;;; process.el --- commands for subprocesses; split out of simple.el

;; Copyright (C) 1985-7, 1993,4, 1997 Free Software Foundation, Inc.
;; Copyright (C) 1995, 2000, 2001 Ben Wing.

;; Author: Ben Wing
;; Maintainer: XEmacs Development Team
;; Keywords: internal, processes, dumped

;; 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, 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.

;;; Synched up with: FSF 19.30, except for setenv/getenv (synched with FSF
;;; 21.0.105).

;;; Authorship:

;; Created 1995 by Ben Wing during Mule work -- some commands split out
;; of simple.el and wrappers of *-internal functions created so they could
;; be redefined in a Mule world.
;; Lisp definition of call-process-internal added Mar. 2000 by Ben Wing.

;;; Commentary:

;; This file is dumped with XEmacs.

;;; Code:


(defgroup processes nil
  "Process, subshell, compilation, and job control support."
  :group 'external
  :group 'development)

(defgroup processes-basics nil
  "Basic stuff dealing with processes."
  :group 'processes)

(defgroup execute nil
  "Executing external commands."
  :group 'processes)

;; This may be changed to "/c" in win32-native.el.

(defvar shell-command-switch "-c"
  "Switch used to have the shell execute its command line argument.")

(defun start-process-shell-command (name buffer &rest args)
  "Start a program in a subprocess.  Return the process object for it.
Args are NAME BUFFER COMMAND &rest COMMAND-ARGS.
NAME is name for process.  It is modified if necessary to make it unique.
BUFFER is the buffer or (buffer-name) to associate with the process.
 Process output goes at end of that buffer, unless you specify
 an output stream or filter function to handle the output.
 BUFFER may be also nil, meaning that this process is not associated
 with any buffer
Third arg is command name, the name of a shell command.
Remaining arguments are the arguments for the command.
Wildcards and redirection are handled as usual in the shell."
  ;; We used to use `exec' to replace the shell with the command,
  ;; but that failed to handle (...) and semicolon, etc.
  (start-process name buffer shell-file-name shell-command-switch
		 (mapconcat #'identity args " ")))

(defun call-process-internal (program &optional infile buffer display &rest args)
  "Call PROGRAM synchronously in separate process, with coding-system specified.
Arguments are
 (PROGRAM &optional INFILE BUFFER DISPLAY &rest ARGS).
The program's input comes from file INFILE (nil means `/dev/null').
Insert output in BUFFER before point; t means current buffer;
 nil for BUFFER means discard it; 0 means discard and don't wait.
BUFFER can also have the form (REAL-BUFFER STDERR-FILE); in that case,
REAL-BUFFER says what to do with standard output, as above,
while STDERR-FILE says what to do with standard error in the child.
STDERR-FILE may be nil (discard standard error output),
t (mix it with ordinary output), or a file name string.

Fourth arg DISPLAY non-nil means redisplay buffer as output is inserted.
Remaining arguments are strings passed as command arguments to PROGRAM.

