lisp/gnus/gnus-cache.el

   1 ;;; gnus-cache.el --- cache interface for Gnus
   2
   3 ;; Copyright (C) 1995-2014 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 3 of the License, or
  13 ;; (at your option) 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.  If not, see <http://www.gnu.org/licenses/>.
  22
  23 ;;; Commentary:
  24
  25 ;;; Code:
  26
  27 ;; For Emacs <22.2 and XEmacs.
  28 (eval-and-compile
  29   (unless (fboundp 'declare-function) (defmacro declare-function (&rest r))))
  30
  31 (eval-when-compile (require 'cl))
  32
  33 (require 'gnus)
  34 (require 'gnus-sum)
  35
  36 (eval-when-compile
  37   (unless (fboundp 'gnus-agent-load-alist)
  38     (defun gnus-agent-load-alist (group))))
  39
  40 (defcustom gnus-cache-active-file
  41   (expand-file-name "active" gnus-cache-directory)
  42   "*The cache active file."
  43   :group 'gnus-cache
  44   :type 'file)
  45
  46 (defcustom gnus-cache-enter-articles '(ticked dormant)
  47   "Classes of articles to enter into the cache."
  48   :group 'gnus-cache
  49   :type '(set (const ticked) (const dormant) (const unread) (const read)))
  50
  51 (defcustom gnus-cache-remove-articles '(read)
  52   "Classes of articles to remove from the cache."
  53   :group 'gnus-cache
  54   :type '(set (const ticked) (const dormant) (const unread) (const read)))
  55
  56 (defcustom gnus-cacheable-groups nil
  57   "*Groups that match this regexp will be cached.
  58
  59 If you only want to cache your nntp groups, you could set this
  60 variable to \"^nntp\".
  61
  62 If a group matches both gnus-cacheable-groups and gnus-uncacheable-groups
  63 it's not cached."
  64   :group 'gnus-cache
  65   :type '(choice (const :tag "off" nil)
  66                  regexp))
  67
  68 (defcustom gnus-uncacheable-groups nil
  69   "*Groups that match this regexp will not be cached.
  70
  71 If you want to avoid caching your nnml groups, you could set this
  72 variable to \"^nnml\".
  73
  74 If a group matches both gnus-cacheable-groups and gnus-uncacheable-groups
  75 it's not cached."
  76   :group 'gnus-cache
  77   :type '(choice (const :tag "off" nil)
  78                  regexp))
  79
  80 (defvar gnus-cache-overview-coding-system 'raw-text
  81   "Coding system used on Gnus cache files.")
  82
  83 (defvar gnus-cache-coding-system 'raw-text
  84   "Coding system used on Gnus cache files.")
  85
  86 \f
  87
  88 ;;; Internal variables.
  89
  90 (defvar gnus-cache-removable-articles nil)
  91 (defvar gnus-cache-buffer nil)
  92 (defvar gnus-cache-active-hashtb nil)
  93 (defvar gnus-cache-active-altered nil)
  94 (defvar gnus-cache-total-fetched-hashtb nil)
  95
  96 (declare-function nnvirtual-find-group-art "nnvirtual" (group article))
  97
  98 (autoload 'nnml-generate-nov-databases-directory "nnml")
  99 (autoload 'nnvirtual-find-group-art "nnvirtual")
 100
 101 \f
 102
 103 ;;; Functions called from Gnus.
 104
 105 (defun gnus-cache-open ()
 106   "Initialize the cache."
 107   (when (or (file-exists-p gnus-cache-directory)
 108             (and gnus-use-cache
 109                  (not (eq gnus-use-cache 'passive))))
 110     (gnus-cache-read-active)))
 111
 112 ;; Complexities of byte-compiling make this kludge necessary.  Eeek.
 113 (ignore-errors
 114   (gnus-add-shutdown 'gnus-cache-close 'gnus))
 115
 116 (defun gnus-cache-close ()
 117   "Shut down the cache."
 118   (gnus-cache-write-active)
 119   (gnus-cache-save-buffers)
 120   (setq gnus-cache-active-hashtb nil))
 121
 122 (defun gnus-cache-save-buffers ()
 123   ;; save the overview buffer if it exists and has been modified
 124   ;; delete empty cache subdirectories
 125   (when gnus-cache-buffer
 126     (let ((buffer (cdr gnus-cache-buffer))
 127           (overview-file (gnus-cache-file-name
 128                           (car gnus-cache-buffer) ".overview")))
 129       ;; write the overview only if it was modified
 130       (when (and (buffer-live-p buffer) (buffer-modified-p buffer))
 131         (with-current-buffer buffer
 132           (if (> (buffer-size) 0)
 133               ;; Non-empty overview, write it to a file.
 134               (let ((coding-system-for-write
 135                      gnus-cache-overview-coding-system))
 136                 (gnus-write-buffer overview-file))
 137             (let ((file-name-coding-system nnmail-pathname-coding-system))
 138               ;; Empty overview file, remove it
 139               (when (file-exists-p overview-file)
 140                 (delete-file overview-file))
 141               ;; If possible, remove group's cache subdirectory.
