Fix a number of threading problems and crashes

This partially resolves Bug 1467

2 files changed, 335 insertions, 28 deletions

diff --git a/src/tools/qglist.cpp b/src/tools/qglist.cpp
index b04ac75..fb94427 100644
--- a/src/tools/qglist.cpp
+++ b/src/tools/qglist.cpp
@@ -43,6 +43,10 @@
 #include "qdatastream.h"
 #include "qvaluelist.h"
 
+#if defined(QT_THREAD_SUPPORT)
+  #include "qmutex.h"
+#endif // defined(QT_THREAD_SUPPORT)
+
 /*!
   \class QLNode qglist.h
   \reentrant
@@ -221,6 +225,9 @@ QDataStream &QGList::write( QDataStream &s, QPtrCollection::Item ) const
 
 QGList::QGList()
 {
+#if defined(QT_THREAD_SUPPORT)
+    //mutex = new QMutex(true);
+#endif
     firstNode = lastNode = curNode = 0;		// initialize list
     numNodes  = 0;
     curIndex  = -1;
@@ -234,6 +241,9 @@ QGList::QGList()
 QGList::QGList( const QGList & list )
     : QPtrCollection( list )
 {
+#if defined(QT_THREAD_SUPPORT)
+    //mutex = new QMutex(true);
+#endif
     firstNode = lastNode = curNode = 0;		// initialize list
     numNodes  = 0;
     curIndex  = -1;
@@ -258,6 +268,9 @@ QGList::~QGList()
     // twice on the same address! This is insane but let's try not to crash
     // here.
     iterators = 0;
+#if defined(QT_THREAD_SUPPORT)
+    //delete mutex;
+#endif
 }
 
 
@@ -290,11 +303,13 @@ QGList& QGList::operator=( const QGList &list )
 
 bool QGList::operator==( const QGList &list ) const
 {
-    if ( count() != list.count() )
+    if ( count() != list.count() ) {
 	return FALSE;
+    }
 
-    if ( count() == 0 )
+    if ( count() == 0 ) {
 	return TRUE;
+    }
 
     QLNode *n1 = firstNode;
     QLNode *n2 = list.firstNode;
@@ -322,8 +337,15 @@ bool QGList::operator==( const QGList &list ) const
 
 QLNode *QGList::locate( uint index )
 {
-    if ( index == (uint)curIndex )		// current node ?
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->lock();
+#endif
+    if ( index == (uint)curIndex ) {		// current node ?
+#if defined(QT_THREAD_SUPPORT)
+	//mutex->unlock();
+#endif
 	return curNode;
+    }
     if ( !curNode && firstNode ) {		// set current node
 	curNode	 = firstNode;
 	curIndex = 0;
@@ -332,13 +354,18 @@ QLNode *QGList::locate( uint index )
     int	 distance = index - curIndex;		// node distance to cur node
     bool forward;				// direction to traverse
 
-    if ( index >= numNodes )
+    if ( index >= numNodes ) {
+#if defined(QT_THREAD_SUPPORT)
+	//mutex->unlock();
+#endif
 	return 0;
+    }
 
-    if ( distance < 0 )
+    if ( distance < 0 ) {
 	distance = -distance;
+    }
     if ( (uint)distance < index && (uint)distance < numNodes - index ) {
-	node =	curNode;			// start from current node
+	node = curNode;				// start from current node
 	forward = index > (uint)curIndex;
     } else if ( index < numNodes - index ) {	// start from first node
 	node = firstNode;
@@ -352,13 +379,18 @@ QLNode *QGList::locate( uint index )
 	forward = FALSE;
     }
     if ( forward ) {				// now run through nodes
-	while ( distance-- )
+	while ( distance-- ) {
 	    node = node->next;
+	}
     } else {
-	while ( distance-- )
+	while ( distance-- ) {
 	    node = node->prev;
+	}
     }
     curIndex = index;				// must update index
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->unlock();
+#endif
     return curNode = node;
 }
 
