1 ;;; gnus-nocem.el --- NoCeM pseudo-cancellation treatment
2 ;; Copyright (C) 1995,96 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.
33 (defvar gnus-nocem-groups
34 '("alt.nocem.misc" "news.admin.net-abuse.announce")
35 "*List of groups that will be searched for NoCeM messages.")
37 (defvar gnus-nocem-issuers
38 '("Automoose-1" ; The CancelMoose[tm] on autopilot.
39 "clewis@ferret.ocunix.on.ca;" ; Chris Lewis -- Canadian angel & despammer.
40 "jem@xpat.com;" ; John Milburn -- despammer in Korea.
41 "red@redpoll.mrfs.oh.us (Richard E. Depew)" ; Spew/bincancel guy.
43 "*List of NoCeM issuers to pay attention to.")
45 (defvar gnus-nocem-directory
46 (concat (file-name-as-directory gnus-article-save-directory) "NoCeM/")
47 "*Directory where NoCeM files will be stored.")
49 (defvar gnus-nocem-expiry-wait 15
50 "*Number of days to keep NoCeM headers in the cache.")
52 (defvar gnus-nocem-verifyer nil
53 "*Function called to verify that the NoCeM message is valid.
54 One likely value is `mc-verify'. If the function in this variable
55 isn't bound, the message will be used unconditionally.")
57 ;;; Internal variables
59 (defvar gnus-nocem-active nil)
60 (defvar gnus-nocem-alist nil)
61 (defvar gnus-nocem-touched-alist nil)
62 (defvar gnus-nocem-hashtb nil)
66 (defun gnus-nocem-active-file ()
67 (concat (file-name-as-directory gnus-nocem-directory) "active"))
69 (defun gnus-nocem-cache-file ()
70 (concat (file-name-as-directory gnus-nocem-directory) "cache"))
72 (defun gnus-nocem-scan-groups ()
73 "Scan all NoCeM groups for new NoCeM messages."
75 (let ((groups gnus-nocem-groups)
76 group active gactive articles)
77 (gnus-make-directory gnus-nocem-directory)
78 ;; Load any previous NoCeM headers.
79 (gnus-nocem-load-cache)
80 ;; Read the active file if it hasn't been read yet.
81 (and (file-exists-p (gnus-nocem-active-file))
82 (not gnus-nocem-active)
84 (load (gnus-nocem-active-file) t t t)
86 ;; Go through all groups and see whether new articles have
88 (while (setq group (pop groups))
89 (if (not (setq gactive (gnus-activate-group group)))
90 () ; This group doesn't exist.
91 (setq active (nth 1 (assoc group gnus-nocem-active)))
92 (when (and (not (< (cdr gactive) (car gactive))) ; Empty group.
94 (< (cdr active) (cdr gactive))))
95 ;; Ok, there are new articles in this group, se we fetch the
98 (let ((dependencies (make-vector 10 nil))
100 (nnheader-temp-write nil
103 (gnus-retrieve-headers
105 (gnus-uncompress-range
107 (if active (1+ (cdr active))
111 (gnus-get-newsgroup-headers-xover
112 articles nil dependencies)
113 (gnus-get-newsgroup-headers dependencies)))
115 ;; We take a closer look on all articles that have
116 ;; "@@NCM" in the subject.
117 (when (string-match "@@NCM"
118 (mail-header-subject (car headers)))
119 (gnus-nocem-check-article group (car headers)))
120 (setq headers (cdr headers)))))))
121 (setq gnus-nocem-active
122 (cons (list group gactive)
123 (delq (assoc group gnus-nocem-active)
124 gnus-nocem-active)))))
125 ;; Save the results, if any.
126 (gnus-nocem-save-cache)
127 (gnus-nocem-save-active)))
129 (defun gnus-nocem-check-article (group header)
130 "Check whether the current article is an NCM article and that we want it."
132 (gnus-message 7 "Checking article %d in %s for NoCeM..."
133 (mail-header-number header) group)
134 (let ((date (mail-header-date header))
138 (nnmail-time-since (nnmail-date-to-time date))
139 (nnmail-days-to-time gnus-nocem-expiry-wait)))
140 (gnus-request-article-this-buffer (mail-header-number header) group)
141 (goto-char (point-min))
142 ;; The article has to have proper NoCeM headers.
