1 ;;; gnus-cache.el --- cache interface for Gnus
3 ;; Copyright (C) 1995 Free Software Foundation, Inc.
5 ;; Author: Lars Magne Ingebrigtsen <larsi@ifi.uio.no>
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 2, or (at your option)
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; see the file COPYING. If not, write to the
22 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
23 ;; Boston, MA 02111-1307, USA.
31 (defvar gnus-cache-directory (concat gnus-article-save-directory "cache/")
32 "*The directory where cached articles will be stored.")
34 (defvar gnus-cache-enter-articles '(ticked dormant)
35 "*Classes of articles to enter into the cache.")
37 (defvar gnus-cache-remove-articles '(read)
38 "*Classes of articles to remove from the cache.")
42 (defvar gnus-cache-buffer nil)
46 (defun gnus-cache-change-buffer (group)
47 (and gnus-cache-buffer
48 ;; see if the current group's overview cache has been loaded
49 (or (string= group (car gnus-cache-buffer))
50 ;; another overview cache is current, save it
51 (gnus-cache-save-buffers)))
52 ;; if gnus-cache buffer is nil, create it
54 ;; create cache buffer
56 (setq gnus-cache-buffer
58 (set-buffer (get-buffer-create " *gnus-cache-overview*"))))
59 (buffer-disable-undo (current-buffer))
60 ;; insert the contents of this groups cache overview
62 (let ((file (gnus-cache-file-name group ".overview")))
63 (and (file-exists-p file)
64 (insert-file-contents file)))
65 ;; we have a fresh (empty/just loaded) buffer,
66 ;; mark it as unmodified to save a redundant write later.
67 (set-buffer-modified-p nil))))
70 (defun gnus-cache-save-buffers ()
71 ;; save the overview buffer if it exists and has been modified
72 ;; delete empty cache subdirectories
73 (if (null gnus-cache-buffer)
75 (let ((buffer (cdr gnus-cache-buffer))
76 (overview-file (gnus-cache-file-name
77 (car gnus-cache-buffer) ".overview")))
78 ;; write the overview only if it was modified
79 (if (buffer-modified-p buffer)
82 (if (> (buffer-size) 0)
83 ;; non-empty overview, write it out
85 (gnus-make-directory (file-name-directory overview-file))
86 (write-region (point-min) (point-max)
87 overview-file nil 'quietly))
88 ;; empty overview file, remove it
89 (and (file-exists-p overview-file)
90 (delete-file overview-file))
91 ;; if possible, remove group's cache subdirectory
93 ;; FIXME: we can detect the error type and warn the user
94 ;; of any inconsistencies (articles w/o nov entries?).
95 ;; for now, just be conservative...delete only if safe -- sj
96 (delete-directory (file-name-directory overview-file))
98 ;; kill the buffer, it's either unmodified or saved
99 (gnus-kill-buffer buffer)
100 (setq gnus-cache-buffer nil))))
103 ;; Return whether an article is a member of a class.
104 (defun gnus-cache-member-of-class (class ticked dormant unread)
105 (or (and ticked (memq 'ticked class))
106 (and dormant (memq 'dormant class))
107 (and unread (memq 'unread class))
108 (and (not unread) (memq 'read class))))
110 (defun gnus-cache-file-name (group article)
111 (concat (file-name-as-directory gnus-cache-directory)
112 (if (gnus-use-long-file-name 'not-cache)
114 (let ((group (concat group "")))
115 (if (string-match ":" group)
116 (aset group (match-beginning 0) ?/))
117 (gnus-replace-chars-in-string group ?. ?/)))
118 "/" (if (stringp article) article (int-to-string article))))
120 (defun gnus-cache-possibly-enter-article
121 (group article headers ticked dormant unread)
122 (let ((number (mail-header-number headers))
124 (if (or (not (vectorp headers)) ; This might be a dummy article.
125 (< number 0) ; Reffed article from other group.
