1;;; esh-ext.el --- commands external to Eshell
2
3;; Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004,
4;;   2005, 2006, 2007 Free Software Foundation, Inc.
5
6;; Author: John Wiegley <johnw@gnu.org>
7
8;; This file is part of GNU Emacs.
9
10;; GNU Emacs is free software; you can redistribute it and/or modify
11;; it under the terms of the GNU General Public License as published by
12;; the Free Software Foundation; either version 2, or (at your option)
13;; any later version.
14
15;; GNU Emacs is distributed in the hope that it will be useful,
16;; but WITHOUT ANY WARRANTY; without even the implied warranty of
17;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18;; GNU General Public License for more details.
19
20;; You should have received a copy of the GNU General Public License
21;; along with GNU Emacs; see the file COPYING.  If not, write to the
22;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
23;; Boston, MA 02110-1301, USA.
24
25(provide 'esh-ext)
26
27(eval-when-compile (require 'esh-maint))
28(require 'esh-util)
29
30(defgroup eshell-ext nil
31  "External commands are invoked when operating system executables are
32loaded into memory, thus beginning a new process."
33  :tag "External commands"
34  :group 'eshell)
35
36;;; Commentary:
37
38;; To force a command to invoked external, either provide an explicit
39;; pathname for the command argument, or prefix the command name with
40;; an asterix character.  Example:
41;;
42;;   grep        ; make invoke `grep' Lisp function, or `eshell/grep'
43;;   /bin/grep   ; will definitely invoke /bin/grep
44;;   *grep        ; will also invoke /bin/grep
45
46;;; User Variables:
47
48(defcustom eshell-ext-load-hook '(eshell-ext-initialize)
49  "*A hook that gets run when `eshell-ext' is loaded."
50  :type 'hook
51  :group 'eshell-ext)
52
53(defcustom eshell-binary-suffixes exec-suffixes
54  "*A list of suffixes used when searching for executable files."
55  :type '(repeat string)
56  :group 'eshell-ext)
57
58(defcustom eshell-force-execution nil
59  "*If non-nil, try to execute binary files regardless of permissions.
60This can be useful on systems like Windows, where the operating system
61doesn't happen to honor the permission bits in certain cases; or in
62cases where you want to associate an interpreter with a particular
63kind of script file, but the language won't let you but a '#!'
64interpreter line in the file, and you don't want to make it executable
65since nothing else but Eshell will be able to understand
66`eshell-interpreter-alist'."
67  :type 'boolean
68  :group 'eshell-ext)
69
70(defun eshell-search-path (name)
71  "Search the environment path for NAME."
72  (if (file-name-absolute-p name)
73      name
74    (let ((list (parse-colon-path (getenv "PATH")))
75	  suffixes n1 n2 file)
76      (while list
77	(setq n1 (concat (car list) name))
78	(setq suffixes eshell-binary-suffixes)
79	(while suffixes
80	  (setq n2 (concat n1 (car suffixes)))
81	  (if (and (or (file-executable-p n2)
82		       (and eshell-force-execution
83			    (file-readable-p n2)))
84		   (not (file-directory-p n2)))
85	      (setq file n2 suffixes nil list nil))
86	  (setq suffixes (cdr suffixes)))
87	(setq list (cdr list)))
88      file)))
89
90(defcustom eshell-windows-shell-file
91  (if (eshell-under-windows-p)
92      (if (string-match "\\(\\`cmdproxy\\|sh\\)\\.\\(com\\|exe\\)"
93			shell-file-name)
94	  (or (eshell-search-path "cmd.exe")
95	      (eshell-search-path "command.com"))
96	shell-file-name))
97  "*The name of the shell command to use for DOS/Windows batch files.
98This defaults to nil on non-Windows systems, where this variable is
99wholly ignored."
100  :type '(choice file (const nil))
101  :group 'eshell-ext)
102
103(defsubst eshell-invoke-batch-file (&rest args)
104  "Invoke a .BAT or .CMD file on DOS/Windows systems."
105  ;; since CMD.EXE can't handle forward slashes in the initial
106  ;; argument...
