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>

5 files changed, 440 insertions, 79 deletions

diff --git a/src/plugins/resourcepolicy/resourcepolicy.pro b/src/plugins/resourcepolicy/resourcepolicy.pro
index 7aa1ced9f..4805c5250 100644
--- a/src/plugins/resourcepolicy/resourcepolicy.pro
+++ b/src/plugins/resourcepolicy/resourcepolicy.pro
@@ -13,9 +13,11 @@ INCLUDEPATH += $$PWD \
 
 HEADERS += \
     $$PWD/resourcepolicyplugin.h \
-    $$PWD/resourcepolicyimpl.h
+    $$PWD/resourcepolicyimpl.h \
+    $$PWD/resourcepolicyint.h
 
 SOURCES += \
     $$PWD/resourcepolicyplugin.cpp \
-    $$PWD/resourcepolicyimpl.cpp
+    $$PWD/resourcepolicyimpl.cpp \
+    $$PWD/resourcepolicyint.cpp
 
diff --git a/src/plugins/resourcepolicy/resourcepolicyimpl.cpp b/src/plugins/resourcepolicy/resourcepolicyimpl.cpp
index 0acabc001..3ad92fa1f 100644
--- a/src/plugins/resourcepolicy/resourcepolicyimpl.cpp
+++ b/src/plugins/resourcepolicy/resourcepolicyimpl.cpp
@@ -40,99 +40,62 @@
 **
 ****************************************************************************/
 
+#include <QGlobalStatic>
+
 #include <policy/resource.h>
 #include <policy/resources.h>
 #include <policy/resource-set.h>
 
 #include "resourcepolicyimpl.h"
+#include "resourcepolicyint.h"
+
+Q_GLOBAL_STATIC(ResourcePolicyInt, globalResourcePolicyInt);
 
 ResourcePolicyImpl::ResourcePolicyImpl(QObject *parent)
     : QMediaPlayerResourceSetInterface(parent)
-    , m_status(Initial)
-    , m_videoEnabled(false)
 {
-    m_resourceSet = new ResourcePolicy::ResourceSet("player", this);
-    m_resourceSet->setAlwaysReply();
-
-    ResourcePolicy::AudioResource *audioResource = new ResourcePolicy::AudioResource("player");
-    audioResource->setProcessID(QCoreApplication::applicationPid());
-    audioResource->setStreamTag("media.name", "*");
-    m_resourceSet->addResourceObject(audioResource);
-
-    m_resourceSet->update();
+    ResourcePolicyInt *set = globalResourcePolicyInt;
+    set->addClient(this);
+}
 
-    connect(m_resourceSet, SIGNAL(resourcesGranted(QList<ResourcePolicy::ResourceType>)),
-            this, SLOT(handleResourcesGranted()));
-    connect(m_resourceSet, SIGNAL(resourcesDenied()),
-            this, SLOT(handleResourcesDenied()));
-    connect(m_resourceSet, SIGNAL(lostResources()),
-            this, SLOT(handleResourcesLost()));
-    connect(m_resourceSet, SIGNAL(resourcesReleasedByManager()),
-            this, SLOT(handleResourcesLost()));
+ResourcePolicyImpl::~ResourcePolicyImpl()
+{
+    ResourcePolicyInt *set = globalResourcePolicyInt;
+    set->removeClient(this);
 }
 
 bool ResourcePolicyImpl::isVideoEnabled() const
 {
-    return m_videoEnabled;
+    ResourcePolicyInt *set = globalResourcePolicyInt;
+    return set->isVideoEnabled(this);
 }
 
 void ResourcePolicyImpl::setVideoEnabled(bool videoEnabled)
 {
-    if (m_videoEnabled != videoEnabled) {
-        m_videoEnabled = videoEnabled;
-
-        if (videoEnabled)
-            m_resourceSet->addResource(ResourcePolicy::VideoPlaybackType);
-        else
-            m_resourceSet->deleteResource(ResourcePolicy::VideoPlaybackType);
-
-        m_resourceSet->update();
-    }
+    ResourcePolicyInt *set = globalResourcePolicyInt;
+    set->setVideoEnabled(this, videoEnabled);
 }
 
 void ResourcePolicyImpl::acquire()
 {
-    m_status = RequestedResource;
-    m_resourceSet->acquire();
+    ResourcePolicyInt *set = globalResourcePolicyInt;
+    set->acquire(this);
 }
 
