bug#15808: 24.3; thing-at-point slow for url and email

[Leo Liu]

On 2013-11-06 10:18 +0800, Stefan Monnier wrote:
> The count is too small: this is a sample-based profiler, so you need
> a long enough runtime to get meaningful results (otherwise, the various
> stack fragments collected can't be pieced together to get the whole tree).
>
> Also, it seems some of the code is interpreted.  If the result is still
> hard to interpret, you might want to try and byte-compile that code.

I tried the thingatpt.el and the URL case is not slow there but email
is. Profiler says most time is spent in thing-at-point-looking-at. I
propose the following fix? Comments?

=== modified file 'lisp/thingatpt.el'
--- lisp/thingatpt.el   2013-08-10 15:17:29 +0000
+++ lisp/thingatpt.el   2013-11-06 03:32:52 +0000
@@ -476,7 +476,7 @@
 ;; matches that straddle the start position so we search forwards once
 ;; and then back repeatedly and then back up a char at a time.
 
-(defun thing-at-point-looking-at (regexp)
+(defun thing-at-point-looking-at (regexp &optional limit)
   "Return non-nil if point is in or just after a match for REGEXP.
 Set the match data from the earliest such match ending at or after
 point."
@@ -487,7 +487,7 @@
           (setq match (point)))
       ;; Search back repeatedly from end of next match.
       ;; This may fail if next match ends before this match does.
-      (re-search-forward regexp nil 'limit)
+      (re-search-forward regexp limit 'limit)
       (while (and (re-search-backward regexp nil t)
                  (or (> (match-beginning 0) old-point)
                      (and (looking-at regexp)  ; Extend match-end past search 
start
@@ -518,7 +518,8 @@
 
 (put 'email 'bounds-of-thing-at-point
      (lambda ()
-       (let ((thing (thing-at-point-looking-at thing-at-point-email-regexp)))
+       (let ((thing (thing-at-point-looking-at thing-at-point-email-regexp
+                                              (+ (point) 500))))
          (if thing
              (let ((beginning (match-beginning 0))
                    (end (match-end 0)))