From: yamaoka <yamaoka>
Date: Tue, 5 Dec 2000 07:32:57 +0000 (+0000)
Subject: Synch with Gnus.
X-Git-Url: http://git.chise.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a030bf50289db8cea8c8200dbad11775ed2a468e;p=elisp%2Fgnus.git-

Synch with Gnus.
---

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 79c9931..22d1e25 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,66 @@
+2000-12-04 22:00:00  ShengHuo ZHU  <zsh@cs.rochester.edu>
+
+	* gnus-win.el (gnus-configure-frame): Save selected window.
+
+2000-02-15  Andrew Innes  <andrewi@gnu.org>
+
+	* nnmbox.el: Require gnus-range.
+	(nnmbox-group-building-active-articles): New variable.
+	(nnmbox-group-active-articles): New variable; this is a cache of
+	all active articles by group and number.
+	(nnmbox-in-header-p): New function.
+	(nnmbox-find-article): New function.
+	(nnmbox-record-active-article): New function.
+	(nnmbox-record-deleted-article): New function.
+	(nnmbox-is-article-active-p): New function.
+	(nnmbox-retrieve-headers): Use nnmbox-find-article.
+	(nnmbox-request-article): Ditto.  Also supply extra arg to
+	nnmbox-article-group-number.
+	(nnmbox-request-expire-articles): Ditto.
+	(nnmbox-request-move-article): Ditto.
+	(nnmbox-request-replace-article): Ditto.
+	(nnmbox-request-rename-group): Rename group entry in active
+	article cache.
+	(nnmbox-delete-mail): Update active article cache, unless article
+	is being replaced.
+	(nnmbox-possibly-change-newsgroup): Call nnmbox-read-mbox, rather
+	than partially duplicating it.
+	(nnmbox-article-group-number): Add extra `this-line' arg, to
+	handle articles belonging to multiple groups.
+	(nnmbox-save-mail): Update active article cache.
+	(nnmbox-read-mbox): Build active article cache when loading mbox.
+	Also do some repair work, if we find articles that are missing the
+	appropriate X-Gnus-Newsgroup lines in the header.  We can usually
+	reconstruct these from Xref info.
+	
+2000-12-04 18:00:00  ShengHuo ZHU  <zsh@cs.rochester.edu>
+
+	* mail-source.el (mail-source-report-new-mail): Use
+	nnheader-run-at-time.
+
+2000-02-15  Andrew Innes  <andrewi@gnu.org>
+
+	* mail-source.el (mail-source-fetch-pop): Clear pop password when
+	an error is thrown, and then rethrow the error.
+	(mail-source-check-pop): Ditto.
+	(mail-source-start-idle-timer): Prevent multiple pop checks
+	running if the check takes a long time.
+	
+2000-12-04 14:00:00  ShengHuo ZHU  <zsh@cs.rochester.edu>
+
+	* gnus-msg.el (gnus-msg-mail): COMPOSEFUNC should return t if
+	succeed.
+
+2000-12-04 13:00:00  ShengHuo ZHU  <zsh@cs.rochester.edu>
+
+	* gnus-win.el (gnus-configure-windows): Make sure
+	nntp-server-buffer is live.
+	(gnus-remove-some-windows): switch-to-buffer -> set-buffer.
+
+2000-11-21  Stefan Monnier  <monnier@cs.yale.edu>
+
+	* gnus-win.el (gnus-configure-windows): switch-to-buffer -> set-buffer.
+
 2000-12-04  Andreas Jaeger  <aj@suse.de>
 
 	* gnus-msg.el (gnus-summary-mail-forward): Fix typos in description.
diff --git a/lisp/gnus-msg.el b/lisp/gnus-msg.el
index e7d658f..e5ca6ec 100644
--- a/lisp/gnus-msg.el
+++ b/lisp/gnus-msg.el
@@ -259,10 +259,12 @@ Thank you for your help in stamping out bugs.
 (defun gnus-msg-mail (&rest args)
   "Start editing a mail message to be sent.
 Like `message-mail', but with Gnus paraphernalia, particularly the
-the Gcc: header for archiving purposes."
+Gcc: header for archiving purposes."
   (interactive)
   (gnus-setup-message 'message
-    (apply 'message-mail args)))
+    (apply 'message-mail args))
+  ;; COMPOSEFUNC should return t if succeed.  Undocumented ???
+  t)
 
 ;;;###autoload
 (define-mail-user-agent 'gnus-user-agent
diff --git a/lisp/gnus-win.el b/lisp/gnus-win.el
index 6a9ce29..51934fd 100644
--- a/lisp/gnus-win.el
+++ b/lisp/gnus-win.el
@@ -286,127 +286,128 @@ See the Gnus manual for an explanation of the syntax used.")
 
