root/trunk/lisp/gnus/gnus-agent.el

;;; gnus-agent.el --- unplugged support for Gnus

;; Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
;;   2005, 2006, 2007, 2008 Free Software Foundation, Inc.

;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
;; 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 3, 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., 51 Franklin Street, Fifth Floor,
;; Boston, MA 02110-1301, USA.

;;; Commentary:

;;; Code:

(require 'gnus)
(require 'gnus-cache)
(require 'nnmail)
(require 'nnvirtual)
(require 'gnus-sum)
(require 'gnus-score)
(require 'gnus-srvr)
(require 'gnus-util)
(eval-when-compile
  (if (featurep 'xemacs)
      (require 'itimer)
    (require 'timer))
  (require 'cl))

(eval-and-compile
  (autoload 'gnus-server-update-server "gnus-srvr")
  (autoload 'gnus-agent-customize-category "gnus-cus")
)

(defcustom gnus-agent-directory (nnheader-concat gnus-directory "agent/")
  "Where the Gnus agent will store its files."
  :group 'gnus-agent
  :type 'directory)

(defcustom gnus-agent-plugged-hook nil
  "Hook run when plugging into the network."
  :group 'gnus-agent
  :type 'hook)

(defcustom gnus-agent-unplugged-hook nil
  "Hook run when unplugging from the network."
  :group 'gnus-agent
  :type 'hook)

(defcustom gnus-agent-fetched-hook nil
  "Hook run when finished fetching articles."
  :version "22.1"
  :group 'gnus-agent
  :type 'hook)

(defcustom gnus-agent-handle-level gnus-level-subscribed
  "Groups on levels higher than this variable will be ignored by the Agent."
  :group 'gnus-agent
  :type 'integer)

(defcustom gnus-agent-expire-days 7
  "Read articles older than this will be expired.
If you wish to disable Agent expiring, see `gnus-agent-enable-expiration'."
  :group 'gnus-agent
  :type '(number :tag "days"))

(defcustom gnus-agent-expire-all nil
  "If non-nil, also expire unread, ticked and dormant articles.
If nil, only read articles will be expired."
  :group 'gnus-agent
  :type 'boolean)

(defcustom gnus-agent-group-mode-hook nil
  "Hook run in Agent group minor modes."
  :group 'gnus-agent
  :type 'hook)

;; Extracted from gnus-xmas-redefine in order to preserve user settings
(when (featurep 'xemacs)
  (add-hook 'gnus-agent-group-mode-hook 'gnus-xmas-agent-group-menu-add))

(defcustom gnus-agent-summary-mode-hook nil
  "Hook run in Agent summary minor modes."
  :group 'gnus-agent
  :type 'hook)

;; Extracted from gnus-xmas-redefine in order to preserve user settings
(when (featurep 'xemacs)
  (add-hook 'gnus-agent-summary-mode-hook 'gnus-xmas-agent-summary-menu-add))

(defcustom gnus-agent-server-mode-hook nil
  "Hook run in Agent summary minor modes."
  :group 'gnus-agent
  :type 'hook)

;; Extracted from gnus-xmas-redefine in order to preserve user settings
(when (featurep 'xemacs)
  (add-hook 'gnus-agent-server-mode-hook 'gnus-xmas-agent-server-menu-add))

(defcustom gnus-agent-confirmation-function 'y-or-n-p
  "Function to confirm when error happens."
  :version "21.1"
  :group 'gnus-agent
  :type 'function)

(defcustom gnus-agent-synchronize-flags t
  "Indicate if flags are synchronized when you plug in.
If this is `ask' the hook will query the user."
  ;; If the default switches to something else than nil, then the function
  ;; should be fixed not be exceedingly slow.  See 2005-09-20 ChangeLog entry.
  :version "21.1"
  :type '(choice (const :tag "Always" t)
                 (const :tag "Never" nil)
                 (const :tag "Ask" ask))
  :group 'gnus-agent)

(defcustom gnus-agent-go-online 'ask
  "Indicate if offline servers go online when you plug in.
If this is `ask' the hook will query the user."
  :version "21.3"
  :type '(choice (const :tag "Always" t)
                 (const :tag "Never" nil)
                 (const :tag "Ask" ask))
  :group 'gnus-agent)

