lisp/gnus-cache.el

   1 ;;; gnus-cache.el --- cache interface for Gnus
   2
   3 ;; Copyright (C) 1995 Free Software Foundation, Inc.
   4
   5 ;; Author: Lars Magne Ingebrigtsen <larsi@ifi.uio.no>
   6 ;; Keywords: news
   7
   8 ;; This file is part of GNU Emacs.
   9
  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)
  13 ;; any later version.
  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
  17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ;; GNU General Public License for more details.
  19
  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.
  24
  25 ;;; Commentary:
  26
  27 ;;; Code:
  28
  29 (require 'gnus)
  30
  31 (defvar gnus-cache-directory (concat gnus-article-save-directory "cache/")
  32   "*The directory where cached articles will be stored.")
  33
  34 (defvar gnus-cache-enter-articles '(ticked dormant)
  35   "*Classes of articles to enter into the cache.")
  36
  37 (defvar gnus-cache-remove-articles '(read)
  38   "*Classes of articles to remove from the cache.")
  39
  40 \f
  41
  42 (defvar gnus-cache-buffer nil)
  43
  44 \f
  45
  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
  53   (or gnus-cache-buffer
  54       ;; create cache buffer
  55       (save-excursion
  56         (setq gnus-cache-buffer
  57               (cons group
  58                     (set-buffer (get-buffer-create " *gnus-cache-overview*"))))
  59         (buffer-disable-undo (current-buffer))
  60         ;; insert the contents of this groups cache overview
  61         (erase-buffer)
  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))))
  68
  69
  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)
  74       ()
  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)
  80           (save-excursion
  81             (set-buffer buffer)
  82             (if (> (buffer-size) 0)
  83                 ;; non-empty overview, write it out
  84                 (progn
  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
  92               (condition-case nil
  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))
  97                 (error nil)))))
  98       ;; kill the buffer, it's either unmodified or saved
  99       (gnus-kill-buffer buffer)
 100       (setq gnus-cache-buffer nil))))
 101
 102
 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))))
 109
 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)
 113               group
 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))))
 119
 120 (defun gnus-cache-possibly-enter-article
 121   (group article headers ticked dormant unread)
 122   (let ((number (mail-header-number headers))
 123         file dir)
 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))))
 129         ()                              ; Do nothing.
 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))
 138         (save-excursion
 139           (set-buffer gnus-article-buffer)
 140           (save-restriction
 141             (widen)
 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))
 146           (forward-line -1)
 147           (while (condition-case ()
 148                      (and (not (bobp))
 149                           (> (read (current-buffer)) number))
 150                    (error
 151                     ;; The line was malformed, so we just remove it!!
 152                     (gnus-delete-line)
 153                     t))
 154             (forward-line -1))
 155           (if (bobp)
 156               (if (not (eobp))
 157                   (progn
 158                     (beginning-of-line)
 159                     (if (< (read (current-buffer)) number)
 160                         (forward-line 1)))
 161                 (beginning-of-line))
 162             (forward-line 1))
 163           (beginning-of-line)
 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) ""))))
 175         t))))
 176
 177 (defun gnus-cache-enter-remove-article (article)
 178   (setq gnus-cache-removable-articles
 179         (cons article gnus-cache-removable-articles)))
 180
 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)))
 187         nil
 188       (save-excursion
 189         (delete-file file)
 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")
 194                                 (point-max) t))
 195             (delete-region (progn (beginning-of-line) (point))
 196                            (progn (forward-line 1) (point))))))))
 197
 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))
 201         article)
 202     (gnus-cache-change-buffer gnus-newsgroup-name)
 203     (while articles
 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))
 217
 218
 219 (defun gnus-cache-request-article (article group)
 220   (let ((file (gnus-cache-file-name group article)))
 221     (if (not (file-exists-p file))
 222         ()
 223       (erase-buffer)
 224       ;; There may be some overlays that we have to kill...