 (defun gnus-configure-frame (split &optional window)
   "Split WINDOW according to SPLIT."
-  (unless window
-    (setq window (or (get-buffer-window (current-buffer)) (selected-window))))
-  (select-window window)
-  ;; This might be an old-stylee buffer config.
-  (when (vectorp split)
-    (setq split (append split nil)))
-  (when (or (consp (car split))
-	    (vectorp (car split)))
-    (push 1.0 split)
-    (push 'vertical split))
-  ;; The SPLIT might be something that is to be evaled to
-  ;; return a new SPLIT.
-  (while (and (not (assq (car split) gnus-window-to-buffer))
-	      (gnus-functionp (car split)))
-    (setq split (eval split)))
-  (let* ((type (car split))
-	 (subs (cddr split))
-	 (len (if (eq type 'horizontal) (window-width) (window-height)))
-	 (total 0)
-	 (window-min-width (or gnus-window-min-width window-min-width))
-	 (window-min-height (or gnus-window-min-height window-min-height))
-	 s result new-win rest comp-subs size sub)
-    (cond
-     ;; Nothing to do here.
-     ((null split))
-     ;; Don't switch buffers.
-     ((null type)
-      (and (memq 'point split) window))
-     ;; This is a buffer to be selected.
-     ((not (memq type '(frame horizontal vertical)))
-      (let ((buffer (cond ((stringp type) type)
-			  (t (cdr (assq type gnus-window-to-buffer))))))
-	(unless buffer
-	  (error "Invalid buffer type: %s" type))
-	(let ((buf (gnus-get-buffer-create
- 		    (gnus-window-to-buffer-helper buffer))))
- 	  (if (eq buf (window-buffer (selected-window))) (set-buffer buf)
- 	    (switch-to-buffer buf)))
-	(when (memq 'frame-focus split)
-	  (setq gnus-window-frame-focus window))
-	;; We return the window if it has the `point' spec.
-	(and (memq 'point split) window)))
-     ;; This is a frame split.
-     ((eq type 'frame)
-      (unless gnus-frame-list
-	(setq gnus-frame-list (list (window-frame
-				     (get-buffer-window (current-buffer))))))
-      (let ((i 0)
-	    params frame fresult)
-	(while (< i (length subs))
-	  ;; Frame parameter is gotten from the sub-split.
-	  (setq params (cadr (elt subs i)))
-	  ;; It should be a list.
-	  (unless (listp params)
-	    (setq params nil))
-	  ;; Create a new frame?
-	  (unless (setq frame (elt gnus-frame-list i))
-	    (nconc gnus-frame-list (list (setq frame (make-frame params))))
-	    (push frame gnus-created-frames))
-	  ;; Is the old frame still alive?
-	  (unless (frame-live-p frame)
-	    (setcar (nthcdr i gnus-frame-list)
-		    (setq frame (make-frame params))))
-	  ;; Select the frame in question and do more splits there.
-	  (select-frame frame)
-	  (setq fresult (or (gnus-configure-frame (elt subs i)) fresult))
-	  (incf i))
-	;; Select the frame that has the selected buffer.
-	(when fresult
-	  (select-frame (window-frame fresult)))))
-     ;; This is a normal split.
-     (t
-      (when (> (length subs) 0)
-	;; First we have to compute the sizes of all new windows.
-	(while subs
-	  (setq sub (append (pop subs) nil))
-	  (while (and (not (assq (car sub) gnus-window-to-buffer))
-		      (gnus-functionp (car sub)))
-	    (setq sub (eval sub)))
-	  (when sub
-	    (push sub comp-subs)
-	    (setq size (cadar comp-subs))
-	    (cond ((equal size 1.0)
-		   (setq rest (car comp-subs))
-		   (setq s 0))
-		  ((floatp size)
-		   (setq s (floor (* size len))))
-		  ((integerp size)
-		   (setq s size))
-		  (t
-		   (error "Invalid size: %s" size)))
-	    ;; Try to make sure that we are inside the safe limits.
-	    (cond ((zerop s))
-		  ((eq type 'horizontal)
-		   (setq s (max s window-min-width)))
-		  ((eq type 'vertical)
-		   (setq s (max s window-min-height))))
-	    (setcar (cdar comp-subs) s)
-	    (incf total s)))
-	;; Take care of the "1.0" spec.
-	(if rest
-	    (setcar (cdr rest) (- len total))
-	  (error "No 1.0 specs in %s" split))
-	;; The we do the actual splitting in a nice recursive
-	;; fashion.
-	(setq comp-subs (nreverse comp-subs))
-	(while comp-subs
-	  (if (null (cdr comp-subs))
-	      (setq new-win window)
-	    (setq new-win
-		  (split-window window (cadar comp-subs)
-				(eq type 'horizontal))))
-	  (setq result (or (gnus-configure-frame
-			    (car comp-subs) window)
-			   result))
-	  (select-window new-win)
-	  (setq window new-win)
-	  (setq comp-subs (cdr comp-subs))))
-      ;; Return the proper window, if any.
-      (when result
-	(select-window result))))))
+  (let ((current-window
