2006-07-19 Tatsuhiro Tsujikawa <tujikawa at rednoah dot com>

	* src/SharedHandle.h: New class.

	To wrap Socket, Command, PeerMessage and Peer with SharedHandle:

	* src/HttpResponseCommand.h
	(HttpResponseCommand): Wrapped Socket.
	* src/SocketCore.h
	(operator==): New function.
	(operator!=): New function.
	(operator<): New function.
	(getSockfd): New function.
	(isOpen): New function.
	(writeData): New function.
	* src/SocketCore.cc
	(operator==): New function.
	(operator!=): New function.
	(operator<): New function.
	* src/AbstractCommand.h
	(socket): Changed its type to SocketHandle.
	(setReadCheckSocket): Replaced Socket with SocketHandle.
	(setWriteCheckSocket): Replaced Socket with SocketHandle.
	(disableReadCheckSocket): New function.
	(disableWriteCheckSocket): New function.
	(readCheckTarget): Changed its type to SocketHandle.
	(writeCheckTarget): Changed its type to SocketHandle.
	(AbstractCommand): Replaced Socket with SocketHandle.
	* src/AbstractCommand.cc
	(AbstractCommand): Replaced Socket with SocketHandle.
	(~AbstractCommand): Removed the deallocation for Socket object.
	(disableReadCheckSocket): New function.
	(setReadCheckSocket): Replaced Socket with SocketHandle.
	(disableWriteCheckSocket): New function.
	(setWriteCheckSocket): Replaced Socket with SocketHandle.
	* src/HttpDownloadCommand.cc
	(DownloadCommand): Replaced Socket with SocketHandle.
	* src/PeerAbstractCommand.h
	(socket): Changed its type to SocketHandle.
	(peer): Changed its type to PeerHandle.
	(setReadCheckSocket): Replaced Socket with SocketHandle.
	(setWriteCheckSocket): Replaced Socket with SocketHandle.
	(disableReadCheckSocket): New function.
	(disableWriteCheckSocket): New function.
	(readCheckTarget): Changed its type to SocketHandle.
	(writeCheckTarget): Changed its type to SocketHandle.
	(PeerAbstractCommand): Replaced Socket with SocketHandle.
	Replaced Peer with PeerHandle.
	* src/HttpRequestCommand.cc
	(HttpRequestCommand): Replaced Socket with SocketHandle.
	Use disableReadCheckSocket.
	* src/PeerInitiateConnectionCommand.h
	(PeerInitiateConnectionCommand): Replaced Peer with PeerHandle.
	* src/PeerChokeCommand.cc
	(UploadFaster::operator()): Replaced Peer with PeerHandle.
	(DownloadFaster::operator()): Replaced Peer with PeerHandle.
	(execute): Use PeerHandle.
	* src/PeerConnection.h
	(HandshakeMessage.h): Removed include of HandshakeMessage.h.
	(socket): Changed its type to SocketHandle.
	(PeerConnection): Replaced Socket with SocketHandle.	
	* src/PeerConnection.cc
	(PeerConnection): Replaced Socket with SocketHandle.
	* src/PeerInteractionCommand.h
	(PeerInteractionCommand): Replaced socket with SocketHandle.
	Replaced Peer with PeerHandle.	
	* src/PeerInteractionCommand.cc
	(PeerInteractionCommand): Replaced Socket with SocketHandle.
	Replaced Peer with PeerHandle.
	(executeInternal): Use disableWriteCheckSocket.
	Use HandshakeMessageHandle.
	(receiveMessages): Use PeerMessageHandle.
	(prepareForNextPeer): Use PeerHandle.
	* src/HttpProxyRequestCommand.h
	(HttpProxyRequestCommand): Replaced Socket with SocketHandle.
	* src/HttpResponseCommand.cc
	(HttpResponseCommand): Replaced Socket with SocketHandle.
	* src/TorrentMan.cc
	(nullPeer): Added external reference.
	(~TorrentMan): Removed the deallocation of the elements of 
peers.
	(addPeer): Rewritten.
	(isPeerAvailable): Use nullPeer.
	(deleteOldpeers): Replaced with deleteErrorPeer.
	(deleteErrorPeer): New function.
	(getPeer): Use PeerHandle and nullPeer.
	(hasMissingPiece): Replaced Peer with PeerHandle.
	(getMissingPieceIndex): Replaced Peer with PeerHandle.
	(getMissingFastPieceIndex): Replaced Peer with PeerHandle.
	(getMissingFastPiece): Replaced Peer with PeerHandle.
	(getMissingPiece): Replaced Peer with PeerHandle.
	* src/FtpNegotiateCommand.cc
	(FtpNegotiationCommand): Replaced Peer with PeerHandle.
	(~FtpNegotiationCommand): Removed the deallocation of Sockets.
	(recvGreeting): Use disableWriteCheckSocket.
	(recvPasv): Removed the allocation of Socket.
	Use disableReadCheckSocket.
	(sendRestPasv): Use disableWriteCheckSocket.
	(recvRetr): Changed assertion.
	* src/PeerInteraction.h
	(SharedHandle.h): Included SharedHandle.h.
	(PeerMessageHandle): New type definition.
	(HandshakeMessageHandle): New type definition.
	(MessageQueue): Changed. Now its element is of type 
PeerMessageHandle.
	(peer): Changed its type to PeerHandle.
	(createHandshakeMessage): Replaced HandshakeMessage with
	HandshakeMessageHandle.
	(createPeerMessage): Replaced PeerMessageHandle with 
PeerMessage.
	(PeerInteraction): Replaced Peer with PeerHandle.
	Replaced Socket with SocketHandle.
	(addMessage): Replaced PeerMessage with PeerMessageHandle.
	(receiveMessage): Replaced PeerMessage with PeerMessageHandle.
	(receiveHandshake): Replaced HandshakeMessage with
	HandshakeMessageHandle.
	* src/PeerInteraction.cc
	(PeerInteraction): Replaced Peer with PeerHandle.
	Replaced Socket with SocketHandle.
	(~PeerInteraction): Removed the deallocation of the elements of
	messageQueue.
	(MsgPushBack::operator()): Replaced PeerMessage with 
PeerMessageHandle.
	(isSendingMessageInProgress): Replaced PeerMessage with
	PeerMessageHandle.
	(sendMessages): Use PeerMessageHandle. Removed try-catch block.
	(addMessage): Replaced PeerMessage with PeerMessageHandle.
	(rejectAllPieceMessageInQueue): Use PeerMessageHandle.
	(rejectPieceMessageInQueue): Use PeerMessageHandle.
	(abortPiece): Use PeerMessageHandle.
	(receiveHandshake): Replaced HandshakeMessage with
	HandshakeMessageHandle. Removed try-catch block.
	(createHandshakeMessage): Replaced HandshakeMessage with
	HandshakeMessageHandle.
	(receiveMessage): Replaced PeerMessage with PeerMessageHandle.
	Removed try-catch block.
	(createPeerMessage): Replaced PeerMessage with 
PeerMessageHandle.
	* src/HttpProxyResponseCommand.cc
	(HttpProxyRequestCommand): Replaced Socket with SocketHandle.
	* src/FtpTunnelResponseCommand.h
	(FtpTunnelResponseCommand): Replaced Socket with SocketHandle.
	* src/HttpConnection.cc
	(HttpConnection): Replaced Socket with SocketHandle.
	* src/PeerAbstractCommand.cc
	(PeerAbstractCommand): Replaced Socket with SocketHandle.
	(~PeerAbstractCommand): Removed the deallocation of socket.
	Use disableReadCheckSocket, disableWriteCheckSocket.
	(disableReadCheckSocket): New function.
	(setReadCheckSocket): Replaced Socket with SocketHandle.
	(disableWriteCheckSocket): New function.
	(setWriteCheckSocket): Replaced Socket with SocketHandle.
	* src/InitiateConnectionCommandFactory.h: Corrected indentation.
	* src/FtpTunnelRequestCommand.cc
	(FtpTunnelRequestCommand): Replaced Socket with SocketHandle.
	(~FtpTunnelRequestCommand): Corrected indentation.
	* src/DownloadCommand.h
	(DownloadCommand): Replaced Socket with SocketHandle.
	* src/PeerListenCommand.cc
	(PeerListenCommand): Removed the initialization of socket.
	(~PeerListenCommand): Removed the deallocation of socket.
	(bindPort): Use SocketHandle.
	(execute): Use SocketHandle and PeerHandle.
	* src/FtpDowndloadCommand.cc
	(FtpDownloadCommand): Replaced Socket with SocketHandle.
	(~FtpDownloadCommand): Removed the deallocation of ctrlSocket.
	* src/main.cc
	(main): Corrected indentation.
	* src/HttpInitiateConnectionCommand.cc
	(HttpInitiateConnectionCommand): Replaced Socket with 
SocketHandle.
	(executeInternal): Removed the allocation of socket.
	* src/HttpRequestCommand.h
	(HttpRequestCommand): Replaced Socket with SocketHandle.
	* src/FtpNegotiationCommand.h
	(dataSocket): Changed its type to SocketHandle.
	(serverSocket): Changed its type to SocketHandle.
	(FtpNegotiationCommand): Replaced Socket with SocketHandle.
	* src/TorrentMan.h
	(MAX_PEER_UPDATE): Removed.
	(MAX_PEERS): New definition.
	(Peers): The element is now of type PeerHandle.
	(addPeer): Replaced Peer with PeerHandle. Removed 'duplicate' 
argument.
	(getPeer): Replaced Peer with PeerHandle.
	(deleteOldErrorPeers): Removed.
	(deleteErrorPeer): New function.
	(hasMissingPiece): Replaced Peer with PeerHandle.
	(getMissingPieceIndex): Replaced Peer with PeerHandle.
	(getMissingPiece): Replaced Peer with PeerHandle.
	(getMissingFastPieceIndex): Replaced Peer with PeerHandle.
	(getMissingFastPiece): Replaced Peer with PeerHandle.
	(addActivePeer): Replaced Peer with PeerHandle.
	(deleteActivePeer): Replaced Peer with PeerHandle.
	Added a check for the return value of find.
	* src/FtpTunnelResponseCommand.cc
	(FtpTunnelResponseCommand): Replaced Socket with SocketHandle.
	* src/FtpInitiateConnectionCommand.cc
	(executeInternal): Removed the allocation of socket.
	* src/DownloadEngine.h
	(Sockets): An element is now of type SocketHandle.
	(SockCmdMap): A key is of type SocketHandle, a value is of type 
int.
	(CommandUuids): New type definition.
	(rsockets): Changed its type to SockCmdMap.
	(wsockets): Changed its type to SockCmdMap.
	(addSocket): Rewritten.
	(deleteSocket): Rewritten.
	(addSocketForReadCheck): Rewritten.
	(deleteSocketForReadCheck): Rewritten.
	(addSocketForWriteCheck): Rewritten.
	(deleteSocketForWriteCheck): Rewritten.
	(PairFind): New template class.
	* src/HttpDownloadCommand.h
	(HttpDownloadCommand): Replaced Socket with SocketHandle.
	* src/FtpConnection.cc
	(FtpConnection): Replaced Socket with SocketHandle.
	(sendPort): Removed the allocation of serverSocket. Removed 
try-catch
	block.
	* src/InitiateConnectionCommandFactory.cc
	(DlAbortEx.h): Included DlAbortEx.h.
	(createInitiateConnectionCommand): Throw exception if the 
protocol of
	requested URI is not supported.
	* src/Peer.cc
	(nullPeer): Changed its type to PeerHandle.
	(operator==): New function.
	(operator!=): New function.
	* src/Peer.h
	(SharedHandle.h): Included SharedHandle.h.
	(operator==): New function.
	(operator!=): New function.
	(Peer): Added the default constructor.
	Use resetStatus() to initialize member variables.
	(nullPeer): Removed.
	* src/TrackerUpdateCommand.cc
	(execute): Brushed up using SharedHandle. Replaced 
MAX_PEER_UPDATE
	with MIN_PEERS.
	* src/PeerListenCommand.h
	(socket): Changed its type to SocketHandle.
	* src/Command.h
	(CommandUuid): New type definition.
	(uuid): New variable.
	(uuidGen): New variable.
	(Command): Added the initialization of uuid.
	(getUuid): New function.
	* src/Socket.h
	(Socket): Removed.
	(SocketHandle): New type definition.
	* src/DownloadEngine.h
	(FindCommand): New function object.
	(run): The portion of socket check was rewritten.
	(SetDescriptor): New function object.
	(AccumulateActiveCommandUuid): New function object.
	(waitData): Rewritten.
	(addSocket): Rewritten.
	(deleteSocket): Rewritten.
	(addSocketForReadCheck): Rewritten.
	(addSocketForWriteCheck): Rewritten.
	(deleteSocketForReadCheck): Rewritten.
	(deleteSocketForWriteCheck): Rewritten.
	* src/HttpProxyResponseCommand.h
	(HttpProxyResponseCommand): Replaced Socket with SocketHandle.
	* src/HttpConnection.h
	(socket): Changed its type to SocketHandle.
	(HttpConnection): Replaced Socket with SocketHandle.
	* src/PeerInitiateConnectionCommand.cc
	(PeerInitiateConnectionCommand): Replaced Peer with PeerHandle.
	(executeInternal): Removed the allocation of socket.
	(prepareForNextPeer): Use PeerHandle.
	* src/PeerMessage.h
	(peer): Changed its type to PeerHandle.
	(getPeer): Replaced Peer with PeerHandle.
	(setPeer): Replaced Peer with PeerHandle.
	* src/DownloadCommand.cc
	(DownloadCommand): Replaced Socket with SocketHandle.
	* src/FtpConnection.h
	(socket): Changed its type to SocketHandle.
	(FtpConnection): Replaced Socket with SocketHandle.
	(sendPort); Replaced Socket with SocketHandle.
	* src/FtpDowndloadCommand.h
	(ctrlSocket): Changed its type to SocketHandle.
	(FtpDownloadCommand): Replaced Socket with SocketHandle.
	* src/HttpProxyRequestCommand.cc
	(HttpProxyRequestCommand): Replaced Socket with SocketHandle.
	* src/FtpTunnelRequestCommand.h
	(FtpTunnelRequestCommand): Replaced Socket with SocketHandle.
	
	etc
	
	* src/PeerChokeCommand.h
	(setAllPeerChoked): Removed.
	(setAllPeerResetDelta): Removed.
	* src/PeerChokeCommand.cc
	(setAllPeerChoked): Removed.
	(ChokePeer): New function object.
	(setAllPeerResetDelta): Removed.
	(ResetDelta): New function object.
	(orderByDownloadRate): Fixed a bug: use DowloadFaster, not 
UploadFaster
	(execute): Show download speed when the local node is a seeder.
	setAllPeerChoked and setAllPeerResetDelta were rewritten
	using STL.
	* src/TrackerWatcherCommand.h
	(MIN_PEERS): Removed.
	* src/TorrentMan.cc
	(getPeer): Replaced MAX_PEER_UPDATE with MIN_PEERS.

