1 ;;; gnus-nocem.el --- NoCeM pseudo-cancellation treatment
3 ;; Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000 Free Software Foundation, Inc.
5 ;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
8 ;; This file is part of GNU Emacs.
10 ;; GNU Emacs is free software; you can redistribute it and/or modify
11 ;; it under the terms of the GNU General Public License as published by
12 ;; the Free Software Foundation; either version 2, or (at your option)
15 ;; GNU Emacs is distributed in the hope that it will be useful,
16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 ;; GNU General Public License for more details.
20 ;; You should have received a copy of the GNU General Public License
21 ;; along with GNU Emacs; see the file COPYING. If not, write to the
22 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
23 ;; Boston, MA 02111-1307, USA.
29 (eval-when-compile (require 'cl))
30 (eval-when-compile (require 'gnus-clfns))
38 (defgroup gnus-nocem nil
39 "NoCeM pseudo-cancellation treatment"
42 (defcustom gnus-nocem-groups
43 '("news.lists.filters" "news.admin.net-abuse.bulletins"
44 "alt.nocem.misc" "news.admin.net-abuse.announce")
45 "*List of groups that will be searched for NoCeM messages."
47 :type '(repeat (string :tag "Group")))
49 (defcustom gnus-nocem-issuers
50 '("AutoMoose-1" ; CancelMoose[tm]
51 "clewis@ferret.ocunix" ; Chris Lewis
55 "*List of NoCeM issuers to pay attention to.
57 This can also be a list of `(ISSUER CONDITION ...)' elements.
59 See <URL:http://www.xs4all.nl/~rosalind/nocemreg/nocemreg.html> for an
62 :type '(repeat (choice string sexp)))
64 (defcustom gnus-nocem-directory
65 (nnheader-concat gnus-article-save-directory "NoCeM/")
66 "*Directory where NoCeM files will be stored."
70 (defcustom gnus-nocem-expiry-wait 15
71 "*Number of days to keep NoCeM headers in the cache."
75 (defcustom gnus-nocem-verifyer 'mc-verify
76 "*Function called to verify that the NoCeM message is valid.
77 One likely value is `mc-verify'. If the function in this variable
78 isn't bound, the message will be used unconditionally."
80 :type '(radio (function-item mc-verify)
81 (function :tag "other")))
83 (defcustom gnus-nocem-liberal-fetch nil
84 "*If t try to fetch all messages which have @@NCM in the subject.
85 Otherwise don't fetch messages which have references or whose message-id
86 matches an previously scanned and verified nocem message."
90 (defcustom gnus-nocem-check-article-limit 500
91 "*If non-nil, the maximum number of articles to check in any NoCeM group."
94 :type '(choice (const :tag "unlimited" nil)
97 (defcustom gnus-nocem-check-from t
98 "Non-nil means check for valid issuers in message bodies.
99 Otherwise don't bother fetching articles unless their author matches a
100 valid issuer, which is much faster if you are selective about the issuers."
105 ;;; Internal variables
107 (defvar gnus-nocem-active nil)
108 (defvar gnus-nocem-alist nil)
109 (defvar gnus-nocem-touched-alist nil)
110 (defvar gnus-nocem-hashtb nil)
111 (defvar gnus-nocem-seen-message-ids nil)
115 (defun gnus-nocem-active-file ()
116 (concat (file-name-as-directory gnus-nocem-directory) "active"))
118 (defun gnus-nocem-cache-file ()
119 (concat (file-name-as-directory gnus-nocem-directory) "cache"))
122 ;; faster lookups for group names:
125 (defvar gnus-nocem-real-group-hashtb nil
126 "Real-name mappings of subscribed groups.")
128 (defun gnus-fill-real-hashtb ()
129 "Fill up a hash table with the real-name mappings from the user's active file."
130 (setq gnus-nocem-real-group-hashtb (gnus-make-hashtable
131 (length gnus-newsrc-alist)))
132 (mapcar (lambda (group)
133 (setq group (gnus-group-real-name (car group)))
134 (gnus-sethash group t gnus-nocem-real-group-hashtb))
137 (defun gnus-nocem-scan-groups ()
138 "Scan all NoCeM groups for new NoCeM messages."
140 (let ((groups gnus-nocem-groups)
141 (gnus-inhibit-demon t)
142 group active gactive articles check-headers)
143 (gnus-make-directory gnus-nocem-directory)
144 ;; Load any previous NoCeM headers.
