with-case-table / ascii-case-table (was: [yazicivo@ttnet.net.tr: Locale Dependent Downcasing in smtpmail])

[Reiner Steib <reinersteib+gmane@imap.cc>]

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On Tue, Apr 03 2007, Chong Yidong wrote:

> How about the following approach?  At the beginning of characters.el,
> save the standard case table (which AFAICT hasn't been modified at
> that point), as a variable ascii-case-table.  Then downcase-ascii can
> use it.
[...]
> + (defun downcase-ascii (string)
> +   "Convert ASCII argument to lower case and return that.
> + The argument may be a character or string.  The result has the same type.
> + The argument object is not altered--the value is a copy."
> +   (let ((old-case-table (current-case-table)))
> +     (unwind-protect
> + 	(progn (set-case-table ascii-case-table)
> + 	       (downcase string))
> +       (set-case-table old-case-table))))

Note that the problem is not only the `downcase' function.  So maybe
adding `with-case-table' would be a good idea.

Turkish Gnus user's might still suffer from the "slow search
operations problem" [1] in `gnus/nnfolder.el'.  Based on your previous
patch, I've made a preliminary patch for `nnfolder.el' [2].  I didn't
test it yet (I don't use the nnfolder back end).  It has to be
adjusted to use `ascii-case-table' and some compatibility code for
Emacs 21 (where the downcase problem is not present).

Bye, Reiner.

[1]
,----[ http://thread.gmane.org/gmane.emacs.gnus.general/63925/focus=63979 ]
| From: Reiner Steib
| Subject: Re: Slow operations on buffers of tens of megabytes
| Newsgroups: gmane.emacs.pretest.bugs, gmane.emacs.gnus.general
| Date: 2006-11-13 17:28:58 GMT (19 weeks, 5 days, 3 hours and 34 minutes ago)
| 
| On Thu, Nov 09 2006, Alexandre Oliva wrote:
| 
| > Ultimately, I'm a bit concerned about messing with the case table of
| > an nnfolder buffer for the entire duration of the buffer.  It's hard
| > to tell whether there'd be any less visible fallouts.
| 
| Richard has eliminated the peculiar upcasing dotless-i to I in CVS.
| Does it fix your problem?
| 
| (IIUC, it should fix it _unless_ the user has a Turkish language
| environment.  I.e. Turkish Gnus user's might still suffer from this
| problem.)
| 
| ,----
| | 2006-11-12  Richard Stallman  <rms <at> gnu.org>
| | 
| | 	* language/european.el (turkish-case-conversion-enable)
| | 	(turkish-case-conversion-disable): New functions.
| | 	("Turkish" lang env): Use them.
| | 
| | 	* international/characters.el (case table):
| | 	Do nothing special for i and I.
| `----
`----

[2] 

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--- nnfolder.el	26 Jan 2007 20:41:00 +0100	7.17
+++ nnfolder.el	01 Apr 2007 23:09:26 +0200	
@@ -104,6 +104,39 @@
 (defconst nnfolder-article-marker "X-Gnus-Article-Number: "
   "String used to demarcate what the article number for a message is.")
 