(defcustom gnus-agent-mark-unread-after-downloaded t
  "Indicate whether to mark articles unread after downloaded."
  :version "21.1"
  :type 'boolean
  :group 'gnus-agent)

(defcustom gnus-agent-download-marks '(download)
  "Marks for downloading."
  :version "21.1"
  :type '(repeat (symbol :tag "Mark"))
  :group 'gnus-agent)

(defcustom gnus-agent-consider-all-articles nil
  "When non-nil, the agent will let the agent predicate decide
whether articles need to be downloaded or not, for all articles.  When
nil, the default, the agent will only let the predicate decide
whether unread articles are downloaded or not.  If you enable this,
groups with large active ranges may open slower and you may also want
to look into the agent expiry settings to block the expiration of
read articles as they would just be downloaded again."
  :version "22.1"
  :type 'boolean
  :group 'gnus-agent)

(defcustom gnus-agent-max-fetch-size 10000000 ;; 10 Mb
  "Chunk size for `gnus-agent-fetch-session'.
The function will split its article fetches into chunks smaller than
this limit."
  :version "22.1"
  :group 'gnus-agent
  :type 'integer)

(defcustom gnus-agent-enable-expiration 'ENABLE
  "The default expiration state for each group.
When set to ENABLE, the default, `gnus-agent-expire' will expire old
contents from a group's local storage.  This value may be overridden
to disable expiration in specific categories, topics, and groups.  Of
course, you could change gnus-agent-enable-expiration to DISABLE then
enable expiration per categories, topics, and groups."
  :version "22.1"
  :group 'gnus-agent
  :type '(radio (const :format "Enable " ENABLE)
                (const :format "Disable " DISABLE)))

(defcustom gnus-agent-expire-unagentized-dirs t
  "*Whether expiration should expire in unagentized directories.
Have gnus-agent-expire scan the directories under
\(gnus-agent-directory) for groups that are no longer agentized.
When found, offer to remove them."
  :version "22.1"
  :type 'boolean
  :group 'gnus-agent)

(defcustom gnus-agent-auto-agentize-methods '(nntp nnimap)
  "Initially, all servers from these methods are agentized.
The user may remove or add servers using the Server buffer.
See Info node `(gnus)Server Buffer'."
  :version "22.1"
  :type '(repeat symbol)
  :group 'gnus-agent)

(defcustom gnus-agent-queue-mail t
  "Whether and when outgoing mail should be queued by the agent.
When `always', always queue outgoing mail.  When nil, never
queue.  Otherwise, queue if and only if unplugged."
  :version "22.1"
  :group 'gnus-agent
  :type '(radio (const :format "Always" always)
                (const :format "Never" nil)
                (const :format "When unplugged" t)))

(defcustom gnus-agent-prompt-send-queue nil
  "If non-nil, `gnus-group-send-queue' will prompt if called when
unplugged."
  :version "22.1"
  :group 'gnus-agent
  :type 'boolean)

(defcustom gnus-agent-article-alist-save-format 1
  "Indicates whether to use compression(2), versus no
compression(1), when writing agentview files.  The compressed
files do save space but load times are 6-7 times higher.  A group
must be opened then closed for the agentview to be updated using
the new format."
  ;; Wouldn't symbols instead numbers be nicer?  --rsteib
  :version "22.1"
  :group 'gnus-agent
  :type '(radio (const :format "Compressed" 2)
                (const :format "Uncompressed" 1)))

;;; Internal variables

(defvar gnus-agent-history-buffers nil)
(defvar gnus-agent-buffer-alist nil)
(defvar gnus-agent-article-alist nil
  "An assoc list identifying the articles whose headers have been fetched.
If successfully fetched, these headers will be stored in the group's overview
file.  The key of each assoc pair is the article ID, the value of each assoc
pair is a flag indicating whether the identified article has been downloaded
\(gnus-agent-fetch-articles sets the value to the day of the download).
NOTES:
1) The last element of this list can not be expired as some
   routines (for example, get-agent-fetch-headers) use the last
   value to track which articles have had their headers retrieved.
2) The function `gnus-agent-regenerate' may destructively modify the value.")
(defvar gnus-agent-group-alist nil)
(defvar gnus-category-alist nil)
(defvar gnus-agent-current-history nil)
(defvar gnus-agent-overview-buffer nil)
(defvar gnus-category-predicate-cache nil)
(defvar gnus-category-group-cache nil)
(defvar gnus-agent-spam-hashtb nil)
(defvar gnus-agent-file-name nil)
(defvar gnus-agent-send-mail-function nil)
(defvar gnus-agent-file-coding-system 'raw-text)
(defvar gnus-agent-file-loading-cache nil)