62 files changed, 922 insertions, 626 deletions

diff --git a/ChangeLog b/ChangeLog
index 17bb3473..61d533d5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,301 @@
+2006-07-19  Tatsuhiro Tsujikawa  <tujikawa at rednoah dot com>
+
+	* src/SharedHandle.h: New class.
+
+	To wrap Socket, Command, PeerMessage and Peer with SharedHandle:
+
+	* src/HttpResponseCommand.h
+	(HttpResponseCommand): Wrapped Socket.
+	* src/SocketCore.h
+	(operator==): New function.
+	(operator!=): New function.
+	(operator<): New function.
+	(getSockfd): New function.
+	(isOpen): New function.
+	(writeData): New function.
+	* src/SocketCore.cc
+	(operator==): New function.
+	(operator!=): New function.
+	(operator<): New function.
+	* src/AbstractCommand.h
+	(socket): Changed its type to SocketHandle.
+	(setReadCheckSocket): Replaced Socket with SocketHandle.
+	(setWriteCheckSocket): Replaced Socket with SocketHandle.
+	(disableReadCheckSocket): New function.
+	(disableWriteCheckSocket): New function.
+	(readCheckTarget): Changed its type to SocketHandle.
+	(writeCheckTarget): Changed its type to SocketHandle.
+	(AbstractCommand): Replaced Socket with SocketHandle.
+	* src/AbstractCommand.cc
+	(AbstractCommand): Replaced Socket with SocketHandle.
+	(~AbstractCommand): Removed the deallocation for Socket object.
+	(disableReadCheckSocket): New function.
+	(setReadCheckSocket): Replaced Socket with SocketHandle.
+	(disableWriteCheckSocket): New function.
+	(setWriteCheckSocket): Replaced Socket with SocketHandle.
+	* src/HttpDownloadCommand.cc
+	(DownloadCommand): Replaced Socket with SocketHandle.
+	* src/PeerAbstractCommand.h
+	(socket): Changed its type to SocketHandle.
+	(peer): Changed its type to PeerHandle.
+	(setReadCheckSocket): Replaced Socket with SocketHandle.
+	(setWriteCheckSocket): Replaced Socket with SocketHandle.
+	(disableReadCheckSocket): New function.
+	(disableWriteCheckSocket): New function.
+	(readCheckTarget): Changed its type to SocketHandle.
+	(writeCheckTarget): Changed its type to SocketHandle.
+	(PeerAbstractCommand): Replaced Socket with SocketHandle.
+	Replaced Peer with PeerHandle.
+	* src/HttpRequestCommand.cc
+	(HttpRequestCommand): Replaced Socket with SocketHandle.
+	Use disableReadCheckSocket.
+	* src/PeerInitiateConnectionCommand.h
+	(PeerInitiateConnectionCommand): Replaced Peer with PeerHandle.
+	* src/PeerChokeCommand.cc
+	(UploadFaster::operator()): Replaced Peer with PeerHandle.
+	(DownloadFaster::operator()): Replaced Peer with PeerHandle.
+	(execute): Use PeerHandle.
+	* src/PeerConnection.h
+	(HandshakeMessage.h): Removed include of HandshakeMessage.h.
+	(socket): Changed its type to SocketHandle.
+	(PeerConnection): Replaced Socket with SocketHandle.	
+	* src/PeerConnection.cc
+	(PeerConnection): Replaced Socket with SocketHandle.
+	* src/PeerInteractionCommand.h
+	(PeerInteractionCommand): Replaced socket with SocketHandle.
+	Replaced Peer with PeerHandle.	
+	* src/PeerInteractionCommand.cc
+	(PeerInteractionCommand): Replaced Socket with SocketHandle.
+	Replaced Peer with PeerHandle.
+	(executeInternal): Use disableWriteCheckSocket.
+	Use HandshakeMessageHandle.
+	(receiveMessages): Use PeerMessageHandle.
+	(prepareForNextPeer): Use PeerHandle.
+	* src/HttpProxyRequestCommand.h
+	(HttpProxyRequestCommand): Replaced Socket with SocketHandle.
+	* src/HttpResponseCommand.cc
+	(HttpResponseCommand): Replaced Socket with SocketHandle.
+	* src/TorrentMan.cc
+	(nullPeer): Added external reference.
+	(~TorrentMan): Removed the deallocation of the elements of peers.
+	(addPeer): Rewritten.
+	(isPeerAvailable): Use nullPeer.
+	(deleteOldpeers): Replaced with deleteErrorPeer.
+	(deleteErrorPeer): New function.
+	(getPeer): Use PeerHandle and nullPeer.
+	(hasMissingPiece): Replaced Peer with PeerHandle.
+	(getMissingPieceIndex): Replaced Peer with PeerHandle.
+	(getMissingFastPieceIndex): Replaced Peer with PeerHandle.
+	(getMissingFastPiece): Replaced Peer with PeerHandle.
+	(getMissingPiece): Replaced Peer with PeerHandle.
+	* src/FtpNegotiateCommand.cc
+	(FtpNegotiationCommand): Replaced Peer with PeerHandle.
+	(~FtpNegotiationCommand): Removed the deallocation of Sockets.
+	(recvGreeting): Use disableWriteCheckSocket.
+	(recvPasv): Removed the allocation of Socket.
+	Use disableReadCheckSocket.
+	(sendRestPasv): Use disableWriteCheckSocket.
+	(recvRetr): Changed assertion.
+	* src/PeerInteraction.h
+	(SharedHandle.h): Included SharedHandle.h.
+	(PeerMessageHandle): New type definition.
+	(HandshakeMessageHandle): New type definition.
+	(MessageQueue): Changed. Now its element is of type PeerMessageHandle.
+	(peer): Changed its type to PeerHandle.
+	(createHandshakeMessage): Replaced HandshakeMessage with
+	HandshakeMessageHandle.
+	(createPeerMessage): Replaced PeerMessageHandle with PeerMessage.
+	(PeerInteraction): Replaced Peer with PeerHandle.
+	Replaced Socket with SocketHandle.
+	(addMessage): Replaced PeerMessage with PeerMessageHandle.
+	(receiveMessage): Replaced PeerMessage with PeerMessageHandle.
+	(receiveHandshake): Replaced HandshakeMessage with
+	HandshakeMessageHandle.
+	* src/PeerInteraction.cc
+	(PeerInteraction): Replaced Peer with PeerHandle.
+	Replaced Socket with SocketHandle.
+	(~PeerInteraction): Removed the deallocation of the elements of
+	messageQueue.
+	(MsgPushBack::operator()): Replaced PeerMessage with PeerMessageHandle.
+	(isSendingMessageInProgress): Replaced PeerMessage with
+	PeerMessageHandle.
+	(sendMessages): Use PeerMessageHandle. Removed try-catch block.
+	(addMessage): Replaced PeerMessage with PeerMessageHandle.
+	(rejectAllPieceMessageInQueue): Use PeerMessageHandle.
+	(rejectPieceMessageInQueue): Use PeerMessageHandle.
+	(abortPiece): Use PeerMessageHandle.
+	(receiveHandshake): Replaced HandshakeMessage with
+	HandshakeMessageHandle. Removed try-catch block.
+	(createHandshakeMessage): Replaced HandshakeMessage with
+	HandshakeMessageHandle.
+	(receiveMessage): Replaced PeerMessage with PeerMessageHandle.
+	Removed try-catch block.
+	(createPeerMessage): Replaced PeerMessage with PeerMessageHandle.
+	* src/HttpProxyResponseCommand.cc
+	(HttpProxyRequestCommand): Replaced Socket with SocketHandle.
+	* src/FtpTunnelResponseCommand.h
+	(FtpTunnelResponseCommand): Replaced Socket with SocketHandle.
+	* src/HttpConnection.cc
+	(HttpConnection): Replaced Socket with SocketHandle.
+	* src/PeerAbstractCommand.cc
+	(PeerAbstractCommand): Replaced Socket with SocketHandle.
+	(~PeerAbstractCommand): Removed the deallocation of socket.
+	Use disableReadCheckSocket, disableWriteCheckSocket.
+	(disableReadCheckSocket): New function.
+	(setReadCheckSocket): Replaced Socket with SocketHandle.
+	(disableWriteCheckSocket): New function.
+	(setWriteCheckSocket): Replaced Socket with SocketHandle.
+	* src/InitiateConnectionCommandFactory.h: Corrected indentation.
+	* src/FtpTunnelRequestCommand.cc
+	(FtpTunnelRequestCommand): Replaced Socket with SocketHandle.
+	(~FtpTunnelRequestCommand): Corrected indentation.
+	* src/DownloadCommand.h
+	(DownloadCommand): Replaced Socket with SocketHandle.
+	* src/PeerListenCommand.cc
+	(PeerListenCommand): Removed the initialization of socket.
+	(~PeerListenCommand): Removed the deallocation of socket.
+	(bindPort): Use SocketHandle.
+	(execute): Use SocketHandle and PeerHandle.
+	* src/FtpDowndloadCommand.cc
+	(FtpDownloadCommand): Replaced Socket with SocketHandle.
+	(~FtpDownloadCommand): Removed the deallocation of ctrlSocket.
+	* src/main.cc
+	(main): Corrected indentation.
+	* src/HttpInitiateConnectionCommand.cc
+	(HttpInitiateConnectionCommand): Replaced Socket with SocketHandle.
+	(executeInternal): Removed the allocation of socket.
+	* src/HttpRequestCommand.h
+	(HttpRequestCommand): Replaced Socket with SocketHandle.
+	* src/FtpNegotiationCommand.h
+	(dataSocket): Changed its type to SocketHandle.
+	(serverSocket): Changed its type to SocketHandle.
+	(FtpNegotiationCommand): Replaced Socket with SocketHandle.
+	* src/TorrentMan.h
+	(MAX_PEER_UPDATE): Removed.
+	(MAX_PEERS): New definition.
+	(Peers): The element is now of type PeerHandle.
+	(addPeer): Replaced Peer with PeerHandle. Removed 'duplicate' argument.
+	(getPeer): Replaced Peer with PeerHandle.
+	(deleteOldErrorPeers): Removed.
+	(deleteErrorPeer): New function.
+	(hasMissingPiece): Replaced Peer with PeerHandle.
+	(getMissingPieceIndex): Replaced Peer with PeerHandle.
+	(getMissingPiece): Replaced Peer with PeerHandle.
+	(getMissingFastPieceIndex): Replaced Peer with PeerHandle.
+	(getMissingFastPiece): Replaced Peer with PeerHandle.
+	(addActivePeer): Replaced Peer with PeerHandle.
+	(deleteActivePeer): Replaced Peer with PeerHandle.
+	Added a check for the return value of find.
+	* src/FtpTunnelResponseCommand.cc
+	(FtpTunnelResponseCommand): Replaced Socket with SocketHandle.
+	* src/FtpInitiateConnectionCommand.cc
+	(executeInternal): Removed the allocation of socket.
+	* src/DownloadEngine.h
+	(Sockets): An element is now of type SocketHandle.
+	(SockCmdMap): A key is of type SocketHandle, a value is of type int.
+	(CommandUuids): New type definition.
+	(rsockets): Changed its type to SockCmdMap.
+	(wsockets): Changed its type to SockCmdMap.
+	(addSocket): Rewritten.
+	(deleteSocket): Rewritten.
+	(addSocketForReadCheck): Rewritten.
+	(deleteSocketForReadCheck): Rewritten.
+	(addSocketForWriteCheck): Rewritten.
+	(deleteSocketForWriteCheck): Rewritten.
+	(PairFind): New template class.
+	* src/HttpDownloadCommand.h
+	(HttpDownloadCommand): Replaced Socket with SocketHandle.
+	* src/FtpConnection.cc
+	(FtpConnection): Replaced Socket with SocketHandle.
+	(sendPort): Removed the allocation of serverSocket. Removed try-catch
+	block.
+	* src/InitiateConnectionCommandFactory.cc
+	(DlAbortEx.h): Included DlAbortEx.h.
+	(createInitiateConnectionCommand): Throw exception if the protocol of
+	requested URI is not supported.
+	* src/Peer.cc
+	(nullPeer): Changed its type to PeerHandle.
+	(operator==): New function.
+	(operator!=): New function.
+	* src/Peer.h
+	(SharedHandle.h): Included SharedHandle.h.
+	(operator==): New function.
+	(operator!=): New function.
+	(Peer): Added the default constructor.
+	Use resetStatus() to initialize member variables.
+	(nullPeer): Removed.
+	* src/TrackerUpdateCommand.cc
+	(execute): Brushed up using SharedHandle. Replaced MAX_PEER_UPDATE
+	with MIN_PEERS.
+	* src/PeerListenCommand.h
+	(socket): Changed its type to SocketHandle.
+	* src/Command.h
+	(CommandUuid): New type definition.
+	(uuid): New variable.
+	(uuidGen): New variable.
+	(Command): Added the initialization of uuid.
+	(getUuid): New function.
+	* src/Socket.h
+	(Socket): Removed.
+	(SocketHandle): New type definition.
+	* src/DownloadEngine.h
+	(FindCommand): New function object.
+	(run): The portion of socket check was rewritten.
+	(SetDescriptor): New function object.
+	(AccumulateActiveCommandUuid): New function object.
+	(waitData): Rewritten.
+	(addSocket): Rewritten.
+	(deleteSocket): Rewritten.
+	(addSocketForReadCheck): Rewritten.
+	(addSocketForWriteCheck): Rewritten.
+	(deleteSocketForReadCheck): Rewritten.
+	(deleteSocketForWriteCheck): Rewritten.
+	* src/HttpProxyResponseCommand.h
+	(HttpProxyResponseCommand): Replaced Socket with SocketHandle.
+	* src/HttpConnection.h
+	(socket): Changed its type to SocketHandle.
+	(HttpConnection): Replaced Socket with SocketHandle.
+	* src/PeerInitiateConnectionCommand.cc
+	(PeerInitiateConnectionCommand): Replaced Peer with PeerHandle.
+	(executeInternal): Removed the allocation of socket.
+	(prepareForNextPeer): Use PeerHandle.
+	* src/PeerMessage.h
+	(peer): Changed its type to PeerHandle.
+	(getPeer): Replaced Peer with PeerHandle.
+	(setPeer): Replaced Peer with PeerHandle.
+	* src/DownloadCommand.cc
+	(DownloadCommand): Replaced Socket with SocketHandle.
+	* src/FtpConnection.h
+	(socket): Changed its type to SocketHandle.
+	(FtpConnection): Replaced Socket with SocketHandle.
+	(sendPort); Replaced Socket with SocketHandle.
+	* src/FtpDowndloadCommand.h
+	(ctrlSocket): Changed its type to SocketHandle.
+	(FtpDownloadCommand): Replaced Socket with SocketHandle.
+	* src/HttpProxyRequestCommand.cc
+	(HttpProxyRequestCommand): Replaced Socket with SocketHandle.
+	* src/FtpTunnelRequestCommand.h
+	(FtpTunnelRequestCommand): Replaced Socket with SocketHandle.
+	
+	etc
+	
+	* src/PeerChokeCommand.h
+	(setAllPeerChoked): Removed.
+	(setAllPeerResetDelta): Removed.
+	* src/PeerChokeCommand.cc
+	(setAllPeerChoked): Removed.
+	(ChokePeer): New function object.
+	(setAllPeerResetDelta): Removed.
+	(ResetDelta): New function object.
+	(orderByDownloadRate): Fixed a bug: use DowloadFaster, not UploadFaster
+	(execute): Show download speed when the local node is a seeder.
+	setAllPeerChoked and setAllPeerResetDelta were rewritten
+	using STL.
+	* src/TrackerWatcherCommand.h
+	(MIN_PEERS): Removed.
+	* src/TorrentMan.cc
+	(getPeer): Replaced MAX_PEER_UPDATE with MIN_PEERS.
+	
 2006-07-07  Tatsuhiro Tsujikawa  <tujikawa at rednoah dot com>
 
