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[gnus] / lisp / nnimap.el

;;; nnimap.el --- imap backend for Gnus
;; Copyright (C) 1998, 1999, 2000, 2001, 2002 Free Software Foundation, Inc.

;; Author: Simon Josefsson <jas@pdc.kth.se>
;;         Jim Radford <radford@robby.caltech.edu>
;; Keywords: mail

;; 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:

;; Todo, major things:
;;
;;   o Fix Gnus to view correct number of unread/total articles in group buffer
;;   o Fix Gnus to handle leading '.' in group names (fixed?)
;;   o Finish disconnected mode (moving articles between mailboxes unplugged)
;;   o Sieve
;;   o MIME (partial article fetches)
;;   o Split to other backends, different split rules for different
;;     servers/inboxes
;;
;; Todo, minor things:
;;
;;   o Don't require half of Gnus -- backends should be standalone
;;   o Verify that we don't use IMAP4rev1 specific things (RFC2060 App B)
;;   o Dont uid fetch 1,* in nnimap-retrive-groups (slow)
;;   o Split up big fetches (1,* header especially) in smaller chunks
;;   o What do I do with gnus-newsgroup-*?
;;   o Tell Gnus about new groups (how can we tell?)
;;   o Respooling (fix Gnus?) (unnecessary?)
;;   o Add support for the following: (if applicable)
;;       request-list-newsgroups, request-regenerate
;;       list-active-group,
;;       request-associate-buffer, request-restore-buffer,
;;   o Do The Right Thing when UIDVALIDITY changes (what's the right thing?)
;;   o Support RFC2221 (Login referrals)
;;   o IMAP2BIS compatibility? (RFC2061)
;;   o ACAP stuff (perhaps a different project, would be nice to ACAPify
;;     .newsrc.eld)
;;   o What about Gnus's article editing, can we support it?  NO!
;;   o Use \Draft to support the draft group??
;;   o Duplicate suppression
;;   o Rewrite UID SEARCH UID X as UID FETCH X (UID) for those with slow servers

;;; Code:

(require 'imap)
(require 'nnoo)
(require 'nnmail)
(require 'nnheader)
(require 'mm-util)
(require 'gnus)
(require 'gnus-range)
(require 'gnus-start)
(require 'gnus-int)

(nnoo-declare nnimap)

(defconst nnimap-version "nnimap 1.0")

(defgroup nnimap nil
  "Reading IMAP mail with Gnus."
  :group 'gnus)

(defvoo nnimap-address nil
  "Address of physical IMAP server.  If nil, use the virtual server's name.")

(defvoo nnimap-server-port nil
  "Port number on physical IMAP server.
If nil, defaults to 993 for SSL connections and 143 otherwise.")

;; Splitting variables

(defcustom nnimap-split-crosspost t
  "If non-nil, do crossposting if several split methods match the mail.
If nil, the first match found will be used."
  :group 'nnimap
  :type 'boolean)

(defcustom nnimap-split-inbox nil
  "Name of mailbox to split mail from.

Mail is read from this mailbox and split according to rules in
`nnimap-split-rule'.

This can be a string or a list of strings."
  :group 'nnimap
  :type '(choice (string)
                 (repeat string)))

(define-widget 'nnimap-strict-function 'function
  "This widget only matches values that are functionp.

Warning: This means that a value that is the symbol of a not yet
loaded function will not match.  Use with care."
  :match 'nnimap-strict-function-match)

(defun nnimap-strict-function-match (widget value)
  "Ignoring WIDGET, match if VALUE is a function."
  (functionp value))

(defcustom nnimap-split-rule nil
  "Mail will be split according to these rules.

Mail is read from mailbox(es) specified in `nnimap-split-inbox'.

If you'd like, for instance, one mail group for mail from the
\"gnus-imap\" mailing list, one group for junk mail and leave
everything else in the incoming mailbox, you could do something like
this:

\(setq nnimap-split-rule '((\"INBOX.gnus-imap\"   \"From:.*gnus-imap\")
                          (\"INBOX.junk\"        \"Subject:.*buy\")))

As you can see, `nnimap-split-rule' is a list of lists, where the
first element in each \"rule\" is the name of the IMAP mailbox (or the
symbol `junk' if you want to remove the mail), and the second is a
regexp that nnimap will try to match on the header to find a fit.

The second element can also be a function.  In that case, it will be
called narrowed to the headers with the first element of the rule as
the argument.  It should return a non-nil value if it thinks that the
mail belongs in that group.

This variable can also have a function as its value, the function will
be called with the headers narrowed and should return a group where it
thinks the article should be splitted to.  See `nnimap-split-fancy'.

To allow for different split rules on different virtual servers, and
even different split rules in different inboxes on the same server,
the syntax of this variable have been extended along the lines of:

\(setq nnimap-split-rule
      '((\"my1server\"    (\".*\"    ((\"ding\"    \"ding@gnus.org\")
                                  (\"junk\"    \"From:.*Simon\")))
        (\"my2server\"    (\"INBOX\" nnimap-split-fancy))
        (\"my[34]server\" (\".*\"    ((\"private\" \"To:.*Simon\")
                                  (\"junk\"    my-junk-func)))))