;; Dynamic variables
(defvar gnus-headers)
(defvar gnus-score)

;;;
;;; Setup
;;;

(defun gnus-open-agent ()
  (setq gnus-agent t)
  (gnus-agent-read-servers)
  (gnus-category-read)
  (gnus-agent-create-buffer)
  (add-hook 'gnus-group-mode-hook 'gnus-agent-mode)
  (add-hook 'gnus-summary-mode-hook 'gnus-agent-mode)
  (add-hook 'gnus-server-mode-hook 'gnus-agent-mode))

(defun gnus-agent-create-buffer ()
  (if (gnus-buffer-live-p gnus-agent-overview-buffer)
      t
    (setq gnus-agent-overview-buffer
          (gnus-get-buffer-create " *Gnus agent overview*"))
    (with-current-buffer gnus-agent-overview-buffer
      (mm-enable-multibyte))
    nil))

(gnus-add-shutdown 'gnus-close-agent 'gnus)

(defun gnus-close-agent ()
  (setq gnus-category-predicate-cache nil
        gnus-category-group-cache nil
        gnus-agent-spam-hashtb nil)
  (gnus-kill-buffer gnus-agent-overview-buffer))

;;;
;;; Utility functions
;;;

(defun gnus-agent-read-file (file)
  "Load FILE and do a `read' there."
  (with-temp-buffer
    (ignore-errors
      (nnheader-insert-file-contents file)
      (goto-char (point-min))
      (read (current-buffer)))))

(defsubst gnus-agent-method ()
  (concat (symbol-name (car gnus-command-method)) "/"
          (if (equal (cadr gnus-command-method) "")
              "unnamed"
            (cadr gnus-command-method))))

(defsubst gnus-agent-directory ()
  "The name of the Gnus agent directory."
  (nnheader-concat gnus-agent-directory
                   (nnheader-translate-file-chars (gnus-agent-method)) "/"))

(defun gnus-agent-lib-file (file)
  "The full name of the Gnus agent library FILE."
  (expand-file-name file
                    (file-name-as-directory
                     (expand-file-name "agent.lib" (gnus-agent-directory)))))

(defun gnus-agent-cat-set-property (category property value)
  (if value
      (setcdr (or (assq property category)
              (let ((cell (cons property nil)))
                    (setcdr category (cons cell (cdr category)))
                    cell)) value)
    (let ((category category))
      (while (cond ((eq property (caadr category))
                    (setcdr category (cddr category))
                    nil)
                   (t
                    (setq category (cdr category)))))))
  category)

(eval-when-compile
  (defmacro gnus-agent-cat-defaccessor (name prop-name)
    "Define accessor and setter methods for manipulating a list of the form
\(NAME (PROPERTY1 VALUE1) ... (PROPERTY_N VALUE_N)).
Given the call (gnus-agent-cat-defaccessor func PROPERTY1), the list may be
manipulated as follows:
  (func LIST): Returns VALUE1
  (setf (func LIST) NEW_VALUE1): Replaces VALUE1 with NEW_VALUE1."
    `(progn (defmacro ,name (category)
              (list (quote cdr) (list (quote assq)
                                      (quote (quote ,prop-name)) category)))

            (define-setf-method ,name (category)
              (let* ((--category--temp-- (make-symbol "--category--"))
                     (--value--temp-- (make-symbol "--value--")))
                (list (list --category--temp--) ; temporary-variables
                      (list category)   ; value-forms
                      (list --value--temp--) ; store-variables
                      (let* ((category --category--temp--) ; store-form
                             (value --value--temp--))
                        (list (quote gnus-agent-cat-set-property)
                              category
                              (quote (quote ,prop-name))
                              value))
                      (list (quote ,name) --category--temp--) ; access-form
                      )))))
  )

