lisp/gnus/gnus-registry.el

   1 ;;; gnus-registry.el --- article registry for Gnus
   2 ;; Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004
   3 ;;        Free Software Foundation, Inc.
   4
   5 ;; Author: Ted Zlatanov <tzz@lifelogs.com>
   6 ;; Keywords: news
   7
   8 ;; This file is part of GNU Emacs.
   9
  10 ;; GNU Emacs is free software; you can redistribute it and/or modify
  11 ;; it under the terms of the GNU General Public License as published by
  12 ;; the Free Software Foundation; either version 2, or (at your option)
  13 ;; any later version.
  14
  15 ;; GNU Emacs is distributed in the hope that it will be useful,
  16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ;; GNU General Public License for more details.
  19
  20 ;; You should have received a copy of the GNU General Public License
  21 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  22 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  23 ;; Boston, MA 02111-1307, USA.
  24
  25 ;;; Commentary:
  26
  27 ;; This is the gnus-registry.el package, works with other backends
  28 ;; besides nnmail.  The major issue is that it doesn't go across
  29 ;; backends, so for instance if an article is in nnml:sys and you see
  30 ;; a reference to it in nnimap splitting, the article will end up in
  31 ;; nnimap:sys
  32
  33 ;; gnus-registry.el intercepts article respooling, moving, deleting,
  34 ;; and copying for all backends.  If it doesn't work correctly for
  35 ;; you, submit a bug report and I'll be glad to fix it.  It needs
  36 ;; documentation in the manual (also on my to-do list).
  37
  38 ;; Put this in your startup file (~/.gnus.el for instance)
  39
  40 ;; (setq gnus-registry-max-entries 2500
  41 ;;       gnus-registry-use-long-group-names t)
  42
  43 ;; (gnus-registry-initialize)
  44
  45 ;; Then use this in your fancy-split:
  46
  47 ;; (: gnus-registry-split-fancy-with-parent)
  48
  49 ;; TODO:
  50
  51 ;; - get the correct group on spool actions
  52
  53 ;; - articles that are spooled to a different backend should be handled
  54
  55 ;;; Code:
  56
  57 (eval-when-compile (require 'cl))
  58
  59 (require 'gnus)
  60 (require 'gnus-int)
  61 (require 'gnus-sum)
  62 (require 'nnmail)
  63
  64 (defvar gnus-registry-dirty t
  65  "Boolean set to t when the registry is modified")
  66
  67 (defgroup gnus-registry nil
  68   "The Gnus registry."
  69   :version "22.1"
  70   :group 'gnus)
  71
  72 (defvar gnus-registry-hashtb nil
  73   "*The article registry by Message ID.")
  74
  75 (defcustom gnus-registry-unfollowed-groups '("delayed" "drafts" "queue")
  76   "List of groups that gnus-registry-split-fancy-with-parent won't follow.
  77 The group names are matched, they don't have to be fully qualified."
  78   :group 'gnus-registry
  79   :type '(repeat string))
  80
  81 (defcustom gnus-registry-install nil
  82   "Whether the registry should be installed."
  83   :group 'gnus-registry
  84   :type 'boolean)
  85
  86 (defcustom gnus-registry-clean-empty t
  87   "Whether the empty registry entries should be deleted.
  88 Registry entries are considered empty when they have no groups."
  89   :group 'gnus-registry
  90   :type 'boolean)
  91
  92 (defcustom gnus-registry-use-long-group-names nil
  93   "Whether the registry should use long group names (BUGGY)."
  94   :group 'gnus-registry
  95   :type 'boolean)
  96
  97 (defcustom gnus-registry-track-extra nil
  98   "Whether the registry should track extra data about a message.
  99 The Subject and Sender (From:) headers are currently tracked this
 100 way."
 101   :group 'gnus-registry
 102   :type
 103   '(set :tag "Tracking choices"
 104     (const :tag "Track by subject (Subject: header)" subject)
 105     (const :tag "Track by sender (From: header)"  sender)))
 106
 107 (defcustom gnus-registry-entry-caching t
 108   "Whether the registry should cache extra information."
 109   :group 'gnus-registry
 110   :type 'boolean)
 111
 112 (defcustom gnus-registry-minimum-subject-length 5
 113   "The minimum length of a subject before it's considered trackable."
