lisp/gnus/gnus-registry.el

   1 ;;; gnus-registry.el --- article registry for Gnus
   2
   3 ;; Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
   4 ;;   2005 Free Software Foundation, Inc.
   5
   6 ;; Author: Ted Zlatanov <tzz@lifelogs.com>
   7 ;; Keywords: news
   8
   9 ;; This file is part of GNU Emacs.
  10
  11 ;; GNU Emacs is free software; you can redistribute it and/or modify
  12 ;; it under the terms of the GNU General Public License as published by
  13 ;; the Free Software Foundation; either version 2, or (at your option)
  14 ;; any later version.
  15
  16 ;; GNU Emacs is distributed in the hope that it will be useful,
  17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 ;; GNU General Public License for more details.
  20
  21 ;; You should have received a copy of the GNU General Public License
  22 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  23 ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  24 ;; Boston, MA 02110-1301, USA.
  25
  26 ;;; Commentary:
  27
  28 ;; This is the gnus-registry.el package, works with other backends
  29 ;; besides nnmail.  The major issue is that it doesn't go across
  30 ;; backends, so for instance if an article is in nnml:sys and you see
  31 ;; a reference to it in nnimap splitting, the article will end up in
  32 ;; nnimap:sys
  33
  34 ;; gnus-registry.el intercepts article respooling, moving, deleting,
  35 ;; and copying for all backends.  If it doesn't work correctly for
  36 ;; you, submit a bug report and I'll be glad to fix it.  It needs
  37 ;; documentation in the manual (also on my to-do list).
  38
  39 ;; Put this in your startup file (~/.gnus.el for instance)
  40
  41 ;; (setq gnus-registry-max-entries 2500
  42 ;;       gnus-registry-use-long-group-names t)
  43
  44 ;; (gnus-registry-initialize)
  45
  46 ;; Then use this in your fancy-split:
  47
  48 ;; (: gnus-registry-split-fancy-with-parent)
  49
  50 ;; TODO:
  51
  52 ;; - get the correct group on spool actions
  53
  54 ;; - articles that are spooled to a different backend should be handled
  55
  56 ;;; Code:
  57
  58 (eval-when-compile (require 'cl))
  59
  60 (require 'gnus)
  61 (require 'gnus-int)
  62 (require 'gnus-sum)
  63 (require 'nnmail)
  64
  65 (defvar gnus-registry-dirty t
  66  "Boolean set to t when the registry is modified")
  67
  68 (defgroup gnus-registry nil
  69   "The Gnus registry."
  70   :version "22.1"
  71   :group 'gnus)
  72
  73 (defvar gnus-registry-hashtb nil
  74   "*The article registry by Message ID.")
  75
  76 (defcustom gnus-registry-unfollowed-groups '("delayed" "drafts" "queue")
  77   "List of groups that gnus-registry-split-fancy-with-parent won't follow.
  78 The group names are matched, they don't have to be fully qualified."
  79   :group 'gnus-registry
  80   :type '(repeat string))
  81
  82 (defcustom gnus-registry-install nil
  83   "Whether the registry should be installed."
  84   :group 'gnus-registry
  85   :type 'boolean)
  86
  87 (defcustom gnus-registry-clean-empty t
  88   "Whether the empty registry entries should be deleted.
  89 Registry entries are considered empty when they have no groups."
  90   :group 'gnus-registry
  91   :type 'boolean)
  92
  93 (defcustom gnus-registry-use-long-group-names nil
  94   "Whether the registry should use long group names (BUGGY)."
  95   :group 'gnus-registry
  96   :type 'boolean)
  97
  98 (defcustom gnus-registry-track-extra nil
  99   "Whether the registry should track extra data about a message.
 100 The Subject and Sender (From:) headers are currently tracked this
 101 way."
 102   :group 'gnus-registry
 103   :type
 104   '(set :tag "Tracking choices"
 105     (const :tag "Track by subject (Subject: header)" subject)
 106     (const :tag "Track by sender (From: header)"  sender)))
 107
 108 (defcustom gnus-registry-entry-caching t
 109   "Whether the registry should cache extra information."
 110   :group 'gnus-registry
 111   :type 'boolean)
 112
 113 (defcustom gnus-registry-minimum-subject-length 5
 114   "The minimum length of a subject before it's considered trackable."
