diff --git a/include/libtorrent/add_torrent_params.hpp b/include/libtorrent/add_torrent_params.hpp
index 9de2d1e0e..27cd0467b 100644
--- a/include/libtorrent/add_torrent_params.hpp
+++ b/include/libtorrent/add_torrent_params.hpp
@@ -39,14 +39,13 @@ POSSIBILITY OF SUCH DAMAGE.
 
 #include "libtorrent/storage_defs.hpp"
 #include "libtorrent/peer_id.hpp" // sha1_hash
-#include "libtorrent/torrent_handle.hpp"
 #include "libtorrent/version.hpp"
 
 namespace libtorrent
 {
 	class torrent_info;
-	class torrent;
 	struct torrent_plugin;
+	struct torrent_handle;
 
 	// The add_torrent_params is a parameter pack for adding torrents to a
 	// session. The key fields when adding a torrent are:
@@ -332,7 +331,7 @@ namespace libtorrent
 		// to avoid race conditions. For instance it may be important to have the
 		// plugin catch events that happen very early on after the torrent is
 		// created.
-		std::vector<boost::function<boost::shared_ptr<torrent_plugin>(torrent_handle, void*)> >
+		std::vector<boost::function<boost::shared_ptr<torrent_plugin>(torrent_handle const&, void*)> >
 			extensions;
 
 		// the default tracker id to be used when announcing to trackers. By
diff --git a/include/libtorrent/aux_/session_impl.hpp b/include/libtorrent/aux_/session_impl.hpp
index 5b5661970..a55e6208c 100644
--- a/include/libtorrent/aux_/session_impl.hpp
+++ b/include/libtorrent/aux_/session_impl.hpp
@@ -62,7 +62,6 @@ POSSIBILITY OF SUCH DAMAGE.
 
 #include "libtorrent/session.hpp" // for user_load_function_t
 #include "libtorrent/ip_voter.hpp"
-#include "libtorrent/torrent_handle.hpp"
 #include "libtorrent/entry.hpp"
 #include "libtorrent/socket.hpp"
 #include "libtorrent/peer_id.hpp"
@@ -111,6 +110,7 @@ namespace libtorrent
 	class torrent;
 	class alert;
 	struct cache_info;
+	struct torrent_handle;
 
 	namespace dht
 	{
@@ -193,7 +193,7 @@ namespace libtorrent
 
 #ifndef TORRENT_DISABLE_EXTENSIONS
 			void add_extension(boost::function<boost::shared_ptr<torrent_plugin>(
-				torrent_handle, void*)> ext);
+				torrent_handle const&, void*)> ext);
 			void add_ses_extension(boost::shared_ptr<plugin> ext);
 #endif
 #if TORRENT_USE_ASSERTS
diff --git a/include/libtorrent/extensions.hpp b/include/libtorrent/extensions.hpp
index 2cf21efa3..275540241 100644
--- a/include/libtorrent/extensions.hpp
+++ b/include/libtorrent/extensions.hpp
@@ -96,7 +96,7 @@ POSSIBILITY OF SUCH DAMAGE.
 // 
 // The signature of the function is::
 // 
-// 	boost::shared_ptr<torrent_plugin> (*)(torrent_handle, void*);
+// 	boost::shared_ptr<torrent_plugin> (*)(torrent_handle const&, void*);
 // 
 // The second argument is the userdata passed to ``session::add_torrent()`` or
 // ``torrent_handle::add_extension()``.
@@ -177,7 +177,6 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "libtorrent/sha1_hash.hpp" // for sha1_hash
 #include "libtorrent/error_code.hpp"
 #include "libtorrent/session_handle.hpp"
-#include "libtorrent/torrent_handle.hpp"
 
 namespace libtorrent
 {
@@ -191,6 +190,7 @@ namespace libtorrent
 	struct torrent_plugin;
 	struct add_torrent_params;
 	struct peer_connection_handle;
+	struct torrent_handle;
 