 114   :group 'gnus-registry
 115   :type 'integer)
 116
 117 (defcustom gnus-registry-trim-articles-without-groups t
 118   "Whether the registry should clean out message IDs without groups."
 119   :group 'gnus-registry
 120   :type 'boolean)
 121
 122 (defcustom gnus-registry-cache-file "~/.gnus.registry.eld"
 123   "File where the Gnus registry will be stored."
 124   :group 'gnus-registry
 125   :type 'file)
 126
 127 (defcustom gnus-registry-max-entries nil
 128   "Maximum number of entries in the registry, nil for unlimited."
 129   :group 'gnus-registry
 130   :type '(radio (const :format "Unlimited " nil)
 131                 (integer :format "Maximum number: %v")))
 132
 133 ;; Function(s) missing in Emacs 20
 134 (when (memq nil (mapcar 'fboundp '(puthash)))
 135   (require 'cl)
 136   (unless (fboundp 'puthash)
 137     ;; alias puthash is missing from Emacs 20 cl-extra.el
 138     (defalias 'puthash 'cl-puthash)))
 139
 140 (defun gnus-registry-track-subject-p ()
 141   (memq 'subject gnus-registry-track-extra))
 142
 143 (defun gnus-registry-track-sender-p ()
 144   (memq 'sender gnus-registry-track-extra))
 145
 146 (defun gnus-registry-cache-read ()
 147   "Read the registry cache file."
 148   (interactive)
 149   (let ((file gnus-registry-cache-file))
 150     (when (file-exists-p file)
 151       (gnus-message 5 "Reading %s..." file)
 152       (gnus-load file)
 153       (gnus-message 5 "Reading %s...done" file))))
 154
 155 (defun gnus-registry-cache-save ()
 156   "Save the registry cache file."
 157   (interactive)
 158   (let ((file gnus-registry-cache-file))
 159     (save-excursion
 160       (set-buffer (gnus-get-buffer-create " *Gnus-registry-cache*"))
 161       (make-local-variable 'version-control)
 162     (setq version-control gnus-backup-startup-file)
 163     (setq buffer-file-name file)
 164     (setq default-directory (file-name-directory buffer-file-name))
 165     (buffer-disable-undo)
 166     (erase-buffer)
 167     (gnus-message 5 "Saving %s..." file)
 168     (if gnus-save-startup-file-via-temp-buffer
 169         (let ((coding-system-for-write gnus-ding-file-coding-system)
 170               (standard-output (current-buffer)))
 171           (gnus-gnus-to-quick-newsrc-format t "gnus registry startup file" 'gnus-registry-alist)
 172           (gnus-registry-cache-whitespace file)
 173           (save-buffer))
 174       (let ((coding-system-for-write gnus-ding-file-coding-system)
 175             (version-control gnus-backup-startup-file)
 176             (startup-file file)
 177             (working-dir (file-name-directory file))
 178             working-file
 179             (i -1))
 180         ;; Generate the name of a non-existent file.
 181         (while (progn (setq working-file
 182                             (format
 183                              (if (and (eq system-type 'ms-dos)
 184                                       (not (gnus-long-file-names)))
 185                                  "%s#%d.tm#" ; MSDOS limits files to 8+3
 186                                (if (memq system-type '(vax-vms axp-vms))
 187                                    "%s$tmp$%d"
 188                                  "%s#tmp#%d"))
 189                              working-dir (setq i (1+ i))))
 190                       (file-exists-p working-file)))
 191
 192         (unwind-protect
 193             (progn
 194               (gnus-with-output-to-file working-file
 195                 (gnus-gnus-to-quick-newsrc-format t "gnus registry startup file" 'gnus-registry-alist))
 196
 197               ;; These bindings will mislead the current buffer
 198               ;; into thinking that it is visiting the startup
 199               ;; file.
 200               (let ((buffer-backed-up nil)
 201                     (buffer-file-name startup-file)
 202                     (file-precious-flag t)
 203                     (setmodes (file-modes startup-file)))
 204                 ;; Backup the current version of the startup file.
 205                 (backup-buffer)
 206
 207                 ;; Replace the existing startup file with the temp file.
