lisp/gnus/gnus-cache.el

   1 ;;; gnus-cache.el --- cache interface for Gnus
   2 ;; Copyright (C) 1995, 1996, 1997, 1998, 1999, 2000
   3 ;;        Free Software Foundation, Inc.
   4
   5 ;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
   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 (eval-when-compile (require 'cl))
  30
  31 (require 'gnus)
  32 (require 'gnus-int)
  33 (require 'gnus-range)
  34 (require 'gnus-start)
  35 (eval-when-compile
  36   (require 'gnus-sum))
  37
  38 (defcustom gnus-cache-active-file
  39   (expand-file-name "active" gnus-cache-directory)
  40   "*The cache active file."
  41   :group 'gnus-cache
  42   :type 'file)
  43
  44 (defcustom gnus-cache-enter-articles '(ticked dormant)
  45   "Classes of articles to enter into the cache."
  46   :group 'gnus-cache
  47   :type '(set (const ticked) (const dormant) (const unread) (const read)))
  48
  49 (defcustom gnus-cache-remove-articles '(read)
  50   "Classes of articles to remove from the cache."
  51   :group 'gnus-cache
  52   :type '(set (const ticked) (const dormant) (const unread) (const read)))
  53
  54 (defcustom gnus-cacheable-groups nil
  55   "*Groups that match this regexp will be cached.
  56
  57 If you only want to cache your nntp groups, you could set this
  58 variable to \"^nntp\".
  59
  60 If a group matches both gnus-cacheable-groups and gnus-uncacheable-groups
  61 it's not cached."
  62   :group 'gnus-cache
  63   :type '(choice (const :tag "off" nil)
  64                  regexp))
  65
  66 (defcustom gnus-uncacheable-groups nil
  67   "*Groups that match this regexp will not be cached.
  68
  69 If you want to avoid caching your nnml groups, you could set this
  70 variable to \"^nnml\".
  71
  72 If a group matches both gnus-cacheable-groups and gnus-uncacheable-groups
  73 it's not cached."
  74   :group 'gnus-cache
  75   :type '(choice (const :tag "off" nil)
  76                  regexp))
  77
  78 (defvar gnus-cache-overview-coding-system 'raw-text
  79   "Coding system used on Gnus cache files.")
  80
  81 (defvar gnus-cache-coding-system 'raw-text
  82   "Coding system used on Gnus cache files.")
  83
  84 \f
  85
  86 ;;; Internal variables.
  87
  88 (defvar gnus-cache-removable-articles nil)
  89 (defvar gnus-cache-buffer nil)
  90 (defvar gnus-cache-active-hashtb nil)
  91 (defvar gnus-cache-active-altered nil)
  92
  93 (eval-and-compile
  94   (autoload 'nnml-generate-nov-databases-1 "nnml")
  95   (autoload 'nnvirtual-find-group-art "nnvirtual"))
  96
  97 \f
  98
  99 ;;; Functions called from Gnus.
 100
 101 (defun gnus-cache-open ()
 102   "Initialize the cache."
 103   (when (or (file-exists-p gnus-cache-directory)
 104             (and gnus-use-cache
 105                  (not (eq gnus-use-cache 'passive))))
 106     (gnus-cache-read-active)))
 107
 108 ;; Complexities of byte-compiling make this kludge necessary.  Eeek.
 109 (ignore-errors
 110   (gnus-add-shutdown 'gnus-cache-close 'gnus))
 111
 112 (defun gnus-cache-close ()
 113   "Shut down the cache."
 114   (gnus-cache-write-active)
 115   (gnus-cache-save-buffers)
 116   (setq gnus-cache-active-hashtb nil))
 117
 118 (defun gnus-cache-save-buffers ()
 119   ;; save the overview buffer if it exists and has been modified
 120   ;; delete empty cache subdirectories
 121   (when gnus-cache-buffer
 122     (let ((buffer (cdr gnus-cache-buffer))
 123           (overview-file (gnus-cache-file-name
 124                           (car gnus-cache-buffer) ".overview")))
 125       ;; write the overview only if it was modified
 126       (when (buffer-modified-p buffer)
 127         (save-excursion
 128           (set-buffer buffer)
 129           (if (> (buffer-size) 0)
 130               ;; Non-empty overview, write it to a file.
