emacs/lisp/gnus/nnspool.el

;;; nnspool.el --- spool access for GNU Emacs  -*- lexical-binding: t; -*-

;; Copyright (C) 1988-1990, 1993-1998, 2000-2021 Free Software
;; Foundation, Inc.

;; Author: Masanobu UMEDA <umerin@flab.flab.fujitsu.junet>
;;	Lars Magne Ingebrigtsen <larsi@gnus.org>
;; 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 3 of the License, 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.  If not, see <https://www.gnu.org/licenses/>.

;;; Commentary:

;;; Code:

(require 'nnheader)
(require 'nntp)
(require 'nnoo)
(eval-when-compile (require 'cl-lib))

;; Probably this entire thing should be obsolete.
;; It's only used to init nnspool-spool-directory, so why not just
;; set that variable's default directly?
(eval-and-compile
  (defvaralias 'news-path 'news-directory)
  (defvar news-directory (if (file-exists-p "/usr/spool/news/")
			     "/usr/spool/news/"
			   "/var/spool/news/")
    "The root directory below which all news files are stored."))

;; Ditto re obsolescence.
(defvar news-inews-program
  (cond ((file-exists-p "/usr/bin/inews") "/usr/bin/inews")
	((file-exists-p "/usr/local/inews") "/usr/local/inews")
	((file-exists-p "/usr/local/bin/inews") "/usr/local/bin/inews")
	((file-exists-p "/usr/contrib/lib/news/inews") "/usr/contrib/lib/news/inews")
	((file-exists-p "/usr/lib/news/inews") "/usr/lib/news/inews")
	(t "inews"))
  "Program to post news.")

(nnoo-declare nnspool)

(defvoo nnspool-inews-program news-inews-program
  "Program to post news.
This is most commonly `inews' or `injnews'.")

(defvoo nnspool-inews-switches '("-h" "-S")
  "Switches for nnspool-request-post to pass to `inews' for posting news.
If you are using Cnews, you probably should set this variable to nil.")

(defvoo nnspool-spool-directory
    (file-name-as-directory (if (boundp 'news-directory)
				(symbol-value 'news-directory)
			      news-path))
  "Local news spool directory.")

(defvoo nnspool-nov-directory (concat nnspool-spool-directory "over.view/")
  "Local news nov directory.")

(defvoo nnspool-lib-dir
    (if (file-exists-p "/usr/lib/news/active")
	"/usr/lib/news/"
      "/var/lib/news/")
  "Where the local news library files are stored.")

(defvoo nnspool-active-file (concat nnspool-lib-dir "active")
  "Local news active file.")

(defvoo nnspool-newsgroups-file (concat nnspool-lib-dir "newsgroups")
  "Local news newsgroups file.")

(defvoo nnspool-distributions-file (concat nnspool-lib-dir "distribs.pat")
  "Local news distributions file.")

(defvoo nnspool-history-file (concat nnspool-lib-dir "history")
  "Local news history file.")

(defvoo nnspool-active-times-file (concat nnspool-lib-dir "active.times")
  "Local news active date file.")

(defvoo nnspool-large-newsgroup 50
  "The number of articles which indicates a large newsgroup.
If the number of articles is greater than the value, verbose
messages will be shown to indicate the current status.")

(defvoo nnspool-nov-is-evil nil
  "Non-nil means that nnspool will never return NOV lines instead of headers.")

(defconst nnspool-sift-nov-with-sed nil
  "If non-nil, use sed to get the relevant portion from the overview file.
If nil, nnspool will load the entire file into a buffer and process it
there.")

(defvoo nnspool-rejected-article-hook nil
  "A hook that will be run when an article has been rejected by the server.")

(defvoo nnspool-file-coding-system nnheader-file-coding-system
  "Coding system for nnspool.")



(defconst nnspool-version "nnspool 2.0"
  "Version numbers of this version of NNSPOOL.")

(defvoo nnspool-current-directory nil
  "Current news group directory.")

(defvoo nnspool-current-group nil)
(defvoo nnspool-status-string "")


;;; Interface functions.