 	To fix the bug that .aria2 file is not saved if downloading is stopped
diff --git a/TODO b/TODO
index b590fc88..881056d8 100644
--- a/TODO
+++ b/TODO
@@ -11,3 +11,4 @@
 * Refacturing HttpConnection and FtpConnection
 * Query resource by location
 * Log version
+* List available os, version, etc for metalink
\ No newline at end of file
diff --git a/src/AbstractCommand.cc b/src/AbstractCommand.cc
index a622959a..ffd72393 100644
--- a/src/AbstractCommand.cc
+++ b/src/AbstractCommand.cc
@@ -28,24 +28,18 @@
 #include "SleepCommand.h"
 #include "prefs.h"
 
-AbstractCommand::AbstractCommand(int cuid, Request* req, DownloadEngine* e, const Socket* s):
-  Command(cuid), req(req), e(e), checkSocketIsReadable(false), checkSocketIsWritable(false) {
-
-  if(s != NULL) {
-    socket = new Socket(*s);
-    setReadCheckSocket(socket);
-  } else {
-    socket = NULL;
-  }
+AbstractCommand::AbstractCommand(int cuid, Request* req, DownloadEngine* e,
+				 const SocketHandle& s):
+  Command(cuid), req(req), e(e), socket(s),
+  checkSocketIsReadable(false), checkSocketIsWritable(false) {
+  
+  setReadCheckSocket(socket);
   timeout = this->e->option->getAsInt(PREF_TIMEOUT);
 }
 
 AbstractCommand::~AbstractCommand() {
-  setReadCheckSocket(NULL);
-  setWriteCheckSocket(NULL);
-  if(socket != NULL) {
-    delete(socket);
-  }
+  disableReadCheckSocket();
+  disableWriteCheckSocket();
 }
 
 bool AbstractCommand::execute() {
@@ -124,44 +118,52 @@ void AbstractCommand::onAbort(Exception* ex) {
   e->segmentMan->unregisterId(cuid);
 }
 
-void AbstractCommand::setReadCheckSocket(Socket* socket) {
-  if(socket == NULL) {
-    if(checkSocketIsReadable) {
-      e->deleteSocketForReadCheck(readCheckTarget);
-      checkSocketIsReadable = false;
-      readCheckTarget = NULL;
-    }
+void AbstractCommand::disableReadCheckSocket() {
+  if(checkSocketIsReadable) {
+    e->deleteSocketForReadCheck(readCheckTarget, getUuid());
+    checkSocketIsReadable = false;
+    readCheckTarget = SocketHandle();
+  }  
+}
+
+void AbstractCommand::setReadCheckSocket(const SocketHandle& socket) {
+  if(!socket->isOpen()) {
+    disableReadCheckSocket();
   } else {
     if(checkSocketIsReadable) {
       if(readCheckTarget != socket) {
-	e->deleteSocketForReadCheck(readCheckTarget);
-	e->addSocketForReadCheck(socket, this);
+	e->deleteSocketForReadCheck(readCheckTarget, getUuid());
+	e->addSocketForReadCheck(socket, getUuid());
 	readCheckTarget = socket;
       }
     } else {
-      e->addSocketForReadCheck(socket, this);
+      e->addSocketForReadCheck(socket, getUuid());
       checkSocketIsReadable = true;
       readCheckTarget = socket;
     }
   }
 }
 
-void AbstractCommand::setWriteCheckSocket(Socket* socket) {
-  if(socket == NULL) {
-    if(checkSocketIsWritable) {
-      e->deleteSocketForWriteCheck(writeCheckTarget);
-      checkSocketIsWritable = false;
-      writeCheckTarget = NULL;
-    }
+void AbstractCommand::disableWriteCheckSocket() {
+  if(checkSocketIsWritable) {
+    e->deleteSocketForWriteCheck(writeCheckTarget, getUuid());
+    checkSocketIsWritable = false;
+    writeCheckTarget = SocketHandle();
+  }
+}
+
+void AbstractCommand::setWriteCheckSocket(const SocketHandle& socket) {
+  if(!socket->isOpen()) {
+    disableWriteCheckSocket();
   } else {
     if(checkSocketIsWritable) {
       if(writeCheckTarget != socket) {
-	e->deleteSocketForWriteCheck(writeCheckTarget);
-	e->addSocketForWriteCheck(socket, this);
+	e->deleteSocketForWriteCheck(writeCheckTarget, getUuid());
+	e->addSocketForWriteCheck(socket, getUuid());
 	writeCheckTarget = socket;
       }
     } else {
-      e->addSocketForWriteCheck(socket, this);
+      e->addSocketForWriteCheck(socket, getUuid());
       checkSocketIsWritable = true;
       writeCheckTarget = socket;
     }
diff --git a/src/AbstractCommand.h b/src/AbstractCommand.h
index 6eb6e9f4..6d84013d 100644
--- a/src/AbstractCommand.h
+++ b/src/AbstractCommand.h
@@ -35,23 +35,25 @@ private:
 protected:
   Request* req;
   DownloadEngine* e;
-  Socket* socket;
+  SocketHandle socket;
 
   void tryReserved();
   virtual bool prepareForRetry(int wait);
   virtual void onAbort(Exception* ex);
   virtual bool executeInternal(Segment segment) = 0;
 
-  void setReadCheckSocket(Socket* socket);
-  void setWriteCheckSocket(Socket* socket);
+  void setReadCheckSocket(const SocketHandle& socket);
+  void setWriteCheckSocket(const SocketHandle& socket);
+  void disableReadCheckSocket();
+  void disableWriteCheckSocket();
   void setTimeout(int timeout) { this->timeout = timeout; }
 private:
   bool checkSocketIsReadable;
   bool checkSocketIsWritable;
-  Socket* readCheckTarget;
-  Socket* writeCheckTarget;
+  SocketHandle readCheckTarget;
+  SocketHandle writeCheckTarget;
 public:
-  AbstractCommand(int cuid, Request* req, DownloadEngine* e, const Socket* s= NULL);
+  AbstractCommand(int cuid, Request* req, DownloadEngine* e, const SocketHandle& s = SocketHandle());
   virtual ~AbstractCommand();
   bool execute();
 };
diff --git a/src/Command.h b/src/Command.h
index 4b0639cd..dd06a420 100644
--- a/src/Command.h
+++ b/src/Command.h
@@ -25,18 +25,24 @@
 #include "common.h"
 #include "LogFactory.h"
 
+typedef int CommandUuid;
+
 class Command {
+private:
+  CommandUuid uuid;
+  static int uuidGen;
 protected:
   int cuid;
   const Logger* logger;
 public:
-  Command(int cuid):cuid(cuid) {
+  Command(int cuid):uuid(uuidGen++), cuid(cuid) {
     logger = LogFactory::getInstance();
   }
   virtual ~Command() {}
   virtual bool execute() = 0;
 
   int getCuid() const { return cuid; }
+  const CommandUuid& getUuid() const { return uuid; }
 };
 
 #endif // _D_COMMAND_H_
diff --git a/src/DownloadCommand.cc b/src/DownloadCommand.cc
index 98b117c6..441b00de 100644
--- a/src/DownloadCommand.cc
+++ b/src/DownloadCommand.cc
@@ -27,7 +27,10 @@
 #include "InitiateConnectionCommandFactory.h"
 #include "message.h"
 
-DownloadCommand::DownloadCommand(int cuid, Request* req, DownloadEngine* e, const Socket* s):AbstractCommand(cuid, req, e, s), lastSize(0) {}
+DownloadCommand::DownloadCommand(int cuid, Request* req, DownloadEngine* e,
+				 const SocketHandle& s):
+  AbstractCommand(cuid, req, e, s), lastSize(0) {
+}
 
 DownloadCommand::~DownloadCommand() {}
 
diff --git a/src/DownloadCommand.h b/src/DownloadCommand.h
index b1f4d2a0..9f10de02 100644
--- a/src/DownloadCommand.h
+++ b/src/DownloadCommand.h
@@ -38,7 +38,8 @@ protected:
   bool prepareForRetry(int wait);
   bool prepareForNextSegment();
 public:
-  DownloadCommand(int cuid, Request* req, DownloadEngine* e, const Socket* s);
+  DownloadCommand(int cuid, Request* req, DownloadEngine* e,
+		  const SocketHandle& s);
   virtual ~DownloadCommand();
 
   virtual TransferEncoding* getTransferEncoding(const string& transferEncoding) = 0;
diff --git a/src/DownloadEngine.cc b/src/DownloadEngine.cc
index e2bef95f..5b0469a7 100644
--- a/src/DownloadEngine.cc
+++ b/src/DownloadEngine.cc
@@ -47,10 +47,26 @@ void DownloadEngine::cleanQueue() {
   commands.clear();
 }
 
+
+class FindCommand {
+private:
+  CommandUuid uuid;
+public:
+  FindCommand(const CommandUuid& uuid):uuid(uuid) {}
+
+  bool operator()(const Command* command) {
+    if(command->getUuid() == uuid) {
+      return true;
+    } else {
+      return false;
+    }
+  }
+};
+
 void DownloadEngine::run() {
   initStatistics();
   Time cp;
-  Sockets activeSockets;
+  CommandUuids activeCommandUuids;
   while(!commands.empty()) {
     if(cp.elapsed(1)) {
       cp.reset();
@@ -59,27 +75,26 @@ void DownloadEngine::run() {
 	Command* com = commands.front();
 	commands.pop_front();
 	if(com->execute()) {
-	  delete(com);
+	  delete com;
 	}
       }
     } else {
-      for(Sockets::iterator itr = activeSockets.begin();
-	  itr != activeSockets.end(); itr++) {
-	Socket* socket = *itr;
-	SockCmdMap::iterator mapItr = sockCmdMap.find(socket);
-	if(mapItr != sockCmdMap.end()) {
-	  Command* com = (*mapItr).second;
-	  commands.erase(remove(commands.begin(), commands.end(), com));
-	  if(com->execute()) {
-	    delete(com);
-	  }
+      for(CommandUuids::iterator itr = activeCommandUuids.begin();
+	  itr != activeCommandUuids.end(); itr++) {
+	Commands::iterator comItr = find_if(commands.begin(), commands.end(),
+					    FindCommand(*itr));
+	assert(comItr != commands.end());
+	Command* com = *comItr;
+	commands.erase(comItr);
+	if(com->execute()) {
+	  delete com;
 	}
       }
     }
     afterEachIteration();
-    activeSockets.clear();
+    activeCommandUuids.clear();
     if(!noWait && !commands.empty()) {
-      waitData(activeSockets);
+      waitData(activeCommandUuids);
     }
     noWait = false;
     calculateStatistics();
@@ -96,7 +111,40 @@ void DownloadEngine::shortSleep() const {
   select(0, &rfds, NULL, NULL, &tv);
 }
 
-void DownloadEngine::waitData(Sockets& activeSockets) {
+class SetDescriptor {
+private:
+  fd_set* fds_ptr;
+  int* max_ptr;
+public:
+  SetDescriptor(int* max_ptr, fd_set* fds_ptr)
+    :fds_ptr(fds_ptr), max_ptr(max_ptr) {}
+
+  void operator()(const pair<SocketHandle, CommandUuid>& pa) {
+    int fd = pa.first->getSockfd();
+    FD_SET(fd, fds_ptr);
+    if(*max_ptr < fd) {
+      *max_ptr = fd;
+    }
+  }
+};
+
+class AccumulateActiveCommandUuid {
+private:
+  CommandUuids* activeCommandUuids_ptr;
+  fd_set* fds_ptr;
+public:
+  AccumulateActiveCommandUuid(CommandUuids* activeCommandUuids_ptr,
+			      fd_set* fds_ptr)
+    :activeCommandUuids_ptr(activeCommandUuids_ptr), fds_ptr(fds_ptr) {}
+
+  void operator()(const pair<SocketHandle, CommandUuid>& pa) {
+    if(FD_ISSET(pa.first->getSockfd(), fds_ptr)) {
+      activeCommandUuids_ptr->push_back(pa.second);
+    }
+  }
+};
+
+void DownloadEngine::waitData(CommandUuids& activeCommandUuids) {
   fd_set rfds;
   fd_set wfds;
   int retval = 0;
@@ -106,18 +154,9 @@ void DownloadEngine::waitData(Sockets& activeSockets) {
     FD_ZERO(&rfds);
     FD_ZERO(&wfds);
     int max = 0;
-    for(Sockets::iterator itr = rsockets.begin(); itr != rsockets.end(); itr++) {
-      FD_SET((*itr)->getSockfd(), &rfds);
-      if(max < (*itr)->getSockfd()) {
-	max = (*itr)->getSockfd();
-      }
-    }
-    for(Sockets::iterator itr = wsockets.begin(); itr != wsockets.end(); itr++) {
-      FD_SET((*itr)->getSockfd(), &wfds);
-      if(max < (*itr)->getSockfd()) {
-	max = (*itr)->getSockfd();
-      }
-    }
+    for_each(rsockmap.begin(), rsockmap.end(), SetDescriptor(&max, &rfds));
+    for_each(wsockmap.begin(), wsockmap.end(), SetDescriptor(&max, &wfds));
+
     tv.tv_sec = 1;
     tv.tv_usec = 0;
     retval = select(max+1, &rfds, &wfds, NULL, &tv);
@@ -126,64 +165,60 @@ void DownloadEngine::waitData(Sockets& activeSockets) {
     }
   }
   if(retval > 0) {
-    for(Sockets::iterator itr = rsockets.begin(); itr != rsockets.end(); itr++) {
-      if(FD_ISSET((*itr)->getSockfd(), &rfds)) {
-	activeSockets.push_back(*itr);
-      }
-    }
-    for(Sockets::iterator itr = wsockets.begin(); itr != wsockets.end(); itr++) {
-      if(FD_ISSET((*itr)->getSockfd(), &wfds)) {
-	activeSockets.push_back(*itr);
-      }
-    }
-    sort(activeSockets.begin(), activeSockets.end());
-    activeSockets.erase(unique(activeSockets.begin(), activeSockets.end()), activeSockets.end());
+    for_each(rsockmap.begin(), rsockmap.end(),
+	     AccumulateActiveCommandUuid(&activeCommandUuids, &rfds));
+    for_each(wsockmap.begin(), wsockmap.end(),
+	     AccumulateActiveCommandUuid(&activeCommandUuids, &wfds));
+    sort(activeCommandUuids.begin(), activeCommandUuids.end());
+    activeCommandUuids.erase(unique(activeCommandUuids.begin(),
+				activeCommandUuids.end()),
+			 activeCommandUuids.end());
   }
 }
 
