1 ;;; gnus-cache.el --- cache interface for Gnus
2 ;; Copyright (C) 1995 Free Software Foundation, Inc.
4 ;; Author: Lars Magne Ingebrigtsen <larsi@ifi.uio.no>
7 ;; This file is part of GNU Emacs.
9 ;; GNU Emacs is free software; you can redistribute it and/or modify
10 ;; it under the terms of the GNU General Public License as published by
11 ;; the Free Software Foundation; either version 2, or (at your option)
14 ;; GNU Emacs is distributed in the hope that it will be useful,
15 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
16 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 ;; GNU General Public License for more details.
19 ;; You should have received a copy of the GNU General Public License
20 ;; along with GNU Emacs; see the file COPYING. If not, write to
21 ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
29 (defvar gnus-cache-directory (concat gnus-article-save-directory "cache/")
30 "*The directory where cached articles will be stored.")
32 (defvar gnus-cache-enter-articles '(ticked dormant)
33 "*Classes of articles to enter into the cache.")
35 (defvar gnus-cache-remove-articles '(read)
36 "*Classes of articles to remove from the cache.")
40 (defvar gnus-cache-buffer nil)
44 (defun gnus-cache-change-buffer (group)
45 (and gnus-cache-buffer
46 ;; see if the current group's overview cache has been loaded
47 (or (string= group (car gnus-cache-buffer))
48 ;; another overview cache is current, save it
49 (gnus-cache-save-buffers)))
50 ;; if gnus-cache buffer is nil, create it
52 ;; create cache buffer
54 (setq gnus-cache-buffer
56 (set-buffer (get-buffer-create " *gnus-cache-overview*"))))
57 (buffer-disable-undo (current-buffer))
58 ;; insert the contents of this groups cache overview
60 (let ((file (gnus-cache-file-name group ".overview")))
61 (and (file-exists-p file)
62 (insert-file-contents file)))
63 ;; we have a fresh (empty/just loaded) buffer,
64 ;; mark it as unmodified to save a redundant write later.
65 (set-buffer-modified-p nil))))
68 (defun gnus-cache-save-buffers ()
69 ;; save the overview buffer if it exists and has been modified
70 ;; delete empty cache subdirectories
71 (if (null gnus-cache-buffer)
73 (let ((buffer (cdr gnus-cache-buffer))
74 (overview-file (gnus-cache-file-name
75 (car gnus-cache-buffer) ".overview")))
76 ;; write the overview only if it was modified
77 (if (buffer-modified-p buffer)
80 (if (> (buffer-size) 0)
81 ;; non-empty overview, write it out
83 (gnus-make-directory (file-name-directory overview-file))
84 (write-region (point-min) (point-max)
85 overview-file nil 'quietly))
86 ;; empty overview file, remove it
87 (and (file-exists-p overview-file)
88 (delete-file overview-file))
89 ;; if possible, remove group's cache subdirectory
91 ;; FIXME: we can detect the error type and warn the user
92 ;; of any inconsistencies (articles w/o nov entries?).
93 ;; for now, just be conservative...delete only if safe -- sj
94 (delete-directory (file-name-directory overview-file))
96 ;; kill the buffer, it's either unmodified or saved
97 (gnus-kill-buffer buffer)
98 (setq gnus-cache-buffer nil))))
101 ;; Return whether an article is a member of a class.
102 (defun gnus-cache-member-of-class (class ticked dormant unread)
103 (or (and ticked (memq 'ticked class))
104 (and dormant (memq 'dormant class))
105 (and unread (memq 'unread class))
106 (and (not unread) (memq 'read class))))
108 (defun gnus-cache-file-name (group article)
109 (concat (file-name-as-directory gnus-cache-directory)
110 (if (gnus-use-long-file-name 'not-cache)
112 (let ((group (concat group "")))
113 (if (string-match ":" group)
114 (aset group (match-beginning 0) ?/))
115 (gnus-replace-chars-in-string group ?. ?/)))
116 "/" (if (stringp article) article (int-to-string article))))
118 (defun gnus-cache-possibly-enter-article
119 (group article headers ticked dormant unread)
120 (let ((number (mail-header-number headers))
122 (if (or (not (vectorp headers)) ; This might be a dummy article.