@@ -369,6 +401,9 @@ QLNode *QGList::locate( uint index )
 
 void QGList::inSort( QPtrCollection::Item d )
 {
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->lock();
+#endif
     int index = 0;
     register QLNode *n = firstNode;
     while ( n && compareItems(n->data,d) < 0 ){ // find position in list
@@ -376,6 +411,9 @@ void QGList::inSort( QPtrCollection::Item d )
 	index++;
     }
     insertAt( index, d );
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->unlock();
+#endif
 }
 
 
@@ -385,6 +423,9 @@ void QGList::inSort( QPtrCollection::Item d )
 
 void QGList::prepend( QPtrCollection::Item d )
 {
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->lock();
+#endif
     register QLNode *n = new QLNode( newItem(d) );
     Q_CHECK_PTR( n );
     n->prev = 0;
@@ -395,6 +436,9 @@ void QGList::prepend( QPtrCollection::Item d )
     firstNode = curNode = n;			// curNode affected
     numNodes++;
     curIndex = 0;
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->unlock();
+#endif
 }
 
 
@@ -404,16 +448,24 @@ void QGList::prepend( QPtrCollection::Item d )
 
 void QGList::append( QPtrCollection::Item d )
 {
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->lock();
+#endif
     register QLNode *n = new QLNode( newItem(d) );
     Q_CHECK_PTR( n );
     n->next = 0;
-    if ( (n->prev = lastNode) )			// list is not empty
+    if ( (n->prev = lastNode) ) {		// list is not empty
 	lastNode->next = n;
-    else					// initialize list
+    }
+    else {					// initialize list
 	firstNode = n;
+    }
     lastNode = curNode = n;			// curNode affected
     curIndex = numNodes;
     numNodes++;
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->unlock();
+#endif
 }
 
 
@@ -423,25 +475,43 @@ void QGList::append( QPtrCollection::Item d )
 
 bool QGList::insertAt( uint index, QPtrCollection::Item d )
 {
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->lock();
+#endif
     if ( index == 0 ) {
 	prepend( d );
+#if defined(QT_THREAD_SUPPORT)
+	//mutex->unlock();
+#endif
 	return TRUE;
-    } else if ( index == numNodes ) {
+    }
+    else if ( index == numNodes ) {
 	append( d );
+#if defined(QT_THREAD_SUPPORT)
+	//mutex->unlock();
+#endif
 	return TRUE;
     }
     QLNode *nextNode = locate( index );
-    if ( !nextNode )
+    if ( !nextNode ) {
+#if defined(QT_THREAD_SUPPORT)
+	//mutex->unlock();
+#endif
 	return FALSE;
+    }
     QLNode *prevNode = nextNode->prev;
     register QLNode *n = new QLNode( newItem(d) );
     Q_CHECK_PTR( n );
     nextNode->prev = n;
+    Q_ASSERT( (!((curIndex > 0) && (!prevNode))) );
     prevNode->next = n;
     n->prev = prevNode;				// link new node into list
     n->next = nextNode;
     curNode = n;				// curIndex set by locate()
     numNodes++;
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->unlock();
+#endif
     return TRUE;
 }
 
@@ -452,18 +522,30 @@ bool QGList::insertAt( uint index, QPtrCollection::Item d )
 
 void QGList::relinkNode( QLNode *n )
 {
-    if ( n == firstNode )			// already first
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->lock();
+#endif
+    if ( n == firstNode ) {			// already first
+#if defined(QT_THREAD_SUPPORT)
+	//mutex->unlock();
+#endif
 	return;
+    }
     curNode = n;
     unlink();
     n->prev = 0;
-    if ( (n->next = firstNode) )		// list is not empty
+    if ( (n->next = firstNode) ) {		// list is not empty
 	firstNode->prev = n;
-    else					// initialize list
+    }
+    else {					// initialize list
 	lastNode = n;
+    }
     firstNode = curNode = n;			// curNode affected
     numNodes++;
     curIndex = 0;
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->unlock();
+#endif
 }
 