-bool DownloadEngine::addSocket(Sockets& sockets, Socket* socket, Command* command) {
-  Sockets::iterator itr = find(sockets.begin(),
-			       sockets.end(),
-			       socket);
-  if(itr == sockets.end()) {
-    sockets.push_back(socket);
-    SockCmdMap::value_type vt(socket, command);
-    sockCmdMap.insert(vt);
+bool DownloadEngine::addSocket(SockCmdMap& sockmap,
+			       const SocketHandle& socket,
+			       const CommandUuid& commandUuid) {
+  SockCmdMap::iterator itr = find_if(sockmap.begin(), sockmap.end(),
+				     PairFind<SocketHandle, CommandUuid>(socket, commandUuid));
+  if(itr == sockmap.end()) {
+    SockCmdMap::value_type vt(socket, commandUuid);
+    sockmap.insert(vt);
     return true;
   } else {
     return false;
   }
 }
 
-bool DownloadEngine::deleteSocket(Sockets& sockets, Socket* socket) {
-  Sockets::iterator itr = find(sockets.begin(),
-			       sockets.end(),
-			       socket);
-  if(itr != sockets.end()) {
-    sockets.erase(itr);
-    SockCmdMap::iterator mapItr = sockCmdMap.find(socket);
-    if(mapItr != sockCmdMap.end()) {
-      sockCmdMap.erase(mapItr);
-    }
-    return true;
-  } else {
+bool DownloadEngine::deleteSocket(SockCmdMap& sockmap,
+				  const SocketHandle& socket,
+				  const CommandUuid& commandUuid) {
+  SockCmdMap::iterator itr = find_if(sockmap.begin(), sockmap.end(),
+				     PairFind<SocketHandle, CommandUuid>(socket, commandUuid));
+  if(itr == sockmap.end()) {
     return false;
+  } else {
+    sockmap.erase(itr);
+    return true;
   }
 }
 
-bool DownloadEngine::addSocketForReadCheck(Socket* socket, Command* command) {
-  return addSocket(rsockets, socket, command);
+bool DownloadEngine::addSocketForReadCheck(const SocketHandle& socket,
+					   const CommandUuid& commandUuid) {
+  return addSocket(rsockmap, socket, commandUuid);
 }
 
-bool DownloadEngine::deleteSocketForReadCheck(Socket* socket) {
-  return deleteSocket(rsockets , socket);
+bool DownloadEngine::deleteSocketForReadCheck(const SocketHandle& socket,
+					      const CommandUuid& commandUuid) {
+  return deleteSocket(rsockmap, socket, commandUuid);
 }
 
-bool DownloadEngine::addSocketForWriteCheck(Socket* socket, Command* command) {
-  return addSocket(wsockets, socket, command);
+bool DownloadEngine::addSocketForWriteCheck(const SocketHandle& socket,
+					    const CommandUuid& commandUuid) {
+  return addSocket(wsockmap, socket, commandUuid);
 }
 
-bool DownloadEngine::deleteSocketForWriteCheck(Socket* socket) {
-  return deleteSocket(wsockets, socket);
+bool DownloadEngine::deleteSocketForWriteCheck(const SocketHandle& socket,
+					       const CommandUuid& commandUuid) {
+  return deleteSocket(wsockmap, socket, commandUuid);
 }
-
diff --git a/src/DownloadEngine.h b/src/DownloadEngine.h
index dd9d10fc..9acbeda4 100644
--- a/src/DownloadEngine.h
+++ b/src/DownloadEngine.h
@@ -29,20 +29,22 @@
 #include "Logger.h"
 #include "Option.h"
 
-typedef deque<Socket*> Sockets;
+typedef deque<SocketHandle> Sockets;
 typedef deque<Command*> Commands;
-typedef multimap<Socket*, Command*> SockCmdMap;
+typedef deque<CommandUuid> CommandUuids;
+typedef multimap<SocketHandle, int> SockCmdMap;
 
 class DownloadEngine {
 private:
-  void waitData(Sockets& activeSockets);
-  Sockets rsockets;
-  Sockets wsockets;
-  SockCmdMap sockCmdMap;
-
+  void waitData(CommandUuids& activeCommandUuids);
+  SockCmdMap rsockmap;
+  SockCmdMap wsockmap;
+  
   void shortSleep() const;
-  bool addSocket(Sockets& sockets, Socket* socket, Command* command);
-  bool deleteSocket(Sockets& sockets, Socket* socket);
+  bool addSocket(SockCmdMap& sockmap, const SocketHandle& socket,
+		 const CommandUuid& commandUuid);
+  bool deleteSocket(SockCmdMap& sockmap, const SocketHandle& socket,
+		    const CommandUuid& commandUuid);
 protected:
   const Logger* logger;
   virtual void initStatistics() = 0;
@@ -62,12 +64,33 @@ public:
 
   void cleanQueue();
 
-  bool addSocketForReadCheck(Socket* socket, Command* command);
-  bool deleteSocketForReadCheck(Socket* socket);
-  bool addSocketForWriteCheck(Socket* socket, Command* command);
-  bool deleteSocketForWriteCheck(Socket* socket);
+  bool addSocketForReadCheck(const SocketHandle& socket,
+			     const CommandUuid& commandUuid);
+  bool deleteSocketForReadCheck(const SocketHandle& socket,
+				const CommandUuid& commandUuid);
+  bool addSocketForWriteCheck(const SocketHandle& socket,
+			      const CommandUuid& commandUuid);
+  bool deleteSocketForWriteCheck(const SocketHandle& socket,
+				 const CommandUuid& command);
   
 };
 
+template<class T1, class T2>
+class PairFind {
+private:
+  T1 first;
+  T2 second;
+public:
+  PairFind(T1 t1, T2 t2):first(t1), second(t2) {}
+
+  bool operator()(const pair<T1, T2>& pa) {
+    if(pa.first == first && pa.second == second) {
+      return true;
+    } else {
+      return false;
+    }
+  }
+};
+
 #endif // _D_DOWNLOAD_ENGINE_H_
 
diff --git a/src/FtpConnection.cc b/src/FtpConnection.cc
index 0f947636..ba8e2000 100644
--- a/src/FtpConnection.cc
+++ b/src/FtpConnection.cc
@@ -27,7 +27,9 @@
 #include "prefs.h"
 #include "LogFactory.h"
 
-FtpConnection::FtpConnection(int cuid, const Socket* socket, const Request* req, const Option* op):cuid(cuid), socket(socket), req(req), option(op) {
+FtpConnection::FtpConnection(int cuid, const SocketHandle& socket,
+			     const Request* req, const Option* op)
+  :cuid(cuid), socket(socket), req(req), option(op) {
   logger = LogFactory::getInstance();
 }
 
@@ -75,27 +77,22 @@ void FtpConnection::sendPasv() const {
   socket->writeData(request);
 }
 
-Socket* FtpConnection::sendPort() const {
-  Socket* serverSocket = new Socket();
-  try {
-    serverSocket->beginListen();
-
-    pair<string, int> addrinfo;
-    socket->getAddrInfo(addrinfo);
-    int ipaddr[4]; 
-    sscanf(addrinfo.first.c_str(), "%d.%d.%d.%d",
-	   &ipaddr[0], &ipaddr[1], &ipaddr[2], &ipaddr[3]);
-    serverSocket->getAddrInfo(addrinfo);
-    string request = "PORT "+
-      Util::itos(ipaddr[0])+","+Util::itos(ipaddr[1])+","+
-      Util::itos(ipaddr[2])+","+Util::itos(ipaddr[3])+","+
-      Util::itos(addrinfo.second/256)+","+Util::itos(addrinfo.second%256)+"\r\n";
-    logger->info(MSG_SENDING_REQUEST, cuid, request.c_str());
-    socket->writeData(request);
-  } catch (Exception* ex) {
-    delete serverSocket;
-    throw;
-  }
+SocketHandle FtpConnection::sendPort() const {
+  SocketHandle serverSocket;
+  serverSocket->beginListen();
+  
+  pair<string, int> addrinfo;
+  socket->getAddrInfo(addrinfo);
+  int ipaddr[4]; 
+  sscanf(addrinfo.first.c_str(), "%d.%d.%d.%d",
+	 &ipaddr[0], &ipaddr[1], &ipaddr[2], &ipaddr[3]);
+  serverSocket->getAddrInfo(addrinfo);
+  string request = "PORT "+
+    Util::itos(ipaddr[0])+","+Util::itos(ipaddr[1])+","+
+    Util::itos(ipaddr[2])+","+Util::itos(ipaddr[3])+","+
+    Util::itos(addrinfo.second/256)+","+Util::itos(addrinfo.second%256)+"\r\n";
+  logger->info(MSG_SENDING_REQUEST, cuid, request.c_str());
+  socket->writeData(request);
   return serverSocket;
 }
 
diff --git a/src/FtpConnection.h b/src/FtpConnection.h
index 8d91b932..1dd36a8e 100644
--- a/src/FtpConnection.h
+++ b/src/FtpConnection.h
@@ -35,7 +35,7 @@ using namespace std;
 class FtpConnection {
 private:
   int cuid;
-  const Socket* socket;
+  SocketHandle socket;
   const Request* req;
   const Option* option;
   const Logger* logger;
@@ -46,7 +46,8 @@ private:
   bool isEndOfResponse(int status, const string& response) const;
   bool bulkReceiveResponse(pair<int, string>& response);
 public:
-  FtpConnection(int cuid, const Socket* socket, const Request* req, const Option* op);
+  FtpConnection(int cuid, const SocketHandle& socket,
+		const Request* req, const Option* op);
   ~FtpConnection();
   void sendUser() const;
   void sendPass() const;
@@ -54,7 +55,7 @@ public:
   void sendCwd() const;
   void sendSize() const;
   void sendPasv() const;
-  Socket* sendPort() const;
+  SocketHandle sendPort() const;
   void sendRest(const Segment& segment) const;
   void sendRetr() const;
 
diff --git a/src/FtpDownloadCommand.cc b/src/FtpDownloadCommand.cc
index db9a492a..25368973 100644
--- a/src/FtpDownloadCommand.cc
+++ b/src/FtpDownloadCommand.cc
@@ -21,17 +21,13 @@
 /* copyright --> */
 #include "FtpDownloadCommand.h"
 
-FtpDownloadCommand::FtpDownloadCommand(int cuid, Request* req, DownloadEngine* e, const Socket* dataSocket, const Socket* ctrlSocket):
-  DownloadCommand(cuid, req, e, dataSocket)
-{
-  this->ctrlSocket = new Socket(*ctrlSocket);
-}
+FtpDownloadCommand::FtpDownloadCommand(int cuid, Request* req,
+				       DownloadEngine* e,
+				       const SocketHandle& dataSocket,
+				       const SocketHandle& ctrlSocket)
+  :DownloadCommand(cuid, req, e, dataSocket), ctrlSocket(ctrlSocket) {}
 
-FtpDownloadCommand::~FtpDownloadCommand() {
-  if(ctrlSocket != NULL) {
-    delete ctrlSocket;
-  }
-}
+FtpDownloadCommand::~FtpDownloadCommand() {}
 
 TransferEncoding* FtpDownloadCommand::getTransferEncoding(const string& name) {
   return NULL;
diff --git a/src/FtpDownloadCommand.h b/src/FtpDownloadCommand.h
index 4e41782b..74ca7382 100644
--- a/src/FtpDownloadCommand.h
+++ b/src/FtpDownloadCommand.h
@@ -26,9 +26,11 @@
 
 class FtpDownloadCommand : public DownloadCommand {
 private:
-  Socket* ctrlSocket;
+  SocketHandle ctrlSocket;
 public:
-  FtpDownloadCommand(int cuid, Request* req, DownloadEngine* e, const Socket* dataSocket, const Socket* ctrlSocket);
+  FtpDownloadCommand(int cuid, Request* req, DownloadEngine* e,
+		     const SocketHandle& dataSocket,
+		     const SocketHandle& ctrlSocket);
   ~FtpDownloadCommand();
 
   TransferEncoding* getTransferEncoding(const string& name);
diff --git a/src/FtpInitiateConnectionCommand.cc b/src/FtpInitiateConnectionCommand.cc
index 7f12e598..2a67222e 100644
--- a/src/FtpInitiateConnectionCommand.cc
+++ b/src/FtpInitiateConnectionCommand.cc
@@ -44,7 +44,6 @@ bool FtpInitiateConnectionCommand::executeInternal(Segment segment) {
     }
   }
 
-  socket = new Socket();
   Command* command;
   if(useHttpProxy()) {
     logger->info(MSG_CONNECTING_TO_SERVER, cuid,
diff --git a/src/FtpNegotiationCommand.cc b/src/FtpNegotiationCommand.cc
index af0565b9..67b08f6b 100644
--- a/src/FtpNegotiationCommand.cc
+++ b/src/FtpNegotiationCommand.cc
@@ -26,22 +26,17 @@
 #include "message.h"
 #include "prefs.h"
 
-FtpNegotiationCommand::FtpNegotiationCommand(int cuid, Request* req, DownloadEngine* e, const Socket* s):
-  AbstractCommand(cuid, req, e, s),
-  dataSocket(NULL), serverSocket(NULL), sequence(SEQ_RECV_GREETING)
+FtpNegotiationCommand::FtpNegotiationCommand(int cuid, Request* req,
+					     DownloadEngine* e,
+					     const SocketHandle& s):
+  AbstractCommand(cuid, req, e, s), sequence(SEQ_RECV_GREETING)
 {
   ftp = new FtpConnection(cuid, socket, req, e->option);
-  setReadCheckSocket(NULL);
+  disableReadCheckSocket();
   setWriteCheckSocket(socket);
 }
 
 FtpNegotiationCommand::~FtpNegotiationCommand() {
-  if(dataSocket != NULL) {
-    delete dataSocket;
-  }
-  if(serverSocket != NULL) {
-    delete serverSocket;
-  }
   delete ftp;
 }
 
