1 ;;; gnus-nocem.el --- NoCeM pseudo-cancellation treatment
2 ;; Copyright (C) 1995,96,97,98 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.
28 (eval-when-compile (require 'cl))
36 (defgroup gnus-nocem nil
37 "NoCeM pseudo-cancellation treatment"
40 (defcustom gnus-nocem-groups
41 '("news.lists.filters" "news.admin.net-abuse.bulletins"
42 "alt.nocem.misc" "news.admin.net-abuse.announce")
43 "*List of groups that will be searched for NoCeM messages."
45 :type '(repeat (string :tag "Group")))
47 (defcustom gnus-nocem-issuers
48 '("AutoMoose-1" "Automoose-1" ; CancelMoose[tm]
49 "rbraver@ohww.norman.ok.us" ; Robert Braver
50 "clewis@ferret.ocunix.on.ca" ; Chris Lewis
51 "jem@xpat.com" ; Despammer from Korea
52 "snowhare@xmission.com" ; Benjamin "Snowhare" Franz
53 "red@redpoll.mrfs.oh.us (Richard E. Depew)" ; ARMM! ARMM!
55 "*List of NoCeM issuers to pay attention to.
57 This can also be a list of `(ISSUER CONDITIONS)' elements."
59 :type '(repeat (choice string sexp)))
61 (defcustom gnus-nocem-directory
62 (nnheader-concat gnus-article-save-directory "NoCeM/")
63 "*Directory where NoCeM files will be stored."
67 (defcustom gnus-nocem-expiry-wait 15
68 "*Number of days to keep NoCeM headers in the cache."
72 (defcustom gnus-nocem-verifyer 'mc-verify
73 "*Function called to verify that the NoCeM message is valid.
74 One likely value is `mc-verify'. If the function in this variable
75 isn't bound, the message will be used unconditionally."
77 :type '(radio (function-item mc-verify)
78 (function :tag "other")))
80 (defcustom gnus-nocem-liberal-fetch nil
81 "*If t try to fetch all messages which have @@NCM in the subject.
82 Otherwise don't fetch messages which have references or whose message-id
83 matches an previously scanned and verified nocem message."
87 ;;; Internal variables
89 (defvar gnus-nocem-active nil)
90 (defvar gnus-nocem-alist nil)
91 (defvar gnus-nocem-touched-alist nil)
92 (defvar gnus-nocem-hashtb nil)
93 (defvar gnus-nocem-seen-message-ids nil)
97 (defun gnus-nocem-active-file ()
98 (concat (file-name-as-directory gnus-nocem-directory) "active"))
100 (defun gnus-nocem-cache-file ()
101 (concat (file-name-as-directory gnus-nocem-directory) "cache"))
104 ;; faster lookups for group names:
107 (defvar gnus-nocem-real-group-hashtb nil
108 "Real-name mappings of subscribed groups.")
110 (defun gnus-fill-real-hashtb ()
111 "Fill up a hash table with the real-name mappings from the user's
113 (setq gnus-nocem-real-group-hashtb (gnus-make-hashtable
114 (length gnus-newsrc-alist)))
115 (mapcar (lambda (group)
116 (setq group (gnus-group-real-name (car group)))
117 (gnus-sethash group t gnus-nocem-real-group-hashtb))
120 (defun gnus-nocem-scan-groups ()
121 "Scan all NoCeM groups for new NoCeM messages."
123 (let ((groups gnus-nocem-groups)
124 (gnus-inhibit-demon t)
125 group active gactive articles)
126 (gnus-make-directory gnus-nocem-directory)
127 ;; Load any previous NoCeM headers.
128 (gnus-nocem-load-cache)
129 ;; Get the group name mappings:
130 (gnus-fill-real-hashtb)
131 ;; Read the active file if it hasn't been read yet.
132 (and (file-exists-p (gnus-nocem-active-file))
133 (not gnus-nocem-active)
135 (load (gnus-nocem-active-file) t t t)))
136 ;; Go through all groups and see whether new articles have
138 (while (setq group (pop groups))
139 (if (not (setq gactive (gnus-activate-group group)))
140 () ; This group doesn't exist.
