pass the dht item object by const reference instead of by value

include/libtorrent/kademlia/item.hpp

@@ -74,7 +74,7 @@ TORRENT_EXPORT signature sign_mutable_item(
 class TORRENT_EXTRA_EXPORT item
 {
 public:
-	item() : m_seq(0), m_mutable(false)  {}
+	item() {}
 	item(public_key const& pk, span<char const> salt);
 	explicit item(entry v);
 	item(entry v
@@ -117,8 +117,8 @@ private:
 	std::string m_salt;
 	public_key m_pk;
 	signature m_sig;
-	sequence_number m_seq;
-	bool m_mutable;
+	sequence_number m_seq{0};
+	bool m_mutable = false;
 };
 
 } } // namespace libtorrent::dht

include/libtorrent/kademlia/put_data.hpp

@@ -54,7 +54,8 @@ struct put_data: traversal_algorithm
 	char const* name() const override;
 	void start() override;
 
-	void set_data(item const& data) { m_data = data; }
+	void set_data(item&& data) { m_data = std::move(data); }
+	void set_data(item const& data) = delete;
 
 	void set_targets(std::vector<std::pair<node_entry, std::string>> const& targets);
 

src/kademlia/node.cpp

@@ -516,15 +516,16 @@ void put(std::vector<std::pair<node_entry, std::string>> const& nodes
 	ta->start();
 }
 
-void put_data_cb(item i, bool auth
+void put_data_cb(item const& i, bool auth
 	, std::shared_ptr<put_data> const& ta
 	, std::function<void(item&)> const& f)
 {
 	// call data_callback only when we got authoritative data.
 	if (auth)
 	{
-		f(i);
-		ta->set_data(i);
+		item copy(i);
+		f(copy);
+		ta->set_data(std::move(copy));
 	}
 }
 
@@ -543,7 +544,7 @@ void node::put_item(sha1_hash const& target, entry const& data, std::function<vo
 	item i;
 	i.assign(data);
 	auto put_ta = std::make_shared<dht::put_data>(*this, std::bind(f, _2));
-	put_ta->set_data(i);
+	put_ta->set_data(std::move(i));
 
 	auto ta = std::make_shared<dht::get_item>(*this, target
 		, get_item::data_callback(), std::bind(&put, _1, put_ta));