 115   :group 'gnus-registry
 116   :type 'integer)
 117
 118 (defcustom gnus-registry-trim-articles-without-groups t
 119   "Whether the registry should clean out message IDs without groups."
 120   :group 'gnus-registry
 121   :type 'boolean)
 122
 123 (defcustom gnus-registry-cache-file "~/.gnus.registry.eld"
 124   "File where the Gnus registry will be stored."
 125   :group 'gnus-registry
 126   :type 'file)
 127
 128 (defcustom gnus-registry-max-entries nil
 129   "Maximum number of entries in the registry, nil for unlimited."
 130   :group 'gnus-registry
 131   :type '(radio (const :format "Unlimited " nil)
 132                 (integer :format "Maximum number: %v")))
 133
 134 ;; Function(s) missing in Emacs 20
 135 (when (memq nil (mapcar 'fboundp '(puthash)))
 136   (require 'cl)
 137   (unless (fboundp 'puthash)
 138     ;; alias puthash is missing from Emacs 20 cl-extra.el
 139     (defalias 'puthash 'cl-puthash)))
 140
 141 (defun gnus-registry-track-subject-p ()
 142   (memq 'subject gnus-registry-track-extra))
 143
 144 (defun gnus-registry-track-sender-p ()
 145   (memq 'sender gnus-registry-track-extra))
 146
 147 (defun gnus-registry-cache-read ()
 148   "Read the registry cache file."
 149   (interactive)
 150   (let ((file gnus-registry-cache-file))
 151     (when (file-exists-p file)
 152       (gnus-message 5 "Reading %s..." file)
 153       (gnus-load file)
 154       (gnus-message 5 "Reading %s...done" file))))
 155
 156 (defun gnus-registry-cache-save ()
 157   "Save the registry cache file."
 158   (interactive)
 159   (let ((file gnus-registry-cache-file))
 160     (save-excursion
 161       (set-buffer (gnus-get-buffer-create " *Gnus-registry-cache*"))
 162       (make-local-variable 'version-control)
 163     (setq version-control gnus-backup-startup-file)
 164     (setq buffer-file-name file)
 165     (setq default-directory (file-name-directory buffer-file-name))
 166     (buffer-disable-undo)
 167     (erase-buffer)
 168     (gnus-message 5 "Saving %s..." file)
 169     (if gnus-save-startup-file-via-temp-buffer
 170         (let ((coding-system-for-write gnus-ding-file-coding-system)
 171               (standard-output (current-buffer)))
 172           (gnus-gnus-to-quick-newsrc-format t "gnus registry startup file" 'gnus-registry-alist)
 173           (gnus-registry-cache-whitespace file)
 174           (save-buffer))
 175       (let ((coding-system-for-write gnus-ding-file-coding-system)
 176             (version-control gnus-backup-startup-file)
 177             (startup-file file)
 178             (working-dir (file-name-directory file))
 179             working-file
 180             (i -1))
 181         ;; Generate the name of a non-existent file.
 182         (while (progn (setq working-file
 183                             (format
 184                              (if (and (eq system-type 'ms-dos)
 185                                       (not (gnus-long-file-names)))
 186                                  "%s#%d.tm#" ; MSDOS limits files to 8+3
 187                                (if (memq system-type '(vax-vms axp-vms))
 188                                    "%s$tmp$%d"
 189                                  "%s#tmp#%d"))
 190                              working-dir (setq i (1+ i))))
 191                       (file-exists-p working-file)))
 192
 193         (unwind-protect
 194             (progn
 195               (gnus-with-output-to-file working-file
 196                 (gnus-gnus-to-quick-newsrc-format t "gnus registry startup file" 'gnus-registry-alist))
 197
 198               ;; These bindings will mislead the current buffer
 199               ;; into thinking that it is visiting the startup
 200               ;; file.
 201               (let ((buffer-backed-up nil)
 202                     (buffer-file-name startup-file)
 203                     (file-precious-flag t)
 204                     (setmodes (file-modes startup-file)))
 205                 ;; Backup the current version of the startup file.
 206                 (backup-buffer)
 207
 208                 ;; Replace the existing startup file with the temp file.