 208                 (rename-file working-file startup-file t)
 209                 (set-file-modes startup-file setmodes)))
 210           (condition-case nil
 211               (delete-file working-file)
 212             (file-error nil)))))
 213
 214     (gnus-kill-buffer (current-buffer))
 215     (gnus-message 5 "Saving %s...done" file))))
 216
 217 ;; Idea from Dan Christensen <jdc@chow.mat.jhu.edu>
 218 ;; Save the gnus-registry file with extra line breaks.
 219 (defun gnus-registry-cache-whitespace (filename)
 220   (gnus-message 5 "Adding whitespace to %s" filename)
 221   (save-excursion
 222     (goto-char (point-min))
 223     (while (re-search-forward "^(\\|(\\\"" nil t)
 224       (replace-match "\n\\&" t))
 225     (goto-char (point-min))
 226     (while (re-search-forward " $" nil t)
 227       (replace-match "" t t))))
 228
 229 (defun gnus-registry-save (&optional force)
 230   (when (or gnus-registry-dirty force)
 231     (let ((caching gnus-registry-entry-caching))
 232       ;; turn off entry caching, so mtime doesn't get recorded
 233       (setq gnus-registry-entry-caching nil)
 234       ;; remove entry caches
 235       (maphash
 236        (lambda (key value)
 237          (if (hash-table-p value)
 238              (remhash key gnus-registry-hashtb)))
 239        gnus-registry-hashtb)
 240       ;; remove empty entries
 241       (when gnus-registry-clean-empty
 242         (gnus-registry-clean-empty-function))
 243       ;; now trim the registry appropriately
 244       (setq gnus-registry-alist (gnus-registry-trim
 245                                  (hashtable-to-alist gnus-registry-hashtb)))
 246       ;; really save
 247       (gnus-registry-cache-save)
 248       (setq gnus-registry-entry-caching caching)
 249       (setq gnus-registry-dirty nil))))
 250
 251 (defun gnus-registry-clean-empty-function ()
 252   "Remove all empty entries from the registry.  Returns count thereof."
 253   (let ((count 0))
 254     (maphash
 255      (lambda (key value)
 256        (unless (gnus-registry-fetch-group key)
 257          (incf count)
 258          (remhash key gnus-registry-hashtb)))
 259      gnus-registry-hashtb)
 260     count))
 261
 262 (defun gnus-registry-read ()
 263   (gnus-registry-cache-read)
 264   (setq gnus-registry-hashtb (alist-to-hashtable gnus-registry-alist))
 265   (setq gnus-registry-dirty nil))
 266
 267 (defun gnus-registry-trim (alist)
 268   "Trim alist to size, using gnus-registry-max-entries."
 269   (if (null gnus-registry-max-entries)
 270       alist                             ; just return the alist
 271     ;; else, when given max-entries, trim the alist
 272     (let* ((timehash (make-hash-table
 273                       :size 4096
 274                       :test 'equal))
 275            (trim-length (- (length alist) gnus-registry-max-entries))
 276            (trim-length (if (natnump trim-length) trim-length 0)))
 277       (maphash
 278        (lambda (key value)
 279          (puthash key (gnus-registry-fetch-extra key 'mtime) timehash))
 280        gnus-registry-hashtb)
 281
 282       ;; we use the return value of this setq, which is the trimmed alist
 283       (setq alist
 284             (nthcdr
 285              trim-length
 286              (sort alist
 287                    (lambda (a b)
 288                      (time-less-p
 289                       (cdr (gethash (car a) timehash))
 290                       (cdr (gethash (car b) timehash))))))))))
 291
 292 (defun alist-to-hashtable (alist)
 293   "Build a hashtable from the values in ALIST."
 294   (let ((ht (make-hash-table
 295              :size 4096
 296              :test 'equal)))
 297     (mapc
 298      (lambda (kv-pair)
 299        (puthash (car kv-pair) (cdr kv-pair) ht))
 300      alist)
 301      ht))
 302
 303 (defun hashtable-to-alist (hash)
 304   "Build an alist from the values in HASH."
