libcamera, android, cam, gstreamer, qcam, v4l2: Reuse Request

Allow reuse of the Request object by implementing reuse(). This means
the applications now have the responsibility of freeing the Request
objects, so make all libcamera users (cam, qcam, v4l2-compat, gstreamer,
android) do so.

Signed-off-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>

2 files changed, 31 insertions, 37 deletions

diff --git a/src/qcam/main_window.cpp b/src/qcam/main_window.cpp
index ecb9dd66..0cbdab9a 100644
--- a/src/qcam/main_window.cpp
+++ b/src/qcam/main_window.cpp
@@ -367,7 +367,6 @@ void MainWindow::toggleCapture(bool start)
 int MainWindow::startCapture()
 {
 	StreamRoles roles = StreamKeyValueParser::roles(options_[OptStream]);
-	std::vector<Request *> requests;
 	int ret;
 
 	/* Verify roles are supported. */
@@ -486,7 +485,7 @@ int MainWindow::startCapture()
 	while (!freeBuffers_[vfStream_].isEmpty()) {
 		FrameBuffer *buffer = freeBuffers_[vfStream_].dequeue();
 
-		Request *request = camera_->createRequest();
+		std::unique_ptr<Request> request = camera_->createRequest();
 		if (!request) {
 			qWarning() << "Can't create request";
 			ret = -ENOMEM;
@@ -499,7 +498,7 @@ int MainWindow::startCapture()
 			goto error;
 		}
 
-		requests.push_back(request);
+		requests_.push_back(std::move(request));
 	}
 
 	/* Start the title timer and the camera. */
@@ -518,8 +517,8 @@ int MainWindow::startCapture()
 	camera_->requestCompleted.connect(this, &MainWindow::requestComplete);
 
 	/* Queue all requests. */
-	for (Request *request : requests) {
-		ret = camera_->queueRequest(request);
+	for (std::unique_ptr<Request> &request : requests_) {
+		ret = camera_->queueRequest(request.get());
 		if (ret < 0) {
 			qWarning() << "Can't queue request";
 			goto error_disconnect;
@@ -535,8 +534,7 @@ error_disconnect:
 	camera_->stop();
 
 error:
-	for (Request *request : requests)
-		delete request;
+	requests_.clear();
 
 	for (auto &iter : mappedBuffers_) {
 		const MappedBuffer &buffer = iter.second;
@@ -580,6 +578,8 @@ void MainWindow::stopCapture()
 	}
 	mappedBuffers_.clear();
 
+	requests_.clear();
+
 	delete allocator_;
 
 	isCapturing_ = false;
@@ -701,7 +701,7 @@ void MainWindow::requestComplete(Request *request)
 	 */
 	{
 		QMutexLocker locker(&mutex_);
-		doneQueue_.enqueue({ request->buffers(), request->metadata() });
+		doneQueue_.enqueue(request);
 	}
 
 	QCoreApplication::postEvent(this, new CaptureEvent);
@@ -714,8 +714,7 @@ void MainWindow::processCapture()
 	 * if stopCapture() has been called while a CaptureEvent was posted but
 	 * not processed yet. Return immediately in that case.
 	 */
-	CaptureRequest request;
-
+	Request *request;
 	{
 		QMutexLocker locker(&mutex_);
 		if (doneQueue_.isEmpty())
@@ -725,11 +724,15 @@ void MainWindow::processCapture()
 	}
 
 	/* Process buffers. */
-	if (request.buffers_.count(vfStream_))
-		processViewfinder(request.buffers_[vfStream_]);
+	if (request->buffers().count(vfStream_))
+		processViewfinder(request->buffers().at(vfStream_));
 
-	if (request.buffers_.count(rawStream_))
-		processRaw(request.buffers_[rawStream_], request.metadata_);
+	if (request->buffers().count(rawStream_))
+		processRaw(request->buffers().at(rawStream_), request->metadata());
+
+	request->reuse();
+	QMutexLocker locker(&mutex_);
+	freeQueue_.enqueue(request);
 }
 
 void MainWindow::processViewfinder(FrameBuffer *buffer)
@@ -754,10 +757,13 @@ void MainWindow::processViewfinder(FrameBuffer *buffer)
 
 void MainWindow::queueRequest(FrameBuffer *buffer)
 {
-	Request *request = camera_->createRequest();
-	if (!request) {
-		qWarning() << "Can't create request";
-		return;
+	Request *request;
+	{
+		QMutexLocker locker(&mutex_);
+		if (freeQueue_.isEmpty())
+			return;
+
+		request = freeQueue_.dequeue();
 	}
 
 	request->addBuffer(vfStream_, buffer);
diff --git a/src/qcam/main_window.h b/src/qcam/main_window.h
index 5c61a4df..64bcfebc 100644
--- a/src/qcam/main_window.h
+++ b/src/qcam/main_window.h
@@ -8,6 +8,7 @@
 #define __QCAM_MAIN_WINDOW_H__
 
 #include <memory>
+#include <vector>
 
 #include <QElapsedTimer>
 #include <QIcon>
@@ -22,6 +23,7 @@
 #include <libcamera/camera_manager.h>
 #include <libcamera/controls.h>
 #include <libcamera/framebuffer_allocator.h>
+#include <libcamera/request.h>
 #include <libcamera/stream.h>
 
 #include "../cam/stream_options.h"
@@ -41,23 +43,6 @@ enum {
 	OptStream = 's',
 };
 
-class CaptureRequest
-{
-public:
-	CaptureRequest()
-	{
-	}
-
-	CaptureRequest(const Request::BufferMap &buffers,
-		       const ControlList &metadata)
-		: buffers_(buffers), metadata_(metadata)
-	{
-	}
-
-	Request::BufferMap buffers_;
-	ControlList metadata_;
-};
-
 class MainWindow : public QMainWindow
 {
 	Q_OBJECT
@@ -128,13 +113,16 @@ private:
 	Stream *vfStream_;
 	Stream *rawStream_;
 	std::map<const Stream *, QQueue<FrameBuffer *>> freeBuffers_;
-	QQueue<CaptureRequest> doneQueue_;
-	QMutex mutex_; /* Protects freeBuffers_ and doneQueue_ */
+	QQueue<Request *> doneQueue_;
+	QQueue<Request *> freeQueue_;
+	QMutex mutex_; /* Protects freeBuffers_, doneQueue_, and freeQueue_ */
 
 	uint64_t lastBufferTime_;
 	QElapsedTimer frameRateInterval_;
 	uint32_t previousFrames_;
 	uint32_t framesCaptured_;
+
+	std::vector<std::unique_ptr<Request>> requests_;
 };
 
 #endif /* __QCAM_MAIN_WINDOW__ */