141 (setq active (nth 1 (assoc group gnus-nocem-active)))
142 (when (and (not (< (cdr gactive) (car gactive))) ; Empty group.
144 (< (cdr active) (cdr gactive))))
145 ;; Ok, there are new articles in this group, se we fetch the
148 (let ((dependencies (make-vector 10 nil))
150 (nnheader-temp-write nil
153 (gnus-retrieve-headers
155 (gnus-uncompress-range
157 (if active (1+ (cdr active))
161 (gnus-get-newsgroup-headers-xover
162 articles nil dependencies)
163 (gnus-get-newsgroup-headers dependencies)))
164 (while (setq header (pop headers))
165 ;; We take a closer look on all articles that have
166 ;; "@@NCM" in the subject. Unless we already read
167 ;; this cross posted message. Nocem messages
168 ;; are not allowed to have references, so we can
169 ;; ignore scanning followups.
170 (and (string-match "@@NCM" (mail-header-subject header))
171 (or gnus-nocem-liberal-fetch
172 (and (or (string= "" (mail-header-references
174 (null (mail-header-references header)))
175 (not (member (mail-header-message-id header)
176 gnus-nocem-seen-message-ids))))
177 (gnus-nocem-check-article group header)))))))
178 (setq gnus-nocem-active
179 (cons (list group gactive)
180 (delq (assoc group gnus-nocem-active)
181 gnus-nocem-active)))))
182 ;; Save the results, if any.
183 (gnus-nocem-save-cache)
184 (gnus-nocem-save-active)))
186 (defun gnus-nocem-check-article (group header)
187 "Check whether the current article is an NCM article and that we want it."
189 (gnus-message 7 "Checking article %d in %s for NoCeM..."
190 (mail-header-number header) group)
191 (let ((date (mail-header-date header))
195 (nnmail-time-since (nnmail-date-to-time date))
196 (nnmail-days-to-time gnus-nocem-expiry-wait)))
197 (gnus-request-article-this-buffer (mail-header-number header) group)
198 (goto-char (point-min))
199 (when (re-search-forward "-----BEGIN PGP MESSAGE-----" nil t)
200 (delete-region (point-min) (match-beginning 0)))
201 (when (re-search-forward "-----END PGP MESSAGE-----\n?" nil t)
202 (delete-region (match-end 0) (point-max)))
203 (goto-char (point-min))
204 ;; The article has to have proper NoCeM headers.
205 (when (and (setq b (search-forward "\n@@BEGIN NCM HEADERS\n" nil t))
206 (setq e (search-forward "\n@@BEGIN NCM BODY\n" nil t)))
207 ;; We get the name of the issuer.
208 (narrow-to-region b e)
209 (setq issuer (mail-fetch-field "issuer")
210 type (mail-fetch-field "issuer"))
212 (if (not (gnus-nocem-message-wanted-p issuer type))
213 (message "invalid NoCeM issuer: %s" issuer)
214 (and (gnus-nocem-verify-issuer issuer) ; She is who she says she is.
215 (gnus-nocem-enter-article) ; We gobble the message.
216 (push (mail-header-message-id header) ; But don't come back for
217 gnus-nocem-seen-message-ids))))))) ; second helpings.
219 (defun gnus-nocem-message-wanted-p (issuer type)
220 (let ((issuers gnus-nocem-issuers)
221 wanted conditions condition)
223 ;; Do the quick check first.
224 ((member issuer issuers)
226 ((setq conditions (cdr (assoc issuer issuers)))
227 ;; Check whether we want this type.
228 (while (setq condition (pop conditions))
231 (setq wanted (string-match condition type)))
232 ((and (consp condition)
233 (eq (car condition) 'not)
234 (stringp (cadr condition)))
235 (setq wanted (not (string-match (cadr condition) type))))
237 (error "Invalid NoCeM condition: %S" condition))))
240 (defun gnus-nocem-verify-issuer (person)
241 "Verify using PGP that the canceler is who she says she is."