 131               (let ((coding-system-for-write
 132                      gnus-cache-overview-coding-system))
 133                 (gnus-write-buffer overview-file))
 134             ;; Empty overview file, remove it
 135             (when (file-exists-p overview-file)
 136               (delete-file overview-file))
 137             ;; If possible, remove group's cache subdirectory.
 138             (condition-case nil
 139                 ;; FIXME: we can detect the error type and warn the user
 140                 ;; of any inconsistencies (articles w/o nov entries?).
 141                 ;; for now, just be conservative...delete only if safe -- sj
 142                 (delete-directory (file-name-directory overview-file))
 143               (error nil)))))
 144       ;; Kill the buffer -- it's either unmodified or saved.
 145       (gnus-kill-buffer buffer)
 146       (setq gnus-cache-buffer nil))))
 147
 148 (defun gnus-cache-possibly-enter-article
 149   (group article ticked dormant unread &optional force)
 150   (when (and (or force (not (eq gnus-use-cache 'passive)))
 151              (numberp article)
 152              (> article 0))             ; This might be a dummy article.
 153     (let ((number article) file headers)
 154       ;; If this is a virtual group, we find the real group.
 155       (when (gnus-virtual-group-p group)
 156         (let ((result (nnvirtual-find-group-art
 157                        (gnus-group-real-name group) article)))
 158           (setq group (car result)
 159                 number (cdr result))))
 160       (when (and number
 161                  (> number 0)           ; Reffed article.
 162                  (or force
 163                      (and (or (not gnus-cacheable-groups)
 164                               (string-match gnus-cacheable-groups group))
 165                           (or (not gnus-uncacheable-groups)
 166                               (not (string-match
 167                                     gnus-uncacheable-groups group)))
 168                           (gnus-cache-member-of-class
 169                            gnus-cache-enter-articles ticked dormant unread)))
 170                  (not (file-exists-p (setq file (gnus-cache-file-name
 171                                                  group number)))))
 172         ;; Possibly create the cache directory.
 173         (gnus-make-directory (file-name-directory file))
 174         ;; Save the article in the cache.
 175         (if (file-exists-p file)
 176             t                           ; The article already is saved.
 177           (save-excursion
 178             (set-buffer nntp-server-buffer)
 179             (require 'gnus-art)
 180             (let ((gnus-use-cache nil)
 181                   (gnus-article-decode-hook nil))
 182               (gnus-request-article-this-buffer number group))
 183             (when (> (buffer-size) 0)
 184               (let ((coding-system-for-write gnus-cache-coding-system))
 185                 (gnus-write-buffer file))
 186               (setq headers (nnheader-parse-head t))
 187               (mail-header-set-number headers number)
 188               (gnus-cache-change-buffer group)
 189               (set-buffer (cdr gnus-cache-buffer))
 190               (goto-char (point-max))
 191               (forward-line -1)
 192               (while (condition-case ()
 193                          (when (not (bobp))
 194                            (> (read (current-buffer)) number))
 195                        (error
 196                         ;; The line was malformed, so we just remove it!!
 197                         (gnus-delete-line)
 198                         t))
 199                 (forward-line -1))
 200               (if (bobp)
 201                   (if (not (eobp))
 202                       (progn
 203                         (beginning-of-line)
 204                         (when (< (read (current-buffer)) number)
 205                           (forward-line 1)))
 206                     (beginning-of-line))
 207                 (forward-line 1))
 208               (beginning-of-line)
 209               (nnheader-insert-nov headers)
 210               ;; Update the active info.
 211               (set-buffer gnus-summary-buffer)
 212               (gnus-cache-update-active group number)
 213               (push article gnus-newsgroup-cached)
 214               (gnus-summary-update-secondary-mark article))
 215             t))))))
 216
 217 (defun gnus-cache-enter-remove-article (article)
 218   "Mark ARTICLE for later possible removal."
