Add QObjectUniquePtr

qgis · Jun 10, 2019 · 01f2ba9 · 01f2ba9
1 parent 13099cc
commit 01f2ba9
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Showing 4 changed files with 178 additions and 0 deletions.
diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
@@ -979,6 +979,7 @@ SET(QGIS_CORE_HDRS
   qgstilecache.h
   qgstracer.h
   qgstranslationcontext.h
+  qobjectuniqueptr.h 
 
   qgsvectordataprovider.h
   qgsvectorlayercache.h

diff --git a/src/core/qobjectuniqueptr.h b/src/core/qobjectuniqueptr.h
@@ -0,0 +1,106 @@
+#ifndef QOBJECTUNIQUEPTR_H
+#define QOBJECTUNIQUEPTR_H
+
+#include <qsharedpointer.h>
+#include <qtypeinfo.h>
+
+class QVariant;
+
+template <class T>
+class QObjectUniquePtr
+{
+    Q_STATIC_ASSERT_X( !std::is_pointer<T>::value, "QObjectUniquePtr's template type must not be a pointer type" );
+
+    template<typename U>
+    struct TypeSelector
+    {
+      typedef QObject Type;
+    };
+    template<typename U>
+    struct TypeSelector<const U>
+    {
+      typedef const QObject Type;
+    };
+    typedef typename TypeSelector<T>::Type QObjectType;
+    QWeakPointer<QObjectType> wp;
+  public:
+    inline QObjectUniquePtr() { }
+    inline QObjectUniquePtr( T *p ) : wp( p ) { }
+    // compiler-generated copy/move ctor/assignment operators are fine!
+
+    ~QObjectUniquePtr() { delete wp.data(); }
+
+    inline void swap( QObjectUniquePtr &other ) { wp.swap( other.wp ); }
+
+    inline QObjectUniquePtr<T> &operator=( T *p )
+    { wp.assign( static_cast<QObjectType *>( p ) ); return *this; }
+
+    inline T *data() const
+    { return static_cast<T *>( wp.data() ); }
+    inline T *operator->() const
+    { return data(); }
+    inline T &operator*() const
+    { return *data(); }
+    inline operator T *() const
+    { return data(); }
+
+    inline bool isNull() const
+    { return wp.isNull(); }
+
+    inline void clear()
+    { wp.clear(); }
+
+    T *release() { T *p = qobject_cast<T *>( wp.data() ); wp.clear(); return p; }
+
+    void reset( T *p = nullptr ) { delete wp.data(); wp = p; }
+};
+template <class T> Q_DECLARE_TYPEINFO_BODY( QObjectUniquePtr<T>, Q_MOVABLE_TYPE );
+
+template <class T>
+inline bool operator==( const T *o, const QObjectUniquePtr<T> &p )
+{ return o == p.operator->(); }
+
+template<class T>
+inline bool operator==( const QObjectUniquePtr<T> &p, const T *o )
+{ return p.operator->() == o; }
+
+template <class T>
+inline bool operator==( T *o, const QObjectUniquePtr<T> &p )
+{ return o == p.operator->(); }
+
+template<class T>
+inline bool operator==( const QObjectUniquePtr<T> &p, T *o )
+{ return p.operator->() == o; }
+
+template<class T>
+inline bool operator==( const QObjectUniquePtr<T> &p1, const QObjectUniquePtr<T> &p2 )
+{ return p1.operator->() == p2.operator->(); }
+
+template <class T>
+inline bool operator!=( const T *o, const QObjectUniquePtr<T> &p )
+{ return o != p.operator->(); }
+
+template<class T>
+inline bool operator!= ( const QObjectUniquePtr<T> &p, const T *o )
+{ return p.operator->() != o; }
+
+template <class T>
+inline bool operator!=( T *o, const QObjectUniquePtr<T> &p )
+{ return o != p.operator->(); }
+
+template<class T>
+inline bool operator!= ( const QObjectUniquePtr<T> &p, T *o )
+{ return p.operator->() != o; }
+
+template<class T>
+inline bool operator!= ( const QObjectUniquePtr<T> &p1, const QObjectUniquePtr<T> &p2 )
+{ return p1.operator->() != p2.operator->() ; }
+
+template<typename T>
+QObjectUniquePtr<T>
+QObjectUniquePtrFromVariant( const QVariant &variant )
+{
+  return QObjectUniquePtr<T>( qobject_cast<T *>( QtSharedPointer::weakPointerFromVariant_internal( variant ).data() ) );
+}
+
+#endif // QOBJECTUNIQUEPTR_H
diff --git a/tests/src/core/CMakeLists.txt b/tests/src/core/CMakeLists.txt
@@ -219,6 +219,7 @@ SET(TESTS
  testqgsmimedatautils.cpp
  testqgsofflineediting.cpp
  testqgstranslateproject.cpp
+ testqobjectuniqueptr.cpp
    )
 
 IF(WITH_QTWEBKIT)

diff --git a/tests/src/core/testqobjectuniqueptr.cpp b/tests/src/core/testqobjectuniqueptr.cpp
@@ -0,0 +1,70 @@
+/***************************************************************************
+  testqobjectuniqueptr.cpp
+  --------------------------------------
+  Date                 :
+  Copyright            : (C) 2019 by Matthias Kuhn
+  Email                : matthias@opengis.ch
+ ***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#include "qgstest.h"
+#include "qobjectuniqueptr.h"
+
+#include "qgstest.h"
+
+class TestQObjectUniquePtr : public QObject
+{
+    Q_OBJECT
+
+  private slots:
+    void testMemLeak();
+    void testParentDeletedFirst();
+    void testParentDeletedAfter();
+};
+
+
+
+void TestQObjectUniquePtr::testMemLeak()
+{
+  QObject *myobj = new QObject();
+  QObjectUniquePtr<QObject> obj( myobj );
+}
+
+void TestQObjectUniquePtr::testParentDeletedFirst()
+{
+  QObject *parent = new QObject();
+  QObject *child = new QObject( parent );
+
+  QObjectUniquePtr<QObject> obj( child );
+  QVERIFY( !obj.isNull() );
+
+  delete parent;
+  QVERIFY( obj.isNull() );
+}
+
+void TestQObjectUniquePtr::testParentDeletedAfter()
+{
+  QObject *parent = new QObject();
+  QObject *child = new QObject( parent );
+  QPointer<QObject> observer( child );
+
+  {
+    QObjectUniquePtr<QObject> obj( child );
+    QVERIFY( !observer.isNull() );
+  }
+  QVERIFY( observer.isNull() );
+
+
+  // Basically shouldn't crash because of double delete on this line
+  delete parent;
+  QVERIFY( observer.isNull() );
+}
+
+QGSTEST_MAIN( TestQObjectUniquePtr )
+#include "testqobjectuniqueptr.moc"