1 ;;; gnus-async.el --- asynchronous support for Gnus
3 ;; Copyright (C) 1996-2011 Free Software Foundation, Inc.
5 ;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
8 ;; This file is part of GNU Emacs.
10 ;; GNU Emacs is free software: you can redistribute it and/or modify
11 ;; it under the terms of the GNU General Public License as published by
12 ;; the Free Software Foundation, either version 3 of the License, or
13 ;; (at your option) any later version.
15 ;; GNU Emacs is distributed in the hope that it will be useful,
16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 ;; GNU General Public License for more details.
20 ;; You should have received a copy of the GNU General Public License
21 ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
27 (eval-when-compile (require 'cl
))
33 (defgroup gnus-asynchronous nil
34 "Support for asynchronous operations."
37 (defcustom gnus-use-article-prefetch
30
38 "*If non-nil, prefetch articles in groups that allow this.
39 If a number, prefetch only that many articles forward;
40 if t, prefetch as many articles as possible."
41 :group
'gnus-asynchronous
42 :type
'(choice (const :tag
"off" nil
)
44 (integer :tag
"some" 0)))
46 (defcustom gnus-asynchronous nil
47 "*If nil, inhibit all Gnus asynchronicity.
48 If non-nil, let the other asynch variables be heeded."
49 :group
'gnus-asynchronous
52 (defcustom gnus-prefetched-article-deletion-strategy
'(read exit
)
53 "List of symbols that say when to remove articles from the prefetch buffer.
54 Possible values in this list are `read', which means that
55 articles are removed as they are read, and `exit', which means
56 that all articles belonging to a group are removed on exit
58 :group
'gnus-asynchronous
59 :type
'(set (const read
) (const exit
)))
61 (defcustom gnus-use-header-prefetch nil
62 "*If non-nil, prefetch the headers to the next group."
63 :group
'gnus-asynchronous
66 (defcustom gnus-async-prefetch-article-p
'gnus-async-unread-p
67 "Function called to say whether an article should be prefetched or not.
68 The function is called with one parameter -- the article data.
69 It should return non-nil if the article is to be prefetched."
70 :group
'gnus-asynchronous
73 (defcustom gnus-async-post-fetch-function nil
74 "Function called after an article has been prefetched.
75 The function will be called narrowed to the region of the article
77 :group
'gnus-asynchronous
80 ;;; Internal variables.
82 (defvar gnus-async-prefetch-article-buffer
" *Async Prefetch Article*")
83 (defvar gnus-async-article-alist nil
)
84 (defvar gnus-async-article-semaphore
'(nil))
85 (defvar gnus-async-fetch-list nil
)
86 (defvar gnus-async-hashtb nil
)
87 (defvar gnus-async-current-prefetch-group nil
)
88 (defvar gnus-async-current-prefetch-article nil
)
89 (defvar gnus-async-timer nil
)
91 (defvar gnus-async-prefetch-headers-buffer
" *Async Prefetch Headers*")
92 (defvar gnus-async-header-prefetched nil
)
94 ;;; Utility functions.
96 (defun gnus-group-asynchronous-p (group)
97 "Say whether GROUP is fetched from a server that supports asynchronicity."
98 (gnus-asynchronous-p (gnus-find-method-for-group group
)))
100 ;;; Somewhat bogus semaphores.
102 (defun gnus-async-get-semaphore (semaphore)
103 "Wait until SEMAPHORE is released."
104 (while (/= (length (nconc (symbol-value semaphore
) (list nil
))) 2)
107 (defun gnus-async-release-semaphore (semaphore)
109 (setcdr (symbol-value semaphore
) nil
))
111 (defmacro gnus-async-with-semaphore
(&rest forms
)
114 (gnus-async-get-semaphore 'gnus-async-article-semaphore
)
116 (gnus-async-release-semaphore 'gnus-async-article-semaphore
)))
118 (put 'gnus-async-with-semaphore
'lisp-indent-function
0)
119 (put 'gnus-async-with-semaphore
'edebug-form-spec
'(body))
125 (gnus-add-shutdown 'gnus-async-close
'gnus
)
126 (defun gnus-async-close ()
127 (gnus-kill-buffer gnus-async-prefetch-article-buffer
)
128 (gnus-kill-buffer gnus-async-prefetch-headers-buffer
)
129 (setq gnus-async-hashtb nil
130 gnus-async-article-alist nil
131 gnus-async-header-prefetched nil
))
133 (defun gnus-async-set-buffer ()
134 (nnheader-set-temp-buffer gnus-async-prefetch-article-buffer t
)
135 (unless gnus-async-hashtb
136 (setq gnus-async-hashtb
(gnus-make-hashtable 1023))))
138 (defun gnus-async-halt-prefetch ()
140 (setq gnus-async-fetch-list nil
))
142 (defun gnus-async-prefetch-next (group article summary
)
143 "Possibly prefetch several articles starting with the article after ARTICLE."
