1;;; nnheader.el --- header access macros for Gnus and its backends
2
3;; Copyright (C) 1987, 1988, 1989, 1990, 1993, 1994,
4;;   1995, 1996, 1997, 1998, 2000, 2001, 2002, 2003,
5;;   2004, 2005, 2006, 2007 Free Software Foundation, Inc.
6
7;; Author: Masanobu UMEDA <umerin@flab.flab.fujitsu.junet>
8;;	Lars Magne Ingebrigtsen <larsi@gnus.org>
9;; Keywords: news
10
11;; This file is part of GNU Emacs.
12
13;; GNU Emacs is free software; you can redistribute it and/or modify
14;; it under the terms of the GNU General Public License as published by
15;; the Free Software Foundation; either version 2, or (at your option)
16;; any later version.
17
18;; GNU Emacs is distributed in the hope that it will be useful,
19;; but WITHOUT ANY WARRANTY; without even the implied warranty of
20;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
21;; GNU General Public License for more details.
22
23;; You should have received a copy of the GNU General Public License
24;; along with GNU Emacs; see the file COPYING.  If not, write to the
25;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
26;; Boston, MA 02110-1301, USA.
27
28;;; Commentary:
29
30;;; Code:
31
32(eval-when-compile (require 'cl))
33
34(defvar nnmail-extra-headers)
35
36;; Requiring `gnus-util' at compile time creates a circular
37;; dependency between nnheader.el and gnus-util.el.
38;;(eval-when-compile (require 'gnus-util))
39
40(require 'mail-utils)
41(require 'mm-util)
42(require 'gnus-util)
43(eval-and-compile
44  (autoload 'gnus-sorted-intersection "gnus-range")
45  (autoload 'gnus-intersection "gnus-range")
46  (autoload 'gnus-sorted-complement "gnus-range")
47  (autoload 'gnus-sorted-difference "gnus-range"))
48
49(defcustom gnus-verbose-backends 7
50  "Integer that says how verbose the Gnus backends should be.
51The higher the number, the more messages the Gnus backends will flash
52to say what it's doing.  At zero, the Gnus backends will be totally
53mute; at five, they will display most important messages; and at ten,
54they will keep on jabbering all the time."
55  :group 'gnus-start
56  :type 'integer)
57
58(defcustom gnus-nov-is-evil nil
59  "If non-nil, Gnus backends will never output headers in the NOV format."
60  :group 'gnus-server
61  :type 'boolean)
62
63(defvar nnheader-max-head-length 8192
64  "*Max length of the head of articles.
65
66Value is an integer, nil, or t.  nil means read in chunks of a file
67indefinitely until a complete head is found\; t means always read the
68entire file immediately, disregarding `nnheader-head-chop-length'.
69
70Integer values will in effect be rounded up to the nearest multiple of
71`nnheader-head-chop-length'.")
72
73(defvar nnheader-head-chop-length 2048
74  "*Length of each read operation when trying to fetch HEAD headers.")
75
76(defvar nnheader-read-timeout
77  (if (string-match "windows-nt\\|os/2\\|emx\\|cygwin"
78		    (symbol-name system-type))
79      ;; http://thread.gmane.org/v9655t3pjo.fsf@marauder.physik.uni-ulm.de
80      ;;
81      ;; IIRC, values lower than 1.0 didn't/don't work on Windows/DOS.
82      ;;
83      ;; There should probably be a runtime test to determine the timing
84      ;; resolution, or a primitive to report it.  I don't know off-hand
85      ;; what's possible.  Perhaps better, maybe the Windows/DOS primitive
86      ;; could round up non-zero timeouts to a minimum of 1.0?
87      1.0
88    0.1)
89  "How long nntp should wait between checking for the end of output.
90Shorter values mean quicker response, but are more CPU intensive.")
91
92(defvar nnheader-file-name-translation-alist
93  (let ((case-fold-search t))
94    (cond
95     ((string-match "windows-nt\\|os/2\\|emx\\|cygwin"
96		    (symbol-name system-type))
97      (append (mapcar (lambda (c) (cons c ?_))
98		      '(?: ?* ?\" ?< ?> ??))
99	      (if (string-match "windows-nt\\|cygwin"
100				(symbol-name system-type))
101		  nil
102		'((?+ . ?-)))))
103     (t nil)))
104  "*Alist that says how to translate characters in file names.
105For instance, if \":\" is invalid as a file character in file names
106on your system, you could say something like:
107
108\(setq nnheader-file-name-translation-alist '((?: . ?_)))")
109
110(defvar nnheader-directory-separator-character
111  (string-to-char (substring (file-name-as-directory ".") -1))
112  "*A character used to a directory separator.")
113
114(eval-and-compile
115  (autoload 'nnmail-message-id "nnmail")
116  (autoload 'mail-position-on-field "sendmail")
117  (autoload 'message-remove-header "message")
118  (autoload 'gnus-point-at-eol "gnus-util")
119  (autoload 'gnus-buffer-live-p "gnus-util"))
120
121;;; Header access macros.
122
123;; These macros may look very much like the ones in GNUS 4.1.  They
124;; are, in a way, but you should note that the indices they use have
125;; been changed from the internal GNUS format to the NOV format.  The
126;; makes it possible to read headers from XOVER much faster.
