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diff --git a/src/ipa/raspberrypi/controller/metadata.hpp b/src/ipa/raspberrypi/controller/metadata.hpp
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+++ b/src/ipa/raspberrypi/controller/metadata.hpp
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+/* SPDX-License-Identifier: BSD-2-Clause */
+/*
+ * Copyright (C) 2019, Raspberry Pi (Trading) Limited
+ *
+ * metadata.hpp - general metadata class
+ */
+#pragma once
+
+// A simple class for carrying arbitrary metadata, for example about an image.
+
+#include <string>
+#include <mutex>
+#include <map>
+#include <memory>
+
+#include <boost/any.hpp>
+
+namespace RPi {
+
+class Metadata
+{
+public:
+	template<typename T> void Set(std::string const &tag, T const &value)
+	{
+		std::lock_guard<std::mutex> lock(mutex_);
+		data_[tag] = value;
+	}
+	template<typename T> int Get(std::string const &tag, T &value) const
+	{
+		std::lock_guard<std::mutex> lock(mutex_);
+		auto it = data_.find(tag);
+		if (it == data_.end())
+			return -1;
+		value = boost::any_cast<T>(it->second);
+		return 0;
+	}
+	void Clear()
+	{
+		std::lock_guard<std::mutex> lock(mutex_);
+		data_.clear();
+	}
+	Metadata &operator=(Metadata const &other)
+	{
+		std::lock_guard<std::mutex> lock(mutex_);
+		std::lock_guard<std::mutex> other_lock(other.mutex_);
+		data_ = other.data_;
+		return *this;
+	}
+	template<typename T> T *GetLocked(std::string const &tag)
+	{
+		// This allows in-place access to the Metadata contents,
+		// for which you should be holding the lock.
+		auto it = data_.find(tag);
+		if (it == data_.end())
+			return nullptr;
+		return boost::any_cast<T>(&it->second);
+	}
+	template<typename T>
+	void SetLocked(std::string const &tag, T const &value)
+	{
+		// Use this only if you're holding the lock yourself.
+		data_[tag] = value;
+	}
+	// Note: use of (lowercase) lock and unlock means you can create scoped
+	// locks with the standard lock classes.
+	// e.g. std::lock_guard<PisP::Metadata> lock(metadata)
+	void lock() { mutex_.lock(); }
+	void unlock() { mutex_.unlock(); }
+
+private:
+	mutable std::mutex mutex_;
+	std::map<std::string, boost::any> data_;
+};
+
+typedef std::shared_ptr<Metadata> MetadataPtr;
+
+} // namespace RPi