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|
;;; gnus-async.el --- asynchronous support for Gnus
;; Copyright (C) 1996, 1997, 1998, 1999, 2000 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 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:
(eval-when-compile (require 'cl))
(require 'gnus)
(require 'gnus-sum)
(require 'nntp)
(defgroup gnus-asynchronous nil
"Support for asynchronous operations."
:group 'gnus)
(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-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-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)
;;; 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))
(save-excursion
(set-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.
(save-excursion
(set-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)
(gnus-async-with-semaphore
(setq
gnus-async-article-alist
(cons (list (intern (format "%s-%d" group article)
gnus-async-hashtb)
mark (set-marker (make-marker) (point-max))
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))
(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 1)
(setq tries 0))
(when (and (not nntp-have-messaged) (eq 3 tries))
(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 (< 3 tries)
(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))))
(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))
(let ((alist gnus-async-article-alist))
(save-excursion
(gnus-async-set-buffer)
(while alist
(when (equal group (nth 3 (car alist)))
(gnus-async-delete-prefetched-entry (car alist)))
(pop alist))))))
(defun gnus-async-prefetched-article-entry (group article)
"Return the entry for ARTICLE in GROUP iff it has been prefetched."
(let ((entry (save-excursion
(gnus-async-set-buffer)
(assq (intern (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)
;;; arch-tag: fee61de5-3ea2-4de6-8578-2f90ce89391d
;;; gnus-async.el ends here
|