 	// this is the base class for a session plugin. One primary feature
 	// is that it is notified of all torrents that are added to the session,
@@ -208,7 +208,7 @@ namespace libtorrent
 		// If the plugin returns a torrent_plugin instance, it will be added
 		// to the new torrent. Otherwise, return an empty shared_ptr to a
 		// torrent_plugin (the default).
-		virtual boost::shared_ptr<torrent_plugin> new_torrent(torrent_handle, void*)
+		virtual boost::shared_ptr<torrent_plugin> new_torrent(torrent_handle const&, void*)
 		{ return boost::shared_ptr<torrent_plugin>(); }
 
 		// called when plugin is added to a session
diff --git a/include/libtorrent/extensions/lt_trackers.hpp b/include/libtorrent/extensions/lt_trackers.hpp
index 39fbce9a3..963fff8d8 100644
--- a/include/libtorrent/extensions/lt_trackers.hpp
+++ b/include/libtorrent/extensions/lt_trackers.hpp
@@ -36,7 +36,6 @@ POSSIBILITY OF SUCH DAMAGE.
 #ifndef TORRENT_DISABLE_EXTENSIONS
 
 #include "libtorrent/config.hpp"
-#include "libtorrent/torrent_handle.hpp"
 
 #include "libtorrent/aux_/disable_warnings_push.hpp"
 
@@ -47,12 +46,12 @@ POSSIBILITY OF SUCH DAMAGE.
 namespace libtorrent
 {
 	struct torrent_plugin;
-	class torrent;
+	struct torrent_handle;
 
 	// constructor function for the trackers exchange extension. This can
 	// either be passed in the add_torrent_params::extensions field, or
 	// via torrent_handle::add_extension().
-	boost::shared_ptr<torrent_plugin> TORRENT_EXPORT create_lt_trackers_plugin(torrent_handle, void*);
+	boost::shared_ptr<torrent_plugin> TORRENT_EXPORT create_lt_trackers_plugin(torrent_handle const&, void*);
 }
 
 #endif // TORRENT_DISABLE_EXTENSIONS
diff --git a/include/libtorrent/extensions/metadata_transfer.hpp b/include/libtorrent/extensions/metadata_transfer.hpp
index bc45fcf28..72681b3ab 100644
--- a/include/libtorrent/extensions/metadata_transfer.hpp
+++ b/include/libtorrent/extensions/metadata_transfer.hpp
@@ -36,7 +36,6 @@ POSSIBILITY OF SUCH DAMAGE.
 #ifndef TORRENT_DISABLE_EXTENSIONS
 
 #include "libtorrent/config.hpp"
-#include "libtorrent/torrent_handle.hpp"
 
 #include "libtorrent/aux_/disable_warnings_push.hpp"
 
@@ -49,7 +48,7 @@ POSSIBILITY OF SUCH DAMAGE.
 namespace libtorrent
 {
 	struct torrent_plugin;
-	class torrent;
+	struct torrent_handle;
 
 #ifndef TORRENT_NO_DEPRECATE
 	// constructor function for the metadata transfer extension. This
@@ -59,7 +58,7 @@ namespace libtorrent
 	// via torrent_handle::add_extension().
 	TORRENT_DEPRECATED
 	TORRENT_EXPORT boost::shared_ptr<torrent_plugin>
-	create_metadata_plugin(torrent_handle, void*);
+	create_metadata_plugin(torrent_handle const&, void*);
 #endif
 }
 #endif
diff --git a/include/libtorrent/extensions/smart_ban.hpp b/include/libtorrent/extensions/smart_ban.hpp
index 4926acce8..a2a5e35c9 100644
--- a/include/libtorrent/extensions/smart_ban.hpp
+++ b/include/libtorrent/extensions/smart_ban.hpp
@@ -35,8 +35,6 @@ POSSIBILITY OF SUCH DAMAGE.
 
