1 ;;; gnus-cache.el --- cache interface for Gnus
3 ;; Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003,
4 ;; 2004, 2005, 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
6 ;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
9 ;; This file is part of GNU Emacs.
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
13 ;; the Free Software Foundation, either version 3 of the License, or
14 ;; (at your option) any later version.
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.
21 ;; You should have received a copy of the GNU General Public License
22 ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
28 ;; For Emacs <22.2 and XEmacs.
30 (unless (fboundp 'declare-function) (defmacro declare-function (&rest r))))
32 (eval-when-compile (require 'cl))
38 (unless (fboundp 'gnus-agent-load-alist)
39 (defun gnus-agent-load-alist (group))))
41 (defcustom gnus-cache-active-file
42 (expand-file-name "active" gnus-cache-directory)
43 "*The cache active file."
47 (defcustom gnus-cache-enter-articles '(ticked dormant)
48 "Classes of articles to enter into the cache."
50 :type '(set (const ticked) (const dormant) (const unread) (const read)))
52 (defcustom gnus-cache-remove-articles '(read)
53 "Classes of articles to remove from the cache."
55 :type '(set (const ticked) (const dormant) (const unread) (const read)))
57 (defcustom gnus-cacheable-groups nil
58 "*Groups that match this regexp will be cached.
60 If you only want to cache your nntp groups, you could set this
61 variable to \"^nntp\".
63 If a group matches both gnus-cacheable-groups and gnus-uncacheable-groups
66 :type '(choice (const :tag "off" nil)
69 (defcustom gnus-uncacheable-groups nil
70 "*Groups that match this regexp will not be cached.
72 If you want to avoid caching your nnml groups, you could set this
73 variable to \"^nnml\".
75 If a group matches both gnus-cacheable-groups and gnus-uncacheable-groups
78 :type '(choice (const :tag "off" nil)
81 (defvar gnus-cache-overview-coding-system 'raw-text
82 "Coding system used on Gnus cache files.")
84 (defvar gnus-cache-coding-system 'raw-text
85 "Coding system used on Gnus cache files.")
89 ;;; Internal variables.
91 (defvar gnus-cache-removable-articles nil)
92 (defvar gnus-cache-buffer nil)
93 (defvar gnus-cache-active-hashtb nil)
94 (defvar gnus-cache-active-altered nil)
95 (defvar gnus-cache-total-fetched-hashtb nil)
97 (declare-function nnvirtual-find-group-art "nnvirtual" (group article))
99 (autoload 'nnml-generate-nov-databases-directory "nnml")
100 (autoload 'nnvirtual-find-group-art "nnvirtual")
104 ;;; Functions called from Gnus.
106 (defun gnus-cache-open ()
107 "Initialize the cache."
108 (when (or (file-exists-p gnus-cache-directory)
110 (not (eq gnus-use-cache 'passive))))
111 (gnus-cache-read-active)))
113 ;; Complexities of byte-compiling make this kludge necessary. Eeek.
115 (gnus-add-shutdown 'gnus-cache-close 'gnus))
117 (defun gnus-cache-close ()
118 "Shut down the cache."
119 (gnus-cache-write-active)
120 (gnus-cache-save-buffers)
121 (setq gnus-cache-active-hashtb nil))
123 (defun gnus-cache-save-buffers ()
124 ;; save the overview buffer if it exists and has been modified
125 ;; delete empty cache subdirectories
126 (when gnus-cache-buffer
127 (let ((buffer (cdr gnus-cache-buffer))
128 (overview-file (gnus-cache-file-name
129 (car gnus-cache-buffer) ".overview")))
130 ;; write the overview only if it was modified
131 (when (and (buffer-live-p buffer) (buffer-modified-p buffer))
132 (with-current-buffer buffer
133 (if (> (buffer-size) 0)
134 ;; Non-empty overview, write it to a file.
135 (let ((coding-system-for-write
136 gnus-cache-overview-coding-system))
137 (gnus-write-buffer overview-file))
138 (let ((file-name-coding-system nnmail-pathname-coding-system))
139 ;; Empty overview file, remove it
140 (when (file-exists-p overview-file)
141 (delete-file overview-file))
142 ;; If possible, remove group's cache subdirectory.
144 ;; FIXME: we can detect the error type and warn the user
145 ;; of any inconsistencies (articles w/o nov entries?).
146 ;; for now, just be conservative...delete only if safe -- sj
147 (delete-directory (file-name-directory overview-file))
150 (gnus-cache-update-overview-total-fetched-for
151 (car gnus-cache-buffer) overview-file)))
152 ;; Kill the buffer -- it's either unmodified or saved.
