libcamera: buffer: Add an accessor to the BufferMemory

Buffer instances reference memory, which is modelled internally by a
BufferMemory instance. Store a pointer to the BufferMemory in the Buffer
class, and populate it when the buffer is queued to the camera through a
request. This is useful for applications to access the buffer memory in
the buffer or request completion handler.

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

3 files changed, 4 insertions, 6 deletions

diff --git a/src/cam/buffer_writer.cpp b/src/cam/buffer_writer.cpp
index b7f2ed4f..1c044b06 100644
--- a/src/cam/buffer_writer.cpp
+++ b/src/cam/buffer_writer.cpp
@@ -19,8 +19,7 @@ BufferWriter::BufferWriter(const std::string &pattern)
 {
 }
 
-int BufferWriter::write(libcamera::Buffer *buffer, libcamera::BufferMemory *mem,
-			const std::string &streamName)
+int BufferWriter::write(libcamera::Buffer *buffer, const std::string &streamName)
 {
 	std::string filename;
 	size_t pos;
@@ -41,6 +40,7 @@ int BufferWriter::write(libcamera::Buffer *buffer, libcamera::BufferMemory *mem,
 	if (fd == -1)
 		return -errno;
 
+	libcamera::BufferMemory *mem = buffer->mem();
 	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 9bea205f..7bf785d1 100644
--- a/src/cam/buffer_writer.h
+++ b/src/cam/buffer_writer.h
@@ -16,8 +16,7 @@ class BufferWriter
 public:
 	BufferWriter(const std::string &pattern = "frame-#.bin");
 
-	int write(libcamera::Buffer *buffer, libcamera::BufferMemory *mem,
-		  const std::string &streamName);
+	int write(libcamera::Buffer *buffer, const std::string &streamName);
 
 private:
 	std::string pattern_;
diff --git a/src/cam/capture.cpp b/src/cam/capture.cpp
index 5ffa4ae2..df9602de 100644
--- a/src/cam/capture.cpp
+++ b/src/cam/capture.cpp
@@ -154,7 +154,6 @@ 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->buffers()[buffer->index()];
 		const std::string &name = streamName_[stream];
 
 		info << " " << name
@@ -163,7 +162,7 @@ void Capture::requestComplete(Request *request, const std::map<Stream *, Buffer
 		     << " bytesused: " << buffer->bytesused();
 
 		if (writer_)
-			writer_->write(buffer, mem, name);
+			writer_->write(buffer, name);
 	}
 
 	std::cout << info.str() << std::endl;