127;;
128;; The format of a header is now:
129;; [number subject from date id references chars lines xref extra]
130;;
131;; (That next-to-last entry is defined as "misc" in the NOV format,
132;; but Gnus uses it for xrefs.)
133
134(defmacro mail-header-number (header)
135  "Return article number in HEADER."
136  `(aref ,header 0))
137
138(defmacro mail-header-set-number (header number)
139  "Set article number of HEADER to NUMBER."
140  `(aset ,header 0 ,number))
141
142(defmacro mail-header-subject (header)
143  "Return subject string in HEADER."
144  `(aref ,header 1))
145
146(defmacro mail-header-set-subject (header subject)
147  "Set article subject of HEADER to SUBJECT."
148  `(aset ,header 1 ,subject))
149
150(defmacro mail-header-from (header)
151  "Return author string in HEADER."
152  `(aref ,header 2))
153
154(defmacro mail-header-set-from (header from)
155  "Set article author of HEADER to FROM."
156  `(aset ,header 2 ,from))
157
158(defmacro mail-header-date (header)
159  "Return date in HEADER."
160  `(aref ,header 3))
161
162(defmacro mail-header-set-date (header date)
163  "Set article date of HEADER to DATE."
164  `(aset ,header 3 ,date))
165
166(defalias 'mail-header-message-id 'mail-header-id)
167(defmacro mail-header-id (header)
168  "Return Id in HEADER."
169  `(aref ,header 4))
170
171(defalias 'mail-header-set-message-id 'mail-header-set-id)
172(defmacro mail-header-set-id (header id)
173  "Set article Id of HEADER to ID."
174  `(aset ,header 4 ,id))
175
176(defmacro mail-header-references (header)
177  "Return references in HEADER."
178  `(aref ,header 5))
179
180(defmacro mail-header-set-references (header ref)
181  "Set article references of HEADER to REF."
182  `(aset ,header 5 ,ref))
183
184(defmacro mail-header-chars (header)
185  "Return number of chars of article in HEADER."
186  `(aref ,header 6))
187
188(defmacro mail-header-set-chars (header chars)
189  "Set number of chars in article of HEADER to CHARS."
190  `(aset ,header 6 ,chars))
191
192(defmacro mail-header-lines (header)
193  "Return lines in HEADER."
194  `(aref ,header 7))
195
196(defmacro mail-header-set-lines (header lines)
197  "Set article lines of HEADER to LINES."
198  `(aset ,header 7 ,lines))
199
200(defmacro mail-header-xref (header)
201  "Return xref string in HEADER."
202  `(aref ,header 8))
203
204(defmacro mail-header-set-xref (header xref)
205  "Set article XREF of HEADER to xref."
206  `(aset ,header 8 ,xref))
207
208(defmacro mail-header-extra (header)
209  "Return the extra headers in HEADER."
210  `(aref ,header 9))
211
212(defmacro mail-header-set-extra (header extra)
213  "Set the extra headers in HEADER to EXTRA."
214  `(aset ,header 9 ',extra))
215
216(defsubst make-mail-header (&optional init)
217  "Create a new mail header structure initialized with INIT."
218  (make-vector 10 init))
219
220(defsubst make-full-mail-header (&optional number subject from date id
221					   references chars lines xref
222					   extra)
223  "Create a new mail header structure initialized with the parameters given."
224  (vector number subject from date id references chars lines xref extra))
225
226;; fake message-ids: generation and detection
227
228(defvar nnheader-fake-message-id 1)
229
230(defsubst nnheader-generate-fake-message-id ()
231  (concat "fake+none+" (int-to-string (incf nnheader-fake-message-id))))
232
233(defsubst nnheader-fake-message-id-p (id)
234  (save-match-data		       ; regular message-id's are <.*>
235    (string-match "\\`fake\\+none\\+[0-9]+\\'" id)))
236
237;; Parsing headers and NOV lines.
238
239(defsubst nnheader-remove-cr-followed-by-lf ()
240  (goto-char (point-max))
241  (while (search-backward "\r\n" nil t)
242    (delete-char 1)))
243
244(defsubst nnheader-header-value ()
245  (skip-chars-forward " \t")
246  (buffer-substring (point) (gnus-point-at-eol)))
247
248(defun nnheader-parse-naked-head (&optional number)
249  ;; This function unfolds continuation lines in this buffer
250  ;; destructively.  When this side effect is unwanted, use
251  ;; `nnheader-parse-head' instead of this function.
252  (let ((case-fold-search t)
253	(buffer-read-only nil)
254	(cur (current-buffer))
255	(p (point-min))
256	in-reply-to lines ref)
257    (nnheader-remove-cr-followed-by-lf)
258    (ietf-drums-unfold-fws)
259    (subst-char-in-region (point-min) (point-max) ?\t ? )
260    (goto-char p)
261    (insert "\n")
262    (prog1
263	;; This implementation of this function, with nine
264	;; search-forwards instead of the one re-search-forward and a
265	;; case (which basically was the old function) is actually
266	;; about twice as fast, even though it looks messier.  You
267	;; can't have everything, I guess.  Speed and elegance don't
268	;; always go hand in hand.