 305   (let ((list nil))
 306     (maphash
 307      (lambda (key value)
 308        (setq list (cons (cons key value) list)))
 309      hash)
 310     list))
 311
 312 (defun gnus-registry-action (action data-header from &optional to method)
 313   (let* ((id (mail-header-id data-header))
 314          (subject (gnus-registry-simplify-subject
 315                    (mail-header-subject data-header)))
 316          (sender (mail-header-from data-header))
 317          (from (gnus-group-guess-full-name-from-command-method from))
 318          (to (if to (gnus-group-guess-full-name-from-command-method to) nil))
 319          (to-name (if to to "the Bit Bucket"))
 320          (old-entry (gethash id gnus-registry-hashtb)))
 321     (gnus-message 5 "Registry: article %s %s from %s to %s"
 322                   id
 323                   (if method "respooling" "going")
 324                   from
 325                   to)
 326
 327     ;; All except copy will need a delete
 328     (gnus-registry-delete-group id from)
 329
 330     (when (equal 'copy action)
 331       (gnus-registry-add-group id from subject sender)) ; undo the delete
 332
 333     (gnus-registry-add-group id to subject sender)))
 334
 335 (defun gnus-registry-spool-action (id group &optional subject sender)
 336   (let ((group (gnus-group-guess-full-name-from-command-method group)))
 337     (when (and (stringp id) (string-match "\r$" id))
 338       (setq id (substring id 0 -1)))
 339     (gnus-message 5 "Registry: article %s spooled to %s"
 340                   id
 341                   group)
 342     (gnus-registry-add-group id group subject sender)))
 343
 344 ;; Function for nn{mail|imap}-split-fancy: look up all references in
 345 ;; the cache and if a match is found, return that group.
 346 (defun gnus-registry-split-fancy-with-parent ()
 347   "Split this message into the same group as its parent.  The parent
 348 is obtained from the registry.  This function can be used as an entry
 349 in `nnmail-split-fancy' or `nnimap-split-fancy', for example like
 350 this: (: gnus-registry-split-fancy-with-parent)
 351
 352 For a message to be split, it looks for the parent message in the
 353 References or In-Reply-To header and then looks in the registry to
 354 see which group that message was put in.  This group is returned.
 355
 356 See the Info node `(gnus)Fancy Mail Splitting' for more details."
 357   (let ((refstr (or (message-fetch-field "references")
 358                     (message-fetch-field "in-reply-to")))
 359         (nnmail-split-fancy-with-parent-ignore-groups
 360          (if (listp nnmail-split-fancy-with-parent-ignore-groups)
 361              nnmail-split-fancy-with-parent-ignore-groups
 362            (list nnmail-split-fancy-with-parent-ignore-groups)))
 363         references res)
 364     (if refstr
 365         (progn
 366           (setq references (nreverse (gnus-split-references refstr)))
 367           (mapcar (lambda (x)
 368                     (setq res (or (gnus-registry-fetch-group x) res))
 369                     (when (or (gnus-registry-grep-in-list
 370                                res
 371                                gnus-registry-unfollowed-groups)
 372                               (gnus-registry-grep-in-list
 373                                res
 374                                nnmail-split-fancy-with-parent-ignore-groups))
 375                       (setq res nil)))
 376                   references))
 377
 378       ;; else: there were no references, now try the extra tracking
 379       (let ((sender (message-fetch-field "from"))
 380             (subject (gnus-registry-simplify-subject
 381                       (message-fetch-field "subject")))
 382             (single-match t))
 383         (when (and single-match
 384                    (gnus-registry-track-sender-p)
 385                    sender)
 386           (maphash
 387            (lambda (key value)
 388              (let ((this-sender (cdr
 389                                  (gnus-registry-fetch-extra key 'sender))))
 390                (when (and single-match
 391                           this-sender
 392                           (equal sender this-sender))
 393                  ;; too many matches, bail
 394                  (unless (equal res (gnus-registry-fetch-group key))
 395                    (setq single-match nil))
 396                  (setq res (gnus-registry-fetch-group key))
 397                  (gnus-message
 398                   ;; raise level of messaging if gnus-registry-track-extra
 399                   (if gnus-registry-track-extra 5 9)
 400                   "%s (extra tracking) traced sender %s to group %s"
 401                   "gnus-registry-split-fancy-with-parent"
 402                   sender
 403                   (if res res "nil")))))