 225       (insert "i")
 226       (let ((overlays (overlays-at (point-min))))
 227         (while overlays
 228           (delete-overlay (car overlays))
 229           (setq overlays (cdr overlays))))
 230       (erase-buffer)
 231       (insert-file-contents file)
 232       t)))
 233
 234 (defun gnus-cache-articles-in-group (group)
 235   (let ((dir (file-name-directory (gnus-cache-file-name group 1)))
 236         articles)
 237     (if (not (file-exists-p dir))
 238         nil
 239       (setq articles (directory-files dir nil "^[0-9]+$" t))
 240       (if (not articles)
 241           nil
 242         (sort (mapcar (function (lambda (name)
 243                                   (string-to-int name)))
 244                       articles)
 245               '<)))))
 246
 247 (defun gnus-cache-active-articles (group)
 248   (let ((articles (gnus-cache-articles-in-group group)))
 249     (and articles
 250          (cons (car articles) (gnus-last-element articles)))))
 251
 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)))))
 258
 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"))
 263          type)
 264     (let ((gnus-use-cache nil))
 265       (setq type (and articles (gnus-retrieve-headers articles group))))
 266     (gnus-cache-save-buffers)
 267     (save-excursion
 268       (cond ((not (file-exists-p cache-file))
 269              type)
 270             ((null type)
 271              (set-buffer nntp-server-buffer)
 272              (erase-buffer)
 273              (insert-file-contents cache-file)
 274              'nov)
 275             ((eq type 'nov)
 276              (gnus-cache-braid-nov group cached)
 277              type)
 278             (t
 279              (gnus-cache-braid-heads group cached)
 280              type)))))
 281
 282 (defun gnus-cache-braid-nov (group cached)
 283   (let ((cache-buf (get-buffer-create " *gnus-cache*"))
 284         beg end)
 285     (gnus-cache-save-buffers)
 286     (save-excursion
 287       (set-buffer cache-buf)
 288       (buffer-disable-undo (current-buffer))
 289       (erase-buffer)
 290       (insert-file-contents (gnus-cache-file-name group ".overview"))
 291       (goto-char (point-min))
 292       (insert "\n")
 293       (goto-char (point-min)))
 294     (set-buffer nntp-server-buffer)
 295     (goto-char (point-min))
 296     (while cached
 297       (while (and (not (eobp))
 298                   (< (read (current-buffer)) (car cached)))
 299         (forward-line 1))
 300       (beginning-of-line)
 301       (save-excursion
 302         (set-buffer cache-buf)
 303         (if (search-forward (concat "\n" (int-to-string (car cached)) "\t")
 304                             nil t)
 305             (setq beg (progn (beginning-of-line) (point))
 306                   end (progn (end-of-line) (point)))
 307           (setq beg nil)))
 308       (if beg (progn (insert-buffer-substring cache-buf beg end)
 309                      (insert "\n")))
 310       (setq cached (cdr cached)))
 311     (kill-buffer cache-buf)))
 312
 313 (defun gnus-cache-braid-heads (group cached)
 314   (let ((cache-buf (get-buffer-create " *gnus-cache*")))
 315     (save-excursion
 316       (set-buffer cache-buf)
 317       (buffer-disable-undo (current-buffer))
 318       (erase-buffer))
 319     (set-buffer nntp-server-buffer)
 320     (goto-char (point-min))
 321     (while cached
 322       (while (and (not (eobp))
 323                   (looking-at "2.. +\\([0-9]+\\) ")
 324                   (< (progn (goto-char (match-beginning 1))
 325                             (read (current-buffer)))
 326                      (car cached)))
 327         (search-forward "\n.\n" nil 'move))
 328       (beginning-of-line)
 329       (save-excursion
 330         (set-buffer cache-buf)
 331         (erase-buffer)
 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))
 337         (forward-char -1)
 338         (insert "."))
 339       (insert-buffer-substring cache-buf)
 340       (setq cached (cdr cached)))
 341     (kill-buffer cache-buf)))
 342
 343 (defun gnus-jog-cache ()
 344   "Go through all groups and put the articles into the cache."
 345   (interactive)
 346   (let ((newsrc (cdr gnus-newsrc-alist))
 347         (gnus-cache-enter-articles '(unread))
 348         (gnus-mark-article-hook nil)
 349         (gnus-expert-user t)
 350         (gnus-large-newsgroup nil))
 351     (while newsrc
 352       (gnus-summary-read-group (car (car newsrc)))
 353       (if (not (eq major-mode 'gnus-summary-mode))
 354           ()
 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)))))
 360
 361 (provide 'gnus-cache)
 362
 363 ;;; gnus-cache.el ends here