1 ;;; gnus-nocem.el --- NoCeM pseudo-cancellation treatment
3 ;; Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
4 ;; 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
6 ;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
9 ;; This file is part of GNU Emacs.
11 ;; GNU Emacs is free software: you can redistribute it and/or modify
12 ;; it under the terms of the GNU General Public License as published by
13 ;; the Free Software Foundation, either version 3 of the License, or
14 ;; (at your option) any later version.
16 ;; GNU Emacs is distributed in the hope that it will be useful,
17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 ;; GNU General Public License for more details.
21 ;; You should have received a copy of the GNU General Public License
22 ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
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" "alt.nocem.misc")
42 "*List of groups that will be searched for NoCeM messages."
45 :type '(repeat (string :tag "Group")))
47 (defcustom gnus-nocem-issuers
49 "alba-nocem@albasani.net"
50 "bleachbot@httrack.com"
51 "news@arcor-online.net"
54 "pgpmoose@killfile.org"
56 "*List of NoCeM issuers to pay attention to.
58 This can also be a list of `(ISSUER CONDITION ...)' elements.
60 See <URL:http://www.xs4all.nl/~rosalind/nocemreg/nocemreg.html> for an
63 :link '(url-link "http://www.xs4all.nl/~rosalind/nocemreg/nocemreg.html")
65 :type '(repeat (cons :format "%v" (string :tag "Issuer")
66 (repeat :tag "Condition"
67 (group (checklist :inline t (const not))
68 (regexp :tag "Type" :value ".*")))))
70 (mapcar (lambda (elem)
74 (if (consp elt) elt (list elt)))
77 (default-value symbol)))
78 :set (lambda (symbol value)
81 (mapcar (lambda (elem)
86 (if (cdr elt) elt (car elt))
93 (defcustom gnus-nocem-directory
94 (nnheader-concat gnus-article-save-directory "NoCeM/")
95 "*Directory where NoCeM files will be stored."
99 (defcustom gnus-nocem-expiry-wait 15
100 "*Number of days to keep NoCeM headers in the cache."
104 (defcustom gnus-nocem-verifyer (if (locate-library "epg")
105 'gnus-nocem-epg-verify
107 "*Function called to verify that the NoCeM message is valid.
108 If the function in this variable isn't bound, the message will be used
112 :type '(radio (function-item gnus-nocem-epg-verify)
113 (function-item pgg-verify)
114 (function-item mc-verify)
115 (function :tag "other"))
116 :set (lambda (symbol value)
117 (custom-set-default symbol
118 (if (and (eq value 'gnus-nocem-epg-verify)
119 (not (locate-library "epg")))
123 (defcustom gnus-nocem-liberal-fetch nil
124 "*If t try to fetch all messages which have @@NCM in the subject.
125 Otherwise don't fetch messages which have references or whose message-id
126 matches a previously scanned and verified nocem message."
130 (defcustom gnus-nocem-check-article-limit 500
131 "*If non-nil, the maximum number of articles to check in any NoCeM group."
134 :type '(choice (const :tag "unlimited" nil)
137 (defcustom gnus-nocem-check-from t
138 "Non-nil means check for valid issuers in message bodies.
139 Otherwise don't bother fetching articles unless their author matches a
140 valid issuer, which is much faster if you are selective about the issuers."
145 ;;; Internal variables
147 (defvar gnus-nocem-active nil)
148 (defvar gnus-nocem-alist nil)
149 (defvar gnus-nocem-touched-alist nil)
150 (defvar gnus-nocem-hashtb nil)
151 (defvar gnus-nocem-seen-message-ids nil)
155 (defun gnus-nocem-active-file ()
156 (concat (file-name-as-directory gnus-nocem-directory) "active"))
158 (defun gnus-nocem-cache-file ()
159 (concat (file-name-as-directory gnus-nocem-directory) "cache"))
162 ;; faster lookups for group names:
165 (defvar gnus-nocem-real-group-hashtb nil
166 "Real-name mappings of subscribed groups.")
168 (defun gnus-fill-real-hashtb ()
169 "Fill up a hash table with the real-name mappings from the user's active file."
170 (if (hash-table-p gnus-nocem-real-group-hashtb)
171 (clrhash gnus-nocem-real-group-hashtb)
172 (setq gnus-nocem-real-group-hashtb (make-hash-table :test 'equal)))
173 (mapcar (lambda (group)
174 (setq group (gnus-group-real-name (car group)))
175 (puthash group t gnus-nocem-real-group-hashtb))
179 (defun gnus-nocem-scan-groups ()
180 "Scan all NoCeM groups for new NoCeM messages."
182 (let ((groups gnus-nocem-groups)
183 (gnus-inhibit-demon t)
184 group active gactive articles check-headers)
185 (gnus-make-directory gnus-nocem-directory)
186 ;; Load any previous NoCeM headers.
