Add Platform and Platform_qtwidgets

So we can start removing QtWidgets vs QtQuick ifdefs.
Each "platform" will implement the differences

src/CMakeLists.txt

@@ -102,6 +102,10 @@ set(DOCKSLIBS_SRCS
     ViewWrapper.h
     Controller.cpp
     Controller.h
+    Platform.cpp
+    Platform.h
+    qtwidgets/Platform_qtwidgets.cpp
+    qtwidgets/Platform_qtwidgets.h
     qtwidgets/views/View_qtwidgets.cpp
     qtwidgets/views/View_qtwidgets.h
     qtwidgets/views/ViewWrapper_qtwidgets.cpp

src/Platform.cpp

@@ -0,0 +1,33 @@
+/*
+  This file is part of KDDockWidgets.
+
+  SPDX-FileCopyrightText: 2020-2022 Klarälvdalens Datakonsult AB, a KDAB Group company <info@kdab.com>
+  Author: Sérgio Martins <sergio.martins@kdab.com>
+
+  SPDX-License-Identifier: GPL-2.0-only OR GPL-3.0-only
+
+  Contact KDAB at <info@kdab.com> for commercial licensing options.
+*/
+
+#include "Platform.h"
+#include <qglobal.h>
+#include <QDebug>
+
+using namespace KDDockWidgets;
+
+static Platform *s_platform = nullptr;
+
+Platform::Platform()
+{
+    qDebug() << "Created!";
+    s_platform = this;
+}
+
+Platform::~Platform()
+{
+}
+
+Platform *Platform::instance()
+{
+    return s_platform;
+}

src/Platform.h

@@ -0,0 +1,34 @@
+/*
+  This file is part of KDDockWidgets.
+
+  SPDX-FileCopyrightText: 2020-2022 Klarälvdalens Datakonsult AB, a KDAB Group company <info@kdab.com>
+  Author: Sérgio Martins <sergio.martins@kdab.com>
+
+  SPDX-License-Identifier: GPL-2.0-only OR GPL-3.0-only
+
+  Contact KDAB at <info@kdab.com> for commercial licensing options.
+*/
+
+#pragma once
+
+#include "docks_export.h"
+
+namespace KDDockWidgets {
+
+/// @brief implements functions specific to a particular platform
+/// A platform can be for example qtwidgets, qtquick, etc.
+class DOCKS_EXPORT Platform
+{
+public:
+    virtual ~Platform();
+    /// @brief Returns the name of the platform, only "qtwidgets" and "qtquick"
+    virtual const char *name() const = 0;
+
+    /// @brief Returns the platform singleton
+    static Platform *instance();
+
+protected:
+    Platform();
+};
+
+}

src/private/DockRegistry.cpp

@@ -33,9 +33,7 @@
 #include <QGuiApplication>
 #include <QWindow>
 
-#ifdef KDDOCKWIDGETS_QTWIDGETS
-#include "qtwidgets/DebugWindow_p.h"
-#else
+#ifndef KDDOCKWIDGETS_QTWIDGETS
 #include "quick/QmlTypes.h"
 #endif
 
@@ -57,16 +55,7 @@ DockRegistry::DockRegistry(QObject *parent)
 {
     qApp->installEventFilter(this);
 
-#ifdef KDDOCKWIDGETS_QTWIDGETS
-
-#ifdef DOCKS_DEVELOPER_MODE
-    if (qEnvironmentVariableIntValue("KDDOCKWIDGETS_SHOW_DEBUG_WINDOW") == 1) {
-        auto dv = new Debug::DebugWindow();
-        dv->show();
-    }
-#endif
-
-#else
+#ifndef KDDOCKWIDGETS_QTWIDGETS
     KDDockWidgets::registerQmlTypes();
     QQuickWindow::setDefaultAlphaBuffer(true);
 #endif

src/qtwidgets/Platform_qtwidgets.cpp

@@ -0,0 +1,36 @@
+/*
+  This file is part of KDDockWidgets.
+
+  SPDX-FileCopyrightText: 2020-2022 Klarälvdalens Datakonsult AB, a KDAB Group company <info@kdab.com>
+  Author: Sérgio Martins <sergio.martins@kdab.com>
+
+  SPDX-License-Identifier: GPL-2.0-only OR GPL-3.0-only
+
+  Contact KDAB at <info@kdab.com> for commercial licensing options.
+*/
+
+#include "Platform_qtwidgets.h"
+#include "KDDockWidgets.h"
+
+static KDDockWidgets::Platform_qtwidgets s_platformQtWidgets;
+
+using namespace KDDockWidgets;
+
+Platform_qtwidgets::Platform_qtwidgets()
+{
+#ifdef DOCKS_DEVELOPER_MODE
+    if (qEnvironmentVariableIntValue("KDDOCKWIDGETS_SHOW_DEBUG_WINDOW") == 1) {
+        auto dv = new Debug::DebugWindow();
+        dv->show();
+    }
+#endif
+}
+
+Platform_qtwidgets::~Platform_qtwidgets()
+{
+}
+
+const char *Platform_qtwidgets::name() const
+{
+    return "qtwidgets";
+}

src/qtwidgets/Platform_qtwidgets.h

@@ -0,0 +1,29 @@
+/*
+  This file is part of KDDockWidgets.
+
+  SPDX-FileCopyrightText: 2020-2022 Klarälvdalens Datakonsult AB, a KDAB Group company <info@kdab.com>
+  Author: Sérgio Martins <sergio.martins@kdab.com>
+
+  SPDX-License-Identifier: GPL-2.0-only OR GPL-3.0-only
+
+  Contact KDAB at <info@kdab.com> for commercial licensing options.
+*/
+
+#pragma once
+
+#include "Platform.h"
+#include "qtwidgets/DebugWindow_p.h"
+
+namespace KDDockWidgets {
+
+/// @brief implements functions specific to a particular platform
+/// A platform can be for example qtwidgets, qtquick, etc.
+class DOCKS_EXPORT Platform_qtwidgets : public Platform
+{
+public:
+    Platform_qtwidgets();
+    ~Platform_qtwidgets() override;
+    const char *name() const override;
+};
+
+}