(defmacro gnus-agent-cat-name (category)
  `(car ,category))

(gnus-agent-cat-defaccessor
 gnus-agent-cat-days-until-old             agent-days-until-old)
(gnus-agent-cat-defaccessor
 gnus-agent-cat-enable-expiration          agent-enable-expiration)
(gnus-agent-cat-defaccessor
 gnus-agent-cat-groups                     agent-groups)
(gnus-agent-cat-defaccessor
 gnus-agent-cat-high-score                 agent-high-score)
(gnus-agent-cat-defaccessor
 gnus-agent-cat-length-when-long           agent-long-article)
(gnus-agent-cat-defaccessor
 gnus-agent-cat-length-when-short          agent-short-article)
(gnus-agent-cat-defaccessor
 gnus-agent-cat-low-score                  agent-low-score)
(gnus-agent-cat-defaccessor
 gnus-agent-cat-predicate                  agent-predicate)
(gnus-agent-cat-defaccessor
 gnus-agent-cat-score-file                 agent-score)
(gnus-agent-cat-defaccessor
 gnus-agent-cat-enable-undownloaded-faces  agent-enable-undownloaded-faces)


;; This form is equivalent to defsetf except that it calls make-symbol
;; whereas defsetf calls gensym (Using gensym creates a run-time
;; dependency on the CL library).

(eval-and-compile
  (define-setf-method gnus-agent-cat-groups (category)
    (let* ((--category--temp-- (make-symbol "--category--"))
           (--groups--temp-- (make-symbol "--groups--")))
      (list (list --category--temp--)
            (list category)
            (list --groups--temp--)
            (let* ((category --category--temp--)
                   (groups --groups--temp--))
              (list (quote gnus-agent-set-cat-groups) category groups))
            (list (quote gnus-agent-cat-groups) --category--temp--))))
  )

(defun gnus-agent-set-cat-groups (category groups)
  (unless (eq groups 'ignore)
    (let ((new-g groups)
          (old-g (gnus-agent-cat-groups category)))
      (cond ((eq new-g old-g)
             ;; gnus-agent-add-group is fiddling with the group
             ;; list. Still, Im done.
             nil
             )
            ((eq new-g (cdr old-g))
             ;; gnus-agent-add-group is fiddling with the group list
             (setcdr (or (assq 'agent-groups category)
                         (let ((cell (cons 'agent-groups nil)))
                           (setcdr category (cons cell (cdr category)))
                           cell)) new-g))
            (t
             (let ((groups groups))
               (while groups
                 (let* ((group        (pop groups))
                        (old-category (gnus-group-category group)))
                   (if (eq category old-category)
                       nil
                     (setf (gnus-agent-cat-groups old-category)
                           (delete group (gnus-agent-cat-groups
                                          old-category))))))
               ;; Purge cache as preceeding loop invalidated it.
               (setq gnus-category-group-cache nil))

             (setcdr (or (assq 'agent-groups category)
                         (let ((cell (cons 'agent-groups nil)))
                           (setcdr category (cons cell (cdr category)))
                           cell)) groups))))))

(defsubst gnus-agent-cat-make (name &optional default-agent-predicate)
  (list name `(agent-predicate . ,(or default-agent-predicate 'false))))

;;; Fetching setup functions.

(defun gnus-agent-start-fetch ()
  "Initialize data structures for efficient fetching."
  (gnus-agent-create-buffer))

(defun gnus-agent-stop-fetch ()
  "Save all data structures and clean up."
  (setq gnus-agent-spam-hashtb nil)
  (save-excursion
    (set-buffer nntp-server-buffer)
    (widen)))

(defmacro gnus-agent-with-fetch (&rest forms)
  "Do FORMS safely."
  `(unwind-protect
       (let ((gnus-agent-fetching t))
         (gnus-agent-start-fetch)
         ,@forms)
     (gnus-agent-stop-fetch)))

(put 'gnus-agent-with-fetch 'lisp-indent-function 0)
(put 'gnus-agent-with-fetch 'edebug-form-spec '(body))

(defmacro gnus-agent-append-to-list (tail value)
  `(setq ,tail (setcdr ,tail (cons ,value nil))))

(defmacro gnus-agent-message (level &rest args)
  `(if (<= ,level gnus-verbose)
       (message ,@args)))

;;;
;;; Mode infestation
;;;

(defvar gnus-agent-mode-hook nil
  "Hook run when installing agent mode.")

