lisp/gnus/gnus-bcklg.el

   1 ;;; gnus-bcklg.el --- backlog functions for Gnus
   2
   3 ;; Copyright (C) 1996-2011 Free Software Foundation, Inc.
   4
   5 ;; Author: Lars Magne Ingebrigtsen <larsi@gnus.org>
   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 3 of the License, or
  13 ;; (at your option) 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.  If not, see <http://www.gnu.org/licenses/>.
  22
  23 ;;; Commentary:
  24
  25 ;;; Code:
  26
  27 (eval-when-compile (require 'cl))
  28
  29 (require 'gnus)
  30
  31 ;;;
  32 ;;; Buffering of read articles.
  33 ;;;
  34
  35 (defvar gnus-backlog-buffer " *Gnus Backlog*")
  36 (defvar gnus-backlog-articles nil)
  37 (defvar gnus-backlog-hashtb nil)
  38
  39 (defun gnus-backlog-buffer ()
  40   "Return the backlog buffer."
  41   (or (get-buffer gnus-backlog-buffer)
  42       (with-current-buffer (gnus-get-buffer-create gnus-backlog-buffer)
  43         (buffer-disable-undo)
  44         (setq buffer-read-only t)
  45         (get-buffer gnus-backlog-buffer))))
  46
  47 (defun gnus-backlog-setup ()
  48   "Initialize backlog variables."
  49   (unless gnus-backlog-hashtb
  50     (setq gnus-backlog-hashtb (gnus-make-hashtable 1024))))
  51
  52 (gnus-add-shutdown 'gnus-backlog-shutdown 'gnus)
  53
  54 (defun gnus-backlog-shutdown ()
  55   "Clear all backlog variables and buffers."
  56   (interactive)
  57   (when (get-buffer gnus-backlog-buffer)
  58     (gnus-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   (when (and (numberp number)
  64              (not (string-match "^nnvirtual" group)))
  65     (gnus-backlog-setup)
  66     (let ((ident (intern (concat group ":" (int-to-string number))
  67                          gnus-backlog-hashtb))
  68           b)
  69       (if (memq ident gnus-backlog-articles)
  70           ()                            ; It's already kept.
  71       ;; Remove the oldest article, if necessary.
  72         (and (numberp gnus-keep-backlog)
  73              (>= (length gnus-backlog-articles) gnus-keep-backlog)
  74            (gnus-backlog-remove-oldest-article))
  75         (push ident gnus-backlog-articles)
  76         ;; Insert the new article.
  77         (with-current-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   (with-current-buffer (gnus-backlog-buffer)
  91     (goto-char (point-min))
  92     (if (zerop (buffer-size))
  93         ()                              ; The buffer is empty.
  94       (let ((ident (get-text-property (point) 'gnus-backlog))
  95             buffer-read-only)
  96         ;; Remove the ident from the list of articles.
  97         (when ident
  98           (setq gnus-backlog-articles (delq ident gnus-backlog-articles)))
  99         ;; Delete the article itself.
 100         (delete-region
 101          (point) (next-single-property-change
 102                   (1+ (point)) 'gnus-backlog nil (point-max)))))))
 103
 104 (defun gnus-backlog-remove-article (group number)
 105   "Remove article NUMBER in GROUP from the backlog."
 106   (when (numberp number)
 107     (gnus-backlog-setup)
 108     (let ((ident (intern (concat group ":" (int-to-string number))
 109                          gnus-backlog-hashtb))
 110           beg end)
 111       (when (memq ident gnus-backlog-articles)
 112         ;; It was in the backlog.
 113         (with-current-buffer (gnus-backlog-buffer)
 114           (let (buffer-read-only)
 115             (when (setq beg (text-property-any
 116                              (point-min) (point-max) 'gnus-backlog
 117                              ident))
 118               ;; Find the end (i. e., the beginning of the next article).
 119               (setq end
 120                     (next-single-property-change
 121                      (1+ beg) 'gnus-backlog (current-buffer) (point-max)))
 122               (delete-region beg end)
 123               ;; Return success.
 124               t))
 125           (setq gnus-backlog-articles (delq ident gnus-backlog-articles)))))))
 126
 127 (defun gnus-backlog-request-article (group number &optional buffer)
 128   (when (and (numberp number)
 129              (not (string-match "^nnvirtual" group)))
 130     (gnus-backlog-setup)
 131     (let ((ident (intern (concat group ":" (int-to-string number))
 132                          gnus-backlog-hashtb))
 133           beg end)
 134       (when (memq ident gnus-backlog-articles)
 135         ;; It was in the backlog.
 136         (with-current-buffer (gnus-backlog-buffer)
 137           (if (not (setq beg (text-property-any
 138                               (point-min) (point-max) 'gnus-backlog
 139                               ident)))
 140               ;; It wasn't in the backlog after all.
 141               (ignore
 142                (setq gnus-backlog-articles (delq ident gnus-backlog-articles)))
 143             ;; Find the end (i. e., the beginning of the next article).
 144             (setq end
 145                   (next-single-property-change
 146                    (1+ beg) 'gnus-backlog (current-buffer) (point-max)))))
 147         (with-current-buffer (or (current-buffer) buffer)
 148           (let ((buffer-read-only nil))
 149             (erase-buffer)
 150             (insert-buffer-substring gnus-backlog-buffer beg end)))
 151         t))))
 152
 153 (provide 'gnus-bcklg)
 154
 155 ;;; gnus-bcklg.el ends here