269	(vector
270	 ;; Number.
271	 (or number 0)
272	 ;; Subject.
273	 (progn
274	   (goto-char p)
275	   (if (search-forward "\nsubject:" nil t)
276	       (nnheader-header-value) "(none)"))
277	 ;; From.
278	 (progn
279	   (goto-char p)
280	   (if (search-forward "\nfrom:" nil t)
281	       (nnheader-header-value) "(nobody)"))
282	 ;; Date.
283	 (progn
284	   (goto-char p)
285	   (if (search-forward "\ndate:" nil t)
286	       (nnheader-header-value) ""))
287	 ;; Message-ID.
288	 (progn
289	   (goto-char p)
290	   (if (search-forward "\nmessage-id:" nil t)
291	       (buffer-substring
292		(1- (or (search-forward "<" (gnus-point-at-eol) t)
293			(point)))
294		(or (search-forward ">" (gnus-point-at-eol) t) (point)))
295	     ;; If there was no message-id, we just fake one to make
296	     ;; subsequent routines simpler.
297	     (nnheader-generate-fake-message-id)))
298	 ;; References.
299	 (progn
300	   (goto-char p)
301	   (if (search-forward "\nreferences:" nil t)
302	       (nnheader-header-value)
303	     ;; Get the references from the in-reply-to header if
304	     ;; there were no references and the in-reply-to header
305	     ;; looks promising.
306	     (if (and (search-forward "\nin-reply-to:" nil t)
307		      (setq in-reply-to (nnheader-header-value))
308		      (string-match "<[^\n>]+>" in-reply-to))
309		 (let (ref2)
310		   (setq ref (substring in-reply-to (match-beginning 0)
311					(match-end 0)))
312		   (while (string-match "<[^\n>]+>"
313					in-reply-to (match-end 0))
314		     (setq ref2 (substring in-reply-to (match-beginning 0)
315					   (match-end 0)))
316		     (when (> (length ref2) (length ref))
317		       (setq ref ref2)))
318		   ref)
319	       nil)))
320	 ;; Chars.
321	 0
322	 ;; Lines.
323	 (progn
324	   (goto-char p)
325	   (if (search-forward "\nlines: " nil t)
326	       (if (numberp (setq lines (read cur)))
327		   lines 0)
328	     0))
329	 ;; Xref.
330	 (progn
331	   (goto-char p)
332	   (and (search-forward "\nxref:" nil t)
333		(nnheader-header-value)))
334	 ;; Extra.
335	 (when nnmail-extra-headers
336	   (let ((extra nnmail-extra-headers)
337		 out)
338	     (while extra
339	       (goto-char p)
340	       (when (search-forward
341		      (concat "\n" (symbol-name (car extra)) ":") nil t)
342		 (push (cons (car extra) (nnheader-header-value))
343		       out))
344	       (pop extra))
345	     out)))
346      (goto-char p)
347      (delete-char 1))))
348
349(defun nnheader-parse-head (&optional naked)
350  (let ((cur (current-buffer)) num beg end)
351    (when (if naked
352	      (setq num 0
353		    beg (point-min)
354		    end (point-max))
355	    (goto-char (point-min))
356	    ;; Search to the beginning of the next header.  Error
357	    ;; messages do not begin with 2 or 3.
358	    (when (re-search-forward "^[23][0-9]+ " nil t)
359	      (end-of-line)
360	      (setq num (read cur)
361		    beg (point)
362		    end (if (search-forward "\n.\n" nil t)
363			    (- (point) 2)
364			  (point)))))
365      (with-temp-buffer
366	(insert-buffer-substring cur beg end)
367	(nnheader-parse-naked-head num)))))
368
369(defmacro nnheader-nov-skip-field ()
370  '(search-forward "\t" eol 'move))
371
372(defmacro nnheader-nov-field ()
373  '(buffer-substring (point) (if (nnheader-nov-skip-field) (1- (point)) eol)))
374
375(defmacro nnheader-nov-read-integer ()
376  '(prog1
377       (if (eq (char-after) ?\t)
378	   0
379	 (let ((num (condition-case nil
380			(read (current-buffer))
381		      (error nil))))
382	   (if (numberp num) num 0)))
383     (or (eobp) (forward-char 1))))
384
385(defmacro nnheader-nov-parse-extra ()
386  '(let (out string)
387     (while (not (memq (char-after) '(?\n nil)))
388       (setq string (nnheader-nov-field))
389       (when (string-match "^\\([^ :]+\\): " string)
390	 (push (cons (intern (match-string 1 string))
391		     (substring string (match-end 0)))
392	       out)))
393     out))
394
395(defmacro nnheader-nov-read-message-id ()
396  '(let ((id (nnheader-nov-field)))
397     (if (string-match "^<[^>]+>$" id)
398	 id
399       (nnheader-generate-fake-message-id))))
400
401(defun nnheader-parse-nov ()
402  (let ((eol (gnus-point-at-eol)))
403    (vector
404     (nnheader-nov-read-integer)	; number
405     (nnheader-nov-field)		; subject
406     (nnheader-nov-field)		; from
407     (nnheader-nov-field)		; date
408     (nnheader-nov-read-message-id)	; id
409     (nnheader-nov-field)		; refs
410     (nnheader-nov-read-integer)	; chars
411     (nnheader-nov-read-integer)	; lines
412     (if (eq (char-after) ?\n)
413	 nil
