Prettify calling of QMediaDevice signals

The idea is inheriting QPlatformMediaDevices from QObject and
connect it to QMediaDevice instances instead of manual collecting
and managing pointers.

Advantages:
- avoid UB behavior with static object destruction order in case
  a user makes any QMediaDevices static.
- align the signals parent: send singals from the QMediaDevice instance

Pick-to: 6.5 6.6
Task-number: QTBUG-110071
Change-Id: I7c30694210864ff8c6c90c7299abdbf383f398fa
Reviewed-by: Pavel Dubsky <pavel.dubsky@qt.io>
Reviewed-by: Lars Knoll <lars@knoll.priv.no>
Reviewed-by: Jøger Hansegård <joger.hansegard@qt.io>

3 files changed, 11 insertions, 43 deletions

diff --git a/src/multimedia/platform/qplatformmediadevices.cpp b/src/multimedia/platform/qplatformmediadevices.cpp
index 95cf3b7a0..09c26a670 100644
--- a/src/multimedia/platform/qplatformmediadevices.cpp
+++ b/src/multimedia/platform/qplatformmediadevices.cpp
@@ -132,27 +132,8 @@ QPlatformAudioSink *QPlatformMediaDevices::audioOutputDevice(const QAudioFormat
     return p;
 }
 
-void QPlatformMediaDevices::audioInputsChanged() const
-{
-    const auto devices = allMediaDevices();
-    for (auto m : devices)
-        emit m->audioInputsChanged();
-}
-
-void QPlatformMediaDevices::audioOutputsChanged() const
-{
-    const auto devices = allMediaDevices();
-    for (auto m : devices)
-        emit m->audioOutputsChanged();
-}
-
-void QPlatformMediaDevices::videoInputsChanged() const
-{
-    const auto devices = allMediaDevices();
-    for (auto m : devices)
-        emit m->videoInputsChanged();
-}
-
 void QPlatformMediaDevices::prepareAudio() { }
 
 QT_END_NAMESPACE
+
+#include "moc_qplatformmediadevices_p.cpp"
diff --git a/src/multimedia/platform/qplatformmediadevices_p.h b/src/multimedia/platform/qplatformmediadevices_p.h
index 9b8d0d5e7..d475495d1 100644
--- a/src/multimedia/platform/qplatformmediadevices_p.h
+++ b/src/multimedia/platform/qplatformmediadevices_p.h
@@ -17,10 +17,10 @@
 
 #include <private/qtmultimediaglobal_p.h>
 #include <qlist.h>
+#include <qobject.h>
 
 QT_BEGIN_NAMESPACE
 
-class QObject;
 class QMediaDevices;
 class QAudioDevice;
 class QCameraDevice;
@@ -29,11 +29,12 @@ class QPlatformAudioSink;
 class QAudioFormat;
 class QPlatformMediaIntegration;
 
-class Q_MULTIMEDIA_EXPORT QPlatformMediaDevices
+class Q_MULTIMEDIA_EXPORT QPlatformMediaDevices : public QObject
 {
+    Q_OBJECT
 public:
     QPlatformMediaDevices();
-    virtual ~QPlatformMediaDevices();
+    ~QPlatformMediaDevices() override;
 
     static void setDevices(QPlatformMediaDevices *);
     static QPlatformMediaDevices *instance();
@@ -49,26 +50,12 @@ public:
     QPlatformAudioSink *audioOutputDevice(const QAudioFormat &format,
                                           const QAudioDevice &deviceInfo, QObject *parent);
 
-    void addMediaDevices(QMediaDevices *m)
-    {
-        m_devices.append(m);
-    }
-    void removeMediaDevices(QMediaDevices *m)
-    {
-        m_devices.removeAll(m);
-    }
-
-    QList<QMediaDevices *> allMediaDevices() const { return m_devices; }
-
-    void videoInputsChanged() const;
-
     virtual void prepareAudio();
 
-protected:
-    void audioInputsChanged() const;
-    void audioOutputsChanged() const;
-
-    QList<QMediaDevices *> m_devices;
+Q_SIGNALS:
+    void audioInputsChanged();
+    void audioOutputsChanged();
+    void videoInputsChanged();
 };
 
 QT_END_NAMESPACE
diff --git a/src/multimedia/platform/qplatformvideodevices.cpp b/src/multimedia/platform/qplatformvideodevices.cpp
index 9d2fc3c31..e556bb899 100644
--- a/src/multimedia/platform/qplatformvideodevices.cpp
+++ b/src/multimedia/platform/qplatformvideodevices.cpp
@@ -13,7 +13,7 @@ QPlatformVideoDevices::~QPlatformVideoDevices()
 
 void QPlatformVideoDevices::videoInputsChanged()
 {
-    QPlatformMediaDevices::instance()->videoInputsChanged();
+    emit QPlatformMediaDevices::instance()->videoInputsChanged();
 }
 
 QT_END_NAMESPACE