@@ -50,7 +45,8 @@ bool FtpNegotiationCommand::executeInternal(Segment segment) {
   if(sequence == SEQ_RETRY) {
     return prepareForRetry(0);
   } else if(sequence == SEQ_NEGOTIATION_COMPLETED) {
-    FtpDownloadCommand* command = new FtpDownloadCommand(cuid, req, e, dataSocket, socket);
+    FtpDownloadCommand* command =
+      new FtpDownloadCommand(cuid, req, e, dataSocket, socket);
     e->commands.push_back(command);
     return true;
   } else {
@@ -71,7 +67,7 @@ bool FtpNegotiationCommand::recvGreeting() {
   sequence = SEQ_SEND_USER;
 
   setReadCheckSocket(socket);
-  setWriteCheckSocket(NULL);
+  disableWriteCheckSocket();
 
   return true;
 }
@@ -219,14 +215,12 @@ bool FtpNegotiationCommand::recvPasv() {
     throw new DlRetryEx(EX_BAD_STATUS, status);
   }
   // make a data connection to the server.
-  dataSocket = new Socket();
-
   logger->info(MSG_CONNECTING_TO_SERVER, cuid,
 	       dest.first.c_str(),
 	       dest.second);
   dataSocket->establishConnection(dest.first, dest.second);
 
-  setReadCheckSocket(NULL);
+  disableReadCheckSocket();
   setWriteCheckSocket(dataSocket);
 
   sequence = SEQ_SEND_REST_PASV;
@@ -236,7 +230,7 @@ bool FtpNegotiationCommand::recvPasv() {
 bool FtpNegotiationCommand::sendRestPasv(const Segment& segment) {
   dataSocket->setBlockingMode();
   setReadCheckSocket(socket);
-  setWriteCheckSocket(NULL);
+  disableWriteCheckSocket();
   return sendRest(segment);
 }
 
@@ -274,7 +268,7 @@ bool FtpNegotiationCommand::recvRetr() {
     throw new DlRetryEx(EX_BAD_STATUS, status);
   }
   if(e->option->get(PREF_FTP_PASV_ENABLED) != V_TRUE) {
-    assert(serverSocket);
+    assert(serverSocket->getSockfd() != -1);
     dataSocket = serverSocket->acceptConnection();
   }
   sequence = SEQ_NEGOTIATION_COMPLETED;
diff --git a/src/FtpNegotiationCommand.h b/src/FtpNegotiationCommand.h
index 930fab0e..e89317d6 100644
--- a/src/FtpNegotiationCommand.h
+++ b/src/FtpNegotiationCommand.h
@@ -73,14 +73,15 @@ private:
   bool recvRetr();
   bool processSequence(const Segment& segment);
 
-  Socket* dataSocket;
-  Socket* serverSocket;
+  SocketHandle dataSocket;
+  SocketHandle serverSocket;
   int sequence;
   FtpConnection* ftp;
 protected:
   bool executeInternal(Segment segment);
 public:
-  FtpNegotiationCommand(int cuid, Request* req, DownloadEngine* e, const Socket* s);
+  FtpNegotiationCommand(int cuid, Request* req, DownloadEngine* e,
+			const SocketHandle& s);
   ~FtpNegotiationCommand();
 };
 
diff --git a/src/FtpTunnelRequestCommand.cc b/src/FtpTunnelRequestCommand.cc
index 86018070..24a8049b 100644
--- a/src/FtpTunnelRequestCommand.cc
+++ b/src/FtpTunnelRequestCommand.cc
@@ -23,9 +23,12 @@
 #include "FtpTunnelResponseCommand.h"
 #include "HttpConnection.h"
 
-FtpTunnelRequestCommand::FtpTunnelRequestCommand(int cuid, Request* req, DownloadEngine* e, const Socket* s):AbstractCommand(cuid, req, e, s) {
-  setReadCheckSocket(NULL);
-  setWriteCheckSocket(NULL);
+FtpTunnelRequestCommand::FtpTunnelRequestCommand(int cuid, Request* req,
+						 DownloadEngine* e,
+						 const SocketHandle& s)
+  :AbstractCommand(cuid, req, e, s) {
+  disableReadCheckSocket();
+  disableWriteCheckSocket();
 }
 
 FtpTunnelRequestCommand::~FtpTunnelRequestCommand() {}
@@ -35,7 +38,8 @@ bool FtpTunnelRequestCommand::executeInternal(Segment segment) {
   HttpConnection httpConnection(cuid, socket, req, e->option);
   httpConnection.sendProxyRequest();
 
-  FtpTunnelResponseCommand* command = new FtpTunnelResponseCommand(cuid, req, e, socket);
+  FtpTunnelResponseCommand* command
+    = new FtpTunnelResponseCommand(cuid, req, e, socket);
   e->commands.push_back(command);
   return true;
 }
diff --git a/src/FtpTunnelRequestCommand.h b/src/FtpTunnelRequestCommand.h
index 35df06e1..b02d1806 100644
--- a/src/FtpTunnelRequestCommand.h
+++ b/src/FtpTunnelRequestCommand.h
@@ -28,7 +28,8 @@ class FtpTunnelRequestCommand : public AbstractCommand {
 protected:
   bool executeInternal(Segment segment);
 public:
-  FtpTunnelRequestCommand(int cuid, Request* req, DownloadEngine* e, const Socket* s);
+  FtpTunnelRequestCommand(int cuid, Request* req, DownloadEngine* e,
+			  const SocketHandle& s);
   ~FtpTunnelRequestCommand();
 };
 
diff --git a/src/FtpTunnelResponseCommand.cc b/src/FtpTunnelResponseCommand.cc
index 0efe840f..d0e63888 100644
--- a/src/FtpTunnelResponseCommand.cc
+++ b/src/FtpTunnelResponseCommand.cc
@@ -24,7 +24,10 @@
 #include "DlRetryEx.h"
 #include "message.h"
 
-FtpTunnelResponseCommand::FtpTunnelResponseCommand(int cuid, Request* req, DownloadEngine* e, const Socket* s):AbstractCommand(cuid, req, e, s) {
+FtpTunnelResponseCommand::FtpTunnelResponseCommand(int cuid, Request* req,
+						   DownloadEngine* e,
+						   const SocketHandle& s)
+  :AbstractCommand(cuid, req, e, s) {
   http = new HttpConnection(cuid, socket, req, e->option);
 }
 
@@ -43,7 +46,8 @@ bool FtpTunnelResponseCommand::executeInternal(Segment segment) {
   if(status != 200) {
     throw new DlRetryEx(EX_PROXY_CONNECTION_FAILED);
   }
-  FtpNegotiationCommand* command = new FtpNegotiationCommand(cuid, req, e, socket);
+  FtpNegotiationCommand* command
+    = new FtpNegotiationCommand(cuid, req, e, socket);
   e->commands.push_back(command);
   return true;
 }
diff --git a/src/FtpTunnelResponseCommand.h b/src/FtpTunnelResponseCommand.h
index bf304f29..7d0e19ae 100644
--- a/src/FtpTunnelResponseCommand.h
+++ b/src/FtpTunnelResponseCommand.h
@@ -31,7 +31,8 @@ private:
 protected:
     bool executeInternal(Segment segment);
 public:
-  FtpTunnelResponseCommand(int cuid, Request* req, DownloadEngine* e, const Socket* s);
+  FtpTunnelResponseCommand(int cuid, Request* req, DownloadEngine* e,
+			   const SocketHandle& s);
   ~FtpTunnelResponseCommand();
 };
 
diff --git a/src/HttpConnection.cc b/src/HttpConnection.cc
index d48b53f5..e63000a2 100644
--- a/src/HttpConnection.cc
+++ b/src/HttpConnection.cc
@@ -27,7 +27,8 @@
 #include "prefs.h"
 #include "LogFactory.h"
 
-HttpConnection::HttpConnection(int cuid, const Socket* socket, const Request* req, const Option* op):
+HttpConnection::HttpConnection(int cuid, const SocketHandle& socket,
+			       const Request* req, const Option* op):
   cuid(cuid), socket(socket), req(req), option(op), headerBufLength(0) {
   logger = LogFactory::getInstance();
 }
diff --git a/src/HttpConnection.h b/src/HttpConnection.h
index d340bbcc..7207aa1f 100644
--- a/src/HttpConnection.h
+++ b/src/HttpConnection.h
@@ -46,14 +46,15 @@ private:
   bool useProxyGet() const;
   string getProxyAuthString() const;
   int cuid;
-  const Socket* socket;
+  SocketHandle socket;
   const Request* req;
   const Option* option;
   const Logger* logger;
   char headerBuf[HEADERBUF_SIZE+1];
   int headerBufLength;
 public:
-  HttpConnection(int cuid, const Socket* socket, const Request* req, const Option* op);
+  HttpConnection(int cuid, const SocketHandle& socket, const Request* req,
+		 const Option* op);
 
   /**
    * Sends Http request.
diff --git a/src/HttpDownloadCommand.cc b/src/HttpDownloadCommand.cc
index 551f1a12..3077ab16 100644
--- a/src/HttpDownloadCommand.cc
+++ b/src/HttpDownloadCommand.cc
@@ -33,8 +33,8 @@ using namespace std;
 
 HttpDownloadCommand::HttpDownloadCommand(int cuid, Request* req,
 					 DownloadEngine* e,
-					 const Socket* socket):
-  DownloadCommand(cuid, req, e, socket)
+					 const SocketHandle& socket)
+  :DownloadCommand(cuid, req, e, socket)
 {
   ChunkedEncoding* ce = new ChunkedEncoding();
   transferEncodings["chunked"] = ce;
diff --git a/src/HttpDownloadCommand.h b/src/HttpDownloadCommand.h
index d81da732..440fa9ec 100644
--- a/src/HttpDownloadCommand.h
+++ b/src/HttpDownloadCommand.h
@@ -37,7 +37,8 @@ class HttpDownloadCommand:public DownloadCommand {
 private:
   map<string, TransferEncoding*> transferEncodings;
 public:
-  HttpDownloadCommand(int cuid, Request* req, DownloadEngine* e, const Socket* s);
+  HttpDownloadCommand(int cuid, Request* req, DownloadEngine* e,
+		      const SocketHandle& s);
   ~HttpDownloadCommand();
 
   TransferEncoding* getTransferEncoding(const string& transferEncoding);
diff --git a/src/HttpInitiateConnectionCommand.cc b/src/HttpInitiateConnectionCommand.cc
index 7bc29f96..73657192 100644
--- a/src/HttpInitiateConnectionCommand.cc
+++ b/src/HttpInitiateConnectionCommand.cc
@@ -27,12 +27,13 @@
 #include "message.h"
 #include "prefs.h"
 
-HttpInitiateConnectionCommand::HttpInitiateConnectionCommand(int cuid, Request* req, DownloadEngine* e):AbstractCommand(cuid, req, e) {}
+HttpInitiateConnectionCommand::HttpInitiateConnectionCommand(int cuid,
+							     Request* req,
+							     DownloadEngine* e):AbstractCommand(cuid, req, e) {}
 
 HttpInitiateConnectionCommand::~HttpInitiateConnectionCommand() {}
 
 bool HttpInitiateConnectionCommand::executeInternal(Segment segment) {
-  socket = new Socket();
   // socket->establishConnection(...);
   Command* command;
   if(useProxy()) {
diff --git a/src/HttpProxyRequestCommand.cc b/src/HttpProxyRequestCommand.cc
index 60b7fa89..0bf66558 100644
--- a/src/HttpProxyRequestCommand.cc
+++ b/src/HttpProxyRequestCommand.cc
@@ -23,8 +23,11 @@
 #include "HttpConnection.h"
 #include "HttpProxyResponseCommand.h"
 
-HttpProxyRequestCommand::HttpProxyRequestCommand(int cuid, Request* req, DownloadEngine* e, const Socket* s):AbstractCommand(cuid, req, e, s) {
-  setReadCheckSocket(NULL);
+HttpProxyRequestCommand::HttpProxyRequestCommand(int cuid, Request* req,
+						 DownloadEngine* e,
+						 const SocketHandle& s)
+  :AbstractCommand(cuid, req, e, s) {
+  disableReadCheckSocket();
   setWriteCheckSocket(socket);
 }
 
diff --git a/src/HttpProxyRequestCommand.h b/src/HttpProxyRequestCommand.h
index 6317faa0..2b5a646a 100644
--- a/src/HttpProxyRequestCommand.h
+++ b/src/HttpProxyRequestCommand.h
@@ -28,7 +28,8 @@ class HttpProxyRequestCommand : public AbstractCommand {
 protected:
   bool executeInternal(Segment segment);
 public:
-  HttpProxyRequestCommand(int cuid, Request* req, DownloadEngine* e, const Socket* s);
+  HttpProxyRequestCommand(int cuid, Request* req, DownloadEngine* e,
+			  const SocketHandle& s);
   ~HttpProxyRequestCommand();
 };
 
diff --git a/src/HttpProxyResponseCommand.cc b/src/HttpProxyResponseCommand.cc
index bfcb4496..51cb6580 100644
--- a/src/HttpProxyResponseCommand.cc
+++ b/src/HttpProxyResponseCommand.cc
@@ -24,7 +24,10 @@
 #include "DlRetryEx.h"
 #include "message.h"
 
-HttpProxyResponseCommand::HttpProxyResponseCommand(int cuid, Request* req, DownloadEngine* e, const Socket* s):AbstractCommand(cuid, req, e, s) {
+HttpProxyResponseCommand::HttpProxyResponseCommand(int cuid, Request* req,
+						   DownloadEngine* e,
+						   const SocketHandle& s)
+  :AbstractCommand(cuid, req, e, s) {
   http = new HttpConnection(cuid, socket, req, e->option);
 }
 
diff --git a/src/HttpProxyResponseCommand.h b/src/HttpProxyResponseCommand.h
index f9f7c4bf..ad938cf0 100644
--- a/src/HttpProxyResponseCommand.h
+++ b/src/HttpProxyResponseCommand.h
@@ -31,7 +31,8 @@ private:
 protected:
   bool executeInternal(Segment segment);
 public:
-  HttpProxyResponseCommand(int cuid, Request* req, DownloadEngine* e, const Socket* s);
+  HttpProxyResponseCommand(int cuid, Request* req, DownloadEngine* e,
+			   const SocketHandle& s);
   ~HttpProxyResponseCommand();
 };
 
diff --git a/src/HttpRequestCommand.cc b/src/HttpRequestCommand.cc
index 2a5e75a5..9f5ba45a 100644
--- a/src/HttpRequestCommand.cc
+++ b/src/HttpRequestCommand.cc
@@ -23,8 +23,11 @@
 #include "HttpResponseCommand.h"
 #include "HttpConnection.h"
 