+	 (or (get-buffer-window (current-buffer)) (selected-window))))
+    (unless window
+      (setq window current-window))
+    (select-window window)
+    ;; This might be an old-stylee buffer config.
+    (when (vectorp split)
+      (setq split (append split nil)))
+    (when (or (consp (car split))
+	      (vectorp (car split)))
+      (push 1.0 split)
+      (push 'vertical split))
+    ;; The SPLIT might be something that is to be evaled to
+    ;; return a new SPLIT.
+    (while (and (not (assq (car split) gnus-window-to-buffer))
+		(gnus-functionp (car split)))
+      (setq split (eval split)))
+    (let* ((type (car split))
+	   (subs (cddr split))
+	   (len (if (eq type 'horizontal) (window-width) (window-height)))
+	   (total 0)
+	   (window-min-width (or gnus-window-min-width window-min-width))
+	   (window-min-height (or gnus-window-min-height window-min-height))
+	   s result new-win rest comp-subs size sub)
+      (cond
+       ;; Nothing to do here.
+       ((null split))
+       ;; Don't switch buffers.
+       ((null type)
+	(and (memq 'point split) window))
+       ;; This is a buffer to be selected.
+       ((not (memq type '(frame horizontal vertical)))
+	(let ((buffer (cond ((stringp type) type)
+			    (t (cdr (assq type gnus-window-to-buffer))))))
+	  (unless buffer
+	    (error "Invalid buffer type: %s" type))
+	  (let ((buf (gnus-get-buffer-create
+		      (gnus-window-to-buffer-helper buffer))))
+	    (if (eq buf (window-buffer (selected-window))) (set-buffer buf)
+	      (switch-to-buffer buf)))
+	  (when (memq 'frame-focus split)
+	    (setq gnus-window-frame-focus window))
+	  ;; We return the window if it has the `point' spec.
+	  (and (memq 'point split) window)))
+       ;; This is a frame split.
+       ((eq type 'frame)
+	(unless gnus-frame-list
+	  (setq gnus-frame-list (list (window-frame current-window))))
+	(let ((i 0)
+	      params frame fresult)
+	  (while (< i (length subs))
+	    ;; Frame parameter is gotten from the sub-split.
+	    (setq params (cadr (elt subs i)))
+	    ;; It should be a list.
+	    (unless (listp params)
+	      (setq params nil))
+	    ;; Create a new frame?
+	    (unless (setq frame (elt gnus-frame-list i))
+	      (nconc gnus-frame-list (list (setq frame (make-frame params))))
+	      (push frame gnus-created-frames))
+	    ;; Is the old frame still alive?
+	    (unless (frame-live-p frame)
+	      (setcar (nthcdr i gnus-frame-list)
+		      (setq frame (make-frame params))))
+	    ;; Select the frame in question and do more splits there.
+	    (select-frame frame)
+	    (setq fresult (or (gnus-configure-frame (elt subs i)) fresult))
+	    (incf i))
+	  ;; Select the frame that has the selected buffer.
+	  (when fresult
+	    (select-frame (window-frame fresult)))))
+       ;; This is a normal split.
+       (t
+	(when (> (length subs) 0)
+	  ;; First we have to compute the sizes of all new windows.
+	  (while subs
+	    (setq sub (append (pop subs) nil))
+	    (while (and (not (assq (car sub) gnus-window-to-buffer))
+			(gnus-functionp (car sub)))
+	      (setq sub (eval sub)))
+	    (when sub
+	      (push sub comp-subs)
+	      (setq size (cadar comp-subs))
+	      (cond ((equal size 1.0)
+		     (setq rest (car comp-subs))
+		     (setq s 0))
+		    ((floatp size)
+		     (setq s (floor (* size len))))
+		    ((integerp size)
+		     (setq s size))
+		    (t
+		     (error "Invalid size: %s" size)))
+	      ;; Try to make sure that we are inside the safe limits.
+	      (cond ((zerop s))
+		    ((eq type 'horizontal)
+		     (setq s (max s window-min-width)))
+		    ((eq type 'vertical)
+		     (setq s (max s window-min-height))))
+	      (setcar (cdar comp-subs) s)
+	      (incf total s)))
+	  ;; Take care of the "1.0" spec.
+	  (if rest
+	      (setcar (cdr rest) (- len total))
+	    (error "No 1.0 specs in %s" split))
+	  ;; The we do the actual splitting in a nice recursive
+	  ;; fashion.
+	  (setq comp-subs (nreverse comp-subs))
+	  (while comp-subs
+	    (if (null (cdr comp-subs))
+		(setq new-win window)
+	      (setq new-win
+		    (split-window window (cadar comp-subs)
+				  (eq type 'horizontal))))
+	    (setq result (or (gnus-configure-frame
+			      (car comp-subs) window)
+			     result))
+	    (select-window new-win)
+	    (setq window new-win)
+	    (setq comp-subs (cdr comp-subs))))
+	;; Return the proper window, if any.
+	(when result
+	  (select-window result)))))))
 