If BUFFER is 0, `call-process' returns immediately with value nil.
Otherwise it waits for PROGRAM to terminate and returns a numeric exit status
 or a signal description string.
If you quit, the process is killed with SIGINT, or SIGKILL if you
 quit again."
  ;; #### remove windows-nt check when this is ready for prime time.
  (if (not (eq 'windows-nt system-type))
      (apply 'old-call-process-internal program infile buffer display args)
    (let (proc inbuf errbuf discard)
      (unwind-protect
	  (progn
	    (when infile
	      (setq infile (expand-file-name infile))
	      (setq inbuf (generate-new-buffer "*call-process*"))
	      (with-current-buffer inbuf
               ;; Make sure this works with jka-compr
               (let ((file-name-handler-alist nil))
                 (insert-file-contents-internal infile nil nil nil nil
                                                'binary))))
	    (let ((stderr (if (consp buffer) (second buffer) t)))
	      (if (consp buffer) (setq buffer (car buffer)))
	      (setq buffer
		    (cond ((null buffer) nil)
			  ((eq buffer t) (current-buffer))
			  ;; use integerp for compatibility with existing
			  ;; call-process rmsism.
			  ((integerp buffer) (setq discard t) nil)
			  (t (get-buffer-create buffer))))
	      (when (and stderr (not (eq t stderr)))
		(setq stderr (expand-file-name stderr))
		(setq errbuf (generate-new-buffer "*call-process*")))
	      (setq proc
		    (apply 'start-process-internal "*call-process*"
			   buffer
			   ;#### not implemented until my new process
			   ;changes go in.
			   ;(if (eq t stderr) buffer (list buffer errbuf))
			   program args))
	      (if buffer
		  (set-marker (process-mark proc) (point buffer) buffer))
	      (unwind-protect
		  (prog1
		    (catch 'call-process-done
		      (when (not discard)
			(set-process-sentinel
			 proc
			 #'(lambda (proc status)
			     (cond ((eq 'exit (process-status proc))
				    (set-process-sentinel proc nil)
				    (throw 'call-process-done
					   (process-exit-status proc)))
				   ((eq 'signal (process-status proc))
				    (set-process-sentinel proc nil)
				    (throw 'call-process-done status))))))
		      (when inbuf
			(process-send-region proc 1
					     (1+ (buffer-size inbuf)) inbuf))
		      (process-send-eof proc)
		      (when discard
			;; we're trying really really hard to emulate
			;; the old call-process.
			(if errbuf
			    (set-process-sentinel
			     proc
			     `(lambda (proc status)
				(write-region-internal
				 1 (1+ (buffer-size))
				 ,stderr
				 nil 'major-rms-kludge-city nil
				 coding-system-for-write))))
			(setq errbuf nil)
			(setq proc nil)
			(throw 'call-process-done nil))
		      (while t
			(accept-process-output proc)
			(if display (sit-for 0))))
		    (when errbuf
		      (with-current-buffer errbuf
			(write-region-internal 1 (1+ (buffer-size)) stderr
					       nil 'major-rms-kludge-city nil
					       coding-system-for-write))))
		(if proc (set-process-sentinel proc nil)))))
	(if inbuf (kill-buffer inbuf))
	(if errbuf (kill-buffer errbuf))
	(condition-case nil
	    (if (and proc (process-live-p proc)) (kill-process proc))
	  (error nil))))))

(defun call-process (program &optional infile buffer displayp &rest args)
  "Call PROGRAM synchronously in separate process.
The program's input comes from file INFILE (nil means `/dev/null').
Insert output in BUFFER before point; t means current buffer;
 nil for BUFFER means discard it; 0 means discard and don't wait.
BUFFER can also have the form (REAL-BUFFER STDERR-FILE); in that case,
REAL-BUFFER says what to do with standard output, as above,
while STDERR-FILE says what to do with standard error in the child.
STDERR-FILE may be nil (discard standard error output),
t (mix it with ordinary output), or a file name string.

Fourth arg DISPLAYP non-nil means redisplay buffer as output is inserted.
Remaining arguments are strings passed as command arguments to PROGRAM.

If BUFFER is 0, `call-process' returns immediately with value nil.
Otherwise it waits for PROGRAM to terminate and returns a numeric exit status
 or a signal description string.
If you quit, the process is killed with SIGINT, or SIGKILL if you
 quit again."
  (apply 'call-process-internal program infile buffer displayp args))

(defun call-process-region (start end program
                            &optional deletep buffer displayp
                            &rest args)
  "Send text from START to END to a synchronous process running PROGRAM.
Delete the text if fourth arg DELETEP is non-nil.

Insert output in BUFFER before point; t means current buffer;
 nil for BUFFER means discard it; 0 means discard and don't wait.
BUFFER can also have the form (REAL-BUFFER STDERR-FILE); in that case,
REAL-BUFFER says what to do with standard output, as above,
while STDERR-FILE says what to do with standard error in the child.
STDERR-FILE may be nil (discard standard error output),
t (mix it with ordinary output), or a file name string.

Sixth arg DISPLAYP non-nil means redisplay buffer as output is inserted.
Remaining args are passed to PROGRAM at startup as command args.

If BUFFER is 0, returns immediately with value nil.
Otherwise waits for PROGRAM to terminate
and returns a numeric exit status or a signal description string.
If you quit, the process is first killed with SIGINT, then with SIGKILL if
you quit again before the process exits."
  (let ((temp
	 (make-temp-name
	  (concat (file-name-as-directory (temp-directory)) "emacs"))))
    (unwind-protect
	(progn
	  (write-region start end temp nil 'silent)
	  (if deletep (delete-region start end))
	  (apply #'call-process program temp buffer displayp args))
      (ignore-file-errors (delete-file temp)))))


(defun shell-command (command &optional output-buffer)
  "Execute string COMMAND in inferior shell; display output, if any.

