From 3893991d27719992c4415326bdf02a8730f98e6f Mon Sep 17 00:00:00 2001
From: hobbs <hobbs>
Date: Fri, 3 Dec 2010 22:30:56 +0000
Subject: 	* generic/tclUtil.c (TclReToGlob): add extra check for
 multiple 	inner *s that leads to poor recursive glob matching, defer to 
 original RE instead.  tclbench RE var backtrack.

---
 ChangeLog         | 14 ++++++++++----
 generic/tclUtil.c | 16 ++++++++++++++--
 2 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 135e686..73c01c4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,11 +1,17 @@
+2010-12-03  Jeff Hobbs  <jeffh@ActiveState.com>
+
+	* generic/tclUtil.c (TclReToGlob): add extra check for multiple
+	inner *s that leads to poor recursive glob matching, defer to
+	original RE instead.  tclbench RE var backtrack.
+
 2010-12-03  Jan Nijtmans  <nijtmans@users.sf.net>
 
 	* generic/tclUtil.c:   silence gcc warning when using -Wwrite-strings
 	* generic/tclStrToD.c: silence gcc warning for non-IEEE platforms
-	* win/Makefile.in:     [Patch #3116490] cross-compile Tcl mingw32 on unix
-	* win/tcl.m4           This makes it possible to cross-compile Tcl/Tk for
-	* win/configure.in     Windows (either 32-bit or 64-bit) out-of-the-box
-	* win/configure        on UNIX, using mingw-w64 build tools (If Itcl, tdbc
+	* win/Makefile.in:  [Patch #3116490] cross-compile Tcl mingw32 on unix
+	* win/tcl.m4        This makes it possible to cross-compile Tcl/Tk for
+	* win/configure.in  Windows (either 32-bit or 64-bit) out-of-the-box
+	* win/configure     on UNIX, using mingw-w64 build tools (If Itcl, tdbc
 	and Thread take over the latest tcl.m4, they can do that too).
 
 2010-12-01  Kevin B. Kenny  <kennykb@acm.org>
diff --git a/generic/tclUtil.c b/generic/tclUtil.c
index 3fc1a35..984ba0a 100644
--- a/generic/tclUtil.c
+++ b/generic/tclUtil.c
@@ -11,7 +11,7 @@
  * See the file "license.terms" for information on usage and redistribution of
  * this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tclUtil.c,v 1.122 2010/12/03 09:19:40 nijtmans Exp $
+ * RCS: @(#) $Id: tclUtil.c,v 1.123 2010/12/03 22:30:56 hobbs Exp $
  */
 
 #include "tclInt.h"
@@ -3328,7 +3328,7 @@ TclReToGlob(
     Tcl_DString *dsPtr,
     int *exactPtr)
 {
-    int anchorLeft, anchorRight, lastIsStar;
+    int anchorLeft, anchorRight, lastIsStar, numStars;
     char *dsStr, *dsStrStart;
     const char *msg, *p, *strEnd;
 
@@ -3387,6 +3387,7 @@ TclReToGlob(
     p = reStr;
     anchorRight = 0;
     lastIsStar = 0;
+    numStars = 0;
 
     if (*p == '^') {
 	anchorLeft = 1;
@@ -3450,6 +3451,7 @@ TclReToGlob(
 		    if (!lastIsStar) {
 			*dsStr++ = '*';
 			lastIsStar = 1;
+			numStars++;
 		    }
 		    continue;
 		} else if (p[1] == '+') {
@@ -3457,6 +3459,7 @@ TclReToGlob(
 		    *dsStr++ = '?';
 		    *dsStr++ = '*';
 		    lastIsStar = 1;
+		    numStars++;
 		    continue;
 		}
 	    }
@@ -3480,6 +3483,15 @@ TclReToGlob(
 	}
 	lastIsStar = 0;
     }
+    if (numStars > 1) {
+	/*
+	 * Heuristic: if >1 non-anchoring *, the risk is large that glob
+	 * matching is slower than the RE engine, so report invalid.
+	 */
+	msg = "excessive recursive glob backtrack potential";
+	goto invalidGlob;
+    }
+
     if (!anchorRight && !lastIsStar) {
 	*dsStr++ = '*';
     }
-- 
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