qcam: Queue requests only through MainWindow::queueRequest()

Currently to request a frame, we operate the camera directly.
This approach is also scattered in two places,
MainWindow::startCapture() and MainWindow::queueRequest().
This makes it difficult to account for requests.

Centralize all the queuing to a single function queueRequest()

Rename the current queueRequest() to renderComplete().
This makes more sense as this slot is triggered when
the render is complete and we want to queue another
request.

Signed-off-by: Utkarsh Tiwari <utkarsh02t@gmail.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Umang Jain <umang.jain@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

src/qcam/main_window.cpp

@@ -119,14 +119,14 @@ MainWindow::MainWindow(CameraManager *cm, const OptionsParser::Options &options)
 	if (renderType == "qt") {
 		ViewFinderQt *viewfinder = new ViewFinderQt(this);
 		connect(viewfinder, &ViewFinderQt::renderComplete,
-			this, &MainWindow::queueRequest);
+			this, &MainWindow::renderComplete);
 		viewfinder_ = viewfinder;
 		setCentralWidget(viewfinder);
 #ifndef QT_NO_OPENGL
 	} else if (renderType == "gles") {
 		ViewFinderGL *viewfinder = new ViewFinderGL(this);
 		connect(viewfinder, &ViewFinderGL::renderComplete,
-			this, &MainWindow::queueRequest);
+			this, &MainWindow::renderComplete);
 		viewfinder_ = viewfinder;
 		setCentralWidget(viewfinder);
 #endif
@@ -517,7 +517,7 @@ int MainWindow::startCapture()
 
 	/* Queue all requests. */
 	for (std::unique_ptr<Request> &request : requests_) {
-		ret = camera_->queueRequest(request.get());
+		ret = queueRequest(request.get());
 		if (ret < 0) {
 			qWarning() << "Can't queue request";
 			goto error_disconnect;
@@ -750,7 +750,7 @@ void MainWindow::processViewfinder(FrameBuffer *buffer)
 	viewfinder_->render(buffer, mappedBuffers_[buffer].get());
 }
 
-void MainWindow::queueRequest(FrameBuffer *buffer)
+void MainWindow::renderComplete(FrameBuffer *buffer)
 {
 	Request *request;
 	{
@@ -779,6 +779,10 @@ void MainWindow::queueRequest(FrameBuffer *buffer)
 			qWarning() << "No free buffer available for RAW capture";
 		}
 	}
-
-	camera_->queueRequest(request);
+	queueRequest(request);
+}
+
+int MainWindow::queueRequest(Request *request)
+{
+	return camera_->queueRequest(request);
 }

src/qcam/main_window.h

@@ -68,7 +68,7 @@ private Q_SLOTS:
 	void processRaw(libcamera::FrameBuffer *buffer,
 			const libcamera::ControlList &metadata);
 
-	void queueRequest(libcamera::FrameBuffer *buffer);
+	void renderComplete(libcamera::FrameBuffer *buffer);
 
 private:
 	int createToolbars();
@@ -82,6 +82,7 @@ private:
 	void addCamera(std::shared_ptr<libcamera::Camera> camera);
 	void removeCamera(std::shared_ptr<libcamera::Camera> camera);
 
+	int queueRequest(libcamera::Request *request);
 	void requestComplete(libcamera::Request *request);
 	void processCapture();
 	void processHotplug(HotplugEvent *e);