 (defvar gnus-frame-split-p nil)
 
@@ -432,6 +433,10 @@ See the Gnus manual for an explanation of the syntax used.")
 	  ;; put point in the assigned buffer, and do not touch the
 	  ;; winconf.
 	  (select-window all-visible)
+	
+	;; Make sure "the other" buffer, nntp-server-buffer, is live.
+	(unless (gnus-buffer-live-p nntp-server-buffer)
+	  (nnheader-init-server-buffer))
 
 	;; Either remove all windows or just remove all Gnus windows.
 	(let ((frame (selected-frame)))
@@ -447,11 +452,11 @@ See the Gnus manual for an explanation of the syntax used.")
 		    (gnus-delete-windows-in-gnusey-frames))
 		;; Just remove some windows.
 		(gnus-remove-some-windows)
-		(switch-to-buffer nntp-server-buffer))
+		(set-buffer nntp-server-buffer))
 	    (select-frame frame)))
 
 	(let (gnus-window-frame-focus)
-	  (switch-to-buffer nntp-server-buffer)
+	  (set-buffer nntp-server-buffer)
 	  (gnus-configure-frame split)
 	  (when gnus-window-frame-focus
 	    (select-frame (window-frame gnus-window-frame-focus))))))))
@@ -536,7 +541,7 @@ should have point."
 		  lowest-buf buf))))
       (when lowest-buf
 	(pop-to-buffer lowest-buf)
-	(switch-to-buffer nntp-server-buffer))
+	(set-buffer nntp-server-buffer))
       (mapcar (lambda (b) (delete-windows-on b t)) bufs))))
 
 (provide 'gnus-win)
diff --git a/lisp/mail-source.el b/lisp/mail-source.el
index 816177b..71a73a3 100644
--- a/lisp/mail-source.el
+++ b/lisp/mail-source.el
@@ -33,7 +33,8 @@
   (defvar pop3-leave-mail-on-server)
   (autoload 'pop3-movemail "pop3")
   (autoload 'pop3-get-message-count "pop3")
-  (autoload 'nnheader-cancel-timer "nnheader"))
+  (autoload 'nnheader-cancel-timer "nnheader")
+  (autoload 'nnheader-run-at-time "nnheader"))
 (require 'format-spec)
 