414       (if (looking-at "Xref: ")
415	   (goto-char (match-end 0)))
416       (nnheader-nov-field))		; Xref
417     (nnheader-nov-parse-extra))))	; extra
418
419(defun nnheader-insert-nov (header)
420  (princ (mail-header-number header) (current-buffer))
421  (let ((p (point)))
422    (insert
423     "\t"
424     (or (mail-header-subject header) "(none)") "\t"
425     (or (mail-header-from header) "(nobody)") "\t"
426     (or (mail-header-date header) "") "\t"
427     (or (mail-header-id header)
428	 (nnmail-message-id))
429     "\t"
430     (or (mail-header-references header) "") "\t")
431    (princ (or (mail-header-chars header) 0) (current-buffer))
432    (insert "\t")
433    (princ (or (mail-header-lines header) 0) (current-buffer))
434    (insert "\t")
435    (when (mail-header-xref header)
436      (insert "Xref: " (mail-header-xref header)))
437    (when (or (mail-header-xref header)
438	      (mail-header-extra header))
439      (insert "\t"))
440    (when (mail-header-extra header)
441      (let ((extra (mail-header-extra header)))
442	(while extra
443	  (insert (symbol-name (caar extra))
444		  ": " (cdar extra) "\t")
445	  (pop extra))))
446    (insert "\n")
447    (backward-char 1)
448    (while (search-backward "\n" p t)
449      (delete-char 1))
450    (forward-line 1)))
451
452(defun nnheader-parse-overview-file (file)
453  "Parse FILE and return a list of headers."
454  (mm-with-unibyte-buffer
455    (nnheader-insert-file-contents file)
456    (goto-char (point-min))
457    (let (headers)
458      (while (not (eobp))
459	(push (nnheader-parse-nov) headers)
460	(forward-line 1))
461      (nreverse headers))))
462
463(defun nnheader-write-overview-file (file headers)
464  "Write HEADERS to FILE."
465  (with-temp-file file
466    (mapcar 'nnheader-insert-nov headers)))
467
468(defun nnheader-insert-header (header)
469  (insert
470   "Subject: " (or (mail-header-subject header) "(none)") "\n"
471   "From: " (or (mail-header-from header) "(nobody)") "\n"
472   "Date: " (or (mail-header-date header) "") "\n"
473   "Message-ID: " (or (mail-header-id header) (nnmail-message-id)) "\n"
474   "References: " (or (mail-header-references header) "") "\n"
475   "Lines: ")
476  (princ (or (mail-header-lines header) 0) (current-buffer))
477  (insert "\n\n"))
478
479(defun nnheader-insert-article-line (article)
480  (goto-char (point-min))
481  (insert "220 ")
482  (princ article (current-buffer))
483  (insert " Article retrieved.\n")
484  (search-forward "\n\n" nil 'move)
485  (delete-region (point) (point-max))
486  (forward-char -1)
487  (insert "."))
488
489(defun nnheader-nov-delete-outside-range (beg end)
490  "Delete all NOV lines that lie outside the BEG to END range."
491  ;; First we find the first wanted line.
492  (nnheader-find-nov-line beg)
493  (delete-region (point-min) (point))
494  ;; Then we find the last wanted line.
495  (when (nnheader-find-nov-line end)
496    (forward-line 1))
497  (delete-region (point) (point-max)))
498
499(defun nnheader-find-nov-line (article)
500  "Put point at the NOV line that start with ARTICLE.
501If ARTICLE doesn't exist, put point where that line
502would have been.  The function will return non-nil if
503the line could be found."
504  ;; This function basically does a binary search.
505  (let ((max (point-max))
506	(min (goto-char (point-min)))
507	(cur (current-buffer))
508	(prev (point-min))
509	num found)
510    (while (not found)
511      (goto-char (+ min (/ (- max min) 2)))
512      (beginning-of-line)
513      (if (or (= (point) prev)
514	      (eobp))
515	  (setq found t)
516	(setq prev (point))
517	(while (and (not (numberp (setq num (read cur))))
518		    (not (eobp)))
519	  (gnus-delete-line))
520	(cond ((> num article)
521	       (setq max (point)))
522	      ((< num article)
523	       (setq min (point)))
524	      (t
525	       (setq found 'yes)))))
526    ;; We may be at the first line.
527    (when (and (not num)
528	       (not (eobp)))
529      (setq num (read cur)))
530    ;; Now we may have found the article we're looking for, or we
531    ;; may be somewhere near it.
532    (when (and (not (eq found 'yes))
533	       (not (eq num article)))
534      (setq found (point))
535      (while (and (< (point) max)
536		  (or (not (numberp num))
537		      (< num article)))
538	(forward-line 1)
539	(setq found (point))
540	(or (eobp)
541	    (= (setq num (read cur)) article)))
542      (unless (eq num article)
543	(goto-char found)))
544    (beginning-of-line)
545    (eq num article)))
546
547;; Various cruft the backends and Gnus need to communicate.
