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, 2009, 2010, 2011 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 of the License, or
  14 ;; (at your option) 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.  If not, see <http://www.gnu.org/licenses/>.
  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       (with-current-buffer (gnus-get-buffer-create gnus-backlog-buffer)
  44         (buffer-disable-undo)
  45         (setq buffer-read-only t)
  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   (interactive)
  58   (when (get-buffer gnus-backlog-buffer)
  59     (gnus-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   (when (and (numberp number)
  65              (not (string-match "^nnvirtual" group)))
  66     (gnus-backlog-setup)
  67     (let ((ident (intern (concat group ":" (int-to-string number))
  68                          gnus-backlog-hashtb))
  69           b)
  70       (if (memq ident gnus-backlog-articles)
  71           ()                            ; It's already kept.
  72       ;; Remove the oldest article, if necessary.
  73         (and (numberp gnus-keep-backlog)
  74              (>= (length gnus-backlog-articles) gnus-keep-backlog)
  75            (gnus-backlog-remove-oldest-article))
  76         (push ident gnus-backlog-articles)
  77         ;; Insert the new article.
  78         (with-current-buffer (gnus-backlog-buffer)
  79           (let (buffer-read-only)
  80             (goto-char (point-max))
  81             (unless (bolp)
  82               (insert "\n"))
  83             (setq b (point))
  84             (insert-buffer-substring buffer)
  85             ;; Tag the beginning of the article with the ident.
  86             (if (> (point-max) b)
  87               (gnus-put-text-property b (1+ b) 'gnus-backlog ident)
  88               (gnus-error 3 "Article %d is blank" number))))))))
  89
  90 (defun gnus-backlog-remove-oldest-article ()
  91   (with-current-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         (with-current-buffer (gnus-backlog-buffer)
 115           (let (buffer-read-only)
 116             (when (setq beg (text-property-any
 117                              (point-min) (point-max) 'gnus-backlog
 118                              ident))
 119               ;; Find the end (i. e., the beginning of the next article).
 120               (setq end
 121                     (next-single-property-change
 122                      (1+ beg) 'gnus-backlog (current-buffer) (point-max)))
 123               (delete-region beg end)
 124               ;; Return success.
 125               t))
 126           (setq gnus-backlog-articles (delq ident gnus-backlog-articles)))))))
 127
 128 (defun gnus-backlog-request-article (group number &optional buffer)
 129   (when (and (numberp number)
 130              (not (string-match "^nnvirtual" group)))
 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         (with-current-buffer (gnus-backlog-buffer)
 138           (if (not (setq beg (text-property-any
 139                               (point-min) (point-max) 'gnus-backlog
 140                               ident)))
 141               ;; It wasn't in the backlog after all.
 142               (ignore
 143                (setq gnus-backlog-articles (delq ident gnus-backlog-articles)))
 144             ;; Find the end (i. e., the beginning of the next article).
 145             (setq end
 146                   (next-single-property-change
 147                    (1+ beg) 'gnus-backlog (current-buffer) (point-max)))))
 148         (with-current-buffer (or (current-buffer) buffer)
 149           (let ((buffer-read-only nil))
 150             (erase-buffer)
 151             (insert-buffer-substring gnus-backlog-buffer beg end)))
 152         t))))
 153
 154 (provide 'gnus-bcklg)
 155
 156 ;;; gnus-bcklg.el ends here