 142               (condition-case nil
 143                   ;; FIXME: we can detect the error type and warn the user
 144                   ;; of any inconsistencies (articles w/o nov entries?).
 145                   ;; for now, just be conservative...delete only if safe -- sj
 146                   (delete-directory (file-name-directory overview-file))
 147                 (error))))
 148
 149           (gnus-cache-update-overview-total-fetched-for
 150            (car gnus-cache-buffer) overview-file)))
 151       ;; Kill the buffer -- it's either unmodified or saved.
 152       (gnus-kill-buffer buffer)
 153       (setq gnus-cache-buffer nil))))
 154
 155 (defun gnus-cache-possibly-enter-article
 156   (group article ticked dormant unread &optional force)
 157   (when (and (or force (not (eq gnus-use-cache 'passive)))
 158              (numberp article)
 159              (> article 0))             ; This might be a dummy article.
 160     (let ((number article)
 161           file headers lines-chars
 162           (file-name-coding-system nnmail-pathname-coding-system))
 163       ;; If this is a virtual group, we find the real group.
 164       (when (gnus-virtual-group-p group)
 165         (let ((result (nnvirtual-find-group-art
 166                        (gnus-group-real-name group) article)))
 167           (setq group (car result)
 168                 number (cdr result))))
 169       (when (and number
 170                  (> number 0)           ; Reffed article.
 171                  (or force
 172                      (and (gnus-cache-fully-p group)
 173                           (gnus-cache-member-of-class
 174                            gnus-cache-enter-articles ticked dormant unread)))
 175                  (not (file-exists-p (setq file (gnus-cache-file-name
 176                                                  group number)))))
 177         ;; Possibly create the cache directory.
 178         (gnus-make-directory (file-name-directory file))
 179         ;; Save the article in the cache.
 180         (if (file-exists-p file)
 181             t                           ; The article already is saved.
 182           (with-current-buffer nntp-server-buffer
 183             (require 'gnus-art)
 184             (let ((gnus-use-cache nil)
 185                   (gnus-article-decode-hook nil))
 186               (gnus-request-article-this-buffer number group))
 187             (when (> (buffer-size) 0)
 188               (let ((coding-system-for-write gnus-cache-coding-system))
 189                 (gnus-write-buffer file)
 190                 (gnus-cache-update-file-total-fetched-for group file))
 191               (setq lines-chars (nnheader-get-lines-and-char))
 192               (nnheader-remove-body)
 193               (setq headers (nnheader-parse-naked-head))
 194               (mail-header-set-number headers number)
 195               (mail-header-set-lines headers (car lines-chars))
 196               (mail-header-set-chars headers (cadr lines-chars))
 197               (gnus-cache-change-buffer group)
 198               (set-buffer (cdr gnus-cache-buffer))
 199               (goto-char (point-max))
 200               (forward-line -1)
 201               (while (condition-case ()
 202                          (when (not (bobp))
 203                            (> (read (current-buffer)) number))
 204                        (error
 205                         ;; The line was malformed, so we just remove it!!
 206                         (gnus-delete-line)
 207                         t))
 208                 (forward-line -1))
 209               (if (bobp)
 210                   (if (not (eobp))
 211                       (progn
 212                         (beginning-of-line)
 213                         (when (< (read (current-buffer)) number)
 214                           (forward-line 1)))
 215                     (beginning-of-line))
 216                 (forward-line 1))
 217               (beginning-of-line)
 218               (nnheader-insert-nov headers)
 219               ;; Update the active info.
 220               (set-buffer gnus-summary-buffer)
 221               (gnus-cache-possibly-update-active group (cons number number))
 222               (setq gnus-newsgroup-cached
 223                     (gnus-add-to-sorted-list gnus-newsgroup-cached article))
 224               (gnus-summary-update-secondary-mark article))
 225             t))))))
 226
 227 (defun gnus-cache-enter-remove-article (article)
 228   "Mark ARTICLE for later possible removal."
 229   (when article
 230     (push article gnus-cache-removable-articles)))
 231
 232 (defun gnus-cache-possibly-remove-articles ()
 233   "Possibly remove some of the removable articles."
 234   (if (not (gnus-virtual-group-p gnus-newsgroup-name))
 235       (gnus-cache-possibly-remove-articles-1)
 236     (let ((arts gnus-cache-removable-articles)
 237           ga)
 238       (while arts
 239         (when (setq ga (nnvirtual-find-group-art
 240                         (gnus-group-real-name gnus-newsgroup-name) (pop arts)))
 241           (let ((gnus-cache-removable-articles (list (cdr ga)))
 242                 (gnus-newsgroup-name (car ga)))
 243             (gnus-cache-possibly-remove-articles-1)))))
 244     (setq gnus-cache-removable-articles nil)))
 245
 246 (defun gnus-cache-possibly-remove-articles-1 ()
 247   "Possibly remove some of the removable articles."
 248   (when (gnus-cache-fully-p gnus-newsgroup-name)
 249     (let ((cache-articles gnus-newsgroup-cached))
 250       (gnus-cache-change-buffer gnus-newsgroup-name)
 251       (dolist (article gnus-cache-removable-articles)
 252         (when (memq article cache-articles)
 253           ;; The article was in the cache, so we see whether we are
 254           ;; supposed to remove it from the cache.