 219   (when article
 220     (push article gnus-cache-removable-articles)))
 221
 222 (defun gnus-cache-possibly-remove-articles ()
 223   "Possibly remove some of the removable articles."
 224   (if (not (gnus-virtual-group-p gnus-newsgroup-name))
 225       (gnus-cache-possibly-remove-articles-1)
 226     (let ((arts gnus-cache-removable-articles)
 227           ga)
 228       (while arts
 229         (when (setq ga (nnvirtual-find-group-art
 230                         (gnus-group-real-name gnus-newsgroup-name) (pop arts)))
 231           (let ((gnus-cache-removable-articles (list (cdr ga)))
 232                 (gnus-newsgroup-name (car ga)))
 233             (gnus-cache-possibly-remove-articles-1)))))
 234     (setq gnus-cache-removable-articles nil)))
 235
 236 (defun gnus-cache-possibly-remove-articles-1 ()
 237   "Possibly remove some of the removable articles."
 238   (unless (eq gnus-use-cache 'passive)
 239     (let ((articles gnus-cache-removable-articles)
 240           (cache-articles gnus-newsgroup-cached)
 241           article)
 242       (gnus-cache-change-buffer gnus-newsgroup-name)
 243       (while articles
 244         (when (memq (setq article (pop articles)) cache-articles)
 245           ;; The article was in the cache, so we see whether we are
 246           ;; supposed to remove it from the cache.
 247           (gnus-cache-possibly-remove-article
 248            article (memq article gnus-newsgroup-marked)
 249            (memq article gnus-newsgroup-dormant)
 250            (or (memq article gnus-newsgroup-unreads)
 251                (memq article gnus-newsgroup-unselected))))))
 252     ;; The overview file might have been modified, save it
 253     ;; safe because we're only called at group exit anyway.
 254     (gnus-cache-save-buffers)))
 255
 256 (defun gnus-cache-request-article (article group)
 257   "Retrieve ARTICLE in GROUP from the cache."
 258   (let ((file (gnus-cache-file-name group article))
 259         (buffer-read-only nil))
 260     (when (file-exists-p file)
 261       (erase-buffer)
 262       (gnus-kill-all-overlays)
 263       (let ((coding-system-for-read gnus-cache-coding-system))
 264         (insert-file-contents file))
 265       t)))
 266
 267 (defun gnus-cache-possibly-alter-active (group active)
 268   "Alter the ACTIVE info for GROUP to reflect the articles in the cache."
 269   (when gnus-cache-active-hashtb
 270     (let ((cache-active (gnus-gethash group gnus-cache-active-hashtb)))
 271       (when cache-active
 272         (when (< (car cache-active) (car active))
 273           (setcar active (car cache-active)))
 274         (when (> (cdr cache-active) (cdr active))
 275           (setcdr active (cdr cache-active)))))))
 276
 277 (defun gnus-cache-retrieve-headers (articles group &optional fetch-old)
 278   "Retrieve the headers for ARTICLES in GROUP."
 279   (let ((cached
 280          (setq gnus-newsgroup-cached (gnus-cache-articles-in-group group))))
 281     (if (not cached)
 282         ;; No cached articles here, so we just retrieve them
 283         ;; the normal way.
 284         (let ((gnus-use-cache nil))
 285           (gnus-retrieve-headers articles group fetch-old))
 286       (let ((uncached-articles (gnus-sorted-intersection
 287                                 (gnus-sorted-complement articles cached)
 288                                 articles))
 289             (cache-file (gnus-cache-file-name group ".overview"))
 290             type)
 291         ;; We first retrieve all the headers that we don't have in
 292         ;; the cache.
 293         (let ((gnus-use-cache nil))
 294           (when uncached-articles
 295             (setq type (and articles
 296                             (gnus-retrieve-headers
 297                              uncached-articles group fetch-old)))))
 298         (gnus-cache-save-buffers)
 299         ;; Then we insert the cached headers.
 300         (save-excursion
 301           (cond
 302            ((not (file-exists-p cache-file))
 303             ;; There are no cached headers.
 304             type)
 305            ((null type)
 306             ;; There were no uncached headers (or retrieval was
 307             ;; unsuccessful), so we use the cached headers exclusively.