 404            gnus-registry-hashtb))
 405         (when (and single-match
 406                    (gnus-registry-track-subject-p)
 407                    subject
 408                    (< gnus-registry-minimum-subject-length (length subject)))
 409           (maphash
 410            (lambda (key value)
 411              (let ((this-subject (cdr
 412                                   (gnus-registry-fetch-extra key 'subject))))
 413                (when (and single-match
 414                           this-subject
 415                           (equal subject this-subject))
 416                  ;; too many matches, bail
 417                  (unless (equal res (gnus-registry-fetch-group key))
 418                    (setq single-match nil))
 419                  (setq res (gnus-registry-fetch-group key))
 420                  (gnus-message
 421                   ;; raise level of messaging if gnus-registry-track-extra
 422                   (if gnus-registry-track-extra 5 9)
 423                   "%s (extra tracking) traced subject %s to group %s"
 424                   "gnus-registry-split-fancy-with-parent"
 425                   subject
 426                   (if res res "nil")))))
 427            gnus-registry-hashtb))
 428         (unless single-match
 429           (gnus-message
 430            5
 431            "gnus-registry-split-fancy-with-parent: too many extra matches for %s"
 432            refstr)
 433           (setq res nil))))
 434     (gnus-message
 435      5
 436      "gnus-registry-split-fancy-with-parent traced %s to group %s"
 437      refstr (if res res "nil"))
 438
 439     (when (and res gnus-registry-use-long-group-names)
 440       (let ((m1 (gnus-find-method-for-group res))
 441             (m2 (or gnus-command-method
 442                     (gnus-find-method-for-group gnus-newsgroup-name)))
 443             (short-res (gnus-group-short-name res)))
 444       (if (gnus-methods-equal-p m1 m2)
 445           (progn
 446             (gnus-message
 447              9
 448              "gnus-registry-split-fancy-with-parent stripped group %s to %s"
 449              res
 450              short-res)
 451             (setq res short-res))
 452         ;; else...
 453         (gnus-message
 454          5
 455          "gnus-registry-split-fancy-with-parent ignored foreign group %s"
 456          res)
 457         (setq res nil))))
 458     res))
 459
 460 (defun gnus-registry-register-message-ids ()
 461   "Register the Message-ID of every article in the group"
 462   (unless (gnus-parameter-registry-ignore gnus-newsgroup-name)
 463     (dolist (article gnus-newsgroup-articles)
 464       (let ((id (gnus-registry-fetch-message-id-fast article)))
 465         (unless (gnus-registry-fetch-group id)
 466           (gnus-message 9 "Registry: Registering article %d with group %s"
 467                         article gnus-newsgroup-name)
 468           (gnus-registry-add-group
 469            (gnus-registry-fetch-message-id-fast article)
 470            gnus-newsgroup-name
 471            (gnus-registry-fetch-simplified-message-subject-fast article)
 472            (gnus-registry-fetch-sender-fast article)))))))
 473
 474 (defun gnus-registry-fetch-message-id-fast (article)
 475   "Fetch the Message-ID quickly, using the internal gnus-data-list function"
 476   (if (and (numberp article)
 477            (assoc article (gnus-data-list nil)))
 478       (mail-header-id (gnus-data-header (assoc article (gnus-data-list nil))))
 479     nil))
 480
 481 (defun gnus-registry-simplify-subject (subject)
 482   (if (stringp subject)
 483       (gnus-simplify-subject subject)
 484     nil))
 485
 486 (defun gnus-registry-fetch-simplified-message-subject-fast (article)
 487   "Fetch the Subject quickly, using the internal gnus-data-list function"
 488   (if (and (numberp article)
 489            (assoc article (gnus-data-list nil)))
 490       (gnus-registry-simplify-subject
 491        (mail-header-subject (gnus-data-header
 492                              (assoc article (gnus-data-list nil)))))
 493     nil))
 494
 495 (defun gnus-registry-fetch-sender-fast (article)
 496   "Fetch the Sender quickly, using the internal gnus-data-list function"
 497   (if (and (numberp article)
 498            (assoc article (gnus-data-list nil)))
 499       (mail-header-from (gnus-data-header
 500                          (assoc article (gnus-data-list nil))))
 501     nil))
 502
 503 (defun gnus-registry-grep-in-list (word list)
 504   (when word
 505     (memq nil
 506           (mapcar 'not
 507                   (mapcar
 508                    (lambda (x)
 509                      (string-match x word))
 510                    list)))))
 511
 512 (defun gnus-registry-fetch-extra (id &optional entry)
 513   "Get the extra data of a message, based on the message ID.
