Avoid crash on composition (backport from trunk).
[emacs.git] / lisp / password-cache.el
blob4d670bdf2bfc7b6a09b3aa50e2de0f7b635dd95f
1 ;;; password-cache.el --- Read passwords, possibly using a password cache.
3 ;; Copyright (C) 1999, 2000, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011
4 ;; Free Software Foundation, Inc.
6 ;; Author: Simon Josefsson <simon@josefsson.org>
7 ;; Created: 2003-12-21
8 ;; Keywords: password cache passphrase key
10 ;; This file is part of GNU Emacs.
12 ;; GNU Emacs is free software: you can redistribute it and/or modify
13 ;; it under the terms of the GNU General Public License as published by
14 ;; the Free Software Foundation, either version 3 of the License, or
15 ;; (at your option) any later version.
17 ;; GNU Emacs is distributed in the hope that it will be useful,
18 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
19 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 ;; GNU General Public License for more details.
22 ;; You should have received a copy of the GNU General Public License
23 ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
25 ;;; Commentary:
27 ;; Greatly influenced by pgg.el written by Daiki Ueno, with timer
28 ;; fixes for XEmacs by Katsumi Yamaoka. In fact, this is mostly just
29 ;; a rip-off.
31 ;; (password-read "Password? " "test")
32 ;; ;; Minibuffer prompt for password.
33 ;; => "foo"
35 ;; (password-cache-add "test" "foo")
36 ;; => nil
38 ;; (password-read "Password? " "test")
39 ;; ;; No minibuffer prompt
40 ;; => "foo"
42 ;; (password-read "Password? " "test")
43 ;; ;; No minibuffer prompt
44 ;; => "foo"
46 ;; ;; Wait `password-cache-expiry' seconds.
48 ;; (password-read "Password? " "test")
49 ;; ;; Minibuffer prompt for password is back.
50 ;; => "foo"
52 ;;; Code:
54 (defcustom password-cache t
55 "Whether to cache passwords."
56 :group 'password
57 :type 'boolean)
59 (defcustom password-cache-expiry 16
60 "How many seconds passwords are cached, or nil to disable expiring.
61 Whether passwords are cached at all is controlled by `password-cache'."
62 :group 'password
63 :type '(choice (const :tag "Never" nil)
64 (integer :tag "Seconds")))
66 (defvar password-data (make-vector 7 0))
68 (defun password-read-from-cache (key)
69 "Obtain passphrase for KEY from time-limited passphrase cache.
70 Custom variables `password-cache' and `password-cache-expiry'
71 regulate cache behavior."
72 (and password-cache
73 key
74 (symbol-value (intern-soft key password-data))))
76 (defun password-read (prompt &optional key)
77 "Read password, for use with KEY, from user, or from cache if wanted.
78 KEY indicate the purpose of the password, so the cache can
79 separate passwords. The cache is not used if KEY is nil. It is
80 typically a string.
81 The variable `password-cache' control whether the cache is used."
82 (or (password-read-from-cache key)
83 (read-passwd prompt)))
85 (defun password-read-and-add (prompt &optional key)
86 "Read password, for use with KEY, from user, or from cache if wanted.
87 Then store the password in the cache. Uses `password-read' and
88 `password-cache-add'. Custom variables `password-cache' and
89 `password-cache-expiry' regulate cache behavior.
91 Warning: the password is cached without checking that it is
92 correct. It is better to check the password before caching. If
93 you must use this function, take care to check passwords and
94 remove incorrect ones from the cache."
95 (let ((password (password-read prompt key)))
96 (when (and password key)
97 (password-cache-add key password))
98 password))
100 (make-obsolete 'password-read-and-add 'password-read "23.1")
102 (defun password-cache-remove (key)
103 "Remove password indexed by KEY from password cache.
104 This is typically run be a timer setup from `password-cache-add',
105 but can be invoked at any time to forcefully remove passwords
106 from the cache. This may be useful when it has been detected
107 that a password is invalid, so that `password-read' query the
108 user again."
109 (let ((password (symbol-value (intern-soft key password-data))))
110 (when password
111 (if (fboundp 'clear-string)
112 (clear-string password)
113 (fillarray password ?_))
114 (unintern key password-data))))
116 (defun password-cache-add (key password)
117 "Add password to cache.
118 The password is removed by a timer after `password-cache-expiry' seconds."
119 (when (and password-cache-expiry (null (intern-soft key password-data)))
120 (run-at-time password-cache-expiry nil
121 #'password-cache-remove
122 key))
123 (set (intern key password-data) password)
124 nil)
126 (defun password-reset ()
127 "Clear the password cache."
128 (interactive)
129 (fillarray password-data 0))
131 (provide 'password-cache)
133 ;; arch-tag: ab160494-16c8-4c68-a4a1-73eebf6686e5
134 ;;; password-cache.el ends here