145 (gnus-nocem-load-cache)
146 ;; Get the group name mappings:
147 (gnus-fill-real-hashtb)
148 ;; Read the active file if it hasn't been read yet.
149 (and (file-exists-p (gnus-nocem-active-file))
150 (not gnus-nocem-active)
152 (load (gnus-nocem-active-file) t t t)))
153 ;; Go through all groups and see whether new articles have
155 (while (setq group (pop groups))
156 (if (not (setq gactive (gnus-activate-group group)))
157 () ; This group doesn't exist.
158 (setq active (nth 1 (assoc group gnus-nocem-active)))
159 (when (and (not (< (cdr gactive) (car gactive))) ; Empty group.
161 (< (cdr active) (cdr gactive))))
162 ;; Ok, there are new articles in this group, se we fetch the
165 (let ((dependencies (make-vector 10 nil))
170 (gnus-retrieve-headers
172 (gnus-uncompress-range
174 (if active (1+ (cdr active))
178 (gnus-get-newsgroup-headers-xover
179 articles nil dependencies)
180 (gnus-get-newsgroup-headers dependencies)))
181 (while (setq header (pop headers))
182 ;; We take a closer look on all articles that have
183 ;; "@@NCM" in the subject. Unless we already read
184 ;; this cross posted message. Nocem messages
185 ;; are not allowed to have references, so we can
186 ;; ignore scanning followups.
187 (and (string-match "@@NCM" (mail-header-subject header))
188 (and gnus-nocem-check-from
189 (let ((case-fold-search t))
194 (setq author (car author)))
196 author (mail-header-from header))
200 (or gnus-nocem-liberal-fetch
201 (and (or (string= "" (mail-header-references
203 (null (mail-header-references header)))
204 (not (member (mail-header-message-id header)
205 gnus-nocem-seen-message-ids))))
206 (push header check-headers)))
209 (last check-headers gnus-nocem-check-article-limit))
210 (len (length check-headers)))
211 (dolist (h check-headers)
213 7 "Checking article %d in %s for NoCeM (%d of %d)..."
214 (mail-header-number h) group (incf i) len)
215 (gnus-nocem-check-article group h)))))))
216 (setq gnus-nocem-active
217 (cons (list group gactive)
218 (delq (assoc group gnus-nocem-active)
219 gnus-nocem-active)))))
220 ;; Save the results, if any.
221 (gnus-nocem-save-cache)
222 (gnus-nocem-save-active)))
224 (defun gnus-nocem-check-article (group header)
225 "Check whether the current article is an NCM article and that we want it."
227 (let ((date (mail-header-date header))
228 (gnus-newsgroup-name group)
232 (time-since (date-to-time date))
233 (days-to-time gnus-nocem-expiry-wait)))
234 (gnus-request-article-this-buffer (mail-header-number header) group)
235 (goto-char (point-min))
236 (when (re-search-forward "-----BEGIN PGP MESSAGE-----" nil t)
237 (delete-region (point-min) (match-beginning 0)))
238 (when (re-search-forward "-----END PGP MESSAGE-----\n?" nil t)
239 (delete-region (match-end 0) (point-max)))
240 (goto-char (point-min))
241 ;; The article has to have proper NoCeM headers.
242 (when (and (setq b (search-forward "\n@@BEGIN NCM HEADERS\n" nil t))
243 (setq e (search-forward "\n@@BEGIN NCM BODY\n" nil t)))
244 ;; We get the name of the issuer.
245 (narrow-to-region b e)
246 (setq issuer (mail-fetch-field "issuer")
247 type (mail-fetch-field "issuer"))
249 (if (not (gnus-nocem-message-wanted-p issuer type))
250 (message "invalid NoCeM issuer: %s" issuer)
251 (and (gnus-nocem-verify-issuer issuer) ; She is who she says she is.
252 (gnus-nocem-enter-article) ; We gobble the message.
253 (push (mail-header-message-id header) ; But don't come back for
254 gnus-nocem-seen-message-ids))))))) ; second helpings.
256 (defun gnus-nocem-message-wanted-p (issuer type)
257 (let ((issuers gnus-nocem-issuers)
258 wanted conditions condition)
260 ;; Do the quick check first.
261 ((member issuer issuers)
263 ((setq conditions (cdr (assoc issuer issuers)))
264 ;; Check whether we want this type.
