[bpt/emacs.git] / lisp / gnus / gnus-async.el

;;; gnus-async.el --- asynchronous support for Gnus

;; Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
;;   2005, 2006, 2007 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, 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., 51 Franklin Street, Fifth Floor,
;; Boston, MA 02110-1301, 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-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)

;;; 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))
      (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))))

(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 (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
Commit	Line	Data
eec82323	1	;;; gnus-async.el --- asynchronous support for Gnus
e84b4b86	2
b6c2d8c6	3	;; Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
d7a0267c	4	;; 2005, 2006, 2007 Free Software Foundation, Inc.
eec82323	5
6748645f	6	;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
eec82323 LMI	7	;; Keywords: news
	8
	9	;; This file is part of GNU Emacs.
	10
	11	;; GNU Emacs is free software; you can redistribute it and/or modify
	12	;; it under the terms of the GNU General Public License as published by
5a9dffec	13	;; the Free Software Foundation; either version 3, or (at your option)
eec82323 LMI	14	;; any later version.
	15
	16	;; GNU Emacs is distributed in the hope that it will be useful,
	17	;; but WITHOUT ANY WARRANTY; without even the implied warranty of
	18	;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	19	;; GNU General Public License for more details.
	20
	21	;; You should have received a copy of the GNU General Public License
	22	;; along with GNU Emacs; see the file COPYING. If not, write to the
3a35cf56 LK	23	;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
3a35cf56 LK	24	;; Boston, MA 02110-1301, USA.
eec82323 LMI	25
	26	;;; Commentary:
	27
	28	;;; Code:
	29
5ab7173c RS	30	(eval-when-compile (require 'cl))
5ab7173c RS	31
eec82323 LMI	32	(require 'gnus)
	33	(require 'gnus-sum)
	34	(require 'nntp)
	35
	36	(defgroup gnus-asynchronous nil
	37	"Support for asynchronous operations."
	38	:group 'gnus)
	39
eec82323 LMI	40	(defcustom gnus-use-article-prefetch 30
	41	"*If non-nil, prefetch articles in groups that allow this.
	42	If a number, prefetch only that many articles forward;
	43	if t, prefetch as many articles as possible."
	44	:group 'gnus-asynchronous
	45	:type '(choice (const :tag "off" nil)
16409b0b GM	46	(const :tag "all" t)
16409b0b GM	47	(integer :tag "some" 0)))
eec82323	48
23f87bed MB	49	(defcustom gnus-asynchronous nil
	50	"*If nil, inhibit all Gnus asynchronicity.
	51	If non-nil, let the other asynch variables be heeded."
	52	:group 'gnus-asynchronous
	53	:type 'boolean)
	54
eec82323 LMI	55	(defcustom gnus-prefetched-article-deletion-strategy '(read exit)
	56	"List of symbols that say when to remove articles from the prefetch buffer.
	57	Possible values in this list are `read', which means that
	58	articles are removed as they are read, and `exit', which means
	59	that all articles belonging to a group are removed on exit
	60	from that group."
	61	:group 'gnus-asynchronous
	62	:type '(set (const read) (const exit)))
	63
	64	(defcustom gnus-use-header-prefetch nil
	65	"*If non-nil, prefetch the headers to the next group."
	66	:group 'gnus-asynchronous
	67	:type 'boolean)
	68
	69	(defcustom gnus-async-prefetch-article-p 'gnus-async-unread-p
	70	"Function called to say whether an article should be prefetched or not.
	71	The function is called with one parameter -- the article data.
	72	It should return non-nil if the article is to be prefetched."
	73	:group 'gnus-asynchronous
	74	:type 'function)
	75
	76	;;; Internal variables.
	77
	78	(defvar gnus-async-prefetch-article-buffer " Async Prefetch Article")
	79	(defvar gnus-async-article-alist nil)
	80	(defvar gnus-async-article-semaphore '(nil))
	81	(defvar gnus-async-fetch-list nil)
16409b0b GM	82	(defvar gnus-async-hashtb nil)
	83	(defvar gnus-async-current-prefetch-group nil)
	84	(defvar gnus-async-current-prefetch-article nil)
	85	(defvar gnus-async-timer nil)
eec82323 LMI	86
	87	(defvar gnus-async-prefetch-headers-buffer " Async Prefetch Headers")
	88	(defvar gnus-async-header-prefetched nil)
	89
	90	;;; Utility functions.
	91
	92	(defun gnus-group-asynchronous-p (group)
	93	"Say whether GROUP is fetched from a server that supports asynchronicity."