123 (< number 0) ; Reffed article from other group.
124 (not (gnus-cache-member-of-class
125 gnus-cache-enter-articles ticked dormant unread))
126 (file-exists-p (setq file (gnus-cache-file-name group article))))
128 ;; Possibly create the cache directory.
129 (or (file-exists-p (setq dir (file-name-directory file)))
130 (gnus-make-directory dir))
131 ;; Save the article in the cache.
132 (if (file-exists-p file)
133 t ; The article already is saved, so we end here.
134 (let ((gnus-use-cache nil))
135 (gnus-summary-select-article))
137 (set-buffer gnus-article-buffer)
140 (write-region (point-min) (point-max) file nil 'quiet))
141 (gnus-cache-change-buffer group)
142 (set-buffer (cdr gnus-cache-buffer))
143 (goto-char (point-max))
145 (while (condition-case ()
147 (> (read (current-buffer)) number))
149 ;; The line was malformed, so we just remove it!!
157 (if (< (read (current-buffer)) number)
162 ;; [number subject from date id references chars lines xref]
163 (insert (format "%s\t%s\t%s\t%s\t%s\t%s\t%s\t%s\t%s\t\n"
164 (mail-header-number headers)
165 (mail-header-subject headers)
166 (mail-header-from headers)
167 (mail-header-date headers)
168 (mail-header-id headers)
169 (or (mail-header-references headers) "")
170 (or (mail-header-chars headers) "")
171 (or (mail-header-lines headers) "")
172 (or (mail-header-xref headers) ""))))
175 (defun gnus-cache-enter-remove-article (article)
176 (setq gnus-cache-removeable-articles
177 (cons article gnus-cache-removeable-articles)))
179 (defsubst gnus-cache-possibly-remove-article
180 (article ticked dormant unread)
181 (let ((file (gnus-cache-file-name gnus-newsgroup-name article)))
182 (if (or (not (file-exists-p file))
183 (not (gnus-cache-member-of-class
184 gnus-cache-remove-articles ticked dormant unread)))
188 (set-buffer (cdr gnus-cache-buffer))
189 (goto-char (point-min))
190 (if (or (looking-at (concat (int-to-string article) "\t"))
191 (search-forward (concat "\n" (int-to-string article) "\t")
193 (delete-region (progn (beginning-of-line) (point))
194 (progn (forward-line 1) (point))))))))
196 (defun gnus-cache-possibly-remove-articles ()
197 (let ((articles gnus-cache-removeable-articles)
198 (cache-articles (gnus-cache-articles-in-group gnus-newsgroup-name))
200 (gnus-cache-change-buffer gnus-newsgroup-name)
202 (setq article (car articles)
203 articles (cdr articles))
204 (if (memq article cache-articles)
205 ;; The article was in the cache, so we see whether we are
206 ;; supposed to remove it from the cache.
207 (gnus-cache-possibly-remove-article
208 article (memq article gnus-newsgroup-marked)
209 (memq article gnus-newsgroup-dormant)
210 (or (memq article gnus-newsgroup-unreads)
211 (memq article gnus-newsgroup-unselected))))))
212 ;; the overview file might have been modified, save it
213 ;; safe because we're only called at group exit anyway
214 (gnus-cache-save-buffers))
217 (defun gnus-cache-request-article (article group)
218 (let ((file (gnus-cache-file-name group article)))
219 (if (not (file-exists-p file))
222 ;; There may be some overlays that we have to kill...
