Input: add utils header with helpers

Provides a getter to retrieve a backend physical device from an input class.
The getter handles the case where the physical device is just a wrapper proxy
around a real physical device.

Change-Id: I83814a1c456b62b590697ebd4ec81751b2bfd8ba
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>

2 files changed, 105 insertions, 1 deletions

diff --git a/src/input/backend/backend.pri b/src/input/backend/backend.pri
index 3288b4d3c..846fb1705 100644
--- a/src/input/backend/backend.pri
+++ b/src/input/backend/backend.pri
@@ -33,7 +33,8 @@ HEADERS += \
     $$PWD/eventsourcesetterhelper_p.h \
     $$PWD/job_common_p.h \
     $$PWD/physicaldeviceproxy_p.h \
-    $$PWD/loadproxydevicejob_p.h
+    $$PWD/loadproxydevicejob_p.h \
+    $$PWD/utils_p.h
 
 SOURCES += \
     $$PWD/keyboarddevice.cpp \
diff --git a/src/input/backend/utils_p.h b/src/input/backend/utils_p.h
new file mode 100644
index 000000000..65363ab0a
--- /dev/null
+++ b/src/input/backend/utils_p.h
@@ -0,0 +1,103 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 Klaralvdalens Datakonsult AB (KDAB).
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the Qt3D module 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 QT3DINPUT_INPUT_UTILS_P_H
+#define QT3DINPUT_INPUT_UTILS_P_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists for the convenience
+// of other Qt classes.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include <Qt3DInput/private/inputhandler_p.h>
+#include <Qt3DInput/private/inputmanagers_p.h>
+#include <Qt3DInput/private/physicaldeviceproxy_p.h>
+#include <Qt3DInput/private/qinputdeviceintegration_p.h>
+#include <Qt3DInput/private/qabstractphysicaldevicebackendnode_p.h>
+
+QT_BEGIN_NAMESPACE
+
+namespace Qt3DInput {
+
+namespace Input {
+
+namespace Utils {
+
+template<class InputClass>
+QAbstractPhysicalDeviceBackendNode *physicalDeviceForInput(InputClass *input, InputHandler *handler)
+{
+    // Note: the source device can be a proxy
+    // in which case sourceDeviceId should be the proxy's device id
+    Qt3DCore::QNodeId sourceDeviceId = input->sourceDevice();
+
+    {
+        PhysicalDeviceProxy *deviceProxy = nullptr;
+        if ((deviceProxy = handler->physicalDeviceProxyManager()->lookupResource(sourceDeviceId)) != nullptr)
+            sourceDeviceId = deviceProxy->physicalDeviceId();
+    }
+
+    // Early return if the sourceDeviceId is null
+    if (!sourceDeviceId.isNull()) {
+        const auto integrations = handler->inputDeviceIntegrations();
+        for (QInputDeviceIntegration *integration : integrations) {
+            QAbstractPhysicalDeviceBackendNode *physicalDeviceBackend = integration->physicalDevice(sourceDeviceId);
+            if (physicalDeviceBackend)
+                return physicalDeviceBackend;
+        }
+    }
+
+    return nullptr;
+}
+
+} // Utils
+
+} // Input
+
+} // Qt3DInput
+
+QT_END_NAMESPACE
+
+
+#endif // QT3DINPUT_INPUT_UTILS_P_H