosaic WWW browser to load URL.
Default to the URL around or before point.

This function only works for XMosaic version 2.5 or later.  You must
select `CCI' from XMosaic's File menu, set the CCI Port Address to the
value of variable `browse-url-CCI-port', and enable `Accept requests'.

When called interactively, if variable `browse-url-new-window-p' is
non-nil, load the document in a new browser window, otherwise use a
random existing one.  A non-nil interactive prefix argument reverses
the effect of browse-url-new-window-p.

When called non-interactively, optional second argument NEW-WINDOW is
used instead of browse-url-new-window-p."
  (interactive (browse-url-interactive-arg "Mosaic URL: "))
  (open-network-stream "browse-url" " *browse-url*"
		       browse-url-CCI-host browse-url-CCI-port)
  ;; Todo: start browser if fails
  (process-send-string "browse-url"
		       (concat "get url (" url ") output "
			       (if new-window "new" "current") "\r\n"))
  (process-send-string "browse-url" "disconnect\r\n")
  (delete-process "browse-url"))

;; --- IXI Mosaic ---

;;;###autoload
(defun browse-url-iximosaic (url &optional new-window)
  ;; new-window ignored
  "Ask the IXIMosaic WWW browser to load URL.
Default to the URL around or before point."
  (interactive (browse-url-interactive-arg "IXI Mosaic URL: "))
  (start-process "tellw3b" nil "tellw3b"
		 "-service WWW_BROWSER ixi_showurl " url))

;; --- W3 ---

;;;###autoload
(defun browse-url-w3 (url &optional new-window)
  ;; new-window ignored
  "Ask the w3 WWW browser to load URL.
Default to the URL around or before point."
  (interactive (browse-url-interactive-arg "W3 URL: "))
  (w3-fetch url))

;; --- Lynx in an xterm ---

;;;###autoload
(defun browse-url-lynx-xterm (url &optional new-window)
  ;; new-window ignored
  "Ask the Lynx WWW browser to load URL.
Default to the URL around or before point.  A new Lynx process is run
in an Xterm window."
  (interactive (browse-url-interactive-arg "Lynx URL: "))
  (start-process (concat "lynx" url) nil "xterm" "-e" "lynx" url))

(eval-when-compile (require 'term))

;; --- Lynx in an Emacs "term" window ---

;;;###autoload
(defun browse-url-lynx-emacs (url &optional new-window)
  ;; new-window ignored
  "Ask the Lynx WWW browser to load URL.
Default to the URL around or before point.  Run a new Lynx process in
an Emacs buffer."
  (interactive (browse-url-interactive-arg "Lynx URL: "))
  (let ((system-uses-terminfo t))	; Lynx uses terminfo
    (if (fboundp 'make-term)
	(let ((term-term-name "vt100"))
	  (set-buffer (make-term "browse-url" "lynx" nil url))
	  (term-mode)
	  (term-char-mode)
	  (switch-to-buffer "*browse-url*"))
      (terminal-emulator "*browse-url*" "lynx" (list url)))))

(provide 'browse-url)

;;; browse-url.el ends here