(nnoo-define-basics nnspool)

(deffoo nnspool-retrieve-headers (articles &optional group _server fetch-old)
  "Retrieve the headers of ARTICLES."
  (with-current-buffer nntp-server-buffer
    (erase-buffer)
    (when (nnspool-possibly-change-directory group)
      (let* ((number (length articles))
	     (count 0)
	     (default-directory nnspool-current-directory)
	     (do-message (and (numberp nnspool-large-newsgroup)
			      (> number nnspool-large-newsgroup)))
	     (nnheader-file-coding-system nnspool-file-coding-system)
	     file beg article ag)
	(if (and (numberp (car articles))
		 (nnspool-retrieve-headers-with-nov articles fetch-old))
	    ;; We successfully retrieved the NOV headers.
	    'nov
	  ;; No NOV headers here, so we do it the hard way.
	  (while (setq article (pop articles))
	    (if (stringp article)
		;; This is a Message-ID.
		(setq ag (nnspool-find-id article)
		      file (and ag (nnspool-article-pathname
				    (car ag) (cdr ag)))
		      article (cdr ag))
	      ;; This is an article in the current group.
	      (setq file (int-to-string article)))
	    ;; Insert the head of the article.
	    (when (and file
		       (file-exists-p file))
	      (insert "221 ")
	      (princ article (current-buffer))
	      (insert " Article retrieved.\n")
	      (setq beg (point))
	      (inline (nnheader-insert-head file))
	      (goto-char beg)
	      (if (search-forward "\n\n" nil t)
		  (progn
		    (forward-char -1)
		    (insert ".\n"))
		(goto-char (point-max))
		(if (bolp)
		    (insert ".\n")
		  (insert "\n.\n")))
	      (delete-region (point) (point-max)))

	    (and do-message
		 (zerop (% (cl-incf count) 20))
		 (nnheader-message 5 "nnspool: Receiving headers... %d%%"
				   (floor (* count 100.0) number))))

	  (when do-message
	    (nnheader-message 5 "nnspool: Receiving headers...done"))

	  ;; Fold continuation lines.
	  (nnheader-fold-continuation-lines)
	  'headers)))))

(deffoo nnspool-open-server (server &optional defs)
  (nnoo-change-server 'nnspool server defs)
  (cond
   ((not (file-exists-p nnspool-spool-directory))
    (nnspool-close-server)
    (nnheader-report 'nnspool "Spool directory doesn't exist: %s"
		     nnspool-spool-directory))
   ((not (file-directory-p
	  (directory-file-name
	   (file-truename nnspool-spool-directory))))
    (nnspool-close-server)
    (nnheader-report 'nnspool "Not a directory: %s" nnspool-spool-directory))
   ((not (file-exists-p nnspool-active-file))
    (nnheader-report 'nnspool "The active file doesn't exist: %s"
		     nnspool-active-file))
   (t
    (nnheader-report 'nnspool "Opened server %s using directory %s"
		     server nnspool-spool-directory)
    t)))

(deffoo nnspool-request-article (id &optional group _server buffer)
  "Select article by message ID (or number)."
  (nnspool-possibly-change-directory group)
  (let ((nntp-server-buffer (or buffer nntp-server-buffer))
	file ag)
    (if (stringp id)
	;; This is a Message-ID.
	(when (setq ag (nnspool-find-id id))
	  (setq file (nnspool-article-pathname (car ag) (cdr ag))))
      (setq file (nnspool-article-pathname nnspool-current-group id)))
    (and file
	 (file-exists-p file)
	 (not (file-directory-p file))
	 (save-excursion (nnspool-find-file file))
	 ;; We return the article number and group name.
	 (if (numberp id)
	     (cons nnspool-current-group id)
	   ag))))

(deffoo nnspool-request-body (id &optional group _server)
  "Select article body by message ID (or number)."
  (nnspool-possibly-change-directory group)
  (let ((res (nnspool-request-article id)))
    (when res
      (with-current-buffer nntp-server-buffer
	(goto-char (point-min))
	(when (search-forward "\n\n" nil t)
	  (delete-region (point-min) (point)))
	res))))

(deffoo nnspool-request-head (id &optional group _server)
  "Select article head by message ID (or number)."
  (nnspool-possibly-change-directory group)
  (let ((res (nnspool-request-article id)))
    (when res
      (with-current-buffer nntp-server-buffer
	(goto-char (point-min))
	(when (search-forward "\n\n" nil t)
	  (delete-region (1- (point)) (point-max)))
	(nnheader-fold-continuation-lines)))
    res))