 void ResourcePolicyImpl::release()
 {
-    m_resourceSet->release();
-    m_status = Initial;
+    ResourcePolicyInt *set = globalResourcePolicyInt;
+    set->release(this);
 }
 
 bool ResourcePolicyImpl::isGranted() const
 {
-    return m_status == GrantedResource;
+    ResourcePolicyInt *set = globalResourcePolicyInt;
+    return set->isGranted(this);
 }
 
 bool ResourcePolicyImpl::isAvailable() const
 {
-    // TODO: is this used? what is it for?
-    qWarning() << Q_FUNC_INFO << "Stub";
-    return true;
+    ResourcePolicyInt *set = globalResourcePolicyInt;
+    return set->isAvailable();
 }
-
-void ResourcePolicyImpl::handleResourcesGranted()
-{
-    m_status = GrantedResource;
-    emit resourcesGranted();
-}
-
-void ResourcePolicyImpl::handleResourcesDenied()
-{
-    m_status = Initial;
-    emit resourcesDenied();
-}
-
-void ResourcePolicyImpl::handleResourcesLost()
-{
-    if (m_status != Initial) {
-        m_status = Initial;
-        emit resourcesLost();
-    }
-
-    m_resourceSet->release();
-}
-
diff --git a/src/plugins/resourcepolicy/resourcepolicyimpl.h b/src/plugins/resourcepolicy/resourcepolicyimpl.h
index 8680df86a..28393b789 100644
--- a/src/plugins/resourcepolicy/resourcepolicyimpl.h
+++ b/src/plugins/resourcepolicy/resourcepolicyimpl.h
@@ -56,6 +56,7 @@ class ResourcePolicyImpl : public QMediaPlayerResourceSetInterface
     Q_OBJECT
 public:
     ResourcePolicyImpl(QObject *parent = 0);
+    ~ResourcePolicyImpl();
 
     bool isVideoEnabled() const;
     void setVideoEnabled(bool videoEnabled);
@@ -63,22 +64,6 @@ public:
     void release();
     bool isGranted() const;
     bool isAvailable() const;
-
-private slots:
-    void handleResourcesGranted();
-    void handleResourcesDenied();
-    void handleResourcesLost();
-
-private:
-    enum ResourceStatus {
-        Initial = 0,
-        RequestedResource,
-        GrantedResource
-    };
-
-    bool m_videoEnabled;
-    ResourcePolicy::ResourceSet *m_resourceSet;
-    ResourceStatus m_status;
 };
 
