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>

1 files changed, 2 insertions, 2 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();