lisp/gnus/gnus-bcklg.el

   1 ;;; gnus-bcklg.el --- backlog functions for Gnus
   2
   3 ;; Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
   4 ;;   2005, 2006, 2007, 2008 Free Software Foundation, Inc.
   5
   6 ;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
   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 3, 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 ;;; Code:
  29
  30 (eval-when-compile (require 'cl))
  31
  32 (require 'gnus)
  33
  34 ;;;
  35 ;;; Buffering of read articles.
  36 ;;;
  37
  38 (defvar gnus-backlog-buffer " *Gnus Backlog*")
  39 (defvar gnus-backlog-articles nil)
  40 (defvar gnus-backlog-hashtb nil)
  41
  42 (defun gnus-backlog-buffer ()
  43   "Return the backlog buffer."
  44   (or (get-buffer gnus-backlog-buffer)
  45       (save-excursion
  46         (set-buffer (gnus-get-buffer-create gnus-backlog-buffer))
  47         (buffer-disable-undo)
  48         (setq buffer-read-only t)
  49         (get-buffer gnus-backlog-buffer))))
  50
  51 (defun gnus-backlog-setup ()
  52   "Initialize backlog variables."
  53   (unless gnus-backlog-hashtb
  54     (setq gnus-backlog-hashtb (gnus-make-hashtable 1024))))
  55
  56 (gnus-add-shutdown 'gnus-backlog-shutdown 'gnus)
  57
  58 (defun gnus-backlog-shutdown ()
  59   "Clear all backlog variables and buffers."
  60   (interactive)
  61   (when (get-buffer gnus-backlog-buffer)
  62     (gnus-kill-buffer gnus-backlog-buffer))
  63   (setq gnus-backlog-hashtb nil
  64         gnus-backlog-articles nil))
  65
  66 (defun gnus-backlog-enter-article (group number buffer)
  67   (when (and (numberp number)
  68              (not (string-match "^nnvirtual" group)))
  69     (gnus-backlog-setup)
  70     (let ((ident (intern (concat group ":" (int-to-string number))
  71                          gnus-backlog-hashtb))
  72           b)
  73       (if (memq ident gnus-backlog-articles)
  74           ()                            ; It's already kept.
  75       ;; Remove the oldest article, if necessary.
  76         (and (numberp gnus-keep-backlog)
  77              (>= (length gnus-backlog-articles) gnus-keep-backlog)
  78            (gnus-backlog-remove-oldest-article))
  79         (push ident gnus-backlog-articles)
  80         ;; Insert the new article.
  81         (save-excursion
  82           (set-buffer (gnus-backlog-buffer))
  83           (let (buffer-read-only)
  84             (goto-char (point-max))
  85             (unless (bolp)
  86               (insert "\n"))
  87             (setq b (point))
  88             (insert-buffer-substring buffer)
  89             ;; Tag the beginning of the article with the ident.
  90             (if (> (point-max) b)
  91               (gnus-put-text-property b (1+ b) 'gnus-backlog ident)
  92               (gnus-error 3 "Article %d is blank" number))))))))
  93
  94 (defun gnus-backlog-remove-oldest-article ()
  95   (save-excursion
  96     (set-buffer (gnus-backlog-buffer))
  97     (goto-char (point-min))
  98     (if (zerop (buffer-size))
  99         ()                              ; The buffer is empty.
 100       (let ((ident (get-text-property (point) 'gnus-backlog))
 101             buffer-read-only)
 102         ;; Remove the ident from the list of articles.
 103         (when ident
 104           (setq gnus-backlog-articles (delq ident gnus-backlog-articles)))
 105         ;; Delete the article itself.
 106         (delete-region
 107          (point) (next-single-property-change
 108                   (1+ (point)) 'gnus-backlog nil (point-max)))))))
 109
 110 (defun gnus-backlog-remove-article (group number)
 111   "Remove article NUMBER in GROUP from the backlog."
 112   (when (numberp number)
 113     (gnus-backlog-setup)
 114     (let ((ident (intern (concat group ":" (int-to-string number))
 115                          gnus-backlog-hashtb))
 116           beg end)
 117       (when (memq ident gnus-backlog-articles)
 118         ;; It was in the backlog.
 119         (save-excursion
 120           (set-buffer (gnus-backlog-buffer))
 121           (let (buffer-read-only)
 122             (when (setq beg (text-property-any
 123                              (point-min) (point-max) 'gnus-backlog
 124                              ident))
 125               ;; Find the end (i. e., the beginning of the next article).
 126               (setq end
 127                     (next-single-property-change
 128                      (1+ beg) 'gnus-backlog (current-buffer) (point-max)))
 129               (delete-region beg end)
 130               ;; Return success.
 131               t))
 132           (setq gnus-backlog-articles (delq ident gnus-backlog-articles)))))))
 133
 134 (defun gnus-backlog-request-article (group number &optional buffer)
 135   (when (and (numberp number)
 136              (not (string-match "^nnvirtual" group)))
 137     (gnus-backlog-setup)
 138     (let ((ident (intern (concat group ":" (int-to-string number))
 139                          gnus-backlog-hashtb))
 140           beg end)
 141       (when (memq ident gnus-backlog-articles)
 142         ;; It was in the backlog.
 143         (save-excursion
 144           (set-buffer (gnus-backlog-buffer))
 145           (if (not (setq beg (text-property-any
 146                               (point-min) (point-max) 'gnus-backlog
 147                               ident)))
 148               ;; It wasn't in the backlog after all.
 149               (ignore
 150                (setq gnus-backlog-articles (delq ident gnus-backlog-articles)))
 151             ;; Find the end (i. e., the beginning of the next article).
 152             (setq end
 153                   (next-single-property-change
 154                    (1+ beg) 'gnus-backlog (current-buffer) (point-max)))))
 155         (save-excursion
 156           (and buffer (set-buffer buffer))
 157           (let ((buffer-read-only nil))
 158             (erase-buffer)
 159             (insert-buffer-substring gnus-backlog-buffer beg end)))
 160         t))))
 161
 162 (provide 'gnus-bcklg)
 163
 164 ;; arch-tag: 66259e56-505a-4bba-8a0d-3552c5b94e39
 165 ;;; gnus-bcklg.el ends here