242 (if (fboundp gnus-nocem-verifyer)
244 (funcall gnus-nocem-verifyer))
245 ;; If we don't have Mailcrypt, then we use the message anyway.
248 (defun gnus-nocem-enter-article ()
249 "Enter the current article into the NoCeM cache."
250 (goto-char (point-min))
251 (let ((b (search-forward "\n@@BEGIN NCM BODY\n" nil t))
252 (e (search-forward "\n@@END NCM BODY\n" nil t))
253 (buf (current-buffer))
256 (narrow-to-region b (1+ (match-beginning 0)))
257 (goto-char (point-min))
258 (while (search-forward "\t" nil t)
261 (setq group (let ((obarray gnus-active-hashtb)) (read buf)))))
264 ((not (symbolp group))
265 ;; Ignore invalid entries.
267 ((not (boundp group))
268 ;; Make sure all entries in the hashtb are bound.
271 (when (gnus-gethash (gnus-group-real-name (symbol-name group))
272 gnus-nocem-real-group-hashtb)
275 (while (= (following-char) ?\t)
277 (setq id (buffer-substring (point) (1- (search-forward "\t"))))
278 (unless (gnus-gethash id gnus-nocem-hashtb)
279 ;; only store if not already present
280 (gnus-sethash id t gnus-nocem-hashtb)
283 (while (= (following-char) ?\t)
284 (forward-line 1))))))
286 (setq gnus-nocem-touched-alist t)
287 (push (cons (let ((time (current-time))) (setcdr (cdr time) nil) time)
292 (defun gnus-nocem-load-cache ()
293 "Load the NoCeM cache."
295 (unless gnus-nocem-alist
296 ;; The buffer doesn't exist, so we create it and load the NoCeM
298 (when (file-exists-p (gnus-nocem-cache-file))
299 (load (gnus-nocem-cache-file) t t t)
300 (gnus-nocem-alist-to-hashtb))))
302 (defun gnus-nocem-save-cache ()
303 "Save the NoCeM cache."
304 (when (and gnus-nocem-alist
305 gnus-nocem-touched-alist)
306 (nnheader-temp-write (gnus-nocem-cache-file)
307 (gnus-prin1 `(setq gnus-nocem-alist ',gnus-nocem-alist)))
308 (setq gnus-nocem-touched-alist nil)))
310 (defun gnus-nocem-save-active ()
311 "Save the NoCeM active file."
312 (nnheader-temp-write (gnus-nocem-active-file)
313 (gnus-prin1 `(setq gnus-nocem-active ',gnus-nocem-active))))
315 (defun gnus-nocem-alist-to-hashtb ()
316 "Create a hashtable from the Message-IDs we have."
317 (let* ((alist gnus-nocem-alist)
318 (pprev (cons nil alist))
320 (expiry (nnmail-days-to-time gnus-nocem-expiry-wait))
322 (setq gnus-nocem-hashtb (gnus-make-hashtable (* (length alist) 51)))
323 (while (setq entry (car alist))
324 (if (not (nnmail-time-less (nnmail-time-since (car entry)) expiry))
325 ;; This entry has expired, so we remove it.
326 (setcdr prev (cdr alist))
328 ;; This is ok, so we enter it into the hashtable.
329 (setq entry (cdr entry))
331 (gnus-sethash (car entry) t gnus-nocem-hashtb)
332 (setq entry (cdr entry))))
333 (setq alist (cdr alist)))))
335 (gnus-add-shutdown 'gnus-nocem-close 'gnus)
337 (defun gnus-nocem-close ()
338 "Clear internal NoCeM variables."
339 (setq gnus-nocem-alist nil
340 gnus-nocem-hashtb nil
341 gnus-nocem-active nil
342 gnus-nocem-touched-alist nil
343 gnus-nocem-seen-message-ids nil
344 gnus-nocem-real-group-hashtb nil))
346 (defun gnus-nocem-unwanted-article-p (id)
347 "Say whether article ID in the current group is wanted."
348 (and gnus-nocem-hashtb
349 (gnus-gethash id gnus-nocem-hashtb)))
351 (provide 'gnus-nocem)
353 ;;; gnus-nocem.el ends here