(defvar gnus-agent-mode nil)
(defvar gnus-agent-mode-status '(gnus-agent-mode " Plugged"))

(defun gnus-agent-mode ()
  "Minor mode for providing a agent support in Gnus buffers."
  (let* ((buffer (progn (string-match "^gnus-\\(.*\\)-mode$"
                                      (symbol-name major-mode))
                        (match-string 1 (symbol-name major-mode))))
         (mode (intern (format "gnus-agent-%s-mode" buffer))))
    (set (make-local-variable 'gnus-agent-mode) t)
    (set mode nil)
    (set (make-local-variable mode) t)
    ;; Set up the menu.
    (when (gnus-visual-p 'agent-menu 'menu)
      (funcall (intern (format "gnus-agent-%s-make-menu-bar" buffer))))
    (unless (assq 'gnus-agent-mode minor-mode-alist)
      (push gnus-agent-mode-status minor-mode-alist))
    (unless (assq mode minor-mode-map-alist)
      (push (cons mode (symbol-value (intern (format "gnus-agent-%s-mode-map"
                                                     buffer))))
            minor-mode-map-alist))
    (when (eq major-mode 'gnus-group-mode)
      (let ((init-plugged gnus-plugged)
            (gnus-agent-go-online nil))
        ;; g-a-t-p does nothing when gnus-plugged isn't changed.
        ;; Therefore, make certain that the current value does not
        ;; match the desired initial value.
        (setq gnus-plugged :unknown)
        (gnus-agent-toggle-plugged init-plugged)))
    (gnus-run-hooks 'gnus-agent-mode-hook
                    (intern (format "gnus-agent-%s-mode-hook" buffer)))))

(defvar gnus-agent-group-mode-map (make-sparse-keymap))
(gnus-define-keys gnus-agent-group-mode-map
  "Ju" gnus-agent-fetch-groups
  "Jc" gnus-enter-category-buffer
  "Jj" gnus-agent-toggle-plugged
  "Js" gnus-agent-fetch-session
  "JY" gnus-agent-synchronize-flags
  "JS" gnus-group-send-queue
  "Ja" gnus-agent-add-group
  "Jr" gnus-agent-remove-group
  "Jo" gnus-agent-toggle-group-plugged)

(defun gnus-agent-group-make-menu-bar ()
  (unless (boundp 'gnus-agent-group-menu)
    (easy-menu-define
     gnus-agent-group-menu gnus-agent-group-mode-map ""
     '("Agent"
       ["Toggle plugged" gnus-agent-toggle-plugged t]
       ["Toggle group plugged" gnus-agent-toggle-group-plugged t]
       ["List categories" gnus-enter-category-buffer t]
       ["Add (current) group to category" gnus-agent-add-group t]
       ["Remove (current) group from category" gnus-agent-remove-group t]
       ["Send queue" gnus-group-send-queue gnus-plugged]
       ("Fetch"
        ["All" gnus-agent-fetch-session gnus-plugged]
        ["Group" gnus-agent-fetch-group gnus-plugged])
       ["Synchronize flags" gnus-agent-synchronize-flags t]
       ))))

(defvar gnus-agent-summary-mode-map (make-sparse-keymap))
(gnus-define-keys gnus-agent-summary-mode-map
  "Jj" gnus-agent-toggle-plugged
  "Ju" gnus-agent-summary-fetch-group
  "JS" gnus-agent-fetch-group
  "Js" gnus-agent-summary-fetch-series
  "J#" gnus-agent-mark-article
  "J\M-#" gnus-agent-unmark-article
  "@" gnus-agent-toggle-mark
  "Jc" gnus-agent-catchup)

(defun gnus-agent-summary-make-menu-bar ()
  (unless (boundp 'gnus-agent-summary-menu)
    (easy-menu-define
     gnus-agent-summary-menu gnus-agent-summary-mode-map ""
     '("Agent"
       ["Toggle plugged" gnus-agent-toggle-plugged t]
       ["Mark as downloadable" gnus-agent-mark-article t]
       ["Unmark as downloadable" gnus-agent-unmark-article t]
       ["Toggle mark" gnus-agent-toggle-mark t]
       ["Fetch downloadable" gnus-agent-summary-fetch-group t]
       ["Catchup undownloaded" gnus-agent-catchup t]))))