224 (let ((overlays (overlays-at (point-min))))
226 (delete-overlay (car overlays))
227 (setq overlays (cdr overlays))))
229 (insert-file-contents file)
232 (defun gnus-cache-articles-in-group (group)
233 (let ((dir (file-name-directory (gnus-cache-file-name group 1)))
235 (if (not (file-exists-p dir))
237 (setq articles (directory-files dir nil "^[0-9]+$" t))
240 (sort (mapcar (function (lambda (name)
241 (string-to-int name)))
245 (defun gnus-cache-active-articles (group)
246 (let ((articles (gnus-cache-articles-in-group group)))
248 (cons (car articles) (gnus-last-element articles)))))
250 (defun gnus-cache-possibly-alter-active (group active)
251 (let ((cache-active (gnus-cache-active-articles group)))
252 (and cache-active (< (car cache-active) (car active))
253 (setcar active (car cache-active)))
254 (and cache-active (> (cdr cache-active) (cdr active))
255 (setcdr active (cdr cache-active)))))
257 (defun gnus-cache-retrieve-headers (articles group)
258 (let* ((cached (gnus-cache-articles-in-group group))
259 (articles (gnus-sorted-complement articles cached))
260 (cache-file (gnus-cache-file-name group ".overview"))
262 (let ((gnus-use-cache nil))
263 (setq type (and articles (gnus-retrieve-headers articles group))))
264 (gnus-cache-save-buffers)
266 (cond ((not (file-exists-p cache-file))
269 (set-buffer nntp-server-buffer)
271 (insert-file-contents cache-file)
274 (gnus-cache-braid-nov group cached)
277 (gnus-cache-braid-heads group cached)
280 (defun gnus-cache-braid-nov (group cached)
281 (let ((cache-buf (get-buffer-create " *gnus-cache*"))
283 (gnus-cache-save-buffers)
285 (set-buffer cache-buf)
286 (buffer-disable-undo (current-buffer))
288 (insert-file-contents (gnus-cache-file-name group ".overview"))
289 (goto-char (point-min))
291 (goto-char (point-min)))
292 (set-buffer nntp-server-buffer)
293 (goto-char (point-min))
295 (while (and (not (eobp))
296 (< (read (current-buffer)) (car cached)))
300 (set-buffer cache-buf)
301 (if (search-forward (concat "\n" (int-to-string (car cached)) "\t")
303 (setq beg (progn (beginning-of-line) (point))
304 end (progn (end-of-line) (point)))
306 (if beg (progn (insert-buffer-substring cache-buf beg end)
308 (setq cached (cdr cached)))
309 (kill-buffer cache-buf)))
311 (defun gnus-cache-braid-heads (group cached)
312 (let ((cache-buf (get-buffer-create " *gnus-cache*")))
314 (set-buffer cache-buf)
315 (buffer-disable-undo (current-buffer))
317 (set-buffer nntp-server-buffer)
318 (goto-char (point-min))
320 (while (and (not (eobp))
321 (looking-at "2.. +\\([0-9]+\\) ")
322 (< (progn (goto-char (match-beginning 1))
323 (read (current-buffer)))
325 (search-forward "\n.\n" nil 'move))
328 (set-buffer cache-buf)
330 (insert-file-contents (gnus-cache-file-name group (car cached)))
331 (goto-char (point-min))
332 (insert "220 " (int-to-string (car cached)) " Article retrieved.\n")
333 (search-forward "\n\n" nil 'move)
334 (delete-region (point) (point-max))
337 (insert-buffer-substring cache-buf)
338 (setq cached (cdr cached)))
339 (kill-buffer cache-buf)))
341 (defun gnus-jog-cache ()
342 "Go through all groups and put the articles into the cache."
344 (let ((newsrc (cdr gnus-newsrc-alist))
345 (gnus-cache-enter-articles '(unread))
346 (gnus-mark-article-hook nil)
348 (gnus-large-newsgroup nil))
350 (gnus-summary-read-group (car (car newsrc)))
351 (if (not (eq major-mode 'gnus-summary-mode))
353 (while gnus-newsgroup-unreads
354 (gnus-summary-select-article t t nil (car gnus-newsgroup-unreads))
355 (setq gnus-newsgroup-unreads (cdr gnus-newsgroup-unreads)))
356 (kill-buffer (current-buffer)))
357 (setq newsrc (cdr newsrc)))))
359 (provide 'gnus-cache)
361 ;;; gnus-cache.el ends here