1 files changed, 112 insertions, 0 deletions
diff --git a/src/plugins/platforms/windows/qwindowscombase.h b/src/plugins/platforms/windows/qwindowscombase.h
new file mode 100644
index 0000000000..5e51b6b7b7
--- /dev/null
+++ b/src/plugins/platforms/windows/qwindowscombase.h
@@ -0,0 +1,112 @@
+/****************************************************************************
+**
+** Copyright (C) 2017 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the plugins of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QWINDOWSCOMBASE_H
+#define QWINDOWSCOMBASE_H
+
+#include <QtCore/QtGlobal>
+
+#include <unknwn.h>
+
+QT_BEGIN_NAMESPACE
+
+// The __uuidof operator of MinGW does not work for all interfaces (for example,
+// IAccessible2). Specializations of this function can be provides to work
+// around this.
+template <class DesiredInterface>
+static IID qUuidOf() { return __uuidof(DesiredInterface); }
+
+// Helper for implementing IUnknown::QueryInterface.
+template <class DesiredInterface, class Derived>
+bool qWindowsComQueryInterface(Derived *d, REFIID id, LPVOID *iface)
+{
+    if (id == qUuidOf<DesiredInterface>()) {
+        *iface = static_cast<DesiredInterface *>(d);
+        d->AddRef();
+        return true;
+    }
+    return false;
+}
+
+// Helper for implementing IUnknown::QueryInterface for IUnknown
+// in the case of multiple inheritance via the first inherited class.
+template <class FirstInheritedInterface, class Derived>
+bool qWindowsComQueryUnknownInterfaceMulti(Derived *d, REFIID id, LPVOID *iface)
+{
+    if (id == __uuidof(IUnknown)) {
+        *iface = static_cast<FirstInheritedInterface *>(d);
+        d->AddRef();
+        return true;
+    }
+    return false;
+}
+
+// Helper base class to provide IUnknown methods for COM classes (single inheritance)
+template <class ComInterface> class QWindowsComBase : public ComInterface
+{
+    Q_DISABLE_COPY(QWindowsComBase)
+public:
+    explicit QWindowsComBase(ULONG initialRefCount = 1) : m_ref(initialRefCount) {}
+    virtual ~QWindowsComBase() {}
+
+    HRESULT STDMETHODCALLTYPE QueryInterface(REFIID id, LPVOID *iface)
+    {
+        *iface = nullptr;
+        return qWindowsComQueryInterface<IUnknown>(this, id, iface) || qWindowsComQueryInterface<ComInterface>(this, id, iface)
+            ? S_OK : E_NOINTERFACE;
+    }
+
+    ULONG STDMETHODCALLTYPE AddRef() { return ++m_ref; }
+
+    ULONG STDMETHODCALLTYPE Release()
+    {
+        if (!--m_ref) {
+            delete this;
+            return 0;
+        }
+        return m_ref;
+    }
+
+private:
+    ULONG m_ref;
+};
+
+QT_END_NAMESPACE
+
+#endif // QWINDOWSCOMBASE_H