153 (gnus-kill-buffer buffer)
154 (setq gnus-cache-buffer nil))))
156 (defun gnus-cache-possibly-enter-article
157 (group article ticked dormant unread &optional force)
158 (when (and (or force (not (eq gnus-use-cache 'passive)))
160 (> article 0)) ; This might be a dummy article.
161 (let ((number article)
162 file headers lines-chars
163 (file-name-coding-system nnmail-pathname-coding-system))
164 ;; If this is a virtual group, we find the real group.
165 (when (gnus-virtual-group-p group)
166 (let ((result (nnvirtual-find-group-art
167 (gnus-group-real-name group) article)))
168 (setq group (car result)
169 number (cdr result))))
171 (> number 0) ; Reffed article.
173 (and (gnus-cache-fully-p group)
174 (gnus-cache-member-of-class
175 gnus-cache-enter-articles ticked dormant unread)))
176 (not (file-exists-p (setq file (gnus-cache-file-name
178 ;; Possibly create the cache directory.
179 (gnus-make-directory (file-name-directory file))
180 ;; Save the article in the cache.
181 (if (file-exists-p file)
182 t ; The article already is saved.
183 (with-current-buffer nntp-server-buffer
185 (let ((gnus-use-cache nil)
186 (gnus-article-decode-hook nil))
187 (gnus-request-article-this-buffer number group))
188 (when (> (buffer-size) 0)
189 (let ((coding-system-for-write gnus-cache-coding-system))
190 (gnus-write-buffer file)
191 (gnus-cache-update-file-total-fetched-for group file))
192 (setq lines-chars (nnheader-get-lines-and-char))
193 (nnheader-remove-body)
194 (setq headers (nnheader-parse-naked-head))
195 (mail-header-set-number headers number)
196 (mail-header-set-lines headers (car lines-chars))
197 (mail-header-set-chars headers (cadr lines-chars))
198 (gnus-cache-change-buffer group)
199 (set-buffer (cdr gnus-cache-buffer))
200 (goto-char (point-max))
202 (while (condition-case ()
204 (> (read (current-buffer)) number))
206 ;; The line was malformed, so we just remove it!!
214 (when (< (read (current-buffer)) number)
219 (nnheader-insert-nov headers)
220 ;; Update the active info.
221 (set-buffer gnus-summary-buffer)
222 (gnus-cache-possibly-update-active group (cons number number))
223 (setq gnus-newsgroup-cached
224 (gnus-add-to-sorted-list gnus-newsgroup-cached article))
225 (gnus-summary-update-secondary-mark article))
228 (defun gnus-cache-enter-remove-article (article)
229 "Mark ARTICLE for later possible removal."
231 (push article gnus-cache-removable-articles)))
233 (defun gnus-cache-possibly-remove-articles ()
234 "Possibly remove some of the removable articles."
235 (if (not (gnus-virtual-group-p gnus-newsgroup-name))
236 (gnus-cache-possibly-remove-articles-1)
237 (let ((arts gnus-cache-removable-articles)
240 (when (setq ga (nnvirtual-find-group-art
241 (gnus-group-real-name gnus-newsgroup-name) (pop arts)))
242 (let ((gnus-cache-removable-articles (list (cdr ga)))
243 (gnus-newsgroup-name (car ga)))
244 (gnus-cache-possibly-remove-articles-1)))))
245 (setq gnus-cache-removable-articles nil)))
247 (defun gnus-cache-possibly-remove-articles-1 ()
248 "Possibly remove some of the removable articles."
249 (when (gnus-cache-fully-p gnus-newsgroup-name)
250 (let ((cache-articles gnus-newsgroup-cached))
251 (gnus-cache-change-buffer gnus-newsgroup-name)
252 (dolist (article gnus-cache-removable-articles)
253 (when (memq article cache-articles)
254 ;; The article was in the cache, so we see whether we are
255 ;; supposed to remove it from the cache.
256 (gnus-cache-possibly-remove-article
257 article (memq article gnus-newsgroup-marked)
258 (memq article gnus-newsgroup-dormant)
259 (or (memq article gnus-newsgroup-unreads)
260 (memq article gnus-newsgroup-unselected))))))
261 ;; The overview file might have been modified, save it
262 ;; safe because we're only called at group exit anyway.
263 (gnus-cache-save-buffers)))
265 (defun gnus-cache-request-article (article group)
266 "Retrieve ARTICLE in GROUP from the cache."