143 (when (and (setq b (search-forward "\n@@BEGIN NCM HEADERS\n" nil t))
144 (setq e (search-forward "\n@@BEGIN NCM BODY\n" nil t)))
145 ;; We get the name of the issuer.
146 (narrow-to-region b e)
147 (setq issuer (mail-fetch-field "issuer"))
148 (and (member issuer gnus-nocem-issuers) ; We like her...
149 (gnus-nocem-verify-issuer issuer) ; She is who she says she is..
150 (gnus-nocem-enter-article)))))) ; We gobble the message.
152 (defun gnus-nocem-verify-issuer (person)
153 "Verify using PGP that the canceler is who she says she is."
155 (if (fboundp gnus-nocem-verifyer)
156 (funcall gnus-nocem-verifyer)
157 ;; If we don't have Mailcrypt, then we use the message anyway.
160 (defun gnus-nocem-enter-article ()
161 "Enter the current article into the NoCeM cache."
162 (goto-char (point-min))
163 (let ((b (search-forward "\n@@BEGIN NCM BODY\n" nil t))
164 (e (search-forward "\n@@END NCM BODY\n" nil t))
165 (buf (current-buffer))
168 (narrow-to-region b (1+ (match-beginning 0)))
169 (goto-char (point-min))
170 (while (search-forward "\t" nil t)
171 (when (condition-case nil
172 (boundp (let ((obarray gnus-active-hashtb)) (read buf)))
175 (while (= (following-char) ?\t)
177 (setq id (buffer-substring (point) (1- (search-forward "\t"))))
179 (gnus-sethash id t gnus-nocem-hashtb)
181 (while (= (following-char) ?\t)
184 (setq gnus-nocem-touched-alist t)
185 (push (cons (let ((time (current-time))) (setcdr (cdr time) nil) time)
187 gnus-nocem-alist)))))
189 (defun gnus-nocem-load-cache ()
190 "Load the NoCeM cache."
191 (unless gnus-nocem-alist
192 ;; The buffer doesn't exist, so we create it and load the NoCeM
194 (when (file-exists-p (gnus-nocem-cache-file))
195 (load (gnus-nocem-cache-file) t t t)
196 (gnus-nocem-alist-to-hashtb))))
198 (defun gnus-nocem-save-cache ()
199 "Save the NoCeM cache."
200 (when (and gnus-nocem-alist
201 gnus-nocem-touched-alist)
202 (nnheader-temp-write (gnus-nocem-cache-file)
203 (gnus-prin1 `(setq gnus-nocem-alist ',gnus-nocem-alist)))
204 (setq gnus-nocem-touched-alist nil)))
206 (defun gnus-nocem-save-active ()
207 "Save the NoCeM active file."
208 (nnheader-temp-write (gnus-nocem-active-file)
209 (gnus-prin1 `(setq gnus-nocem-active ',gnus-nocem-active))))
211 (defun gnus-nocem-alist-to-hashtb ()
212 "Create a hashtable from the Message-IDs we have."
213 (let* ((alist gnus-nocem-alist)
214 (pprev (cons nil alist))
216 (expiry (nnmail-days-to-time gnus-nocem-expiry-wait))
218 (setq gnus-nocem-hashtb (gnus-make-hashtable (* (length alist) 51)))
219 (while (setq entry (car alist))
220 (if (not (nnmail-time-less (nnmail-time-since (car entry)) expiry))
221 ;; This entry has expired, so we remove it.
222 (setcdr prev (cdr alist))
224 ;; This is ok, so we enter it into the hashtable.
225 (setq entry (cdr entry))
227 (gnus-sethash (car entry) t gnus-nocem-hashtb)
228 (setq entry (cdr entry))))
229 (setq alist (cdr alist)))))
231 (gnus-add-shutdown 'gnus-nocem-close 'gnus)
233 (defun gnus-nocem-close ()
234 "Clear internal NoCeM variables."
235 (setq gnus-nocem-alist nil
236 gnus-nocem-hashtb nil
237 gnus-nocem-active nil
238 gnus-nocem-touched-alist nil))
240 (defun gnus-nocem-unwanted-article-p (id)
241 "Say whether article ID in the current group is wanted."
242 (gnus-gethash id gnus-nocem-hashtb))
244 (provide 'gnus-nocem)
246 ;;; gnus-nocem.el ends here