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[emacs.git] / lisp / gnus / gnus-nocem.el
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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>
6 ;; Keywords: news
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)
13 ;; any later version.
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.
25 ;;; Commentary:
27 ;;; Code:
29 (eval-when-compile (require 'cl))
31 (require 'gnus)
32 (require 'nnmail)
33 (require 'gnus-art)
34 (require 'gnus-sum)
35 (require 'gnus-range)
37 (defgroup gnus-nocem nil
38 "NoCeM pseudo-cancellation treatment"
39 :group 'gnus-score)
41 (defcustom gnus-nocem-groups
42 '("news.lists.filters" "news.admin.net-abuse.bulletins"
43 "alt.nocem.misc" "news.admin.net-abuse.announce")
44 "*List of groups that will be searched for NoCeM messages."
45 :group 'gnus-nocem
46 :type '(repeat (string :tag "Group")))
48 (defcustom gnus-nocem-issuers
49 '("AutoMoose-1" ; CancelMoose[tm]
50 "clewis@ferret.ocunix" ; Chris Lewis
51 "cosmo.roadkill"
52 "SpamHippo"
53 "hweede@snafu.de")
54 "*List of NoCeM issuers to pay attention to.
56 This can also be a list of `(ISSUER CONDITION ...)' elements.
58 See <URL:http://www.xs4all.nl/~rosalind/nocemreg/nocemreg.html> for an
59 issuer registry."
60 :group 'gnus-nocem
61 :type '(repeat (choice string sexp)))
63 (defcustom gnus-nocem-directory
64 (nnheader-concat gnus-article-save-directory "NoCeM/")
65 "*Directory where NoCeM files will be stored."
66 :group 'gnus-nocem
67 :type 'directory)
69 (defcustom gnus-nocem-expiry-wait 15
70 "*Number of days to keep NoCeM headers in the cache."
71 :group 'gnus-nocem
72 :type 'integer)
74 (defcustom gnus-nocem-verifyer 'mc-verify
75 "*Function called to verify that the NoCeM message is valid.
76 One likely value is `mc-verify'. If the function in this variable
77 isn't bound, the message will be used unconditionally."
78 :group 'gnus-nocem
79 :type '(radio (function-item mc-verify)
80 (function :tag "other")))
82 (defcustom gnus-nocem-liberal-fetch nil
83 "*If t try to fetch all messages which have @@NCM in the subject.
84 Otherwise don't fetch messages which have references or whose message-id
85 matches a previously scanned and verified nocem message."
86 :group 'gnus-nocem
87 :type 'boolean)
89 (defcustom gnus-nocem-check-article-limit 500
90 "*If non-nil, the maximum number of articles to check in any NoCeM group."
91 :group 'gnus-nocem
92 :version "21.1"
93 :type '(choice (const :tag "unlimited" nil)
94 (integer 1000)))
96 (defcustom gnus-nocem-check-from t
97 "Non-nil means check for valid issuers in message bodies.
98 Otherwise don't bother fetching articles unless their author matches a
99 valid issuer, which is much faster if you are selective about the issuers."
100 :group 'gnus-nocem
101 :version "21.1"
102 :type 'boolean)
104 ;;; Internal variables
106 (defvar gnus-nocem-active nil)
107 (defvar gnus-nocem-alist nil)
108 (defvar gnus-nocem-touched-alist nil)
109 (defvar gnus-nocem-hashtb nil)
110 (defvar gnus-nocem-seen-message-ids nil)
112 ;;; Functions
114 (defun gnus-nocem-active-file ()
115 (concat (file-name-as-directory gnus-nocem-directory) "active"))
117 (defun gnus-nocem-cache-file ()
118 (concat (file-name-as-directory gnus-nocem-directory) "cache"))
121 ;; faster lookups for group names:
124 (defvar gnus-nocem-real-group-hashtb nil
125 "Real-name mappings of subscribed groups.")
127 (defun gnus-fill-real-hashtb ()
128 "Fill up a hash table with the real-name mappings from the user's active file."
129 (setq gnus-nocem-real-group-hashtb (gnus-make-hashtable
130 (length gnus-newsrc-alist)))
131 (mapcar (lambda (group)
132 (setq group (gnus-group-real-name (car group)))
133 (gnus-sethash group t gnus-nocem-real-group-hashtb))
134 gnus-newsrc-alist))
136 (defun gnus-nocem-scan-groups ()
137 "Scan all NoCeM groups for new NoCeM messages."
138 (interactive)
139 (let ((groups gnus-nocem-groups)
140 (gnus-inhibit-demon t)
141 group active gactive articles check-headers)
142 (gnus-make-directory gnus-nocem-directory)
143 ;; Load any previous NoCeM headers.
144 (gnus-nocem-load-cache)
145 ;; Get the group name mappings:
146 (gnus-fill-real-hashtb)
147 ;; Read the active file if it hasn't been read yet.
