fixed bug in metadata extensions combined with encryption

ChangeLog

@@ -33,6 +33,7 @@
 	  incoming connection
 	* added more detailed instrumentation of the disk I/O thread
 
+	* fixed bug in metadata extensions combined with encryption
 	* refactored socket reading code to not use async. operations unnecessarily
 	* some timer optimizations
 	* removed the reuse-address flag on the listen socket

include/libtorrent/bt_peer_connection.hpp

@@ -265,6 +265,7 @@ public:
 		// these functions encrypt the send buffer if m_rc4_encrypted
 		// is true, otherwise it passes the call to the
 		// peer_connection functions of the same names
+		virtual void append_const_send_buffer(char const* buffer, int size);
 		void send_buffer(char const* buf, int size, int flags = 0);
 		buffer::interval allocate_send_buffer(int size);
 		template <class Destructor>

include/libtorrent/peer_connection.hpp

@@ -518,6 +518,8 @@ namespace libtorrent
 			m_send_buffer.append_buffer(buffer, size, size, destructor);
 		}
 
+		virtual void append_const_send_buffer(char const* buffer, int size);
+
 #ifndef TORRENT_DISABLE_RESOLVE_COUNTRIES	
 		void set_country(char const* c)
 		{

src/bt_peer_connection.cpp

@@ -657,14 +657,30 @@ namespace libtorrent
 #endif
 	}
 
+	void bt_peer_connection::append_const_send_buffer(char const* buffer, int size)
+	{
+		// if we're encrypting this buffer, we need to make a copy
+		// since we'll mutate it
+#ifndef TORRENT_DISABLE_ENCRYPTION
+		if (m_encrypted && m_rc4_encrypted)
+		{
+			send_buffer(buffer, size);
+		}
+		else
+#endif
+		{
+			append_const_send_buffer(buffer, size);
+		}
+	}
+
 	void bt_peer_connection::send_buffer(char const* buf, int size, int flags)
 	{
 		TORRENT_ASSERT(buf);
 		TORRENT_ASSERT(size > 0);
 		
+#ifndef TORRENT_DISABLE_ENCRYPTION
 		encrypt_pending_buffer();
 
-#ifndef TORRENT_DISABLE_ENCRYPTION
 		if (m_encrypted && m_rc4_encrypted)
 		{
 			TORRENT_ASSERT(send_buffer_size() == m_encrypted_bytes);

src/peer_connection.cpp

@@ -4535,6 +4535,17 @@ namespace libtorrent
 		m_packet_size = packet_size;
 	}
 
+	void nop(char*) {}
+
+	void peer_connection::append_const_send_buffer(char const* buffer, int size)
+	{
+		m_send_buffer.append_buffer((char*)buffer, size, size, &nop);
+#ifdef TORRENT_STATS
+		m_ses.m_buffer_usage_logger << log_time() << " append_const_send_buffer: " << size << std::endl;
+		m_ses.log_buffer_usage();
+#endif
+	}
+
 	void peer_connection::send_buffer(char const* buf, int size, int flags)
 	{
 		if (flags == message_type_request)

src/ut_metadata.cpp

@@ -66,8 +66,6 @@ namespace libtorrent { namespace
 		return (numerator + denominator - 1) / denominator;
 	}
 
-	void nop(char*) {}
-
 	struct ut_metadata_plugin : torrent_plugin
 	{
 		ut_metadata_plugin(torrent& t)
@@ -283,8 +281,8 @@ namespace libtorrent { namespace
 			io::write_uint8(m_message_index, header);
 
 			m_pc.send_buffer(msg, len + 6);
-			if (metadata_piece_size) m_pc.append_send_buffer(
-				(char*)metadata, metadata_piece_size, &nop);
+			if (metadata_piece_size) m_pc.append_const_send_buffer(
+				metadata, metadata_piece_size);
 		}
 
 		virtual bool on_extended(int length