267 (let ((file (gnus-cache-file-name group article))
268 (buffer-read-only nil)
269 (file-name-coding-system nnmail-pathname-coding-system))
270 (when (file-exists-p file)
272 (gnus-kill-all-overlays)
273 (let ((coding-system-for-read gnus-cache-coding-system))
274 (insert-file-contents file))
277 (defun gnus-cache-possibly-alter-active (group active)
278 "Alter the ACTIVE info for GROUP to reflect the articles in the cache."
279 (when gnus-cache-active-hashtb
280 (let ((cache-active (gnus-gethash group gnus-cache-active-hashtb)))
282 (when (< (car cache-active) (car active))
283 (setcar active (car cache-active)))
284 (when (> (cdr cache-active) (cdr active))
285 (setcdr active (cdr cache-active)))))))
287 (defun gnus-cache-retrieve-headers (articles group &optional fetch-old)
288 "Retrieve the headers for ARTICLES in GROUP."
290 (setq gnus-newsgroup-cached (gnus-cache-articles-in-group group))))
292 ;; No cached articles here, so we just retrieve them
294 (let ((gnus-use-cache nil))
295 (gnus-retrieve-headers articles group fetch-old))
296 (let ((uncached-articles (gnus-sorted-difference articles cached))
297 (cache-file (gnus-cache-file-name group ".overview"))
299 (file-name-coding-system nnmail-pathname-coding-system))
300 ;; We first retrieve all the headers that we don't have in
302 (let ((gnus-use-cache nil))
303 (when uncached-articles
304 (setq type (and articles
305 (gnus-retrieve-headers
306 uncached-articles group fetch-old)))))
307 (gnus-cache-save-buffers)
308 ;; Then we insert the cached headers.
311 ((not (file-exists-p cache-file))
312 ;; There are no cached headers.
315 ;; There were no uncached headers (or retrieval was
316 ;; unsuccessful), so we use the cached headers exclusively.
317 (set-buffer nntp-server-buffer)
319 (let ((coding-system-for-read
320 gnus-cache-overview-coding-system))
321 (insert-file-contents cache-file))
324 ;; We have both cached and uncached NOV headers, so we
326 (gnus-cache-braid-nov group cached)
330 (gnus-cache-braid-heads group (gnus-sorted-intersection
334 (defun gnus-cache-enter-article (&optional n)
335 "Enter the next N articles into the cache.
336 If not given a prefix, use the process marked articles instead.
337 Returns the list of articles entered."
340 (dolist (article (gnus-summary-work-articles n))
341 (gnus-summary-remove-process-mark article)
342 (if (natnump article)
343 (when (gnus-cache-possibly-enter-article
344 gnus-newsgroup-name article
346 (setq gnus-newsgroup-undownloaded (delq article gnus-newsgroup-undownloaded))
348 (gnus-message 2 "Can't cache article %d" article))
349 (gnus-summary-update-download-mark article)
350 (gnus-summary-update-secondary-mark article))
351 (gnus-summary-next-subject 1)
352 (gnus-summary-position-point)
355 (defun gnus-cache-remove-article (&optional n)
356 "Remove the next N articles from the cache.
357 If not given a prefix, use the process marked articles instead.
358 Returns the list of articles removed."
360 (gnus-cache-change-buffer gnus-newsgroup-name)
362 (dolist (article (gnus-summary-work-articles n))
363 (gnus-summary-remove-process-mark article)
364 (when (gnus-cache-possibly-remove-article article nil nil nil t)
365 (when gnus-newsgroup-agentized
366 (let ((alist (gnus-agent-load-alist gnus-newsgroup-name)))
367 (unless (cdr (assoc article alist))
368 (setq gnus-newsgroup-undownloaded
369 (gnus-add-to-sorted-list
370 gnus-newsgroup-undownloaded article)))))
372 (gnus-summary-update-download-mark article)
373 (gnus-summary-update-secondary-mark article))
374 (gnus-summary-next-subject 1)
375 (gnus-summary-position-point)
378 (defun gnus-cached-article-p (article)
379 "Say whether ARTICLE is cached in the current group."
380 (memq article gnus-newsgroup-cached))
382 (defun gnus-summary-insert-cached-articles ()
383 "Insert all the articles cached for this group into the current buffer."
385 (let ((gnus-verbose (max 6 gnus-verbose)))
386 (if (not gnus-newsgroup-cached)
387 (gnus-message 3 "No cached articles for this group")
388 (gnus-summary-goto-subjects gnus-newsgroup-cached))))
390 (defun gnus-summary-limit-include-cached ()
391 "Limit the summary buffer to articles that are cached."