548
549(defvar nntp-server-buffer nil)
550(defvar nntp-process-response nil)
551(defvar news-reply-yank-from nil)
552(defvar news-reply-yank-message-id nil)
553
554(defvar nnheader-callback-function nil)
555
556(defun nnheader-init-server-buffer ()
557  "Initialize the Gnus-backend communication buffer."
558  (save-excursion
559    (unless (gnus-buffer-live-p nntp-server-buffer)
560      (setq nntp-server-buffer (get-buffer-create " *nntpd*")))
561    (set-buffer nntp-server-buffer)
562    (mm-enable-multibyte)
563    (erase-buffer)
564    (kill-all-local-variables)
565    (setq case-fold-search t)		;Should ignore case.
566    (set (make-local-variable 'nntp-process-response) nil)
567    t))
568
569;;; Various functions the backends use.
570
571(defun nnheader-file-error (file)
572  "Return a string that says what is wrong with FILE."
573  (format
574   (cond
575    ((not (file-exists-p file))
576     "%s does not exist")
577    ((file-directory-p file)
578     "%s is a directory")
579    ((not (file-readable-p file))
580     "%s is not readable"))
581   file))
582
583(defun nnheader-insert-head (file)
584  "Insert the head of the article."
585  (when (file-exists-p file)
586    (if (eq nnheader-max-head-length t)
587	;; Just read the entire file.
588	(nnheader-insert-file-contents file)
589      ;; Read blocks of the size specified by `nnheader-head-chop-length'
590      ;; until we find a separator.
591      (let ((beg 0)
592	    (start (point))
593	    ;; Use `binary' to prevent the contents from being decoded,
594	    ;; or it will change the number of characters that
595	    ;; `insert-file-contents' returns.
596	    (coding-system-for-read 'binary))
597	(while (and (eq nnheader-head-chop-length
598			(nth 1 (mm-insert-file-contents
599				file nil beg
600				(incf beg nnheader-head-chop-length))))
601		    ;; CRLF or CR might be used for the line-break code.
602		    (prog1 (not (re-search-forward "\n\r?\n\\|\r\r" nil t))
603		      (goto-char (point-max)))
604		    (or (null nnheader-max-head-length)
605			(< beg nnheader-max-head-length))))
606	;; Finally decode the contents.
607	(when (mm-coding-system-p nnheader-file-coding-system)
608	  (mm-decode-coding-region start (point-max)
609				   nnheader-file-coding-system))))
610    t))
611
612(defun nnheader-article-p ()
613  "Say whether the current buffer looks like an article."
614  (goto-char (point-min))
615  (if (not (search-forward "\n\n" nil t))
616      nil
617    (narrow-to-region (point-min) (1- (point)))
618    (goto-char (point-min))
619    (while (looking-at "[a-zA-Z][^ \t]+:.*\n\\([ \t].*\n\\)*\\|From .*\n")
620      (goto-char (match-end 0)))
621    (prog1
622	(eobp)
623      (widen))))
624
625(defun nnheader-insert-references (references message-id)
626  "Insert a References header based on REFERENCES and MESSAGE-ID."
627  (if (and (not references) (not message-id))
628      ;; This is invalid, but not all articles have Message-IDs.
629      ()
630    (mail-position-on-field "References")
631    (let ((begin (gnus-point-at-bol))
632	  (fill-column 78)
633	  (fill-prefix "\t"))
634      (when references
635	(insert references))
636      (when (and references message-id)
637	(insert " "))
638      (when message-id
639	(insert message-id))
640      ;; Fold long References lines to conform to RFC1036 (sort of).
641      ;; The region must end with a newline to fill the region
642      ;; without inserting extra newline.
643      (fill-region-as-paragraph begin (1+ (point))))))
644
645(defun nnheader-replace-header (header new-value)
646  "Remove HEADER and insert the NEW-VALUE."
647  (save-excursion
648    (save-restriction
649      (nnheader-narrow-to-headers)
650      (prog1
651	  (message-remove-header header)
652	(goto-char (point-max))
653	(insert header ": " new-value "\n")))))
654
655(defun nnheader-narrow-to-headers ()
656  "Narrow to the head of an article."
657  (widen)
658  (narrow-to-region
659   (goto-char (point-min))
660   (if (search-forward "\n\n" nil t)
661       (1- (point))
662     (point-max)))
663  (goto-char (point-min)))
664
665(defun nnheader-remove-body ()
666  "Remove the body from an article in this current buffer."
667  (goto-char (point-min))
668  (when (re-search-forward "\n\r?\n" nil t)
669    (delete-region (point) (point-max))))
670
671(defun nnheader-set-temp-buffer (name &optional noerase)
672  "Set-buffer to an empty (possibly new) buffer called NAME with undo disabled."
673  (set-buffer (get-buffer-create name))
674  (buffer-disable-undo)
675  (unless noerase
676    (erase-buffer))
677  (current-buffer))
678
679(eval-when-compile (defvar jka-compr-compression-info-list))
680(defvar nnheader-numerical-files
681  (if (boundp 'jka-compr-compression-info-list)
682      (concat "\\([0-9]+\\)\\("
683	      (mapconcat (lambda (i) (aref i 0))
684			 jka-compr-compression-info-list "\\|")
685	      "\\)?")