 209                 (rename-file working-file startup-file t)
 210                 (set-file-modes startup-file setmodes)))
 211           (condition-case nil
 212               (delete-file working-file)
 213             (file-error nil)))))
 214
 215     (gnus-kill-buffer (current-buffer))
 216     (gnus-message 5 "Saving %s...done" file))))
 217
 218 ;; Idea from Dan Christensen <jdc@chow.mat.jhu.edu>
 219 ;; Save the gnus-registry file with extra line breaks.
 220 (defun gnus-registry-cache-whitespace (filename)
 221   (gnus-message 5 "Adding whitespace to %s" filename)
 222   (save-excursion
 223     (goto-char (point-min))
 224     (while (re-search-forward "^(\\|(\\\"" nil t)
 225       (replace-match "\n\\&" t))
 226     (goto-char (point-min))
 227     (while (re-search-forward " $" nil t)
 228       (replace-match "" t t))))
 229
 230 (defun gnus-registry-save (&optional force)
 231   (when (or gnus-registry-dirty force)
 232     (let ((caching gnus-registry-entry-caching))
 233       ;; turn off entry caching, so mtime doesn't get recorded
 234       (setq gnus-registry-entry-caching nil)
 235       ;; remove entry caches
 236       (maphash
 237        (lambda (key value)
 238          (if (hash-table-p value)
 239              (remhash key gnus-registry-hashtb)))
 240        gnus-registry-hashtb)
 241       ;; remove empty entries
 242       (when gnus-registry-clean-empty
 243         (gnus-registry-clean-empty-function))
 244       ;; now trim the registry appropriately
 245       (setq gnus-registry-alist (gnus-registry-trim
 246                                  (hashtable-to-alist gnus-registry-hashtb)))
 247       ;; really save
 248       (gnus-registry-cache-save)
 249       (setq gnus-registry-entry-caching caching)
 250       (setq gnus-registry-dirty nil))))
 251
 252 (defun gnus-registry-clean-empty-function ()
 253   "Remove all empty entries from the registry.  Returns count thereof."
 254   (let ((count 0))
 255     (maphash
 256      (lambda (key value)
 257        (unless (gnus-registry-fetch-group key)
 258          (incf count)
 259          (remhash key gnus-registry-hashtb)))
 260      gnus-registry-hashtb)
 261     count))
 262
 263 (defun gnus-registry-read ()
 264   (gnus-registry-cache-read)
 265   (setq gnus-registry-hashtb (alist-to-hashtable gnus-registry-alist))
 266   (setq gnus-registry-dirty nil))
 267
 268 (defun gnus-registry-trim (alist)
 269   "Trim alist to size, using gnus-registry-max-entries."
 270   (if (null gnus-registry-max-entries)
 271       alist                             ; just return the alist
 272     ;; else, when given max-entries, trim the alist
 273     (let* ((timehash (make-hash-table
 274                       :size 4096
 275                       :test 'equal))
 276            (trim-length (- (length alist) gnus-registry-max-entries))
 277            (trim-length (if (natnump trim-length) trim-length 0)))
 278       (maphash
 279        (lambda (key value)
 280          (puthash key (gnus-registry-fetch-extra key 'mtime) timehash))
 281        gnus-registry-hashtb)
 282
 283       ;; we use the return value of this setq, which is the trimmed alist
 284       (setq alist
 285             (nthcdr
 286              trim-length
 287              (sort alist
 288                    (lambda (a b)
 289                      (time-less-p
 290                       (cdr (gethash (car a) timehash))
 291                       (cdr (gethash (car b) timehash))))))))))
 292
 293 (defun alist-to-hashtable (alist)
 294   "Build a hashtable from the values in ALIST."
 295   (let ((ht (make-hash-table
 296              :size 4096
 297              :test 'equal)))
 298     (mapc
 299      (lambda (kv-pair)
 300        (puthash (car kv-pair) (cdr kv-pair) ht))
 301      alist)
 302      ht))
 303
 304 (defun hashtable-to-alist (hash)
 305   "Build an alist from the values in HASH."