148 (and (file-exists-p (gnus-nocem-active-file))
149 (not gnus-nocem-active)
150 (ignore-errors
151 (load (gnus-nocem-active-file) t t t)))
152 ;; Go through all groups and see whether new articles have
153 ;; arrived.
154 (while (setq group (pop groups))
155 (if (not (setq gactive (gnus-activate-group group)))
156 () ; This group doesn't exist.
157 (setq active (nth 1 (assoc group gnus-nocem-active)))
158 (when (and (not (< (cdr gactive) (car gactive))) ; Empty group.
159 (or (not active)
160 (< (cdr active) (cdr gactive))))
161 ;; Ok, there are new articles in this group, se we fetch the
162 ;; headers.
163 (save-excursion
164 (let ((dependencies (make-vector 10 nil))
165 headers header)
166 (with-temp-buffer
167 (setq headers
168 (if (eq 'nov
169 (gnus-retrieve-headers
170 (setq articles
171 (gnus-uncompress-range
172 (cons
173 (if active (1+ (cdr active))
174 (car gactive))
175 (cdr gactive))))
176 group))
177 (gnus-get-newsgroup-headers-xover
178 articles nil dependencies)
179 (gnus-get-newsgroup-headers dependencies)))
180 (while (setq header (pop headers))
181 ;; We take a closer look on all articles that have
182 ;; "@@NCM" in the subject. Unless we already read
183 ;; this cross posted message. Nocem messages
184 ;; are not allowed to have references, so we can
185 ;; ignore scanning followups.
186 (and (string-match "@@NCM" (mail-header-subject header))
187 (and gnus-nocem-check-from
188 (let ((case-fold-search t))
189 (catch 'ok
190 (mapcar
191 (lambda (author)
192 (if (consp author)
193 (setq author (car author)))
194 (if (string-match
195 author (mail-header-from header))
196 (throw 'ok t)))
197 gnus-nocem-issuers)
198 nil)))
199 (or gnus-nocem-liberal-fetch
200 (and (or (string= "" (mail-header-references
201 header))
202 (null (mail-header-references header)))
203 (not (member (mail-header-message-id header)
204 gnus-nocem-seen-message-ids))))
205 (push header check-headers)))
206 (let* ((i 0)
207 (check-headers
208 (last check-headers gnus-nocem-check-article-limit))
209 (len (length check-headers)))
210 (dolist (h check-headers)
211 (gnus-message
212 7 "Checking article %d in %s for NoCeM (%d of %d)..."
213 (mail-header-number h) group (incf i) len)
214 (gnus-nocem-check-article group h)))))))
215 (setq gnus-nocem-active
216 (cons (list group gactive)
217 (delq (assoc group gnus-nocem-active)
218 gnus-nocem-active)))))
219 ;; Save the results, if any.
220 (gnus-nocem-save-cache)
221 (gnus-nocem-save-active)))
223 (defun gnus-nocem-check-article (group header)
224 "Check whether the current article is an NCM article and that we want it."
225 ;; Get the article.
226 (let ((date (mail-header-date header))
227 (gnus-newsgroup-name group)
228 issuer b e type)
229 (when (or (not date)
230 (time-less-p
231 (time-since (date-to-time date))
232 (days-to-time gnus-nocem-expiry-wait)))
233 (gnus-request-article-this-buffer (mail-header-number header) group)
234 (goto-char (point-min))
235 (when (re-search-forward "-----BEGIN PGP MESSAGE-----" nil t)
236 (delete-region (point-min) (match-beginning 0)))
237 (when (re-search-forward "-----END PGP MESSAGE-----\n?" nil t)
238 (delete-region (match-end 0) (point-max)))
239 (goto-char (point-min))
240 ;; The article has to have proper NoCeM headers.
241 (when (and (setq b (search-forward "\n@@BEGIN NCM HEADERS\n" nil t))
242 (setq e (search-forward "\n@@BEGIN NCM BODY\n" nil t)))
243 ;; We get the name of the issuer.
244 (narrow-to-region b e)
245 (setq issuer (mail-fetch-field "issuer")
246 type (mail-fetch-field "issuer"))
247 (widen)
248 (if (not (gnus-nocem-message-wanted-p issuer type))
249 (message "invalid NoCeM issuer: %s" issuer)
250 (and (gnus-nocem-verify-issuer issuer) ; She is who she says she is.
251 (gnus-nocem-enter-article) ; We gobble the message.
252 (push (mail-header-message-id header) ; But don't come back for
253 gnus-nocem-seen-message-ids))))))) ; second helpings.
255 (defun gnus-nocem-message-wanted-p (issuer type)
256 (let ((issuers gnus-nocem-issuers)
257 wanted conditions condition)
258 (cond
259 ;; Do the quick check first.
260 ((member issuer issuers)
262 ((setq conditions (cdr (assoc issuer issuers)))
263 ;; Check whether we want this type.
