1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
|
;;; gnus-async.el --- asynchronous support for Gnus
;; Copyright (C) 1996-2017 Free Software Foundation, Inc.
;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
;; 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 3 of the License, 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. If not, see <http://www.gnu.org/licenses/>.
;;; Commentary:
;;; Code:
(eval-when-compile (require 'cl))
(require 'gnus)
(require 'gnus-sum)
(require 'nntp)
(defgroup gnus-asynchronous nil
"Support for asynchronous operations."
:group 'gnus)
(defcustom gnus-use-article-prefetch 30
"*If non-nil, prefetch articles in groups that allow this.
If a number, prefetch only that many articles forward;
if t, prefetch as many articles as possible."
:group 'gnus-asynchronous
:type '(choice (const :tag "off" nil)
(const :tag "all" t)
(integer :tag "some" 0)))
(defcustom gnus-asynchronous nil
"*If nil, inhibit all Gnus asynchronicity.
If non-nil, let the other asynch variables be heeded."
:group 'gnus-asynchronous
:type 'boolean)
(defcustom gnus-prefetched-article-deletion-strategy '(read exit)
"List of symbols that say when to remove articles from the prefetch buffer.
Possible values in this list are `read', which means that
articles are removed as they are read, and `exit', which means
that all articles belonging to a group are removed on exit
from that group."
:group 'gnus-asynchronous
:type '(set (const read) (const exit)))
(defcustom gnus-use-header-prefetch nil
"*If non-nil, prefetch the headers to the next group."
:group 'gnus-asynchronous
:type 'boolean)
(defcustom gnus-async-prefetch-article-p 'gnus-async-unread-p
"Function called to say whether an article should be prefetched or not.
The function is called with one parameter -- the article data.
It should return non-nil if the article is to be prefetched."
:group 'gnus-asynchronous
:type 'function)
(defcustom gnus-async-post-fetch-function nil
"Function called after an article has been prefetched.
The function will be called narrowed to the region of the article
that was fetched."
:version "24.1"
:group 'gnus-asynchronous
:type '(choice (const nil) function))
;;; Internal variables.
(defvar gnus-async-prefetch-article-buffer " *Async Prefetch Article*")
(defvar gnus-async-article-alist nil)
(defvar gnus-async-article-semaphore '(nil))
(defvar gnus-async-fetch-list nil)
(defvar gnus-async-hashtb nil)
(defvar gnus-async-current-prefetch-group nil)
(defvar gnus-async-current-prefetch-article nil)
(defvar gnus-async-timer nil)
(defvar gnus-async-prefetch-headers-buffer " *Async Prefetch Headers*")
(defvar gnus-async-header-prefetched nil)
;;; Utility functions.
(defun gnus-group-asynchronous-p (group)
"Say whether GROUP is fetched from a server that supports asynchronicity."
(gnus-asynchronous-p (gnus-find-method-for-group group)))
;;; Somewhat bogus semaphores.
(defun gnus-async-get-semaphore (semaphore)
"Wait until SEMAPHORE is released."
(while (/= (length (nconc (symbol-value semaphore) (list nil))) 2)
(sleep-for 1)))
(defun gnus-async-release-semaphore (semaphore)
"Release SEMAPHORE."
(setcdr (symbol-value semaphore) nil))
(defmacro gnus-async-with-semaphore (&rest forms)
`(unwind-protect
(progn
(gnus-async-get-semaphore 'gnus-async-article-semaphore)
,@forms)
(gnus-async-release-semaphore 'gnus-async-article-semaphore)))
(put 'gnus-async-with-semaphore 'lisp-indent-function 0)
(put 'gnus-async-with-semaphore 'edebug-form-spec '(body))
;;;
;;; Article prefetch
;;;
(gnus-add-shutdown 'gnus-async-close 'gnus)
(defun gnus-async-close ()
(gnus-kill-buffer gnus-async-prefetch-article-buffer)
(gnus-kill-buffer gnus-async-prefetch-headers-buffer)
(setq gnus-async-hashtb nil
gnus-async-article-alist nil
gnus-async-header-prefetched nil))
(defun gnus-async-set-buffer ()
(nnheader-set-temp-buffer gnus-async-prefetch-article-buffer t)
(unless gnus-async-hashtb
(setq gnus-async-hashtb (gnus-make-hashtable 1023))))
(defun gnus-async-halt-prefetch ()
"Stop prefetching."
(setq gnus-async-fetch-list nil))
(defun gnus-async-prefetch-next (group article summary)
"Possibly prefetch several articles starting with the article after ARTICLE."