686    "[0-9]+$")
687  "Regexp that match numerical files.")
688
689(defvar nnheader-numerical-short-files (concat "^" nnheader-numerical-files)
690  "Regexp that matches numerical file names.")
691
692(defvar nnheader-numerical-full-files (concat "/" nnheader-numerical-files)
693  "Regexp that matches numerical full file names.")
694
695(defsubst nnheader-file-to-number (file)
696  "Take a FILE name and return the article number."
697  (if (string= nnheader-numerical-short-files "^[0-9]+$")
698      (string-to-number file)
699    (string-match nnheader-numerical-short-files file)
700    (string-to-number (match-string 0 file))))
701
702(defvar nnheader-directory-files-is-safe
703  (or (eq system-type 'windows-nt)
704      (and (not (featurep 'xemacs))
705	   (> emacs-major-version 20)))
706  "If non-nil, Gnus believes `directory-files' is safe.
707It has been reported numerous times that `directory-files' fails with
708an alarming frequency on NFS mounted file systems. If it is nil,
709`nnheader-directory-files-safe' is used.")
710
711(defun nnheader-directory-files-safe (&rest args)
712  "Execute `directory-files' twice and returns the longer result."
713  (let ((first (apply 'directory-files args))
714	(second (apply 'directory-files args)))
715    (if (> (length first) (length second))
716	first
717      second)))
718
719(defun nnheader-directory-articles (dir)
720  "Return a list of all article files in directory DIR."
721  (mapcar 'nnheader-file-to-number
722	  (if nnheader-directory-files-is-safe
723	      (directory-files
724	       dir nil nnheader-numerical-short-files t)
725	    (nnheader-directory-files-safe
726	     dir nil nnheader-numerical-short-files t))))
727
728(defun nnheader-article-to-file-alist (dir)
729  "Return an alist of article/file pairs in DIR."
730  (mapcar (lambda (file) (cons (nnheader-file-to-number file) file))
731	  (if nnheader-directory-files-is-safe
732	      (directory-files
733	       dir nil nnheader-numerical-short-files t)
734	    (nnheader-directory-files-safe
735	     dir nil nnheader-numerical-short-files t))))
736
737(defun nnheader-fold-continuation-lines ()
738  "Fold continuation lines in the current buffer."
739  (nnheader-replace-regexp "\\(\r?\n[ \t]+\\)+" " "))
740
741(defun nnheader-translate-file-chars (file &optional full)
742  "Translate FILE into something that can be a file name.
743If FULL, translate everything."
744  (if (null nnheader-file-name-translation-alist)
745      ;; No translation is necessary.
746      file
747    (let* ((i 0)
748	   trans leaf path len)
749      (if full
750	  ;; Do complete translation.
751	  (setq leaf (copy-sequence file)
752		path ""
753		i (if (and (< 1 (length leaf)) (eq ?: (aref leaf 1)))
754		      2 0))
755	;; We translate -- but only the file name.  We leave the directory
756	;; alone.
757	(if (and (featurep 'xemacs)
758		 (memq system-type '(cygwin32 win32 w32 mswindows windows-nt
759					      cygwin)))
760	    ;; This is needed on NT and stuff, because
761	    ;; file-name-nondirectory is not enough to split
762	    ;; file names, containing ':', e.g.
763	    ;; "d:\\Work\\News\\nntp+news.fido7.ru:fido7.ru.gnu.SCORE"
764	    ;;
765	    ;; we are trying to correctly split such names:
766	    ;; "d:file.name" -> "a:" "file.name"
767	    ;; "aaa:bbb.ccc" -> "" "aaa:bbb.ccc"
768	    ;; "d:aaa\\bbb:ccc"   -> "d:aaa\\" "bbb:ccc"
769	    ;; etc.
770	    ;; to translate then only the file name part.
771	    (progn
772	      (setq leaf file
773		    path "")
774	      (if (string-match "\\(^\\w:\\|[/\\]\\)\\([^/\\]+\\)$" file)
775		  (setq leaf (substring file (match-beginning 2))
776			path (substring file 0 (match-beginning 2)))))
777	  ;; Emacs DTRT, says andrewi.
778	  (setq leaf (file-name-nondirectory file)
779		path (file-name-directory file))))
780      (setq len (length leaf))
781      (while (< i len)
782	(when (setq trans (cdr (assq (aref leaf i)
783				     nnheader-file-name-translation-alist)))
784	  (aset leaf i trans))
785	(incf i))
786      (concat path leaf))))
787
788(defun nnheader-report (backend &rest args)
789  "Report an error from the BACKEND.
790The first string in ARGS can be a format string."
791  (set (intern (format "%s-status-string" backend))
792       (if (< (length args) 2)
793	   (car args)
794	 (apply 'format args)))
795  nil)
796
797(defun nnheader-get-report (backend)
798  "Get the most recent report from BACKEND."