264 (while (setq condition (pop conditions))
265 (cond
266 ((stringp condition)
267 (setq wanted (string-match condition type)))
268 ((and (consp condition)
269 (eq (car condition) 'not)
270 (stringp (cadr condition)))
271 (setq wanted (not (string-match (cadr condition) type))))
273 (error "Invalid NoCeM condition: %S" condition))))
274 wanted))))
276 (defun gnus-nocem-verify-issuer (person)
277 "Verify using PGP that the canceler is who she says she is."
278 (if (fboundp gnus-nocem-verifyer)
279 (ignore-errors
280 (funcall gnus-nocem-verifyer))
281 ;; If we don't have Mailcrypt, then we use the message anyway.
284 (defun gnus-nocem-enter-article ()
285 "Enter the current article into the NoCeM cache."
286 (goto-char (point-min))
287 (let ((b (search-forward "\n@@BEGIN NCM BODY\n" nil t))
288 (e (search-forward "\n@@END NCM BODY\n" nil t))
289 (buf (current-buffer))
290 ncm id group)
291 (when (and b e)
292 (narrow-to-region b (1+ (match-beginning 0)))
293 (goto-char (point-min))
294 (while (search-forward "\t" nil t)
295 (cond
296 ((not (ignore-errors
297 (setq group (let ((obarray gnus-active-hashtb)) (read buf)))))
298 ;; An error.
300 ((not (symbolp group))
301 ;; Ignore invalid entries.
303 ((not (boundp group))
304 ;; Make sure all entries in the hashtb are bound.
305 (set group nil))
307 (when (gnus-gethash (gnus-group-real-name (symbol-name group))
308 gnus-nocem-real-group-hashtb)
309 ;; Valid group.
310 (beginning-of-line)
311 (while (eq (char-after) ?\t)
312 (forward-line -1))
313 (setq id (buffer-substring (point) (1- (search-forward "\t"))))
314 (unless (gnus-gethash id gnus-nocem-hashtb)
315 ;; only store if not already present
316 (gnus-sethash id t gnus-nocem-hashtb)
317 (push id ncm))
318 (forward-line 1)
319 (while (eq (char-after) ?\t)
320 (forward-line 1))))))
321 (when ncm
322 (setq gnus-nocem-touched-alist t)
323 (push (cons (let ((time (current-time))) (setcdr (cdr time) nil) time)
324 ncm)
325 gnus-nocem-alist))
326 t)))
328 (defun gnus-nocem-load-cache ()
329 "Load the NoCeM cache."
330 (interactive)
331 (unless gnus-nocem-alist
332 ;; The buffer doesn't exist, so we create it and load the NoCeM
333 ;; cache.
334 (when (file-exists-p (gnus-nocem-cache-file))
335 (load (gnus-nocem-cache-file) t t t)
336 (gnus-nocem-alist-to-hashtb))))
338 (defun gnus-nocem-save-cache ()
339 "Save the NoCeM cache."
340 (when (and gnus-nocem-alist
341 gnus-nocem-touched-alist)
342 (with-temp-file (gnus-nocem-cache-file)
343 (gnus-prin1 `(setq gnus-nocem-alist ',gnus-nocem-alist)))
344 (setq gnus-nocem-touched-alist nil)))
346 (defun gnus-nocem-save-active ()
347 "Save the NoCeM active file."
348 (with-temp-file (gnus-nocem-active-file)
349 (gnus-prin1 `(setq gnus-nocem-active ',gnus-nocem-active))))
351 (defun gnus-nocem-alist-to-hashtb ()
352 "Create a hashtable from the Message-IDs we have."
353 (let* ((alist gnus-nocem-alist)
354 (pprev (cons nil alist))
355 (prev pprev)
356 (expiry (days-to-time gnus-nocem-expiry-wait))
357 entry)
358 (setq gnus-nocem-hashtb (gnus-make-hashtable (* (length alist) 51)))
359 (while (setq entry (car alist))
360 (if (not (time-less-p (time-since (car entry)) expiry))
361 ;; This entry has expired, so we remove it.
362 (setcdr prev (cdr alist))
363 (setq prev alist)
364 ;; This is ok, so we enter it into the hashtable.
365 (setq entry (cdr entry))
366 (while entry
367 (gnus-sethash (car entry) t gnus-nocem-hashtb)
368 (setq entry (cdr entry))))
369 (setq alist (cdr alist)))))
371 (gnus-add-shutdown 'gnus-nocem-close 'gnus)
373 (defun gnus-nocem-close ()
374 "Clear internal NoCeM variables."
375 (setq gnus-nocem-alist nil
376 gnus-nocem-hashtb nil
377 gnus-nocem-active nil
378 gnus-nocem-touched-alist nil
379 gnus-nocem-seen-message-ids nil
380 gnus-nocem-real-group-hashtb nil))
382 (defun gnus-nocem-unwanted-article-p (id)
383 "Say whether article ID in the current group is wanted."
384 (and gnus-nocem-hashtb
385 (gnus-gethash id gnus-nocem-hashtb)))
387 (provide 'gnus-nocem)
389 ;;; gnus-nocem.el ends here