 #ifndef TORRENT_DISABLE_EXTENSIONS
 
-#include "libtorrent/torrent_handle.hpp"
-
 #include "libtorrent/aux_/disable_warnings_push.hpp"
 
 #include <boost/shared_ptr.hpp>
@@ -47,6 +45,7 @@ POSSIBILITY OF SUCH DAMAGE.
 namespace libtorrent
 {
 	struct torrent_plugin;
+	struct torrent_handle;
 
 	// constructor function for the smart ban extension. The extension keeps
 	// track of the data peers have sent us for failing pieces and once the
@@ -54,7 +53,7 @@ namespace libtorrent
 	// out to have sent corrupt data.
 	// This function can either be passed in the add_torrent_params::extensions
 	// field, or via torrent_handle::add_extension().
-	TORRENT_EXPORT boost::shared_ptr<torrent_plugin> create_smart_ban_plugin(torrent_handle, void*);
+	TORRENT_EXPORT boost::shared_ptr<torrent_plugin> create_smart_ban_plugin(torrent_handle const&, void*);
 }
 
 #endif // TORRENT_DISABLE_EXTENSIONS
diff --git a/include/libtorrent/extensions/ut_metadata.hpp b/include/libtorrent/extensions/ut_metadata.hpp
index 9cad086d3..7080ee76a 100644
--- a/include/libtorrent/extensions/ut_metadata.hpp
+++ b/include/libtorrent/extensions/ut_metadata.hpp
@@ -36,7 +36,6 @@ POSSIBILITY OF SUCH DAMAGE.
 #ifndef TORRENT_DISABLE_EXTENSIONS
 
 #include "libtorrent/config.hpp"
-#include "libtorrent/torrent_handle.hpp"
 
 #include "libtorrent/aux_/disable_warnings_push.hpp"
 
@@ -47,7 +46,7 @@ POSSIBILITY OF SUCH DAMAGE.
 namespace libtorrent
 {
 	struct torrent_plugin;
-	class torrent;
+	struct torrent_handle;
 
 	// constructor function for the ut_metadata extension. The ut_metadata
 	// extension allows peers to request the .torrent file (or more
@@ -58,7 +57,7 @@ namespace libtorrent
 	// 
 	// This can either be passed in the add_torrent_params::extensions field, or
 	// via torrent_handle::add_extension().
-	TORRENT_EXPORT boost::shared_ptr<torrent_plugin> create_ut_metadata_plugin(torrent_handle, void*);
+	TORRENT_EXPORT boost::shared_ptr<torrent_plugin> create_ut_metadata_plugin(torrent_handle const&, void*);
 }
 
 #endif // TORRENT_DISABLE_EXTENSIONS
diff --git a/include/libtorrent/extensions/ut_pex.hpp b/include/libtorrent/extensions/ut_pex.hpp
index ff15616e2..00da8c1f9 100644
--- a/include/libtorrent/extensions/ut_pex.hpp
+++ b/include/libtorrent/extensions/ut_pex.hpp
@@ -38,7 +38,6 @@ POSSIBILITY OF SUCH DAMAGE.
 #ifndef TORRENT_DISABLE_EXTENSIONS
 
 #include "libtorrent/socket.hpp" // for endpoint
-#include "libtorrent/torrent_handle.hpp"
 
 #include "libtorrent/aux_/disable_warnings_push.hpp"
 
@@ -50,6 +49,7 @@ namespace libtorrent
 {
 	struct torrent_plugin;
 	struct peer_plugin;
+	struct torrent_handle;
 
 	// constructor function for the ut_pex extension. The ut_pex
 	// extension allows peers to gossip about their connections, allowing
@@ -59,7 +59,7 @@ namespace libtorrent
 	// 
 	// This can either be passed in the add_torrent_params::extensions field, or
 	// via torrent_handle::add_extension().
-	TORRENT_EXPORT boost::shared_ptr<torrent_plugin> create_ut_pex_plugin(torrent_handle, void*);
+	TORRENT_EXPORT boost::shared_ptr<torrent_plugin> create_ut_pex_plugin(torrent_handle const&, void*);
 
 	bool was_introduced_by(peer_plugin const* pp, tcp::endpoint const& ep);
 }
diff --git a/include/libtorrent/session_handle.hpp b/include/libtorrent/session_handle.hpp
index dc08dfe29..e2bbd9376 100644
--- a/include/libtorrent/session_handle.hpp
+++ b/include/libtorrent/session_handle.hpp
@@ -482,7 +482,7 @@ namespace libtorrent
 		//
 		// .. _`libtorrent plugins`: libtorrent_plugins.html
 		void add_extension(boost::function<boost::shared_ptr<torrent_plugin>(
-			torrent_handle, void*)> ext);
+			torrent_handle const&, void*)> ext);
 		void add_extension(boost::shared_ptr<plugin> ext);
 
