libcamera: buffer: Split memory information to BufferMemory

The Buffer class is a large beast the stores information about the
buffer memory, dynamic metadata related to the frame stored in the
buffer, and buffer reference data (in the index). In order to implement
buffer import we will need to extend this with dmabuf file descriptors,
making usage of the class even more complex.

Refactor the Buffer class by splitting the buffer memory information to
a BufferMemory class, and repurposing the Buffer class to reference a
buffer and to store dynamic metadata. The BufferMemory class becomes a
long term storage, valid and stable from the time buffer memory is
allocated to the time it is freed. The Buffer class, on the other hand,
becomes transient, is created on demand when an application requires a
buffer, is given to a request, and is deleted when the request
completes.

Buffer and BufferMemory don't need to be copied, so their copy
constructor and assignment operators are deleted.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>

3 files changed, 32 insertions, 12 deletions

diff --git a/src/cam/buffer_writer.cpp b/src/cam/buffer_writer.cpp
index e0374ffc..b7f2ed4f 100644
--- a/src/cam/buffer_writer.cpp
+++ b/src/cam/buffer_writer.cpp
@@ -19,7 +19,7 @@ BufferWriter::BufferWriter(const std::string &pattern)
 {
 }
 
-int BufferWriter::write(libcamera::Buffer *buffer,
+int BufferWriter::write(libcamera::Buffer *buffer, libcamera::BufferMemory *mem,
 			const std::string &streamName)
 {
 	std::string filename;
@@ -41,7 +41,7 @@ int BufferWriter::write(libcamera::Buffer *buffer,
 	if (fd == -1)
 		return -errno;
 
-	for (libcamera::Plane &plane : buffer->planes()) {
+	for (libcamera::Plane &plane : mem->planes()) {
 		void *data = plane.mem();
 		unsigned int length = plane.length();
 
diff --git a/src/cam/buffer_writer.h b/src/cam/buffer_writer.h
index 7bf785d1..9bea205f 100644
--- a/src/cam/buffer_writer.h
+++ b/src/cam/buffer_writer.h
@@ -16,7 +16,8 @@ class BufferWriter
 public:
 	BufferWriter(const std::string &pattern = "frame-#.bin");
 
-	int write(libcamera::Buffer *buffer, const std::string &streamName);
+	int write(libcamera::Buffer *buffer, libcamera::BufferMemory *mem,
+		  const std::string &streamName);
 
 private:
 	std::string pattern_;
diff --git a/src/cam/capture.cpp b/src/cam/capture.cpp
index 6b842d73..1cf59063 100644
--- a/src/cam/capture.cpp
+++ b/src/cam/capture.cpp
@@ -95,13 +95,14 @@ int Capture::capture(EventLoop *loop)
 		std::map<Stream *, Buffer *> map;
 		for (StreamConfiguration &cfg : *config_) {
 			Stream *stream = cfg.stream();
-			map[stream] = &stream->bufferPool().buffers()[i];
-		}
-
-		ret = request->setBuffers(map);
-		if (ret < 0) {
-			std::cerr << "Can't set buffers for request" << std::endl;
-			return ret;
+			std::unique_ptr<Buffer> buffer = stream->createBuffer(i);
+
+			ret = request->addBuffer(std::move(buffer));
+			if (ret < 0) {
+				std::cerr << "Can't set buffer for request"
+					  << std::endl;
+				return ret;
+			}
 		}
 
 		requests.push_back(request);
@@ -155,6 +156,7 @@ void Capture::requestComplete(Request *request, const std::map<Stream *, Buffer
 	for (auto it = buffers.begin(); it != buffers.end(); ++it) {
 		Stream *stream = it->first;
 		Buffer *buffer = it->second;
+		BufferMemory *mem = &stream->bufferPool().buffers()[buffer->index()];
 		const std::string &name = streamName_[stream];
 
 		info << " " << name
@@ -163,17 +165,34 @@ void Capture::requestComplete(Request *request, const std::map<Stream *, Buffer
 		     << " bytesused: " << buffer->bytesused();
 
 		if (writer_)
-			writer_->write(buffer, name);
+			writer_->write(buffer, mem, name);
 	}
 
 	std::cout << info.str() << std::endl;
 
+	/*
+	 * Create a new request and populate it with one buffer for each
+	 * stream.
+	 */
 	request = camera_->createRequest();
 	if (!request) {
 		std::cerr << "Can't create request" << std::endl;
 		return;
 	}
 
-	request->setBuffers(buffers);
+	for (auto it = buffers.begin(); it != buffers.end(); ++it) {
+		Stream *stream = it->first;
+		Buffer *buffer = it->second;
+		unsigned int index = buffer->index();
+
+		std::unique_ptr<Buffer> newBuffer = stream->createBuffer(index);
+		if (!newBuffer) {
+			std::cerr << "Can't create buffer " << index << std::endl;
+			return;
+		}
+
+		request->addBuffer(std::move(newBuffer));
+	}
+
 	camera_->queueRequest(request);
 }