+(defun gnus-cache-possibly-enter-article
+ (group article headers ticked dormant unread &optional force)
+ (when (and (or force (not (eq gnus-use-cache 'passive)))
+ (numberp article)
+ (> article 0)
+ (vectorp headers)) ; This might be a dummy article.
+ ;; If this is a virtual group, we find the real group.
+ (when (gnus-virtual-group-p group)
+ (let ((result (nnvirtual-find-group-art
+ (gnus-group-real-name group) article)))
+ (setq group (car result)
+ headers (copy-sequence headers))
+ (mail-header-set-number headers (cdr result))))
+ (let ((number (mail-header-number headers))
+ file dir)
+ (when (and (> number 0) ; Reffed article.
+ (or (not gnus-uncacheable-groups)
+ (not (string-match gnus-uncacheable-groups group)))
+ (or force
+ (gnus-cache-member-of-class
+ gnus-cache-enter-articles ticked dormant unread))
+ (not (file-exists-p (setq file (gnus-cache-file-name
+ group number)))))
+ ;; Possibly create the cache directory.
+ (or (file-exists-p (setq dir (file-name-directory file)))
+ (gnus-make-directory dir))
+ ;; Save the article in the cache.
+ (if (file-exists-p file)
+ t ; The article already is saved.
+ (save-excursion
+ (set-buffer nntp-server-buffer)
+ (let ((gnus-use-cache nil))
+ (gnus-request-article-this-buffer number group))
+ (when (> (buffer-size) 0)
+ (write-region (point-min) (point-max) file nil 'quiet)
+ (gnus-cache-change-buffer group)
+ (set-buffer (cdr gnus-cache-buffer))
+ (goto-char (point-max))
+ (forward-line -1)
+ (while (condition-case ()
+ (and (not (bobp))
+ (> (read (current-buffer)) number))
+ (error
+ ;; The line was malformed, so we just remove it!!
+ (gnus-delete-line)
+ t))
+ (forward-line -1))
+ (if (bobp)
+ (if (not (eobp))
+ (progn
+ (beginning-of-line)
+ (if (< (read (current-buffer)) number)
+ (forward-line 1)))
+ (beginning-of-line))
+ (forward-line 1))
+ (beginning-of-line)
+ ;; [number subject from date id references chars lines xref]
+ (insert (format "%s\t%s\t%s\t%s\t%s\t%s\t%s\t%s\t%s\t\n"
+ (mail-header-number headers)
+ (mail-header-subject headers)
+ (mail-header-from headers)
+ (mail-header-date headers)
+ (mail-header-id headers)
+ (or (mail-header-references headers) "")
+ (or (mail-header-chars headers) "")
+ (or (mail-header-lines headers) "")
+ (or (mail-header-xref headers) "")))
+ ;; Update the active info.
+ (set-buffer gnus-summary-buffer)
+ (gnus-cache-update-active group number)
+ (push article gnus-newsgroup-cached)
+ (gnus-summary-update-secondary-mark article))
+ t))))))
+
+(defun gnus-cache-enter-remove-article (article)
+ "Mark ARTICLE for later possible removal."
+ (when article
+ (push article gnus-cache-removable-articles)))
+
+(defun gnus-cache-possibly-remove-articles ()
+ "Possibly remove some of the removable articles."
+ (if (not (gnus-virtual-group-p gnus-newsgroup-name))
+ (gnus-cache-possibly-remove-articles-1)
+ (let ((arts gnus-cache-removable-articles)
+ ga)
+ (while arts
+ (when (setq ga (nnvirtual-find-group-art
+ (gnus-group-real-name gnus-newsgroup-name) (pop arts)))
+ (let ((gnus-cache-removable-articles (list (cdr ga)))
+ (gnus-newsgroup-name (car ga)))
+ (gnus-cache-possibly-remove-articles-1)))))
+ (setq gnus-cache-removable-articles nil)))
+
+(defun gnus-cache-possibly-remove-articles-1 ()
+ "Possibly remove some of the removable articles."
+ (unless (eq gnus-use-cache 'passive)
+ (let ((articles gnus-cache-removable-articles)
+ (cache-articles gnus-newsgroup-cached)
+ article)
+ (gnus-cache-change-buffer gnus-newsgroup-name)
+ (while articles
+ (if (memq (setq article (pop articles)) cache-articles)
+ ;; The article was in the cache, so we see whether we are
+ ;; supposed to remove it from the cache.
+ (gnus-cache-possibly-remove-article
+ article (memq article gnus-newsgroup-marked)
+ (memq article gnus-newsgroup-dormant)
+ (or (memq article gnus-newsgroup-unreads)
+ (memq article gnus-newsgroup-unselected))))))
+ ;; The overview file might have been modified, save it
+ ;; safe because we're only called at group exit anyway.
+ (gnus-cache-save-buffers)))
+
+(defun gnus-cache-request-article (article group)
+ "Retrieve ARTICLE in GROUP from the cache."
