1 ;;; gnus-nocem.el --- NoCeM pseudo-cancellation treatment
2 ;; Copyright (C) 1995,96,97,98,99 Free Software Foundation, Inc.
4 ;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
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!
54 "*List of NoCeM issuers to pay attention to.
56 This can also be a list of `(ISSUER CONDITIONS)' elements."
58 :type '(repeat (choice string sexp)))
60 (defcustom gnus-nocem-directory
61 (nnheader-concat gnus-article-save-directory "NoCeM/")
62 "*Directory where NoCeM files will be stored."
66 (defcustom gnus-nocem-expiry-wait 15
67 "*Number of days to keep NoCeM headers in the cache."
71 (defcustom gnus-nocem-verifyer 'mc-verify
72 "*Function called to verify that the NoCeM message is valid.
73 One likely value is `mc-verify'. If the function in this variable
74 isn't bound, the message will be used unconditionally."
76 :type '(radio (function-item mc-verify)
77 (function :tag "other")))
79 (defcustom gnus-nocem-liberal-fetch nil
80 "*If t try to fetch all messages which have @@NCM in the subject.
81 Otherwise don't fetch messages which have references or whose message-id
82 matches an previously scanned and verified nocem message."
86 ;;; Internal variables
88 (defvar gnus-nocem-active nil)
89 (defvar gnus-nocem-alist nil)
90 (defvar gnus-nocem-touched-alist nil)
91 (defvar gnus-nocem-hashtb nil)
92 (defvar gnus-nocem-seen-message-ids nil)
96 (defun gnus-nocem-active-file ()
97 (concat (file-name-as-directory gnus-nocem-directory) "active"))
99 (defun gnus-nocem-cache-file ()
100 (concat (file-name-as-directory gnus-nocem-directory) "cache"))
103 ;; faster lookups for group names:
106 (defvar gnus-nocem-real-group-hashtb nil
107 "Real-name mappings of subscribed groups.")
109 (defun gnus-fill-real-hashtb ()
110 "Fill up a hash table with the real-name mappings from the user's active file."
111 (setq gnus-nocem-real-group-hashtb (gnus-make-hashtable
112 (length gnus-newsrc-alist)))
113 (mapcar (lambda (group)
114 (setq group (gnus-group-real-name (car group)))
115 (gnus-sethash group t gnus-nocem-real-group-hashtb))
118 (defun gnus-nocem-scan-groups ()
119 "Scan all NoCeM groups for new NoCeM messages."
121 (let ((groups gnus-nocem-groups)
122 (gnus-inhibit-demon t)
123 group active gactive articles check-headers)
124 (gnus-make-directory gnus-nocem-directory)
125 ;; Load any previous NoCeM headers.
126 (gnus-nocem-load-cache)
127 ;; Get the group name mappings:
128 (gnus-fill-real-hashtb)
129 ;; Read the active file if it hasn't been read yet.
130 (and (file-exists-p (gnus-nocem-active-file))
131 (not gnus-nocem-active)
133 (load (gnus-nocem-active-file) t t t)))
134 ;; Go through all groups and see whether new articles have
136 (while (setq group (pop groups))
137 (if (not (setq gactive (gnus-activate-group group)))
138 () ; This group doesn't exist.
139 (setq active (nth 1 (assoc group gnus-nocem-active)))
140 (when (and (not (< (cdr gactive) (car gactive))) ; Empty group.
142 (< (cdr active) (cdr gactive))))
143 ;; Ok, there are new articles in this group, se we fetch the
146 (let ((dependencies (make-vector 10 nil))
151 (gnus-retrieve-headers
153 (gnus-uncompress-range
155 (if active (1+ (cdr active))
159 (gnus-get-newsgroup-headers-xover
160 articles nil dependencies)
161 (gnus-get-newsgroup-headers dependencies)))
162 (while (setq header (pop headers))
163 ;; We take a closer look on all articles that have
164 ;; "@@NCM" in the subject. Unless we already read
165 ;; this cross posted message. Nocem messages
166 ;; are not allowed to have references, so we can
167 ;; ignore scanning followups.
168 (and (string-match "@@NCM" (mail-header-subject header))
169 (or gnus-nocem-liberal-fetch
170 (and (or (string= "" (mail-header-references
172 (null (mail-header-references header)))
173 (not (member (mail-header-message-id header)
174 gnus-nocem-seen-message-ids))))
175 (push header check-headers)))
177 (len (length check-headers)))
178 (dolist (h check-headers)
180 7 "Checking article %d in %s for NoCeM (%d of %d)..."
181 (mail-header-number h) group (incf i) len)
182 (gnus-nocem-check-article group h)))))))
183 (setq gnus-nocem-active
184 (cons (list group gactive)
185 (delq (assoc group gnus-nocem-active)
186 gnus-nocem-active)))))
187 ;; Save the results, if any.
188 (gnus-nocem-save-cache)
189 (gnus-nocem-save-active)))
191 (defun gnus-nocem-check-article (group header)
192 "Check whether the current article is an NCM article and that we want it."
194 (let ((date (mail-header-date header))
198 (time-since (date-to-time date))
199 (days-to-time gnus-nocem-expiry-wait)))
200 (gnus-request-article-this-buffer (mail-header-number header) group)
201 (goto-char (point-min))
202 (when (re-search-forward "-----BEGIN PGP MESSAGE-----" nil t)
203 (delete-region (point-min) (match-beginning 0)))
204 (when (re-search-forward "-----END PGP MESSAGE-----\n?" nil t)
205 (delete-region (match-end 0) (point-max)))
206 (goto-char (point-min))
207 ;; The article has to have proper NoCeM headers.
