From 71a6d7870f609df603d9520a8d292055ea5928c3 Mon Sep 17 00:00:00 2001
From: Michele Calgaro <michele.calgaro@yahoo.it>
Date: Sat, 2 Aug 2014 21:18:48 +0900
Subject: [PATCH] Improvements to QValueList. This may relate to bug 1820

---
 src/tools/qvaluelist.h | 42 ++++++++++++++++++++++--------------------
 1 file changed, 22 insertions(+), 20 deletions(-)

diff --git a/src/tools/qvaluelist.h b/src/tools/qvaluelist.h
index 9365cd8..2976214 100644
--- a/src/tools/qvaluelist.h
+++ b/src/tools/qvaluelist.h
@@ -229,12 +229,6 @@ public:
     QValueListPrivate();
     QValueListPrivate( const QValueListPrivate<T>& _p );
 
-    void derefAndDelete() // ### hack to get around hp-cc brain damage
-    {
-	if ( deref() )
-	    delete this;
-    }
-
 #if defined(Q_TEMPLATEDLL)
     // Workaround MS bug in memory de/allocation in DLL vs. EXE
     virtual
@@ -258,14 +252,14 @@ public:
 template <class T>
 Q_INLINE_TEMPLATES QValueListPrivate<T>::QValueListPrivate()
 {
-    node = new Node; node->next = node->prev = node; nodes = 0;
+    node = new Node(); node->next = node->prev = node; nodes = 0;
 }
 
 template <class T>
 Q_INLINE_TEMPLATES QValueListPrivate<T>::QValueListPrivate( const QValueListPrivate<T>& _p )
     : QShared()
 {
-    node = new Node; node->next = node->prev = node; nodes = 0;
+    node = new Node(); node->next = node->prev = node; nodes = 0;
     Iterator b( _p.node->next );
     Iterator e( _p.node );
     Iterator i( node );
@@ -452,15 +446,23 @@ public:
 	qCopy( l.begin(), l.end(), std::back_inserter( *this ) );
     }
 #endif
-    ~QValueList() { sh->derefAndDelete(); }
+    ~QValueList()
+    {
+        if (sh->deref())
+	    delete sh;
+    }
 
     QValueList<T>& operator= ( const QValueList<T>& l )
     {
+        if (this == &l || sh == l.sh)
+            return *this;  // Do nothing is self-assigning
 	l.sh->ref();
-	sh->derefAndDelete();
+        if (sh->deref())
+	    delete sh;
 	sh = l.sh;
 	return *this;
     }
+    
 #ifndef QT_NO_STL
     QValueList<T>& operator= ( const std::list<T>& l )
     {
@@ -468,6 +470,7 @@ public:
 	qCopy( l.begin(), l.end(), std::back_inserter( *this ) );
 	return *this;
     }
+    
     bool operator== ( const std::list<T>& l ) const
     {
 	if ( size() != l.size() )
@@ -574,7 +577,14 @@ protected:
     /**
      * Helpers
      */
-    void detach() { if ( sh->count > 1 ) detachInternal(); }
+    void detach()
+    { 
+        if (sh->count > 1) 
+        {
+            sh->deref();
+            sh = new QValueListPrivate<T>(*sh);        
+        }
+    }
 
     /**
      * Variables
@@ -582,8 +592,6 @@ protected:
     QValueListPrivate<T>* sh;
 
 private:
-    void detachInternal();
-
     friend class QDeepCopy< QValueList<T> >;
 };
 
@@ -603,7 +611,7 @@ Q_INLINE_TEMPLATES bool QValueList<T>::operator== ( const QValueList<T>& l ) con
 template <class T>
 Q_INLINE_TEMPLATES void QValueList<T>::clear()
 {
-    if ( sh->count == 1 ) sh->clear(); else { sh->deref(); sh = new QValueListPrivate<T>; }
+    if ( sh->count == 1 ) sh->clear(); else { sh->deref(); sh = new QValueListPrivate<T>(); }
 }
 
 template <class T>
@@ -640,12 +648,6 @@ Q_INLINE_TEMPLATES QValueList<T>& QValueList<T>::operator+= ( const QValueList<T
     return *this;
 }
 
-template <class T>
-Q_INLINE_TEMPLATES void QValueList<T>::detachInternal()
-{
-    sh->deref(); sh = new QValueListPrivate<T>( *sh );
-}
-
 #ifndef QT_NO_DATASTREAM
 template <class T>
 Q_INLINE_TEMPLATES QDataStream& operator>>( QDataStream& s, QValueList<T>& l )