 
@@ -473,8 +555,15 @@ void QGList::relinkNode( QLNode *n )
 
 QLNode *QGList::unlink()
 {
-    if ( curNode == 0 )				// null current node
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->lock();
+#endif
+    if ( curNode == 0 ) {			// null current node
+#if defined(QT_THREAD_SUPPORT)
+	//mutex->unlock();
+#endif
 	return 0;
+    }
     register QLNode *n = curNode;		// unlink this node
     if ( n == firstNode ) {			// removing first node ?
 	if ( (firstNode = n->next) ) {
@@ -500,9 +589,13 @@ QLNode *QGList::unlink()
         curIndex--;
     }
 
-    if ( iterators )
+    if ( iterators ) {
 	iterators->notifyRemove( n, curNode );
+    }
     numNodes--;
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->unlock();
+#endif
     return n;
 }
 
@@ -513,6 +606,9 @@ QLNode *QGList::unlink()
 
 bool QGList::removeNode( QLNode *n )
 {
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->lock();
+#endif
 #if defined(QT_CHECK_NULL)
     if ( n == 0 || (n->prev && n->prev->next != n) ||
 	 (n->next && n->next->prev != n) ) {
@@ -526,6 +622,9 @@ bool QGList::removeNode( QLNode *n )
     delete n;
     curNode  = firstNode;
     curIndex = curNode ? 0 : -1;
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->unlock();
+#endif
     return TRUE;
 }
 
@@ -537,13 +636,27 @@ bool QGList::removeNode( QLNode *n )
 
 bool QGList::remove( QPtrCollection::Item d )
 {
-    if ( d && find(d) == -1 )
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->lock();
+#endif
+    if ( d && find(d) == -1 ) {
+#if defined(QT_THREAD_SUPPORT)
+	//mutex->unlock();
+#endif
 	return FALSE;
+    }
     QLNode *n = unlink();
-    if ( !n )
+    if ( !n ) {
+#if defined(QT_THREAD_SUPPORT)
+	//mutex->unlock();
+#endif
 	return FALSE;
+    }
     deleteItem( n->data );
     delete n;
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->unlock();
+#endif
     return TRUE;
 }
 
@@ -553,13 +666,27 @@ bool QGList::remove( QPtrCollection::Item d )
 
 bool QGList::removeRef( QPtrCollection::Item d )
 {
-    if ( findRef(d) == -1 )
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->lock();
+#endif
+    if ( findRef(d) == -1 ) {
+#if defined(QT_THREAD_SUPPORT)
+	//mutex->unlock();
+#endif
 	return FALSE;
+    }
     QLNode *n = unlink();
-    if ( !n )
+    if ( !n ) {
+#if defined(QT_THREAD_SUPPORT)
+	//mutex->unlock();
+#endif
 	return FALSE;
+    }
     deleteItem( n->data );
     delete n;
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->unlock();
+#endif
     return TRUE;
 }
 
@@ -581,13 +708,27 @@ bool QGList::removeRef( QPtrCollection::Item d )
 
 bool QGList::removeAt( uint index )
 {
-    if ( !locate(index) )
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->lock();
+#endif
+    if ( !locate(index) ) {
+#if defined(QT_THREAD_SUPPORT)
+	//mutex->unlock();
+#endif
 	return FALSE;
+    }
     QLNode *n = unlink();
-    if ( !n )
+    if ( !n ) {
+#if defined(QT_THREAD_SUPPORT)
+	//mutex->unlock();
+#endif
 	return FALSE;
+    }
     deleteItem( n->data );
     delete n;
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->unlock();
+#endif
     return TRUE;
 }
 
