libcamera: request: Make Stream pointer const

The Stream pointer just acts as a key in the Request object. There is no
good use-case to modify a stream from a pointer retrieved from the
Request, make it const. This allows pipeline handlers to better express
that the Stream pointer is retrieved in a Request should just be treated
as a key.

Signed-off-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

include/libcamera/request.h

@@ -31,7 +31,7 @@ public:
 		RequestCancelled,
 	};
 
-	using BufferMap = std::map<Stream *, FrameBuffer *>;
+	using BufferMap = std::map<const Stream *, FrameBuffer *>;
 
 	Request(Camera *camera, uint64_t cookie = 0);
 	Request(const Request &) = delete;
@@ -41,8 +41,8 @@ public:
 	ControlList &controls() { return *controls_; }
 	ControlList &metadata() { return *metadata_; }
 	const BufferMap &buffers() const { return bufferMap_; }
-	int addBuffer(Stream *stream, FrameBuffer *buffer);
-	FrameBuffer *findBuffer(Stream *stream) const;
+	int addBuffer(const Stream *stream, FrameBuffer *buffer);
+	FrameBuffer *findBuffer(const Stream *stream) const;
 
 	uint64_t cookie() const { return cookie_; }
 	Status status() const { return status_; }

src/cam/capture.cpp

@@ -169,7 +169,7 @@ void Capture::requestComplete(Request *request)
 	info << "fps: " << std::fixed << std::setprecision(2) << fps;
 
 	for (auto it = buffers.begin(); it != buffers.end(); ++it) {
-		Stream *stream = it->first;
+		const Stream *stream = it->first;
 		FrameBuffer *buffer = it->second;
 		const std::string &name = streamName_[stream];
 
@@ -209,7 +209,7 @@ void Capture::requestComplete(Request *request)
 	}
 
 	for (auto it = buffers.begin(); it != buffers.end(); ++it) {
-		Stream *stream = it->first;
+		const Stream *stream = it->first;
 		FrameBuffer *buffer = it->second;
 
 		request->addBuffer(stream, buffer);

src/cam/capture.h

@@ -36,7 +36,7 @@ private:
 	std::shared_ptr<libcamera::Camera> camera_;
 	libcamera::CameraConfiguration *config_;
 
-	std::map<libcamera::Stream *, std::string> streamName_;
+	std::map<const libcamera::Stream *, std::string> streamName_;
 	BufferWriter *writer_;
 	std::chrono::steady_clock::time_point last_;
 

src/libcamera/camera.cpp

@@ -279,7 +279,7 @@ public:
 	std::shared_ptr<PipelineHandler> pipe_;
 	std::string id_;
 	std::set<Stream *> streams_;
-	std::set<Stream *> activeStreams_;
+	std::set<const Stream *> activeStreams_;
 
 private:
 	bool disconnected_;
@@ -889,7 +889,7 @@ int Camera::queueRequest(Request *request)
 	}
 
 	for (auto const &it : request->buffers()) {
-		Stream *stream = it.first;
+		const Stream *stream = it.first;
 
 		if (p_->activeStreams_.find(stream) == p_->activeStreams_.end()) {
 			LOG(Camera, Error) << "Invalid request";

src/libcamera/pipeline/ipu3/ipu3.cpp

@@ -663,7 +663,7 @@ int PipelineHandlerIPU3::queueRequestDevice(Camera *camera, Request *request)
 
 	/* Queue all buffers from the request aimed for the ImgU. */
 	for (auto it : request->buffers()) {
-		Stream *stream = static_cast<Stream *>(it.first);
+		const Stream *stream = it.first;
 		FrameBuffer *buffer = it.second;
 		int ret;
 

src/libcamera/request.cpp

@@ -127,7 +127,7 @@ Request::~Request()
  * \retval -EEXIST The request already contains a buffer for the stream
  * \retval -EINVAL The buffer does not reference a valid Stream
  */
-int Request::addBuffer(Stream *stream, FrameBuffer *buffer)
+int Request::addBuffer(const Stream *stream, FrameBuffer *buffer)
 {
 	if (!stream) {
 		LOG(Request, Error) << "Invalid stream reference";
@@ -162,9 +162,9 @@ int Request::addBuffer(Stream *stream, FrameBuffer *buffer)
  * \return The buffer associated with the stream, or nullptr if the stream is
  * not part of this request
  */
-FrameBuffer *Request::findBuffer(Stream *stream) const
+FrameBuffer *Request::findBuffer(const Stream *stream) const
 {
-	auto it = bufferMap_.find(stream);
+	const auto it = bufferMap_.find(stream);
 	if (it == bufferMap_.end())
 		return nullptr;
 

src/qcam/main_window.h

@@ -126,7 +126,7 @@ private:
 	bool captureRaw_;
 	Stream *vfStream_;
 	Stream *rawStream_;
-	std::map<Stream *, QQueue<FrameBuffer *>> freeBuffers_;
+	std::map<const Stream *, QQueue<FrameBuffer *>> freeBuffers_;
 	QQueue<CaptureRequest> doneQueue_;
 	QMutex mutex_; /* Protects freeBuffers_ and doneQueue_ */
 

test/camera/buffer_import.cpp

@@ -51,7 +51,7 @@ protected:
 		completeRequestsCount_++;
 
 		/* Create a new request. */
-		Stream *stream = buffers.begin()->first;
+		const Stream *stream = buffers.begin()->first;
 		FrameBuffer *buffer = buffers.begin()->second;
 
 		request = camera_->createRequest();

test/camera/capture.cpp

@@ -44,7 +44,7 @@ protected:
 		completeRequestsCount_++;
 
 		/* Create a new request. */
-		Stream *stream = buffers.begin()->first;
+		const Stream *stream = buffers.begin()->first;
 		FrameBuffer *buffer = buffers.begin()->second;
 
 		request = camera_->createRequest();