--- /dev/null
+;;; password.el --- Read passwords from user, possibly using a password cache.
+
+;; Copyright (C) 1999, 2000, 2003 Free Software Foundation, Inc.
+
+;; Author: Simon Josefsson <simon@josefsson.org>
+;; Created: 2003-12-21
+;; Keywords: password cache passphrase key
+
+;; 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 2, 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, Inc., 59 Temple Place - Suite 330,
+;; Boston, MA 02111-1307, USA.
+
+;;; Commentary:
+
+;; Greatly influenced by pgg.el written by Daiki Ueno, with timer
+;; fixes for XEmacs by Katsumi Yamaoka. In fact, this is mostly just
+;; a rip-off.
+;;
+;; (password-read "Password? " "test")
+;; ;; Minibuffer prompt for password.
+;; => "foo"
+;;
+;; (password-cache-add "test" "foo")
+;; => nil
+;;
+;; (password-read "Password? " "test")
+;; ;; No minibuffer prompt
+;; => "foo"
+;;
+;; (password-read "Password? " "test")
+;; ;; No minibuffer prompt
+;; => "foo"
+;;
+;; ;; Wait `password-cache-expiry' seconds.
+;;
+;; (password-read "Password? " "test")
+;; ;; Minibuffer prompt for password is back.
+;; => "foo"
+
+;;; Code:
+
+(autoload 'run-at-time "timer")
+
+(eval-when-compile
+ (require 'cl))
+
+(defcustom password-cache t
+ "Whether to cache passwords."
+ :group 'password
+ :type 'boolean)
+
+(defcustom password-cache-expiry 16
+ "How many seconds passwords are cached, or nil to disable expiring.
+Whether passwords are cached at all is controlled by `password-cache'."
+ :group 'password
+ :type '(choice (const :tag "Never" nil)
+ (integer :tag "Seconds")))
+
+(defvar password-data (make-vector 7 0))
+
+(defun password-read (prompt &optional key)
+ "Read password, for use with KEY, from user, or from cache if wanted.
+KEY indicate the purpose of the password, so the cache can
+separate passwords. The cache is not used if KEY is nil. It is
+typically a string.
+The variable `password-cache' control whether the cache is used."
+ (or (and password-cache
+ key
+ (symbol-value (intern-soft key password-data)))
+ (read-passwd prompt)))
+
+(eval-when-compile
+ (defvar itimer-process)
+ (defvar itimer-timer)
+ (autoload 'delete-itimer "itimer")
+ (autoload 'itimer-driver-start "itimer")
+ (autoload 'itimer-value "itimer")
+ (autoload 'set-itimer-function "itimer")
+ (autoload 'set-itimer-function-arguments "itimer")
+ (autoload 'set-itimer-restart "itimer")
+ (autoload 'start-itimer "itimer"))
+
+(eval-and-compile
+ (defalias
+ 'password-run-at-time
+ (if (featurep 'xemacs)
+ (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 "password-run-at-time" 'ignore 5)))
+ (sleep-for 0.1) ;; Accept the timeout interrupt.
+ (prog1
+ (> (itimer-value itimer) 0)
+ (delete-itimer itimer))))
+ (error nil))
+ (lambda (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 "password-run-at-time"
+ function (if time (max time 1e-9) 1e-9)
+ repeat nil t args))
+ (lambda (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 "password-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)))))
+ 'run-at-time)))
+
+(defun password-cache-remove (key)
+ "Remove password indexed by KEY from password cache.
+This is typically run be a timer setup from `password-cache-add',
+but can be invoked at any time to forcefully remove passwords
+from the cache. This may be useful when it has been detected
+that a password is invalid, so that `password-read' query the
+user again."
+ (let ((password (symbol-value (intern-soft key password-data))))
+ (when password
+ (fillarray password ?_)
+ (unintern key password-data))))
+
+(defun password-cache-add (key password)
+ "Add password to cache.
+The password is removed by a timer after `password-cache-expiry'
+seconds."
+ (set (intern key password-data) password)
+ (when password-cache-expiry
+ (password-run-at-time password-cache-expiry nil
+ #'password-cache-remove
+ key))
+ nil)
+
+(provide 'password)
+
+;;; password.el ends here
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