If COMMAND ends in ampersand, execute it asynchronously.
The output appears in the buffer `*Async Shell Command*'.
That buffer is in shell mode.

Otherwise, COMMAND is executed synchronously.  The output appears in the
buffer `*Shell Command Output*'.
If the output is one line, it is displayed in the echo area *as well*,
but it is nonetheless available in buffer `*Shell Command Output*',
even though that buffer is not automatically displayed.
If there is no output, or if output is inserted in the current buffer,
then `*Shell Command Output*' is deleted.

The optional second argument OUTPUT-BUFFER, if non-nil,
says to put the output in some other buffer.
If OUTPUT-BUFFER is a buffer or buffer name, put the output there.
If OUTPUT-BUFFER is not a buffer and not nil,
insert output in current buffer.  (This cannot be done asynchronously.)
In either case, the output is inserted after point (leaving mark after it)."
  (interactive (list (read-shell-command "Shell command: ")
		     current-prefix-arg))
  (if (and output-buffer
	   (not (or (bufferp output-buffer)  (stringp output-buffer))))
      (progn (barf-if-buffer-read-only)
	     (push-mark nil (not (interactive-p)))
	     ;; We do not use -f for csh; we will not support broken use of
	     ;; .cshrcs.  Even the BSD csh manual says to use
	     ;; "if ($?prompt) exit" before things which are not useful
	     ;; non-interactively.  Besides, if someone wants their other
	     ;; aliases for shell commands then they can still have them.
	     (call-process shell-file-name nil t nil
			   shell-command-switch command)
	     (exchange-point-and-mark t))
    ;; Preserve the match data in case called from a program.
    (save-match-data
      (if (string-match "[ \t]*&[ \t]*$" command)
	  ;; Command ending with ampersand means asynchronous.
	  (progn
	    (if-fboundp 'background
		(background (substring command 0
				       (match-beginning 0)))
	      (error
	       'unimplemented
	       "backgrounding a shell command requires package `background'")))
	    
	(shell-command-on-region (point) (point) command output-buffer)))))

;; We have a sentinel to prevent insertion of a termination message
;; in the buffer itself.
(defun shell-command-sentinel (process signal)
  (if (memq (process-status process) '(exit signal))
      (message "%s: %s."
	       (car (cdr (cdr (process-command process))))
	       (substring signal 0 -1))))

(defun shell-command-on-region (start end command
				      &optional output-buffer replace)
  "Execute string COMMAND in inferior shell with region as input.
Normally display output (if any) in temp buffer `*Shell Command Output*';
Prefix arg means replace the region with it.

The noninteractive arguments are START, END, COMMAND, OUTPUT-BUFFER, REPLACE.
If REPLACE is non-nil, that means insert the output
in place of text from START to END, putting point and mark around it.

If the output is one line, it is displayed in the echo area,
but it is nonetheless available in buffer `*Shell Command Output*'
even though that buffer is not automatically displayed.
If there is no output, or if output is inserted in the current buffer,
then `*Shell Command Output*' is deleted.

