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emacs/lisp/gnus-nocem.el
Lars Magne Ingebrigtsen c4c7f54c6a Synched with Gnus 5.2.31.
1996-06-29 00:29:17 +00:00

248 lines
8.4 KiB
EmacsLisp

;;; gnus-nocem.el --- NoCeM pseudo-cancellation treatment
;; Copyright (C) 1995,96 Free Software Foundation, Inc.
;; Author: Lars Magne Ingebrigtsen <larsi@ifi.uio.no>
;; Keywords: news
;; This file is part of GNU Emacs.
;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.
;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING. If not, write to the
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.
;;; Commentary:
;;; Code:
(require 'gnus)
(require 'nnmail)
(eval-when-compile (require 'cl))
(defvar gnus-nocem-groups
'("alt.nocem.misc" "news.admin.net-abuse.announce")
"*List of groups that will be searched for NoCeM messages.")
(defvar gnus-nocem-issuers
'("Automoose-1" ; The CancelMoose[tm] on autopilot.
"clewis@ferret.ocunix.on.ca;" ; Chris Lewis -- Canadian angel & despammer.
"jem@xpat.com;" ; John Milburn -- despammer in Korea.
"red@redpoll.mrfs.oh.us (Richard E. Depew)" ; Spew/bincancel guy.
)
"*List of NoCeM issuers to pay attention to.")
(defvar gnus-nocem-directory
(concat (file-name-as-directory gnus-article-save-directory) "NoCeM/")
"*Directory where NoCeM files will be stored.")
(defvar gnus-nocem-expiry-wait 15
"*Number of days to keep NoCeM headers in the cache.")
(defvar gnus-nocem-verifyer nil
"*Function called to verify that the NoCeM message is valid.
One likely value is `mc-verify'. If the function in this variable
isn't bound, the message will be used unconditionally.")
;;; Internal variables
(defvar gnus-nocem-active nil)
(defvar gnus-nocem-alist nil)
(defvar gnus-nocem-touched-alist nil)
(defvar gnus-nocem-hashtb nil)
;;; Functions
(defun gnus-nocem-active-file ()
(concat (file-name-as-directory gnus-nocem-directory) "active"))
(defun gnus-nocem-cache-file ()
(concat (file-name-as-directory gnus-nocem-directory) "cache"))
(defun gnus-nocem-scan-groups ()
"Scan all NoCeM groups for new NoCeM messages."
(interactive)
(let ((groups gnus-nocem-groups)
group active gactive articles)
(or (file-exists-p gnus-nocem-directory)
(make-directory gnus-nocem-directory t))
;; Load any previous NoCeM headers.
(gnus-nocem-load-cache)
;; Read the active file if it hasn't been read yet.
(and (file-exists-p (gnus-nocem-active-file))
(not gnus-nocem-active)
(condition-case ()
(load (gnus-nocem-active-file) t t t)
(error nil)))
;; Go through all groups and see whether new articles have
;; arrived.
(while (setq group (pop groups))
(if (not (setq gactive (gnus-activate-group group)))
() ; This group doesn't exist.
(setq active (nth 1 (assoc group gnus-nocem-active)))
(when (and (not (< (cdr gactive) (car gactive))) ; Empty group.
(or (not active)
(< (cdr active) (cdr gactive))))
;; Ok, there are new articles in this group, se we fetch the
;; headers.
(save-excursion
(let ((dependencies (make-vector 10 nil))
(buffer (nnheader-set-temp-buffer " *Gnus NoCeM*"))
headers)
(setq headers
(if (eq 'nov
(gnus-retrieve-headers
(setq articles
(gnus-uncompress-range
(cons
(if active (1+ (cdr active))
(car gactive))
(cdr gactive))))
group))
(gnus-get-newsgroup-headers-xover
articles nil dependencies)
(gnus-get-newsgroup-headers dependencies)))
(while headers
;; We take a closer look on all articles that have
;; "@@NCM" in the subject.
(when (string-match "@@NCM"
(mail-header-subject (car headers)))
(gnus-nocem-check-article group (car headers)))
(setq headers (cdr headers)))
(kill-buffer (current-buffer)))))
(setq gnus-nocem-active
(cons (list group gactive)
(delq (assoc group gnus-nocem-active)
gnus-nocem-active)))))
;; Save the results, if any.
(gnus-nocem-save-cache)
(gnus-nocem-save-active)))
(defun gnus-nocem-check-article (group header)
"Check whether the current article is an NCM article and that we want it."
;; Get the article.
(gnus-message 7 "Checking article %d in %s for NoCeM..."
