libcamera: request: Add metadata information

A new ControlList container is needed to hold metadata coming out of
the IPA. The list of supported controls in this list is expected to
grow, so for now do not add a validator for the list.

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

include/libcamera/request.h

@@ -37,6 +37,7 @@ public:
 	~Request();
 
 	ControlList &controls() { return *controls_; }
+	ControlList &metadata() { return *metadata_; }
 	const std::map<Stream *, Buffer *> &buffers() const { return bufferMap_; }
 	int addBuffer(std::unique_ptr<Buffer> buffer);
 	Buffer *findBuffer(Stream *stream) const;
@@ -58,6 +59,7 @@ private:
 	Camera *camera_;
 	CameraControlValidator *validator_;
 	ControlList *controls_;
+	ControlList *metadata_;
 	std::map<Stream *, Buffer *> bufferMap_;
 	std::unordered_set<Buffer *> pending_;
 

src/libcamera/request.cpp

@@ -65,6 +65,11 @@ Request::Request(Camera *camera, uint64_t cookie)
 	 */
 	validator_ = new CameraControlValidator(camera);
 	controls_ = new ControlList(validator_);
+
+	/**
+	 * \todo: Add a validator for metadata controls.
+	 */
+	metadata_ = new ControlList(nullptr);
 }
 
 Request::~Request()
@@ -74,6 +79,7 @@ Request::~Request()
 		delete buffer;
 	}
 
+	delete metadata_;
 	delete controls_;
 	delete validator_;
 }
@@ -161,6 +167,14 @@ Buffer *Request::findBuffer(Stream *stream) const
 	return it->second;
 }
 
+/**
+ * \fn Request::metadata()
+ * \brief Retrieve the request's metadata
+ * \todo Offer a read-only API towards applications while keeping a read/write
+ * API internally.
+ * \return The metadata associated with the request
+ */
+
 /**
  * \fn Request::cookie()
  * \brief Retrieve the cookie set when the request was created