 #ifndef TORRENT_NO_DEPRECATE
diff --git a/include/libtorrent/torrent.hpp b/include/libtorrent/torrent.hpp
index 276f82fc2..dc4c1001e 100644
--- a/include/libtorrent/torrent.hpp
+++ b/include/libtorrent/torrent.hpp
@@ -301,7 +301,7 @@ namespace libtorrent
 #ifndef TORRENT_DISABLE_EXTENSIONS
 		void add_extension(boost::shared_ptr<torrent_plugin>);
 		void remove_extension(boost::shared_ptr<torrent_plugin>);
-		void add_extension(boost::function<boost::shared_ptr<torrent_plugin>(torrent_handle, void*)> const& ext
+		void add_extension(boost::function<boost::shared_ptr<torrent_plugin>(torrent_handle const&, void*)> const& ext
 			, void* userdata);
 		void notify_extension_add_peer(tcp::endpoint const& ip, int src, int flags);
 #endif
diff --git a/include/libtorrent/torrent_handle.hpp b/include/libtorrent/torrent_handle.hpp
index 02ae65b58..84d27df6a 100644
--- a/include/libtorrent/torrent_handle.hpp
+++ b/include/libtorrent/torrent_handle.hpp
@@ -501,7 +501,7 @@ namespace libtorrent
 		// pointer. The function is expected to return a shared pointer to
 		// a torrent_plugin instance.
 		void add_extension(
-			boost::function<boost::shared_ptr<torrent_plugin>(torrent_handle, void*)> const& ext
+			boost::function<boost::shared_ptr<torrent_plugin>(torrent_handle const&, void*)> const& ext
 			, void* userdata = 0);
 
 		// ``set_metadata`` expects the *info* section of metadata. i.e. The
diff --git a/src/lt_trackers.cpp b/src/lt_trackers.cpp
index 6f3647b21..c333173f3 100644
--- a/src/lt_trackers.cpp
+++ b/src/lt_trackers.cpp
@@ -55,6 +55,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "libtorrent/alert_types.hpp"
 #include "libtorrent/io.hpp"
 #include "libtorrent/parse_url.hpp"
+#include "libtorrent/torrent_handle.hpp"
 
 namespace libtorrent { namespace
 {
@@ -378,7 +379,7 @@ namespace libtorrent { namespace
 namespace libtorrent
 {
 
-	boost::shared_ptr<torrent_plugin> TORRENT_EXPORT create_lt_trackers_plugin(torrent_handle th, void*)
+	boost::shared_ptr<torrent_plugin> TORRENT_EXPORT create_lt_trackers_plugin(torrent_handle const& th, void*)
 	{
 		torrent* t = th.native_handle().get();
 		if (t->valid_metadata() && t->torrent_file().priv()) return boost::shared_ptr<torrent_plugin>();
diff --git a/src/metadata_transfer.cpp b/src/metadata_transfer.cpp
index f0a8c6e37..fd59ee273 100644
--- a/src/metadata_transfer.cpp
+++ b/src/metadata_transfer.cpp
@@ -51,6 +51,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "libtorrent/hasher.hpp"
 #include "libtorrent/bencode.hpp"
 #include "libtorrent/torrent.hpp"
+#include "libtorrent/torrent_handle.hpp"
 #include "libtorrent/extensions.hpp"
 #include "libtorrent/extensions/metadata_transfer.hpp"
 #include "libtorrent/alert_types.hpp"
@@ -591,7 +592,7 @@ namespace libtorrent { namespace
 namespace libtorrent
 {
 
