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

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

;; Copyright (C) 1996-2011 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."
  :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))
    (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)))

(eval-when-compile
  (autoload 'gnus-html-prefetch-images "gnus-html"))

(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))
	  ;; 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 (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))
    (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
Commit	Line	Data
eec82323	1	;;; gnus-async.el --- asynchronous support for Gnus
e84b4b86	2
73b0cd50	3	;; Copyright (C) 1996-2011 Free Software Foundation, Inc.
eec82323	4
6748645f	5	;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
eec82323 LMI	6	;; Keywords: news
	7
	8	;; This file is part of GNU Emacs.
	9
5e809f55	10	;; GNU Emacs is free software: you can redistribute it and/or modify
eec82323	11	;; it under the terms of the GNU General Public License as published by
5e809f55 GM	12	;; the Free Software Foundation, either version 3 of the License, or
5e809f55 GM	13	;; (at your option) any later version.
eec82323 LMI	14
	15	;; GNU Emacs is distributed in the hope that it will be useful,
	16	;; but WITHOUT ANY WARRANTY; without even the implied warranty of
5e809f55	17	;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
eec82323 LMI	18	;; GNU General Public License for more details.
	19
	20	;; You should have received a copy of the GNU General Public License
5e809f55	21	;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
eec82323 LMI	22
	23	;;; Commentary:
	24
	25	;;; Code:
	26
5ab7173c RS	27	(eval-when-compile (require 'cl))
5ab7173c RS	28
eec82323 LMI	29	(require 'gnus)
	30	(require 'gnus-sum)
	31	(require 'nntp)
	32
	33	(defgroup gnus-asynchronous nil
	34	"Support for asynchronous operations."
	35	:group 'gnus)
	36
eec82323 LMI	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)
16409b0b GM	43	(const :tag "all" t)
16409b0b GM	44	(integer :tag "some" 0)))
eec82323	45
23f87bed MB	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
	50	:type 'boolean)
	51
eec82323 LMI	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
	57	from that group."
	58	:group 'gnus-asynchronous
	59	:type '(set (const read) (const exit)))
	60
	61	(defcustom gnus-use-header-prefetch nil
	62	"*If non-nil, prefetch the headers to the next group."
	63	:group 'gnus-asynchronous
	64	:type 'boolean)
	65
	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
	71	:type 'function)
	72
b1992461 KY	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
	76	that was fetched."
	77	:group 'gnus-asynchronous
	78	:type 'function)
	79
eec82323 LMI	80	;;; Internal variables.
	81
	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)
16409b0b GM	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)
eec82323 LMI	90
	91	(defvar gnus-async-prefetch-headers-buffer " Async Prefetch Headers")
	92	(defvar gnus-async-header-prefetched nil)
	93
	94	;;; Utility functions.
	95
	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)))
	99
	100	;;; Somewhat bogus semaphores.
	101
	102	(defun gnus-async-get-semaphore (semaphore)
	103	"Wait until SEMAPHORE is released."
	104	(while (/= (length (nconc (symbol-value semaphore) (list nil))) 2)
	105	(sleep-for 1)))
	106
	107	(defun gnus-async-release-semaphore (semaphore)
	108	"Release SEMAPHORE."
	109	(setcdr (symbol-value semaphore) nil))
	110
	111	(defmacro gnus-async-with-semaphore (&rest forms)
	112	`(unwind-protect
	113	(progn
	114	(gnus-async-get-semaphore 'gnus-async-article-semaphore)
	115	,@forms)
	116	(gnus-async-release-semaphore 'gnus-async-article-semaphore)))
	117
16409b0b GM	118	(put 'gnus-async-with-semaphore 'lisp-indent-function 0)
16409b0b GM	119	(put 'gnus-async-with-semaphore 'edebug-form-spec '(body))
eec82323 LMI	120
	121	;;;
	122	;;; Article prefetch
	123	;;;
	124
	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)
16409b0b GM	129	(setq gnus-async-hashtb nil
16409b0b GM	130	gnus-async-article-alist nil
eec82323 LMI	131	gnus-async-header-prefetched nil))
	132
	133	(defun gnus-async-set-buffer ()
6748645f	134	(nnheader-set-temp-buffer gnus-async-prefetch-article-buffer t)
16409b0b GM	135	(unless gnus-async-hashtb
16409b0b GM	136	(setq gnus-async-hashtb (gnus-make-hashtable 1023))))
eec82323 LMI	137
	138	(defun gnus-async-halt-prefetch ()
	139	"Stop prefetching."
