add disk I/O read asserts and fix i2p issue if a tracker responds with i2p peers when i2p is not configured on the client

src/peer_connection.cpp

@@ -2291,10 +2291,9 @@ namespace libtorrent
 		{
 #ifndef TORRENT_DISABLE_LOGGING
 			peer_log(peer_log_alert::info, "INVALID_REQUEST", "peer is not interested "
-				" t: %d n: %d h: %d block_limit: %d"
+				" t: %d n: %d block_limit: %d"
 				, int(t->torrent_file().piece_size(r.piece))
 				, t->torrent_file().num_pieces()
-				, t->has_piece_passed(r.piece)
 				, t->block_size());
 			peer_log(peer_log_alert::info, "INTERESTED", "artificial incoming INTERESTED message");
 #endif
@@ -2421,6 +2420,10 @@ namespace libtorrent
 			if (m_requests.empty())
 				m_counters.inc_stats_counter(counters::num_peers_up_requests);
 
+			TORRENT_ASSERT(t->valid_metadata());
+			TORRENT_ASSERT(r.piece >= 0);
+			TORRENT_ASSERT(r.piece < t->torrent_file().num_pieces());
+
 			m_requests.push_back(r);
 
 			if (t->alerts().should_post<incoming_request_alert>())
@@ -5155,6 +5158,11 @@ namespace libtorrent
 
 				// the callback function may be called immediately, instead of being posted
 				if (!t->need_loaded()) return;
+
+				TORRENT_ASSERT(t->valid_metadata());
+				TORRENT_ASSERT(r.piece >= 0);
+				TORRENT_ASSERT(r.piece < t->torrent_file().num_pieces());
+
 				t->inc_refcount("async_read");
 				m_disk_thread.async_read(&t->storage(), r
 					, boost::bind(&peer_connection::on_disk_read_complete

src/session_impl.cpp

@@ -1275,8 +1275,10 @@ namespace aux {
 		req.ssl_ctx = &m_ssl_ctx;
 #endif
 #if TORRENT_USE_I2P
-		req.i2pconn = &m_i2p_conn;
-		req.kind |= tracker_request::i2p;
+		if (!m_settings.get_str(settings_pack::i2p_hostname).empty())
+		{
+			req.i2pconn = &m_i2p_conn;
+		}
 #endif
 
 		if (is_any(req.bind_ip)) req.bind_ip = m_listen_interface.address();

src/torrent.cpp

@@ -3195,6 +3195,13 @@ namespace libtorrent
 			req.auth = tracker_login();
 			req.key = tracker_key();
 
+#ifdef TORRENT_USE_OPENSSL
+			if (is_i2p())
+			{
+				req.kind |= tracker_request::i2p;
+			}
+#endif
+
 #ifndef TORRENT_DISABLE_LOGGING
 			debug_log("==> TRACKER REQUEST \"%s\" event: %s abort: %d"
 				, req.url.c_str()