799  (condition-case ()
800      (nnheader-message 5 "%s" (symbol-value (intern (format "%s-status-string"
801							     backend))))
802    (error (nnheader-message 5 ""))))
803
804(defun nnheader-insert (format &rest args)
805  "Clear the communication buffer and insert FORMAT and ARGS into the buffer.
806If FORMAT isn't a format string, it and all ARGS will be inserted
807without formatting."
808  (save-excursion
809    (set-buffer nntp-server-buffer)
810    (erase-buffer)
811    (if (string-match "%" format)
812	(insert (apply 'format format args))
813      (apply 'insert format args))
814    t))
815
816(defsubst nnheader-replace-chars-in-string (string from to)
817  (mm-subst-char-in-string from to string))
818
819(defun nnheader-replace-duplicate-chars-in-string (string from to)
820  "Replace characters in STRING from FROM to TO."
821  (let ((string (substring string 0))	;Copy string.
822	(len (length string))
823	(idx 0) prev i)
824    ;; Replace all occurrences of FROM with TO.
825    (while (< idx len)
826      (setq i (aref string idx))
827      (when (and (eq prev from) (= i from))
828	(aset string (1- idx) to)
829	(aset string idx to))
830      (setq prev i)
831      (setq idx (1+ idx)))
832    string))
833
834(defun nnheader-file-to-group (file &optional top)
835  "Return a group name based on FILE and TOP."
836  (nnheader-replace-chars-in-string
837   (if (not top)
838       file
839     (condition-case ()
840	 (substring (expand-file-name file)
841		    (length
842		     (expand-file-name
843		      (file-name-as-directory top))))
844       (error "")))
845   nnheader-directory-separator-character ?.))
846
847(defun nnheader-message (level &rest args)
848  "Message if the Gnus backends are talkative."
849  (if (or (not (numberp gnus-verbose-backends))
850	  (<= level gnus-verbose-backends))
851      (apply 'message args)
852    (apply 'format args)))
853
854(defun nnheader-be-verbose (level)
855  "Return whether the backends should be verbose on LEVEL."
856  (or (not (numberp gnus-verbose-backends))
857      (<= level gnus-verbose-backends)))
858
859(defvar nnheader-pathname-coding-system 'iso-8859-1
860  "*Coding system for file name.")
861
862(defun nnheader-group-pathname (group dir &optional file)
863  "Make file name for GROUP."
864  (concat
865   (let ((dir (file-name-as-directory (expand-file-name dir))))
866     ;; If this directory exists, we use it directly.
867     (file-name-as-directory
868      (if (file-directory-p (concat dir group))
869	  (expand-file-name group dir)
870	;; If not, we translate dots into slashes.
871	(expand-file-name (mm-encode-coding-string
872			   (nnheader-replace-chars-in-string group ?. ?/)
873			   nnheader-pathname-coding-system)
874			  dir))))
875   (cond ((null file) "")
876	 ((numberp file) (int-to-string file))
877	 (t file))))
878
879(defun nnheader-concat (dir &rest files)
880  "Concat DIR as directory to FILES."
881  (apply 'concat (file-name-as-directory dir) files))
882
883(defun nnheader-ms-strip-cr ()
884  "Strip ^M from the end of all lines."
885  (save-excursion
886    (nnheader-remove-cr-followed-by-lf)))
887
888(defun nnheader-file-size (file)
889  "Return the file size of FILE or 0."
890  (or (nth 7 (file-attributes file)) 0))
891
892(defun nnheader-find-etc-directory (package &optional file first)
893  "Go through `load-path' and find the \"../etc/PACKAGE\" directory.
894This function will look in the parent directory of each `load-path'
895entry, and look for the \"etc\" directory there.
896If FILE, find the \".../etc/PACKAGE\" file instead.
897If FIRST is non-nil, return the directory or the file found at the
898first.  Otherwise, find the newest one, though it may take a time."
899  (let ((path load-path)
900	dir results)
901    ;; We try to find the dir by looking at the load path,
902    ;; stripping away the last component and adding "etc/".
903    (while path
904      (if (and (car path)
905	       (file-exists-p
906		(setq dir (concat
907			   (file-name-directory
908			    (directory-file-name (car path)))
909			   "etc/" package
910			   (if file "" "/"))))
911	       (or file (file-directory-p dir)))
912	  (progn
913	    (or (member dir results)
914		(push dir results))
915	    (setq path (if first nil (cdr path))))
916	(setq path (cdr path))))
917    (if (or first (not (cdr results)))
918	(car results)
919      (car (sort results 'file-newer-than-file-p)))))
920
921(eval-when-compile
922  (defvar ange-ftp-path-format)
923  (defvar efs-path-regexp))
924(defun nnheader-re-read-dir (path)
925  "Re-read directory PATH if PATH is on a remote system."
926  (if (and (fboundp 'efs-re-read-dir) (boundp 'efs-path-regexp))
927      (when (string-match efs-path-regexp path)
928	(efs-re-read-dir path))
929    (when (and (fboundp 'ange-ftp-re-read-dir) (boundp 'ange-ftp-path-format))
930      (when (string-match (car ange-ftp-path-format) path)
931	(ange-ftp-re-read-dir path)))))
932
933(defvar nnheader-file-coding-system 'raw-text
934  "Coding system used in file backends of Gnus.")