 306   (let ((list nil))
 307     (maphash
 308      (lambda (key value)
 309        (setq list (cons (cons key value) list)))
 310      hash)
 311     list))
 312
 313 (defun gnus-registry-action (action data-header from &optional to method)
 314   (let* ((id (mail-header-id data-header))
 315          (subject (gnus-registry-simplify-subject
 316                    (mail-header-subject data-header)))
 317          (sender (mail-header-from data-header))
 318          (from (gnus-group-guess-full-name-from-command-method from))
 319          (to (if to (gnus-group-guess-full-name-from-command-method to) nil))
 320          (to-name (if to to "the Bit Bucket"))
 321          (old-entry (gethash id gnus-registry-hashtb)))
 322     (gnus-message 5 "Registry: article %s %s from %s to %s"
 323                   id
 324                   (if method "respooling" "going")
 325                   from
 326                   to)
 327
 328     ;; All except copy will need a delete
 329     (gnus-registry-delete-group id from)
 330
 331     (when (equal 'copy action)
 332       (gnus-registry-add-group id from subject sender)) ; undo the delete
 333
 334     (gnus-registry-add-group id to subject sender)))
 335
 336 (defun gnus-registry-spool-action (id group &optional subject sender)
 337   (let ((group (gnus-group-guess-full-name-from-command-method group)))
 338     (when (and (stringp id) (string-match "\r$" id))
 339       (setq id (substring id 0 -1)))
 340     (gnus-message 5 "Registry: article %s spooled to %s"
 341                   id
 342                   group)
 343     (gnus-registry-add-group id group subject sender)))
 344
 345 ;; Function for nn{mail|imap}-split-fancy: look up all references in
 346 ;; the cache and if a match is found, return that group.
 347 (defun gnus-registry-split-fancy-with-parent ()
 348   "Split this message into the same group as its parent.  The parent
 349 is obtained from the registry.  This function can be used as an entry
 350 in `nnmail-split-fancy' or `nnimap-split-fancy', for example like
 351 this: (: gnus-registry-split-fancy-with-parent)
 352
 353 For a message to be split, it looks for the parent message in the
 354 References or In-Reply-To header and then looks in the registry to
 355 see which group that message was put in.  This group is returned.
 356
 357 See the Info node `(gnus)Fancy Mail Splitting' for more details."
 358   (let ((refstr (or (message-fetch-field "references")
 359                     (message-fetch-field "in-reply-to")))
 360         (nnmail-split-fancy-with-parent-ignore-groups
 361          (if (listp nnmail-split-fancy-with-parent-ignore-groups)
 362              nnmail-split-fancy-with-parent-ignore-groups
 363            (list nnmail-split-fancy-with-parent-ignore-groups)))
 364         references res)
 365     (if refstr
 366         (progn
 367           (setq references (nreverse (gnus-split-references refstr)))
 368           (mapcar (lambda (x)
 369                     (setq res (or (gnus-registry-fetch-group x) res))
 370                     (when (or (gnus-registry-grep-in-list
 371                                res
 372                                gnus-registry-unfollowed-groups)
 373                               (gnus-registry-grep-in-list
 374                                res
 375                                nnmail-split-fancy-with-parent-ignore-groups))
 376                       (setq res nil)))
 377                   references))
 378
 379       ;; else: there were no references, now try the extra tracking
 380       (let ((sender (message-fetch-field "from"))
 381             (subject (gnus-registry-simplify-subject
 382                       (message-fetch-field "subject")))
 383             (single-match t))
 384         (when (and single-match
 385                    (gnus-registry-track-sender-p)
 386                    sender)
 387           (maphash
 388            (lambda (key value)
 389              (let ((this-sender (cdr
 390                                  (gnus-registry-fetch-extra key 'sender))))
 391                (when (and single-match
 392                           this-sender
 393                           (equal sender this-sender))
 394                  ;; too many matches, bail
 395                  (unless (equal res (gnus-registry-fetch-group key))
 396                    (setq single-match nil))
 397                  (setq res (gnus-registry-fetch-group key))
 398                  (gnus-message
 399                   ;; raise level of messaging if gnus-registry-track-extra
 400                   (if gnus-registry-track-extra 5 9)
 401                   "%s (extra tracking) traced sender %s to group %s"
 402                   "gnus-registry-split-fancy-with-parent"
 403                   sender
 404                   (if res res "nil")))))