 514 Returns the first place where the trail finds a nonstring."
 515   (let ((entry-cache (gethash entry gnus-registry-hashtb)))
 516     (if (and entry
 517              (hash-table-p entry-cache)
 518              (gethash id entry-cache))
 519         (gethash id entry-cache)
 520       ;; else, if there is no caching possible...
 521       (let ((trail (gethash id gnus-registry-hashtb)))
 522         (when (listp trail)
 523           (dolist (crumb trail)
 524             (unless (stringp crumb)
 525               (return (gnus-registry-fetch-extra-entry crumb entry id)))))))))
 526
 527 (defun gnus-registry-fetch-extra-entry (alist &optional entry id)
 528   "Get the extra data of a message, or a specific entry in it.
 529 Update the entry cache if needed."
 530   (if (and entry id)
 531       (let ((entry-cache (gethash entry gnus-registry-hashtb))
 532             entree)
 533         (when gnus-registry-entry-caching
 534           ;; create the hash table
 535           (unless (hash-table-p entry-cache)
 536             (setq entry-cache (make-hash-table
 537                                :size 4096
 538                                :test 'equal))
 539             (puthash entry entry-cache gnus-registry-hashtb))
 540
 541           ;; get the entree from the hash table or from the alist
 542           (setq entree (gethash id entry-cache)))
 543
 544         (unless entree
 545           (setq entree (assq entry alist))
 546           (when gnus-registry-entry-caching
 547             (puthash id entree entry-cache)))
 548         entree)
 549     alist))
 550
 551 (defun gnus-registry-store-extra (id extra)
 552   "Store the extra data of a message, based on the message ID.
 553 The message must have at least one group name."
 554   (when (gnus-registry-group-count id)
 555     ;; we now know the trail has at least 1 group name, so it's not empty
 556     (let ((trail (gethash id gnus-registry-hashtb))
 557           (old-extra (gnus-registry-fetch-extra id))
 558           entry-cache)
 559       (dolist (crumb trail)
 560         (unless (stringp crumb)
 561           (dolist (entry crumb)
 562             (setq entry-cache (gethash (car entry) gnus-registry-hashtb))
 563           (when entry-cache
 564             (remhash id entry-cache))))
 565       (puthash id (cons extra (delete old-extra trail))
 566                gnus-registry-hashtb)
 567       (setq gnus-registry-dirty t)))))
 568
 569 (defun gnus-registry-store-extra-entry (id key value)
 570   "Put a specific entry in the extras field of the registry entry for id."
 571   (let* ((extra (gnus-registry-fetch-extra id))
 572          (alist (cons (cons key value)
 573                  (gnus-assq-delete-all key (gnus-registry-fetch-extra id)))))
 574     (gnus-registry-store-extra id alist)))
 575
 576 (defun gnus-registry-fetch-group (id)
 577   "Get the group of a message, based on the message ID.
 578 Returns the first place where the trail finds a group name."
 579   (when (gnus-registry-group-count id)
 580     ;; we now know the trail has at least 1 group name
 581     (let ((trail (gethash id gnus-registry-hashtb)))
 582       (dolist (crumb trail)
 583         (when (stringp crumb)
 584           (return (if gnus-registry-use-long-group-names
 585                        crumb
 586                      (gnus-group-short-name crumb))))))))
 587
 588 (defun gnus-registry-group-count (id)
 589   "Get the number of groups of a message, based on the message ID."
 590   (let ((trail (gethash id gnus-registry-hashtb)))
 591     (if (and trail (listp trail))
 592         (apply '+ (mapcar (lambda (x) (if (stringp x) 1 0)) trail))
 593       0)))
 594
 595 (defun gnus-registry-delete-group (id group)
 596   "Delete a group for a message, based on the message ID."
 597   (when group
 598     (when id
 599       (let ((trail (gethash id gnus-registry-hashtb))
 600             (group (gnus-group-short-name group)))
 601         (puthash id (if trail
 602                         (delete group trail)
 603                       nil)
 604                  gnus-registry-hashtb))
 605       ;; now, clear the entry if there are no more groups
 606       (when gnus-registry-trim-articles-without-groups
 607         (unless (gnus-registry-group-count id)
 608           (gnus-registry-delete-id id)))
 609       (gnus-registry-store-extra-entry id 'mtime (current-time)))))
 610
 611 (defun gnus-registry-delete-id (id)
 612   "Delete a message ID from the registry."