126 (not (gnus-cache-member-of-class
127 gnus-cache-enter-articles ticked dormant unread))
128 (file-exists-p (setq file (gnus-cache-file-name group article))))
130 ;; Possibly create the cache directory.
131 (or (file-exists-p (setq dir (file-name-directory file)))
132 (gnus-make-directory dir))
133 ;; Save the article in the cache.
134 (if (file-exists-p file)
135 t ; The article already is saved, so we end here.
136 (let ((gnus-use-cache nil))
137 (gnus-summary-select-article))
139 (set-buffer gnus-article-buffer)
142 (write-region (point-min) (point-max) file nil 'quiet))
143 (gnus-cache-change-buffer group)
144 (set-buffer (cdr gnus-cache-buffer))
145 (goto-char (point-max))
147 (while (condition-case ()
149 (> (read (current-buffer)) number))
151 ;; The line was malformed, so we just remove it!!
159 (if (< (read (current-buffer)) number)
164 ;; [number subject from date id references chars lines xref]
165 (insert (format "%s\t%s\t%s\t%s\t%s\t%s\t%s\t%s\t%s\t\n"
166 (mail-header-number headers)
167 (mail-header-subject headers)
168 (mail-header-from headers)
169 (mail-header-date headers)
170 (mail-header-id headers)
171 (or (mail-header-references headers) "")
172 (or (mail-header-chars headers) "")
173 (or (mail-header-lines headers) "")
174 (or (mail-header-xref headers) ""))))
177 (defun gnus-cache-enter-remove-article (article)
178 (setq gnus-cache-removable-articles
179 (cons article gnus-cache-removable-articles)))
181 (defsubst gnus-cache-possibly-remove-article
182 (article ticked dormant unread)
183 (let ((file (gnus-cache-file-name gnus-newsgroup-name article)))
184 (if (or (not (file-exists-p file))
185 (not (gnus-cache-member-of-class
186 gnus-cache-remove-articles ticked dormant unread)))
190 (set-buffer (cdr gnus-cache-buffer))
191 (goto-char (point-min))
192 (if (or (looking-at (concat (int-to-string article) "\t"))
193 (search-forward (concat "\n" (int-to-string article) "\t")
195 (delete-region (progn (beginning-of-line) (point))
196 (progn (forward-line 1) (point))))))))
198 (defun gnus-cache-possibly-remove-articles ()
199 (let ((articles gnus-cache-removable-articles)
200 (cache-articles (gnus-cache-articles-in-group gnus-newsgroup-name))
202 (gnus-cache-change-buffer gnus-newsgroup-name)
204 (setq article (car articles)
205 articles (cdr articles))
206 (if (memq article cache-articles)
207 ;; The article was in the cache, so we see whether we are
208 ;; supposed to remove it from the cache.
209 (gnus-cache-possibly-remove-article
210 article (memq article gnus-newsgroup-marked)
211 (memq article gnus-newsgroup-dormant)
212 (or (memq article gnus-newsgroup-unreads)
213 (memq article gnus-newsgroup-unselected))))))
214 ;; the overview file might have been modified, save it
215 ;; safe because we're only called at group exit anyway
216 (gnus-cache-save-buffers))
219 (defun gnus-cache-request-article (article group)
220 (let ((file (gnus-cache-file-name group article)))
221 (if (not (file-exists-p file))
224 ;; There may be some overlays that we have to kill...