 308             (set-buffer nntp-server-buffer)
 309             (erase-buffer)
 310             (let ((coding-system-for-read
 311                    gnus-cache-overview-coding-system))
 312               (insert-file-contents cache-file))
 313             'nov)
 314            ((eq type 'nov)
 315             ;; We have both cached and uncached NOV headers, so we
 316             ;; braid them.
 317             (gnus-cache-braid-nov group cached)
 318             type)
 319            (t
 320             ;; We braid HEADs.
 321             (gnus-cache-braid-heads group (gnus-sorted-intersection
 322                                            cached articles))
 323             type)))))))
 324
 325 (defun gnus-cache-enter-article (&optional n)
 326   "Enter the next N articles into the cache.
 327 If not given a prefix, use the process marked articles instead.
 328 Returns the list of articles entered."
 329   (interactive "P")
 330   (let ((articles (gnus-summary-work-articles n))
 331         article out)
 332     (while (setq article (pop articles))
 333       (gnus-summary-remove-process-mark article)
 334       (if (natnump article)
 335           (when (gnus-cache-possibly-enter-article
 336                  gnus-newsgroup-name article
 337                  nil nil nil t)
 338             (push article out))
 339         (gnus-message 2 "Can't cache article %d" article))
 340       (gnus-summary-update-secondary-mark article))
 341     (gnus-summary-next-subject 1)
 342     (gnus-summary-position-point)
 343     (nreverse out)))
 344
 345 (defun gnus-cache-remove-article (n)
 346   "Remove the next N articles from the cache.
 347 If not given a prefix, use the process marked articles instead.
 348 Returns the list of articles removed."
 349   (interactive "P")
 350   (gnus-cache-change-buffer gnus-newsgroup-name)
 351   (let ((articles (gnus-summary-work-articles n))
 352         article out)
 353     (while articles
 354       (setq article (pop articles))
 355       (gnus-summary-remove-process-mark article)
 356       (when (gnus-cache-possibly-remove-article article nil nil nil t)
 357         (push article out))
 358       (gnus-summary-update-secondary-mark article))
 359     (gnus-summary-next-subject 1)
 360     (gnus-summary-position-point)
 361     (nreverse out)))
 362
 363 (defun gnus-cached-article-p (article)
 364   "Say whether ARTICLE is cached in the current group."
 365   (memq article gnus-newsgroup-cached))
 366
 367 (defun gnus-summary-insert-cached-articles ()
 368   "Insert all the articles cached for this group into the current buffer."
 369   (interactive)
 370   (let ((cached (sort (copy-sequence gnus-newsgroup-cached) '>))
 371         (gnus-verbose (max 6 gnus-verbose)))
 372     (unless cached
 373       (gnus-message 3 "No cached articles for this group"))
 374     (while cached
 375       (gnus-summary-goto-subject (pop cached) t))))
 376
 377 (defalias 'gnus-summary-limit-include-cached
 378   'gnus-summary-insert-cached-articles)
 379
 380 ;;; Internal functions.
 381
 382 (defun gnus-cache-change-buffer (group)
 383   (and gnus-cache-buffer
 384        ;; See if the current group's overview cache has been loaded.
 385        (or (string= group (car gnus-cache-buffer))
 386            ;; Another overview cache is current, save it.
 387            (gnus-cache-save-buffers)))
 388   ;; if gnus-cache buffer is nil, create it
 389   (unless gnus-cache-buffer
 390     ;; Create cache buffer
 391     (save-excursion
 392       (setq gnus-cache-buffer
 393             (cons group
 394                   (set-buffer (gnus-get-buffer-create
 395                                " *gnus-cache-overview*"))))
 396       ;; Insert the contents of this group's cache overview.
 397       (erase-buffer)
 398       (let ((file (gnus-cache-file-name group ".overview")))
 399         (when (file-exists-p file)
 400           (nnheader-insert-file-contents file)))
 401       ;; We have a fresh (empty/just loaded) buffer,
 402       ;; mark it as unmodified to save a redundant write later.
