Android: camera moved to a dedicated thread

Actual camera work moved to JCameraWorker which lives in dedicated
thread. JCamera now acts as proxy calling JCameraWorker methods with
invokeMethod (when it is needed).

[ChangeLog][QtMultimedia][Android] camera operations moved to a
dedicated thread

Task-number: QTBUG-35564
Change-Id: Ie4edcbf0869d56b0fef4ad0c820450cc77657fdd
Reviewed-by: Yoann Lopes <yoann.lopes@digia.com>

src/plugins/android/src/mediacapture/qandroidcamerasession.cpp

@@ -182,7 +182,10 @@ bool QAndroidCameraSession::open()
 
     if (m_camera) {
         connect(m_camera, SIGNAL(pictureExposed()), this, SLOT(onCameraPictureExposed()));
+        connect(m_camera, SIGNAL(previewFetched(QByteArray)), this, SLOT(onCameraPreviewFetched(QByteArray)));
         connect(m_camera, SIGNAL(pictureCaptured(QByteArray)), this, SLOT(onCameraPictureCaptured(QByteArray)));
+        connect(m_camera, SIGNAL(previewStarted()), this, SLOT(onCameraPreviewStarted()));
+        connect(m_camera, SIGNAL(previewStopped()), this, SLOT(onCameraPreviewStopped()));
 
         m_nativeOrientation = m_camera->getNativeOrientation();
 
@@ -309,11 +312,6 @@ void QAndroidCameraSession::startPreview()
 
     m_camera->startPreview();
     m_previewStarted = true;
-
-    m_status = QCamera::ActiveStatus;
-    emit statusChanged(m_status);
-
-    setReadyForCapture(true);
 }
 
 void QAndroidCameraSession::stopPreview()
@@ -331,11 +329,6 @@ void QAndroidCameraSession::stopPreview()
     if (m_videoOutput)
         m_videoOutput->stop();
     m_previewStarted = false;
-
-    m_status = QCamera::LoadedStatus;
-    emit statusChanged(m_status);
-
-    setReadyForCapture(false);
 }
 
 void QAndroidCameraSession::setImageSettings(const QImageEncoderSettings &settings)
@@ -507,11 +500,15 @@ void QAndroidCameraSession::onCameraPictureExposed()
         return;
 
     emit imageExposed(m_currentImageCaptureId);
-    QByteArray lastFrame = m_camera->fetchLastPreviewFrame();
-    if (lastFrame.size()) {
+    m_camera->fetchLastPreviewFrame();
+}
+
+void QAndroidCameraSession::onCameraPreviewFetched(const QByteArray &preview)
+{
+    if (preview.size()) {
         QtConcurrent::run(this, &QAndroidCameraSession::processPreviewImage,
                           m_currentImageCaptureId,
-                          lastFrame,
+                          preview,
                           m_camera->getRotation());
     }
 }
@@ -532,10 +529,28 @@ void QAndroidCameraSession::onCameraPictureCaptured(const QByteArray &data)
 
     // Preview needs to be restarted after taking a picture
     m_camera->startPreview();
+}
+
+void QAndroidCameraSession::onCameraPreviewStarted()
+{
+    if (m_status == QCamera::StartingStatus) {
+        m_status = QCamera::ActiveStatus;
+        emit statusChanged(m_status);
+    }
 
     setReadyForCapture(true);
 }
 
+void QAndroidCameraSession::onCameraPreviewStopped()
+{
+    if (m_status == QCamera::StoppingStatus) {
+        m_status = QCamera::LoadedStatus;
+        emit statusChanged(m_status);
+    }
+
+    setReadyForCapture(false);
+}
+
 void QAndroidCameraSession::processCapturedImage(int id,
                                                  const QByteArray &data,
                                                  const QSize &resolution,

src/plugins/android/src/mediacapture/qandroidcamerasession.h

@@ -113,7 +113,10 @@ private Q_SLOTS:
     void onApplicationStateChanged(Qt::ApplicationState state);
 
     void onCameraPictureExposed();
+    void onCameraPreviewFetched(const QByteArray &preview);
     void onCameraPictureCaptured(const QByteArray &data);
+    void onCameraPreviewStarted();
+    void onCameraPreviewStopped();
 
 private:
     bool open();

src/plugins/android/src/wrappers/jcamera.h

@@ -49,9 +49,15 @@
 
 QT_BEGIN_NAMESPACE
 
-class JCamera : public QObject, public QJNIObjectPrivate
+class QThread;
+
+class JCameraWorker;
+
+class JCamera : public QObject
 {
     Q_OBJECT
+    Q_ENUMS(CameraFacing)
+    Q_ENUMS(ImageFormat)
 public:
     enum CameraFacing {
         CameraFacingBack = 0,
@@ -72,7 +78,7 @@ public:
 
     static JCamera *open(int cameraId);
 
-    int cameraId() const { return m_cameraId; }
+    int cameraId() const;
 
     void lock();
     void unlock();
@@ -90,7 +96,7 @@ public:
     ImageFormat getPreviewFormat();
     void setPreviewFormat(ImageFormat fmt);
 
-    QSize previewSize() const { return m_previewSize; }
+    QSize previewSize() const;
     void setPreviewSize(const QSize &size);
     void setPreviewTexture(jobject surfaceTexture);
 
@@ -149,12 +155,15 @@ public:
 
     void takePicture();
 
-    QByteArray fetchLastPreviewFrame();
+    void fetchLastPreviewFrame();
+    QJNIObjectPrivate getCameraObject();
 
     static bool initJNI(JNIEnv *env);
 
 Q_SIGNALS:
     void previewSizeChanged();
+    void previewStarted();
+    void previewStopped();
 
     void autoFocusStarted();
     void autoFocusComplete(bool success);
@@ -163,21 +172,12 @@ Q_SIGNALS:
 
     void pictureExposed();
     void pictureCaptured(const QByteArray &data);
+    void previewFetched(const QByteArray &preview);
 
 private:
-    JCamera(int cameraId, jobject cam);
-    void applyParameters();
+    JCamera(int cameraId, jobject cam, QThread *workerThread);
 
-    QStringList callStringListMethod(const char *methodName);
-
-    int m_cameraId;
-    QJNIObjectPrivate m_info;
-    QJNIObjectPrivate m_parameters;
-
-    QSize m_previewSize;
-    int m_rotation;
-
-    bool m_hasAPI14;
+    JCameraWorker *d;
 };
 
 QT_END_NAMESPACE

src/plugins/android/src/wrappers/jmediarecorder.cpp

@@ -151,7 +151,7 @@ void JMediaRecorder::setAudioSource(AudioSource source)
 
 void JMediaRecorder::setCamera(JCamera *camera)
 {
-    QJNIObjectPrivate cam = camera->getObjectField("m_camera", "Landroid/hardware/Camera;");
+    QJNIObjectPrivate cam = camera->getCameraObject();
     callMethod<void>("setCamera", "(Landroid/hardware/Camera;)V", cam.object());
 }