265 (while (setq condition (pop conditions))
268 (setq wanted (string-match condition type)))
269 ((and (consp condition)
270 (eq (car condition) 'not)
271 (stringp (cadr condition)))
272 (setq wanted (not (string-match (cadr condition) type))))
274 (error "Invalid NoCeM condition: %S" condition))))
277 (defun gnus-nocem-verify-issuer (person)
278 "Verify using PGP that the canceler is who she says she is."
279 (if (fboundp gnus-nocem-verifyer)
281 (funcall gnus-nocem-verifyer))
282 ;; If we don't have Mailcrypt, then we use the message anyway.
285 (defun gnus-nocem-enter-article ()
286 "Enter the current article into the NoCeM cache."
287 (goto-char (point-min))
288 (let ((b (search-forward "\n@@BEGIN NCM BODY\n" nil t))
289 (e (search-forward "\n@@END NCM BODY\n" nil t))
290 (buf (current-buffer))
293 (narrow-to-region b (1+ (match-beginning 0)))
294 (goto-char (point-min))
295 (while (search-forward "\t" nil t)
298 (setq group (let ((obarray gnus-active-hashtb)) (read buf)))))
301 ((not (symbolp group))
302 ;; Ignore invalid entries.
304 ((not (boundp group))
305 ;; Make sure all entries in the hashtb are bound.
308 (when (gnus-gethash (gnus-group-real-name (symbol-name group))
309 gnus-nocem-real-group-hashtb)
312 (while (eq (char-after) ?\t)
314 (setq id (buffer-substring (point) (1- (search-forward "\t"))))
315 (unless (gnus-gethash id gnus-nocem-hashtb)
316 ;; only store if not already present
317 (gnus-sethash id t gnus-nocem-hashtb)
320 (while (eq (char-after) ?\t)
321 (forward-line 1))))))
323 (setq gnus-nocem-touched-alist t)
324 (push (cons (let ((time (current-time))) (setcdr (cdr time) nil) time)
329 (defun gnus-nocem-load-cache ()
330 "Load the NoCeM cache."
332 (unless gnus-nocem-alist
333 ;; The buffer doesn't exist, so we create it and load the NoCeM
335 (when (file-exists-p (gnus-nocem-cache-file))
336 (load (gnus-nocem-cache-file) t t t)
337 (gnus-nocem-alist-to-hashtb))))
339 (defun gnus-nocem-save-cache ()
340 "Save the NoCeM cache."
341 (when (and gnus-nocem-alist
342 gnus-nocem-touched-alist)
343 (with-temp-file (gnus-nocem-cache-file)
344 (gnus-prin1 `(setq gnus-nocem-alist ',gnus-nocem-alist)))
345 (setq gnus-nocem-touched-alist nil)))
347 (defun gnus-nocem-save-active ()
348 "Save the NoCeM active file."
349 (with-temp-file (gnus-nocem-active-file)
350 (gnus-prin1 `(setq gnus-nocem-active ',gnus-nocem-active))))
352 (defun gnus-nocem-alist-to-hashtb ()
353 "Create a hashtable from the Message-IDs we have."
354 (let* ((alist gnus-nocem-alist)
355 (pprev (cons nil alist))
357 (expiry (days-to-time gnus-nocem-expiry-wait))
359 (setq gnus-nocem-hashtb (gnus-make-hashtable (* (length alist) 51)))
360 (while (setq entry (car alist))
361 (if (not (time-less-p (time-since (car entry)) expiry))
362 ;; This entry has expired, so we remove it.
363 (setcdr prev (cdr alist))
365 ;; This is ok, so we enter it into the hashtable.
366 (setq entry (cdr entry))
368 (gnus-sethash (car entry) t gnus-nocem-hashtb)
369 (setq entry (cdr entry))))
370 (setq alist (cdr alist)))))
372 (gnus-add-shutdown 'gnus-nocem-close 'gnus)
374 (defun gnus-nocem-close ()
375 "Clear internal NoCeM variables."
376 (setq gnus-nocem-alist nil
377 gnus-nocem-hashtb nil
378 gnus-nocem-active nil
379 gnus-nocem-touched-alist nil
380 gnus-nocem-seen-message-ids nil
381 gnus-nocem-real-group-hashtb nil))
383 (defun gnus-nocem-unwanted-article-p (id)
384 "Say whether article ID in the current group is wanted."
385 (and gnus-nocem-hashtb
386 (gnus-gethash id gnus-nocem-hashtb)))
388 (provide 'gnus-nocem)
390 ;;; gnus-nocem.el ends here