144 (when (and (gnus-buffer-live-p summary
)
146 (gnus-group-asynchronous-p group
))
147 (with-current-buffer gnus-summary-buffer
148 (let ((next (caadr (gnus-data-find-list article
))))
150 (if (not (fboundp 'run-with-idle-timer
))
151 ;; This is either an older Emacs or XEmacs, so we
152 ;; do this, which leads to slightly slower article
154 (gnus-async-prefetch-article group next summary
)
155 (when gnus-async-timer
157 (nnheader-cancel-timer 'gnus-async-timer
)))
158 (setq gnus-async-timer
160 0.1 nil
'gnus-async-prefetch-article
161 group next summary
))))))))
163 (defun gnus-async-prefetch-article (group article summary
&optional next
)
164 "Possibly prefetch several articles starting with ARTICLE."
165 (if (not (gnus-buffer-live-p summary
))
166 (gnus-async-with-semaphore
167 (setq gnus-async-fetch-list nil
))
168 (when (and gnus-asynchronous
171 (gnus-async-with-semaphore
172 (pop gnus-async-fetch-list
)))
173 (let ((do-fetch next
)
174 (do-message t
)) ;(eq major-mode 'gnus-summary-mode)))
175 (when (and (gnus-group-asynchronous-p group
)
176 (gnus-buffer-live-p summary
)
178 gnus-async-fetch-list
))
179 (gnus-async-with-semaphore
181 (setq do-fetch
(not gnus-async-fetch-list
))
182 ;; Nix out any outstanding requests.
183 (setq gnus-async-fetch-list nil
)
184 ;; Fill in the new list.
185 (let ((n gnus-use-article-prefetch
)
186 (data (gnus-data-find-list article
))
188 (while (and (setq d
(pop data
))
192 (unless (or (gnus-async-prefetched-article-entry
193 group
(setq article
(gnus-data-number d
)))
194 (not (natnump article
))
195 (not (funcall gnus-async-prefetch-article-p d
)))
196 ;; Not already fetched -- so we add it to the list.
197 (push article gnus-async-fetch-list
)))
198 (setq gnus-async-fetch-list
199 (nreverse gnus-async-fetch-list
))))
202 (setq article
(car gnus-async-fetch-list
))))
204 (when (and do-fetch article
)
205 ;; We want to fetch some more articles.
206 (with-current-buffer summary
208 (gnus-async-set-buffer)
209 (goto-char (point-max))
210 (setq mark
(point-marker))
211 (let ((nnheader-callback-function
212 (gnus-make-async-article-function
213 group article mark summary next
))
215 (get-buffer gnus-async-prefetch-article-buffer
)))
217 (gnus-message 9 "Prefetching article %d in group %s"
219 (setq gnus-async-current-prefetch-group group
)
220 (setq gnus-async-current-prefetch-article article
)
221 (gnus-request-article article group
))))))))))
223 (defun gnus-make-async-article-function (group article mark summary next
)
224 "Return a callback function."
226 (gnus-async-article-callback arg
,group
,article
,mark
,summary
,next
)))
229 (autoload 'gnus-html-prefetch-images
"gnus-html"))
231 (defun gnus-async-article-callback (arg group article mark summary next
)
232 "Function called when an async article is done being fetched."
234 (setq gnus-async-current-prefetch-article nil
)
236 (gnus-async-set-buffer)
239 (narrow-to-region mark
(point-max))
240 ;; Prefetch images for the groups that want that.
241 (when (fboundp 'gnus-html-prefetch-images
)
242 (gnus-html-prefetch-images summary
))
243 (when gnus-async-post-fetch-function
244 (funcall gnus-async-post-fetch-function summary
))))
245 (gnus-async-with-semaphore
247 gnus-async-article-alist
248 (cons (list (intern (format "%s-%d" group article
)
250 mark
(set-marker (make-marker) (point-max))
252 gnus-async-article-alist
))))
253 (if (not (gnus-buffer-live-p summary
))
254 (gnus-async-with-semaphore
255 (setq gnus-async-fetch-list nil
))
256 (gnus-async-prefetch-article group next summary t
))))
258 (defun gnus-async-unread-p (data)
259 "Return non-nil if DATA represents an unread article."
260 (gnus-data-unread-p data
))
262 (defun gnus-async-request-fetched-article (group article buffer
)
263 "See whether we have ARTICLE from GROUP and put it in BUFFER."