(when (and (gnus-buffer-live-p summary)
gnus-asynchronous
(gnus-group-asynchronous-p group))
(with-current-buffer gnus-summary-buffer
(let ((next (caadr (gnus-data-find-list article))))
(when next
(if (not (fboundp 'run-with-idle-timer))
;; This is either an older Emacs or XEmacs, so we
;; do this, which leads to slightly slower article
;; buffer display.
(gnus-async-prefetch-article group next summary)
(when gnus-async-timer
(ignore-errors
(nnheader-cancel-timer 'gnus-async-timer)))
(setq gnus-async-timer
(run-with-idle-timer
0.1 nil 'gnus-async-prefetch-article
group next summary))))))))
(defun gnus-async-prefetch-article (group article summary &optional next)
"Possibly prefetch several articles starting with ARTICLE."
(if (not (gnus-buffer-live-p summary))
(gnus-async-with-semaphore
(setq gnus-async-fetch-list nil))
(when (and gnus-asynchronous
(gnus-alive-p))
(when next
(gnus-async-with-semaphore
(pop gnus-async-fetch-list)))
(let ((do-fetch next)
(do-message t)) ;(eq major-mode 'gnus-summary-mode)))
(when (and (gnus-group-asynchronous-p group)
(gnus-buffer-live-p summary)
(or (not next)
gnus-async-fetch-list))
(gnus-async-with-semaphore
(unless next
(setq do-fetch (not gnus-async-fetch-list))
;; Nix out any outstanding requests.
(setq gnus-async-fetch-list nil)
;; Fill in the new list.
(let ((n gnus-use-article-prefetch)
(data (gnus-data-find-list article))
d)
(while (and (setq d (pop data))
(if (numberp n)
(natnump (decf n))
n))
(unless (or (gnus-async-prefetched-article-entry
group (setq article (gnus-data-number d)))
(not (natnump article))
(not (funcall gnus-async-prefetch-article-p d)))
;; Not already fetched -- so we add it to the list.
(push article gnus-async-fetch-list)))
(setq gnus-async-fetch-list
(nreverse gnus-async-fetch-list))))
(when do-fetch
(setq article (car gnus-async-fetch-list))))
(when (and do-fetch article)
;; We want to fetch some more articles.
(with-current-buffer summary
(let (mark)
(gnus-async-set-buffer)
(goto-char (point-max))
(setq mark (point-marker))
(let ((nnheader-callback-function
(gnus-make-async-article-function
group article mark summary next))
(nntp-server-buffer
(get-buffer gnus-async-prefetch-article-buffer)))
(when do-message
(gnus-message 9 "Prefetching article %d in group %s"
article group))
(setq gnus-async-current-prefetch-group group)
(setq gnus-async-current-prefetch-article article)
(gnus-request-article article group))))))))))
(defun gnus-make-async-article-function (group article mark summary next)
"Return a callback function."
`(lambda (arg)
(gnus-async-article-callback arg ,group ,article ,mark ,summary ,next)))
(defun gnus-async-article-callback (arg group article mark summary next)
"Function called when an async article is done being fetched."
(save-excursion
(setq gnus-async-current-prefetch-article nil)
(when arg
(gnus-async-set-buffer)
(save-excursion
(save-restriction
(narrow-to-region mark (point-max))
;; Put the articles into the agent, if they aren't already.
(when (and gnus-agent
(gnus-agent-group-covered-p group))
(save-restriction
(narrow-to-region mark (point-max))
(gnus-agent-store-article article group)))
;; Prefetch images for the groups that want that.
(when (fboundp 'gnus-html-prefetch-images)
(gnus-html-prefetch-images summary))
(when gnus-async-post-fetch-function
(funcall gnus-async-post-fetch-function summary))))
(gnus-async-with-semaphore
(setq
gnus-async-article-alist
(cons (list (intern (format "%s-%d" group article)
gnus-async-hashtb)
mark (point-max-marker)
group article)
gnus-async-article-alist))))
(if (not (gnus-buffer-live-p summary))
(gnus-async-with-semaphore
(setq gnus-async-fetch-list nil))
(gnus-async-prefetch-article group next summary t))))
(defun gnus-async-unread-p (data)
"Return non-nil if DATA represents an unread article."
(gnus-data-unread-p data))
(defun gnus-async-request-fetched-article (group article buffer)
"See whether we have ARTICLE from GROUP and put it in BUFFER."