@@ -597,13 +738,23 @@ bool QGList::removeAt( uint index )
 */
 bool QGList::replaceAt( uint index, QPtrCollection::Item d )
 {
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->lock();
+#endif
     QLNode *n = locate( index );
-    if ( !n )
+    if ( !n ) {
+#if defined(QT_THREAD_SUPPORT)
+	//mutex->unlock();
+#endif
 	return FALSE;
+    }
     if ( n->data != d ) {
 	deleteItem( n->data );
 	n->data = newItem( d );
     }
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->unlock();
+#endif
     return TRUE;
 }
 
@@ -615,10 +766,16 @@ bool QGList::replaceAt( uint index, QPtrCollection::Item d )
 
 QPtrCollection::Item QGList::takeNode( QLNode *n )
 {
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->lock();
+#endif
 #if defined(QT_CHECK_NULL)
     if ( n == 0 || (n->prev && n->prev->next != n) ||
 	 (n->next && n->next->prev != n) ) {
 	qWarning( "QGList::takeNode: Corrupted node" );
+#if defined(QT_THREAD_SUPPORT)
+	//mutex->unlock();
+#endif
 	return 0;
     }
 #endif
@@ -628,6 +785,9 @@ QPtrCollection::Item QGList::takeNode( QLNode *n )
     delete n;					// delete the node, not data
     curNode  = firstNode;
     curIndex = curNode ? 0 : -1;
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->unlock();
+#endif
     return d;
 }
 
@@ -637,9 +797,15 @@ QPtrCollection::Item QGList::takeNode( QLNode *n )
 
 QPtrCollection::Item QGList::take()
 {
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->lock();
+#endif
     QLNode *n = unlink();			// unlink node
     Item d = n ? n->data : 0;
     delete n;					// delete node, keep contents
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->unlock();
+#endif
     return d;
 }
 
@@ -649,11 +815,21 @@ QPtrCollection::Item QGList::take()
 
 QPtrCollection::Item QGList::takeAt( uint index )
 {
-    if ( !locate(index) )
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->lock();
+#endif
+    if ( !locate(index) ) {
+#if defined(QT_THREAD_SUPPORT)
+	//mutex->unlock();
+#endif
 	return 0;
+    }
     QLNode *n = unlink();			// unlink node
     Item d = n ? n->data : 0;
     delete n;					// delete node, keep contents
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->unlock();
+#endif
     return d;
 }
 
@@ -663,10 +839,16 @@ QPtrCollection::Item QGList::takeAt( uint index )
 
 QPtrCollection::Item QGList::takeFirst()
 {
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->lock();
+#endif
     first();
     QLNode *n = unlink();			// unlink node
     Item d = n ? n->data : 0;
     delete n;
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->unlock();
+#endif
     return d;
 }
 
@@ -676,10 +858,16 @@ QPtrCollection::Item QGList::takeFirst()
 
 QPtrCollection::Item QGList::takeLast()
 {
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->lock();
+#endif
     last();
     QLNode *n = unlink();			// unlink node
     Item d = n ? n->data : 0;
     delete n;
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->unlock();
+#endif
     return d;
 }
 
@@ -690,14 +878,18 @@ QPtrCollection::Item QGList::takeLast()
 
 void QGList::clear()
 {
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->lock();
+#endif
     register QLNode *n = firstNode;
 
     firstNode = lastNode = curNode = 0;		// initialize list
     numNodes = 0;
     curIndex = -1;
 
-    if ( iterators )
+    if ( iterators ) {
 	iterators->notifyClear( FALSE );
+    }
 
     QLNode *prevNode;
     while ( n ) {				// for all nodes ...
@@ -706,6 +898,9 @@ void QGList::clear()
 	n = n->next;
 	delete prevNode;			// deallocate node
     }
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->unlock();
+#endif
 }
 