-HttpRequestCommand::HttpRequestCommand(int cuid, Request* req, DownloadEngine* e, const Socket* s):AbstractCommand(cuid, req, e, s) {
-  setReadCheckSocket(NULL);
+HttpRequestCommand::HttpRequestCommand(int cuid, Request* req,
+				       DownloadEngine* e,
+				       const SocketHandle& s)
+  :AbstractCommand(cuid, req, e, s) {
+  disableReadCheckSocket();
   setWriteCheckSocket(socket);
 }
 
diff --git a/src/HttpRequestCommand.h b/src/HttpRequestCommand.h
index d224c5c3..d3fa923b 100644
--- a/src/HttpRequestCommand.h
+++ b/src/HttpRequestCommand.h
@@ -29,7 +29,8 @@ protected:
   bool executeInternal(Segment segment);
   Command* getNextCommand() const;
 public:
-  HttpRequestCommand(int cuid, Request* req, DownloadEngine* e, const Socket* s);
+  HttpRequestCommand(int cuid, Request* req, DownloadEngine* e,
+		     const SocketHandle& s);
   ~HttpRequestCommand();
 };
 
diff --git a/src/HttpResponseCommand.cc b/src/HttpResponseCommand.cc
index 97670683..d9f16977 100644
--- a/src/HttpResponseCommand.cc
+++ b/src/HttpResponseCommand.cc
@@ -29,8 +29,10 @@
 #include <sys/types.h>
 #include <unistd.h>
 
-HttpResponseCommand::HttpResponseCommand(int cuid, Request* req, DownloadEngine* e, const Socket* s):
-  AbstractCommand(cuid, req, e, s) {
+HttpResponseCommand::HttpResponseCommand(int cuid, Request* req,
+					 DownloadEngine* e,
+					 const SocketHandle& s)
+  :AbstractCommand(cuid, req, e, s) {
   http = new HttpConnection(cuid, socket, req, e->option);
 }
 
@@ -154,7 +156,6 @@ bool HttpResponseCommand::handleOtherEncoding(const string& transferEncoding, co
 }
 
 void HttpResponseCommand::createHttpDownloadCommand(const string& transferEncoding) {
-  
   HttpDownloadCommand* command = new HttpDownloadCommand(cuid, req, e, socket);
   TransferEncoding* enc = NULL;
   if(transferEncoding.size() && (enc = command->getTransferEncoding(transferEncoding)) == NULL) {
diff --git a/src/HttpResponseCommand.h b/src/HttpResponseCommand.h
index bdf192ee..19a092c4 100644
--- a/src/HttpResponseCommand.h
+++ b/src/HttpResponseCommand.h
@@ -38,7 +38,8 @@ private:
 protected:
   bool executeInternal(Segment segment);
 public:
-  HttpResponseCommand(int cuid, Request* req, DownloadEngine* e, const Socket* s);
+  HttpResponseCommand(int cuid, Request* req, DownloadEngine* e,
+		      const SocketHandle& s);
   ~HttpResponseCommand();
 };
 
diff --git a/src/InitiateConnectionCommandFactory.cc b/src/InitiateConnectionCommandFactory.cc
index 8af1532d..7f6e75f7 100644
--- a/src/InitiateConnectionCommandFactory.cc
+++ b/src/InitiateConnectionCommandFactory.cc
@@ -22,6 +22,7 @@
 #include "InitiateConnectionCommandFactory.h"
 #include "HttpInitiateConnectionCommand.h"
 #include "FtpInitiateConnectionCommand.h"
+#include "DlAbortEx.h"
 
 Command* InitiateConnectionCommandFactory::createInitiateConnectionCommand(int cuid, Request* req, DownloadEngine* e) {
   if(req->getProtocol() == "http"
@@ -35,6 +36,6 @@ Command* InitiateConnectionCommandFactory::createInitiateConnectionCommand(int c
     return new FtpInitiateConnectionCommand(cuid, req, e);
   } else {
     // these protocols are not supported yet
-    return NULL;
+    throw new DlAbortEx("%s is not supported yet.", req->getProtocol().c_str());
   }
 }
diff --git a/src/InitiateConnectionCommandFactory.h b/src/InitiateConnectionCommandFactory.h
index dea10ed4..57cfe1be 100644
--- a/src/InitiateConnectionCommandFactory.h
+++ b/src/InitiateConnectionCommandFactory.h
@@ -28,7 +28,8 @@
 
 class InitiateConnectionCommandFactory {
 public:
-  static Command* createInitiateConnectionCommand(int cuid, Request* req, DownloadEngine* e);
+  static Command* createInitiateConnectionCommand(int cuid, Request* req, 
+						  DownloadEngine* e);
 };
 
 #endif // _D_INITIATE_CONNECTION_COMMAND_FACTORY_H_
diff --git a/src/Makefile.am b/src/Makefile.am
index 3b16130b..f80591b9 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1,8 +1,8 @@
 bin_PROGRAMS = aria2c
 aria2c_SOURCES = main.cc
-SRCS =  Socket.cc Socket.h\
+SRCS =  Socket.h\
 	SocketCore.cc SocketCore.h\
-	Command.h\
+	Command.cc Command.h\
 	AbstractCommand.cc AbstractCommand.h\
 	InitiateConnectionCommandFactory.cc InitiateConnectionCommandFactory.h\
 	DownloadCommand.cc DownloadCommand.h\
@@ -104,7 +104,8 @@ SRCS += MetaEntry.h\
 	RejectMessage.cc RejectMessage.h\
 	AllowedFastMessage.cc AllowedFastMessage.h\
 	SuggestPieceMessage.cc SuggestPieceMessage.h\
-	SimplePeerMessage.cc SimplePeerMessage.h
+	SimplePeerMessage.cc SimplePeerMessage.h\
+	SharedHandle.h
 endif # ENABLE_BITTORRENT
 
 if ENABLE_METALINK
diff --git a/src/Makefile.in b/src/Makefile.in
index 8cffb7f3..678a8f85 100644
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -89,7 +89,8 @@ bin_PROGRAMS = aria2c$(EXEEXT)
 @ENABLE_BITTORRENT_TRUE@	RejectMessage.cc RejectMessage.h\
 @ENABLE_BITTORRENT_TRUE@	AllowedFastMessage.cc AllowedFastMessage.h\
 @ENABLE_BITTORRENT_TRUE@	SuggestPieceMessage.cc SuggestPieceMessage.h\
-@ENABLE_BITTORRENT_TRUE@	SimplePeerMessage.cc SimplePeerMessage.h
+@ENABLE_BITTORRENT_TRUE@	SimplePeerMessage.cc SimplePeerMessage.h\
+@ENABLE_BITTORRENT_TRUE@	SharedHandle.h
 
 @ENABLE_METALINK_TRUE@am__append_2 = Metalinker.cc Metalinker.h\
 @ENABLE_METALINK_TRUE@	MetalinkEntry.cc MetalinkEntry.h\
@@ -121,8 +122,8 @@ AR = ar
 ARFLAGS = cru
 libaria2c_a_AR = $(AR) $(ARFLAGS)
 libaria2c_a_LIBADD =
-am__libaria2c_a_SOURCES_DIST = Socket.cc Socket.h SocketCore.cc \
-	SocketCore.h Command.h AbstractCommand.cc AbstractCommand.h \
+am__libaria2c_a_SOURCES_DIST = Socket.h SocketCore.cc SocketCore.h \
+	Command.cc Command.h AbstractCommand.cc AbstractCommand.h \
 	InitiateConnectionCommandFactory.cc \
 	InitiateConnectionCommandFactory.h DownloadCommand.cc \
 	DownloadCommand.h HttpInitiateConnectionCommand.cc \
@@ -186,8 +187,8 @@ am__libaria2c_a_SOURCES_DIST = Socket.cc Socket.h SocketCore.cc \
 	HaveNoneMessage.cc HaveNoneMessage.h RejectMessage.cc \
 	RejectMessage.h AllowedFastMessage.cc AllowedFastMessage.h \
 	SuggestPieceMessage.cc SuggestPieceMessage.h \
-	SimplePeerMessage.cc SimplePeerMessage.h Metalinker.cc \
-	Metalinker.h MetalinkEntry.cc MetalinkEntry.h \
+	SimplePeerMessage.cc SimplePeerMessage.h SharedHandle.h \
+	Metalinker.cc Metalinker.h MetalinkEntry.cc MetalinkEntry.h \
 	MetalinkResource.cc MetalinkResource.h MetalinkProcessor.h \
 	Xml2MetalinkProcessor.cc Xml2MetalinkProcessor.h
 @ENABLE_BITTORRENT_TRUE@am__objects_1 = Data.$(OBJEXT) \
@@ -240,7 +241,7 @@ am__libaria2c_a_SOURCES_DIST = Socket.cc Socket.h SocketCore.cc \
 @ENABLE_METALINK_TRUE@	MetalinkEntry.$(OBJEXT) \
 @ENABLE_METALINK_TRUE@	MetalinkResource.$(OBJEXT) \
 @ENABLE_METALINK_TRUE@	Xml2MetalinkProcessor.$(OBJEXT)
-am__objects_3 = Socket.$(OBJEXT) SocketCore.$(OBJEXT) \
+am__objects_3 = SocketCore.$(OBJEXT) Command.$(OBJEXT) \
 	AbstractCommand.$(OBJEXT) \
 	InitiateConnectionCommandFactory.$(OBJEXT) \
 	DownloadCommand.$(OBJEXT) \
@@ -420,7 +421,7 @@ sharedstatedir = @sharedstatedir@
 sysconfdir = @sysconfdir@
 target_alias = @target_alias@
 aria2c_SOURCES = main.cc
-SRCS = Socket.cc Socket.h SocketCore.cc SocketCore.h Command.h \
+SRCS = Socket.h SocketCore.cc SocketCore.h Command.cc Command.h \
 	AbstractCommand.cc AbstractCommand.h \
 	InitiateConnectionCommandFactory.cc \
 	InitiateConnectionCommandFactory.h DownloadCommand.cc \
@@ -547,6 +548,7 @@ distclean-compile:
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/CancelMessage.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/ChokeMessage.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/ChunkedEncoding.Po@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/Command.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/ConsoleDownloadEngine.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/CookieBox.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/CopyDiskAdaptor.Po@am__quote@
@@ -614,7 +616,6 @@ distclean-compile:
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/SimpleLogger.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/SimplePeerMessage.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/SleepCommand.Po@am__quote@
-@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/Socket.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/SocketCore.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/SplitFirstSegmentSplitter.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/SplitSlowestSegmentSplitter.Po@am__quote@
diff --git a/src/Peer.cc b/src/Peer.cc
index 7df0d081..019f9a06 100644
--- a/src/Peer.cc
+++ b/src/Peer.cc
@@ -21,7 +21,7 @@
 /* copyright --> */
 #include "Peer.h"
 
-Peer* Peer::nullPeer = new Peer("", 0, 0, 0);
+PeerHandle nullPeer = PeerHandle(new Peer("", 0, 0, 0));
 
 void Peer::updateBitfield(int index, int operation) {
   if(operation == 1) {
@@ -82,3 +82,11 @@ void Peer::setAllBitfield() {
 void Peer::updateLatency(int latency) {
   this->latency = (this->latency*20+latency*80)/200;
 }
+
+bool operator==(const Peer& p1, const Peer& p2) {
+  return p1.ipaddr == p2.ipaddr && p1.port == p2.port;
+}
+
+bool operator!=(const Peer& p1, const Peer& p2) {
+  return !(p1 == p2);
+}
diff --git a/src/Peer.h b/src/Peer.h
index 5bc8a27a..d37e6aad 100644
--- a/src/Peer.h
+++ b/src/Peer.h
@@ -24,6 +24,7 @@
 
 #include "common.h"
 #include "BitfieldMan.h"
+#include "SharedHandle.h"
 #include <string.h>
 #include <string>
 
@@ -33,6 +34,8 @@ using namespace std;
 #define DEFAULT_LATENCY 1500
 
 class Peer {
+  friend bool operator==(const Peer& p1, const Peer& p2);
+  friend bool operator!=(const Peer& p1, const Peer& p2);
 public:
   int entryId;
   string ipaddr;
@@ -60,22 +63,20 @@ private:
   int deltaDownload;
   int latency;
 public:
-  Peer(string ipaddr, int port, int pieceLength, long long int totalLength):
-    entryId(0), ipaddr(ipaddr), port(port),
-    amChoking(true), amInterested(false),
-    peerChoking(true), peerInterested(false),
-    tryCount(0), error(0), cuid(0),
-    chokingRequired(true), optUnchoking(false),
-    snubbing(false),
-    bitfield(NULL),
-    fastExtensionEnabled(false),
-    peerUpload(0), peerDownload(0),
-    pieceLength(pieceLength),
-    deltaUpload(0), deltaDownload(0),
-    latency(DEFAULT_LATENCY) {
+  Peer(string ipaddr, int port, int pieceLength, long long int totalLength)
+    :entryId(0), ipaddr(ipaddr), port(port), error(0),
+     peerUpload(0), peerDownload(0), pieceLength(pieceLength)
+  {
+    resetStatus();
     this->bitfield = new BitfieldMan(pieceLength, totalLength);
   }
 
+  Peer():entryId(0), ipaddr(""), port(0), bitfield(0),
+	 peerUpload(0), peerDownload(0), pieceLength(0)
+  {
+    resetStatus();
+  }
+
   ~Peer() {
     if(bitfield != NULL) {
       delete bitfield;
@@ -146,8 +147,11 @@ public:
 
   void updateLatency(int latency);
   int getLatency() const { return latency; }
-
-  static Peer* nullPeer;
 };
 
+bool operator==(const Peer& p1, const Peer& p2);
+bool operator!=(const Peer& p1, const Peer& p2);
+
+typedef SharedHandle<Peer> PeerHandle;
+
 #endif // _D_PEER_H_
diff --git a/src/PeerAbstractCommand.cc b/src/PeerAbstractCommand.cc
index 651c865f..b53e8ca0 100644
--- a/src/PeerAbstractCommand.cc
+++ b/src/PeerAbstractCommand.cc
@@ -26,27 +26,20 @@
 #include "message.h"
 #include "prefs.h"
 
-PeerAbstractCommand::PeerAbstractCommand(int cuid, Peer* peer, TorrentDownloadEngine* e, const Socket* s):
-  Command(cuid), e(e), peer(peer),
+PeerAbstractCommand::PeerAbstractCommand(int cuid, const PeerHandle& peer,
+					 TorrentDownloadEngine* e,
+					 const SocketHandle& s)
+  :Command(cuid), e(e), socket(s), peer(peer),
   checkSocketIsReadable(false), checkSocketIsWritable(false),
   uploadLimitCheck(false), uploadLimit(0) {
-
-  if(s != NULL) {
-    socket = new Socket(*s);
-    setReadCheckSocket(socket);
-  } else {
-    socket = NULL;
-  }
+  setReadCheckSocket(socket);
   timeout = e->option->getAsInt(PREF_TIMEOUT);
   e->torrentMan->connections++;
 }
 
 PeerAbstractCommand::~PeerAbstractCommand() {
-  setReadCheckSocket(NULL);
-  setWriteCheckSocket(NULL);
-  if(socket != NULL) {
-    delete(socket);
-  }
+  disableReadCheckSocket();
+  disableWriteCheckSocket();
   e->torrentMan->connections--;
 }
 