(defvar gnus-agent-server-mode-map (make-sparse-keymap))
(gnus-define-keys gnus-agent-server-mode-map
  "Jj" gnus-agent-toggle-plugged
  "Ja" gnus-agent-add-server
  "Jr" gnus-agent-remove-server)

(defun gnus-agent-server-make-menu-bar ()
  (unless (boundp 'gnus-agent-server-menu)
    (easy-menu-define
     gnus-agent-server-menu gnus-agent-server-mode-map ""
     '("Agent"
       ["Toggle plugged" gnus-agent-toggle-plugged t]
       ["Add" gnus-agent-add-server t]
       ["Remove" gnus-agent-remove-server t]))))

(defun gnus-agent-make-mode-line-string (string mouse-button mouse-func)
  (if (and (fboundp 'propertize)
           (fboundp 'make-mode-line-mouse-map))
      (propertize string 'local-map
                  (make-mode-line-mouse-map mouse-button mouse-func)
                  'mouse-face
                  (cond ((and (featurep 'xemacs)
                              ;; XEmacs' `facep' only checks for a face
                              ;; object, not for a face name, so it's useless
                              ;; to check with `facep'.
                              (find-face 'modeline))
                         'modeline)
                        ((facep 'mode-line-highlight) ;; Emacs 22
                         'mode-line-highlight)
                        ((facep 'mode-line) ;; Emacs 21
                         'mode-line)) )
    string))

(defun gnus-agent-toggle-plugged (set-to)
  "Toggle whether Gnus is unplugged or not."
  (interactive (list (not gnus-plugged)))
  (cond ((eq set-to gnus-plugged)
         nil)
        (set-to
         (setq gnus-plugged set-to)
         (gnus-run-hooks 'gnus-agent-plugged-hook)
         (setcar (cdr gnus-agent-mode-status)
                 (gnus-agent-make-mode-line-string " Plugged"
                                                   'mouse-2
                                                   'gnus-agent-toggle-plugged))
         (gnus-agent-go-online gnus-agent-go-online)
         (gnus-agent-possibly-synchronize-flags))
        (t
         (gnus-agent-close-connections)
         (setq gnus-plugged set-to)
         (gnus-run-hooks 'gnus-agent-unplugged-hook)
         (setcar (cdr gnus-agent-mode-status)
                 (gnus-agent-make-mode-line-string " Unplugged"
                                                   'mouse-2
                                                   'gnus-agent-toggle-plugged))))
  (set-buffer-modified-p t))

(defmacro gnus-agent-while-plugged (&rest body)
  `(let ((original-gnus-plugged gnus-plugged))
    (unwind-protect
        (progn (gnus-agent-toggle-plugged t)
               ,@body)
      (gnus-agent-toggle-plugged original-gnus-plugged))))

(put 'gnus-agent-while-plugged 'lisp-indent-function 0)
(put 'gnus-agent-while-plugged 'edebug-form-spec '(body))

(defun gnus-agent-close-connections ()
  "Close all methods covered by the Gnus agent."
  (let ((methods (gnus-agent-covered-methods)))
    (while methods
      (gnus-close-server (pop methods)))))

;;;###autoload
(defun gnus-unplugged ()
  "Start Gnus unplugged."
  (interactive)
  (setq gnus-plugged nil)
  (gnus))

;;;###autoload
(defun gnus-plugged ()
  "Start Gnus plugged."
  (interactive)
  (setq gnus-plugged t)
  (gnus))

;;;###autoload
(defun gnus-slave-unplugged (&optional arg)
  "Read news as a slave unplugged."
  (interactive "P")
  (setq gnus-plugged nil)
  (gnus arg nil 'slave))

;;;###autoload
(defun gnus-agentize ()
  "Allow Gnus to be an offline newsreader.

The gnus-agentize function is now called internally by gnus when
gnus-agent is set.  If you wish to avoid calling gnus-agentize,
customize gnus-agent to nil.