187 (gnus-nocem-load-cache)
188 ;; Get the group name mappings:
189 (gnus-fill-real-hashtb)
190 ;; Read the active file if it hasn't been read yet.
191 (and (file-exists-p (gnus-nocem-active-file))
192 (not gnus-nocem-active)
194 (load (gnus-nocem-active-file) t t t)))
195 ;; Go through all groups and see whether new articles have
197 (while (setq group (pop groups))
198 (if (not (setq gactive (gnus-activate-group group)))
199 () ; This group doesn't exist.
200 (setq active (nth 1 (assoc group gnus-nocem-active)))
201 (when (and (not (< (cdr gactive) (car gactive))) ; Empty group.
203 (< (cdr active) (cdr gactive))))
204 ;; Ok, there are new articles in this group, se we fetch the
207 (let ((dependencies (make-vector 10 nil))
212 (gnus-retrieve-headers
214 (gnus-uncompress-range
216 (if active (1+ (cdr active))
220 (gnus-get-newsgroup-headers-xover
221 articles nil dependencies)
222 (gnus-get-newsgroup-headers dependencies)))
223 (while (setq header (pop headers))
224 ;; We take a closer look on all articles that have
225 ;; "@@NCM" in the subject. Unless we already read
226 ;; this cross posted message. Nocem messages
227 ;; are not allowed to have references, so we can
228 ;; ignore scanning followups.
229 (and (string-match "@@NCM" (mail-header-subject header))
230 (and gnus-nocem-check-from
231 (let ((case-fold-search t))
236 (setq author (car author)))
238 author (mail-header-from header))
242 (or gnus-nocem-liberal-fetch
243 (and (or (string= "" (mail-header-references
245 (null (mail-header-references header)))
246 (not (member (mail-header-message-id header)
247 gnus-nocem-seen-message-ids))))
248 (push header check-headers)))
249 (setq check-headers (last (nreverse check-headers)
250 gnus-nocem-check-article-limit))
252 (len (length check-headers)))
253 (dolist (h check-headers)
255 7 "Checking article %d in %s for NoCeM (%d of %d)..."
256 (mail-header-number h) group (incf i) len)
257 (gnus-nocem-check-article group h)))))))
258 (setq gnus-nocem-active
259 (cons (list group gactive)
260 (delq (assoc group gnus-nocem-active)
261 gnus-nocem-active)))))
262 ;; Save the results, if any.
263 (gnus-nocem-save-cache)
264 (gnus-nocem-save-active)))
266 (defun gnus-nocem-check-article (group header)
267 "Check whether the current article is an NCM article and that we want it."
269 (let ((date (mail-header-date header))
270 (gnus-newsgroup-name group)
274 (time-since (date-to-time date))
275 (days-to-time gnus-nocem-expiry-wait)))
276 (gnus-request-article-this-buffer (mail-header-number header) group)
277 (goto-char (point-min))
278 (when (re-search-forward
279 "-----BEGIN PGP\\(?: SIGNED\\)? MESSAGE-----"
281 (delete-region (point-min) (match-beginning 0)))
282 (when (re-search-forward
283 "-----END PGP \\(?:MESSAGE\\|SIGNATURE\\)-----\n?"
285 (delete-region (match-end 0) (point-max)))
286 (goto-char (point-min))
287 ;; The article has to have proper NoCeM headers.
288 (when (and (setq b (search-forward "\n@@BEGIN NCM HEADERS\n" nil t))
289 (setq e (search-forward "\n@@BEGIN NCM BODY\n" nil t)))
290 ;; We get the name of the issuer.
291 (narrow-to-region b e)
292 (setq issuer (mail-fetch-field "issuer")
293 type (mail-fetch-field "type"))
295 (if (not (gnus-nocem-message-wanted-p issuer type))
296 (message "invalid NoCeM issuer: %s" issuer)
297 (and (gnus-nocem-verify-issuer issuer) ; She is who she says she is.
298 (gnus-nocem-enter-article) ; We gobble the message.
299 (push (mail-header-message-id header) ; But don't come back for
300 gnus-nocem-seen-message-ids))))))) ; second helpings.
302 (defun gnus-nocem-message-wanted-p (issuer type)
303 (let ((issuers gnus-nocem-issuers)
304 wanted conditions condition)
306 ;; Do the quick check first.
307 ((member issuer issuers)
309 ((setq conditions (cdr (assoc issuer issuers)))
310 ;; Check whether we want this type.
311 (while (setq condition (pop conditions))
314 (when (string-match condition type)
316 ((and (consp condition)
317 (eq (car condition) 'not)
318 (stringp (cadr condition)))
319 (when (string-match (cadr condition) type)
322 (error "Invalid NoCeM condition: %S" condition))))
325 (defun gnus-nocem-verify-issuer (person)
326 "Verify using PGP that the canceler is who she says she is."
