[gnus] / lisp / nnheader.el

;;; nnheader.el --- header access macros for Gnus and its backends
;; Copyright (C) 1987,88,89,90,93,94,95,96 Free Software Foundation, Inc.

;; Author: Masanobu UMEDA <umerin@flab.flab.fujitsu.junet>
;;      Lars Magne Ingebrigtsen <larsi@ifi.uio.no>
;; Keywords: news

;; This file is part of GNU Emacs.

;; GNU Emacs is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs; see the file COPYING.  If not, write to the
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.

;;; Commentary:

;; These macros may look very much like the ones in GNUS 4.1.  They
;; are, in a way, but you should note that the indices they use have
;; been changed from the internal GNUS format to the NOV format.  The
;; makes it possible to read headers from XOVER much faster.
;;
;; The format of a header is now:
;; [number subject from date id references chars lines xref]
;;
;; (That last entry is defined as "misc" in the NOV format, but Gnus
;; uses it for xrefs.)

;;; Code:

(require 'mail-utils)

(defvar nnheader-max-head-length 4096
  "*Max length of the head of articles.")

(defvar nnheader-head-chop-length 2048
  "*Length of each read operation when trying to fetch HEAD headers.")

(defvar nnheader-file-name-translation-alist nil
  "*Alist that says how to translate characters in file names.
For instance, if \":\" is illegal as a file character in file names
on your system, you could say something like:

\(setq nnheader-file-name-translation-alist '((?: . ?_)))")

(eval-and-compile
 (autoload 'nnmail-message-id "nnmail")
 (autoload 'mail-position-on-field "sendmail")
 (autoload 'message-remove-header "message")
 (autoload 'cancel-function-timers "timers"))

;;; Header access macros.

(defmacro mail-header-number (header)
  "Return article number in HEADER."
  `(aref ,header 0))

(defmacro mail-header-set-number (header number)
  "Set article number of HEADER to NUMBER."
  `(aset ,header 0 ,number))

(defmacro mail-header-subject (header)
  "Return subject string in HEADER."
  `(aref ,header 1))

(defmacro mail-header-set-subject (header subject)
  "Set article subject of HEADER to SUBJECT."
  `(aset ,header 1 ,subject))

(defmacro mail-header-from (header)
  "Return author string in HEADER."
  `(aref ,header 2))

(defmacro mail-header-set-from (header from)
  "Set article author of HEADER to FROM."
  `(aset ,header 2 ,from))

(defmacro mail-header-date (header)
  "Return date in HEADER."
  `(aref ,header 3))

(defmacro mail-header-set-date (header date)
  "Set article date of HEADER to DATE."
  `(aset ,header 3 ,date))

(defalias 'mail-header-message-id 'mail-header-id)
(defmacro mail-header-id (header)
  "Return Id in HEADER."
  `(aref ,header 4))

(defalias 'mail-header-set-message-id 'mail-header-set-id)
(defmacro mail-header-set-id (header id)
  "Set article Id of HEADER to ID."
  `(aset ,header 4 ,id))

(defmacro mail-header-references (header)
  "Return references in HEADER."
  `(aref ,header 5))

(defmacro mail-header-set-references (header ref)
  "Set article references of HEADER to REF."
  `(aset ,header 5 ,ref))

(defmacro mail-header-chars (header)
  "Return number of chars of article in HEADER."
  `(aref ,header 6))

(defmacro mail-header-set-chars (header chars)
  "Set number of chars in article of HEADER to CHARS."
  `(aset ,header 6 ,chars))

(defmacro mail-header-lines (header)
  "Return lines in HEADER."
  `(aref ,header 7))

(defmacro mail-header-set-lines (header lines)
  "Set article lines of HEADER to LINES."
  `(aset ,header 7 ,lines))

(defmacro mail-header-xref (header)
  "Return xref string in HEADER."