@@ -92,44 +85,52 @@ void PeerAbstractCommand::onAbort(Exception* ex) {
   logger->debug("CUID#%d - Peer %s:%d banned.", cuid, peer->ipaddr.c_str(), peer->port);
 }
 
-void PeerAbstractCommand::setReadCheckSocket(Socket* socket) {
-  if(socket == NULL) {
-    if(checkSocketIsReadable) {
-      e->deleteSocketForReadCheck(readCheckTarget);
-      checkSocketIsReadable = false;
-      readCheckTarget = NULL;
-    }
+void PeerAbstractCommand::disableReadCheckSocket() {
+  if(checkSocketIsReadable) {
+    e->deleteSocketForReadCheck(readCheckTarget, getUuid());
+    checkSocketIsReadable = false;
+    readCheckTarget = SocketHandle();
+  }  
+}
+
+void PeerAbstractCommand::setReadCheckSocket(const SocketHandle& socket) {
+  if(!socket->isOpen()) {
+    disableReadCheckSocket();
   } else {
     if(checkSocketIsReadable) {
       if(readCheckTarget != socket) {
-	e->deleteSocketForReadCheck(readCheckTarget);
-	e->addSocketForReadCheck(socket, this);
+	e->deleteSocketForReadCheck(readCheckTarget, getUuid());
+	e->addSocketForReadCheck(socket, getUuid());
 	readCheckTarget = socket;
       }
     } else {
-      e->addSocketForReadCheck(socket, this);
+      e->addSocketForReadCheck(socket, getUuid());
       checkSocketIsReadable = true;
       readCheckTarget = socket;
     }
   }
 }
 
-void PeerAbstractCommand::setWriteCheckSocket(Socket* socket) {
-  if(socket == NULL) {
-    if(checkSocketIsWritable) {
-      e->deleteSocketForWriteCheck(writeCheckTarget);
-      checkSocketIsWritable = false;
-      writeCheckTarget = NULL;
-    }
+void PeerAbstractCommand::disableWriteCheckSocket() {
+  if(checkSocketIsWritable) {
+    e->deleteSocketForWriteCheck(writeCheckTarget, getUuid());
+    checkSocketIsWritable = false;
+    writeCheckTarget = SocketHandle();
+  }
+}
+
+void PeerAbstractCommand::setWriteCheckSocket(const SocketHandle& socket) {
+  if(!socket->isOpen()) {
+    disableWriteCheckSocket();
   } else {
     if(checkSocketIsWritable) {
       if(writeCheckTarget != socket) {
-	e->deleteSocketForWriteCheck(writeCheckTarget);
-	e->addSocketForWriteCheck(socket, this);
+	e->deleteSocketForWriteCheck(writeCheckTarget, getUuid());
+	e->addSocketForWriteCheck(socket, getUuid());
 	writeCheckTarget = socket;
       }
     } else {
-      e->addSocketForWriteCheck(socket, this);
+      e->addSocketForWriteCheck(socket, getUuid());
       checkSocketIsWritable = true;
       writeCheckTarget = socket;
     }
diff --git a/src/PeerAbstractCommand.h b/src/PeerAbstractCommand.h
index 2458d31e..4f240492 100644
--- a/src/PeerAbstractCommand.h
+++ b/src/PeerAbstractCommand.h
@@ -33,26 +33,30 @@ private:
   int timeout;
 protected:
   TorrentDownloadEngine* e;
-  Socket* socket;
-  Peer* peer;
+  SocketHandle socket;
+  PeerHandle peer;
   void setTimeout(int timeout) { this->timeout = timeout; }
   virtual bool prepareForNextPeer(int wait);
   virtual bool prepareForRetry(int wait);
   virtual void onAbort(Exception* ex);
   virtual bool executeInternal() = 0;
-  void setReadCheckSocket(Socket* socket);
-  void setWriteCheckSocket(Socket* socket);
+  void setReadCheckSocket(const SocketHandle& socket);
+  void setWriteCheckSocket(const SocketHandle& socket);
+  void disableReadCheckSocket();
+  void disableWriteCheckSocket();
   void setUploadLimit(int uploadLimit);
   void setUploadLimitCheck(bool check);
 private:
   bool checkSocketIsReadable;
   bool checkSocketIsWritable;
-  Socket* readCheckTarget;
-  Socket* writeCheckTarget;
+  SocketHandle readCheckTarget;
+  SocketHandle writeCheckTarget;
   bool uploadLimitCheck;
   int uploadLimit;
 public:
-  PeerAbstractCommand(int cuid, Peer* peer, TorrentDownloadEngine* e, const Socket* s = NULL);
+  PeerAbstractCommand(int cuid, const PeerHandle& peer,
+		      TorrentDownloadEngine* e,
+		      const SocketHandle& s = SocketHandle());
   virtual ~PeerAbstractCommand();
   bool execute();
 };
diff --git a/src/PeerChokeCommand.cc b/src/PeerChokeCommand.cc
index 04fb481c..7a32e6da 100644
--- a/src/PeerChokeCommand.cc
+++ b/src/PeerChokeCommand.cc
@@ -26,12 +26,13 @@ PeerChokeCommand::PeerChokeCommand(int cuid, int interval, TorrentDownloadEngine
 
 PeerChokeCommand::~PeerChokeCommand() {}
 
-void PeerChokeCommand::setAllPeerChoked(Peers& peers) const {
-  for(Peers::iterator itr = peers.begin(); itr != peers.end(); itr++) {
-    Peer* peer = *itr;
+class ChokePeer {
+public:
+  ChokePeer() {}
+  void operator()(PeerHandle& peer) {
     peer->chokingRequired = true;
   }
-}
+};
 
 void PeerChokeCommand::optUnchokingPeer(Peers& peers) const {
   if(peers.empty()) {
@@ -52,17 +53,18 @@ void PeerChokeCommand::optUnchokingPeer(Peers& peers) const {
   }
 }
 
-void PeerChokeCommand::setAllPeerResetDelta(Peers& peers) const {
-  for(Peers::iterator itr = peers.begin(); itr != peers.end(); itr++) {
-    Peer* peer = *itr;
+class ResetDelta {
+public:
+  ResetDelta() {}
+  void operator()(PeerHandle& peer) {
     peer->resetDeltaUpload();
     peer->resetDeltaDownload();
   }
-}
+};
 
 class UploadFaster {
 public:
-  bool operator() (const Peer* left, const Peer* right) const {
+  bool operator() (const PeerHandle& left, const PeerHandle& right) const {
     return left->getDeltaUpload() > right->getDeltaUpload();
   }
 };
@@ -73,13 +75,13 @@ void PeerChokeCommand::orderByUploadRate(Peers& peers) const {
 
 class DownloadFaster {
 public:
-  bool operator() (const Peer* left, const Peer* right) const {
+  bool operator() (const PeerHandle& left, const PeerHandle& right) const {
     return left->getDeltaDownload() > right->getDeltaDownload();
   }
 };
 
 void PeerChokeCommand::orderByDownloadRate(Peers& peers) const {
-  sort(peers.begin(), peers.end(), UploadFaster());
+  sort(peers.begin(), peers.end(), DownloadFaster());
 }
 
 bool PeerChokeCommand::execute() {
@@ -89,7 +91,7 @@ bool PeerChokeCommand::execute() {
   if(checkPoint.elapsed(interval)) {
     checkPoint.reset();
     Peers peers = e->torrentMan->getActivePeers();
-    setAllPeerChoked(peers);
+    for_each(peers.begin(), peers.end(), ChokePeer());
     if(e->torrentMan->downloadComplete()) {
       orderByDownloadRate(peers);
     } else {
@@ -97,24 +99,30 @@ bool PeerChokeCommand::execute() {
     }
     int unchokingCount = 4;//peers.size() >= 4 ? 4 : peers.size();
     for(Peers::iterator itr = peers.begin(); itr != peers.end() && unchokingCount > 0; ) {
-      Peer* peer = *itr;
+      PeerHandle peer = *itr;
       if(peer->peerInterested && !peer->snubbing) {
 	unchokingCount--;
 	peer->chokingRequired = false;
 	peer->optUnchoking = false;
 	itr = peers.erase(itr);
-	logger->debug("cat01, unchoking %s, delta=%d", peer->ipaddr.c_str(), peer->getDeltaUpload());
+	logger->debug("cat01, unchoking %s, delta=%d",
+		      peer->ipaddr.c_str(),
+		      e->torrentMan->downloadComplete() ?
+		      peer->getDeltaDownload() : peer->getDeltaUpload());
       } else {
 	itr++;
       }
     }
     for(Peers::iterator itr = peers.begin(); itr != peers.end(); ) {
-      Peer* peer = *itr;
+      PeerHandle peer = *itr;
       if(!peer->peerInterested && !peer->snubbing) {
 	peer->chokingRequired = false;
 	peer->optUnchoking = false;
 	itr = peers.erase(itr);
-	logger->debug("cat02, unchoking %s, delta=%d", peer->ipaddr.c_str(), peer->getDeltaUpload());
+	logger->debug("cat02, unchoking %s, delta=%d",
+		      peer->ipaddr.c_str(),
+		      e->torrentMan->downloadComplete() ?
+		      peer->getDeltaDownload() : peer->getDeltaUpload());
 	break;
       } else {
 	itr++;
@@ -125,7 +133,9 @@ bool PeerChokeCommand::execute() {
       rotate = 0;
     }
     rotate++;
-    setAllPeerResetDelta(e->torrentMan->getActivePeers());
+    for_each(e->torrentMan->getActivePeers().begin(),
+	     e->torrentMan->getActivePeers().end(),
+	     ResetDelta());
   }
   e->commands.push_back(this);
   return false;
diff --git a/src/PeerChokeCommand.h b/src/PeerChokeCommand.h
index 16fdd701..c0019bf6 100644
--- a/src/PeerChokeCommand.h
+++ b/src/PeerChokeCommand.h
@@ -35,8 +35,6 @@ private:
 
   void orderByUploadRate(Peers& peers) const;
   void orderByDownloadRate(Peers& peers) const;
-  void setAllPeerChoked(Peers& peers) const;
-  void setAllPeerResetDelta(Peers& peers) const;
   void optUnchokingPeer(Peers& peers) const;
 
 public:
diff --git a/src/PeerConnection.cc b/src/PeerConnection.cc
index aa3149e9..104e65d6 100644
--- a/src/PeerConnection.cc
+++ b/src/PeerConnection.cc
@@ -28,7 +28,7 @@
 #include <netinet/in.h>
 
 PeerConnection::PeerConnection(int cuid,
-			       const Socket* socket,
+			       const SocketHandle& socket,
 			       const Option* op)
   :cuid(cuid),
    socket(socket),
diff --git a/src/PeerConnection.h b/src/PeerConnection.h
index e96f37e9..f7c238a4 100644
--- a/src/PeerConnection.h
+++ b/src/PeerConnection.h
@@ -27,7 +27,6 @@
 #include "Logger.h"
 #include "TorrentMan.h"
 #include "PeerMessage.h"
-#include "HandshakeMessage.h"
 #include "common.h"
 
 // we assume maximum length of incoming message is "piece" message with 16KB
@@ -37,7 +36,7 @@
 class PeerConnection {
 private:
   int cuid;
-  const Socket* socket;
+  SocketHandle socket;
   const Option* option;
   const Logger* logger;
 
@@ -48,7 +47,7 @@ private:
   int lenbufLength;
 
 public:
-  PeerConnection(int cuid, const Socket* socket, const Option* op);
+  PeerConnection(int cuid, const SocketHandle& socket, const Option* op);
   ~PeerConnection();
   
   // Returns the number of bytes written
diff --git a/src/PeerInitiateConnectionCommand.cc b/src/PeerInitiateConnectionCommand.cc
index cea9a12b..59056227 100644
--- a/src/PeerInitiateConnectionCommand.cc
+++ b/src/PeerInitiateConnectionCommand.cc
@@ -27,16 +27,13 @@
 #include "prefs.h"
 
 PeerInitiateConnectionCommand::PeerInitiateConnectionCommand(int cuid,
-							     Peer* peer,
+							     const PeerHandle& peer,
 							     TorrentDownloadEngine* e)
   :PeerAbstractCommand(cuid, peer, e) {}
 
 PeerInitiateConnectionCommand::~PeerInitiateConnectionCommand() {}
 
 bool PeerInitiateConnectionCommand::executeInternal() {
-  socket = new Socket();
-  // socket->establishConnection(...);
-
   Command* command;
   logger->info(MSG_CONNECTING_TO_SERVER, cuid, peer->ipaddr.c_str(),
 	       peer->port);
@@ -50,10 +47,11 @@ bool PeerInitiateConnectionCommand::executeInternal() {
 // TODO this method removed when PeerBalancerCommand is implemented
 bool PeerInitiateConnectionCommand::prepareForNextPeer(int wait) {
   if(e->torrentMan->isPeerAvailable()) {
-    Peer* peer = e->torrentMan->getPeer();
+    PeerHandle peer = e->torrentMan->getPeer();
     int newCuid = e->torrentMan->getNewCuid();
     peer->cuid = newCuid;
-    PeerInitiateConnectionCommand* command = new PeerInitiateConnectionCommand(newCuid, peer, e);
+    PeerInitiateConnectionCommand* command =
+      new PeerInitiateConnectionCommand(newCuid, peer, e);
     e->commands.push_back(command);
   }
   return true;
diff --git a/src/PeerInitiateConnectionCommand.h b/src/PeerInitiateConnectionCommand.h
index b6599544..66313b95 100644
--- a/src/PeerInitiateConnectionCommand.h
+++ b/src/PeerInitiateConnectionCommand.h
@@ -30,7 +30,8 @@ protected:
   bool prepareForRetry(int wait);
   bool prepareForNextPeer(int wait);
 public:
-  PeerInitiateConnectionCommand(int cuid,  Peer* peer, TorrentDownloadEngine* e);
+  PeerInitiateConnectionCommand(int cuid,  const PeerHandle& peer,
+				TorrentDownloadEngine* e);
   ~PeerInitiateConnectionCommand();
 };
 
diff --git a/src/PeerInteraction.cc b/src/PeerInteraction.cc
index d3c4ebde..8ef87146 100644
--- a/src/PeerInteraction.cc
+++ b/src/PeerInteraction.cc
@@ -28,10 +28,10 @@
 #include <netinet/in.h>
 
 PeerInteraction::PeerInteraction(int cuid,
-				 const Socket* socket,
+				 const PeerHandle& peer,
+				 const SocketHandle& socket,
 				 const Option* op,
-				 TorrentMan* torrentMan,
-				 Peer* peer)
+				 TorrentMan* torrentMan)
   :cuid(cuid),
    uploadLimit(0),
    torrentMan(torrentMan),
@@ -43,7 +43,6 @@ PeerInteraction::PeerInteraction(int cuid,
 