 (defgroup mail-source nil
@@ -662,7 +663,15 @@ If ARGS, PROMPT is used as an argument to `format'."
 		     (or leave
 			 (and (boundp 'pop3-leave-mail-on-server)
 			      pop3-leave-mail-on-server))))
-		(save-excursion (pop3-movemail mail-source-crash-box))))))
+		(condition-case err
+		    (save-excursion (pop3-movemail mail-source-crash-box))
+		  (error
+		   ;; We nix out the password in case the error
+		   ;; was because of a wrong password being given.
+		   (setq mail-source-password-cache
+			 (delq (assoc from mail-source-password-cache)
+			       mail-source-password-cache))
+		   (signal (car err) (cdr err))))))))
       (if result
 	  (progn
 	    (when (eq authentication 'password)
@@ -713,7 +722,15 @@ If ARGS, PROMPT is used as an argument to `format'."
 		    (pop3-port port)
 		    (pop3-authentication-scheme
 		     (if (eq authentication 'apop) 'apop 'pass)))
-		(save-excursion (pop3-get-message-count))))))
+		(condition-case err
+		    (save-excursion (pop3-get-message-count))
+		  (error
+		   ;; We nix out the password in case the error
+		   ;; was because of a wrong password being given.
+		   (setq mail-source-password-cache
+			 (delq (assoc from mail-source-password-cache)
+			       mail-source-password-cache))
+		   (signal (car err) (cdr err))))))))
       (if result
 	  ;; Inform display-time that we have new mail.
 	  (setq mail-source-new-mail-available (> result 0))
@@ -748,8 +765,8 @@ If ARGS, PROMPT is used as an argument to `format'."
 	   mail-source-idle-time-delay
 	   nil
 	   (lambda ()
-	     (setq mail-source-report-new-mail-idle-timer nil)
-	     (mail-source-check-pop mail-source-primary-source))))
+	     (mail-source-check-pop mail-source-primary-source)
+	     (setq mail-source-report-new-mail-idle-timer nil))))
     ;; Since idle timers created when Emacs is already in the idle
     ;; state don't get activated until Emacs _next_ becomes idle, we
     ;; need to force our timer to be considered active now.  We do
@@ -780,8 +797,10 @@ This only works when `display-time' is enabled."
 	  (setq display-time-mail-function #'mail-source-new-mail-p)
 	  ;; Set up the main timer.
 	  (setq mail-source-report-new-mail-timer
-		(run-at-time t (* 60 mail-source-report-new-mail-interval)
-			     #'mail-source-start-idle-timer))
+		(nnheader-run-at-time
+		 (* 60 mail-source-report-new-mail-interval)
+		 (* 60 mail-source-report-new-mail-interval)
+		 #'mail-source-start-idle-timer))
 	  ;; When you get new mail, clear "Mail" from the mode line.
 	  (add-hook 'nnmail-post-get-new-mail-hook
 		    'display-time-event-handler)
diff --git a/lisp/nnmbox.el b/lisp/nnmbox.el
index a064c93..02bcbef 100644
--- a/lisp/nnmbox.el
+++ b/lisp/nnmbox.el
@@ -31,6 +31,7 @@
 (require 'message)
 (require 'nnmail)
 (require 'nnoo)
+(require 'gnus-range)
 
 (nnoo-declare nnmbox)
 
@@ -66,6 +67,8 @@
 (defvoo nnmbox-active-file-coding-system nnheader-text-coding-system)
 (defvoo nnmbox-active-file-coding-system-for-write nil)
 
+(defvar nnmbox-group-building-active-articles nil)
+(defvar nnmbox-group-active-articles nil)
 