 405            gnus-registry-hashtb))
 406         (when (and single-match
 407                    (gnus-registry-track-subject-p)
 408                    subject
 409                    (< gnus-registry-minimum-subject-length (length subject)))
 410           (maphash
 411            (lambda (key value)
 412              (let ((this-subject (cdr
 413                                   (gnus-registry-fetch-extra key 'subject))))
 414                (when (and single-match
 415                           this-subject
 416                           (equal subject this-subject))
 417                  ;; too many matches, bail
 418                  (unless (equal res (gnus-registry-fetch-group key))
 419                    (setq single-match nil))
 420                  (setq res (gnus-registry-fetch-group key))
 421                  (gnus-message
 422                   ;; raise level of messaging if gnus-registry-track-extra
 423                   (if gnus-registry-track-extra 5 9)
 424                   "%s (extra tracking) traced subject %s to group %s"
 425                   "gnus-registry-split-fancy-with-parent"
 426                   subject
 427                   (if res res "nil")))))
 428            gnus-registry-hashtb))
 429         (unless single-match
 430           (gnus-message
 431            5
 432            "gnus-registry-split-fancy-with-parent: too many extra matches for %s"
 433            refstr)
 434           (setq res nil))))
 435     (gnus-message
 436      5
 437      "gnus-registry-split-fancy-with-parent traced %s to group %s"
 438      refstr (if res res "nil"))
 439
 440     (when (and res gnus-registry-use-long-group-names)
 441       (let ((m1 (gnus-find-method-for-group res))
 442             (m2 (or gnus-command-method
 443                     (gnus-find-method-for-group gnus-newsgroup-name)))
 444             (short-res (gnus-group-short-name res)))
 445       (if (gnus-methods-equal-p m1 m2)
 446           (progn
 447             (gnus-message
 448              9
 449              "gnus-registry-split-fancy-with-parent stripped group %s to %s"
 450              res
 451              short-res)
 452             (setq res short-res))
 453         ;; else...
 454         (gnus-message
 455          5
 456          "gnus-registry-split-fancy-with-parent ignored foreign group %s"
 457          res)
 458         (setq res nil))))
 459     res))
 460
 461 (defun gnus-registry-register-message-ids ()
 462   "Register the Message-ID of every article in the group"
 463   (unless (gnus-parameter-registry-ignore gnus-newsgroup-name)
 464     (dolist (article gnus-newsgroup-articles)
 465       (let ((id (gnus-registry-fetch-message-id-fast article)))
 466         (unless (gnus-registry-fetch-group id)
 467           (gnus-message 9 "Registry: Registering article %d with group %s"
 468                         article gnus-newsgroup-name)
 469           (gnus-registry-add-group
 470            (gnus-registry-fetch-message-id-fast article)
 471            gnus-newsgroup-name
 472            (gnus-registry-fetch-simplified-message-subject-fast article)
 473            (gnus-registry-fetch-sender-fast article)))))))
 474
 475 (defun gnus-registry-fetch-message-id-fast (article)
 476   "Fetch the Message-ID quickly, using the internal gnus-data-list function"
 477   (if (and (numberp article)
 478            (assoc article (gnus-data-list nil)))
 479       (mail-header-id (gnus-data-header (assoc article (gnus-data-list nil))))
 480     nil))
 481
 482 (defun gnus-registry-simplify-subject (subject)
 483   (if (stringp subject)
 484       (gnus-simplify-subject subject)
 485     nil))
 486
 487 (defun gnus-registry-fetch-simplified-message-subject-fast (article)
 488   "Fetch the Subject quickly, using the internal gnus-data-list function"
 489   (if (and (numberp article)
 490            (assoc article (gnus-data-list nil)))
 491       (gnus-registry-simplify-subject
 492        (mail-header-subject (gnus-data-header
 493                              (assoc article (gnus-data-list nil)))))
 494     nil))
 495
 496 (defun gnus-registry-fetch-sender-fast (article)
 497   "Fetch the Sender quickly, using the internal gnus-data-list function"
 498   (if (and (numberp article)
 499            (assoc article (gnus-data-list nil)))
 500       (mail-header-from (gnus-data-header
 501                          (assoc article (gnus-data-list nil))))
 502     nil))
 503
 504 (defun gnus-registry-grep-in-list (word list)
 505   (when word
 506     (memq nil
 507           (mapcar 'not
 508                   (mapcar
 509                    (lambda (x)
 510                      (string-match x word))
 511                    list)))))
 512
 513 (defun gnus-registry-fetch-extra (id &optional entry)
 514   "Get the extra data of a message, based on the message ID.