208 (when (and (setq b (search-forward "\n@@BEGIN NCM HEADERS\n" nil t))
209 (setq e (search-forward "\n@@BEGIN NCM BODY\n" nil t)))
210 ;; We get the name of the issuer.
211 (narrow-to-region b e)
212 (setq issuer (mail-fetch-field "issuer")
213 type (mail-fetch-field "issuer"))
215 (if (not (gnus-nocem-message-wanted-p issuer type))
216 (message "invalid NoCeM issuer: %s" issuer)
217 (and (gnus-nocem-verify-issuer issuer) ; She is who she says she is.
218 (gnus-nocem-enter-article) ; We gobble the message.
219 (push (mail-header-message-id header) ; But don't come back for
220 gnus-nocem-seen-message-ids))))))) ; second helpings.
222 (defun gnus-nocem-message-wanted-p (issuer type)
223 (let ((issuers gnus-nocem-issuers)
224 wanted conditions condition)
226 ;; Do the quick check first.
227 ((member issuer issuers)
229 ((setq conditions (cdr (assoc issuer issuers)))
230 ;; Check whether we want this type.
231 (while (setq condition (pop conditions))
234 (setq wanted (string-match condition type)))
235 ((and (consp condition)
236 (eq (car condition) 'not)
237 (stringp (cadr condition)))
238 (setq wanted (not (string-match (cadr condition) type))))
240 (error "Invalid NoCeM condition: %S" condition))))
243 (defun gnus-nocem-verify-issuer (person)
244 "Verify using PGP that the canceler is who she says she is."
245 (if (fboundp gnus-nocem-verifyer)
247 (funcall gnus-nocem-verifyer))
248 ;; If we don't have Mailcrypt, then we use the message anyway.
251 (defun gnus-nocem-enter-article ()
252 "Enter the current article into the NoCeM cache."
253 (goto-char (point-min))
254 (let ((b (search-forward "\n@@BEGIN NCM BODY\n" nil t))
255 (e (search-forward "\n@@END NCM BODY\n" nil t))
256 (buf (current-buffer))
259 (narrow-to-region b (1+ (match-beginning 0)))
260 (goto-char (point-min))
261 (while (search-forward "\t" nil t)
264 (setq group (let ((obarray gnus-active-hashtb)) (read buf)))))
267 ((not (symbolp group))
268 ;; Ignore invalid entries.
270 ((not (boundp group))
271 ;; Make sure all entries in the hashtb are bound.
274 (when (gnus-gethash (gnus-group-real-name (symbol-name group))
275 gnus-nocem-real-group-hashtb)
278 (while (eq (char-after) ?\t)
280 (setq id (buffer-substring (point) (1- (search-forward "\t"))))
281 (unless (gnus-gethash id gnus-nocem-hashtb)
282 ;; only store if not already present
283 (gnus-sethash id t gnus-nocem-hashtb)
286 (while (eq (char-after) ?\t)
287 (forward-line 1))))))
289 (setq gnus-nocem-touched-alist t)
290 (push (cons (let ((time (current-time))) (setcdr (cdr time) nil) time)
295 (defun gnus-nocem-load-cache ()
296 "Load the NoCeM cache."
298 (unless gnus-nocem-alist
299 ;; The buffer doesn't exist, so we create it and load the NoCeM
301 (when (file-exists-p (gnus-nocem-cache-file))
302 (load (gnus-nocem-cache-file) t t t)
303 (gnus-nocem-alist-to-hashtb))))
305 (defun gnus-nocem-save-cache ()
306 "Save the NoCeM cache."
307 (when (and gnus-nocem-alist
308 gnus-nocem-touched-alist)
309 (with-temp-file (gnus-nocem-cache-file)
310 (gnus-prin1 `(setq gnus-nocem-alist ',gnus-nocem-alist)))
311 (setq gnus-nocem-touched-alist nil)))
313 (defun gnus-nocem-save-active ()
314 "Save the NoCeM active file."
315 (with-temp-file (gnus-nocem-active-file)
316 (gnus-prin1 `(setq gnus-nocem-active ',gnus-nocem-active))))
318 (defun gnus-nocem-alist-to-hashtb ()
319 "Create a hashtable from the Message-IDs we have."
320 (let* ((alist gnus-nocem-alist)
321 (pprev (cons nil alist))
323 (expiry (days-to-time gnus-nocem-expiry-wait))
325 (setq gnus-nocem-hashtb (gnus-make-hashtable (* (length alist) 51)))
326 (while (setq entry (car alist))
327 (if (not (time-less-p (time-since (car entry)) expiry))
328 ;; This entry has expired, so we remove it.
329 (setcdr prev (cdr alist))
331 ;; This is ok, so we enter it into the hashtable.
332 (setq entry (cdr entry))
334 (gnus-sethash (car entry) t gnus-nocem-hashtb)
335 (setq entry (cdr entry))))
336 (setq alist (cdr alist)))))
338 (gnus-add-shutdown 'gnus-nocem-close 'gnus)
340 (defun gnus-nocem-close ()
341 "Clear internal NoCeM variables."
342 (setq gnus-nocem-alist nil
343 gnus-nocem-hashtb nil
344 gnus-nocem-active nil
345 gnus-nocem-touched-alist nil
346 gnus-nocem-seen-message-ids nil
347 gnus-nocem-real-group-hashtb nil))
349 (defun gnus-nocem-unwanted-article-p (id)
350 "Say whether article ID in the current group is wanted."
351 (and gnus-nocem-hashtb
352 (gnus-gethash id gnus-nocem-hashtb)))
354 (provide 'gnus-nocem)
356 ;;; gnus-nocem.el ends here