393 (let ((gnus-verbose (max 6 gnus-verbose)))
394 (if gnus-newsgroup-cached
396 (gnus-summary-limit gnus-newsgroup-cached)
397 (gnus-summary-position-point))
398 (gnus-message 3 "No cached articles for this group"))))
400 ;;; Internal functions.
402 (defun gnus-cache-change-buffer (group)
403 (and gnus-cache-buffer
404 ;; See if the current group's overview cache has been loaded.
405 (or (string= group (car gnus-cache-buffer))
406 ;; Another overview cache is current, save it.
407 (gnus-cache-save-buffers)))
408 ;; if gnus-cache buffer is nil, create it
409 (unless gnus-cache-buffer
410 ;; Create cache buffer
412 (setq gnus-cache-buffer
414 (set-buffer (gnus-get-buffer-create
415 " *gnus-cache-overview*"))))
416 ;; Insert the contents of this group's cache overview.
418 (let ((file (gnus-cache-file-name group ".overview"))
419 (file-name-coding-system nnmail-pathname-coding-system))
420 (when (file-exists-p file)
421 (nnheader-insert-file-contents file)))
422 ;; We have a fresh (empty/just loaded) buffer,
423 ;; mark it as unmodified to save a redundant write later.
424 (set-buffer-modified-p nil))))
426 ;; Return whether an article is a member of a class.
427 (defun gnus-cache-member-of-class (class ticked dormant unread)
428 (or (and ticked (memq 'ticked class))
429 (and dormant (memq 'dormant class))
430 (and unread (memq 'unread class))
431 (and (not unread) (not ticked) (not dormant) (memq 'read class))))
433 (defvar gnus-cache-decoded-group-names nil
434 "Alist of original group names and decoded group names.
435 Decoding is done according to `gnus-group-name-charset-method-alist'
436 or `gnus-group-name-charset-group-alist'.")
438 (defvar gnus-cache-unified-group-names nil
439 "Alist of unified decoded group names and original group names.
440 A group name is decoded according to
441 `gnus-group-name-charset-method-alist' or
442 `gnus-group-name-charset-group-alist' first, and is encoded and
443 decoded again according to `nnmail-pathname-coding-system',
444 `file-name-coding-system', or `default-file-name-coding-system'.
446 It is used when asking for a original group name from a cache
447 directory name, in which non-ASCII characters might have been unified
448 into the ones of a certain charset particularly if the `utf-8' coding
449 system for example was used.")
451 (defun gnus-cache-decoded-group-name (group)
452 "Return a decoded group name of GROUP."
453 (or (cdr (assoc group gnus-cache-decoded-group-names))
454 (let ((decoded (gnus-group-decoded-name group))
455 (coding (or nnmail-pathname-coding-system
456 (and (boundp 'file-name-coding-system)
457 file-name-coding-system)
458 (and (boundp 'default-file-name-coding-system)
459 default-file-name-coding-system))))
460 (push (cons group decoded) gnus-cache-decoded-group-names)
461 (push (cons (mm-decode-coding-string
462 (mm-encode-coding-string decoded coding)
465 gnus-cache-unified-group-names)
468 (defun gnus-cache-file-name (group article)
469 (setq group (gnus-cache-decoded-group-name group))
471 (if (stringp article) article (int-to-string article))
472 (file-name-as-directory
474 (nnheader-translate-file-chars
475 (if (gnus-use-long-file-name 'not-cache)
477 (let ((group (nnheader-replace-duplicate-chars-in-string
478 (nnheader-replace-chars-in-string group ?/ ?_)
480 ;; Translate the first colon into a slash.
481 (when (string-match ":" group)
482 (setq group (concat (substring group 0 (match-beginning 0))
483 "/" (substring group (match-end 0)))))
484 (nnheader-replace-chars-in-string group ?. ?/)))
486 gnus-cache-directory))))
488 (defun gnus-cache-update-article (group article)
489 "If ARTICLE is in the cache, remove it and re-enter it."
490 (gnus-cache-change-buffer group)
491 (when (gnus-cache-possibly-remove-article article nil nil nil t)
492 (let ((gnus-use-cache nil))
493 (gnus-cache-possibly-enter-article
494 gnus-newsgroup-name article
497 (defun gnus-cache-possibly-remove-article (article ticked dormant unread
499 "Possibly remove ARTICLE from the cache."
500 (let ((group gnus-newsgroup-name)
503 (file-name-coding-system nnmail-pathname-coding-system))
504 ;; If this is a virtual group, we find the real group.
505 (when (gnus-virtual-group-p group)
506 (let ((result (nnvirtual-find-group-art
507 (gnus-group-real-name group) article)))
508 (setq group (car result)
509 number (cdr result))))