1 ;;; gnus-async.el --- asynchronous support for Gnus
2 ;; Copyright (C) 1996 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.
32 (defvar gnus-asynchronous t
33 "*If nil, inhibit all Gnus asynchronicity.
34 If non-nil, let the other asynch variables be heeded.")
36 (defvar gnus-use-article-prefetch 30
37 "*If non-nil, prefetch articles in groups that allow this.
38 If a number, prefetch only that many articles forward;
39 if t, prefetch as many articles as possible.")
41 (defvar gnus-prefetched-article-deletion-strategy '(read exit)
42 "List of symbols that say when to remove articles from the prefetch buffer.
43 Possible values in this list are `read', which means that
44 articles are removed as they are read, and `exit', which means
45 that all articles belonging to a group are removed on exit
48 (defvar gnus-use-header-prefetch nil
49 "*If non-nil, prefetch the headers to the next group.")
51 ;;; Internal variables.
53 (defvar gnus-async-prefetch-article-buffer " *Async Prefetch Article*")
54 (defvar gnus-async-article-alist nil)
55 (defvar gnus-async-article-semaphore '(nil))
56 (defvar gnus-async-fetch-list nil)
58 (defvar gnus-async-prefetch-headers-buffer " *Async Prefetch Headers*")
59 (defvar gnus-async-header-prefetched nil)
61 ;;; Utility functions.
63 (defun gnus-group-asynchronous-p (group)
64 "Say whether GROUP is fetched from a server that supports asynchronocity."
65 (gnus-asynchronous-p (gnus-find-method-for-group group)))
67 ;;; Somewhat bogus semaphores.
69 (defun gnus-async-get-semaphore (semaphore)
70 "Wait until SEMAPHORE is released."
71 (while (/= (length (nconc (symbol-value semaphore) (list nil))) 2)
74 (defun gnus-async-release-semaphore (semaphore)
76 (setcdr (symbol-value semaphore) nil))
82 (gnus-add-shutdown 'gnus-async-close 'gnus)
83 (defun gnus-async-close ()
84 (gnus-kill-buffer gnus-async-prefetch-article-buffer)
85 (gnus-kill-buffer gnus-async-prefetch-headers-buffer)
86 (setq gnus-async-article-alist nil
87 gnus-async-header-prefetched nil))
89 (defun gnus-async-set-buffer ()
90 (nnheader-set-temp-buffer gnus-async-prefetch-article-buffer t))
92 (defun gnus-async-prefetch-next (group article summary)
93 "Possibly prefetch several articles starting with the article after ARTICLE."
94 (when (gnus-buffer-live-p summary)
96 (set-buffer gnus-summary-buffer)
97 (let ((next (caadr (gnus-data-find-list article))))
100 (gnus-async-prefetch-article group next summary)
102 0.1 nil 'gnus-async-prefetch-article group next summary)))))))
104 (defun gnus-async-prefetch-article (group article summary &optional next)
105 "Possibly prefetch several articles starting with ARTICLE."
106 (when (and gnus-asynchronous
109 (gnus-async-get-semaphore 'gnus-async-article-semaphore)
110 (pop gnus-async-fetch-list)
111 (gnus-async-release-semaphore 'gnus-async-article-semaphore))
112 (let ((do-fetch next))
113 (when (and (gnus-group-asynchronous-p group)
114 (gnus-buffer-live-p summary)
116 gnus-async-fetch-list))
119 (gnus-async-get-semaphore 'gnus-async-article-semaphore)
121 (setq do-fetch (not gnus-async-fetch-list))
122 ;; Nix out any outstanding requests.
123 (setq gnus-async-fetch-list nil)
124 ;; Fill in the new list.
125 (let ((n gnus-use-article-prefetch)
126 (data (gnus-data-find-list article))
128 (while (and (setq d (pop data))
132 (unless (or (gnus-async-prefetched-article-entry
133 group (setq article (gnus-data-number d)))
134 (not (natnump article)))
135 ;; Not already fetched -- so we add it to the list.
136 (push article gnus-async-fetch-list)))
137 (setq gnus-async-fetch-list
138 (nreverse gnus-async-fetch-list))))
141 (setq article (car gnus-async-fetch-list))))
143 (gnus-async-release-semaphore 'gnus-async-article-semaphore))
145 (when (and do-fetch article)
146 ;; We want to fetch some more articles.
