lisp/gnus/gnus-cache.el

   1 ;;; gnus-cache.el --- cache interface for Gnus
   2
   3 ;; Copyright (C) 1995-2015 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 (eval-when-compile (require 'cl))
  28
  29 (require 'gnus)
  30 (require 'gnus-sum)
  31
  32 (eval-when-compile
  33   (unless (fboundp 'gnus-agent-load-alist)
  34     (defun gnus-agent-load-alist (group))))
  35
  36 (defcustom gnus-cache-active-file
  37   (expand-file-name "active" gnus-cache-directory)
  38   "*The cache active file."
  39   :group 'gnus-cache
  40   :type 'file)
  41
  42 (defcustom gnus-cache-enter-articles '(ticked dormant)
  43   "Classes of articles to enter into the cache."
  44   :group 'gnus-cache
  45   :type '(set (const ticked) (const dormant) (const unread) (const read)))
  46
  47 (defcustom gnus-cache-remove-articles '(read)
  48   "Classes of articles to remove from the cache."
  49   :group 'gnus-cache
  50   :type '(set (const ticked) (const dormant) (const unread) (const read)))
  51
  52 (defcustom gnus-cacheable-groups nil
  53   "*Groups that match this regexp will be cached.
  54
  55 If you only want to cache your nntp groups, you could set this
  56 variable to \"^nntp\".
  57
  58 If a group matches both gnus-cacheable-groups and gnus-uncacheable-groups
  59 it's not cached."
  60   :group 'gnus-cache
  61   :type '(choice (const :tag "off" nil)
  62                  regexp))
  63
  64 (defcustom gnus-uncacheable-groups nil
  65   "*Groups that match this regexp will not be cached.
  66
  67 If you want to avoid caching your nnml groups, you could set this
  68 variable to \"^nnml\".
  69
  70 If a group matches both gnus-cacheable-groups and gnus-uncacheable-groups
  71 it's not cached."
  72   :group 'gnus-cache
  73   :type '(choice (const :tag "off" nil)
  74                  regexp))
  75
  76 (defvar gnus-cache-overview-coding-system 'raw-text
  77   "Coding system used on Gnus cache files.")
  78
  79 (defvar gnus-cache-coding-system 'raw-text
  80   "Coding system used on Gnus cache files.")
  81
  82 \f
  83
  84 ;;; Internal variables.
  85
  86 (defvar gnus-cache-removable-articles nil)
  87 (defvar gnus-cache-buffer nil)
  88 (defvar gnus-cache-active-hashtb nil)
  89 (defvar gnus-cache-active-altered nil)
  90 (defvar gnus-cache-total-fetched-hashtb nil)
  91
  92 (declare-function nnvirtual-find-group-art "nnvirtual" (group article))
  93
  94 (autoload 'nnml-generate-nov-databases-directory "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 (and (buffer-live-p buffer) (buffer-modified-p buffer))
 127         (with-current-buffer buffer
 128           (if (> (buffer-size) 0)
 129               ;; Non-empty overview, write it to a file.
 130               (let ((coding-system-for-write
 131                      gnus-cache-overview-coding-system))
 132                 (gnus-write-buffer overview-file))
 133             (let ((file-name-coding-system nnmail-pathname-coding-system))
 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))))
 144
 145           (gnus-cache-update-overview-total-fetched-for
 146            (car gnus-cache-buffer) overview-file)))
 147       ;; Kill the buffer -- it's either unmodified or saved.
 148       (gnus-kill-buffer buffer)
 149       (setq gnus-cache-buffer nil))))
 150
 151 (defun gnus-cache-possibly-enter-article
 152   (group article ticked dormant unread &optional force)
 153   (when (and (or force (not (eq gnus-use-cache 'passive)))
 154              (numberp article)
 155              (> article 0))             ; This might be a dummy article.
 156     (let ((number article)
 157           file headers lines-chars
 158           (file-name-coding-system nnmail-pathname-coding-system))
 159       ;; If this is a virtual group, we find the real group.
 160       (when (gnus-virtual-group-p group)
 161         (let ((result (nnvirtual-find-group-art
 162                        (gnus-group-real-name group) article)))
 163           (setq group (car result)
 164                 number (cdr result))))
 165       (when (and number
 166                  (> number 0)           ; Reffed article.
 167                  (or force
 168                      (and (gnus-cache-fully-p group)
 169                           (gnus-cache-member-of-class
 170                            gnus-cache-enter-articles ticked dormant unread)))
 171                  (not (file-exists-p (setq file (gnus-cache-file-name
 172                                                  group number)))))
 173         ;; Possibly create the cache directory.
 174         (gnus-make-directory (file-name-directory file))
 175         ;; Save the article in the cache.
 176         (if (file-exists-p file)
 177             t                           ; The article already is saved.