The virtual server name is in fact a regexp, so that the same rules
may apply to several servers.  In the example, the servers
\"my3server\" and \"my4server\" both use the same rules.  Similarly,
the inbox string is also a regexp.  The actual splitting rules are as
before, either a function, or a list with group/regexp or
group/function elements."
  :group 'nnimap
  :type '(choice :tag "Rule type"
                 (repeat :menu-tag "Single-server"
                         :tag "Single-server list"
                         (list (string :tag "Mailbox")
                               (choice :tag "Predicate"
                                       (regexp :tag "A regexp")
                                       (nnimap-strict-function :tag "A function"))))
                 (choice :menu-tag "A function"
                         :tag "A function"
                         (function-item nnimap-split-fancy)
                         (function-item nnmail-split-fancy)
                         (nnimap-strict-function :tag "User-defined function"))
                 (repeat :menu-tag "Multi-server (extended)"
                         :tag "Multi-server list"
                         (list (regexp :tag "Server regexp")
                               (list (regexp :tag "Incoming Mailbox regexp")
                                     (repeat :tag "Rules for matching server(s) and mailbox(es)"
                                             (list (string :tag "Destination mailbox")
                                                   (choice :tag "Predicate"
                                                           (regexp :tag "A Regexp")
                                                           (nnimap-strict-function :tag "A Function")))))))))

(defcustom nnimap-split-predicate "UNSEEN UNDELETED"
  "The predicate used to find articles to split.
If you use another IMAP client to peek on articles but always would
like nnimap to split them once it's started, you could change this to
\"UNDELETED\". Other available predicates are available in
RFC2060 section 6.4.4."
  :group 'nnimap
  :type 'string)

(defcustom nnimap-split-fancy nil
  "Like the variable `nnmail-split-fancy', which see."
  :group 'nnimap
  :type 'sexp)

(defcustom nnimap-split-download-body nil
  "Whether to download entire articles during splitting.
This is generally not required, and will slow things down considerably.
You may need it if you want to use an advanced splitting function that
analyses the body before splitting the article."
  :group 'nnimap
  :type 'boolean)

;; Performance / bug workaround variables

(defcustom nnimap-close-asynchronous t
  "Close mailboxes asynchronously in `nnimap-close-group'.
This means that errors cought by nnimap when closing the mailbox will
not prevent Gnus from updating the group status, which may be harmful.
However, it increases speed."
  :type 'boolean
  :group 'nnimap)

(defcustom nnimap-dont-close t
  "Never close mailboxes.
This increases the speed of closing mailboxes (quiting group) but may
decrease the speed of selecting another mailbox later.  Re-selecting
the same mailbox will be faster though."
  :type 'boolean
  :group 'nnimap)

(defcustom nnimap-retrieve-groups-asynchronous t
  "Send asynchronous STATUS commands for each mailbox before checking mail.
If you have mailboxes that rarely receives mail, this speeds up new
mail checking.  It works by first sending STATUS commands for each
mailbox, and then only checking groups which has a modified UIDNEXT
more carefully for new mail.

In summary, the default is O((1-p)*k+p*n) and changing it to nil makes
it O(n).  If p is small, then the default is probably faster."
  :type 'boolean
  :group 'nnimap)

(defvoo nnimap-need-unselect-to-notice-new-mail nil
  "Unselect mailboxes before looking for new mail in them.
Some servers seem to need this under some circumstances.")

;; Authorization / Privacy variables

(defvoo nnimap-auth-method nil
  "Obsolete.")

(defvoo nnimap-stream nil
  "How nnimap will connect to the server.

The default, nil, will try to use the \"best\" method the server can
handle.

Change this if

1) you want to connect with SSL.  The SSL integration with IMAP is
   brain-dead so you'll have to tell it specifically.

2) your server is more capable than your environment -- i.e. your
   server accept Kerberos login's but you haven't installed the
   `imtest' program or your machine isn't configured for Kerberos.

Possible choices: kerberos4, ssl, network")

(defvoo nnimap-authenticator nil
  "How nnimap authenticate itself to the server.

The default, nil, will try to use the \"best\" method the server can
handle.

There is only one reason for fiddling with this variable, and that is
if your server is more capable than your environment -- i.e. you
connect to a server that accept Kerberos login's but you haven't
installed the `imtest' program or your machine isn't configured for
Kerberos.

Possible choices: kerberos4, cram-md5, login, anonymous.")

(defvoo nnimap-directory (nnheader-concat gnus-directory "overview/")
  "Directory to keep NOV cache files for nnimap groups.
See also `nnimap-nov-file-name'.")

(defvoo nnimap-nov-file-name "nnimap."
  "NOV cache base filename.
The group name and `nnimap-nov-file-name-suffix' will be appended.  A
typical complete file name would be
~/News/overview/nnimap.pdc.INBOX.ding.nov, or
~/News/overview/nnimap/pdc/INBOX/ding/nov if
`nnmail-use-long-file-names' is nil")

(defvoo nnimap-nov-file-name-suffix ".novcache"
  "Suffix for NOV cache base filename.")

(defvoo nnimap-nov-is-evil gnus-agent
  "If non-nil, never generate or use a local nov database for this backend.
Using nov databases should speed up header fetching considerably.
However, it will invoke a UID SEARCH UID command on the server, and
some servers implement this command inefficiently by opening each and
every message in the group, thus making it quite slow.
Unlike other backends, you do not need to take special care if you
flip this variable.")

(defvoo nnimap-expunge-on-close 'always ; 'ask, 'never
  "Whether to expunge a group when it is closed.
When a IMAP group with articles marked for deletion is closed, this
variable determine if nnimap should actually remove the articles or
not.

If always, nnimap always perform a expunge when closing the group.
If never, nnimap never expunges articles marked for deletion.
If ask, nnimap will ask you if you wish to expunge marked articles.

When setting this variable to `never', you can only expunge articles
by using `G x' (gnus-group-nnimap-expunge) from the Group buffer.")

(defvoo nnimap-list-pattern "*"
  "A string LIMIT or list of strings with mailbox wildcards used to limit available groups.
See below for available wildcards.