 255           (gnus-cache-possibly-remove-article
 256            article (memq article gnus-newsgroup-marked)
 257            (memq article gnus-newsgroup-dormant)
 258            (or (memq article gnus-newsgroup-unreads)
 259                (memq article gnus-newsgroup-unselected))))))
 260     ;; The overview file might have been modified, save it
 261     ;; safe because we're only called at group exit anyway.
 262     (gnus-cache-save-buffers)))
 263
 264 (defun gnus-cache-request-article (article group)
 265   "Retrieve ARTICLE in GROUP from the cache."
 266   (let ((file (gnus-cache-file-name group article))
 267         (buffer-read-only nil)
 268         (file-name-coding-system nnmail-pathname-coding-system))
 269     (when (file-exists-p file)
 270       (erase-buffer)
 271       (gnus-kill-all-overlays)
 272       (let ((coding-system-for-read gnus-cache-coding-system))
 273         (insert-file-contents file))
 274       t)))
 275
 276 (defun gnus-cache-possibly-alter-active (group active)
 277   "Alter the ACTIVE info for GROUP to reflect the articles in the cache."
 278   (when gnus-cache-active-hashtb
 279     (let ((cache-active (gnus-gethash group gnus-cache-active-hashtb)))
 280       (when cache-active
 281         (when (< (car cache-active) (car active))
 282           (setcar active (car cache-active)))
 283         (when (> (cdr cache-active) (cdr active))
 284           (setcdr active (cdr cache-active)))))))
 285
 286 (defun gnus-cache-retrieve-headers (articles group &optional fetch-old)
 287   "Retrieve the headers for ARTICLES in GROUP."
 288   (let ((cached
 289          (setq gnus-newsgroup-cached (gnus-cache-articles-in-group group))))
 290     (if (not cached)
 291         ;; No cached articles here, so we just retrieve them
 292         ;; the normal way.
 293         (let ((gnus-use-cache nil))
 294           (gnus-retrieve-headers articles group fetch-old))
 295       (let ((uncached-articles (gnus-sorted-difference articles cached))
 296             (cache-file (gnus-cache-file-name group ".overview"))
 297             type
 298             (file-name-coding-system nnmail-pathname-coding-system))
 299         ;; We first retrieve all the headers that we don't have in
 300         ;; the cache.
 301         (let ((gnus-use-cache nil))
 302           (when uncached-articles
 303             (setq type (and articles
 304                             (gnus-retrieve-headers
 305                              uncached-articles group fetch-old)))))
 306         (gnus-cache-save-buffers)
 307         ;; Then we insert the cached headers.
 308         (save-excursion
 309           (cond
 310            ((not (file-exists-p cache-file))
 311             ;; There are no cached headers.
 312             type)
 313            ((null type)
 314             ;; There were no uncached headers (or retrieval was
 315             ;; unsuccessful), so we use the cached headers exclusively.
 316             (set-buffer nntp-server-buffer)
 317             (erase-buffer)
 318             (let ((coding-system-for-read
 319                    gnus-cache-overview-coding-system))
 320               (insert-file-contents cache-file))
 321             'nov)
 322            ((eq type 'nov)
 323             ;; We have both cached and uncached NOV headers, so we
 324             ;; braid them.
 325             (gnus-cache-braid-nov group cached)
 326             type)
 327            (t
 328             ;; We braid HEADs.
 329             (gnus-cache-braid-heads group (gnus-sorted-intersection
 330                                            cached articles))
 331             type)))))))
 332
 333 (defun gnus-cache-enter-article (&optional n)
 334   "Enter the next N articles into the cache.
 335 If not given a prefix, use the process marked articles instead.
 336 Returns the list of articles entered."
 337   (interactive "P")
 338   (let (out)
 339     (dolist (article (gnus-summary-work-articles n))
 340       (gnus-summary-remove-process-mark article)
 341       (if (natnump article)
 342           (when (gnus-cache-possibly-enter-article
 343                  gnus-newsgroup-name article
 344                  nil nil nil t)
 345             (setq gnus-newsgroup-undownloaded (delq article gnus-newsgroup-undownloaded))
 346             (push article out))
 347         (gnus-message 2 "Can't cache article %d" article))
 348       (gnus-summary-update-download-mark article)
 349       (gnus-summary-update-secondary-mark article))
 350     (gnus-summary-next-subject 1)
 351     (gnus-summary-position-point)
 352     (nreverse out)))
 353
 354 (defun gnus-cache-remove-article (&optional n)
 355   "Remove the next N articles from the cache.
 356 If not given a prefix, use the process marked articles instead.
 357 Returns the list of articles removed."
 358   (interactive "P")
 359   (gnus-cache-change-buffer gnus-newsgroup-name)
 360   (let (out)
 361     (dolist (article (gnus-summary-work-articles n))
 362       (gnus-summary-remove-process-mark article)
 363       (when (gnus-cache-possibly-remove-article article nil nil nil t)
 364         (when gnus-newsgroup-agentized
 365           (let ((alist (gnus-agent-load-alist gnus-newsgroup-name)))
 366             (unless (cdr (assoc article alist))
 367               (setq gnus-newsgroup-undownloaded
 368                     (gnus-add-to-sorted-list
 369                      gnus-newsgroup-undownloaded article)))))
 370         (push article out))
 371       (gnus-summary-update-download-mark article)
 372       (gnus-summary-update-secondary-mark article))
 373     (gnus-summary-next-subject 1)
 374     (gnus-summary-position-point)
 375     (nreverse out)))
 376
 377 (defun gnus-cached-article-p (article)
 378   "Say whether ARTICLE is cached in the current group."