 613   (when (stringp id)
 614     (remhash id gnus-registry-hashtb)
 615     (maphash
 616      (lambda (key value)
 617        (when (hash-table-p value)
 618          (remhash id value)))
 619      gnus-registry-hashtb)))
 620
 621 (defun gnus-registry-add-group (id group &optional subject sender)
 622   "Add a group for a message, based on the message ID."
 623   (when group
 624     (when (and id
 625                (not (string-match "totally-fudged-out-message-id" id)))
 626       (let ((full-group group)
 627             (group (if gnus-registry-use-long-group-names
 628                        group
 629                      (gnus-group-short-name group))))
 630         (gnus-registry-delete-group id group)
 631
 632         (unless gnus-registry-use-long-group-names ;; unnecessary in this case
 633           (gnus-registry-delete-group id full-group))
 634
 635         (let ((trail (gethash id gnus-registry-hashtb)))
 636           (puthash id (if trail
 637                           (cons group trail)
 638                         (list group))
 639                    gnus-registry-hashtb)
 640
 641           (when (and (gnus-registry-track-subject-p)
 642                      subject)
 643             (gnus-registry-store-extra-entry
 644              id
 645              'subject
 646              (gnus-registry-simplify-subject subject)))
 647           (when (and (gnus-registry-track-sender-p)
 648                      sender)
 649             (gnus-registry-store-extra-entry
 650              id
 651              'sender
 652              sender))
 653
 654           (gnus-registry-store-extra-entry id 'mtime (current-time)))))))
 655
 656 (defun gnus-registry-clear ()
 657   "Clear the Gnus registry."
 658   (interactive)
 659   (setq gnus-registry-alist nil)
 660   (setq gnus-registry-hashtb (alist-to-hashtable gnus-registry-alist))
 661   (setq gnus-registry-dirty t))
 662
 663 ;;;###autoload
 664 (defun gnus-registry-initialize ()
 665   (interactive)
 666   (setq gnus-registry-install t)
 667   (gnus-registry-install-hooks)
 668   (gnus-registry-read))
 669
 670 ;;;###autoload
 671 (defun gnus-registry-install-hooks ()
 672   "Install the registry hooks."
 673   (interactive)
 674   (add-hook 'gnus-summary-article-move-hook 'gnus-registry-action)
 675   (add-hook 'gnus-summary-article-delete-hook 'gnus-registry-action)
 676   (add-hook 'gnus-summary-article-expire-hook 'gnus-registry-action)
 677   (add-hook 'nnmail-spool-hook 'gnus-registry-spool-action)
 678
 679   (add-hook 'gnus-save-newsrc-hook 'gnus-registry-save)
 680   (add-hook 'gnus-read-newsrc-el-hook 'gnus-registry-read)
 681
 682   (add-hook 'gnus-summary-prepare-hook 'gnus-registry-register-message-ids))
 683
 684 (defun gnus-registry-unload-hook ()
 685   "Uninstall the registry hooks."
 686   (interactive)
 687   (remove-hook 'gnus-summary-article-move-hook 'gnus-registry-action)
 688   (remove-hook 'gnus-summary-article-delete-hook 'gnus-registry-action)
 689   (remove-hook 'gnus-summary-article-expire-hook 'gnus-registry-action)
 690   (remove-hook 'nnmail-spool-hook 'gnus-registry-spool-action)
 691
 692   (remove-hook 'gnus-save-newsrc-hook 'gnus-registry-save)
 693   (remove-hook 'gnus-read-newsrc-el-hook 'gnus-registry-read)
 694
 695   (remove-hook 'gnus-summary-prepare-hook 'gnus-registry-register-message-ids))
 696
 697 (add-hook 'gnus-registry-unload-hook 'gnus-registry-unload-hook)
 698
 699 (when gnus-registry-install
 700   (gnus-registry-install-hooks)
 701   (gnus-registry-read))
 702
 703 ;; TODO: a lot of things
 704
 705 (provide 'gnus-registry)
 706
 707 ;;; arch-tag: 5cba0a32-718a-4a97-8c91-0a15af21da94
 708 ;;; gnus-registry.el ends here