If the optional fourth argument OUTPUT-BUFFER is non-nil,
that says to put the output in some other buffer.
If OUTPUT-BUFFER is a buffer or buffer name, put the output there.
If OUTPUT-BUFFER is not a buffer and not nil,
insert output in the current buffer.
In either case, the output is inserted after point (leaving mark after it)."
  (interactive (let ((string
		      ;; Do this before calling region-beginning
		      ;; and region-end, in case subprocess output
		      ;; relocates them while we are in the minibuffer.
		      (read-shell-command "Shell command on region: ")))
		 ;; call-interactively recognizes region-beginning and
		 ;; region-end specially, leaving them in the history.
		 (list (region-beginning) (region-end)
		       string
		       current-prefix-arg
		       current-prefix-arg)))
  (if (or replace
	  (and output-buffer
	       (not (or (bufferp output-buffer) (stringp output-buffer)))))
      ;; Replace specified region with output from command.
      (let ((swap (and replace (< start end))))
	;; Don't muck with mark unless REPLACE says we should.
	(goto-char start)
	(and replace (push-mark))
	(call-process-region start end shell-file-name t t nil
			     shell-command-switch command)
	(let ((shell-buffer (get-buffer "*Shell Command Output*")))
	  (and shell-buffer (not (eq shell-buffer (current-buffer)))
	       (kill-buffer shell-buffer)))
	;; Don't muck with mark unless REPLACE says we should.
	(and replace swap (exchange-point-and-mark t)))
      ;; No prefix argument: put the output in a temp buffer,
      ;; replacing its entire contents.
    (let ((buffer (get-buffer-create
		   (or output-buffer "*Shell Command Output*")))
	  (success nil)
	  (exit-status nil)
	  (directory default-directory))
      (unwind-protect
	  (if (eq buffer (current-buffer))
	      ;; If the input is the same buffer as the output,
	      ;; delete everything but the specified region,
	      ;; then replace that region with the output.
	      (progn (setq buffer-read-only nil)
		     (delete-region (max start end) (point-max))
		     (delete-region (point-min) (max start end))
		     (setq exit-status
			   (call-process-region (point-min) (point-max)
						shell-file-name t t nil
						shell-command-switch command))
		     (setq success t))
	    ;; Clear the output buffer,
	    ;; then run the command with output there.
	    (save-excursion
	      (set-buffer buffer)
	      (setq buffer-read-only nil)
	      ;; XEmacs change
	      (setq default-directory directory)
	      (erase-buffer))
	    (setq exit-status
		  (call-process-region start end shell-file-name
				       nil buffer nil
				       shell-command-switch command))
	    (setq success t))
	;; Report the amount of output.
	(let ((lines (save-excursion
		       (set-buffer buffer)
		       (if (= (buffer-size) 0)
			   0
			 (count-lines (point-min) (point-max))))))
	  (cond ((= lines 0)
		 (if success
		     (display-message
		      'command
		      (if (eql exit-status 0)
			  "(Shell command succeeded with no output)"
			"(Shell command failed with no output)")))
		 (kill-buffer buffer))
		((and success (= lines 1))
		 (message "%s"
			  (save-excursion
			    (set-buffer buffer)
			    (goto-char (point-min))
			    (buffer-substring (point)
					      (progn (end-of-line)
						     (point))))))
		(t
		 (set-window-start (display-buffer buffer) 1))))))))


(defun start-process (name buffer program &rest program-args)
  "Start a program in a subprocess.  Return the process object for it.
Args are NAME BUFFER PROGRAM &rest PROGRAM-ARGS
NAME is name for process.  It is modified if necessary to make it unique.
BUFFER is the buffer or (buffer-name) to associate with the process.
 Process output goes at end of that buffer, unless you specify
 an output stream or filter function to handle the output.
 BUFFER may be also nil, meaning that this process is not associated
 with any buffer
Third arg is program file name.  It is searched for as in the shell.
Remaining arguments are strings to give program as arguments."
  (apply 'start-process-internal name buffer program program-args))

(defun open-network-stream (name buffer host service &optional protocol)
  "Open a TCP connection for a service to a host.
Returns a process object to represent the connection.
Input and output work as for subprocesses; `delete-process' closes it.
Args are NAME BUFFER HOST SERVICE.
NAME is name for process.  It is modified if necessary to make it unique.
BUFFER is the buffer (or buffer-name) to associate with the process.
 Process output goes at end of that buffer, unless you specify
 an output stream or filter function to handle the output.
 BUFFER may be also nil, meaning that this process is not associated
 with any buffer
Third arg is name of the host to connect to, or its IP address.
Fourth arg SERVICE is name of the service desired, or an integer
 specifying a port number to connect to.
Fifth argument PROTOCOL is a network protocol.  Currently 'tcp
 (Transmission Control Protocol) and 'udp (User Datagram Protocol) are
 supported.  When omitted, 'tcp is assumed.