264 (when (numberp article
)
265 (when (and (equal group gnus-async-current-prefetch-group
)
266 (eq article gnus-async-current-prefetch-article
))
267 (gnus-async-wait-for-article article
))
268 (let ((entry (gnus-async-prefetched-article-entry group article
)))
271 (gnus-async-set-buffer)
272 (copy-to-buffer buffer
(cadr entry
) (caddr entry
))
273 ;; Remove the read article from the prefetch buffer.
274 (when (memq 'read gnus-prefetched-article-deletion-strategy
)
275 (gnus-async-delete-prefetched-entry entry
))
278 (defun gnus-async-wait-for-article (article)
279 "Wait until ARTICLE is no longer the currently-being-fetched article."
281 (gnus-async-set-buffer)
282 (let ((proc (nntp-find-connection (current-buffer)))
283 (nntp-server-buffer (current-buffer))
284 (nntp-have-messaged nil
)
288 ;; FIXME: we could stop waiting after some
289 ;; timeout, but this is the wrong place to do it.
290 ;; rather than checking time-spent-waiting, we
291 ;; should check time-since-last-output, which
292 ;; needs to be done in nntp.el.
293 (while (eq article gnus-async-current-prefetch-article
)
295 (when (nntp-accept-process-output proc
)
297 (when (and (not nntp-have-messaged
)
299 (gnus-message 5 "Waiting for async article...")
300 (setq nntp-have-messaged t
)))
302 ;; if the user interrupted on a slow/hung connection,
303 ;; do something friendly.
305 (setq gnus-async-current-prefetch-article nil
))
307 (when nntp-have-messaged
308 (gnus-message 5 ""))))))
310 (defun gnus-async-delete-prefetched-entry (entry)
311 "Delete ENTRY from buffer and alist."
313 (delete-region (cadr entry
) (caddr entry
))
314 (set-marker (cadr entry
) nil
)
315 (set-marker (caddr entry
) nil
))
316 (gnus-async-with-semaphore
317 (setq gnus-async-article-alist
318 (delq entry gnus-async-article-alist
))
319 (unintern (car entry
) gnus-async-hashtb
)))
321 (defun gnus-async-prefetch-remove-group (group)
322 "Remove all articles belonging to GROUP from the prefetch buffer."
323 (when (and (gnus-group-asynchronous-p group
)
324 (memq 'exit gnus-prefetched-article-deletion-strategy
))
326 (gnus-async-set-buffer)
327 (dolist (entry gnus-async-article-alist
)
328 (when (equal group
(nth 3 entry
))
329 (gnus-async-delete-prefetched-entry entry
))))))
331 (defun gnus-async-prefetched-article-entry (group article
)
332 "Return the entry for ARTICLE in GROUP if it has been prefetched."
333 (let ((entry (save-excursion
334 (gnus-async-set-buffer)
335 (assq (intern-soft (format "%s-%d" group article
)
337 gnus-async-article-alist
))))
338 ;; Perhaps something has emptied the buffer?
340 (= (cadr entry
) (caddr entry
)))
343 (set-marker (cadr entry
) nil
)
344 (set-marker (caddr entry
) nil
))
345 (setq gnus-async-article-alist
346 (delq entry gnus-async-article-alist
))
354 (defun gnus-async-prefetch-headers (group)
355 "Prefetch the headers for group GROUP."
358 (when (and gnus-use-header-prefetch
360 (gnus-group-asynchronous-p group
)
361 (listp gnus-async-header-prefetched
)
362 (setq unread
(gnus-list-of-unread-articles group
)))
363 ;; Mark that a fetch is in progress.
364 (setq gnus-async-header-prefetched t
)
365 (nnheader-set-temp-buffer gnus-async-prefetch-headers-buffer t
)
367 (let ((nntp-server-buffer (current-buffer))
368 (nnheader-callback-function
370 (setq gnus-async-header-prefetched
371 ,(cons group unread
)))))
372 (gnus-retrieve-headers unread group gnus-fetch-old-headers
))))))
374 (defun gnus-async-retrieve-fetched-headers (articles group
)
375 "See whether we have prefetched headers."
376 (when (and gnus-use-header-prefetch
377 (gnus-group-asynchronous-p group
)
378 (listp gnus-async-header-prefetched
)
379 (equal group
(car gnus-async-header-prefetched
))
380 (equal articles
(cdr gnus-async-header-prefetched
)))
382 (nnheader-set-temp-buffer gnus-async-prefetch-headers-buffer t
)
384 (copy-to-buffer nntp-server-buffer
(point-min) (point-max))
386 (setq gnus-async-header-prefetched nil
)
389 (provide 'gnus-async
)
391 ;;; gnus-async.el ends here