 515 Returns the first place where the trail finds a nonstring."
 516   (let ((entry-cache (gethash entry gnus-registry-hashtb)))
 517     (if (and entry
 518              (hash-table-p entry-cache)
 519              (gethash id entry-cache))
 520         (gethash id entry-cache)
 521       ;; else, if there is no caching possible...
 522       (let ((trail (gethash id gnus-registry-hashtb)))
 523         (when (listp trail)
 524           (dolist (crumb trail)
 525             (unless (stringp crumb)
 526               (return (gnus-registry-fetch-extra-entry crumb entry id)))))))))
 527
 528 (defun gnus-registry-fetch-extra-entry (alist &optional entry id)
 529   "Get the extra data of a message, or a specific entry in it.
 530 Update the entry cache if needed."
 531   (if (and entry id)
 532       (let ((entry-cache (gethash entry gnus-registry-hashtb))
 533             entree)
 534         (when gnus-registry-entry-caching
 535           ;; create the hash table
 536           (unless (hash-table-p entry-cache)
 537             (setq entry-cache (make-hash-table
 538                                :size 4096
 539                                :test 'equal))
 540             (puthash entry entry-cache gnus-registry-hashtb))
 541
 542           ;; get the entree from the hash table or from the alist
 543           (setq entree (gethash id entry-cache)))
 544
 545         (unless entree
 546           (setq entree (assq entry alist))
 547           (when gnus-registry-entry-caching
 548             (puthash id entree entry-cache)))
 549         entree)
 550     alist))
 551
 552 (defun gnus-registry-store-extra (id extra)
 553   "Store the extra data of a message, based on the message ID.
 554 The message must have at least one group name."
 555   (when (gnus-registry-group-count id)
 556     ;; we now know the trail has at least 1 group name, so it's not empty
 557     (let ((trail (gethash id gnus-registry-hashtb))
 558           (old-extra (gnus-registry-fetch-extra id))
 559           entry-cache)
 560       (dolist (crumb trail)
 561         (unless (stringp crumb)
 562           (dolist (entry crumb)
 563             (setq entry-cache (gethash (car entry) gnus-registry-hashtb))
 564           (when entry-cache
 565             (remhash id entry-cache))))
 566       (puthash id (cons extra (delete old-extra trail))
 567                gnus-registry-hashtb)
 568       (setq gnus-registry-dirty t)))))
 569
 570 (defun gnus-registry-store-extra-entry (id key value)
 571   "Put a specific entry in the extras field of the registry entry for id."
 572   (let* ((extra (gnus-registry-fetch-extra id))
 573          (alist (cons (cons key value)
 574                  (gnus-assq-delete-all key (gnus-registry-fetch-extra id)))))
 575     (gnus-registry-store-extra id alist)))
 576
 577 (defun gnus-registry-fetch-group (id)
 578   "Get the group of a message, based on the message ID.
 579 Returns the first place where the trail finds a group name."
 580   (when (gnus-registry-group-count id)
 581     ;; we now know the trail has at least 1 group name
 582     (let ((trail (gethash id gnus-registry-hashtb)))
 583       (dolist (crumb trail)
 584         (when (stringp crumb)
 585           (return (if gnus-registry-use-long-group-names
 586                        crumb
 587                      (gnus-group-short-name crumb))))))))
 588
 589 (defun gnus-registry-group-count (id)
 590   "Get the number of groups of a message, based on the message ID."
 591   (let ((trail (gethash id gnus-registry-hashtb)))
 592     (if (and trail (listp trail))
 593         (apply '+ (mapcar (lambda (x) (if (stringp x) 1 0)) trail))
 594       0)))
 595
 596 (defun gnus-registry-delete-group (id group)
 597   "Delete a group for a message, based on the message ID."
 598   (when group
 599     (when id
 600       (let ((trail (gethash id gnus-registry-hashtb))
 601             (group (gnus-group-short-name group)))
 602         (puthash id (if trail
 603                         (delete group trail)
 604                       nil)
 605                  gnus-registry-hashtb))
 606       ;; now, clear the entry if there are no more groups
 607       (when gnus-registry-trim-articles-without-groups
 608         (unless (gnus-registry-group-count id)
 609           (gnus-registry-delete-id id)))
 610       ;; is this ID still in the registry?