	140	(setq gnus-async-fetch-list nil))
	141
	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)
	145	gnus-asynchronous
	146	(gnus-group-asynchronous-p group))
20a673b2	147	(with-current-buffer gnus-summary-buffer
eec82323 LMI	148	(let ((next (caadr (gnus-data-find-list article))))
	149	(when next
	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
	153	;; buffer display.
	154	(gnus-async-prefetch-article group next summary)
16409b0b GM	155	(when gnus-async-timer
	156	(ignore-errors
	157	(nnheader-cancel-timer 'gnus-async-timer)))
	158	(setq gnus-async-timer
	159	(run-with-idle-timer
	160	0.1 nil 'gnus-async-prefetch-article
	161	group next summary))))))))
eec82323 LMI	162
	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
16409b0b	167	(setq gnus-async-fetch-list nil))
eec82323 LMI	168	(when (and gnus-asynchronous
	169	(gnus-alive-p))
	170	(when next
	171	(gnus-async-with-semaphore
16409b0b	172	(pop gnus-async-fetch-list)))
eec82323	173	(let ((do-fetch next)
16409b0b	174	(do-message t)) ;(eq major-mode 'gnus-summary-mode)))
eec82323 LMI	175	(when (and (gnus-group-asynchronous-p group)
	176	(gnus-buffer-live-p summary)
	177	(or (not next)
	178	gnus-async-fetch-list))
	179	(gnus-async-with-semaphore
16409b0b GM	180	(unless next
	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))
	187	d)
	188	(while (and (setq d (pop data))
	189	(if (numberp n)
	190	(natnump (decf n))
	191	n))
	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))))
	200
	201	(when do-fetch
	202	(setq article (car gnus-async-fetch-list))))
eec82323 LMI	203
	204	(when (and do-fetch article)
	205	;; We want to fetch some more articles.
20a673b2	206	(with-current-buffer summary
eec82323 LMI	207	(let (mark)
	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))
	214	(nntp-server-buffer
	215	(get-buffer gnus-async-prefetch-article-buffer)))
	216	(when do-message
	217	(gnus-message 9 "Prefetching article %d in group %s"
	218	article group))
16409b0b GM	219	(setq gnus-async-current-prefetch-group group)
16409b0b GM	220	(setq gnus-async-current-prefetch-article article)
eec82323 LMI	221	(gnus-request-article article group))))))))))
	222
	223	(defun gnus-make-async-article-function (group article mark summary next)
	224	"Return a callback function."
	225	`(lambda (arg)
16409b0b GM	226	(gnus-async-article-callback arg ,group ,article ,mark ,summary ,next)))
16409b0b GM	227
16ec6ca4 KY	228	(eval-when-compile
	229	(autoload 'gnus-html-prefetch-images "gnus-html"))
	230
16409b0b GM	231	(defun gnus-async-article-callback (arg group article mark summary next)
	232	"Function called when an async article is done being fetched."
	233	(save-excursion
	234	(setq gnus-async-current-prefetch-article nil)
	235	(when arg
	236	(gnus-async-set-buffer)
724d30be KY	237	(save-excursion
	238	(save-restriction
	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
b1992461	244	(funcall gnus-async-post-fetch-function summary))))
16409b0b GM	245	(gnus-async-with-semaphore
	246	(setq
	247	gnus-async-article-alist
	248	(cons (list (intern (format "%s-%d" group article)
	249	gnus-async-hashtb)
	250	mark (set-marker (make-marker) (point-max))
	251	group article)
	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))))
eec82323 LMI	257
	258	(defun gnus-async-unread-p (data)
	259	"Return non-nil if DATA represents an unread article."