This will modify the `gnus-setup-news-hook', and
`message-send-mail-real-function' variables, and install the Gnus agent
minor mode in all Gnus buffers."
  (interactive)
  (gnus-open-agent)
  (add-hook 'gnus-setup-news-hook 'gnus-agent-queue-setup)
  (unless gnus-agent-send-mail-function
    (setq gnus-agent-send-mail-function
          (or message-send-mail-real-function
              (function (lambda () (funcall message-send-mail-function))))
          message-send-mail-real-function 'gnus-agent-send-mail))

  ;; If the servers file doesn't exist, auto-agentize some servers and
  ;; save the servers file so this auto-agentizing isn't invoked
  ;; again.
  (unless (file-exists-p (nnheader-concat gnus-agent-directory "lib/servers"))
    (gnus-message 3 "First time agent user, agentizing remote groups...")
    (mapc
     (lambda (server-or-method)
       (let ((method (gnus-server-to-method server-or-method)))
         (when (memq (car method)
                     gnus-agent-auto-agentize-methods)
           (push (gnus-method-to-server method)
                 gnus-agent-covered-methods)
           (setq gnus-agent-method-p-cache nil))))
     (cons gnus-select-method gnus-secondary-select-methods))
    (gnus-agent-write-servers)))

(defun gnus-agent-queue-setup (&optional group-name)
  "Make sure the queue group exists.
Optional arg GROUP-NAME allows to specify another group."
  (unless (gnus-gethash (format "nndraft:%s" (or group-name "queue"))
                        gnus-newsrc-hashtb)
    (gnus-request-create-group (or group-name "queue") '(nndraft ""))
    (let ((gnus-level-default-subscribed 1))
      (gnus-subscribe-group (format "nndraft:%s" (or group-name "queue"))
                            nil '(nndraft "")))
    (gnus-group-set-parameter
     (format "nndraft:%s" (or group-name "queue"))
     'gnus-dummy '((gnus-draft-mode)))))

(defun gnus-agent-send-mail ()
  (if (or (not gnus-agent-queue-mail)
          (and gnus-plugged (not (eq gnus-agent-queue-mail 'always))))
      (funcall gnus-agent-send-mail-function)
    (goto-char (point-min))
    (re-search-forward
     (concat "^" (regexp-quote mail-header-separator) "\n"))
    (replace-match "\n")
    (gnus-agent-insert-meta-information 'mail)
    (gnus-request-accept-article "nndraft:queue" nil t t)))

(defun gnus-agent-insert-meta-information (type &optional method)
  "Insert meta-information into the message that says how it's to be posted.
TYPE can be either `mail' or `news'.  If the latter, then METHOD can
be a select method."
  (save-excursion
    (message-remove-header gnus-agent-meta-information-header)
    (goto-char (point-min))
    (insert gnus-agent-meta-information-header ": "
            (symbol-name type) " " (format "%S" method)
            "\n")
    (forward-char -1)
    (while (search-backward "\n" nil t)
      (replace-match "\\n" t t))))

(defun gnus-agent-restore-gcc ()
  "Restore GCC field from saved header."
  (save-excursion
    (goto-char (point-min))
    (while (re-search-forward
            (concat "^" (regexp-quote gnus-agent-gcc-header) ":") nil t)
      (replace-match "Gcc:" 'fixedcase))))

(defun gnus-agent-any-covered-gcc ()
  (save-restriction
    (message-narrow-to-headers)
    (let* ((gcc (mail-fetch-field "gcc" nil t))
           (methods (and gcc
                         (mapcar 'gnus-inews-group-method
                                 (message-unquote-tokens
                                  (message-tokenize-header
                                   gcc " ,")))))
           covered)
      (while (and (not covered) methods)
        (setq covered (gnus-agent-method-p (car methods))
              methods (cdr methods)))
      covered)))

;;;###autoload
(defun gnus-agent-possibly-save-gcc ()
  "Save GCC if Gnus is unplugged."
  (when (and (not gnus-plugged) (gnus-agent-any-covered-gcc))
    (save-excursion
      (goto-char (point-min))
      (let ((case-fold-search t))
        (while (re-search-forward "^gcc:" nil t)
          (replace-match (concat gnus-agent-gcc-header ":") 'fixedcase))))))