-	boost::shared_ptr<torrent_plugin> create_metadata_plugin(torrent_handle th, void*)
+	boost::shared_ptr<torrent_plugin> create_metadata_plugin(torrent_handle const& th, void*)
 	{
 		torrent* t = th.native_handle().get();
 		// don't add this extension if the torrent is private
diff --git a/src/session_handle.cpp b/src/session_handle.cpp
index c259476d2..b06ff13a5 100644
--- a/src/session_handle.cpp
+++ b/src/session_handle.cpp
@@ -414,7 +414,7 @@ namespace libtorrent
 	}
 #endif // TORRENT_NO_DEPRECATE
 
-	void session_handle::add_extension(boost::function<boost::shared_ptr<torrent_plugin>(torrent_handle, void*)> ext)
+	void session_handle::add_extension(boost::function<boost::shared_ptr<torrent_plugin>(torrent_handle const&, void*)> ext)
 	{
 #ifndef TORRENT_DISABLE_EXTENSIONS
 		TORRENT_ASYNC_CALL1(add_extension, ext);
diff --git a/src/session_impl.cpp b/src/session_impl.cpp
index 07f1fbbf6..75cd01ca7 100644
--- a/src/session_impl.cpp
+++ b/src/session_impl.cpp
@@ -96,6 +96,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "libtorrent/magnet_uri.hpp"
 #include "libtorrent/aux_/session_settings.hpp"
 #include "libtorrent/torrent_peer.hpp"
+#include "libtorrent/torrent_handle.hpp"
 #include "libtorrent/choker.hpp"
 #include "libtorrent/error.hpp"
 
@@ -868,13 +869,13 @@ namespace aux {
 
 #ifndef TORRENT_DISABLE_EXTENSIONS
 
-	typedef boost::function<boost::shared_ptr<torrent_plugin>(torrent_handle, void*)> ext_function_t;
+	typedef boost::function<boost::shared_ptr<torrent_plugin>(torrent_handle const&, void*)> ext_function_t;
 
 	struct session_plugin_wrapper : plugin
 	{
 		session_plugin_wrapper(ext_function_t const& f) : m_f(f) {}
 
-		virtual boost::shared_ptr<torrent_plugin> new_torrent(torrent_handle t, void* user)
+		virtual boost::shared_ptr<torrent_plugin> new_torrent(torrent_handle const& t, void* user)
 		{ return m_f(t, user); }
 		ext_function_t m_f;
 	};
@@ -4634,7 +4635,7 @@ retry:
 
 #ifndef TORRENT_DISABLE_EXTENSIONS
 		typedef std::vector<boost::function<
-			boost::shared_ptr<torrent_plugin>(torrent_handle, void*)> >
+			boost::shared_ptr<torrent_plugin>(torrent_handle const&, void*)> >
 			torrent_plugins_t;
 
 		for (torrent_plugins_t::const_iterator i = params.extensions.begin()
diff --git a/src/smart_ban.cpp b/src/smart_ban.cpp
index d4e51011d..77356a96e 100644
--- a/src/smart_ban.cpp
+++ b/src/smart_ban.cpp
@@ -47,6 +47,7 @@ POSSIBILITY OF SUCH DAMAGE.
 
 #include "libtorrent/hasher.hpp"
 #include "libtorrent/torrent.hpp"
+#include "libtorrent/torrent_handle.hpp"
 #include "libtorrent/extensions.hpp"
 #include "libtorrent/extensions/smart_ban.hpp"
 #include "libtorrent/disk_io_thread.hpp"
@@ -389,7 +390,7 @@ namespace
 namespace libtorrent
 {
 
-	boost::shared_ptr<torrent_plugin> create_smart_ban_plugin(torrent_handle th, void*)
+	boost::shared_ptr<torrent_plugin> create_smart_ban_plugin(torrent_handle const& th, void*)
 	{
 		torrent* t = th.native_handle().get();
 		return boost::shared_ptr<torrent_plugin>(new smart_ban_plugin(*t));
diff --git a/src/torrent.cpp b/src/torrent.cpp
index d073e8802..49dce1564 100644
--- a/src/torrent.cpp
+++ b/src/torrent.cpp
@@ -1499,7 +1499,7 @@ namespace libtorrent
 		m_extensions.erase(i);
 	}
 