 178           (with-current-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                 (gnus-cache-update-file-total-fetched-for group file))
 187               (setq lines-chars (nnheader-get-lines-and-char))
 188               (nnheader-remove-body)
 189               (setq headers (nnheader-parse-naked-head))
 190               (mail-header-set-number headers number)
 191               (mail-header-set-lines headers (car lines-chars))
 192               (mail-header-set-chars headers (cadr lines-chars))
 193               (gnus-cache-change-buffer group)
 194               (set-buffer (cdr gnus-cache-buffer))
 195               (goto-char (point-max))
 196               (forward-line -1)
 197               (while (condition-case ()
 198                          (when (not (bobp))
 199                            (> (read (current-buffer)) number))
 200                        (error
 201                         ;; The line was malformed, so we just remove it!!
 202                         (gnus-delete-line)
 203                         t))
 204                 (forward-line -1))
 205               (if (bobp)
 206                   (if (not (eobp))
 207                       (progn
 208                         (beginning-of-line)
 209                         (when (< (read (current-buffer)) number)
 210                           (forward-line 1)))
 211                     (beginning-of-line))
 212                 (forward-line 1))
 213               (beginning-of-line)
 214               (nnheader-insert-nov headers)
 215               ;; Update the active info.
 216               (set-buffer gnus-summary-buffer)
 217               (gnus-cache-possibly-update-active group (cons number number))
 218               (setq gnus-newsgroup-cached
 219                     (gnus-add-to-sorted-list gnus-newsgroup-cached article))
 220               (gnus-summary-update-secondary-mark article))
 221             t))))))
 222
 223 (defun gnus-cache-enter-remove-article (article)
 224   "Mark ARTICLE for later possible removal."
 225   (when article
 226     (push article gnus-cache-removable-articles)))
 227
 228 (defun gnus-cache-possibly-remove-articles ()
 229   "Possibly remove some of the removable articles."
 230   (if (not (gnus-virtual-group-p gnus-newsgroup-name))
 231       (gnus-cache-possibly-remove-articles-1)
 232     (let ((arts gnus-cache-removable-articles)
 233           ga)
 234       (while arts
 235         (when (setq ga (nnvirtual-find-group-art
 236                         (gnus-group-real-name gnus-newsgroup-name) (pop arts)))
 237           (let ((gnus-cache-removable-articles (list (cdr ga)))
 238                 (gnus-newsgroup-name (car ga)))
 239             (gnus-cache-possibly-remove-articles-1)))))
 240     (setq gnus-cache-removable-articles nil)))
 241
 242 (defun gnus-cache-possibly-remove-articles-1 ()
 243   "Possibly remove some of the removable articles."
 244   (when (gnus-cache-fully-p gnus-newsgroup-name)
 245     (let ((cache-articles gnus-newsgroup-cached))
 246       (gnus-cache-change-buffer gnus-newsgroup-name)
 247       (dolist (article gnus-cache-removable-articles)
 248         (when (memq article cache-articles)
 249           ;; The article was in the cache, so we see whether we are
 250           ;; supposed to remove it from the cache.
 251           (gnus-cache-possibly-remove-article
 252            article (memq article gnus-newsgroup-marked)
 253            (memq article gnus-newsgroup-dormant)
 254            (or (memq article gnus-newsgroup-unreads)
 255                (memq article gnus-newsgroup-unselected))))))
 256     ;; The overview file might have been modified, save it
 257     ;; safe because we're only called at group exit anyway.
 258     (gnus-cache-save-buffers)))
 259
 260 (defun gnus-cache-request-article (article group)
 261   "Retrieve ARTICLE in GROUP from the cache."
 262   (let ((file (gnus-cache-file-name group article))
 263         (buffer-read-only nil)
 264         (file-name-coding-system nnmail-pathname-coding-system))
 265     (when (file-exists-p file)
 266       (erase-buffer)
 267       (gnus-kill-all-overlays)
 268       (let ((coding-system-for-read gnus-cache-coding-system))
 269         (insert-file-contents file))
 270       t)))
 271
 272 (defun gnus-cache-possibly-alter-active (group active)
 273   "Alter the ACTIVE info for GROUP to reflect the articles in the cache."
 274   (when gnus-cache-active-hashtb
 275     (let ((cache-active (gnus-gethash group gnus-cache-active-hashtb)))
 276       (when cache-active
 277         (when (< (car cache-active) (car active))
 278           (setcar active (car cache-active)))
 279         (when (> (cdr cache-active) (cdr active))
 280           (setcdr active (cdr cache-active)))))))
 281
 282 (defun gnus-cache-retrieve-headers (articles group &optional fetch-old)
 283   "Retrieve the headers for ARTICLES in GROUP."
 284   (let ((cached
 285          (setq gnus-newsgroup-cached (gnus-cache-articles-in-group group))))
 286     (if (not cached)
 287         ;; No cached articles here, so we just retrieve them
 288         ;; the normal way.