 
@@ -716,6 +911,9 @@ void QGList::clear()
 
 int QGList::findRef( QPtrCollection::Item d, bool fromStart )
 {
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->lock();
+#endif
     register QLNode *n;
     int	     index;
     if ( fromStart ) {				// start from first node
@@ -731,6 +929,9 @@ int QGList::findRef( QPtrCollection::Item d, bool fromStart )
     }
     curNode = n;
     curIndex = n ? index : -1;
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->unlock();
+#endif
     return curIndex;				// return position of item
 }
 
@@ -742,6 +943,9 @@ int QGList::findRef( QPtrCollection::Item d, bool fromStart )
 
 int QGList::find( QPtrCollection::Item d, bool fromStart )
 {
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->lock();
+#endif
     register QLNode *n;
     int	     index;
     if ( fromStart ) {				// start from first node
@@ -757,6 +961,9 @@ int QGList::find( QPtrCollection::Item d, bool fromStart )
     }
     curNode = n;
     curIndex = n ? index : -1;
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->unlock();
+#endif
     return curIndex;				// return position of item
 }
 
@@ -767,6 +974,9 @@ int QGList::find( QPtrCollection::Item d, bool fromStart )
 
 uint QGList::containsRef( QPtrCollection::Item d ) const
 {
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->lock();
+#endif
     register QLNode *n = firstNode;
     uint     count = 0;
     while ( n ) {				// for all nodes...
@@ -774,6 +984,9 @@ uint QGList::containsRef( QPtrCollection::Item d ) const
 	    count++;
 	n = n->next;
     }
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->unlock();
+#endif
     return count;
 }
 
@@ -784,6 +997,9 @@ uint QGList::containsRef( QPtrCollection::Item d ) const
 
 uint QGList::contains( QPtrCollection::Item d ) const
 {
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->lock();
+#endif
     register QLNode *n = firstNode;
     uint     count = 0;
     QGList  *that = (QGList*)this;		// mutable for compareItems()
@@ -792,6 +1008,9 @@ uint QGList::contains( QPtrCollection::Item d ) const
 	    count++;
 	n = n->next;
     }
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->unlock();
+#endif
     return count;
 }
 
@@ -839,10 +1058,19 @@ uint QGList::contains( QPtrCollection::Item d ) const
 
 QPtrCollection::Item QGList::first()
 {
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->lock();
+#endif
     if ( firstNode ) {
 	curIndex = 0;
+#if defined(QT_THREAD_SUPPORT)
+	//mutex->unlock();
+#endif
 	return (curNode=firstNode)->data;
     }
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->unlock();
+#endif
     return 0;
 }
 
@@ -852,10 +1080,19 @@ QPtrCollection::Item QGList::first()
 
 QPtrCollection::Item QGList::last()
 {
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->lock();
+#endif
     if ( lastNode ) {
 	curIndex = numNodes-1;
+#if defined(QT_THREAD_SUPPORT)
+	//mutex->unlock();
+#endif
 	return (curNode=lastNode)->data;
     }
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->unlock();
+#endif
     return 0;
 }
 
@@ -865,15 +1102,24 @@ QPtrCollection::Item QGList::last()
 
 QPtrCollection::Item QGList::next()
 {
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->lock();
+#endif
     if ( curNode ) {
 	if ( curNode->next ) {
 	    curIndex++;
 	    curNode = curNode->next;
+#if defined(QT_THREAD_SUPPORT)
+	    //mutex->unlock();
+#endif
 	    return curNode->data;
 	}
 	curIndex = -1;
 	curNode = 0;
     }
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->unlock();
+#endif
     return 0;
 }
 
@@ -883,15 +1129,24 @@ QPtrCollection::Item QGList::next()
 
 QPtrCollection::Item QGList::prev()
 {
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->lock();
+#endif
     if ( curNode ) {
 	if ( curNode->prev ) {
 	    curIndex--;
 	    curNode = curNode->prev;
+#if defined(QT_THREAD_SUPPORT)
+	    //mutex->unlock();
+#endif
 	    return curNode->data;
 	}
 	curIndex = -1;
 	curNode = 0;
     }
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->unlock();
+#endif
     return 0;
 }
 