	94	(gnus-asynchronous-p (gnus-find-method-for-group group)))
	95
	96	;;; Somewhat bogus semaphores.
	97
	98	(defun gnus-async-get-semaphore (semaphore)
	99	"Wait until SEMAPHORE is released."
	100	(while (/= (length (nconc (symbol-value semaphore) (list nil))) 2)
	101	(sleep-for 1)))
	102
	103	(defun gnus-async-release-semaphore (semaphore)
	104	"Release SEMAPHORE."
	105	(setcdr (symbol-value semaphore) nil))
	106
	107	(defmacro gnus-async-with-semaphore (&rest forms)
	108	`(unwind-protect
	109	(progn
	110	(gnus-async-get-semaphore 'gnus-async-article-semaphore)
	111	,@forms)
	112	(gnus-async-release-semaphore 'gnus-async-article-semaphore)))
	113
16409b0b GM	114	(put 'gnus-async-with-semaphore 'lisp-indent-function 0)
16409b0b GM	115	(put 'gnus-async-with-semaphore 'edebug-form-spec '(body))
eec82323 LMI	116
	117	;;;
	118	;;; Article prefetch
	119	;;;
	120
	121	(gnus-add-shutdown 'gnus-async-close 'gnus)
	122	(defun gnus-async-close ()
	123	(gnus-kill-buffer gnus-async-prefetch-article-buffer)
	124	(gnus-kill-buffer gnus-async-prefetch-headers-buffer)
16409b0b GM	125	(setq gnus-async-hashtb nil
16409b0b GM	126	gnus-async-article-alist nil
eec82323 LMI	127	gnus-async-header-prefetched nil))
	128
	129	(defun gnus-async-set-buffer ()
6748645f	130	(nnheader-set-temp-buffer gnus-async-prefetch-article-buffer t)
16409b0b GM	131	(unless gnus-async-hashtb
16409b0b GM	132	(setq gnus-async-hashtb (gnus-make-hashtable 1023))))
eec82323 LMI	133
	134	(defun gnus-async-halt-prefetch ()
	135	"Stop prefetching."
	136	(setq gnus-async-fetch-list nil))
	137
	138	(defun gnus-async-prefetch-next (group article summary)
	139	"Possibly prefetch several articles starting with the article after ARTICLE."
	140	(when (and (gnus-buffer-live-p summary)
	141	gnus-asynchronous
	142	(gnus-group-asynchronous-p group))
	143	(save-excursion
	144	(set-buffer gnus-summary-buffer)
	145	(let ((next (caadr (gnus-data-find-list article))))
	146	(when next
	147	(if (not (fboundp 'run-with-idle-timer))
	148	;; This is either an older Emacs or XEmacs, so we
	149	;; do this, which leads to slightly slower article
	150	;; buffer display.
	151	(gnus-async-prefetch-article group next summary)
16409b0b GM	152	(when gnus-async-timer
	153	(ignore-errors
	154	(nnheader-cancel-timer 'gnus-async-timer)))
	155	(setq gnus-async-timer
	156	(run-with-idle-timer
	157	0.1 nil 'gnus-async-prefetch-article
	158	group next summary))))))))
eec82323 LMI	159
	160	(defun gnus-async-prefetch-article (group article summary &optional next)
	161	"Possibly prefetch several articles starting with ARTICLE."
	162	(if (not (gnus-buffer-live-p summary))
	163	(gnus-async-with-semaphore
16409b0b	164	(setq gnus-async-fetch-list nil))
eec82323 LMI	165	(when (and gnus-asynchronous
	166	(gnus-alive-p))
	167	(when next
	168	(gnus-async-with-semaphore
16409b0b	169	(pop gnus-async-fetch-list)))
eec82323	170	(let ((do-fetch next)
16409b0b	171	(do-message t)) ;(eq major-mode 'gnus-summary-mode)))
eec82323 LMI	172	(when (and (gnus-group-asynchronous-p group)
	173	(gnus-buffer-live-p summary)
	174	(or (not next)
	175	gnus-async-fetch-list))
	176	(gnus-async-with-semaphore
16409b0b GM	177	(unless next
	178	(setq do-fetch (not gnus-async-fetch-list))
	179	;; Nix out any outstanding requests.
	180	(setq gnus-async-fetch-list nil)
	181	;; Fill in the new list.