 289         (let ((gnus-use-cache nil))
 290           (gnus-retrieve-headers articles group fetch-old))
 291       (let ((uncached-articles (gnus-sorted-difference articles cached))
 292             (cache-file (gnus-cache-file-name group ".overview"))
 293             type
 294             (file-name-coding-system nnmail-pathname-coding-system))
 295         ;; We first retrieve all the headers that we don't have in
 296         ;; the cache.
 297         (let ((gnus-use-cache nil))
 298           (when uncached-articles
 299             (setq type (and articles
 300                             (gnus-retrieve-headers
 301                              uncached-articles group fetch-old)))))
 302         (gnus-cache-save-buffers)
 303         ;; Then we insert the cached headers.
 304         (save-excursion
 305           (cond
 306            ((not (file-exists-p cache-file))
 307             ;; There are no cached headers.
 308             type)
 309            ((null type)
 310             ;; There were no uncached headers (or retrieval was
 311             ;; unsuccessful), so we use the cached headers exclusively.
 312             (set-buffer nntp-server-buffer)
 313             (erase-buffer)
 314             (let ((coding-system-for-read
 315                    gnus-cache-overview-coding-system))
 316               (insert-file-contents cache-file))
 317             'nov)
 318            ((eq type 'nov)
 319             ;; We have both cached and uncached NOV headers, so we
 320             ;; braid them.
 321             (gnus-cache-braid-nov group cached)
 322             type)
 323            (t
 324             ;; We braid HEADs.
 325             (gnus-cache-braid-heads group (gnus-sorted-intersection
 326                                            cached articles))
 327             type)))))))
 328
 329 (defun gnus-cache-enter-article (&optional n)
 330   "Enter the next N articles into the cache.
 331 If not given a prefix, use the process marked articles instead.
 332 Returns the list of articles entered."
 333   (interactive "P")
 334   (let (out)
 335     (dolist (article (gnus-summary-work-articles n))
 336       (gnus-summary-remove-process-mark article)
 337       (if (natnump article)
 338           (when (gnus-cache-possibly-enter-article
 339                  gnus-newsgroup-name article
 340                  nil nil nil t)
 341             (setq gnus-newsgroup-undownloaded (delq article gnus-newsgroup-undownloaded))
 342             (push article out))
 343         (gnus-message 2 "Can't cache article %d" article))
 344       (gnus-summary-update-download-mark article)
 345       (gnus-summary-update-secondary-mark article))
 346     (gnus-summary-next-subject 1)
 347     (gnus-summary-position-point)
 348     (nreverse out)))
 349
 350 (defun gnus-cache-remove-article (&optional n)
 351   "Remove the next N articles from the cache.
 352 If not given a prefix, use the process marked articles instead.
 353 Returns the list of articles removed."
 354   (interactive "P")
 355   (gnus-cache-change-buffer gnus-newsgroup-name)
 356   (let (out)
 357     (dolist (article (gnus-summary-work-articles n))
 358       (gnus-summary-remove-process-mark article)
 359       (when (gnus-cache-possibly-remove-article article nil nil nil t)
 360         (when gnus-newsgroup-agentized
 361           (let ((alist (gnus-agent-load-alist gnus-newsgroup-name)))
 362             (unless (cdr (assoc article alist))
 363               (setq gnus-newsgroup-undownloaded
 364                     (gnus-add-to-sorted-list
 365                      gnus-newsgroup-undownloaded article)))))
 366         (push article out))
 367       (gnus-summary-update-download-mark article)
 368       (gnus-summary-update-secondary-mark article))
 369     (gnus-summary-next-subject 1)
 370     (gnus-summary-position-point)
 371     (nreverse out)))
 372
 373 (defun gnus-cached-article-p (article)
 374   "Say whether ARTICLE is cached in the current group."
 375   (memq article gnus-newsgroup-cached))
 376
 377 (defun gnus-summary-insert-cached-articles ()
 378   "Insert all the articles cached for this group into the current buffer."
 379   (interactive)
 380   (let ((gnus-verbose (max 6 gnus-verbose)))
 381     (cond
 382      ((not gnus-newsgroup-cached)
 383       (gnus-message 3 "No cached articles for this group"))
 384      ;; This is faster if there are few articles to insert.
 385      ((< (length gnus-newsgroup-cached) 20)
 386       (gnus-summary-goto-subjects gnus-newsgroup-cached))
 387      (t
 388       (gnus-summary-include-articles gnus-newsgroup-cached)))))
 389
 390 (defun gnus-summary-limit-include-cached ()
 391   "Limit the summary buffer to articles that are cached."
 392   (interactive)
 393   (let ((gnus-verbose (max 6 gnus-verbose)))
 394     (if gnus-newsgroup-cached
 395         (progn
 396           (gnus-summary-limit gnus-newsgroup-cached)
 397           (gnus-summary-position-point))
 398       (gnus-message 3 "No cached articles for this group"))))
 399
 400 ;;; Internal functions.