@@ -902,9 +1157,16 @@ QPtrCollection::Item QGList::prev()
 
 void QGList::toVector( QGVector *vector ) const
 {
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->lock();
+#endif
     vector->clear();
-    if ( !vector->resize( count() ) )
+    if ( !vector->resize( count() ) ) {
+#if defined(QT_THREAD_SUPPORT)
+	//mutex->unlock();
+#endif
 	return;
+    }
     register QLNode *n = firstNode;
     uint i = 0;
     while ( n ) {
@@ -912,10 +1174,16 @@ void QGList::toVector( QGVector *vector ) const
 	n = n->next;
 	i++;
     }
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->unlock();
+#endif
 }
 
 void QGList::heapSortPushDown( QPtrCollection::Item* heap, int first, int last )
 {
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->lock();
+#endif
     int r = first;
     while( r <= last/2 ) {
 	// Node r has only one child ?
@@ -950,6 +1218,9 @@ void QGList::heapSortPushDown( QPtrCollection::Item* heap, int first, int last )
 	    }
 	}
     }
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->unlock();
+#endif
 }
 
 
@@ -962,9 +1233,16 @@ void QGList::heapSortPushDown( QPtrCollection::Item* heap, int first, int last )
 
 void QGList::sort()
 {
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->lock();
+#endif
     uint n = count();
-    if ( n < 2 )
+    if ( n < 2 ) {
+#if defined(QT_THREAD_SUPPORT)
+	//mutex->unlock();
+#endif
 	return;
+    }
 
     // Create the heap
     QPtrCollection::Item* realheap = new QPtrCollection::Item[ n ];
@@ -995,6 +1273,9 @@ void QGList::sort()
     }
 
     delete [] realheap;
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->unlock();
+#endif
 }
 
 
@@ -1019,6 +1300,9 @@ QDataStream &operator<<( QDataStream &s, const QGList &list )
 
 QDataStream &QGList::read( QDataStream &s )
 {
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->lock();
+#endif
     uint num;
     s >> num;					// read number of items
     clear();					// clear list
@@ -1042,6 +1326,9 @@ QDataStream &QGList::read( QDataStream &s )
     }
     curNode  = firstNode;
     curIndex = curNode ? 0 : -1;
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->unlock();
+#endif
     return s;
 }
 
@@ -1051,12 +1338,18 @@ QDataStream &QGList::read( QDataStream &s )
 
 QDataStream &QGList::write( QDataStream &s ) const
 {
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->lock();
+#endif
     s << count();				// write number of items
     QLNode *n = firstNode;
     while ( n ) {				// write all items
 	write( s, n->data );
 	n = n->next;
     }
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->unlock();
+#endif
     return s;
 }
 
@@ -1068,9 +1361,15 @@ QDataStream &QGList::write( QDataStream &s ) const
  */
 QLNode* QGList::erase( QLNode* it )
 {
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->lock();
+#endif
     QLNode* n = it;
     it = it->next;
     removeNode( n );
+#if defined(QT_THREAD_SUPPORT)
+    //mutex->unlock();
+#endif
     return it;
 }
 
diff --git a/src/tools/qglist.h b/src/tools/qglist.h
index fadc46c..dfacf47 100644
--- a/src/tools/qglist.h
+++ b/src/tools/qglist.h
@@ -59,6 +59,8 @@ private:
     QLNode( QPtrCollection::Item d ) { data = d; }
 };
 
+class QMutex;
+class QGListPrivate;
 class QGListIteratorList; // internal helper class
 
 class Q_EXPORT QGList : public QPtrCollection	// doubly linked generic list
@@ -147,6 +149,12 @@ private:
 
     QLNode *locate( uint );			// get node at i'th pos
     QLNode *unlink();				// unlink node
+
+#if defined(QT_THREAD_SUPPORT)
+//     QMutex* mutex;
+#endif
+
+//     QGListPrivate* d;
 };