 
 ;;; Interface functions
@@ -78,15 +81,12 @@
     (erase-buffer)
     (let ((number (length sequence))
 	  (count 0)
-	  article art-string start stop)
+	  article start stop)
       (nnmbox-possibly-change-newsgroup newsgroup server)
       (while sequence
 	(setq article (car sequence))
-	(setq art-string (nnmbox-article-string article))
 	(set-buffer nnmbox-mbox-buffer)
-	(when (or (search-forward art-string nil t)
-		  (progn (goto-char (point-min))
-			 (search-forward art-string nil t)))
+	(when (nnmbox-find-article article)
 	  (setq start
 		(save-excursion
 		  (re-search-backward
@@ -148,8 +148,7 @@
   (nnmbox-possibly-change-newsgroup newsgroup server)
   (save-excursion
     (set-buffer nnmbox-mbox-buffer)
-    (goto-char (point-min))
-    (when (search-forward (nnmbox-article-string article) nil t)
+    (when (nnmbox-find-article article)
       (let (start stop)
 	(re-search-backward (concat "^" message-unix-mail-delimiter) nil t)
 	(setq start (point))
@@ -170,7 +169,7 @@
 	    (forward-line 1))
 	  (if (numberp article)
 	      (cons nnmbox-current-group article)
-	    (nnmbox-article-group-number)))))))
+	    (nnmbox-article-group-number nil)))))))
 
 (deffoo nnmbox-request-group (group &optional server dont-check)
   (nnmbox-possibly-change-newsgroup nil server)
@@ -261,8 +260,7 @@
     (save-excursion
       (set-buffer nnmbox-mbox-buffer)
       (while (and articles is-old)
-	(goto-char (point-min))
-	(when (search-forward (nnmbox-article-string (car articles)) nil t)
+	(when (nnmbox-find-article (car articles))
 	  (if (setq is-old
 		    (nnmail-expired-article-p
 		     newsgroup
@@ -285,12 +283,9 @@
       (nnmbox-save-buffer)
       ;; Find the lowest active article in this group.
       (let ((active (nth 1 (assoc newsgroup nnmbox-group-alist))))
-	(goto-char (point-min))
-	(while (and (not (search-forward
-			  (nnmbox-article-string (car active)) nil t))
+	(while (and (not (nnmbox-find-article (car active)))
 		    (<= (car active) (cdr active)))
-	  (setcar active (1+ (car active)))
-	  (goto-char (point-min))))
+	  (setcar active (1+ (car active)))))
       (nnmbox-save-active nnmbox-group-alist nnmbox-active-file)
       (nconc rest articles))))
 
@@ -316,8 +311,7 @@
      (save-excursion
        (nnmbox-possibly-change-newsgroup group server)
        (set-buffer nnmbox-mbox-buffer)
-       (goto-char (point-min))
-       (when (search-forward (nnmbox-article-string article) nil t)
+       (when (nnmbox-find-article article)
 	 (nnmbox-delete-mail))
        (and last (nnmbox-save-buffer))))
     result))
@@ -367,8 +361,7 @@
   (nnmbox-possibly-change-newsgroup group)
   (save-excursion
     (set-buffer nnmbox-mbox-buffer)
-    (goto-char (point-min))
-    (if (not (search-forward (nnmbox-article-string article) nil t))
+    (if (not (nnmbox-find-article article))
 	nil
       (nnmbox-delete-mail t t)
       (insert-buffer-substring buffer)
@@ -412,6 +405,9 @@
 	(setq found t))
       (when found
 	(nnmbox-save-buffer))))
+  (let ((entry (assoc group nnmbox-group-active-articles)))
+    (when entry
+      (setcar entry new-name)))
   (let ((entry (assoc group nnmbox-group-alist)))
     (when entry
       (setcar entry new-name))
@@ -428,6 +424,10 @@
 ;; delimiter line.
 (defun nnmbox-delete-mail (&optional force leave-delim)
   ;; Delete the current X-Gnus-Newsgroup line.
+  ;; First delete record of active article, unless the article is being
+  ;; replaced, indicated by FORCE being non-nil.
+  (if (not force)
+      (nnmbox-record-deleted-article (nnmbox-article-group-number t)))
   (or force
       (delete-region
        (progn (beginning-of-line) (point))
@@ -449,7 +449,7 @@
 		    (match-beginning 0)))
 	     (point-max))))
       (goto-char (point-min))
-      ;; Only delete the article if no other groups owns it as well.
+      ;; Only delete the article if no other group owns it as well.
       (when (or force (not (re-search-forward "^X-Gnus-Newsgroup: " nil t)))
 	(delete-region (point-min) (point-max))))))
 