 379   (memq article gnus-newsgroup-cached))
 380
 381 (defun gnus-summary-insert-cached-articles ()
 382   "Insert all the articles cached for this group into the current buffer."
 383   (interactive)
 384   (let ((gnus-verbose (max 6 gnus-verbose)))
 385     (cond
 386      ((not gnus-newsgroup-cached)
 387       (gnus-message 3 "No cached articles for this group"))
 388      ;; This is faster if there are few articles to insert.
 389      ((< (length gnus-newsgroup-cached) 20)
 390       (gnus-summary-goto-subjects gnus-newsgroup-cached))
 391      (t
 392       (gnus-summary-include-articles gnus-newsgroup-cached)))))
 393
 394 (defun gnus-summary-limit-include-cached ()
 395   "Limit the summary buffer to articles that are cached."
 396   (interactive)
 397   (let ((gnus-verbose (max 6 gnus-verbose)))
 398     (if gnus-newsgroup-cached
 399         (progn
 400           (gnus-summary-limit gnus-newsgroup-cached)
 401           (gnus-summary-position-point))
 402       (gnus-message 3 "No cached articles for this group"))))
 403
 404 ;;; Internal functions.
 405
 406 (defun gnus-cache-change-buffer (group)
 407   (and gnus-cache-buffer
 408        ;; See if the current group's overview cache has been loaded.
 409        (or (string= group (car gnus-cache-buffer))
 410            ;; Another overview cache is current, save it.
 411            (gnus-cache-save-buffers)))
 412   ;; if gnus-cache buffer is nil, create it
 413   (unless gnus-cache-buffer
 414     ;; Create cache buffer
 415     (save-excursion
 416       (setq gnus-cache-buffer
 417             (cons group
 418                   (set-buffer (gnus-get-buffer-create
 419                                " *gnus-cache-overview*"))))
 420       ;; Insert the contents of this group's cache overview.
 421       (erase-buffer)
 422       (let ((file (gnus-cache-file-name group ".overview"))
 423             (file-name-coding-system nnmail-pathname-coding-system))
 424         (when (file-exists-p file)
 425           (nnheader-insert-file-contents file)))
 426       ;; We have a fresh (empty/just loaded) buffer,
 427       ;; mark it as unmodified to save a redundant write later.
 428       (set-buffer-modified-p nil))))
 429
 430 ;; Return whether an article is a member of a class.
 431 (defun gnus-cache-member-of-class (class ticked dormant unread)
 432   (or (and ticked (memq 'ticked class))
 433       (and dormant (memq 'dormant class))
 434       (and unread (memq 'unread class))
 435       (and (not unread) (not ticked) (not dormant) (memq 'read class))))
 436
 437 (defvar gnus-cache-decoded-group-names nil
 438   "Alist of original group names and decoded group names.
 439 Decoding is done according to `gnus-group-name-charset-method-alist'
 440 or `gnus-group-name-charset-group-alist'.")
 441
 442 (defvar gnus-cache-unified-group-names nil
 443   "Alist of unified decoded group names and original group names.
 444 A group name is decoded according to
 445 `gnus-group-name-charset-method-alist' or
 446 `gnus-group-name-charset-group-alist' first, and is encoded and
 447 decoded again according to `nnmail-pathname-coding-system',
 448 `file-name-coding-system', or `default-file-name-coding-system'.
 449
 450 It is used when asking for a original group name from a cache
 451 directory name, in which non-ASCII characters might have been unified
 452 into the ones of a certain charset particularly if the `utf-8' coding
 453 system for example was used.")
 454
 455 (defun gnus-cache-decoded-group-name (group)
 456   "Return a decoded group name of GROUP."
 457   (or (cdr (assoc group gnus-cache-decoded-group-names))
 458       (let ((decoded (gnus-group-decoded-name group))
 459             (coding (or nnmail-pathname-coding-system
 460                         (and (boundp 'file-name-coding-system)
 461                              file-name-coding-system)
 462                         (and (boundp 'default-file-name-coding-system)
 463                              default-file-name-coding-system))))
 464         (push (cons group decoded) gnus-cache-decoded-group-names)
 465         (push (cons (mm-decode-coding-string
 466                      (mm-encode-coding-string decoded coding)
 467                      coding)
 468                     group)
 469               gnus-cache-unified-group-names)
 470         decoded)))
 471
 472 (defun gnus-cache-file-name (group article)
 473   (setq group (gnus-cache-decoded-group-name group))
 474   (expand-file-name
 475    (if (stringp article) article (int-to-string article))
 476    (file-name-as-directory
 477     (expand-file-name
 478      (nnheader-translate-file-chars
 479       (if (gnus-use-long-file-name 'not-cache)
 480           group
 481         (let ((group (nnheader-replace-duplicate-chars-in-string
 482                       (nnheader-replace-chars-in-string group ?/ ?_)
 483                       ?. ?_)))
 484           ;; Translate the first colon into a slash.
