1 ;;; gnus-nocem.el --- NoCeM pseudo-cancellation treatment
2 ;; Copyright (C) 1995,96 Free Software Foundation, Inc.
4 ;; Author: Lars Magne Ingebrigtsen <larsi@ifi.uio.no>
7 ;; This file is part of GNU Emacs.
9 ;; GNU Emacs is free software; you can redistribute it and/or modify
10 ;; it under the terms of the GNU General Public License as published by
11 ;; the Free Software Foundation; either version 2, or (at your option)
14 ;; GNU Emacs is distributed in the hope that it will be useful,
15 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
16 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 ;; GNU General Public License for more details.
19 ;; You should have received a copy of the GNU General Public License
20 ;; along with GNU Emacs; see the file COPYING. If not, write to the
21 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
22 ;; Boston, MA 02111-1307, USA.
33 (defvar gnus-nocem-groups
34 '("alt.nocem.misc" "news.admin.net-abuse.announce")
35 "*List of groups that will be searched for NoCeM messages.")
37 (defvar gnus-nocem-issuers
38 '("Automoose-1" ; The CancelMoose[tm] on autopilot.
39 "clewis@ferret.ocunix.on.ca;" ; Chris Lewis -- Canadian angel & despammer.
40 "jem@xpat.com;" ; John Milburn -- despammer in Korea.
41 "red@redpoll.mrfs.oh.us (Richard E. Depew)" ; Spew/bincancel guy.
43 "*List of NoCeM issuers to pay attention to.")
45 (defvar gnus-nocem-directory
46 (concat (file-name-as-directory gnus-article-save-directory) "NoCeM/")
47 "*Directory where NoCeM files will be stored.")
49 (defvar gnus-nocem-expiry-wait 15
50 "*Number of days to keep NoCeM headers in the cache.")
52 (defvar gnus-nocem-verifyer nil
53 "*Function called to verify that the NoCeM message is valid.
54 One likely value is `mc-verify'. If the function in this variable
55 isn't bound, the message will be used unconditionally.")
57 ;;; Internal variables
59 (defvar gnus-nocem-active nil)
60 (defvar gnus-nocem-alist nil)
61 (defvar gnus-nocem-touched-alist nil)
62 (defvar gnus-nocem-hashtb nil)
66 (defun gnus-nocem-active-file ()
67 (concat (file-name-as-directory gnus-nocem-directory) "active"))
69 (defun gnus-nocem-cache-file ()
70 (concat (file-name-as-directory gnus-nocem-directory) "cache"))
72 (defun gnus-nocem-scan-groups ()
73 "Scan all NoCeM groups for new NoCeM messages."
75 (let ((groups gnus-nocem-groups)
76 group active gactive articles)
77 (or (file-exists-p gnus-nocem-directory)
78 (make-directory gnus-nocem-directory t))
79 ;; Load any previous NoCeM headers.
80 (gnus-nocem-load-cache)
81 ;; Read the active file if it hasn't been read yet.
82 (and (file-exists-p (gnus-nocem-active-file))
83 (not gnus-nocem-active)
85 (load (gnus-nocem-active-file) t t t)
87 ;; Go through all groups and see whether new articles have
89 (while (setq group (pop groups))
90 (if (not (setq gactive (gnus-activate-group group)))
91 () ; This group doesn't exist.
92 (setq active (nth 1 (assoc group gnus-nocem-active)))
93 (when (and (not (< (cdr gactive) (car gactive))) ; Empty group.
95 (< (cdr active) (cdr gactive))))
96 ;; Ok, there are new articles in this group, se we fetch the
99 (let ((dependencies (make-vector 10 nil))
100 (buffer (nnheader-set-temp-buffer " *Gnus NoCeM*"))
104 (gnus-retrieve-headers
106 (gnus-uncompress-range
108 (if active (1+ (cdr active))
112 (gnus-get-newsgroup-headers-xover
113 articles nil dependencies)
114 (gnus-get-newsgroup-headers dependencies)))
116 ;; We take a closer look on all articles that have
117 ;; "@@NCM" in the subject.
118 (when (string-match "@@NCM"
119 (mail-header-subject (car headers)))
120 (gnus-nocem-check-article group (car headers)))
121 (setq headers (cdr headers)))
122 (kill-buffer (current-buffer)))))
123 (setq gnus-nocem-active
124 (cons (list group gactive)
125 (delq (assoc group gnus-nocem-active)
126 gnus-nocem-active)))))
127 ;; Save the results, if any.
128 (gnus-nocem-save-cache)
129 (gnus-nocem-save-active)))
131 (defun gnus-nocem-check-article (group header)
132 "Check whether the current article is an NCM article and that we want it."
134 (gnus-message 7 "Checking article %d in %s for NoCeM..."