150 (gnus-async-set-buffer)
151 (goto-char (point-max))
152 (setq mark (point-marker))
153 (let ((nnheader-callback-function
154 (gnus-make-async-article-function
155 group article mark summary next))
156 (nntp-server-buffer (get-buffer
157 gnus-async-prefetch-article-buffer)))
158 (gnus-message 7 "Prefetching article %d in group %s"
160 (gnus-request-article article group)))))))))
162 (defun gnus-make-async-article-function (group article mark summary next)
163 "Return a callback function."
166 (gnus-async-set-buffer)
167 (gnus-async-get-semaphore 'gnus-async-article-semaphore)
168 (push (list ',(intern (format "%s-%d" group article))
169 ,mark (set-marker (make-marker)
172 gnus-async-article-alist)
173 (gnus-async-release-semaphore
174 'gnus-async-article-semaphore)
175 (when (gnus-buffer-live-p ,summary)
176 (gnus-async-prefetch-article
177 ,group ,next ,summary t)))))
179 (defun gnus-async-request-fetched-article (group article buffer)
180 "See whether we have ARTICLE from GROUP and put it in BUFFER."
181 (when (numberp article)
182 (let ((entry (gnus-async-prefetched-article-entry group article)))
185 (gnus-async-set-buffer)
186 (copy-to-buffer buffer (cadr entry) (caddr entry))
187 ;; Remove the read article from the prefetch buffer.
188 (when (memq 'read gnus-prefetched-article-deletion-strategy)
189 (gnus-async-delete-prefected-entry entry))
192 (defun gnus-async-delete-prefected-entry (entry)
193 "Delete ENTRY from buffer and alist."
194 (delete-region (cadr entry) (caddr entry))
195 (set-marker (cadr entry) nil)
196 (set-marker (caddr entry) nil)
197 (gnus-async-get-semaphore 'gnus-async-article-semaphore)
198 (setq gnus-async-article-alist
199 (delq entry gnus-async-article-alist))
200 (gnus-async-release-semaphore 'gnus-async-article-semaphore))
202 (defun gnus-async-prefetch-remove-group (group)
203 "Remove all articles belonging to GROUP from the prefetch buffer."
204 (when (and (gnus-group-asynchronous-p group)
205 (memq 'exit gnus-prefetched-article-deletion-strategy))
206 (let ((alist gnus-async-article-alist))
208 (gnus-async-set-buffer)
210 (when (equal group (nth 3 (car alist)))
211 (gnus-async-delete-prefected-entry (car alist)))
214 (defun gnus-async-prefetched-article-entry (group article)
215 "Return the entry for ARTICLE in GROUP iff it has been prefetched."
216 (assq (intern (format "%s-%d" group article))
217 gnus-async-article-alist))
223 (defun gnus-async-prefetch-headers (group)
224 "Prefetch the headers for group GROUP."
227 (when (and gnus-use-header-prefetch
229 (gnus-group-asynchronous-p group)
230 (listp gnus-async-header-prefetched)
231 (setq unread (gnus-list-of-unread-articles group)))
232 ;; Mark that a fetch is in progress.
233 (setq gnus-async-header-prefetched t)
234 (nnheader-set-temp-buffer gnus-async-prefetch-headers-buffer t)
236 (let ((nntp-server-buffer (current-buffer))
237 (nnheader-callback-function
239 (setq gnus-async-header-prefetched
240 ,(cons group unread)))))
241 (gnus-retrieve-headers unread group gnus-fetch-old-headers))))))
243 (defun gnus-async-retrieve-fetched-headers (articles group)
244 "See whether we have prefetched headers."
245 (when (and gnus-use-header-prefetch
246 (gnus-group-asynchronous-p group)
247 (listp gnus-async-header-prefetched)
248 (equal group (car gnus-async-header-prefetched))
249 (equal articles (cdr gnus-async-header-prefetched)))
251 (nnheader-set-temp-buffer gnus-async-prefetch-headers-buffer t)
253 (copy-to-buffer nntp-server-buffer (point-min) (point-max))
255 (setq gnus-async-header-prefetched nil)
258 (provide 'gnus-async)
260 ;;; gnus-async.el ends here