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))
78 (defmacro gnus-async-with-semaphore (&rest forms)
81 (gnus-async-get-semaphore 'gnus-async-article-semaphore)
83 (gnus-async-release-semaphore 'gnus-async-article-semaphore)))
85 (put 'gnus-asynch-with-semaphore 'lisp-indent-function 0)
86 (put 'gnus-asynch-with-semaphore 'lisp-indent-hook 0)
87 (put 'gnus-asynch-with-semaphore 'edebug-form-spec '(body))
93 (gnus-add-shutdown 'gnus-async-close 'gnus)
94 (defun gnus-async-close ()
95 (gnus-kill-buffer gnus-async-prefetch-article-buffer)
96 (gnus-kill-buffer gnus-async-prefetch-headers-buffer)
97 (setq gnus-async-article-alist nil
98 gnus-async-header-prefetched nil))
100 (defun gnus-async-set-buffer ()
101 (nnheader-set-temp-buffer gnus-async-prefetch-article-buffer t))
103 (defun gnus-async-prefetch-next (group article summary)
104 "Possibly prefetch several articles starting with the article after ARTICLE."
105 (when (and (gnus-buffer-live-p summary)
107 (gnus-group-asynchronous-p group))
109 (set-buffer gnus-summary-buffer)
110 (let ((next (caadr (gnus-data-find-list article))))
112 (if (not (fboundp 'run-with-idle-timer))
113 ;; This is either an older Emacs or XEmacs, so we
114 ;; do this, which leads to slightly slower article
116 (gnus-async-prefetch-article group next summary)
118 0.1 nil 'gnus-async-prefetch-article group next summary)))))))
120 (defun gnus-async-prefetch-article (group article summary &optional next)
121 "Possibly prefetch several articles starting with ARTICLE."
122 (if (not (gnus-buffer-live-p summary))
123 (gnus-async-with-semaphore
124 (setq gnus-async-fetch-list nil))
125 (when (and gnus-asynchronous
128 (gnus-async-with-semaphore
129 (pop gnus-async-fetch-list)))
130 (let ((do-fetch next))
131 (when (and (gnus-group-asynchronous-p group)
132 (gnus-buffer-live-p summary)
134 gnus-async-fetch-list))
135 (gnus-async-with-semaphore
137 (setq do-fetch (not gnus-async-fetch-list))
138 ;; Nix out any outstanding requests.
139 (setq gnus-async-fetch-list nil)
140 ;; Fill in the new list.
141 (let ((n gnus-use-article-prefetch)
142 (data (gnus-data-find-list article))
144 (while (and (setq d (pop data))
148 (unless (or (gnus-async-prefetched-article-entry
149 group (setq article (gnus-data-number d)))
150 (not (natnump article)))
151 ;; Not already fetched -- so we add it to the list.
152 (push article gnus-async-fetch-list)))
153 (setq gnus-async-fetch-list
154 (nreverse gnus-async-fetch-list))))
157 (setq article (car gnus-async-fetch-list))))
159 (when (and do-fetch article)
160 ;; We want to fetch some more articles.
164 (gnus-async-set-buffer)
165 (goto-char (point-max))
166 (setq mark (point-marker))
167 (let ((nnheader-callback-function
168 (gnus-make-async-article-function
169 group article mark summary next))
171 (get-buffer gnus-async-prefetch-article-buffer)))
172 (gnus-message 7 "Prefetching article %d in group %s"
174 (gnus-request-article article group))))))))))
176 (defun gnus-make-async-article-function (group article mark summary next)
177 "Return a callback function."
180 (gnus-async-set-buffer)
181 (gnus-async-with-semaphore
182 (push (list ',(intern (format "%s-%d" group article))
183 ,mark (set-marker (make-marker)
186 gnus-async-article-alist))
187 (if (not (gnus-buffer-live-p ,summary))
188 (gnus-async-with-semaphore
189 (setq gnus-async-fetch-list nil))
190 (gnus-async-prefetch-article ,group ,next ,summary t)))))
192 (defun gnus-async-request-fetched-article (group article buffer)
193 "See whether we have ARTICLE from GROUP and put it in BUFFER."
194 (when (numberp article)
195 (let ((entry (gnus-async-prefetched-article-entry group article)))
198 (gnus-async-set-buffer)
199 (copy-to-buffer buffer (cadr entry) (caddr entry))
200 ;; Remove the read article from the prefetch buffer.
201 (when (memq 'read gnus-prefetched-article-deletion-strategy)
202 (gnus-async-delete-prefected-entry entry))
205 (defun gnus-async-delete-prefected-entry (entry)
206 "Delete ENTRY from buffer and alist."
207 (delete-region (cadr entry) (caddr entry))
208 (set-marker (cadr entry) nil)
209 (set-marker (caddr entry) nil)
210 (gnus-async-with-semaphore
211 (setq gnus-async-article-alist
212 (delq entry gnus-async-article-alist))))
214 (defun gnus-async-prefetch-remove-group (group)
215 "Remove all articles belonging to GROUP from the prefetch buffer."
216 (when (and (gnus-group-asynchronous-p group)
217 (memq 'exit gnus-prefetched-article-deletion-strategy))
218 (let ((alist gnus-async-article-alist))
220 (gnus-async-set-buffer)
222 (when (equal group (nth 3 (car alist)))
223 (gnus-async-delete-prefected-entry (car alist)))
226 (defun gnus-async-prefetched-article-entry (group article)
227 "Return the entry for ARTICLE in GROUP iff it has been prefetched."
228 (assq (intern (format "%s-%d" group article))
229 gnus-async-article-alist))
235 (defun gnus-async-prefetch-headers (group)
236 "Prefetch the headers for group GROUP."
239 (when (and gnus-use-header-prefetch
241 (gnus-group-asynchronous-p group)
242 (listp gnus-async-header-prefetched)
243 (setq unread (gnus-list-of-unread-articles group)))
244 ;; Mark that a fetch is in progress.
245 (setq gnus-async-header-prefetched t)
246 (nnheader-set-temp-buffer gnus-async-prefetch-headers-buffer t)
248 (let ((nntp-server-buffer (current-buffer))
249 (nnheader-callback-function
251 (setq gnus-async-header-prefetched
252 ,(cons group unread)))))
253 (gnus-retrieve-headers unread group gnus-fetch-old-headers))))))
255 (defun gnus-async-retrieve-fetched-headers (articles group)
256 "See whether we have prefetched headers."
257 (when (and gnus-use-header-prefetch
258 (gnus-group-asynchronous-p group)
259 (listp gnus-async-header-prefetched)
260 (equal group (car gnus-async-header-prefetched))
261 (equal articles (cdr gnus-async-header-prefetched)))
263 (nnheader-set-temp-buffer gnus-async-prefetch-headers-buffer t)
265 (copy-to-buffer nntp-server-buffer (point-min) (point-max))
267 (setq gnus-async-header-prefetched nil)
270 (provide 'gnus-async)
272 ;;; gnus-async.el ends here