 401
 402 (defun gnus-cache-change-buffer (group)
 403   (and gnus-cache-buffer
 404        ;; See if the current group's overview cache has been loaded.
 405        (or (string= group (car gnus-cache-buffer))
 406            ;; Another overview cache is current, save it.
 407            (gnus-cache-save-buffers)))
 408   ;; if gnus-cache buffer is nil, create it
 409   (unless gnus-cache-buffer
 410     ;; Create cache buffer
 411     (save-excursion
 412       (setq gnus-cache-buffer
 413             (cons group
 414                   (set-buffer (gnus-get-buffer-create
 415                                " *gnus-cache-overview*"))))
 416       ;; Insert the contents of this group's cache overview.
 417       (erase-buffer)
 418       (let ((file (gnus-cache-file-name group ".overview"))
 419             (file-name-coding-system nnmail-pathname-coding-system))
 420         (when (file-exists-p file)
 421           (nnheader-insert-file-contents file)))
 422       ;; We have a fresh (empty/just loaded) buffer,
 423       ;; mark it as unmodified to save a redundant write later.
 424       (set-buffer-modified-p nil))))
 425
 426 ;; Return whether an article is a member of a class.
 427 (defun gnus-cache-member-of-class (class ticked dormant unread)
 428   (or (and ticked (memq 'ticked class))
 429       (and dormant (memq 'dormant class))
 430       (and unread (memq 'unread class))
 431       (and (not unread) (not ticked) (not dormant) (memq 'read class))))
 432
 433 (defvar gnus-cache-decoded-group-names nil
 434   "Alist of original group names and decoded group names.
 435 Decoding is done according to `gnus-group-name-charset-method-alist'
 436 or `gnus-group-name-charset-group-alist'.")
 437
 438 (defvar gnus-cache-unified-group-names nil
 439   "Alist of unified decoded group names and original group names.
 440 A group name is decoded according to
 441 `gnus-group-name-charset-method-alist' or
 442 `gnus-group-name-charset-group-alist' first, and is encoded and
 443 decoded again according to `nnmail-pathname-coding-system',
 444 `file-name-coding-system', or `default-file-name-coding-system'.
 445
 446 It is used when asking for a original group name from a cache
 447 directory name, in which non-ASCII characters might have been unified
 448 into the ones of a certain charset particularly if the `utf-8' coding
 449 system for example was used.")
 450
 451 (defun gnus-cache-decoded-group-name (group)
 452   "Return a decoded group name of GROUP."
 453   (or (cdr (assoc group gnus-cache-decoded-group-names))
 454       (let ((decoded (gnus-group-decoded-name group))
 455             (coding (or nnmail-pathname-coding-system
 456                         (and (boundp 'file-name-coding-system)
 457                              file-name-coding-system)
 458                         (and (boundp 'default-file-name-coding-system)
 459                              default-file-name-coding-system))))
 460         (push (cons group decoded) gnus-cache-decoded-group-names)
 461         (push (cons (mm-decode-coding-string
 462                      (mm-encode-coding-string decoded coding)
 463                      coding)
 464                     group)
 465               gnus-cache-unified-group-names)
 466         decoded)))
 467
 468 (defun gnus-cache-file-name (group article)
 469   (setq group (gnus-cache-decoded-group-name group))
 470   (expand-file-name
 471    (if (stringp article) article (int-to-string article))
 472    (file-name-as-directory
 473     (expand-file-name
 474      (nnheader-translate-file-chars
 475       (if (gnus-use-long-file-name 'not-cache)
 476           group
 477         (let ((group (nnheader-replace-duplicate-chars-in-string
 478                       (nnheader-replace-chars-in-string group ?/ ?_)
 479                       ?. ?_)))
 480           ;; Translate the first colon into a slash.
 481           (when (string-match ":" group)
 482                   (setq group (concat (substring group 0 (match-beginning 0))
 483                                       "/" (substring group (match-end 0)))))
 484           (nnheader-replace-chars-in-string group ?. ?/)))
 485       t)
 486      gnus-cache-directory))))
 487
 488 (defun gnus-cache-update-article (group article)
 489   "If ARTICLE is in the cache, remove it and re-enter it."
 490   (gnus-cache-change-buffer group)
 491   (when (gnus-cache-possibly-remove-article article nil nil nil t)
 492     (let ((gnus-use-cache nil))
 493       (gnus-cache-possibly-enter-article
 494        gnus-newsgroup-name article
 495        nil nil nil t))))
 496
 497 (defun gnus-cache-possibly-remove-article (article ticked dormant unread
 498                                                    &optional force)
 499   "Possibly remove ARTICLE from the cache."
