ipa: raspberrypi: Add RPiController::Metadata::mergeCopy

Add a new member function to RPiController::Metadata that copies unique
key/value pairs from one object to the other. This is different from
std::map::merge that would remove the key/value pairs from the source object.

Signed-off-by: Naushir Patuck <[email protected]>
Reviewed-by: Kieran Bingham <[email protected]>
Reviewed-by: David Plowman <[email protected]>
Signed-off-by: Laurent Pinchart <[email protected]>

Author: naushir

src/ipa/raspberrypi/controller/metadata.h

@@ -80,6 +80,16 @@ class LIBCAMERA_TSA_CAPABILITY("mutex") Metadata
 		data_.merge(other.data_);
 	}
 
+	void mergeCopy(const Metadata &other)
+	{
+		std::scoped_lock lock(mutex_, other.mutex_);
+		/*
+		 * If the metadata key exists, ignore this item and copy only
+		 * unique key/value pairs.
+		 */
+		data_.insert(other.data_.begin(), other.data_.end());
+	}
+
 	template<typename T>
 	T *getLocked(std::string const &tag)
 	{