327 (if (functionp gnus-nocem-verifyer)
329 (funcall gnus-nocem-verifyer))
330 ;; If we don't have Mailcrypt, then we use the message anyway.
333 (defun gnus-nocem-enter-article ()
334 "Enter the current article into the NoCeM cache."
335 (goto-char (point-min))
336 (let ((b (search-forward "\n@@BEGIN NCM BODY\n" nil t))
337 (e (search-forward "\n@@END NCM BODY\n" nil t))
338 (buf (current-buffer))
341 (narrow-to-region b (1+ (match-beginning 0)))
342 (goto-char (point-min))
343 (while (search-forward "\t" nil t)
346 (setq group (gnus-group-real-name (symbol-name (read buf))))
347 (gethash group gnus-nocem-real-group-hashtb)))
353 (while (eq (char-after) ?\t)
355 (setq id (buffer-substring (point) (1- (search-forward "\t"))))
356 (unless (if (hash-table-p gnus-nocem-hashtb)
357 (gethash id gnus-nocem-hashtb)
358 (setq gnus-nocem-hashtb (make-hash-table :test 'equal))
360 ;; only store if not already present
361 (puthash id t gnus-nocem-hashtb)
364 (while (eq (char-after) ?\t)
367 (setq gnus-nocem-touched-alist t)
368 (push (cons (let ((time (current-time))) (setcdr (cdr time) nil) time)
374 (defun gnus-nocem-load-cache ()
375 "Load the NoCeM cache."
377 (unless gnus-nocem-alist
378 ;; The buffer doesn't exist, so we create it and load the NoCeM
380 (when (file-exists-p (gnus-nocem-cache-file))
381 (load (gnus-nocem-cache-file) t t t)
382 (gnus-nocem-alist-to-hashtb))))
384 (defun gnus-nocem-save-cache ()
385 "Save the NoCeM cache."
386 (when (and gnus-nocem-alist
387 gnus-nocem-touched-alist)
388 (with-temp-file (gnus-nocem-cache-file)
389 (gnus-prin1 `(setq gnus-nocem-alist ',gnus-nocem-alist)))
390 (setq gnus-nocem-touched-alist nil)))
392 (defun gnus-nocem-save-active ()
393 "Save the NoCeM active file."
394 (with-temp-file (gnus-nocem-active-file)
395 (gnus-prin1 `(setq gnus-nocem-active ',gnus-nocem-active))))
397 (defun gnus-nocem-alist-to-hashtb ()
398 "Create a hashtable from the Message-IDs we have."
399 (let* ((alist gnus-nocem-alist)
400 (pprev (cons nil alist))
402 (expiry (days-to-time gnus-nocem-expiry-wait))
404 (if (hash-table-p gnus-nocem-hashtb)
405 (clrhash gnus-nocem-hashtb)
406 (setq gnus-nocem-hashtb (make-hash-table :test 'equal)))
407 (while (setq entry (car alist))
408 (if (not (time-less-p (time-since (car entry)) expiry))
409 ;; This entry has expired, so we remove it.
410 (setcdr prev (cdr alist))
412 ;; This is ok, so we enter it into the hashtable.
413 (setq entry (cdr entry))
415 (puthash (car entry) t gnus-nocem-hashtb)
416 (setq entry (cdr entry))))
417 (setq alist (cdr alist)))))
419 (gnus-add-shutdown 'gnus-nocem-close 'gnus)
421 (defun gnus-nocem-close ()
422 "Clear internal NoCeM variables."
423 (setq gnus-nocem-alist nil
424 gnus-nocem-hashtb nil
425 gnus-nocem-active nil
426 gnus-nocem-touched-alist nil
427 gnus-nocem-seen-message-ids nil
428 gnus-nocem-real-group-hashtb nil))
430 (defun gnus-nocem-unwanted-article-p (id)
431 "Say whether article ID in the current group is wanted."
432 (and gnus-nocem-hashtb
433 (gethash id gnus-nocem-hashtb)))
435 (autoload 'epg-make-context "epg")
437 (autoload 'epg-verify-string "epg")
438 (autoload 'epg-context-result-for "epg")
439 (autoload 'epg-signature-status "epg"))
441 (defun gnus-nocem-epg-verify ()
442 "Return t if EasyPG verifies a signed message in the current buffer."
443 (let ((context (epg-make-context 'OpenPGP))
445 (epg-verify-string context (buffer-string))
446 (and (setq result (epg-context-result-for context 'verify))
448 (eq (epg-signature-status (car result)) 'good))))
450 (provide 'gnus-nocem)
452 ;; arch-tag: 0e0c74ea-2f8e-4f3e-8fff-09f767c1adef
453 ;;; gnus-nocem.el ends here