	182	(let ((n gnus-use-article-prefetch)
	183	(data (gnus-data-find-list article))
	184	d)
	185	(while (and (setq d (pop data))
	186	(if (numberp n)
	187	(natnump (decf n))
	188	n))
	189	(unless (or (gnus-async-prefetched-article-entry
	190	group (setq article (gnus-data-number d)))
	191	(not (natnump article))
	192	(not (funcall gnus-async-prefetch-article-p d)))
	193	;; Not already fetched -- so we add it to the list.
	194	(push article gnus-async-fetch-list)))
	195	(setq gnus-async-fetch-list
	196	(nreverse gnus-async-fetch-list))))
	197
	198	(when do-fetch
	199	(setq article (car gnus-async-fetch-list))))
eec82323 LMI	200
	201	(when (and do-fetch article)
	202	;; We want to fetch some more articles.
	203	(save-excursion
	204	(set-buffer summary)
	205	(let (mark)
	206	(gnus-async-set-buffer)
	207	(goto-char (point-max))
	208	(setq mark (point-marker))
	209	(let ((nnheader-callback-function
	210	(gnus-make-async-article-function
	211	group article mark summary next))
	212	(nntp-server-buffer
	213	(get-buffer gnus-async-prefetch-article-buffer)))
	214	(when do-message
	215	(gnus-message 9 "Prefetching article %d in group %s"
	216	article group))
16409b0b GM	217	(setq gnus-async-current-prefetch-group group)
16409b0b GM	218	(setq gnus-async-current-prefetch-article article)
eec82323 LMI	219	(gnus-request-article article group))))))))))
	220
	221	(defun gnus-make-async-article-function (group article mark summary next)
	222	"Return a callback function."
	223	`(lambda (arg)
16409b0b GM	224	(gnus-async-article-callback arg ,group ,article ,mark ,summary ,next)))
	225
	226	(defun gnus-async-article-callback (arg group article mark summary next)
	227	"Function called when an async article is done being fetched."
	228	(save-excursion
	229	(setq gnus-async-current-prefetch-article nil)
	230	(when arg
	231	(gnus-async-set-buffer)
	232	(gnus-async-with-semaphore
	233	(setq
	234	gnus-async-article-alist
	235	(cons (list (intern (format "%s-%d" group article)
	236	gnus-async-hashtb)
	237	mark (set-marker (make-marker) (point-max))
	238	group article)
	239	gnus-async-article-alist))))
	240	(if (not (gnus-buffer-live-p summary))
	241	(gnus-async-with-semaphore
	242	(setq gnus-async-fetch-list nil))
	243	(gnus-async-prefetch-article group next summary t))))
eec82323 LMI	244
	245	(defun gnus-async-unread-p (data)
	246	"Return non-nil if DATA represents an unread article."
	247	(gnus-data-unread-p data))
	248
	249	(defun gnus-async-request-fetched-article (group article buffer)
	250	"See whether we have ARTICLE from GROUP and put it in BUFFER."
	251	(when (numberp article)
16409b0b GM	252	(when (and (equal group gnus-async-current-prefetch-group)
	253	(eq article gnus-async-current-prefetch-article))
	254	(gnus-async-wait-for-article article))
eec82323 LMI	255	(let ((entry (gnus-async-prefetched-article-entry group article)))
	256	(when entry
	257	(save-excursion
	258	(gnus-async-set-buffer)
	259	(copy-to-buffer buffer (cadr entry) (caddr entry))
	260	;; Remove the read article from the prefetch buffer.
	261	(when (memq 'read gnus-prefetched-article-deletion-strategy)
16409b0b	262	(gnus-async-delete-prefetched-entry entry))
eec82323 LMI	263	t)))))
eec82323 LMI	264
16409b0b GM	265	(defun gnus-async-wait-for-article (article)
	266	"Wait until ARTICLE is no longer the currently-being-fetched article."
	267	(save-excursion
	268	(gnus-async-set-buffer)
	269	(let ((proc (nntp-find-connection (current-buffer)))
	270	(nntp-server-buffer (current-buffer))
	271	(nntp-have-messaged nil)
	272	(tries 0))
01c52d31 MB	273	(when proc
	274	(condition-case nil
	275	;; FIXME: we could stop waiting after some
	276	;; timeout, but this is the wrong place to do it.
	277	;; rather than checking time-spent-waiting, we
	278	;; should check time-since-last-output, which
	279	;; needs to be done in nntp.el.