@@ -459,13 +459,7 @@
     (nnmbox-open-server server))
   (when (or (not nnmbox-mbox-buffer)
 	    (not (buffer-name nnmbox-mbox-buffer)))
-    (save-excursion
-      (set-buffer (setq nnmbox-mbox-buffer
-			(let ((nnheader-file-coding-system
-			       nnmbox-file-coding-system))
-			  (nnheader-find-file-noselect
-			   nnmbox-mbox-file nil t))))
-      (buffer-disable-undo)))
+    (nnmbox-read-mbox))
   (when (not nnmbox-group-alist)
     (nnmail-activate 'nnmbox))
   (if newsgroup
@@ -479,15 +473,86 @@
 	      (int-to-string article) " ")
     (concat "\nMessage-ID: " article)))
 
-(defun nnmbox-article-group-number ()
+(defun nnmbox-article-group-number (this-line)
   (save-excursion
-    (goto-char (point-min))
+    (if this-line
+	(beginning-of-line)
+      (goto-char (point-min)))
     (when (re-search-forward "^X-Gnus-Newsgroup: +\\([^:]+\\):\\([0-9]+\\) "
 			     nil t)
       (cons (buffer-substring (match-beginning 1) (match-end 1))
 	    (string-to-int
 	     (buffer-substring (match-beginning 2) (match-end 2)))))))
 
+(defun nnmbox-in-header-p (pos)
+  "Return non-nil if POS is in the header of an article."
+  (save-excursion
+    (goto-char pos)
+    (re-search-backward (concat "^" message-unix-mail-delimiter) nil t)
+    (search-forward "\n\n" nil t)
+    (< pos (point))))
+
+(defun nnmbox-find-article (article)
+  "Leaves point on the relevant X-Gnus-Newsgroup line if found."
+  ;; Check that article is in the active range first, to avoid an
+  ;; expensive exhaustive search if it isn't.
+  (if (and (numberp article)
+	   (not (nnmbox-is-article-active-p article)))
+      nil
+    (let ((art-string (nnmbox-article-string article))
+	  (found nil))
+      ;; There is the possibility that the X-Gnus-Newsgroup line appears
+      ;; in the body of an article (for instance, if an article has been
+      ;; forwarded from someone using Gnus as their mailer), so check
+      ;; that the line is actually part of the article header.
+      (or (and (search-forward art-string nil t)
+	       (nnmbox-in-header-p (point)))
+	  (progn
+	    (goto-char (point-min))
+	    (while (not found)
+	      (setq found (and (search-forward art-string nil t)
+			       (nnmbox-in-header-p (point)))))
+	    found)))))
+
+(defun nnmbox-record-active-article (group-art)
+  (let* ((group (car group-art))
+	 (article (cdr group-art))
+	 (entry
+	  (or (assoc group nnmbox-group-active-articles)
+	      (progn
+		(push (list group)
+		      nnmbox-group-active-articles)
+		(car nnmbox-group-active-articles)))))
+    ;; add article to index, either by building complete list
+    ;; in reverse order, or as a list of ranges.
+    (if (not nnmbox-group-building-active-articles)
+	(setcdr entry (gnus-add-to-range (cdr entry) (list article)))
+      (when (memq article (cdr entry))
+	(switch-to-buffer nnmbox-mbox-buffer)
+	(error "Article %s:%d already exists!" group article))
+      (when (and (cadr entry) (< article (cadr entry)))
+	(switch-to-buffer nnmbox-mbox-buffer)
+	(error "Article %s:%d out of order" group article))
+      (setcdr entry (cons article (cdr entry))))))
+
+(defun nnmbox-record-deleted-article (group-art)
+  (let* ((group (car group-art))
+	 (article (cdr group-art))
+	 (entry
+	  (or (assoc group nnmbox-group-active-articles)
+	      (progn
+		(push (list group)
+		      nnmbox-group-active-articles)
+		(car nnmbox-group-active-articles)))))
+    ;; remove article from index
+    (setcdr entry (gnus-remove-from-range (cdr entry) (list article)))))
+
+(defun nnmbox-is-article-active-p (article)
+  (gnus-member-of-range
+   article
+   (cdr (assoc nnmbox-current-group
+	       nnmbox-group-active-articles))))
+
 (defun nnmbox-save-mail (group-art)
   "Called narrowed to an article."
   (let ((delim (concat "^" message-unix-mail-delimiter)))
@@ -504,6 +569,10 @@
     (nnmail-insert-lines)
     (nnmail-insert-xref group-art)
     (nnmbox-insert-newsgroup-line group-art)
+    (let ((alist group-art))
+      (while alist
+	(nnmbox-record-active-article (car alist))
+	(setq alist (cdr alist))))
     (run-hooks 'nnmail-prepare-save-mail-hook)
     (run-hooks 'nnmbox-prepare-save-mail-hook)
     group-art))
@@ -551,7 +620,8 @@
     (save-excursion
       (let ((delim (concat "^" message-unix-mail-delimiter))
 	    (alist nnmbox-group-alist)
-	    start end number)
+	    (nnmbox-group-building-active-articles t)
+	    start end end-header number)
 	(set-buffer (setq nnmbox-mbox-buffer
 			  (let ((nnheader-file-coding-system
 				 nnmbox-file-coding-system))
@@ -559,8 +629,7 @@
 			     nnmbox-mbox-file nil t))))
  	(buffer-disable-undo)
 