	260	(gnus-data-unread-p data))
	261
	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)
16409b0b GM	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))
eec82323 LMI	268	(let ((entry (gnus-async-prefetched-article-entry group article)))
	269	(when entry
	270	(save-excursion
	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)
16409b0b	275	(gnus-async-delete-prefetched-entry entry))
eec82323 LMI	276	t)))))
eec82323 LMI	277
16409b0b GM	278	(defun gnus-async-wait-for-article (article)
	279	"Wait until ARTICLE is no longer the currently-being-fetched article."
	280	(save-excursion
	281	(gnus-async-set-buffer)
	282	(let ((proc (nntp-find-connection (current-buffer)))
	283	(nntp-server-buffer (current-buffer))
	284	(nntp-have-messaged nil)
	285	(tries 0))
01c52d31 MB	286	(when proc
	287	(condition-case 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)
	294	(incf tries)
	295	(when (nntp-accept-process-output proc)
	296	(setq tries 0))
	297	(when (and (not nntp-have-messaged)
	298	(= tries 3))
	299	(gnus-message 5 "Waiting for async article...")
	300	(setq nntp-have-messaged t)))
	301	(quit
	302	;; if the user interrupted on a slow/hung connection,
	303	;; do something friendly.
	304	(when (> tries 3)
	305	(setq gnus-async-current-prefetch-article nil))
	306	(signal 'quit nil)))
	307	(when nntp-have-messaged
	308	(gnus-message 5 ""))))))
16409b0b GM	309
16409b0b GM	310	(defun gnus-async-delete-prefetched-entry (entry)
eec82323 LMI	311	"Delete ENTRY from buffer and alist."
	312	(ignore-errors
	313	(delete-region (cadr entry) (caddr entry))
	314	(set-marker (cadr entry) nil)
	315	(set-marker (caddr entry) nil))
	316	(gnus-async-with-semaphore
16409b0b	317	(setq gnus-async-article-alist
a3f57c41 G	318	(delq entry gnus-async-article-alist))
a3f57c41 G	319	(unintern (car entry) gnus-async-hashtb)))
eec82323 LMI	320
	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))
01c52d31 MB	325	(save-excursion
	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))))))
eec82323 LMI	330
eec82323 LMI	331	(defun gnus-async-prefetched-article-entry (group article)
e7f767c2	332	"Return the entry for ARTICLE in GROUP if it has been prefetched."
6748645f LMI	333	(let ((entry (save-excursion
6748645f LMI	334	(gnus-async-set-buffer)
a3f57c41 G	335	(assq (intern-soft (format "%s-%d" group article)
a3f57c41 G	336	gnus-async-hashtb)
6748645f	337	gnus-async-article-alist))))
eec82323 LMI	338	;; Perhaps something has emptied the buffer?
	339	(if (and entry
	340	(= (cadr entry) (caddr entry)))
	341	(progn
	342	(ignore-errors
	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))
	347	nil)
	348	entry)))
	349
	350	;;;
	351	;;; Header prefetch
	352	;;;
	353
	354	(defun gnus-async-prefetch-headers (group)
	355	"Prefetch the headers for group GROUP."
	356	(save-excursion
	357	(let (unread)
	358	(when (and gnus-use-header-prefetch
	359	gnus-asynchronous
	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)
	366	(erase-buffer)
	367	(let ((nntp-server-buffer (current-buffer))
	368	(nnheader-callback-function
	369	`(lambda (arg)
	370	(setq gnus-async-header-prefetched
	371	,(cons group unread)))))
	372	(gnus-retrieve-headers unread group gnus-fetch-old-headers))))))
	373
	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)))
	381	(save-excursion
	382	(nnheader-set-temp-buffer gnus-async-prefetch-headers-buffer t)
	383	(nntp-decode-text)
	384	(copy-to-buffer nntp-server-buffer (point-min) (point-max))
	385	(erase-buffer)
	386	(setq gnus-async-header-prefetched nil)
	387	t)))
	388
	389	(provide 'gnus-async)
	390
	391	;;; gnus-async.el ends here