1 files changed, 20 insertions, 53 deletions

diff --git a/src/tools/qstring.cpp b/src/tools/qstring.cpp
index 251637d..014dc23 100644
--- a/src/tools/qstring.cpp
+++ b/src/tools/qstring.cpp
@@ -1048,13 +1048,9 @@ QStringData::QStringData() : QShared(),
 	islatin1(FALSE),
 	security_unpaged(FALSE) {
 #ifdef QT_THREAD_SUPPORT
-	mutex = new QMutex( TRUE );
-	mutex->lock();
+	mutex = new QMutex(FALSE);
 #endif // QT_THREAD_SUPPORT
 	ref();
-#ifdef QT_THREAD_SUPPORT
-	mutex->unlock();
-#endif // QT_THREAD_SUPPORT
 }
 
 QStringData::QStringData(QChar *u, uint l, uint m) : QShared(),
@@ -1066,7 +1062,7 @@ QStringData::QStringData(QChar *u, uint l, uint m) : QShared(),
 	islatin1(FALSE),
 	security_unpaged(FALSE) {
 #ifdef QT_THREAD_SUPPORT
-	mutex = new QMutex( TRUE );
+	mutex = new QMutex(FALSE);
 #endif // QT_THREAD_SUPPORT
 }
 
@@ -1494,13 +1490,6 @@ QString::QString() :
     d(0)
 {
 	d = shared_null ? shared_null : makeSharedNull();
-#ifdef QT_THREAD_SUPPORT
-	d->mutex->lock();
-#endif // QT_THREAD_SUPPORT
-	d->ref();
-#ifdef QT_THREAD_SUPPORT
-	d->mutex->unlock();
-#endif // QT_THREAD_SUPPORT
 }
 
 /*!
@@ -1519,15 +1508,15 @@ QString::QString( QChar ch )
 QString::QString( const QString &s ) :
     d(s.d)
 {
+    if (d != shared_null) {
 #ifdef QT_THREAD_SUPPORT
-    d->mutex->lock();
+        d->mutex->lock();
 #endif // QT_THREAD_SUPPORT
-
-    d->ref();
-
+        d->ref();
 #ifdef QT_THREAD_SUPPORT
-    d->mutex->unlock();
+        d->mutex->unlock();
 #endif // QT_THREAD_SUPPORT
+    }
 }
 
 /*!
@@ -1550,13 +1539,6 @@ QString::QString( int size, bool /*dummy*/ )
 	d = new QStringData( uc, 0, l );
     } else {
 	d = shared_null ? shared_null : (shared_null=new QStringData);
-#ifdef QT_THREAD_SUPPORT
-	d->mutex->lock();
-#endif // QT_THREAD_SUPPORT
-	d->ref();
-#ifdef QT_THREAD_SUPPORT
-	d->mutex->unlock();
-#endif // QT_THREAD_SUPPORT
     }
 }
 
@@ -1598,13 +1580,6 @@ QString::QString( const QChar* unicode, uint length )
 {
     if ( !unicode && !length ) {
 	d = shared_null ? shared_null : makeSharedNull();
-#ifdef QT_THREAD_SUPPORT
-	d->mutex->lock();
-#endif // QT_THREAD_SUPPORT
-	d->ref();
-#ifdef QT_THREAD_SUPPORT
-	d->mutex->unlock();
-#endif // QT_THREAD_SUPPORT
     }
     else {
 	QChar* uc = QT_ALLOC_QCHAR_VEC( length );
@@ -1689,22 +1664,19 @@ QString::~QString()
 	}
 #endif
 
+	if (d == shared_null) {
+		return;
+	}
+
 #ifdef QT_THREAD_SUPPORT
 	d->mutex->lock();
 #endif // QT_THREAD_SUPPORT
 	if ( d->deref() ) {
-		if ( d != shared_null ) {
 #ifdef QT_THREAD_SUPPORT
-			d->mutex->unlock();
-#endif // QT_THREAD_SUPPORT
-			d->deleteSelf();
-			d = NULL;
-		}
-		else {
-#ifdef QT_THREAD_SUPPORT
-			d->mutex->unlock();
+		d->mutex->unlock();
 #endif // QT_THREAD_SUPPORT
-		}
+		d->deleteSelf();
+		d = NULL;
 	}
 	else {
 #ifdef QT_THREAD_SUPPORT
@@ -1730,7 +1702,7 @@ void QString::real_detach()
 
 void QString::deref()
 {
-	if ( d ) {
+	if ( d && (d != shared_null) ) {
 #ifdef QT_THREAD_SUPPORT
 		d->mutex->lock();
 #endif // QT_THREAD_SUPPORT
@@ -1788,13 +1760,15 @@ void QStringData::deleteSelf()
 */
 QString &QString::operator=( const QString &s )
 {
+    if (s.d != shared_null) {
 #ifdef QT_THREAD_SUPPORT
-    s.d->mutex->lock();
+        s.d->mutex->lock();
 #endif // QT_THREAD_SUPPORT
-    s.d->ref();
+        s.d->ref();
 #ifdef QT_THREAD_SUPPORT
-    s.d->mutex->unlock();
+        s.d->mutex->unlock();
 #endif // QT_THREAD_SUPPORT
+    }
     deref();
     d = s.d;
 
@@ -6527,13 +6501,6 @@ QString& QString::setUnicode( const QChar *unicode, uint len )
 		if ( d != shared_null ) {       // beware of nullstring being set to nullstring
 			deref();
 			d = shared_null ? shared_null : makeSharedNull();
-#ifdef QT_THREAD_SUPPORT
-			d->mutex->lock();
-#endif // QT_THREAD_SUPPORT
-			d->ref();
-#ifdef QT_THREAD_SUPPORT
-			d->mutex->unlock();
-#endif // QT_THREAD_SUPPORT
 		}
 	}
 	else {