Output via `process-send-string' and input via buffer or filter (see
`set-process-filter') are stream-oriented.  That means UDP datagrams are
not guaranteed to be sent and received in discrete packets. (But small
datagrams around 500 bytes that are not truncated by `process-send-string'
are usually fine.)  Note further that UDP protocol does not guard against
lost packets."
  (open-network-stream-internal name buffer host service protocol))

(defun shell-quote-argument (argument)
  "Quote an argument for passing as argument to an inferior shell."
  (if (and (eq system-type 'windows-nt)
	   (let ((progname (downcase (file-name-nondirectory
				      shell-file-name))))
	     (or (equal progname "command.com")
		 (equal progname "cmd.exe"))))
      ;; the expectation is that you can take the result of
      ;; shell-quote-argument and pass it to as an arg to
      ;; (start-process shell-quote-argument ...) and have it end
      ;; up as-is in the program's argv[] array.  to do this, we
      ;; need to protect against both the shell's and the program's
      ;; quoting conventions (and our own conventions in
      ;; mswindows-construct-process-command-line!).  Putting quotes
      ;; around shell metachars gets through the last two, and applying
      ;; the normal VC runtime quoting works with practically all apps.
      (declare-fboundp (mswindows-quote-one-vc-runtime-arg argument t))
    (if (equal argument "")
	"\"\""
      ;; Quote everything except POSIX filename characters.
      ;; This should be safe enough even for really weird shells.
      (let ((result "") (start 0) end)
	(while (string-match "[^-0-9a-zA-Z_./]" argument start)
	  (setq end (match-beginning 0)
		result (concat result (substring argument start end)
			       "\\" (substring argument end (1+ end)))
		start (1+ end)))
	(concat result (substring argument start))))))

(defun shell-command-to-string (command)
  "Execute shell command COMMAND and return its output as a string."
  (with-output-to-string
    (call-process shell-file-name nil t nil shell-command-switch command)))

(defalias 'exec-to-string 'shell-command-to-string)


;; History list for environment variable names.
(defvar read-envvar-name-history nil)

(defun read-envvar-name (prompt &optional mustmatch)
  "Read environment variable name, prompting with PROMPT.
Optional second arg MUSTMATCH, if non-nil, means require existing envvar name.
If it is also not t, RET does not exit if it does non-null completion."
  (completing-read prompt
		   (mapcar (function
			    (lambda (enventry)
			      (list (substring enventry 0
					       (string-match "=" enventry)))))
			   process-environment)
		   nil mustmatch nil 'read-envvar-name-history))

;; History list for VALUE argument to setenv.
(defvar setenv-history nil)

(defun setenv (variable &optional value unset)
  "Set the value of the environment variable named VARIABLE to VALUE.
VARIABLE should be a string.  VALUE is optional; if not provided or is
`nil', the environment variable VARIABLE will be removed.  

Interactively, a prefix argument means to unset the variable.
Interactively, the current value (if any) of the variable
appears at the front of the history list when you type in the new value.

This function works by modifying `process-environment'."
  (interactive
   (if current-prefix-arg
       (list (read-envvar-name "Clear environment variable: " 'exact) nil t)
     (let ((var (read-envvar-name "Set environment variable: " nil)))
       ;; Here finally we specify the args to call setenv with.
       (list var (read-from-minibuffer (format "Set %s to value: " var)
				       nil nil nil 'setenv-history
				       (getenv var))))))
  (if unset (setq value nil))
  (if (string-match "=" variable)
      (error "Environment variable name `%s' contains `='" variable)
    (let ((pattern (concat "\\`" (regexp-quote (concat variable "="))))
	  (case-fold-search nil)
	  (scan process-environment)
	  found)
      (if (string-equal "TZ" variable)
	  (set-time-zone-rule value))
      (while scan
	(cond ((string-match pattern (car scan))
	       (setq found t)
	       (if (eq nil value)
		   (setq process-environment (delq (car scan) process-environment))
		 (setcar scan (concat variable "=" value)))
	       (setq scan nil)))
	(setq scan (cdr scan)))
      (or found
	  (if value
	      (setq process-environment
		    (cons (concat variable "=" value)
			  process-environment)))))))

;; already in C.  Can't move it to Lisp too easily because it's needed
;; extremely early in the Lisp loadup sequence.

; (defun getenv (variable)
;   "Get the value of environment variable VARIABLE.
; VARIABLE should be a string.  Value is nil if VARIABLE is undefined in
; the environment.  Otherwise, value is a string.
;
; This function consults the variable `process-environment'
; for its value."
;   (interactive (list (read-envvar-name "Get environment variable: " t)))
;   (let ((value (getenv-internal variable)))
;     (when (interactive-p)
;       (message "%s" (if value value "Not set")))
;     value))

(provide 'env) ;; Yuck.  Formerly the above were in env.el, which did this
	       ;; provide.

;;; process.el ends here