226 (let ((overlays (overlays-at (point-min))))
228 (delete-overlay (car overlays))
229 (setq overlays (cdr overlays))))
231 (insert-file-contents file)
234 (defun gnus-cache-articles-in-group (group)
235 (let ((dir (file-name-directory (gnus-cache-file-name group 1)))
237 (if (not (file-exists-p dir))
239 (setq articles (directory-files dir nil "^[0-9]+$" t))
242 (sort (mapcar (function (lambda (name)
243 (string-to-int name)))
247 (defun gnus-cache-active-articles (group)
248 (let ((articles (gnus-cache-articles-in-group group)))
250 (cons (car articles) (gnus-last-element articles)))))
252 (defun gnus-cache-possibly-alter-active (group active)
253 (let ((cache-active (gnus-cache-active-articles group)))
254 (and cache-active (< (car cache-active) (car active))
255 (setcar active (car cache-active)))
256 (and cache-active (> (cdr cache-active) (cdr active))
257 (setcdr active (cdr cache-active)))))
259 (defun gnus-cache-retrieve-headers (articles group)
260 (let* ((cached (gnus-cache-articles-in-group group))
261 (articles (gnus-sorted-complement articles cached))
262 (cache-file (gnus-cache-file-name group ".overview"))
264 (let ((gnus-use-cache nil))
265 (setq type (and articles (gnus-retrieve-headers articles group))))
266 (gnus-cache-save-buffers)
268 (cond ((not (file-exists-p cache-file))
271 (set-buffer nntp-server-buffer)
273 (insert-file-contents cache-file)
276 (gnus-cache-braid-nov group cached)
279 (gnus-cache-braid-heads group cached)
282 (defun gnus-cache-braid-nov (group cached)
283 (let ((cache-buf (get-buffer-create " *gnus-cache*"))
285 (gnus-cache-save-buffers)
287 (set-buffer cache-buf)
288 (buffer-disable-undo (current-buffer))
290 (insert-file-contents (gnus-cache-file-name group ".overview"))
291 (goto-char (point-min))
293 (goto-char (point-min)))
294 (set-buffer nntp-server-buffer)
295 (goto-char (point-min))
297 (while (and (not (eobp))
298 (< (read (current-buffer)) (car cached)))
302 (set-buffer cache-buf)
303 (if (search-forward (concat "\n" (int-to-string (car cached)) "\t")
305 (setq beg (progn (beginning-of-line) (point))
306 end (progn (end-of-line) (point)))
308 (if beg (progn (insert-buffer-substring cache-buf beg end)
310 (setq cached (cdr cached)))
311 (kill-buffer cache-buf)))
313 (defun gnus-cache-braid-heads (group cached)
314 (let ((cache-buf (get-buffer-create " *gnus-cache*")))
316 (set-buffer cache-buf)
317 (buffer-disable-undo (current-buffer))
319 (set-buffer nntp-server-buffer)
320 (goto-char (point-min))
322 (while (and (not (eobp))
323 (looking-at "2.. +\\([0-9]+\\) ")
324 (< (progn (goto-char (match-beginning 1))
325 (read (current-buffer)))
327 (search-forward "\n.\n" nil 'move))
330 (set-buffer cache-buf)
332 (insert-file-contents (gnus-cache-file-name group (car cached)))
333 (goto-char (point-min))
334 (insert "220 " (int-to-string (car cached)) " Article retrieved.\n")
335 (search-forward "\n\n" nil 'move)
336 (delete-region (point) (point-max))
339 (insert-buffer-substring cache-buf)
340 (setq cached (cdr cached)))
341 (kill-buffer cache-buf)))
343 (defun gnus-jog-cache ()
344 "Go through all groups and put the articles into the cache."
346 (let ((newsrc (cdr gnus-newsrc-alist))
347 (gnus-cache-enter-articles '(unread))
348 (gnus-mark-article-hook nil)
350 (gnus-large-newsgroup nil))
352 (gnus-summary-read-group (car (car newsrc)))
353 (if (not (eq major-mode 'gnus-summary-mode))
355 (while gnus-newsgroup-unreads
356 (gnus-summary-select-article t t nil (car gnus-newsgroup-unreads))
357 (setq gnus-newsgroup-unreads (cdr gnus-newsgroup-unreads)))
358 (kill-buffer (current-buffer)))
359 (setq newsrc (cdr newsrc)))))
361 (provide 'gnus-cache)
363 ;;; gnus-cache.el ends here