 403       (set-buffer-modified-p nil))))
 404
 405 ;; Return whether an article is a member of a class.
 406 (defun gnus-cache-member-of-class (class ticked dormant unread)
 407   (or (and ticked (memq 'ticked class))
 408       (and dormant (memq 'dormant class))
 409       (and unread (memq 'unread class))
 410       (and (not unread) (not ticked) (not dormant) (memq 'read class))))
 411
 412 (defun gnus-cache-file-name (group article)
 413   (expand-file-name
 414    (if (stringp article) article (int-to-string article))
 415    (file-name-as-directory
 416     (expand-file-name
 417      (nnheader-translate-file-chars
 418       (if (gnus-use-long-file-name 'not-cache)
 419           group
 420         (let ((group (nnheader-replace-duplicate-chars-in-string
 421                       (nnheader-replace-chars-in-string group ?/ ?_)
 422                       ?. ?_)))
 423           ;; Translate the first colon into a slash.
 424           (when (string-match ":" group)
 425             (aset group (match-beginning 0) ?/))
 426           (nnheader-replace-chars-in-string group ?. ?/)))
 427       t)
 428      gnus-cache-directory))))
 429
 430 (defun gnus-cache-update-article (group article)
 431   "If ARTICLE is in the cache, remove it and re-enter it."
 432   (gnus-cache-change-buffer group)
 433   (when (gnus-cache-possibly-remove-article article nil nil nil t)
 434     (let ((gnus-use-cache nil))
 435       (gnus-cache-possibly-enter-article
 436        gnus-newsgroup-name article
 437        nil nil nil t))))
 438
 439 (defun gnus-cache-possibly-remove-article (article ticked dormant unread
 440                                                    &optional force)
 441   "Possibly remove ARTICLE from the cache."
 442   (let ((group gnus-newsgroup-name)
 443         (number article)
 444         file)
 445     ;; If this is a virtual group, we find the real group.
 446     (when (gnus-virtual-group-p group)
 447       (let ((result (nnvirtual-find-group-art
 448                      (gnus-group-real-name group) article)))
 449         (setq group (car result)
 450               number (cdr result))))
 451     (setq file (gnus-cache-file-name group number))
 452     (when (and (file-exists-p file)
 453                (or force
 454                    (gnus-cache-member-of-class
 455                     gnus-cache-remove-articles ticked dormant unread)))
 456       (save-excursion
 457         (delete-file file)
 458         (set-buffer (cdr gnus-cache-buffer))
 459         (goto-char (point-min))
 460         (when (or (looking-at (concat (int-to-string number) "\t"))
 461                   (search-forward (concat "\n" (int-to-string number) "\t")
 462                                   (point-max) t))
 463           (delete-region (progn (beginning-of-line) (point))
 464                          (progn (forward-line 1) (point)))))
 465       (setq gnus-newsgroup-cached
 466             (delq article gnus-newsgroup-cached))
 467       (gnus-summary-update-secondary-mark article)
 468       t)))
 469
 470 (defun gnus-cache-articles-in-group (group)
 471   "Return a sorted list of cached articles in GROUP."
 472   (let ((dir (file-name-directory (gnus-cache-file-name group 1)))
 473         articles)
 474     (when (file-exists-p dir)
 475       (setq articles
 476             (sort (mapcar (lambda (name) (string-to-int name))
 477                           (directory-files dir nil "^[0-9]+$" t))
 478                   '<))
 479       ;; Update the cache active file, just to synch more.