 500   (let ((group gnus-newsgroup-name)
 501         (number article)
 502         file
 503         (file-name-coding-system nnmail-pathname-coding-system))
 504     ;; If this is a virtual group, we find the real group.
 505     (when (gnus-virtual-group-p group)
 506       (let ((result (nnvirtual-find-group-art
 507                      (gnus-group-real-name group) article)))
 508         (setq group (car result)
 509               number (cdr result))))
 510     (setq file (gnus-cache-file-name group number))
 511     (when (and (file-exists-p file)
 512                (or force
 513                    (gnus-cache-member-of-class
 514                     gnus-cache-remove-articles ticked dormant unread)))
 515       (save-excursion
 516         (gnus-cache-update-file-total-fetched-for group file t)
 517         (delete-file file)
 518
 519         (set-buffer (cdr gnus-cache-buffer))
 520         (goto-char (point-min))
 521         (when (or (looking-at (concat (int-to-string number) "\t"))
 522                   (search-forward (concat "\n" (int-to-string number) "\t")
 523                                   (point-max) t))
 524             (gnus-delete-line)))
 525       (unless (setq gnus-newsgroup-cached
 526                     (delq article gnus-newsgroup-cached))
 527         (gnus-sethash gnus-newsgroup-name nil gnus-cache-active-hashtb)
 528         (setq gnus-cache-active-altered t))
 529       (gnus-summary-update-secondary-mark article)
 530       t)))
 531
 532 (defun gnus-cache-articles-in-group (group)
 533   "Return a sorted list of cached articles in GROUP."
 534   (let ((dir (file-name-directory (gnus-cache-file-name group 1)))
 535         articles
 536         (file-name-coding-system nnmail-pathname-coding-system))
 537     (when (file-exists-p dir)
 538       (setq articles
 539             (sort (mapcar (lambda (name) (string-to-number name))
 540                           (directory-files dir nil "^[0-9]+$" t))
 541                   '<))
 542       ;; Update the cache active file, just to synch more.
 543       (if articles
 544           (progn
 545             (gnus-cache-update-active group (car articles) t)
 546             (gnus-cache-update-active group (car (last articles))))
 547         (when (gnus-gethash group gnus-cache-active-hashtb)
 548           (gnus-sethash group nil gnus-cache-active-hashtb)
 549           (setq gnus-cache-active-altered t)))
 550       articles)))
 551
 552 (defun gnus-cache-braid-nov (group cached &optional file)
 553   (let ((cache-buf (gnus-get-buffer-create " *gnus-cache*"))
 554         beg end)
 555     (gnus-cache-save-buffers)
 556     (with-current-buffer cache-buf
 557       (erase-buffer)
 558       (let ((coding-system-for-read gnus-cache-overview-coding-system)
 559             (file-name-coding-system nnmail-pathname-coding-system))
 560         (insert-file-contents
 561          (or file (gnus-cache-file-name group ".overview"))))
 562       (goto-char (point-min))
 563       (insert "\n")
 564       (goto-char (point-min)))
 565     (set-buffer nntp-server-buffer)
 566     (goto-char (point-min))
 567     (while cached
 568       (while (and (not (eobp))
 569                   (< (read (current-buffer)) (car cached)))
 570         (forward-line 1))
 571       (beginning-of-line)
 572       (set-buffer cache-buf)
 573       (if (search-forward (concat "\n" (int-to-string (car cached)) "\t")
 574                           nil t)
 575           (setq beg (point-at-bol)
 576                 end (progn (end-of-line) (point)))
 577         (setq beg nil))
 578       (set-buffer nntp-server-buffer)
 579       (when beg
 580         (insert-buffer-substring cache-buf beg end)
 581         (insert "\n"))
 582       (setq cached (cdr cached)))
 583     (kill-buffer cache-buf)))
 584
 585 (defun gnus-cache-braid-heads (group cached)
 586   (let ((cache-buf (gnus-get-buffer-create " *gnus-cache*")))
 587     (with-current-buffer cache-buf
 588       (erase-buffer))
 589     (set-buffer nntp-server-buffer)
 590     (goto-char (point-min))
 591     (dolist (entry cached)
 592       (while (and (not (eobp))
 593                   (looking-at "2.. +\\([0-9]+\\) ")
 594                   (< (progn (goto-char (match-beginning 1))
 595                             (read (current-buffer)))
 596                      entry))
 597         (search-forward "\n.\n" nil 'move))
 598       (beginning-of-line)
 599       (set-buffer cache-buf)
 600       (erase-buffer)
 601       (let ((coding-system-for-read gnus-cache-coding-system)
 602             (file-name-coding-system nnmail-pathname-coding-system))
 603         (insert-file-contents (gnus-cache-file-name group entry)))
 604       (goto-char (point-min))
 605       (insert "220 ")
 606       (princ (pop cached) (current-buffer))
 607       (insert " Article retrieved.\n")
 608       (search-forward "\n\n" nil 'move)
 609       (delete-region (point) (point-max))
 610       (forward-char -1)
 611       (insert ".")