107  (setcar args (subst-char-in-string ?/ ?\\ (car args)))
108  (throw 'eshell-replace-command
109	 (eshell-parse-command eshell-windows-shell-file (cons "/c" args))))
110
111(defcustom eshell-interpreter-alist
112  (if (eshell-under-windows-p)
113      '(("\\.\\(bat\\|cmd\\)\\'" . eshell-invoke-batch-file)))
114  "*An alist defining interpreter substitutions.
115Each member is a cons cell of the form:
116
117  (MATCH . INTERPRETER)
118
119MATCH should be a regexp, which is matched against the command name,
120or a function.  If either returns a non-nil value, then INTERPRETER
121will be used for that command.
122
123If INTERPRETER is a string, it will be called as the command name,
124with the original command name passed as the first argument, with all
125subsequent arguments following.  If INTERPRETER is a function, it will
126be called with all of those arguments.  Note that interpreter
127functions should throw `eshell-replace-command' with the alternate
128command form, or they should return a value compatible with the
129possible return values of `eshell-external-command', which see."
130  :type '(repeat (cons (choice regexp (function :tag "Predicate"))
131		       (choice string (function :tag "Interpreter"))))
132  :group 'eshell-ext)
133
134(defcustom eshell-alternate-command-hook nil
135  "*A hook run whenever external command lookup fails.
136If a functions wishes to provide an alternate command, they must throw
137it using the tag `eshell-replace-command'.  This is done because the
138substituted command need not be external at all, and therefore must be
139passed up to a higher level for re-evaluation.
140
141Or, if the function returns a filename, that filename will be invoked
142with the current command arguments rather than the command specified
143by the user on the command line."
144  :type 'hook
145  :group 'eshell-ext)
146
147(defcustom eshell-command-interpreter-max-length 256
148  "*The maximum length of any command interpreter string, plus args."
149  :type 'integer
150  :group 'eshell-ext)
151
152(defcustom eshell-explicit-command-char ?*
153  "*If this char occurs before a command name, call it externally.
154That is, although `vi' may be an alias, `\vi' will always call the
155external version."
156  :type 'character
157  :group 'eshell-ext)
158
159;;; Functions:
160
161(defun eshell-ext-initialize ()
162  "Initialize the external command handling code."
163  (add-hook 'eshell-named-command-hook 'eshell-explicit-command nil t))
164
165(defun eshell-explicit-command (command args)
166  "If a command name begins with `*', call it externally always.
167This bypasses all Lisp functions and aliases."
168  (when (and (> (length command) 1)
169	     (eq (aref command 0) eshell-explicit-command-char))
170    (let ((cmd (eshell-search-path (substring command 1))))
171      (if cmd
172	  (or (eshell-external-command cmd args)
173	      (error "%s: external command failed" cmd))
174	(error "%s: external command not found"
175	       (substring command 1))))))
176
177(defun eshell-remote-command (handler command args)
178  "Insert output from a remote COMMAND, using ARGS.
179A remote command is something that executes on a different machine.
180An external command simply means external to Emacs.
181
182Note that this function is very crude at the moment.  It gathers up
183all the output from the remote command, and sends it all at once,
184causing the user to wonder if anything's really going on..."
185  (let ((outbuf (generate-new-buffer " *eshell remote output*"))
186	(errbuf (generate-new-buffer " *eshell remote error*"))
187	(exitcode 1))
188    (unwind-protect
189	(progn
190	  (setq exitcode
191		(funcall handler 'shell-command
192			 (mapconcat 'shell-quote-argument
193				    (append (list command) args) " ")
194			 outbuf errbuf))
195	  (eshell-print (save-excursion (set-buffer outbuf)
196					(buffer-string)))
197	  (eshell-error (save-excursion (set-buffer errbuf)
198					(buffer-string))))
199      (eshell-close-handles exitcode 'nil)
200      (kill-buffer outbuf)
201      (kill-buffer errbuf))))
202
203(defun eshell-external-command (command args)
204  "Insert output from an external COMMAND, using ARGS."