135 (mail-header-number header) group)
136 (let ((date (mail-header-date header))
140 (nnmail-time-since (nnmail-date-to-time date))
141 (nnmail-days-to-time gnus-nocem-expiry-wait)))
142 (gnus-request-article-this-buffer (mail-header-number header) group)
143 (goto-char (point-min))
144 ;; The article has to have proper NoCeM headers.
145 (when (and (setq b (search-forward "\n@@BEGIN NCM HEADERS\n" nil t))
146 (setq e (search-forward "\n@@BEGIN NCM BODY\n" nil t)))
147 ;; We get the name of the issuer.
148 (narrow-to-region b e)
149 (setq issuer (mail-fetch-field "issuer"))
150 (and (member issuer gnus-nocem-issuers) ; We like her...
151 (gnus-nocem-verify-issuer issuer) ; She is who she says she is..
152 (gnus-nocem-enter-article)))))) ; We gobble the message.
154 (defun gnus-nocem-verify-issuer (person)
155 "Verify using PGP that the canceler is who she says she is."
157 (if (fboundp gnus-nocem-verifyer)
158 (funcall gnus-nocem-verifyer)
159 ;; If we don't have MailCrypt, then we use the message anyway.
162 (defun gnus-nocem-enter-article ()
163 "Enter the current article into the NoCeM cache."
164 (goto-char (point-min))
165 (let ((b (search-forward "\n@@BEGIN NCM BODY\n" nil t))
166 (e (search-forward "\n@@END NCM BODY\n" nil t))
167 (buf (current-buffer))
170 (narrow-to-region b (1+ (match-beginning 0)))
171 (goto-char (point-min))
172 (while (search-forward "\t" nil t)
173 (when (condition-case nil
174 (boundp (let ((obarray gnus-active-hashtb)) (read buf)))
177 (while (= (following-char) ?\t)
179 (setq id (buffer-substring (point) (1- (search-forward "\t"))))
181 (gnus-sethash id t gnus-nocem-hashtb)
183 (while (= (following-char) ?\t)
186 (setq gnus-nocem-touched-alist t)
187 (push (cons (let ((time (current-time))) (setcdr (cdr time) nil) time)
189 gnus-nocem-alist)))))
191 (defun gnus-nocem-load-cache ()
192 "Load the NoCeM cache."
193 (unless gnus-nocem-alist
194 ;; The buffer doesn't exist, so we create it and load the NoCeM
196 (when (file-exists-p (gnus-nocem-cache-file))
197 (load (gnus-nocem-cache-file) t t t)
198 (gnus-nocem-alist-to-hashtb))))
200 (defun gnus-nocem-save-cache ()
201 "Save the NoCeM cache."
202 (when (and gnus-nocem-alist
203 gnus-nocem-touched-alist)
204 (nnheader-temp-write (gnus-nocem-cache-file)
205 (prin1 `(setq gnus-nocem-alist ',gnus-nocem-alist) (current-buffer)))
206 (setq gnus-nocem-touched-alist nil)))
208 (defun gnus-nocem-save-active ()
209 "Save the NoCeM active file."
210 (nnheader-temp-write (gnus-nocem-active-file)
211 (prin1 `(setq gnus-nocem-active ',gnus-nocem-active) (current-buffer))))
213 (defun gnus-nocem-alist-to-hashtb ()
214 "Create a hashtable from the Message-IDs we have."
215 (let* ((alist gnus-nocem-alist)
216 (pprev (cons nil alist))
218 (expiry (nnmail-days-to-time gnus-nocem-expiry-wait))
220 (setq gnus-nocem-hashtb (gnus-make-hashtable (* (length alist) 51)))
221 (while (setq entry (car alist))
222 (if (not (nnmail-time-less (nnmail-time-since (car entry)) expiry))
223 ;; This entry has expired, so we remove it.
224 (setcdr prev (cdr alist))
226 ;; This is ok, so we enter it into the hashtable.
227 (setq entry (cdr entry))
229 (gnus-sethash (car entry) t gnus-nocem-hashtb)
230 (setq entry (cdr entry))))
231 (setq alist (cdr alist)))))
233 (gnus-add-shutdown 'gnus-nocem-close 'gnus)
235 (defun gnus-nocem-close ()
236 "Clear internal NoCeM variables."
237 (setq gnus-nocem-alist nil
238 gnus-nocem-hashtb nil
239 gnus-nocem-active nil
240 gnus-nocem-touched-alist nil))
242 (defun gnus-nocem-unwanted-article-p (id)
243 "Say whether article ID in the current group is wanted."
244 (gnus-gethash id gnus-nocem-hashtb))
246 (provide 'gnus-nocem)
248 ;;; gnus-nocem.el ends here