From 91bc03a0dc30a013b46b4b3a697fbd426cd0dec1 Mon Sep 17 00:00:00 2001
From: Robert Knight <robertknight@gmail.com>
Date: Sat, 28 Apr 2007 11:49:34 +0000
Subject: [PATCH] Abort filter processing if the filter regexp matches the
 empty string.  Fixes filter getting stuck in infinite loop.  Use a static
 const QRegExp for the URL filter regexp since it never changes.

svn path=/branches/work/konsole-split-view/; revision=658740
---
 konsole/Filter.cpp | 27 ++++++++++++++++-----------
 konsole/Filter.h   | 21 +++++++++++++++++----
 2 files changed, 33 insertions(+), 15 deletions(-)

diff --git a/konsole/Filter.cpp b/konsole/Filter.cpp
index a5f4e35ff..127387807 100644
--- a/konsole/Filter.cpp
+++ b/konsole/Filter.cpp
@@ -345,7 +345,7 @@ QStringList RegExpFilter::HotSpot::capturedTexts() const
 
 void RegExpFilter::setRegExp(const QRegExp& regExp) 
 {
-    _searchText = QRegExp(regExp);
+    _searchText = regExp;
 }
 QRegExp RegExpFilter::regExp() const
 {
@@ -362,8 +362,10 @@ void RegExpFilter::process()
 
     Q_ASSERT( text );
 
-    // empty regexp does not match
-    if ( _searchText.isEmpty() )
+    // ignore any regular expressions which match an empty string.
+    // otherwise the while loop below will run indefinitely
+    static const QString emptyString("");
+    if ( _searchText.exactMatch(emptyString) )
         return;
 
     while(pos >= 0)
@@ -394,6 +396,8 @@ void RegExpFilter::process()
             addHotSpot( spot );  
             pos += _searchText.matchedLength();
 
+            // if matchedLength == 0, the program will get stuck in an infinite loop
+            Q_ASSERT( _searchText.matchedLength() > 0 );
         }
     }    
 }
@@ -433,9 +437,9 @@ UrlFilter::HotSpot::UrlType UrlFilter::HotSpot::urlType() const
 {
     QString url = capturedTexts().first();
     
-    if ( QRegExp(FullUrlRegExp).exactMatch(url) )
+    if ( FullUrlRegExp.exactMatch(url) )
         return StandardUrl;
-    else if ( QRegExp(EmailAddressRegExp).exactMatch(url) )
+    else if ( EmailAddressRegExp.exactMatch(url) )
         return Email;
     else
         return Unknown;
@@ -480,17 +484,18 @@ void UrlFilter::HotSpot::activate(QObject* object)
 //regexp matches:
 // full url:  
 // protocolname:// or www. followed by numbers, letters dots and dashes or the '@' character. 
-const QString UrlFilter::FullUrlRegExp("([a-z]+://|www\\.)[a-zA-Z0-9@\\-\\./]+");
+const QRegExp UrlFilter::FullUrlRegExp("([a-z]+://|www\\.)[a-zA-Z0-9@\\-\\./]+");
 // email address:
 // [word chars, dots or dashes]@[word chars, dots or dashes].[word chars]
-const QString UrlFilter::EmailAddressRegExp("(\\w|\\.|-)+@(\\w|\\.|-)+\\.\\w+");
+const QRegExp UrlFilter::EmailAddressRegExp("(\\w|\\.|-)+@(\\w|\\.|-)+\\.\\w+");
+
+// matches full url or email address
+const QRegExp UrlFilter::CompleteUrlRegExp('('+FullUrlRegExp.pattern()+'|'+
+                                            EmailAddressRegExp.pattern()+')');
 
 UrlFilter::UrlFilter()
 {
-    //FIXME - There is a bug where URLs are not identified if they occur at the very
-    //end of the output ( the last characters before any trailing whitespace )
-
-    setRegExp( QRegExp('('+FullUrlRegExp+'|'+EmailAddressRegExp+')') );
+    setRegExp( CompleteUrlRegExp );
 }
 UrlFilter::HotSpot::~HotSpot()
 {
diff --git a/konsole/Filter.h b/konsole/Filter.h
index 734a09475..bba98d5ce 100644
--- a/konsole/Filter.h
+++ b/konsole/Filter.h
@@ -211,12 +211,22 @@ public:
     /** Constructs a new regular expression filter */
     RegExpFilter();
 
-    /** Sets the regular expression which the filter searches for in blocks of text */
+    /** 
+     * Sets the regular expression which the filter searches for in blocks of text. 
+     *
+     * Regular expressions which match the empty string are treated as not matching
+     * anything. 
+     */
     void setRegExp(const QRegExp& text);
     /** Returns the regular expression which the filter searches for in blocks of text */
     QRegExp regExp() const;
 
-    /** Reimplemented to search the filter's text buffer for text matching regExp() */
+    /** 
+     * Reimplemented to search the filter's text buffer for text matching regExp() 
+     *
+     * If regexp matches the empty string, then process() will return immediately
+     * without finding results. 
+     */
     virtual void process();
 
 protected:
@@ -275,8 +285,11 @@ protected:
 
 private:
     
-    static const QString FullUrlRegExp;
-    static const QString EmailAddressRegExp;
+    static const QRegExp FullUrlRegExp;
+    static const QRegExp EmailAddressRegExp;
+
+    // combined OR of FullUrlRegExp and EmailAddressRegExp
+    static const QRegExp CompleteUrlRegExp; 
 };
 
 class FilterObject : public QObject