 485           (when (string-match ":" group)
 486                   (setq group (concat (substring group 0 (match-beginning 0))
 487                                       "/" (substring group (match-end 0)))))
 488           (nnheader-replace-chars-in-string group ?. ?/)))
 489       t)
 490      gnus-cache-directory))))
 491
 492 (defun gnus-cache-update-article (group article)
 493   "If ARTICLE is in the cache, remove it and re-enter it."
 494   (gnus-cache-change-buffer group)
 495   (when (gnus-cache-possibly-remove-article article nil nil nil t)
 496     (let ((gnus-use-cache nil))
 497       (gnus-cache-possibly-enter-article
 498        gnus-newsgroup-name article
 499        nil nil nil t))))
 500
 501 (defun gnus-cache-possibly-remove-article (article ticked dormant unread
 502                                                    &optional force)
 503   "Possibly remove ARTICLE from the cache."
 504   (let ((group gnus-newsgroup-name)
 505         (number article)
 506         file
 507         (file-name-coding-system nnmail-pathname-coding-system))
 508     ;; If this is a virtual group, we find the real group.
 509     (when (gnus-virtual-group-p group)
 510       (let ((result (nnvirtual-find-group-art
 511                      (gnus-group-real-name group) article)))
 512         (setq group (car result)
 513               number (cdr result))))
 514     (setq file (gnus-cache-file-name group number))
 515     (when (and (file-exists-p file)
 516                (or force
 517                    (gnus-cache-member-of-class
 518                     gnus-cache-remove-articles ticked dormant unread)))
 519       (save-excursion
 520         (gnus-cache-update-file-total-fetched-for group file t)
 521         (delete-file file)
 522
 523         (set-buffer (cdr gnus-cache-buffer))
 524         (goto-char (point-min))
 525         (when (or (looking-at (concat (int-to-string number) "\t"))
 526                   (search-forward (concat "\n" (int-to-string number) "\t")
 527                                   (point-max) t))
 528             (gnus-delete-line)))
 529       (unless (setq gnus-newsgroup-cached
 530                     (delq article gnus-newsgroup-cached))
 531         (gnus-sethash gnus-newsgroup-name nil gnus-cache-active-hashtb)
 532         (setq gnus-cache-active-altered t))
 533       (gnus-summary-update-secondary-mark article)
 534       t)))
 535
 536 (defun gnus-cache-articles-in-group (group)
 537   "Return a sorted list of cached articles in GROUP."
 538   (let ((dir (file-name-directory (gnus-cache-file-name group 1)))
 539         articles
 540         (file-name-coding-system nnmail-pathname-coding-system))
 541     (when (file-exists-p dir)
 542       (setq articles
 543             (sort (mapcar (lambda (name) (string-to-number name))
 544                           (directory-files dir nil "^[0-9]+$" t))
 545                   '<))
 546       ;; Update the cache active file, just to synch more.
 547       (if articles
 548           (progn
 549             (gnus-cache-update-active group (car articles) t)
 550             (gnus-cache-update-active group (car (last articles))))
 551         (when (gnus-gethash group gnus-cache-active-hashtb)
 552           (gnus-sethash group nil gnus-cache-active-hashtb)
 553           (setq gnus-cache-active-altered t)))
 554       articles)))
 555
 556 (defun gnus-cache-braid-nov (group cached &optional file)
 557   (let ((cache-buf (gnus-get-buffer-create " *gnus-cache*"))
 558         beg end)
 559     (gnus-cache-save-buffers)
 560     (with-current-buffer cache-buf
 561       (erase-buffer)
 562       (let ((coding-system-for-read gnus-cache-overview-coding-system)
 563             (file-name-coding-system nnmail-pathname-coding-system))
 564         (insert-file-contents
 565          (or file (gnus-cache-file-name group ".overview"))))
 566       (goto-char (point-min))
 567       (insert "\n")
 568       (goto-char (point-min)))
 569     (set-buffer nntp-server-buffer)
 570     (goto-char (point-min))
 571     (while cached
 572       (while (and (not (eobp))
 573                   (< (read (current-buffer)) (car cached)))
 574         (forward-line 1))
 575       (beginning-of-line)
 576       (set-buffer cache-buf)
 577       (if (search-forward (concat "\n" (int-to-string (car cached)) "\t")
 578                           nil t)
 579           (setq beg (point-at-bol)
 580                 end (progn (end-of-line) (point)))
 581         (setq beg nil))
 582       (set-buffer nntp-server-buffer)
 583       (when beg
 584         (insert-buffer-substring cache-buf beg end)
 585         (insert "\n"))
 586       (setq cached (cdr cached)))
 587     (kill-buffer cache-buf)))
 588
 589 (defun gnus-cache-braid-heads (group cached)
 590   (let ((cache-buf (gnus-get-buffer-create " *gnus-cache*")))
 591     (with-current-buffer cache-buf
 592       (erase-buffer))
 593     (set-buffer nntp-server-buffer)
 594     (goto-char (point-min))
 595     (dolist (entry cached)
 596       (while (and (not (eobp))
 597                   (looking-at "2.. +\\([0-9]+\\) ")
 598                   (< (progn (goto-char (match-beginning 1))
 599                             (read (current-buffer)))
 600                      entry))
 601         (search-forward "\n.\n" nil 'move))
 602       (beginning-of-line)
 603       (set-buffer cache-buf)
 604       (erase-buffer)
 605       (let ((coding-system-for-read gnus-cache-coding-system)
 606             (file-name-coding-system nnmail-pathname-coding-system))
 607         (insert-file-contents (gnus-cache-file-name group entry)))
 608       (goto-char (point-min))
 609       (insert "220 ")
 610       (princ (pop cached) (current-buffer))
 611       (insert " Article retrieved.\n")
 612       (search-forward "\n\n" nil 'move)
 613       (delete-region (point) (point-max))
 614       (forward-char -1)
 615       (insert ".")