+;; Make sure we're using the standard case table.  In a Turkish locale, the
+;; "i" in "X-Gnus-Article-Number: " makes parsing large nnfolder groups very
+;; slow.
+;; ,----[ http://thread.gmane.org/gmane.emacs.gnus.general/63925/focus=63979 ]
+;; | Subject: Slow operations on buffers of tens of megabytes
+;; | Newsgroups: gmane.emacs.pretest.bugs,gmane.emacs.gnus.general
+;; | Date: 2006-11-13
+;; `----
+(defun nnfolder-search (&optional function string &rest args)
+  "Search for `nnfolder-article-marker' using the standard case table.
+FUNCTION is used for searching.  If STRING is given, it's used
+instead of `nnfolder-article-marker'.  The remaining ARGS are
+passed to the FUNCTION."
+  (let ((old-case-table (current-case-table))
+	point)
+    (unwind-protect
+	(progn
+	  (set-case-table (standard-case-table))
+	  (setq point
+		(apply (cond
+			((fboundp function)
+			 function)
+			(function
+			 'search-backward)
+			(t
+			 'search-forward))
+		       (or string
+			   (concat "\n" nnfolder-article-marker))
+		       args)))
+      (set-case-table old-case-table))
+    ;; Be sure to return what the FUNCTION returned.
+    point))
+
 (defvoo nnfolder-current-group nil)
 (defvoo nnfolder-current-buffer nil)
 (defvoo nnfolder-status-string "")
@@ -198,8 +231,7 @@
 		      ;; as caused by active file bogosity.
 		      (cond
 		       ((bobp))
-		       ((search-backward (concat "\n" nnfolder-article-marker)
-					 nil t)
+		       ((nnfolder-search 'search-backward nil nil t)
 			(goto-char (match-end 0))
 			(setq num (string-to-number
 				   (buffer-substring
@@ -208,8 +240,7 @@
 			(< num article)))
 		      ;; Check that we are before an article with a
 		      ;; higher number.
-		      (search-forward (concat "\n" nnfolder-article-marker)
-				      nil t)
+		      (nnfolder-search 'search-forward nil nil t)
 		      (progn
 			(setq num (string-to-number
 				   (buffer-substring
@@ -284,8 +315,7 @@
 	      (cons nnfolder-current-group article)
 	    (goto-char (point-min))
 	    (cons nnfolder-current-group
-		  (if (search-forward (concat "\n" nnfolder-article-marker)
-				      nil t)
+		  (if (nnfolder-search 'search-forward nil nil t)
 		      (string-to-number (buffer-substring
 				      (point) (point-at-eol)))
 		    -1))))))))
@@ -405,10 +435,9 @@
     (when nnfolder-current-buffer
       (set-buffer nnfolder-current-buffer)
       (goto-char (point-min))
-      (let ((marker (concat "\n" nnfolder-article-marker))
-	    (number "[0-9]+")
+      (let ((number "[0-9]+")
 	    numbers)
-	(while (and (search-forward marker nil t)
+	(while (and (nnfolder-search 'search-forward nil nil t)
 		    (re-search-forward number nil t))
 	  (let ((newnum (string-to-number (match-string 0))))
 	    (if (nnmail-within-headers-p)
@@ -436,8 +465,7 @@
       (while (and maybe-expirable is-old)
 	(goto-char (point-min))
 	(when (and (nnfolder-goto-article (car maybe-expirable))
-		   (search-forward (concat "\n" nnfolder-article-marker)
-				   nil t))
+		   (nnfolder-search 'search-forward nil nil t))
 	  (forward-sexp)
 	  (when (setq is-old
 		      (nnmail-expired-article-p
@@ -480,8 +508,7 @@
 	 (erase-buffer)
 	 (insert-buffer-substring nntp-server-buffer)
 	 (goto-char (point-min))
-	 (while (re-search-forward
-		 (concat "^" nnfolder-article-marker)
+	 (while (nnfolder-search 're-search-forward nil
 		 (save-excursion (and (search-forward "\n\n" nil t) (point)))
 		 t)
 	   (gnus-delete-line))
@@ -523,7 +550,9 @@
 	(if (search-forward "\n\n" nil t)
 	    (forward-line -1)
 	  (goto-char (point-max)))
-	(while (re-search-backward (concat "^" nnfolder-article-marker) nil t)
+	(while (nnfolder-search 're-search-backward
+				(concat "^" nnfolder-article-marker)
+				nil t)
 	  (delete-region (point) (progn (forward-line 1) (point))))
 	(when nnmail-cache-accepted-message-ids
 	  (nnmail-cache-insert (nnmail-fetch-field "message-id") 
@@ -642,13 +671,12 @@
 (defun nnfolder-adjust-min-active (group)
   ;; Find the lowest active article in this group.
   (let* ((active (cadr (assoc group nnfolder-group-alist)))
-	 (marker (concat "\n" nnfolder-article-marker))
 	 (number "[0-9]+")
 	 (activemin (cdr active)))
     (save-excursion
       (set-buffer nnfolder-current-buffer)
       (goto-char (point-min))
-      (while (and (search-forward marker nil t)
+      (while (and (nnfolder-search 'search-forward nil nil t)
 		  (re-search-forward number nil t))
 	(let ((newnum (string-to-number (match-string 0))))
 	  (if (nnmail-within-headers-p)
@@ -788,7 +816,7 @@
       (if (search-forward "\n\n" nil t)
 	  (forward-line -1)
 	(goto-char (point-max)))
-      (while (search-backward (concat "\n" nnfolder-article-marker) nil t)
+      (while (nnfolder-search 'search-backward nil nil t)
 	(delete-region (1+ (point)) (progn (forward-line 2) (point))))
 
       ;; Insert the new newsgroup marker.
@@ -894,7 +922,6 @@
 	(nnmail-activate 'nnfolder)
 	;; Read in the file.
 	(let ((delim "^From ")
-	      (marker (concat "\n" nnfolder-article-marker))
 	      (number "[0-9]+")
 	      (active (or (cadr (assoc group nnfolder-group-alist))
 			  (cons 1 0)))
@@ -928,7 +955,7 @@
 	  (when (or nnfolder-ignore-active-file
 		    novbuf
 		    (< maxid 2))
-	    (while (and (search-forward marker nil t)
+	    (while (and (nnfolder-search 'search-forward nil nil t)
 			(looking-at number))
 	      (setq newnum (string-to-number (match-string 0)))
 	      (when (nnmail-within-headers-p)
@@ -959,7 +986,7 @@
 	  (when (not (or nnfolder-distrust-mbox
 			 (< maxid 2)))
 	    (goto-char (point-max))
-	    (unless (re-search-backward marker nil t)
+	    (unless (nnfolder-search 're-search-backward nil nil t)
 	      (goto-char (point-min)))
 	    ;;(when (nnmail-search-unix-mail-delim)
 	    ;;  (goto-char (point-min)))
@@ -982,7 +1009,7 @@
 				(point)
 			      (point-max)))
 	    (goto-char start)
-	    (when (not (search-forward marker end t))
+	    (when (not (nnfolder-search 'search-forward nil end t))
 	      (narrow-to-region start end)
 	      (nnmail-insert-lines)
 	      (nnfolder-insert-newsgroup-line

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-- 
       ,,,
      (o o)
---ooO-(_)-Ooo---  |  PGP key available  |  http://rsteib.home.pages.de/

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