 612       (set-buffer nntp-server-buffer)
 613       (insert-buffer-substring cache-buf))
 614     (kill-buffer cache-buf)))
 615
 616 ;;;###autoload
 617 (defun gnus-jog-cache ()
 618   "Go through all groups and put the articles into the cache.
 619
 620 Usage:
 621 $ emacs -batch -l ~/.emacs -l gnus -f gnus-jog-cache"
 622   (interactive)
 623   (let ((gnus-mark-article-hook nil)
 624         (gnus-expert-user t)
 625         (mail-sources nil)
 626         (gnus-use-dribble-file nil)
 627         (gnus-novice-user nil)
 628         (gnus-large-newsgroup nil))
 629     ;; Start Gnus.
 630     (gnus)
 631     ;; Go through all groups...
 632     (gnus-group-mark-buffer)
 633     (gnus-group-iterate nil
 634       (lambda (group)
 635         (let (gnus-auto-select-next)
 636           (gnus-summary-read-group group nil t)
 637           ;; ... and enter the articles into the cache.
 638           (when (eq major-mode 'gnus-summary-mode)
 639             (gnus-uu-mark-buffer)
 640             (gnus-cache-enter-article)
 641             (kill-buffer (current-buffer))))))))
 642
 643 (defun gnus-cache-read-active (&optional force)
 644   "Read the cache active file."
 645   (gnus-make-directory gnus-cache-directory)
 646   (if (or (not (file-exists-p gnus-cache-active-file))
 647           (zerop (nth 7 (file-attributes gnus-cache-active-file)))
 648           force)
 649       ;; There is no active file, so we generate one.
 650       (gnus-cache-generate-active)
 651     ;; We simply read the active file.
 652     (save-excursion
 653       (gnus-set-work-buffer)
 654       (nnheader-insert-file-contents gnus-cache-active-file)
 655       (gnus-active-to-gnus-format
 656        nil (setq gnus-cache-active-hashtb
 657                  (gnus-make-hashtable
 658                   (count-lines (point-min) (point-max)))))
 659       (setq gnus-cache-active-altered nil))))
 660
 661 (defun gnus-cache-write-active (&optional force)
 662   "Write the active hashtb to the active file."
 663   (when (or force
 664             (and gnus-cache-active-hashtb
 665                  gnus-cache-active-altered))
 666     (gnus-write-active-file gnus-cache-active-file gnus-cache-active-hashtb t)
 667     ;; Mark the active hashtb as unaltered.
 668     (setq gnus-cache-active-altered nil)))
 669
 670 (defun gnus-cache-possibly-update-active (group active)
 671   "Update active info bounds of GROUP with ACTIVE if necessary.
 672 The update is performed if ACTIVE contains a higher or lower bound
 673 than the current."
 674   (let ((lower t) (higher t))
 675     (if gnus-cache-active-hashtb
 676         (let ((cache-active (gnus-gethash group gnus-cache-active-hashtb)))
 677           (when cache-active
 678             (unless (< (car active) (car cache-active))
 679               (setq lower nil))
 680             (unless (> (cdr active) (cdr cache-active))
 681               (setq higher nil))))
 682       (gnus-cache-read-active))
 683     (when lower
 684       (gnus-cache-update-active group (car active) t))
 685     (when higher
 686       (gnus-cache-update-active group (cdr active)))))
 687
 688 (defun gnus-cache-update-active (group number &optional low)
 689   "Update the upper bound of the active info of GROUP to NUMBER.
 690 If LOW, update the lower bound instead."
 691   (let ((active (gnus-gethash group gnus-cache-active-hashtb)))
 692     (if (null active)
 693         ;; We just create a new active entry for this group.
 694         (gnus-sethash group (cons number number) gnus-cache-active-hashtb)
 695       ;; Update the lower or upper bound.
 696       (if low
 697           (setcar active number)
 698         (setcdr active number)))
 699     ;; Mark the active hashtb as altered.
 700     (setq gnus-cache-active-altered t)))
 701
 702 ;;;###autoload
 703 (defun gnus-cache-generate-active (&optional directory)
 704   "Generate the cache active file."
 705   (interactive)
 706   (let* ((top (null directory))
 707          (directory (expand-file-name (or directory gnus-cache-directory)))
 708          (file-name-coding-system nnmail-pathname-coding-system)
 709          (files (directory-files directory 'full))
 710          (group
 711           (if top
 712               ""
 713             (string-match
 714              (concat "^" (regexp-quote
 715                           (file-name-as-directory
 716                            (expand-file-name gnus-cache-directory))))
 717              (directory-file-name directory))
 718             (nnheader-replace-chars-in-string
 719              (substring (directory-file-name directory) (match-end 0))
 720              ?/ ?.)))