 611       (when (gethash id gnus-registry-hashtb)
 612         (gnus-registry-store-extra-entry id 'mtime (current-time))))))
 613
 614 (defun gnus-registry-delete-id (id)
 615   "Delete a message ID from the registry."
 616   (when (stringp id)
 617     (remhash id gnus-registry-hashtb)
 618     (maphash
 619      (lambda (key value)
 620        (when (hash-table-p value)
 621          (remhash id value)))
 622      gnus-registry-hashtb)))
 623
 624 (defun gnus-registry-add-group (id group &optional subject sender)
 625   "Add a group for a message, based on the message ID."
 626   (when group
 627     (when (and id
 628                (not (string-match "totally-fudged-out-message-id" id)))
 629       (let ((full-group group)
 630             (group (if gnus-registry-use-long-group-names
 631                        group
 632                      (gnus-group-short-name group))))
 633         (gnus-registry-delete-group id group)
 634
 635         (unless gnus-registry-use-long-group-names ;; unnecessary in this case
 636           (gnus-registry-delete-group id full-group))
 637
 638         (let ((trail (gethash id gnus-registry-hashtb)))
 639           (puthash id (if trail
 640                           (cons group trail)
 641                         (list group))
 642                    gnus-registry-hashtb)
 643
 644           (when (and (gnus-registry-track-subject-p)
 645                      subject)
 646             (gnus-registry-store-extra-entry
 647              id
 648              'subject
 649              (gnus-registry-simplify-subject subject)))
 650           (when (and (gnus-registry-track-sender-p)
 651                      sender)
 652             (gnus-registry-store-extra-entry
 653              id
 654              'sender
 655              sender))
 656
 657           (gnus-registry-store-extra-entry id 'mtime (current-time)))))))
 658
 659 (defun gnus-registry-clear ()
 660   "Clear the Gnus registry."
 661   (interactive)
 662   (setq gnus-registry-alist nil)
 663   (setq gnus-registry-hashtb (alist-to-hashtable gnus-registry-alist))
 664   (setq gnus-registry-dirty t))
 665
 666 ;;;###autoload
 667 (defun gnus-registry-initialize ()
 668   (interactive)
 669   (setq gnus-registry-install t)
 670   (gnus-registry-install-hooks)
 671   (gnus-registry-read))
 672
 673 ;;;###autoload
 674 (defun gnus-registry-install-hooks ()
 675   "Install the registry hooks."
 676   (interactive)
 677   (add-hook 'gnus-summary-article-move-hook 'gnus-registry-action)
 678   (add-hook 'gnus-summary-article-delete-hook 'gnus-registry-action)
 679   (add-hook 'gnus-summary-article-expire-hook 'gnus-registry-action)
 680   (add-hook 'nnmail-spool-hook 'gnus-registry-spool-action)
 681
 682   (add-hook 'gnus-save-newsrc-hook 'gnus-registry-save)
 683   (add-hook 'gnus-read-newsrc-el-hook 'gnus-registry-read)
 684
 685   (add-hook 'gnus-summary-prepare-hook 'gnus-registry-register-message-ids))
 686
 687 (defun gnus-registry-unload-hook ()
 688   "Uninstall the registry hooks."
 689   (interactive)
 690   (remove-hook 'gnus-summary-article-move-hook 'gnus-registry-action)
 691   (remove-hook 'gnus-summary-article-delete-hook 'gnus-registry-action)
 692   (remove-hook 'gnus-summary-article-expire-hook 'gnus-registry-action)
 693   (remove-hook 'nnmail-spool-hook 'gnus-registry-spool-action)
 694
 695   (remove-hook 'gnus-save-newsrc-hook 'gnus-registry-save)
 696   (remove-hook 'gnus-read-newsrc-el-hook 'gnus-registry-read)
 697
 698   (remove-hook 'gnus-summary-prepare-hook 'gnus-registry-register-message-ids))
 699
 700 (add-hook 'gnus-registry-unload-hook 'gnus-registry-unload-hook)
 701
 702 (when gnus-registry-install
 703   (gnus-registry-install-hooks)
 704   (gnus-registry-read))
 705
 706 ;; TODO: a lot of things
 707
 708 (provide 'gnus-registry)
 709
 710 ;;; arch-tag: 5cba0a32-718a-4a97-8c91-0a15af21da94
 711 ;;; gnus-registry.el ends here