-	void torrent::add_extension(boost::function<boost::shared_ptr<torrent_plugin>(torrent_handle, void*)> const& ext
+	void torrent::add_extension(boost::function<boost::shared_ptr<torrent_plugin>(torrent_handle const&, void*)> const& ext
 		, void* userdata)
 	{
 		boost::shared_ptr<torrent_plugin> tp(ext(get_handle(), userdata));
diff --git a/src/torrent_handle.cpp b/src/torrent_handle.cpp
index 1a7c0d116..5e7ea29de 100644
--- a/src/torrent_handle.cpp
+++ b/src/torrent_handle.cpp
@@ -296,7 +296,7 @@ namespace libtorrent
 	}
 
 	void torrent_handle::add_extension(
-		boost::function<boost::shared_ptr<torrent_plugin>(torrent_handle, void*)> const& ext
+		boost::function<boost::shared_ptr<torrent_plugin>(torrent_handle const&, void*)> const& ext
 		, void* userdata)
 	{
 #ifndef TORRENT_DISABLE_EXTENSIONS
diff --git a/src/ut_metadata.cpp b/src/ut_metadata.cpp
index 37ee812a8..8adde205f 100644
--- a/src/ut_metadata.cpp
+++ b/src/ut_metadata.cpp
@@ -50,6 +50,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "libtorrent/hasher.hpp"
 #include "libtorrent/bencode.hpp"
 #include "libtorrent/torrent.hpp"
+#include "libtorrent/torrent_handle.hpp"
 #include "libtorrent/extensions.hpp"
 #include "libtorrent/extensions/ut_metadata.hpp"
 #include "libtorrent/alert_types.hpp"
@@ -656,7 +657,7 @@ namespace libtorrent { namespace
 namespace libtorrent
 {
 
-	boost::shared_ptr<torrent_plugin> create_ut_metadata_plugin(torrent_handle th, void*)
+	boost::shared_ptr<torrent_plugin> create_ut_metadata_plugin(torrent_handle const& th, void*)
 	{
 		torrent* t = th.native_handle().get();
 		// don't add this extension if the torrent is private
diff --git a/src/ut_pex.cpp b/src/ut_pex.cpp
index a148ac07d..16a6bd59b 100644
--- a/src/ut_pex.cpp
+++ b/src/ut_pex.cpp
@@ -36,6 +36,7 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "libtorrent/peer_connection_handle.hpp"
 #include "libtorrent/bencode.hpp"
 #include "libtorrent/torrent.hpp"
+#include "libtorrent/torrent_handle.hpp"
 #include "libtorrent/extensions.hpp"
 #include "libtorrent/broadcast_socket.hpp"
 #include "libtorrent/socket_io.hpp"
@@ -659,7 +660,7 @@ namespace libtorrent { namespace
 
 namespace libtorrent
 {
-	boost::shared_ptr<torrent_plugin> create_ut_pex_plugin(torrent_handle th, void*)
+	boost::shared_ptr<torrent_plugin> create_ut_pex_plugin(torrent_handle const& th, void*)
 	{
 		torrent* t = th.native_handle().get();
 		if (t->torrent_file().priv() || (t->torrent_file().is_i2p()
diff --git a/test/test_metadata_extension.cpp b/test/test_metadata_extension.cpp
index 6f5c0dc23..58c7a9e8b 100644
--- a/test/test_metadata_extension.cpp
+++ b/test/test_metadata_extension.cpp
@@ -69,7 +69,7 @@ enum flags_t
 };
 
 void test_transfer(int flags
-	, boost::shared_ptr<libtorrent::torrent_plugin> (*constructor)(libtorrent::torrent_handle, void*)
+	, boost::shared_ptr<libtorrent::torrent_plugin> (*constructor)(libtorrent::torrent_handle const&, void*)
 	, int timeout)
 {
 	using namespace libtorrent;