 721          nums alphs)
 722     (when top
 723       (gnus-message 5 "Generating the cache active file...")
 724       (setq gnus-cache-active-hashtb (gnus-make-hashtable 123)))
 725     (when (string-match "^\\(nn[^_]+\\)_" group)
 726       (setq group (replace-match "\\1:" t nil group)))
 727     ;; Separate articles from all other files and directories.
 728     (while files
 729       (if (string-match "^[0-9]+$" (file-name-nondirectory (car files)))
 730           (push (string-to-number (file-name-nondirectory (pop files))) nums)
 731         (push (pop files) alphs)))
 732     ;; If we have nums, then this is probably a valid group.
 733     (when (setq nums (sort nums '<))
 734       ;; Use non-decoded group name.
 735       ;; FIXME: this is kind of a workaround.  The active file should
 736       ;; be updated at the time articles are cached.  It will make
 737       ;; `gnus-cache-unified-group-names' needless.
 738       (gnus-sethash (or (cdr (assoc group gnus-cache-unified-group-names))
 739                         group)
 740                     (cons (car nums) (gnus-last-element nums))
 741                     gnus-cache-active-hashtb))
 742     ;; Go through all the other files.
 743     (dolist (file alphs)
 744       (when (and (file-directory-p file)
 745                  (not (string-match "^\\."
 746                                     (file-name-nondirectory file))))
 747         ;; We descend directories.
 748         (gnus-cache-generate-active file)))
 749     ;; Write the new active file.
 750     (when top
 751       (gnus-cache-write-active t)
 752       (gnus-message 5 "Generating the cache active file...done"))))
 753
 754 ;;;###autoload
 755 (defun gnus-cache-generate-nov-databases (dir)
 756   "Generate NOV files recursively starting in DIR."
 757   (interactive (list gnus-cache-directory))
 758   (gnus-cache-close)
 759   (let ((nnml-generate-active-function 'identity))
 760     (nnml-generate-nov-databases-directory dir))
 761
 762   (setq gnus-cache-total-fetched-hashtb nil)
 763
 764   (gnus-cache-open))
 765
 766 (defun gnus-cache-move-cache (dir)
 767   "Move the cache tree to somewhere else."
 768   (interactive "FMove the cache tree to: ")
 769   (rename-file gnus-cache-directory dir))
 770
 771 (defun gnus-cache-fully-p (&optional group)
 772   "Returns non-nil if the cache should be fully used.
 773 If GROUP is non-nil, also cater to `gnus-cacheable-groups' and
 774 `gnus-uncacheable-groups'."
 775   (and gnus-use-cache
 776        (not (eq gnus-use-cache 'passive))
 777        (if (null group)
 778            t
 779          (and (or (not gnus-cacheable-groups)
 780                   (string-match gnus-cacheable-groups group))
 781               (or (not gnus-uncacheable-groups)
 782                   (not (string-match gnus-uncacheable-groups group)))))))
 783
 784 ;;;###autoload
 785 (defun gnus-cache-rename-group (old-group new-group)
 786   "Rename OLD-GROUP as NEW-GROUP.
 787 Always updates the cache, even when disabled, as the old cache
 788 files would corrupt Gnus when the cache was next enabled.  It
 789 depends on the caller to determine whether group renaming is
 790 supported."
 791   (let ((old-dir (gnus-cache-file-name old-group ""))
 792         (new-dir (gnus-cache-file-name new-group ""))
 793         (file-name-coding-system nnmail-pathname-coding-system))
 794     (gnus-rename-file old-dir new-dir t))
 795
 796   (gnus-cache-rename-group-total-fetched-for old-group new-group)
 797
 798   (let ((no-save gnus-cache-active-hashtb))
 799     (unless gnus-cache-active-hashtb
 800       (gnus-cache-read-active))
 801     (let* ((old-group-hash-value
 802             (gnus-gethash old-group gnus-cache-active-hashtb))
 803            (new-group-hash-value
 804             (gnus-gethash new-group gnus-cache-active-hashtb))
 805            (delta
 806             (or old-group-hash-value new-group-hash-value)))
 807       (gnus-sethash new-group old-group-hash-value gnus-cache-active-hashtb)
 808       (gnus-sethash old-group nil gnus-cache-active-hashtb)
 809
 810       (if no-save
 811           (setq gnus-cache-active-altered delta)
 812         (gnus-cache-write-active delta)))))
 813
 814 ;;;###autoload
 815 (defun gnus-cache-delete-group (group)
 816   "Delete GROUP from the cache.
 817 Always updates the cache, even when disabled, as the old cache
 818 files would corrupt gnus when the cache was next enabled.
 819 Depends upon the caller to determine whether group deletion is
 820 supported."