205  (setq args (eshell-stringify-list (eshell-flatten-list args)))
206  (let ((handler
207	 (unless (or (equal default-directory "/")
208		     (and (eshell-under-windows-p)
209			  (string-match "\\`[A-Za-z]:[/\\\\]\\'"
210					default-directory)))
211	   (find-file-name-handler default-directory
212				   'shell-command))))
213    (if (and handler
214	     (not (and (eshell-under-xemacs-p)
215		       (eq handler 'dired-handler-fn))))
216	(eshell-remote-command handler command args))
217    (let ((interp (eshell-find-interpreter command)))
218      (assert interp)
219      (if (functionp (car interp))
220	  (apply (car interp) (append (cdr interp) args))
221	(eshell-gather-process-output
222	 (car interp) (append (cdr interp) args))))))
223
224(defun eshell/addpath (&rest args)
225  "Add a set of paths to PATH."
226  (eshell-eval-using-options
227   "addpath" args
228   '((?b "begin" nil prepend "add path element at beginning")
229     (?h "help" nil nil  "display this usage message")
230     :usage "[-b] PATH
231Adds the given PATH to $PATH.")
232   (if args
233       (progn
234	 (if prepend
235	     (setq args (nreverse args)))
236	 (while args
237	   (setenv "PATH"
238		   (if prepend
239		       (concat (car args) path-separator
240			       (getenv "PATH"))
241		     (concat (getenv "PATH") path-separator
242			     (car args))))
243	   (setq args (cdr args))))
244     (let ((paths (parse-colon-path (getenv "PATH"))))
245       (while paths
246	 (eshell-printn (car paths))
247	 (setq paths (cdr paths)))))))
248
249(put 'eshell/addpath 'eshell-no-numeric-conversions t)
250
251(defun eshell-script-interpreter (file)
252  "Extract the script to run from FILE, if it has #!<interp> in it.
253Return nil, or a list of the form:
254
255  (INTERPRETER [ARGS] FILE)"
256  (let ((maxlen eshell-command-interpreter-max-length))
257    (if (and (file-readable-p file)
258	     (file-regular-p file))
259	(with-temp-buffer
260	  (insert-file-contents-literally file nil 0 maxlen)
261	  (if (looking-at "#![ \t]*\\([^ \r\t\n]+\\)\\([ \t]+\\(.+\\)\\)?")
262	      (if (match-string 3)
263		  (list (match-string 1)
264			(match-string 3)
265			file)
266		(list (match-string 1)
267		      file)))))))
268
269(defun eshell-find-interpreter (file &optional no-examine-p)
270  "Find the command interpreter with which to execute FILE.
271If NO-EXAMINE-P is non-nil, FILE will not be inspected for a script
272line of the form #!<interp>."
273  (let ((finterp
274	 (catch 'found
275	   (ignore
276	    (eshell-for possible eshell-interpreter-alist
277	      (cond
278	       ((functionp (car possible))
279		(and (funcall (car possible) file)
280		     (throw 'found (cdr possible))))
281	       ((stringp (car possible))
282		(and (string-match (car possible) file)
283		     (throw 'found (cdr possible))))
284	       (t
285		(error "Invalid interpreter-alist test"))))))))
286    (if finterp                         ; first check
287	(list finterp file)
288      (let ((fullname (if (file-name-directory file) file
289			(eshell-search-path file)))
290	    (suffixes eshell-binary-suffixes))
291	(if (and fullname (not (or eshell-force-execution
292				   (file-executable-p fullname))))
293	    (while suffixes
294	      (let ((try (concat fullname (car suffixes))))
295		(if (or (file-executable-p try)
296			(and eshell-force-execution
297			     (file-readable-p try)))
298		    (setq fullname try suffixes nil)
299		  (setq suffixes (cdr suffixes))))))
300	(cond ((not (and fullname (file-exists-p fullname)))
301	       (let ((name (or fullname file)))
302		 (unless (setq fullname
303			       (run-hook-with-args-until-success
304				'eshell-alternate-command-hook file))
305		   (error "%s: command not found" name))))
306	      ((not (or eshell-force-execution
307			(file-executable-p fullname)))
308	       (error "%s: Permission denied" fullname)))
309	(let (interp)
310	  (unless no-examine-p
311	    (setq interp (eshell-script-interpreter fullname))
312	    (if interp
313		(setq interp
314		      (cons (car (eshell-find-interpreter (car interp) t))
315			    (cdr interp)))))
316	  (or interp (list fullname)))))))
317
318;;; Code:
319
320;;; arch-tag: 178d4064-7e60-4745-b81f-bab5d8d7c40f
321;;; esh-ext.el ends here
322