(defun gnus-agent-possibly-do-gcc ()
  "Do GCC if Gnus is plugged."
  (when (or gnus-plugged (not (gnus-agent-any-covered-gcc)))
    (gnus-inews-do-gcc)))

;;;
;;; Group mode commands
;;;

(defun gnus-agent-fetch-groups (n)
  "Put all new articles in the current groups into the Agent."
  (interactive "P")
  (unless gnus-plugged
    (error "Groups can't be fetched when Gnus is unplugged"))
  (gnus-group-iterate n 'gnus-agent-fetch-group))

(defun gnus-agent-fetch-group (&optional group)
  "Put all new articles in GROUP into the Agent."
  (interactive (list (gnus-group-group-name)))
  (setq group (or group gnus-newsgroup-name))
  (unless group
    (error "No group on the current line"))

  (gnus-agent-while-plugged
    (let ((gnus-command-method (gnus-find-method-for-group group)))
      (gnus-agent-with-fetch
        (gnus-agent-fetch-group-1 group gnus-command-method)
        (gnus-message 5 "Fetching %s...done" group)))))

(defun gnus-agent-add-group (category arg)
  "Add the current group to an agent category."
  (interactive
   (list
    (intern
     (completing-read
      "Add to category: "
      (mapcar (lambda (cat) (list (symbol-name (car cat))))
              gnus-category-alist)
      nil t))
    current-prefix-arg))
  (let ((cat (assq category gnus-category-alist))
        c groups)
    (gnus-group-iterate arg
      (lambda (group)
        (when (gnus-agent-cat-groups (setq c (gnus-group-category group)))
          (setf (gnus-agent-cat-groups c)
                (delete group (gnus-agent-cat-groups c))))
        (push group groups)))
    (setf (gnus-agent-cat-groups cat)
          (nconc (gnus-agent-cat-groups cat) groups))
    (gnus-category-write)))

(defun gnus-agent-remove-group (arg)
  "Remove the current group from its agent category, if any."
  (interactive "P")
  (let (c)
    (gnus-group-iterate arg
      (lambda (group)
        (when (gnus-agent-cat-groups (setq c (gnus-group-category group)))
          (setf (gnus-agent-cat-groups c)
                (delete group (gnus-agent-cat-groups c))))))
    (gnus-category-write)))

(defun gnus-agent-synchronize-flags ()
  "Synchronize unplugged flags with servers."
  (interactive)
  (save-excursion
    (dolist (gnus-command-method (gnus-agent-covered-methods))
      (when (file-exists-p (gnus-agent-lib-file "flags"))
        (gnus-agent-synchronize-flags-server gnus-command-method)))))

(defun gnus-agent-possibly-synchronize-flags ()
  "Synchronize flags according to `gnus-agent-synchronize-flags'."
  (interactive)
  (save-excursion
    (dolist (gnus-command-method (gnus-agent-covered-methods))
      (when (and (file-exists-p (gnus-agent-lib-file "flags"))
                 (eq (gnus-server-status gnus-command-method) 'ok))
        (gnus-agent-possibly-synchronize-flags-server gnus-command-method)))))

(defun gnus-agent-synchronize-flags-server (method)
  "Synchronize flags set when unplugged for server."
  (let ((gnus-command-method method)
        (gnus-agent nil))
    (when (file-exists-p (gnus-agent-lib-file "flags"))
      (set-buffer (get-buffer-create " *Gnus Agent flag synchronize*"))
      (erase-buffer)
      (nnheader-insert-file-contents (gnus-agent-lib-file "flags"))
      (cond ((null gnus-plugged)
             (gnus-message
              1 "You must be plugged to synchronize flags with server %s"
              (nth 1 gnus-command-method)))
            ((null (gnus-check-server gnus-command-method))
             (gnus-message
              1 "Couldn't open server %s" (nth 1 gnus-command-method)))
            (t
             (condition-case err
                 (while t
                   (let ((bgn (point)))
                     (eval (read (current-buffer)))
                     (delete-region bgn (point))))
               (end-of-file
                (delete-file (gnus-agent-lib-file "flags")))
               (error
                (let ((file (gnus-agent-lib-file "flags")))
                  (write-region (point-min) (point-max)
                                (gnus-agent-lib-file "flags") nil 'silent)