Handle resource requests through singleton.

Many applications have multiple objects dealing with audio, and each
needs to request audio resources from resource policy manager. Resource
policy manager handles audio resources per-manager. Each ResourceSet
instance creates new manager, which causes applications having multiple
audio objects to fight for the audio resources internally, even though
the streams are played from the same process id.

To overcome this in QtMultimedia applications, handle all ResourceSet
operations through singleton. This way one client has only one manager
id registered, and resource acquiring and releasing can be limited to
only when no resources are acquired or all resources are freed. To
reduce unnecessary noise from resource policy plugin to the clients,
keep track of client states and only notify clients which themselves
request for resources etc.

Change-Id: Ifa4488a9f6298a3f601399e9d339f7bd819be757
Done-with: Juho Hämäläinen <juho.hamalainen@tieto.com>
Reviewed-by: Yoann Lopes <yoann.lopes@digia.com>

src/plugins/resourcepolicy/resourcepolicyint.h

@@ -0,0 +1,100 @@
+/****************************************************************************
+**
+** Copyright (C) 2013 Jolla Ltd, author: <robin.burchell@jollamobile.com>
+** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part 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 Digia.  For licensing terms and
+** conditions see http://qt.digia.com/licensing.  For further information
+** use the contact form at http://qt.digia.com/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 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights.  These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef RESOURCEPOLICYINT_H
+#define RESOURCEPOLICYINT_H
+
+#include <QObject>
+#include <QMap>
+
+#include <private/qmediaresourceset_p.h>
+#include "resourcepolicyimpl.h"
+
+namespace ResourcePolicy {
+    class ResourceSet;
+};
+
+enum ResourceStatus {
+    Initial = 0,
+    RequestedResource,
+    GrantedResource
+};
+
+struct clientEntry {
+    int id;
+    ResourcePolicyImpl *client;
+    ResourceStatus status;
+    bool videoEnabled;
+};
+
+class ResourcePolicyInt : public QObject
+{
+    Q_OBJECT
+public:
+    ResourcePolicyInt(QObject *parent = 0);
+    ~ResourcePolicyInt();
+
+    bool isVideoEnabled(const ResourcePolicyImpl *client) const;
+    void setVideoEnabled(const ResourcePolicyImpl *client, bool videoEnabled);
+    void acquire(const ResourcePolicyImpl *client);
+    void release(const ResourcePolicyImpl *client);
+    bool isGranted(const ResourcePolicyImpl *client) const;
+    bool isAvailable() const;
+
+    void addClient(ResourcePolicyImpl *client);
+    void removeClient(ResourcePolicyImpl *client);
+
+private slots:
+    void handleResourcesGranted();
+    void handleResourcesDenied();
+    void handleResourcesLost();
+
+private:
+    QMap<const ResourcePolicyImpl*, clientEntry> m_clients;
+
+    int m_acquired;
+    ResourceStatus m_status;
+    int m_video;
+    ResourcePolicy::ResourceSet *m_resourceSet;
+};
+
+#endif // RESOURCEPOLICYINT_H