(when (numberp article)
(when (and (equal group gnus-async-current-prefetch-group)
(eq article gnus-async-current-prefetch-article))
(gnus-async-wait-for-article article))
(let ((entry (gnus-async-prefetched-article-entry group article)))
(when entry
(save-excursion
(gnus-async-set-buffer)
(copy-to-buffer buffer (cadr entry) (caddr entry))
;; Remove the read article from the prefetch buffer.
(when (memq 'read gnus-prefetched-article-deletion-strategy)
(gnus-async-delete-prefetched-entry entry))
t)))))
(defun gnus-async-wait-for-article (article)
"Wait until ARTICLE is no longer the currently-being-fetched article."
(save-excursion
(gnus-async-set-buffer)
(let ((proc (nntp-find-connection (current-buffer)))
(nntp-server-buffer (current-buffer))
(nntp-have-messaged nil)
(tries 0))
(when proc
(condition-case nil
;; FIXME: we could stop waiting after some
;; timeout, but this is the wrong place to do it.
;; rather than checking time-spent-waiting, we
;; should check time-since-last-output, which
;; needs to be done in nntp.el.
(while (eq article gnus-async-current-prefetch-article)
(incf tries)
(when (nntp-accept-process-output proc)
(setq tries 0))
(when (and (not nntp-have-messaged)
(= tries 3))
(gnus-message 5 "Waiting for async article...")
(setq nntp-have-messaged t)))
(quit
;; if the user interrupted on a slow/hung connection,
;; do something friendly.
(when (> tries 3)
(setq gnus-async-current-prefetch-article nil))
(signal 'quit nil)))
(when nntp-have-messaged
(gnus-message 5 ""))))))
(defun gnus-async-delete-prefetched-entry (entry)
"Delete ENTRY from buffer and alist."
(ignore-errors
(delete-region (cadr entry) (caddr entry))
(set-marker (cadr entry) nil)
(set-marker (caddr entry) nil))
(gnus-async-with-semaphore
(setq gnus-async-article-alist
(delq entry gnus-async-article-alist))
(unintern (car entry) gnus-async-hashtb)))
(defun gnus-async-prefetch-remove-group (group)
"Remove all articles belonging to GROUP from the prefetch buffer."
(when (and (gnus-group-asynchronous-p group)
(memq 'exit gnus-prefetched-article-deletion-strategy))
(save-excursion
(gnus-async-set-buffer)
(dolist (entry gnus-async-article-alist)
(when (equal group (nth 3 entry))
(gnus-async-delete-prefetched-entry entry))))))
(defun gnus-async-prefetched-article-entry (group article)
"Return the entry for ARTICLE in GROUP if it has been prefetched."
(let ((entry (save-excursion
(gnus-async-set-buffer)
(assq (intern-soft (format "%s-%d" group article)
gnus-async-hashtb)
gnus-async-article-alist))))
;; Perhaps something has emptied the buffer?
(if (and entry
(= (cadr entry) (caddr entry)))
(progn
(ignore-errors
(set-marker (cadr entry) nil)
(set-marker (caddr entry) nil))
(setq gnus-async-article-alist
(delq entry gnus-async-article-alist))
nil)
entry)))
;;;
;;; Header prefetch
;;;
(defun gnus-async-prefetch-headers (group)
"Prefetch the headers for group GROUP."
(save-excursion
(let (unread)
(when (and gnus-use-header-prefetch
gnus-asynchronous
(gnus-group-asynchronous-p group)
(listp gnus-async-header-prefetched)
(setq unread (gnus-list-of-unread-articles group)))
;; Mark that a fetch is in progress.
(setq gnus-async-header-prefetched t)
(nnheader-set-temp-buffer gnus-async-prefetch-headers-buffer t)
(erase-buffer)
(let ((nntp-server-buffer (current-buffer))
(nnheader-callback-function
`(lambda (arg)
(setq gnus-async-header-prefetched
,(cons group unread)))))
(gnus-retrieve-headers unread group gnus-fetch-old-headers))))))
(defun gnus-async-retrieve-fetched-headers (articles group)
"See whether we have prefetched headers."
(when (and gnus-use-header-prefetch
(gnus-group-asynchronous-p group)
(listp gnus-async-header-prefetched)
(equal group (car gnus-async-header-prefetched))
(equal articles (cdr gnus-async-header-prefetched)))
(save-excursion
(nnheader-set-temp-buffer gnus-async-prefetch-headers-buffer t)
(nntp-decode-text)
(copy-to-buffer nntp-server-buffer (point-min) (point-max))
(erase-buffer)
(setq gnus-async-header-prefetched nil)
t)))
(provide 'gnus-async)
;;; gnus-async.el ends here
|