-	;; Go through the group alist and compare against
-	;; the mbox file.
+	;; Go through the group alist and compare against the mbox file.
 	(while alist
 	  (goto-char (point-max))
 	  (when (and (re-search-backward
@@ -574,29 +643,57 @@
 	    (setcdr (cadar alist) number))
 	  (setq alist (cdr alist)))
 
+	;; Examine all articles for our private X-Gnus-Newsgroup
+	;; headers.  This is done primarily as a consistency check, but
+	;; it is convenient for building an index of the articles
+	;; present, to avoid costly searches for missing articles
+	;; (eg. when expiring articles).
 	(goto-char (point-min))
+	(setq nnmbox-group-active-articles nil)
 	(while (re-search-forward delim nil t)
 	  (setq start (match-beginning 0))
-	  (unless (search-forward
-		   "\nX-Gnus-Newsgroup: "
-		   (save-excursion
-		     (setq end
-			   (or
-			    (and
-			     ;; skip to end of headers first, since mail
-			     ;; which has been respooled has additional
-			     ;; "From nobody" lines.
-			     (search-forward "\n\n" nil t)
-			     (re-search-forward delim nil t)
-			     (match-beginning 0))
-			    (point-max))))
-		   t)
+	  (save-excursion
+	    (search-forward "\n\n" nil t)
+	    (setq end-header (point))
+	    (setq end (or (and
+			   (re-search-forward delim nil t)
+			   (match-beginning 0))
+			  (point-max))))
+	  (if (search-forward "\nX-Gnus-Newsgroup: " end-header t)
+	      ;; Build a list of articles in each group, remembering
+	      ;; that each article may be in more than one group.
+	      (progn
+		(nnmbox-record-active-article (nnmbox-article-group-number t))
+		(while (search-forward "\nX-Gnus-Newsgroup: " end-header t)
+		  (nnmbox-record-active-article (nnmbox-article-group-number t))))
+	    ;; The article is either new, or for some other reason
+	    ;; hasn't got our private headers, so add them now.  The
+	    ;; only situation I've encountered when the X-Gnus-Newsgroup
+	    ;; header is missing is if the article contains a forwarded
+	    ;; message which does contain that header line (earlier
+	    ;; versions of Gnus didn't restrict their search to the
+	    ;; headers).  In this case, there is an Xref line which
+	    ;; provides the relevant information to construct the
+	    ;; missing header(s).
 	    (save-excursion
 	      (save-restriction
 		(narrow-to-region start end)
-		(nnmbox-save-mail
-		 (nnmail-article-group 'nnmbox-active-number)))))
-	  (goto-char end))))))
+		(if (re-search-forward "\nXref: [^ ]+" end-header t)
+		    ;; generate headers from Xref:
+		    (let (alist)
+		      (while (re-search-forward " \\([^:]+\\):\\([0-9]+\\)" end-header t)
+			(push (cons (match-string 1)
+				    (string-to-int (match-string 2))) alist))
+		      (nnmbox-insert-newsgroup-line alist))
+		  ;; this is really a new article
+		  (nnmbox-save-mail
+		   (nnmail-article-group 'nnmbox-active-number))))))
+	  (goto-char end))
+	;; put article lists in order
+	(setq alist nnmbox-group-active-articles)
+	(while alist
+	  (setcdr (car alist) (gnus-compress-sequence (nreverse (cdar alist))))
+	  (setq alist (cdr alist)))))))
 
 (provide 'nnmbox)