+ (let ((file (gnus-cache-file-name group article))
+ (buffer-read-only nil))
+ (when (file-exists-p file)
+ (erase-buffer)
+ (gnus-kill-all-overlays)
+ (insert-file-contents file)
+ t)))
+
+(defun gnus-cache-possibly-alter-active (group active)
+ "Alter the ACTIVE info for GROUP to reflect the articles in the cache."
+ (let ((cache-active (gnus-gethash group gnus-cache-active-hashtb)))
+ (and cache-active
+ (< (car cache-active) (car active))
+ (setcar active (car cache-active)))
+ (and cache-active
+ (> (cdr cache-active) (cdr active))
+ (setcdr active (cdr cache-active)))))
+
+(defun gnus-cache-retrieve-headers (articles group &optional fetch-old)
+ "Retrieve the headers for ARTICLES in GROUP."
+ (let ((cached
+ (setq gnus-newsgroup-cached (gnus-cache-articles-in-group group))))
+ (if (not cached)
+ ;; No cached articles here, so we just retrieve them
+ ;; the normal way.
+ (let ((gnus-use-cache nil))
+ (gnus-retrieve-headers articles group fetch-old))
+ (let ((uncached-articles (gnus-sorted-intersection
+ (gnus-sorted-complement articles cached)
+ articles))
+ (cache-file (gnus-cache-file-name group ".overview"))
+ type)
+ ;; We first retrieve all the headers that we don't have in
+ ;; the cache.
+ (let ((gnus-use-cache nil))
+ (when uncached-articles
+ (setq type (and articles
+ (gnus-retrieve-headers
+ uncached-articles group fetch-old)))))
+ (gnus-cache-save-buffers)
+ ;; Then we insert the cached headers.
+ (save-excursion
+ (cond
+ ((not (file-exists-p cache-file))
+ ;; There are no cached headers.
+ type)
+ ((null type)
+ ;; There were no uncached headers (or retrieval was
+ ;; unsuccessful), so we use the cached headers exclusively.
+ (set-buffer nntp-server-buffer)
+ (erase-buffer)
+ (insert-file-contents cache-file)
+ 'nov)
+ ((eq type 'nov)
+ ;; We have both cached and uncached NOV headers, so we
+ ;; braid them.
+ (gnus-cache-braid-nov group cached)
+ type)
+ (t
+ ;; We braid HEADs.
+ (gnus-cache-braid-heads group (gnus-sorted-intersection
+ cached articles))
+ type)))))))
+
+(defun gnus-cache-enter-article (&optional n)
+ "Enter the next N articles into the cache.
+If not given a prefix, use the process marked articles instead.
+Returns the list of articles entered."
+ (interactive "P")
+ (gnus-set-global-variables)
+ (let ((articles (gnus-summary-work-articles n))
+ article out)
+ (while articles
+ (setq article (pop articles))
+ (when (gnus-cache-possibly-enter-article
+ gnus-newsgroup-name article (gnus-summary-article-header article)
+ nil nil nil t)
+ (push article out))
+ (gnus-summary-remove-process-mark article)
+ (gnus-summary-update-secondary-mark article))
+ (gnus-summary-next-subject 1)
+ (gnus-summary-position-point)
+ (nreverse out)))
+
+(defun gnus-cache-remove-article (n)
+ "Remove the next N articles from the cache.
+If not given a prefix, use the process marked articles instead.
+Returns the list of articles removed."
+ (interactive "P")
+ (gnus-set-global-variables)
+ (gnus-cache-change-buffer gnus-newsgroup-name)
+ (let ((articles (gnus-summary-work-articles n))
+ article out)
+ (while articles
+ (setq article (pop articles))
+ (when (gnus-cache-possibly-remove-article article nil nil nil t)
+ (push article out))
+ (gnus-summary-remove-process-mark article)
+ (gnus-summary-update-secondary-mark article))
+ (gnus-summary-next-subject 1)
+ (gnus-summary-position-point)
+ (nreverse out)))
+
+(defun gnus-cached-article-p (article)
+ "Say whether ARTICLE is cached in the current group."
+ (memq article gnus-newsgroup-cached))
+
+;;; Internal functions.
+
+(defun gnus-cache-change-buffer (group)
+ (and gnus-cache-buffer
+ ;; See if the current group's overview cache has been loaded.
+ (or (string= group (car gnus-cache-buffer))
+ ;; Another overview cache is current, save it.
+ (gnus-cache-save-buffers)))
+ ;; if gnus-cache buffer is nil, create it
+ (or gnus-cache-buffer
+ ;; Create cache buffer
+ (save-excursion
+ (setq gnus-cache-buffer
+ (cons group
+ (set-buffer (get-buffer-create " *gnus-cache-overview*"))))
+ (buffer-disable-undo (current-buffer))
+ ;; Insert the contents of this group's cache overview.
+ (erase-buffer)
+ (let ((file (gnus-cache-file-name group ".overview")))
+ (and (file-exists-p file)
+ (insert-file-contents file)))
+ ;; We have a fresh (empty/just loaded) buffer,
+ ;; mark it as unmodified to save a redundant write later.
+ (set-buffer-modified-p nil))))