 480       (when articles
 481         (gnus-cache-update-active group (car articles) t)
 482         (gnus-cache-update-active group (car (last articles))))
 483       articles)))
 484
 485 (defun gnus-cache-braid-nov (group cached &optional file)
 486   (let ((cache-buf (gnus-get-buffer-create " *gnus-cache*"))
 487         beg end)
 488     (gnus-cache-save-buffers)
 489     (save-excursion
 490       (set-buffer cache-buf)
 491       (erase-buffer)
 492       (let ((coding-system-for-read
 493              gnus-cache-overview-coding-system))
 494         (insert-file-contents
 495          (or file (gnus-cache-file-name group ".overview"))))
 496       (goto-char (point-min))
 497       (insert "\n")
 498       (goto-char (point-min)))
 499     (set-buffer nntp-server-buffer)
 500     (goto-char (point-min))
 501     (while cached
 502       (while (and (not (eobp))
 503                   (< (read (current-buffer)) (car cached)))
 504         (forward-line 1))
 505       (beginning-of-line)
 506       (save-excursion
 507         (set-buffer cache-buf)
 508         (if (search-forward (concat "\n" (int-to-string (car cached)) "\t")
 509                             nil t)
 510             (setq beg (progn (beginning-of-line) (point))
 511                   end (progn (end-of-line) (point)))
 512           (setq beg nil)))
 513       (when beg
 514         (insert-buffer-substring cache-buf beg end)
 515         (insert "\n"))
 516       (setq cached (cdr cached)))
 517     (kill-buffer cache-buf)))
 518
 519 (defun gnus-cache-braid-heads (group cached)
 520   (let ((cache-buf (gnus-get-buffer-create " *gnus-cache*")))
 521     (save-excursion
 522       (set-buffer cache-buf)
 523       (erase-buffer))
 524     (set-buffer nntp-server-buffer)
 525     (goto-char (point-min))
 526     (while cached
 527       (while (and (not (eobp))
 528                   (looking-at "2.. +\\([0-9]+\\) ")
 529                   (< (progn (goto-char (match-beginning 1))
 530                             (read (current-buffer)))
 531                      (car cached)))
 532         (search-forward "\n.\n" nil 'move))
 533       (beginning-of-line)
 534       (save-excursion
 535         (set-buffer cache-buf)
 536         (erase-buffer)
 537         (let ((coding-system-for-read
 538                gnus-cache-coding-system))
 539           (insert-file-contents (gnus-cache-file-name group (car cached))))
 540         (goto-char (point-min))
 541         (insert "220 ")
 542         (princ (car cached) (current-buffer))
 543         (insert " Article retrieved.\n")
 544         (search-forward "\n\n" nil 'move)
 545         (delete-region (point) (point-max))
 546         (forward-char -1)
 547         (insert "."))
 548       (insert-buffer-substring cache-buf)
 549       (setq cached (cdr cached)))
 550     (kill-buffer cache-buf)))
 551
 552 ;;;###autoload
 553 (defun gnus-jog-cache ()
 554   "Go through all groups and put the articles into the cache.
 555
 556 Usage:
 557 $ emacs -batch -l ~/.emacs -l gnus -f gnus-jog-cache"
 558   (interactive)
 559   (let ((gnus-mark-article-hook nil)
 560         (gnus-expert-user t)
 561         (nnmail-spool-file nil)
 562         (mail-sources nil)
 563         (gnus-use-dribble-file nil)
 564         (gnus-novice-user nil)
 565         (gnus-large-newsgroup nil))
 566     ;; Start Gnus.
 567     (gnus)
 568     ;; Go through all groups...
 569     (gnus-group-mark-buffer)
 570     (gnus-group-iterate nil
 571       (lambda (group)
 572         (let (gnus-auto-select-next)
 573           (gnus-summary-read-group group nil t)
 574           ;; ... and enter the articles into the cache.
 575           (when (eq major-mode 'gnus-summary-mode)
 576             (gnus-uu-mark-buffer)
 577             (gnus-cache-enter-article)
 578             (kill-buffer (current-buffer))))))))
 579
 580 (defun gnus-cache-read-active (&optional force)
 581   "Read the cache active file."
 582   (gnus-make-directory gnus-cache-directory)
 583   (if (or (not (file-exists-p gnus-cache-active-file))
 584           (zerop (nth 7 (file-attributes gnus-cache-active-file)))
 585           force)
 586       ;; There is no active file, so we generate one.
 587       (gnus-cache-generate-active)
 588     ;; We simply read the active file.