(deffoo nnspool-request-group (group &optional _server dont-check _info)
  "Select news GROUP."
  (let ((pathname (nnspool-article-pathname group))
	dir)
    (if (not (file-directory-p pathname))
	(nnheader-report
	 'nnspool "Invalid group name (no such directory): %s" group)
      (setq nnspool-current-directory pathname)
      (nnheader-report 'nnspool "Selected group %s" group)
      (if dont-check
	  (progn
	    (nnheader-report 'nnspool "Selected group %s" group)
	    t)
	;; Yes, completely empty spool directories *are* possible.
	;; Fix by Sudish Joseph <joseph@cis.ohio-state.edu>
	(when (setq dir (directory-files pathname nil "\\`[0-9]+\\'" t))
	  (setq dir (sort (mapcar #'string-to-number dir) #'<)))
	(if dir
	    (nnheader-insert
	     "211 %d %d %d %s\n" (length dir) (car dir)
	     (car (last dir)) group)
	  (nnheader-report 'nnspool "Empty group %s" group)
	  (nnheader-insert "211 0 0 0 %s\n" group))))))

(deffoo nnspool-request-type (_group &optional _article)
  'news)

(deffoo nnspool-close-group (_group &optional _server)
  t)

(deffoo nnspool-request-list (&optional _server)
  "List active newsgroups."
  (save-excursion
    (or (nnspool-find-file nnspool-active-file)
	(nnheader-report 'nnspool (nnheader-file-error nnspool-active-file)))))

(deffoo nnspool-request-list-newsgroups (&optional _server)
  "List newsgroups (defined in NNTP2)."
  (save-excursion
    (or (nnspool-find-file nnspool-newsgroups-file)
	(nnheader-report 'nnspool (nnheader-file-error
				   nnspool-newsgroups-file)))))

(deffoo nnspool-request-list-distributions (&optional _server)
  "List distributions (defined in NNTP2)."
  (save-excursion
    (or (nnspool-find-file nnspool-distributions-file)
	(nnheader-report 'nnspool (nnheader-file-error
				   nnspool-distributions-file)))))

;; Suggested by Hallvard B Furuseth <h.b.furuseth@usit.uio.no>.
(deffoo nnspool-request-newgroups (date &optional _server)
  "List groups created after DATE."
  (if (nnspool-find-file nnspool-active-times-file)
      (save-excursion
	;; Find the last valid line.
	(goto-char (point-max))
	(while (and (not (looking-at
			  "\\([^ ]+\\) +\\([0-9]+\\)[0-9][0-9][0-9] "))
		    (zerop (forward-line -1))))
	(let ((seconds (time-convert (date-to-time date) 'integer))
	      groups)
	  ;; Go through lines and add the latest groups to a list.
	  (while (and (looking-at "\\([^ ]+\\) +[0-9]+ ")
		      (progn
			(goto-char (match-end 1))
			(< seconds (read (current-buffer))))
		      (progn
			(push (buffer-substring
			       (match-beginning 1) (match-end 1))
			      groups)
			(zerop (forward-line -1)))))
	  (erase-buffer)
	  (dolist (group groups)
	    (insert group " 0 0 y\n")))
	t)
    nil))

(deffoo nnspool-request-post (&optional _server)
  "Post a new news in current buffer."
  (save-excursion
    (let* ((process-connection-type nil) ; t bugs out on Solaris
	   (inews-buffer (generate-new-buffer " *nnspool post*"))
	   (buf (current-buffer))
	   (proc
	    (condition-case err
		(apply #'start-process "*nnspool inews*" inews-buffer
		       nnspool-inews-program nnspool-inews-switches)
	      (error
	       (nnheader-report 'nnspool "inews error: %S" err)))))
      (if (not proc)
	  ;; The inews program failed.
	  ()
	(nnheader-report 'nnspool "")
	(set-process-sentinel proc 'nnspool-inews-sentinel)
	(with-temp-buffer
	  (set-buffer-multibyte nil)
	  (insert-buffer-substring buf)
	  (encode-coding-region (point-min) (point-max)
				nnspool-file-coding-system)
	  (process-send-region proc (point-min) (point-max)))
	;; We slap a condition-case around this, because the process may
	;; have exited already...
	(ignore-errors
	  (process-send-eof proc))
	t))))



;;; Internal functions.