 616       (set-buffer nntp-server-buffer)
 617       (insert-buffer-substring cache-buf))
 618     (kill-buffer cache-buf)))
 619
 620 ;;;###autoload
 621 (defun gnus-jog-cache ()
 622   "Go through all groups and put the articles into the cache.
 623
 624 Usage:
 625 $ emacs -batch -l ~/.emacs -l gnus -f gnus-jog-cache"
 626   (interactive)
 627   (let ((gnus-mark-article-hook nil)
 628         (gnus-expert-user t)
 629         (mail-sources nil)
 630         (gnus-use-dribble-file nil)
 631         (gnus-novice-user nil)
 632         (gnus-large-newsgroup nil))
 633     ;; Start Gnus.
 634     (gnus)
 635     ;; Go through all groups...
 636     (gnus-group-mark-buffer)
 637     (gnus-group-iterate nil
 638       (lambda (group)
 639         (let (gnus-auto-select-next)
 640           (gnus-summary-read-group group nil t)
 641           ;; ... and enter the articles into the cache.
 642           (when (eq major-mode 'gnus-summary-mode)
 643             (gnus-uu-mark-buffer)
 644             (gnus-cache-enter-article)
 645             (kill-buffer (current-buffer))))))))
 646
 647 (defun gnus-cache-read-active (&optional force)
 648   "Read the cache active file."
 649   (gnus-make-directory gnus-cache-directory)
 650   (if (or (not (file-exists-p gnus-cache-active-file))
 651           (zerop (nth 7 (file-attributes gnus-cache-active-file)))
 652           force)
 653       ;; There is no active file, so we generate one.
 654       (gnus-cache-generate-active)
 655     ;; We simply read the active file.
 656     (save-excursion
 657       (gnus-set-work-buffer)
 658       (nnheader-insert-file-contents gnus-cache-active-file)
 659       (gnus-active-to-gnus-format
 660        nil (setq gnus-cache-active-hashtb
 661                  (gnus-make-hashtable
 662                   (count-lines (point-min) (point-max)))))
 663       (setq gnus-cache-active-altered nil))))
 664
 665 (defun gnus-cache-write-active (&optional force)
 666   "Write the active hashtb to the active file."
 667   (when (or force
 668             (and gnus-cache-active-hashtb
 669                  gnus-cache-active-altered))
 670     (gnus-write-active-file gnus-cache-active-file gnus-cache-active-hashtb t)
 671     ;; Mark the active hashtb as unaltered.
 672     (setq gnus-cache-active-altered nil)))
 673
 674 (defun gnus-cache-possibly-update-active (group active)
 675   "Update active info bounds of GROUP with ACTIVE if necessary.
 676 The update is performed if ACTIVE contains a higher or lower bound
 677 than the current."
 678   (let ((lower t) (higher t))
 679     (if gnus-cache-active-hashtb
 680         (let ((cache-active (gnus-gethash group gnus-cache-active-hashtb)))
 681           (when cache-active
 682             (unless (< (car active) (car cache-active))
 683               (setq lower nil))
 684             (unless (> (cdr active) (cdr cache-active))
 685               (setq higher nil))))
 686       (gnus-cache-read-active))
 687     (when lower
 688       (gnus-cache-update-active group (car active) t))
 689     (when higher
 690       (gnus-cache-update-active group (cdr active)))))
 691
 692 (defun gnus-cache-update-active (group number &optional low)
 693   "Update the upper bound of the active info of GROUP to NUMBER.
 694 If LOW, update the lower bound instead."
 695   (let ((active (gnus-gethash group gnus-cache-active-hashtb)))
 696     (if (null active)
 697         ;; We just create a new active entry for this group.
 698         (gnus-sethash group (cons number number) gnus-cache-active-hashtb)
 699       ;; Update the lower or upper bound.
 700       (if low
 701           (setcar active number)
 702         (setcdr active number)))
 703     ;; Mark the active hashtb as altered.
 704     (setq gnus-cache-active-altered t)))
 705
 706 ;;;###autoload
 707 (defun gnus-cache-generate-active (&optional directory)
 708   "Generate the cache active file."