 589     (save-excursion
 590       (gnus-set-work-buffer)
 591       (nnheader-insert-file-contents gnus-cache-active-file)
 592       (gnus-active-to-gnus-format
 593        nil (setq gnus-cache-active-hashtb
 594                  (gnus-make-hashtable
 595                   (count-lines (point-min) (point-max)))))
 596       (setq gnus-cache-active-altered nil))))
 597
 598 (defun gnus-cache-write-active (&optional force)
 599   "Write the active hashtb to the active file."
 600   (when (or force
 601             (and gnus-cache-active-hashtb
 602                  gnus-cache-active-altered))
 603     (gnus-write-active-file gnus-cache-active-file gnus-cache-active-hashtb t)
 604     ;; Mark the active hashtb as unaltered.
 605     (setq gnus-cache-active-altered nil)))
 606
 607 (defun gnus-cache-update-active (group number &optional low)
 608   "Update the upper bound of the active info of GROUP to NUMBER.
 609 If LOW, update the lower bound instead."
 610   (let ((active (gnus-gethash group gnus-cache-active-hashtb)))
 611     (if (null active)
 612         ;; We just create a new active entry for this group.
 613         (gnus-sethash group (cons number number) gnus-cache-active-hashtb)
 614       ;; Update the lower or upper bound.
 615       (if low
 616           (setcar active number)
 617         (setcdr active number)))
 618     ;; Mark the active hashtb as altered.
 619     (setq gnus-cache-active-altered t)))
 620
 621 ;;;###autoload
 622 (defun gnus-cache-generate-active (&optional directory)
 623   "Generate the cache active file."
 624   (interactive)
 625   (let* ((top (null directory))
 626          (directory (expand-file-name (or directory gnus-cache-directory)))
 627          (files (directory-files directory 'full))
 628          (group
 629           (if top
 630               ""
 631             (string-match
 632              (concat "^" (regexp-quote
 633                           (file-name-as-directory
 634                            (expand-file-name gnus-cache-directory))))
 635              (directory-file-name directory))
 636             (nnheader-replace-chars-in-string
 637              (substring (directory-file-name directory) (match-end 0))
 638              ?/ ?.)))
 639          nums alphs)
 640     (when top
 641       (gnus-message 5 "Generating the cache active file...")
 642       (setq gnus-cache-active-hashtb (gnus-make-hashtable 123)))
 643     (when (string-match "^\\(nn[^_]+\\)_" group)
 644       (setq group (replace-match "\\1:" t t group)))
 645     ;; Separate articles from all other files and directories.
 646     (while files
 647       (if (string-match "^[0-9]+$" (file-name-nondirectory (car files)))
 648           (push (string-to-int (file-name-nondirectory (pop files))) nums)
 649         (push (pop files) alphs)))
 650     ;; If we have nums, then this is probably a valid group.
 651     (when (setq nums (sort nums '<))
 652       (gnus-sethash group (cons (car nums) (gnus-last-element nums))
 653                     gnus-cache-active-hashtb))
 654     ;; Go through all the other files.
 655     (while alphs
 656       (when (and (file-directory-p (car alphs))
 657                  (not (string-match "^\\."
 658                                     (file-name-nondirectory (car alphs)))))
 659         ;; We descend directories.
 660         (gnus-cache-generate-active (car alphs)))
 661       (setq alphs (cdr alphs)))
 662     ;; Write the new active file.
 663     (when top
 664       (gnus-cache-write-active t)
 665       (gnus-message 5 "Generating the cache active file...done"))))
 666
 667 ;;;###autoload
 668 (defun gnus-cache-generate-nov-databases (dir)
 669   "Generate NOV files recursively starting in DIR."
 670   (interactive (list gnus-cache-directory))
 671   (gnus-cache-close)
 672   (let ((nnml-generate-active-function 'identity))
 673     (nnml-generate-nov-databases-1 dir)))
 674
 675 (defun gnus-cache-move-cache (dir)
 676   "Move the cache tree to somewhere else."
 677   (interactive "FMove the cache tree to: ")
 678   (rename-file gnus-cache-directory dir))
 679
 680 (provide 'gnus-cache)
 681
 682 ;;; arch-tag: 05a79442-8c58-4e65-bd0a-3cbb1b89a33a
 683 ;;; gnus-cache.el ends here