	280	(while (eq article gnus-async-current-prefetch-article)
	281	(incf tries)
	282	(when (nntp-accept-process-output proc)
	283	(setq tries 0))
	284	(when (and (not nntp-have-messaged)
	285	(= tries 3))
	286	(gnus-message 5 "Waiting for async article...")
	287	(setq nntp-have-messaged t)))
	288	(quit
	289	;; if the user interrupted on a slow/hung connection,
	290	;; do something friendly.
	291	(when (> tries 3)
	292	(setq gnus-async-current-prefetch-article nil))
	293	(signal 'quit nil)))
	294	(when nntp-have-messaged
	295	(gnus-message 5 ""))))))
16409b0b GM	296
16409b0b GM	297	(defun gnus-async-delete-prefetched-entry (entry)
eec82323 LMI	298	"Delete ENTRY from buffer and alist."
	299	(ignore-errors
	300	(delete-region (cadr entry) (caddr entry))
	301	(set-marker (cadr entry) nil)
	302	(set-marker (caddr entry) nil))
	303	(gnus-async-with-semaphore
16409b0b GM	304	(setq gnus-async-article-alist
16409b0b GM	305	(delq entry gnus-async-article-alist))))
eec82323 LMI	306
	307	(defun gnus-async-prefetch-remove-group (group)
	308	"Remove all articles belonging to GROUP from the prefetch buffer."
	309	(when (and (gnus-group-asynchronous-p group)
	310	(memq 'exit gnus-prefetched-article-deletion-strategy))
01c52d31 MB	311	(save-excursion
	312	(gnus-async-set-buffer)
	313	(dolist (entry gnus-async-article-alist)
	314	(when (equal group (nth 3 entry))
	315	(gnus-async-delete-prefetched-entry entry))))))
eec82323 LMI	316
eec82323 LMI	317	(defun gnus-async-prefetched-article-entry (group article)
e7f767c2	318	"Return the entry for ARTICLE in GROUP if it has been prefetched."
6748645f LMI	319	(let ((entry (save-excursion
	320	(gnus-async-set-buffer)
	321	(assq (intern (format "%s-%d" group article)
16409b0b	322	gnus-async-hashtb)
6748645f	323	gnus-async-article-alist))))
eec82323 LMI	324	;; Perhaps something has emptied the buffer?
	325	(if (and entry
	326	(= (cadr entry) (caddr entry)))
	327	(progn
	328	(ignore-errors
	329	(set-marker (cadr entry) nil)
	330	(set-marker (caddr entry) nil))
	331	(setq gnus-async-article-alist
	332	(delq entry gnus-async-article-alist))
	333	nil)
	334	entry)))
	335
	336	;;;
	337	;;; Header prefetch
	338	;;;
	339
	340	(defun gnus-async-prefetch-headers (group)
	341	"Prefetch the headers for group GROUP."
	342	(save-excursion
	343	(let (unread)
	344	(when (and gnus-use-header-prefetch
	345	gnus-asynchronous
	346	(gnus-group-asynchronous-p group)
	347	(listp gnus-async-header-prefetched)
	348	(setq unread (gnus-list-of-unread-articles group)))
	349	;; Mark that a fetch is in progress.
	350	(setq gnus-async-header-prefetched t)
	351	(nnheader-set-temp-buffer gnus-async-prefetch-headers-buffer t)
	352	(erase-buffer)
	353	(let ((nntp-server-buffer (current-buffer))
	354	(nnheader-callback-function
	355	`(lambda (arg)
	356	(setq gnus-async-header-prefetched
	357	,(cons group unread)))))
	358	(gnus-retrieve-headers unread group gnus-fetch-old-headers))))))
	359
	360	(defun gnus-async-retrieve-fetched-headers (articles group)
	361	"See whether we have prefetched headers."
	362	(when (and gnus-use-header-prefetch
	363	(gnus-group-asynchronous-p group)
	364	(listp gnus-async-header-prefetched)
	365	(equal group (car gnus-async-header-prefetched))
	366	(equal articles (cdr gnus-async-header-prefetched)))
	367	(save-excursion
	368	(nnheader-set-temp-buffer gnus-async-prefetch-headers-buffer t)
	369	(nntp-decode-text)
	370	(copy-to-buffer nntp-server-buffer (point-min) (point-max))
	371	(erase-buffer)
	372	(setq gnus-async-header-prefetched nil)
	373	t)))
	374
	375	(provide 'gnus-async)
	376
ab5796a9	377	;;; arch-tag: fee61de5-3ea2-4de6-8578-2f90ce89391d
eec82323	378	;;; gnus-async.el ends here