 709   (interactive)
 710   (let* ((top (null directory))
 711          (directory (expand-file-name (or directory gnus-cache-directory)))
 712          (file-name-coding-system nnmail-pathname-coding-system)
 713          (files (directory-files directory 'full))
 714          (group
 715           (if top
 716               ""
 717             (string-match
 718              (concat "^" (regexp-quote
 719                           (file-name-as-directory
 720                            (expand-file-name gnus-cache-directory))))
 721              (directory-file-name directory))
 722             (nnheader-replace-chars-in-string
 723              (substring (directory-file-name directory) (match-end 0))
 724              ?/ ?.)))
 725          nums alphs)
 726     (when top
 727       (gnus-message 5 "Generating the cache active file...")
 728       (setq gnus-cache-active-hashtb (gnus-make-hashtable 123)))
 729     (when (string-match "^\\(nn[^_]+\\)_" group)
 730       (setq group (replace-match "\\1:" t nil group)))
 731     ;; Separate articles from all other files and directories.
 732     (while files
 733       (if (string-match "^[0-9]+$" (file-name-nondirectory (car files)))
 734           (push (string-to-number (file-name-nondirectory (pop files))) nums)
 735         (push (pop files) alphs)))
 736     ;; If we have nums, then this is probably a valid group.
 737     (when (setq nums (sort nums '<))
 738       ;; Use non-decoded group name.
 739       ;; FIXME: this is kind of a workaround.  The active file should
 740       ;; be updated at the time articles are cached.  It will make
 741       ;; `gnus-cache-unified-group-names' needless.
 742       (gnus-sethash (or (cdr (assoc group gnus-cache-unified-group-names))
 743                         group)
 744                     (cons (car nums) (gnus-last-element nums))
 745                     gnus-cache-active-hashtb))
 746     ;; Go through all the other files.
 747     (dolist (file alphs)
 748       (when (and (file-directory-p file)
 749                  (not (string-match "^\\."
 750                                     (file-name-nondirectory file))))
 751         ;; We descend directories.
 752         (gnus-cache-generate-active file)))
 753     ;; Write the new active file.
 754     (when top
 755       (gnus-cache-write-active t)
 756       (gnus-message 5 "Generating the cache active file...done"))))
 757
 758 ;;;###autoload
 759 (defun gnus-cache-generate-nov-databases (dir)
 760   "Generate NOV files recursively starting in DIR."
 761   (interactive (list gnus-cache-directory))
 762   (gnus-cache-close)
 763   (let ((nnml-generate-active-function 'identity))
 764     (nnml-generate-nov-databases-directory dir))
 765
 766   (setq gnus-cache-total-fetched-hashtb nil)
 767
 768   (gnus-cache-open))
 769
 770 (defun gnus-cache-move-cache (dir)
 771   "Move the cache tree to somewhere else."
 772   (interactive "FMove the cache tree to: ")
 773   (rename-file gnus-cache-directory dir))
 774
 775 (defun gnus-cache-fully-p (&optional group)
 776   "Returns non-nil if the cache should be fully used.
 777 If GROUP is non-nil, also cater to `gnus-cacheable-groups' and
 778 `gnus-uncacheable-groups'."
 779   (and gnus-use-cache
 780        (not (eq gnus-use-cache 'passive))
 781        (if (null group)
 782            t
 783          (and (or (not gnus-cacheable-groups)
 784                   (string-match gnus-cacheable-groups group))
 785               (or (not gnus-uncacheable-groups)
 786                   (not (string-match gnus-uncacheable-groups group)))))))
 787
 788 ;;;###autoload
 789 (defun gnus-cache-rename-group (old-group new-group)
 790   "Rename OLD-GROUP as NEW-GROUP.
 791 Always updates the cache, even when disabled, as the old cache
 792 files would corrupt Gnus when the cache was next enabled.  It
 793 depends on the caller to determine whether group renaming is
 794 supported."
 795   (let ((old-dir (gnus-cache-file-name old-group ""))
 796         (new-dir (gnus-cache-file-name new-group ""))
 797         (file-name-coding-system nnmail-pathname-coding-system))
 798     (gnus-rename-file old-dir new-dir t))
 799
 800   (gnus-cache-rename-group-total-fetched-for old-group new-group)
 801
 802   (let ((no-save gnus-cache-active-hashtb))
 803     (unless gnus-cache-active-hashtb
 804       (gnus-cache-read-active))
 805     (let* ((old-group-hash-value
 806             (gnus-gethash old-group gnus-cache-active-hashtb))
 807            (new-group-hash-value
 808             (gnus-gethash new-group gnus-cache-active-hashtb))
 809            (delta
 810             (or old-group-hash-value new-group-hash-value)))
 811       (gnus-sethash new-group old-group-hash-value gnus-cache-active-hashtb)
 812       (gnus-sethash old-group nil gnus-cache-active-hashtb)
 813
 814       (if no-save
 815           (setq gnus-cache-active-altered delta)
 816         (gnus-cache-write-active delta)))))
 817
 818 ;;;###autoload
 819 (defun gnus-cache-delete-group (group)
 820   "Delete GROUP from the cache.
