code.delx.au - gnu-emacs/blob - lisp/gnus/gnus-bcklg.el

   1 ;;; gnus-bcklg.el --- backlog functions for Gnus
   2 ;; Copyright (C) 1996,97 Free Software Foundation, Inc.
   3
   4 ;; Author: Lars Magne Ingebrigtsen <larsi@ifi.uio.no>
   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 (require 'gnus)
  29
  30 ;;;
  31 ;;; Buffering of read articles.
  32 ;;;
  33
  34 (defvar gnus-backlog-buffer " *Gnus Backlog*")
  35 (defvar gnus-backlog-articles nil)
  36 (defvar gnus-backlog-hashtb nil)
  37
  38 (defun gnus-backlog-buffer ()
  39   "Return the backlog buffer."
  40   (or (get-buffer gnus-backlog-buffer)
  41       (save-excursion
  42         (set-buffer (get-buffer-create gnus-backlog-buffer))
  43         (buffer-disable-undo (current-buffer))
  44         (setq buffer-read-only t)
  45         (gnus-add-current-to-buffer-list)
  46         (get-buffer gnus-backlog-buffer))))
  47
  48 (defun gnus-backlog-setup ()
  49   "Initialize backlog variables."
  50   (unless gnus-backlog-hashtb
  51     (setq gnus-backlog-hashtb (gnus-make-hashtable 1024))))
  52
  53 (gnus-add-shutdown 'gnus-backlog-shutdown 'gnus)
  54
  55 (defun gnus-backlog-shutdown ()
  56   "Clear all backlog variables and buffers."
  57   (when (get-buffer gnus-backlog-buffer)
  58     (kill-buffer gnus-backlog-buffer))
  59   (setq gnus-backlog-hashtb nil
  60         gnus-backlog-articles nil))
  61
  62 (defun gnus-backlog-enter-article (group number buffer)
  63   (gnus-backlog-setup)
  64   (let ((ident (intern (concat group ":" (int-to-string number))
  65                        gnus-backlog-hashtb))
  66         b)
  67     (if (memq ident gnus-backlog-articles)
  68         ()                              ; It's already kept.
  69       ;; Remove the oldest article, if necessary.
  70       (and (numberp gnus-keep-backlog)
  71            (>= (length gnus-backlog-articles) gnus-keep-backlog)
  72            (gnus-backlog-remove-oldest-article))
  73       (push ident gnus-backlog-articles)
  74       ;; Insert the new article.
  75       (save-excursion
  76         (set-buffer (gnus-backlog-buffer))
  77         (let (buffer-read-only)
  78           (goto-char (point-max))
  79           (unless (bolp)
  80             (insert "\n"))
  81           (setq b (point))
  82           (insert-buffer-substring buffer)
  83           ;; Tag the beginning of the article with the ident.
  84           (gnus-put-text-property b (1+ b) 'gnus-backlog ident))))))
  85
  86 (defun gnus-backlog-remove-oldest-article ()
  87   (save-excursion
  88     (set-buffer (gnus-backlog-buffer))
  89     (goto-char (point-min))
  90     (if (zerop (buffer-size))
  91         ()                              ; The buffer is empty.
  92       (let ((ident (get-text-property (point) 'gnus-backlog))
  93             buffer-read-only)
  94         ;; Remove the ident from the list of articles.
  95         (when ident
  96           (setq gnus-backlog-articles (delq ident gnus-backlog-articles)))
  97         ;; Delete the article itself.
  98         (delete-region
  99          (point) (next-single-property-change
 100                   (1+ (point)) 'gnus-backlog nil (point-max)))))))
 101
 102 (defun gnus-backlog-remove-article (group number)
 103   "Remove article NUMBER in GROUP from the backlog."
 104   (when (numberp number)
 105     (gnus-backlog-setup)
 106     (let ((ident (intern (concat group ":" (int-to-string number))
 107                          gnus-backlog-hashtb))
 108           beg end)
 109       (when (memq ident gnus-backlog-articles)
 110         ;; It was in the backlog.
 111         (save-excursion
 112           (set-buffer (gnus-backlog-buffer))
 113           (let (buffer-read-only)
 114             (when (setq beg (text-property-any
 115                              (point-min) (point-max) 'gnus-backlog
 116                              ident))
 117               ;; Find the end (i. e., the beginning of the next article).
 118               (setq end
 119                     (next-single-property-change
 120                      (1+ beg) 'gnus-backlog (current-buffer) (point-max)))
 121               (delete-region beg end)
 122               ;; Return success.
 123               t)))))))
 124
 125 (defun gnus-backlog-request-article (group number buffer)
 126   (when (numberp number)
 127     (gnus-backlog-setup)
 128     (let ((ident (intern (concat group ":" (int-to-string number))
 129                          gnus-backlog-hashtb))
 130           beg end)
 131       (when (memq ident gnus-backlog-articles)
 132         ;; It was in the backlog.
 133         (save-excursion
 134           (set-buffer (gnus-backlog-buffer))
 135           (if (not (setq beg (text-property-any
 136                               (point-min) (point-max) 'gnus-backlog
 137                               ident)))
 138               ;; It wasn't in the backlog after all.
 139               (ignore
 140                (setq gnus-backlog-articles (delq ident gnus-backlog-articles)))
 141             ;; Find the end (i. e., the beginning of the next article).
 142             (setq end
 143                   (next-single-property-change
 144                    (1+ beg) 'gnus-backlog (current-buffer) (point-max)))))
 145         (let ((buffer-read-only nil))
 146           (erase-buffer)
 147           (insert-buffer-substring gnus-backlog-buffer beg end)
 148           t)))))
 149
 150 (provide 'gnus-bcklg)
 151
 152 ;;; gnus-bcklg.el ends here