refactor to use move with dht_state (#1163)

refactor to use move with dht_state

include/libtorrent/aux_/session_impl.hpp

@@ -331,11 +331,10 @@ namespace libtorrent
 			void add_dht_router(std::pair<std::string, int> const& node);
 			void set_dht_settings(dht_settings const& s);
 			dht_settings const& get_dht_settings() const { return m_dht_settings; }
-			void set_dht_state(dht::dht_state const& state);
+			void set_dht_state(dht::dht_state state);
 			void set_dht_storage(dht::dht_storage_constructor_type sc);
 			void start_dht();
 			void stop_dht();
-			void start_dht(dht::dht_state const& startup_state);
 			bool has_dht() const override;
 
 			// this is called for torrents when they are started

include/libtorrent/kademlia/dht_state.hpp

@@ -57,8 +57,6 @@ namespace dht
 	// .. _BEP32: http://bittorrent.org/beps/bep_0032.html
 	struct TORRENT_EXPORT dht_state
 	{
-		dht_state() = default;
-
 		// the id of the IPv4 node
 		node_id nid;
 		// the id of the IPv6 node
@@ -68,6 +66,8 @@ namespace dht
 		std::vector<udp::endpoint> nodes;
 		// the bootstrap nodes saved from the IPv6 buckets node
 		std::vector<udp::endpoint> nodes6;
+
+		void clear();
 	};
 
 	TORRENT_EXTRA_EXPORT dht_state read_dht_state(bdecode_node const& e);

include/libtorrent/kademlia/dht_tracker.hpp

@@ -68,11 +68,10 @@ namespace libtorrent { namespace dht
 			, dht_settings const& settings
 			, counters& cnt
 			, dht_storage_interface& storage
-			, dht_state const& state);
+			, dht_state state);
 		virtual ~dht_tracker();
 
-		void start(dht_state const& bootstrap
-			, find_data::nodes_callback const& f);
+		void start(find_data::nodes_callback const& f);
 		void stop();
 
 		// tell the node to recalculate its node id based on the current
@@ -147,6 +146,7 @@ namespace libtorrent { namespace dht
 
 		counters& m_counters;
 		dht_storage_interface& m_storage;
+		dht_state m_state; // to be used only once
 		node m_dht;
 #if TORRENT_USE_IPV6
 		node m_dht6;

src/kademlia/dht_state.cpp

@@ -63,6 +63,17 @@ namespace
 	}
 } // anonymous namespace
 
+	void dht_state::clear()
+	{
+		nid.clear();
+		nid6.clear();
+
+		nodes.clear();
+		nodes.shrink_to_fit();
+		nodes6.clear();
+		nodes6.shrink_to_fit();
+	}
+
 	dht_state read_dht_state(bdecode_node const& e)
 	{
 		dht_state ret;

src/kademlia/dht_tracker.cpp

@@ -79,13 +79,14 @@ namespace libtorrent { namespace dht
 		, dht_settings const& settings
 		, counters& cnt
 		, dht_storage_interface& storage
-		, dht_state const& state)
+		, dht_state state)
 		: m_counters(cnt)
 		, m_storage(storage)
-		, m_dht(udp::v4(), this, settings, state.nid
+		, m_state(std::move(state))
+		, m_dht(udp::v4(), this, settings, m_state.nid
 			, observer, cnt, m_nodes, storage)
 #if TORRENT_USE_IPV6
-		, m_dht6(udp::v6(), this, settings, state.nid6
+		, m_dht6(udp::v6(), this, settings, m_state.nid6
 			, observer, cnt, m_nodes, storage)
 #endif
 		, m_send_fun(send_fun)
@@ -136,8 +137,7 @@ namespace libtorrent { namespace dht
 		update_storage_node_ids();
 	}
 
-	void dht_tracker::start(dht_state const& bootstrap
-		, find_data::nodes_callback const& f)
+	void dht_tracker::start(find_data::nodes_callback const& f)
 	{
 		error_code ec;
 		refresh_key(ec);
@@ -154,10 +154,12 @@ namespace libtorrent { namespace dht
 
 		m_refresh_timer.expires_from_now(seconds(5), ec);
 		m_refresh_timer.async_wait(std::bind(&dht_tracker::refresh_timeout, self(), _1));
-		m_dht.bootstrap(bootstrap.nodes, f);
+
+		m_dht.bootstrap(m_state.nodes, f);
 #if TORRENT_USE_IPV6
-		m_dht6.bootstrap(bootstrap.nodes6, f);
+		m_dht6.bootstrap(m_state.nodes6, f);
 #endif
+		m_state.clear();
 	}
 
 	void dht_tracker::stop()
@@ -440,7 +442,6 @@ namespace libtorrent { namespace dht
 		else
 #endif
 			m_dht.direct_request(ep, e, f);
-
 	}
 
 	void dht_tracker::incoming_error(error_code const& ec, udp::endpoint const& ep)

src/session_impl.cpp

@@ -80,6 +80,7 @@ const rlim_t rlim_infinity = RLIM_INFINITY;
 #ifndef TORRENT_DISABLE_DHT
 #include "libtorrent/kademlia/dht_tracker.hpp"
 #include "libtorrent/kademlia/types.hpp"
+#include "libtorrent/kademlia/node_entry.hpp"
 #endif
 #include "libtorrent/enum_net.hpp"
 #include "libtorrent/config.hpp"
@@ -5601,18 +5602,6 @@ namespace aux {
 #ifndef TORRENT_DISABLE_DHT
 
 	void session_impl::start_dht()
-	{ start_dht(m_dht_state); }
-
-	namespace {
-
-		void on_bootstrap(alert_manager& alerts)
-		{
-			if (alerts.should_post<dht_bootstrap_alert>())
-				alerts.emplace_alert<dht_bootstrap_alert>();
-		}
-	}
-
-	void session_impl::start_dht(dht::dht_state const& startup_state)
 	{
 		INVARIANT_CHECK;
 
@@ -5629,7 +5618,7 @@ namespace aux {
 			, m_dht_settings
 			, m_stats_counters
 			, *m_dht_storage
-			, startup_state);
+			, std::move(m_dht_state));
 
 		for (auto const& n : m_dht_router_nodes)
 		{
@@ -5641,8 +5630,15 @@ namespace aux {
 			m_dht->add_node(n);
 		}
 		m_dht_nodes.clear();
+		m_dht_nodes.shrink_to_fit();
 
-		m_dht->start(startup_state, std::bind(&on_bootstrap, std::ref(m_alerts)));
+		auto cb = [this](
+			std::vector<std::pair<dht::node_entry, std::string>> const&)
+		{
+			if (m_alerts.should_post<dht_bootstrap_alert>())
+				m_alerts.emplace_alert<dht_bootstrap_alert>();
+		};
+		m_dht->start(cb);
 	}
 
 	void session_impl::stop_dht()
@@ -5661,9 +5657,9 @@ namespace aux {
 		m_dht_settings = settings;
 	}
 
-	void session_impl::set_dht_state(dht::dht_state const& state)
+	void session_impl::set_dht_state(dht::dht_state state)
 	{
-		m_dht_state = state;
+		m_dht_state = std::move(state);
 	}
 
 	void session_impl::set_dht_storage(dht::dht_storage_constructor_type sc)
@@ -5687,7 +5683,8 @@ namespace aux {
 		error_code ec;
 		if (tmp.empty() || bdecode(&tmp[0], &tmp[0] + tmp.size(), e, ec) != 0)
 			return;
-		start_dht(dht::read_dht_state(e));
+		m_dht_state = dht::read_dht_state(e);
+		start_dht();
 	}
 #endif