Asynchronous component instantiation

This introduces two main:

    * the QML compiler executes in a separate thread
    * item instantiation can be interrupted and resumed to
      allow it to be split across multiple frames.

Task-number: QTBUG-21151
Change-Id: I9631c62bb77da3a2e0c37f0da3719533fdce4fef
Reviewed-on: http://codereview.qt-project.org/5676
Reviewed-by: Martin Jones <martin.jones@nokia.com>

src/declarative/qml/ftw/ftw.pri

@@ -11,12 +11,14 @@ HEADERS +=  \
     $$PWD/qfieldlist_p.h \
     $$PWD/qfastmetabuilder_p.h \
     $$PWD/qhashfield_p.h \
+    $$PWD/qdeclarativethread_p.h \
+    $$PWD/qfinitestack_p.h \
 
 SOURCES += \
     $$PWD/qintrusivelist.cpp \
     $$PWD/qmetaobjectbuilder.cpp \
     $$PWD/qhashedstring.cpp \
-    $$PWD/qdeclarativerefcount.cpp \
     $$PWD/qdeclarativepool.cpp \
     $$PWD/qfastmetabuilder.cpp \
+    $$PWD/qdeclarativethread.cpp \
 

src/declarative/qml/ftw/qdeclarativerefcount_p.h

@@ -54,23 +54,27 @@
 //
 
 #include <QtCore/qglobal.h>
+#include <QtCore/qatomic.h>
 
 QT_BEGIN_HEADER
 
 QT_BEGIN_NAMESPACE
 
 QT_MODULE(Declarative)
 
-class Q_DECLARATIVE_EXPORT QDeclarativeRefCount
+class QDeclarativeRefCount
 {
 public:
-    QDeclarativeRefCount();
-    virtual ~QDeclarativeRefCount();
-    void addref();
-    void release();
+    inline QDeclarativeRefCount();
+    inline virtual ~QDeclarativeRefCount();
+    inline void addref();
+    inline void release();
+
+protected:
+    inline virtual void destroy();
 
 private:
-    int refCount;
+    QAtomicInt refCount;
 };
 
 template<class T>
@@ -92,10 +96,40 @@ class QDeclarativeRefPointer
     inline operator T*() const { return o; }
     inline T* data() const { return o; }
 
+    inline QDeclarativeRefPointer<T> &take(T *);
+
 private:
     T *o;
 };
 
+QDeclarativeRefCount::QDeclarativeRefCount() 
+: refCount(1) 
+{
+}
+
+QDeclarativeRefCount::~QDeclarativeRefCount() 
+{
+    Q_ASSERT(refCount == 0);
+}
+
+void QDeclarativeRefCount::addref() 
+{ 
+    Q_ASSERT(refCount > 0); 
+    refCount.ref(); 
+}
+
+void QDeclarativeRefCount::release() 
+{ 
+    Q_ASSERT(refCount > 0); 
+    if (!refCount.deref()) 
+        destroy(); 
+}
+
+void QDeclarativeRefCount::destroy() 
+{ 
+    delete this; 
+}
+
 template<class T>
 QDeclarativeRefPointer<T>::QDeclarativeRefPointer()
 : o(0) 
@@ -140,6 +174,18 @@ QDeclarativeRefPointer<T> &QDeclarativeRefPointer<T>::operator=(T *other)
     return *this;
 }
 
+/*!
+Takes ownership of \a other.  take() does *not* add a reference, as it assumes ownership
+of the callers reference of other.
+*/
+template<class T>
+QDeclarativeRefPointer<T> &QDeclarativeRefPointer<T>::take(T *other)
+{
+    if (o) o->release();
+    o = other;
+    return *this;
+}
+
 QT_END_NAMESPACE
 
 QT_END_HEADER