(defun nnspool-inews-sentinel (proc _status)
  (with-current-buffer (process-buffer proc)
    (goto-char (point-min))
    (if (or (zerop (buffer-size))
	    (search-forward "spooled" nil t))
	(kill-buffer (current-buffer))
      ;; Make status message by folding lines.
      (while (re-search-forward "[ \t\n]+" nil t)
	(replace-match " " t t))
      (nnheader-report 'nnspool "%s" (buffer-string))
      (nnheader-message 5 "nnspool: %s" nnspool-status-string)
      (ding)
      (run-hooks 'nnspool-rejected-article-hook))))

(defun nnspool-retrieve-headers-with-nov (articles &optional fetch-old)
  (if (or gnus-nov-is-evil nnspool-nov-is-evil)
      nil
    (let ((nov (nnheader-group-pathname
		nnspool-current-group nnspool-nov-directory ".overview"))
	  (arts articles)
	  (nnheader-file-coding-system nnspool-file-coding-system)
	  last)
      (if (not (file-exists-p nov))
	  ()
	(with-current-buffer nntp-server-buffer
	  (erase-buffer)
	  (if nnspool-sift-nov-with-sed
	      (nnspool-sift-nov-with-sed articles nov)
	    (nnheader-insert-file-contents nov)
	    (if (and fetch-old
		     (not (numberp fetch-old)))
		t			; We want all the headers.
	      (ignore-errors
		;; Delete unwanted NOV lines.
		(nnheader-nov-delete-outside-range
		 (if fetch-old (max 1 (- (car articles) fetch-old))
		   (car articles))
		 (car (last articles)))
		;; If the buffer is empty, this wasn't very successful.
		(unless (zerop (buffer-size))
		  ;; We check what the last article number was.
		  ;; The NOV file may be out of sync with the articles
		  ;; in the group.
		  (forward-line -1)
		  (setq last (read (current-buffer)))
		  (if (= last (car articles))
		      ;; Yup, it's all there.
		      t
		    ;; Perhaps not.  We try to find the missing articles.
		    (while (and arts
				(<= last (car arts)))
		      (pop arts))
		    ;; The articles in `arts' are missing from the buffer.
		    (mapc #'nnspool-insert-nov-head arts)
		    t))))))))))

(defun nnspool-insert-nov-head (article)
  "Read the head of ARTICLE, convert to NOV headers, and insert."
  (save-excursion
    (let ((cur (current-buffer))
          buf)
      (setq buf (nnheader-set-temp-buffer " *nnspool head*"))
      (when (nnheader-insert-head
             (nnspool-article-pathname nnspool-current-group article))
        (nnheader-insert-article-line article)
        (goto-char (point-min))
        (let ((headers (nnheader-parse-head nil t)))
          (set-buffer cur)
          (goto-char (point-max))
          (nnheader-insert-nov headers)))
      (kill-buffer buf))))

(defun nnspool-sift-nov-with-sed (articles file)
  (let ((first (car articles))
	(last (car (last articles))))
    (call-process "awk" nil t nil
		  (format "BEGIN {firstmsg=%d; lastmsg=%d;}\n $1 >= firstmsg && $1 <= lastmsg {print;}"
			  (1- first) (1+ last))
		  file)))

;; Fixed by fdc@cliwe.ping.de (Frank D. Cringle).
;; Find out what group an article identified by a Message-ID is in.
(defun nnspool-find-id (id)
  (with-temp-buffer
    (ignore-errors
      (call-process "grep" nil t nil (regexp-quote id) nnspool-history-file))
    (goto-char (point-min))
    (when (looking-at "<[^>]+>[ \t]+[-0-9~]+[ \t]+\\([^ /\t\n]+\\)/\\([0-9]+\\)[ \t\n]")
      (cons (match-string 1) (string-to-number (match-string 2))))))

(defun nnspool-find-file (file)
  "Insert FILE in server buffer safely."
  (set-buffer nntp-server-buffer)
  (erase-buffer)
  (condition-case ()
      (let ((coding-system-for-read nnspool-file-coding-system))
	(mm-insert-file-contents file)
	t)
    (file-error nil)))

(defun nnspool-possibly-change-directory (group)
  (if (not group)
      t
    (let ((pathname (nnspool-article-pathname group)))
      (if (file-directory-p pathname)
	  (setq nnspool-current-directory pathname
		nnspool-current-group group)
	(nnheader-report 'nnspool "No such newsgroup: %s" group)))))

(defun nnspool-article-pathname (group &optional article)
  "Find the file name for GROUP."
  (nnheader-group-pathname group nnspool-spool-directory article))

(provide 'nnspool)

;;; nnspool.el ends here