 #endif // RESOURCEPOLICYIMPL_H
diff --git a/src/plugins/resourcepolicy/resourcepolicyint.cpp b/src/plugins/resourcepolicy/resourcepolicyint.cpp
new file mode 100644
index 000000000..2fff64bfb
--- /dev/null
+++ b/src/plugins/resourcepolicy/resourcepolicyint.cpp
@@ -0,0 +1,311 @@
+/****************************************************************************
+**
+** 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.
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+
+#include <policy/resource.h>
+#include <policy/resources.h>
+#include <policy/resource-set.h>
+
+#include "resourcepolicyint.h"
+#include "resourcepolicyimpl.h"
+
+#include <QMap>
+
+static int clientid = 0;
+
+ResourcePolicyInt::ResourcePolicyInt(QObject *parent)
+    : QObject(parent)
+    , m_acquired(0)
+    , m_status(Initial)
+    , m_video(0)
+    , m_resourceSet(0)
+{
+    m_resourceSet = new ResourcePolicy::ResourceSet("player", this);
+    m_resourceSet->setAlwaysReply();
+
+    ResourcePolicy::AudioResource *audioResource = new ResourcePolicy::AudioResource("player");
+    audioResource->setProcessID(QCoreApplication::applicationPid());
+    audioResource->setStreamTag("media.name", "*");
+    m_resourceSet->addResourceObject(audioResource);
+
+    m_resourceSet->update();
+
+    connect(m_resourceSet, SIGNAL(resourcesGranted(QList<ResourcePolicy::ResourceType>)),
+            this, SLOT(handleResourcesGranted()));
+    connect(m_resourceSet, SIGNAL(resourcesDenied()),
+            this, SLOT(handleResourcesDenied()));
+    connect(m_resourceSet, SIGNAL(lostResources()),
+            this, SLOT(handleResourcesLost()));
+    connect(m_resourceSet, SIGNAL(resourcesReleasedByManager()),
+            this, SLOT(handleResourcesLost()));
+}
+
+ResourcePolicyInt::~ResourcePolicyInt()
+{
+    delete m_resourceSet;
+    m_resourceSet = 0;
+#ifdef RESOURCE_DEBUG
+    qDebug() << "##### Tearing down singleton.";
+#endif
+}
+
+void ResourcePolicyInt::addClient(ResourcePolicyImpl *client)
+{
+    clientEntry entry;
+    entry.id = clientid++;
+    entry.client = client;
+    entry.status = Initial;
+    entry.videoEnabled = false;
+    m_clients.insert(entry.client, entry);
+#ifdef RESOURCE_DEBUG
+    qDebug() << "##### Add client " << client << " : " << entry.id;
+#endif
+}
+
+void ResourcePolicyInt::removeClient(ResourcePolicyImpl *client)
+{
+    QMap<const ResourcePolicyImpl*, clientEntry>::iterator i = m_clients.find(client);
+    if (i != m_clients.end()) {
+#ifdef RESOURCE_DEBUG
+        qDebug() << "##### Remove client " << client << " : " << i.value().id;
+#endif
+        if (i.value().status == GrantedResource)
+            --m_acquired;
+        m_clients.erase(i);
+    }
+
+    if (m_acquired == 0) {
+#ifdef RESOURCE_DEBUG
+        qDebug() << "##### Remove client, acquired = 0, release";
+#endif
+        m_resourceSet->release();
+        m_status = Initial;
+    }
+}
+
+bool ResourcePolicyInt::isVideoEnabled(const ResourcePolicyImpl *client) const
+{
+    QMap<const ResourcePolicyImpl*, clientEntry>::const_iterator i = m_clients.find(client);
+    if (i != m_clients.constEnd())
+        return i.value().videoEnabled;
+
+    return false;
+}
+
+void ResourcePolicyInt::setVideoEnabled(const ResourcePolicyImpl *client, bool videoEnabled)
+{
+    bool update = false;
+
+    QMap<const ResourcePolicyImpl*, clientEntry>::iterator i = m_clients.find(client);
+    if (i != m_clients.end()) {
+        if (videoEnabled == i.value().videoEnabled)
+            return;
+
+        if (videoEnabled) {
+            if (m_video > 0) {
+                i.value().videoEnabled = true;
+            } else {
+                m_resourceSet->addResource(ResourcePolicy::VideoPlaybackType);
+                update = true;
+            }
+            ++m_video;
+        } else {
+            --m_video;
+            i.value().videoEnabled = false;
+            if (m_video == 0) {
+                m_resourceSet->deleteResource(ResourcePolicy::VideoPlaybackType);
+                update = true;
+            }
+        }
+    }
+
+    if (update)
+        m_resourceSet->update();
+}
+
+void ResourcePolicyInt::acquire(const ResourcePolicyImpl *client)
+{
+    QMap<const ResourcePolicyImpl*, clientEntry>::iterator i = m_clients.find(client);
+    if (i != m_clients.end()) {
+#ifdef RESOURCE_DEBUG
+        qDebug() << "##### " << i.value().id << ": ACQUIRE";
+#endif
+        if (i.value().status == Initial) {
+
+            if (m_status == RequestedResource) {
+                i.value().status = RequestedResource;
+#ifdef RESOURCE_DEBUG