935
936(defun nnheader-insert-file-contents (filename &optional visit beg end replace)
937  "Like `insert-file-contents', q.v., but only reads in the file.
938A buffer may be modified in several ways after reading into the buffer due
939to advanced Emacs features, such as file-name-handlers, format decoding,
940find-file-hooks, etc.
941  This function ensures that none of these modifications will take place."
942  (let ((coding-system-for-read nnheader-file-coding-system))
943    (mm-insert-file-contents filename visit beg end replace)))
944
945(defun nnheader-insert-nov-file (file first)
946  (let ((size (nth 7 (file-attributes file)))
947	(cutoff (* 32 1024)))
948    (when size
949      (if (< size cutoff)
950          ;; If the file is small, we just load it.
951          (nnheader-insert-file-contents file)
952        ;; We start on the assumption that FIRST is pretty recent.  If
953        ;; not, we just insert the rest of the file as well.
954        (let (current)
955          (nnheader-insert-file-contents file nil (- size cutoff) size)
956          (goto-char (point-min))
957          (delete-region (point) (or (search-forward "\n" nil 'move) (point)))
958          (setq current (ignore-errors (read (current-buffer))))
959          (if (and (numberp current)
960                   (< current first))
961              t
962            (delete-region (point-min) (point-max))
963            (nnheader-insert-file-contents file)))))))
964
965(defun nnheader-find-file-noselect (&rest args)
966  "Open a file with some variables bound.
967See `find-file-noselect' for the arguments."
968  (let* ((format-alist nil)
969	 (auto-mode-alist (mm-auto-mode-alist))
970	 (default-major-mode 'fundamental-mode)
971	 (enable-local-variables nil)
972	 (after-insert-file-functions nil)
973	 (enable-local-eval nil)
974	 (coding-system-for-read nnheader-file-coding-system)
975	 (ffh (if (boundp 'find-file-hook)
976		  'find-file-hook
977		'find-file-hooks))
978	 (val (symbol-value ffh)))
979    (set ffh nil)
980    (unwind-protect
981	(apply 'find-file-noselect args)
982      (set ffh val))))
983
984(defun nnheader-directory-regular-files (dir)
985  "Return a list of all regular files in DIR."
986  (let ((files (directory-files dir t))
987	out)
988    (while files
989      (when (file-regular-p (car files))
990	(push (car files) out))
991      (pop files))
992    (nreverse out)))
993
994(defun nnheader-directory-files (&rest args)
995  "Same as `directory-files', but prune \".\" and \"..\"."
996  (let ((files (apply 'directory-files args))
997	out)
998    (while files
999      (unless (member (file-name-nondirectory (car files)) '("." ".."))
1000	(push (car files) out))
1001      (pop files))
1002    (nreverse out)))
1003
1004(defmacro nnheader-skeleton-replace (from &optional to regexp)
1005  `(let ((new (generate-new-buffer " *nnheader replace*"))
1006	 (cur (current-buffer))
1007	 (start (point-min)))
1008     (set-buffer cur)
1009     (goto-char (point-min))
1010     (while (,(if regexp 're-search-forward 'search-forward)
1011	     ,from nil t)
1012       (insert-buffer-substring
1013	cur start (prog1 (match-beginning 0) (set-buffer new)))
1014       (goto-char (point-max))
1015       ,(when to `(insert ,to))
1016       (set-buffer cur)
1017       (setq start (point)))
1018     (insert-buffer-substring
1019      cur start (prog1 (point-max) (set-buffer new)))
1020     (copy-to-buffer cur (point-min) (point-max))
1021     (kill-buffer (current-buffer))
1022     (set-buffer cur)))
1023
1024(defun nnheader-replace-string (from to)
1025  "Do a fast replacement of FROM to TO from point to `point-max'."
1026  (nnheader-skeleton-replace from to))
1027
1028(defun nnheader-replace-regexp (from to)
1029  "Do a fast regexp replacement of FROM to TO from point to `point-max'."
1030  (nnheader-skeleton-replace from to t))
1031
1032(defun nnheader-strip-cr ()
1033  "Strip all \r's from the current buffer."
1034  (nnheader-skeleton-replace "\r"))
1035
1036(defalias 'nnheader-run-at-time 'run-at-time)
1037(defalias 'nnheader-cancel-timer 'cancel-timer)
1038(defalias 'nnheader-cancel-function-timers 'cancel-function-timers)
1039(defalias 'nnheader-string-as-multibyte 'string-as-multibyte)
1040
1041(defun nnheader-accept-process-output (process)
1042  (accept-process-output
1043   process
1044   (truncate nnheader-read-timeout)
1045   (truncate (* (- nnheader-read-timeout
1046		   (truncate nnheader-read-timeout))
1047		1000))))
1048
1049(when (featurep 'xemacs)
1050  (require 'nnheaderxm))
1051
1052(run-hooks 'nnheader-load-hook)
1053
1054(provide 'nnheader)
1055
1056;;; arch-tag: a9c4b7d9-52ae-4ec9-b196-dfd93124d202
1057;;; nnheader.el ends here
1058