 821   (let ((dir (gnus-cache-file-name group ""))
 822         (file-name-coding-system nnmail-pathname-coding-system))
 823     (gnus-delete-directory dir))
 824
 825   (gnus-cache-delete-group-total-fetched-for group)
 826
 827   (let ((no-save gnus-cache-active-hashtb))
 828     (unless gnus-cache-active-hashtb
 829       (gnus-cache-read-active))
 830     (let* ((group-hash-value (gnus-gethash group gnus-cache-active-hashtb)))
 831       (gnus-sethash group nil gnus-cache-active-hashtb)
 832
 833       (if no-save
 834           (setq gnus-cache-active-altered group-hash-value)
 835         (gnus-cache-write-active group-hash-value)))))
 836
 837 (defvar gnus-cache-inhibit-update-total-fetched-for nil)
 838 (defvar gnus-cache-need-update-total-fetched-for nil)
 839
 840 (defmacro gnus-cache-with-refreshed-group (group &rest body)
 841   `(prog1 (let ((gnus-cache-inhibit-update-total-fetched-for t))
 842             ,@body)
 843      (when (and gnus-cache-need-update-total-fetched-for
 844                 (not gnus-cache-inhibit-update-total-fetched-for))
 845         (with-current-buffer gnus-group-buffer
 846           (setq gnus-cache-need-update-total-fetched-for nil)
 847           (gnus-group-update-group ,group t)))))
 848
 849 (defun gnus-cache-update-file-total-fetched-for (group file &optional subtract)
 850   (when gnus-cache-total-fetched-hashtb
 851     (gnus-cache-with-refreshed-group
 852      group
 853      (let* ((entry (or (gnus-gethash group gnus-cache-total-fetched-hashtb)
 854                        (gnus-sethash group (make-vector 2 0)
 855                                      gnus-cache-total-fetched-hashtb)))
 856             size)
 857
 858        (if file
 859            (setq size (or (nth 7 (file-attributes file)) 0))
 860          (let* ((file-name-coding-system nnmail-pathname-coding-system)
 861                 (files (directory-files (gnus-cache-file-name group "")
 862                                         t nil t))
 863                 file attrs)
 864            (setq size 0.0)
 865            (while (setq file (pop files))
 866              (setq attrs (file-attributes file))
 867              (unless (nth 0 attrs)
 868                (incf size (float (nth 7 attrs)))))))
 869
 870        (setq gnus-cache-need-update-total-fetched-for t)
 871
 872        (incf (nth 1 entry) (if subtract (- size) size))))))
 873
 874 (defun gnus-cache-update-overview-total-fetched-for (group file)
 875   (when gnus-cache-total-fetched-hashtb
 876     (gnus-cache-with-refreshed-group
 877      group
 878      (let* ((entry (or (gnus-gethash group gnus-cache-total-fetched-hashtb)
 879                        (gnus-sethash group (make-list 2 0)
 880                                      gnus-cache-total-fetched-hashtb)))
 881             (file-name-coding-system nnmail-pathname-coding-system)
 882             (size (or (nth 7 (file-attributes
 883                               (or file
 884                                   (gnus-cache-file-name group ".overview"))))
 885                       0)))
 886        (setq gnus-cache-need-update-total-fetched-for t)
 887        (setf (nth 0 entry) size)))))
 888
 889 (defun gnus-cache-rename-group-total-fetched-for (old-group new-group)
 890   "Record of disk space used by OLD-GROUP now associated with NEW-GROUP."
 891   (when gnus-cache-total-fetched-hashtb
 892     (let ((entry (gnus-gethash old-group gnus-cache-total-fetched-hashtb)))
 893       (gnus-sethash new-group entry gnus-cache-total-fetched-hashtb)
 894       (gnus-sethash old-group nil gnus-cache-total-fetched-hashtb))))
 895
 896 (defun gnus-cache-delete-group-total-fetched-for (group)
 897   "Delete record of disk space used by GROUP being deleted."
 898   (when gnus-cache-total-fetched-hashtb
 899       (gnus-sethash group nil gnus-cache-total-fetched-hashtb)))
 900
 901 (defun gnus-cache-total-fetched-for (group &optional no-inhibit)
 902   "Get total disk space used by the cache for the specified GROUP."
 903   (unless (equal group "dummy.group")
 904     (unless gnus-cache-total-fetched-hashtb
 905       (setq gnus-cache-total-fetched-hashtb (gnus-make-hashtable 1024)))
 906
 907     (let* ((entry (gnus-gethash group gnus-cache-total-fetched-hashtb)))
 908       (if entry
 909           (apply '+ entry)
 910         (let ((gnus-cache-inhibit-update-total-fetched-for (not no-inhibit)))
 911           (+
 912            (gnus-cache-update-overview-total-fetched-for group nil)
 913            (gnus-cache-update-file-total-fetched-for     group nil)))))))
 914
 915 (provide 'gnus-cache)
 916
 917 ;;; gnus-cache.el ends here