+                qDebug() << "##### " << i.value().id << ": Already requesting, set client as RequestResource and return";
+#endif
+                return;
+            }
+
+            if (m_status == GrantedResource) {
+                ++m_acquired;
+#ifdef RESOURCE_DEBUG
+                qDebug() << "##### " << i.value().id << ": Already granted, set as GrantedResource and return";
+#endif
+                i.value().status = GrantedResource;
+                emit i.value().client->resourcesGranted();
+                return;
+            }
+        } else if (i.value().status == RequestedResource) {
+#ifdef RESOURCE_DEBUG
+            qDebug() << "##### " << i.value().id << ": Already requesting, return";
+#endif
+            return;
+        } else {
+#ifdef RESOURCE_DEBUG
+            qDebug() << "##### " << i.value().id << ": Already granted, return ";
+#endif
+            return;
+        }
+        i.value().status = RequestedResource;
+        m_status = RequestedResource;
+
+#ifdef RESOURCE_DEBUG
+        qDebug() << "##### " << i.value().id << ": ACQUIRE call resourceSet->acquire()";
+#endif
+        // If m_status was Initial this is the first time resources are requested,
+        // so let's actually do the acquiring
+        m_resourceSet->acquire();
+    }
+}
+
+void ResourcePolicyInt::release(const ResourcePolicyImpl *client)
+{
+    QMap<const ResourcePolicyImpl*, clientEntry>::iterator i = m_clients.find(client);
+    if (i != m_clients.end()) {
+        if (i.value().status == GrantedResource) {
+            i.value().status = Initial;
+            --m_acquired;
+#ifdef RESOURCE_DEBUG
+            qDebug() << "##### " << i.value().id << ": RELEASE, acquired (" << m_acquired << ")";
+#endif
+        }
+    }
+
+    if (m_acquired == 0) {
+#ifdef RESOURCE_DEBUG
+        qDebug() << "##### " << i.value().id << ": RELEASE call resourceSet->release()";
+#endif
+        m_resourceSet->release();
+        m_status = Initial;
+    }
+}
+
+bool ResourcePolicyInt::isGranted(const ResourcePolicyImpl *client) const
+{
+    QMap<const ResourcePolicyImpl*, clientEntry>::const_iterator i = m_clients.find(client);
+    if (i != m_clients.constEnd()) {
+#ifdef RESOURCE_DEBUG
+            qDebug() << "##### " << i.value().id << ": IS GRANTED, status: " << i.value().status;
+#endif
+        return i.value().status == GrantedResource;
+    }
+
+    return false;
+}
+
+bool ResourcePolicyInt::isAvailable() const
+{
+    // TODO: is this used? what is it for?
+    qWarning() << Q_FUNC_INFO << "Stub";
+    return true;
+}
+
+void ResourcePolicyInt::handleResourcesGranted()
+{
+    m_status = GrantedResource;
+    QMap<const ResourcePolicyImpl*, clientEntry>::iterator i = m_clients.begin();
+    while (i != m_clients.end()) {
+        if (i.value().status == RequestedResource) {
+            ++m_acquired;
+#ifdef RESOURCE_DEBUG
+            qDebug() << "##### " << i.value().id << ": HANDLE GRANTED, acquired (" << m_acquired << ") emitting resourcesGranted()";
+#endif
+            i.value().status = GrantedResource;
+            emit i.value().client->resourcesGranted();
+        }
+        ++i;
+    }
+}
+
+void ResourcePolicyInt::handleResourcesDenied()
+{
+    m_status = Initial;
+    m_acquired = 0;
+    QMap<const ResourcePolicyImpl*, clientEntry>::iterator i = m_clients.begin();
+    while (i != m_clients.end()) {
+        if (i.value().status == RequestedResource) {
+#ifdef RESOURCE_DEBUG
+            qDebug() << "##### " << i.value().id << ": HANDLE DENIED, acquired (" << m_acquired << ") emitting resourcesDenied()";
+#endif
+            i.value().status = Initial;
+            emit i.value().client->resourcesDenied();
+        }
+        // Do we need to act for clients that are in granted state?
+        ++i;
+    }
+}
+
+void ResourcePolicyInt::handleResourcesLost()
+{
+    if (m_status != Initial) {
+        m_status = Initial;
+    }
+
+    m_acquired = 0;
+    m_resourceSet->release();
+
+    QMap<const ResourcePolicyImpl*, clientEntry>::iterator i = m_clients.begin();
+    while (i != m_clients.end()) {
+        if (i.value().status != Initial) {
+#ifdef RESOURCE_DEBUG
+            qDebug() << "##### " << i.value().id << ": HANDLE LOST, acquired (" << m_acquired << ") emitting resourcesLost()";
+#endif
+            i.value().status = Initial;
+            emit i.value().client->resourcesLost();
+        }
+        ++i;
+    }
+}
diff --git a/src/plugins/resourcepolicy/resourcepolicyint.h b/src/plugins/resourcepolicy/resourcepolicyint.h
new file mode 100644
index 000000000..39882b527
--- /dev/null
+++ b/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