lisp/gnus/gnus-bcklg.el

   1 ;;; gnus-bcklg.el --- backlog functions for Gnus
   2 ;; Copyright (C) 1996, 1997, 1998, 1999, 2000 Free Software Foundation, Inc.
   3
   4 ;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
   5 ;; Keywords: news
   6
   7 ;; This file is part of GNU Emacs.
   8
   9 ;; GNU Emacs is free software; you can redistribute it and/or modify
  10 ;; it under the terms of the GNU General Public License as published by
  11 ;; the Free Software Foundation; either version 2, or (at your option)
  12 ;; any later version.
  13
  14 ;; GNU Emacs is distributed in the hope that it will be useful,
  15 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 ;; GNU General Public License for more details.
  18
  19 ;; You should have received a copy of the GNU General Public License
  20 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  21 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  22 ;; Boston, MA 02111-1307, USA.
  23
  24 ;;; Commentary:
  25
  26 ;;; Code:
  27
  28 (eval-when-compile (require 'cl))
  29
  30 (require 'gnus)
  31
  32 ;;;
  33 ;;; Buffering of read articles.
  34 ;;;
  35
  36 (defvar gnus-backlog-buffer " *Gnus Backlog*")
  37 (defvar gnus-backlog-articles nil)
  38 (defvar gnus-backlog-hashtb nil)
  39
  40 (defun gnus-backlog-buffer ()
  41   "Return the backlog buffer."
  42   (or (get-buffer gnus-backlog-buffer)
  43       (save-excursion
  44         (set-buffer (gnus-get-buffer-create gnus-backlog-buffer))
  45         (buffer-disable-undo)
  46         (setq buffer-read-only t)
  47         (get-buffer gnus-backlog-buffer))))
  48
  49 (defun gnus-backlog-setup ()
  50   "Initialize backlog variables."
  51   (unless gnus-backlog-hashtb
  52     (setq gnus-backlog-hashtb (gnus-make-hashtable 1024))))
  53
  54 (gnus-add-shutdown 'gnus-backlog-shutdown 'gnus)
  55
  56 (defun gnus-backlog-shutdown ()
  57   "Clear all backlog variables and buffers."
  58   (when (get-buffer gnus-backlog-buffer)
  59     (kill-buffer gnus-backlog-buffer))
  60   (setq gnus-backlog-hashtb nil
  61         gnus-backlog-articles nil))
  62
  63 (defun gnus-backlog-enter-article (group number buffer)
  64   (gnus-backlog-setup)
  65   (let ((ident (intern (concat group ":" (int-to-string number))
  66                        gnus-backlog-hashtb))
  67         b)
  68     (if (memq ident gnus-backlog-articles)
  69         ()                              ; It's already kept.
  70       ;; Remove the oldest article, if necessary.
  71       (and (numberp gnus-keep-backlog)
  72            (>= (length gnus-backlog-articles) gnus-keep-backlog)
  73            (gnus-backlog-remove-oldest-article))
  74       (push ident gnus-backlog-articles)
  75       ;; Insert the new article.
  76       (save-excursion
  77         (set-buffer (gnus-backlog-buffer))
  78         (let (buffer-read-only)
  79           (goto-char (point-max))
  80           (unless (bolp)
  81             (insert "\n"))
  82           (setq b (point))
  83           (insert-buffer-substring buffer)
  84           ;; Tag the beginning of the article with the ident.
  85           (if (> (point-max) b)
  86               (gnus-put-text-property b (1+ b) 'gnus-backlog ident)
  87             (gnus-error 3 "Article %d is blank" number)))))))
  88
  89 (defun gnus-backlog-remove-oldest-article ()
  90   (save-excursion
  91     (set-buffer (gnus-backlog-buffer))
  92     (goto-char (point-min))
  93     (if (zerop (buffer-size))
  94         ()                              ; The buffer is empty.
  95       (let ((ident (get-text-property (point) 'gnus-backlog))
  96             buffer-read-only)
  97         ;; Remove the ident from the list of articles.
  98         (when ident
  99           (setq gnus-backlog-articles (delq ident gnus-backlog-articles)))
 100         ;; Delete the article itself.
 101         (delete-region
 102          (point) (next-single-property-change
 103                   (1+ (point)) 'gnus-backlog nil (point-max)))))))
 104
 105 (defun gnus-backlog-remove-article (group number)
 106   "Remove article NUMBER in GROUP from the backlog."
 107   (when (numberp number)
 108     (gnus-backlog-setup)
 109     (let ((ident (intern (concat group ":" (int-to-string number))
 110                          gnus-backlog-hashtb))
 111           beg end)
 112       (when (memq ident gnus-backlog-articles)
 113         ;; It was in the backlog.
 114         (save-excursion
 115           (set-buffer (gnus-backlog-buffer))
 116           (let (buffer-read-only)
 117             (when (setq beg (text-property-any
 118                              (point-min) (point-max) 'gnus-backlog
 119                              ident))
 120               ;; Find the end (i. e., the beginning of the next article).
 121               (setq end
 122                     (next-single-property-change
 123                      (1+ beg) 'gnus-backlog (current-buffer) (point-max)))
 124               (delete-region beg end)
 125               ;; Return success.
 126               t))
 127           (setq gnus-backlog-articles (delq ident gnus-backlog-articles)))))))
 128
 129 (defun gnus-backlog-request-article (group number &optional buffer)
 130   (when (numberp number)
 131     (gnus-backlog-setup)
 132     (let ((ident (intern (concat group ":" (int-to-string number))
 133                          gnus-backlog-hashtb))
 134           beg end)
 135       (when (memq ident gnus-backlog-articles)
 136         ;; It was in the backlog.
 137         (save-excursion
 138           (set-buffer (gnus-backlog-buffer))
 139           (if (not (setq beg (text-property-any
 140                               (point-min) (point-max) 'gnus-backlog
 141                               ident)))
 142               ;; It wasn't in the backlog after all.
 143               (ignore
 144                (setq gnus-backlog-articles (delq ident gnus-backlog-articles)))
 145             ;; Find the end (i. e., the beginning of the next article).
 146             (setq end
 147                   (next-single-property-change
 148                    (1+ beg) 'gnus-backlog (current-buffer) (point-max)))))
 149         (save-excursion
 150           (and buffer (set-buffer buffer))
 151           (let ((buffer-read-only nil))
 152             (erase-buffer)
 153             (insert-buffer-substring gnus-backlog-buffer beg end)))
 154         t))))
 155
 156 (provide 'gnus-bcklg)
 157
 158 ;;; gnus-bcklg.el ends here