(mail-header-number header) group)
(let ((date (mail-header-date header))
issuer b e)
(when (or (not date)
(nnmail-time-less
(nnmail-time-since (nnmail-date-to-time date))
(nnmail-days-to-time gnus-nocem-expiry-wait)))
(gnus-request-article-this-buffer (mail-header-number header) group)
(goto-char (point-min))
;; The article has to have proper NoCeM headers.
(when (and (setq b (search-forward "\n@@BEGIN NCM HEADERS\n" nil t))
(setq e (search-forward "\n@@BEGIN NCM BODY\n" nil t)))
;; We get the name of the issuer.
(narrow-to-region b e)
(setq issuer (mail-fetch-field "issuer"))
(and (member issuer gnus-nocem-issuers) ; We like her...
(gnus-nocem-verify-issuer issuer) ; She is who she says she is..
(gnus-nocem-enter-article)))))) ; We gobble the message.
(defun gnus-nocem-verify-issuer (person)
"Verify using PGP that the canceler is who she says she is."
(widen)
(if (fboundp gnus-nocem-verifyer)
(funcall gnus-nocem-verifyer)
;; If we don't have MailCrypt, then we use the message anyway.
t))
(defun gnus-nocem-enter-article ()
"Enter the current article into the NoCeM cache."
(goto-char (point-min))
(let ((b (search-forward "\n@@BEGIN NCM BODY\n" nil t))
(e (search-forward "\n@@END NCM BODY\n" nil t))
(buf (current-buffer))
ncm id)
(when (and b e)
(narrow-to-region b (1+ (match-beginning 0)))
(goto-char (point-min))
(while (search-forward "\t" nil t)
(when (condition-case nil
(boundp (let ((obarray gnus-active-hashtb)) (read buf)))
(error nil))
(beginning-of-line)
(while (= (following-char) ?\t)
(forward-line -1))
(setq id (buffer-substring (point) (1- (search-forward "\t"))))
(push id ncm)
(gnus-sethash id t gnus-nocem-hashtb)
(forward-line 1)
(while (= (following-char) ?\t)
(forward-line 1))))
(when ncm
(setq gnus-nocem-touched-alist t)
(push (cons (let ((time (current-time))) (setcdr (cdr time) nil) time)
ncm)
gnus-nocem-alist)))))
(defun gnus-nocem-load-cache ()
"Load the NoCeM cache."
(unless gnus-nocem-alist
;; The buffer doesn't exist, so we create it and load the NoCeM
;; cache.
(when (file-exists-p (gnus-nocem-cache-file))
(load (gnus-nocem-cache-file) t t t)
(gnus-nocem-alist-to-hashtb))))
(defun gnus-nocem-save-cache ()
"Save the NoCeM cache."
(when (and gnus-nocem-alist
gnus-nocem-touched-alist)
(nnheader-temp-write (gnus-nocem-cache-file)
(prin1 `(setq gnus-nocem-alist ',gnus-nocem-alist) (current-buffer)))
(setq gnus-nocem-touched-alist nil)))
(defun gnus-nocem-save-active ()
"Save the NoCeM active file."
(nnheader-temp-write (gnus-nocem-active-file)
(prin1 `(setq gnus-nocem-active ',gnus-nocem-active) (current-buffer))))
(defun gnus-nocem-alist-to-hashtb ()
"Create a hashtable from the Message-IDs we have."
(let* ((alist gnus-nocem-alist)
(pprev (cons nil alist))
(prev pprev)
(expiry (nnmail-days-to-time gnus-nocem-expiry-wait))
entry)
(setq gnus-nocem-hashtb (gnus-make-hashtable (* (length alist) 51)))
(while (setq entry (car alist))
(if (not (nnmail-time-less (nnmail-time-since (car entry)) expiry))
;; This entry has expired, so we remove it.
(setcdr prev (cdr alist))
(setq prev alist)
;; This is ok, so we enter it into the hashtable.
(setq entry (cdr entry))
(while entry
(gnus-sethash (car entry) t gnus-nocem-hashtb)
(setq entry (cdr entry))))
(setq alist (cdr alist)))))
(gnus-add-shutdown 'gnus-nocem-close 'gnus)
(defun gnus-nocem-close ()
"Clear internal NoCeM variables."
(setq gnus-nocem-alist nil
gnus-nocem-hashtb nil
gnus-nocem-active nil
gnus-nocem-touched-alist nil))
(defun gnus-nocem-unwanted-article-p (id)
"Say whether article ID in the current group is wanted."
(gnus-gethash id gnus-nocem-hashtb))
(provide 'gnus-nocem)
;;; gnus-nocem.el ends here