 821 Always updates the cache, even when disabled, as the old cache
 822 files would corrupt gnus when the cache was next enabled.
 823 Depends upon the caller to determine whether group deletion is
 824 supported."
 825   (let ((dir (gnus-cache-file-name group ""))
 826         (file-name-coding-system nnmail-pathname-coding-system))
 827     (gnus-delete-directory dir))
 828
 829   (gnus-cache-delete-group-total-fetched-for group)
 830
 831   (let ((no-save gnus-cache-active-hashtb))
 832     (unless gnus-cache-active-hashtb
 833       (gnus-cache-read-active))
 834     (let* ((group-hash-value (gnus-gethash group gnus-cache-active-hashtb)))
 835       (gnus-sethash group nil gnus-cache-active-hashtb)
 836
 837       (if no-save
 838           (setq gnus-cache-active-altered group-hash-value)
 839         (gnus-cache-write-active group-hash-value)))))
 840
 841 (defvar gnus-cache-inhibit-update-total-fetched-for nil)
 842 (defvar gnus-cache-need-update-total-fetched-for nil)
 843
 844 (defmacro gnus-cache-with-refreshed-group (group &rest body)
 845   `(prog1 (let ((gnus-cache-inhibit-update-total-fetched-for t))
 846             ,@body)
 847      (when (and gnus-cache-need-update-total-fetched-for
 848                 (not gnus-cache-inhibit-update-total-fetched-for))
 849         (with-current-buffer gnus-group-buffer
 850           (setq gnus-cache-need-update-total-fetched-for nil)
 851           (gnus-group-update-group ,group t)))))
 852
 853 (defun gnus-cache-update-file-total-fetched-for (group file &optional subtract)
 854   (when gnus-cache-total-fetched-hashtb
 855     (gnus-cache-with-refreshed-group
 856      group
 857      (let* ((entry (or (gnus-gethash group gnus-cache-total-fetched-hashtb)
 858                        (gnus-sethash group (make-vector 2 0)
 859                                      gnus-cache-total-fetched-hashtb)))
 860             size)
 861
 862        (if file
 863            (setq size (or (nth 7 (file-attributes file)) 0))
 864          (let* ((file-name-coding-system nnmail-pathname-coding-system)
 865                 (files (directory-files (gnus-cache-file-name group "")
 866                                         t nil t))
 867                 file attrs)
 868            (setq size 0.0)
 869            (while (setq file (pop files))
 870              (setq attrs (file-attributes file))
 871              (unless (nth 0 attrs)
 872                (incf size (float (nth 7 attrs)))))))
 873
 874        (setq gnus-cache-need-update-total-fetched-for t)
 875
 876        (incf (nth 1 entry) (if subtract (- size) size))))))
 877
 878 (defun gnus-cache-update-overview-total-fetched-for (group file)
 879   (when gnus-cache-total-fetched-hashtb
 880     (gnus-cache-with-refreshed-group
 881      group
 882      (let* ((entry (or (gnus-gethash group gnus-cache-total-fetched-hashtb)
 883                        (gnus-sethash group (make-list 2 0)
 884                                      gnus-cache-total-fetched-hashtb)))
 885             (file-name-coding-system nnmail-pathname-coding-system)
 886             (size (or (nth 7 (file-attributes
 887                               (or file
 888                                   (gnus-cache-file-name group ".overview"))))
 889                       0)))
 890        (setq gnus-cache-need-update-total-fetched-for t)
 891        (setf (nth 0 entry) size)))))
 892
 893 (defun gnus-cache-rename-group-total-fetched-for (old-group new-group)
 894   "Record of disk space used by OLD-GROUP now associated with NEW-GROUP."
 895   (when gnus-cache-total-fetched-hashtb
 896     (let ((entry (gnus-gethash old-group gnus-cache-total-fetched-hashtb)))
 897       (gnus-sethash new-group entry gnus-cache-total-fetched-hashtb)
 898       (gnus-sethash old-group nil gnus-cache-total-fetched-hashtb))))
 899
 900 (defun gnus-cache-delete-group-total-fetched-for (group)
 901   "Delete record of disk space used by GROUP being deleted."
 902   (when gnus-cache-total-fetched-hashtb
 903       (gnus-sethash group nil gnus-cache-total-fetched-hashtb)))
 904
 905 (defun gnus-cache-total-fetched-for (group &optional no-inhibit)
 906   "Get total disk space used by the cache for the specified GROUP."
 907   (unless (equal group "dummy.group")
 908     (unless gnus-cache-total-fetched-hashtb
 909       (setq gnus-cache-total-fetched-hashtb (gnus-make-hashtable 1024)))
 910
 911     (let* ((entry (gnus-gethash group gnus-cache-total-fetched-hashtb)))
 912       (if entry
 913           (apply '+ entry)
 914         (let ((gnus-cache-inhibit-update-total-fetched-for (not no-inhibit)))
 915           (+
 916            (gnus-cache-update-overview-total-fetched-for group nil)
 917            (gnus-cache-update-file-total-fetched-for     group nil)))))))
 918
 919 (provide 'gnus-cache)
 920
 921 ;;; gnus-cache.el ends here