 PeerInteraction::~PeerInteraction() {
   delete peerConnection;
-  for_each(messageQueue.begin(), messageQueue.end(), Deleter());
 }
 
 class MsgPushBack {
@@ -52,14 +51,14 @@ private:
 public:
   MsgPushBack(MessageQueue* messageQueue):messageQueue(messageQueue) {}
 
-  void operator()(PeerMessage* msg) {
+  void operator()(const PeerMessageHandle& msg) {
     messageQueue->push_back(msg);
   }
 };
 
 bool PeerInteraction::isSendingMessageInProgress() const {
   if(messageQueue.size() > 0) {
-    PeerMessage* peerMessage = messageQueue.front();
+    const PeerMessageHandle& peerMessage = messageQueue.front();
     if(peerMessage->isInProgress()) {
       return true;
     }
@@ -70,7 +69,7 @@ bool PeerInteraction::isSendingMessageInProgress() const {
 void PeerInteraction::sendMessages(int uploadSpeed) {
   MessageQueue tempQueue;
   while(messageQueue.size() > 0) {
-    PeerMessage* msg = messageQueue.front();
+    PeerMessageHandle msg = messageQueue.front();
     messageQueue.pop_front();
     if(uploadLimit != 0 && uploadLimit*1024 <= uploadSpeed &&
        msg->getId() == PieceMessage::ID && !msg->isInProgress()) {
@@ -78,27 +77,20 @@ void PeerInteraction::sendMessages(int uploadSpeed) {
       //((PieceMessage*)msg)->incrementPendingCount();
       tempQueue.push_back(msg);
     } else {
-      try {
-	msg->send();
-      } catch(Exception* ex) {
-	delete msg;
-	throw;
-      }
+      msg->send();
       if(msg->isInProgress()) {
 	messageQueue.push_front(msg);
 	break;
-      } else {
-	delete msg;
       }
     }
   }
   for_each(tempQueue.begin(), tempQueue.end(), MsgPushBack(&messageQueue));
 }
 
-void PeerInteraction::addMessage(PeerMessage* peerMessage) {
+void PeerInteraction::addMessage(const PeerMessageHandle& peerMessage) {
   messageQueue.push_back(peerMessage);
   if(peerMessage->getId() == RequestMessage::ID) {
-    RequestMessage* requestMessage = (RequestMessage*)peerMessage;
+    RequestMessage* requestMessage = (RequestMessage*)peerMessage.get();
     RequestSlot requestSlot(requestMessage->getIndex(),
 			    requestMessage->getBegin(),
 			    requestMessage->getLength(),
@@ -113,8 +105,8 @@ void PeerInteraction::rejectAllPieceMessageInQueue() {
       itr != messageQueue.end();) {
     // Don't delete piece message which is in the allowed fast set.
     if((*itr)->getId() == PieceMessage::ID && !(*itr)->isInProgress()
-       && !isInFastSet(((PieceMessage*)*itr)->getIndex())) {
-      PieceMessage* pieceMessage = (PieceMessage*)*itr;
+       && !isInFastSet(((PieceMessage*)(*itr).get())->getIndex())) {
+      PieceMessage* pieceMessage = (PieceMessage*)(*itr).get();
       logger->debug("CUID#%d - Reject piece message in queue because"
 		    " peer has been choked. index=%d, begin=%d, length=%d",
 		    cuid,
@@ -126,7 +118,6 @@ void PeerInteraction::rejectAllPieceMessageInQueue() {
 						pieceMessage->getBegin(),
 						pieceMessage->getBlockLength()));
       }
-      delete pieceMessage;
       itr = messageQueue.erase(itr);
     } else {
       itr++;
@@ -140,14 +131,13 @@ void PeerInteraction::rejectPieceMessageInQueue(int index, int begin, int length
   for(MessageQueue::iterator itr = messageQueue.begin();
       itr != messageQueue.end();) {
     if((*itr)->getId() == PieceMessage::ID && !(*itr)->isInProgress()) {
-      PieceMessage* pieceMessage = (PieceMessage*)*itr;
+      PieceMessage* pieceMessage = (PieceMessage*)(*itr).get();
       if(pieceMessage->getIndex() == index &&
 	 pieceMessage->getBegin() == begin &&
 	 pieceMessage->getBlockLength() == length) {
 	logger->debug("CUID#%d - Reject piece message in queue because cancel"
 		      " message received. index=%d, begin=%d, length=%d",
 		      cuid, index, begin, length);
-	delete pieceMessage;
 	itr = messageQueue.erase(itr);
 	if(peer->isFastExtensionEnabled()) {
 	  tempQueue.push_back(createRejectMessage(index, begin, length));
@@ -187,8 +177,7 @@ void PeerInteraction::abortPiece(Piece& piece) {
 	itr != messageQueue.end();) {
       if((*itr)->getId() == RequestMessage::ID &&
 	!(*itr)->isInProgress() &&
-	 ((RequestMessage*)*itr)->getIndex() == piece.getIndex()) {
-	delete *itr;
+	 ((RequestMessage*)(*itr).get())->getIndex() == piece.getIndex()) {
 	itr = messageQueue.erase(itr);
       } else {
 	itr++;
@@ -286,7 +275,7 @@ int PeerInteraction::countRequestSlot() const {
   return requestSlots.size();
 }
 
-HandshakeMessage* PeerInteraction::receiveHandshake(bool quickReply) {
+HandshakeMessageHandle PeerInteraction::receiveHandshake(bool quickReply) {
   char msg[HANDSHAKE_MESSAGE_LENGTH];
   int msgLength = HANDSHAKE_MESSAGE_LENGTH;
   bool retval = peerConnection->receiveHandshake(msg, msgLength);
@@ -301,13 +290,8 @@ HandshakeMessage* PeerInteraction::receiveHandshake(bool quickReply) {
   if(!retval) {
     return NULL;
   }
-  HandshakeMessage* handshakeMessage = createHandshakeMessage(msg, msgLength);
-  try {
-    handshakeMessage->check();
-  } catch(Exception* e) {
-    delete handshakeMessage;
-    throw;
-  }
+  HandshakeMessageHandle handshakeMessage(createHandshakeMessage(msg, msgLength));
+  handshakeMessage->check();
   if(handshakeMessage->isFastExtensionSupported()) {
     peer->setFastExtensionEnabled(true);
     logger->info("CUID#%d - Fast extension enabled.", cuid);
@@ -315,30 +299,25 @@ HandshakeMessage* PeerInteraction::receiveHandshake(bool quickReply) {
   return handshakeMessage;
 }
 
-HandshakeMessage* PeerInteraction::createHandshakeMessage(const char* msg, int msgLength) {
+HandshakeMessageHandle PeerInteraction::createHandshakeMessage(const char* msg, int msgLength) {
   HandshakeMessage* message = HandshakeMessage::create(msg, msgLength);
 
   setPeerMessageCommonProperty(message);
   return message;
 }
 
-PeerMessage* PeerInteraction::receiveMessage() {
+PeerMessageHandle PeerInteraction::receiveMessage() {
   char msg[MAX_PAYLOAD_LEN];
   int msgLength = 0;
   if(!peerConnection->receiveMessage(msg, msgLength)) {
     return NULL;
   }
-  PeerMessage* peerMessage = createPeerMessage(msg, msgLength);
-  try {
-    peerMessage->check();
-  } catch(Exception* e) {
-    delete peerMessage;
-    throw;
-  }
+  PeerMessageHandle peerMessage(createPeerMessage(msg, msgLength));
+  peerMessage->check();
   return peerMessage;
 }
 
-PeerMessage* PeerInteraction::createPeerMessage(const char* msg, int msgLength) {
+PeerMessageHandle PeerInteraction::createPeerMessage(const char* msg, int msgLength) {
   PeerMessage* peerMessage;
   if(msgLength == 0) {
     // keep-alive
diff --git a/src/PeerInteraction.h b/src/PeerInteraction.h
index f3e9ff7d..e0c0f969 100644
--- a/src/PeerInteraction.h
+++ b/src/PeerInteraction.h
@@ -42,12 +42,15 @@
 #include "AllowedFastMessage.h"
 #include "SuggestPieceMessage.h"
 #include "RequestSlot.h"
+#include "SharedHandle.h"
 
 #define REQUEST_TIME_OUT 60
 #define ALLOWED_FAST_SET_SIZE 10
 
+typedef SharedHandle<PeerMessage> PeerMessageHandle;
+typedef SharedHandle<HandshakeMessage> HandshakeMessageHandle;
 typedef deque<RequestSlot> RequestSlots;
-typedef deque<PeerMessage*> MessageQueue;
+typedef deque<PeerMessageHandle> MessageQueue;
 
 class PeerInteraction {
 private:
@@ -58,7 +61,7 @@ private:
   int uploadLimit;
   TorrentMan* torrentMan;
   PeerConnection* peerConnection;
-  Peer* peer;
+  PeerHandle peer;
   Pieces pieces;
   // allowed fast piece indexes that local client has sent
   Integers fastSet;
@@ -66,19 +69,19 @@ private:
   const Logger* logger;
 
   void getNewPieceAndSendInterest(int pieceNum);
-  PeerMessage* createPeerMessage(const char* msg, int msgLength);
-  HandshakeMessage* createHandshakeMessage(const char* msg, int msgLength);
+  PeerMessageHandle createPeerMessage(const char* msg, int msgLength);
+  HandshakeMessageHandle createHandshakeMessage(const char* msg, int msgLength);
   void setPeerMessageCommonProperty(PeerMessage* peerMessage);
   int countRequestSlot() const;
 public:
   PeerInteraction(int cuid,
-		  const Socket* socket,
+		  const PeerHandle& peer,
+		  const SocketHandle& socket,
 		  const Option* op,
-		  TorrentMan* torrentMan,
-		  Peer* peer);
+		  TorrentMan* torrentMan);
   ~PeerInteraction();
 
-  void addMessage(PeerMessage* peerMessage);
+  void addMessage(const PeerMessageHandle& peerMessage);
   void rejectPieceMessageInQueue(int index, int begin, int length);
   void rejectAllPieceMessageInQueue();
   void onChoked();
@@ -116,8 +119,8 @@ public:
   void sendBitfield();
   void sendAllowedFast();
 
-  PeerMessage* receiveMessage();
-  HandshakeMessage* receiveHandshake(bool quickReply = false);
+  PeerMessageHandle receiveMessage();
+  HandshakeMessageHandle receiveHandshake(bool quickReply = false);
 
   RequestMessage* createRequestMessage(int index, int blockIndex);
   CancelMessage* createCancelMessage(int index, int begin, int length);
diff --git a/src/PeerInteractionCommand.cc b/src/PeerInteractionCommand.cc
index 89d536fd..555cc7db 100644
--- a/src/PeerInteractionCommand.cc
+++ b/src/PeerInteractionCommand.cc
@@ -28,28 +28,30 @@
 #include "prefs.h"
 #include <algorithm>
 
-PeerInteractionCommand::PeerInteractionCommand(int cuid, Peer* peer,
+PeerInteractionCommand::PeerInteractionCommand(int cuid,
+					       const PeerHandle& p,
 					       TorrentDownloadEngine* e,
-					       const Socket* s, int sequence)
-  :PeerAbstractCommand(cuid, peer, e, s), sequence(sequence) {
+					       const SocketHandle& s,
+					       int sequence)
+  :PeerAbstractCommand(cuid, p, e, s), sequence(sequence) {
   if(sequence == INITIATOR_SEND_HANDSHAKE) {
-    setReadCheckSocket(NULL);
+    disableReadCheckSocket();
     setWriteCheckSocket(socket);
     setTimeout(e->option->getAsInt(PREF_PEER_CONNECTION_TIMEOUT));
   }
-  peerInteraction = new PeerInteraction(cuid, socket, e->option,
-					e->torrentMan, this->peer);
+  peerInteraction = new PeerInteraction(cuid, peer, socket, e->option,
+					e->torrentMan);
   peerInteraction->setUploadLimit(e->option->getAsInt(PREF_UPLOAD_LIMIT));
   setUploadLimit(e->option->getAsInt(PREF_UPLOAD_LIMIT));
   chokeUnchokeCount = 0;
   haveCount = 0;
   keepAliveCount = 0;
-  e->torrentMan->addActivePeer(this->peer);
+  e->torrentMan->addActivePeer(peer);
 }
 
 PeerInteractionCommand::~PeerInteractionCommand() {
   delete peerInteraction;
-  e->torrentMan->deleteActivePeer(this->peer);
+  e->torrentMan->deleteActivePeer(peer);
 }
 
 bool PeerInteractionCommand::executeInternal() {
@@ -58,7 +60,7 @@ bool PeerInteractionCommand::executeInternal() {
     setReadCheckSocket(socket);
     setTimeout(e->option->getAsInt(PREF_TIMEOUT));
   }
-  setWriteCheckSocket(NULL);
+  disableWriteCheckSocket();
   setUploadLimitCheck(false);
 
   switch(sequence) {
@@ -73,15 +75,15 @@ bool PeerInteractionCommand::executeInternal() {
 	break;
       }
     }
-    HandshakeMessage* handshakeMessage = peerInteraction->receiveHandshake();
-    if(handshakeMessage == NULL) {
+    HandshakeMessageHandle handshakeMessage =
+      peerInteraction->receiveHandshake();
+    if(handshakeMessage.get() == NULL) {
       break;
     }
     peer->setPeerId(handshakeMessage->peerId);
     logger->info(MSG_RECEIVE_PEER_MESSAGE, cuid,
 		 peer->ipaddr.c_str(), peer->port,
 		 handshakeMessage->toString().c_str());
-    delete handshakeMessage;
     haveCheckTime.reset();
     peerInteraction->sendBitfield();
     peerInteraction->sendAllowedFast();
@@ -89,16 +91,15 @@ bool PeerInteractionCommand::executeInternal() {
     break;
   }
   case RECEIVER_WAIT_HANDSHAKE: {
-    HandshakeMessage* handshakeMessage =
+    HandshakeMessageHandle handshakeMessage =
       peerInteraction->receiveHandshake(true);
-    if(handshakeMessage == NULL) {
+    if(handshakeMessage.get() == NULL) {
       break;
     }
     peer->setPeerId(handshakeMessage->peerId);
     logger->info(MSG_RECEIVE_PEER_MESSAGE, cuid,
 		 peer->ipaddr.c_str(), peer->port,
 		 handshakeMessage->toString().c_str());
-    delete handshakeMessage;
     haveCheckTime.reset();
     peerInteraction->sendBitfield();
     peerInteraction->sendAllowedFast();
@@ -174,8 +175,8 @@ void PeerInteractionCommand::decideChoking() {
 
 void PeerInteractionCommand::receiveMessages() {
   for(int i = 0; i < 50; i++) {
-    PeerMessage* message = peerInteraction->receiveMessage();
-    if(message == NULL) {
+    PeerMessageHandle message = peerInteraction->receiveMessage();
+    if(message.get() == NULL) {
       return;
     }
     logger->info(MSG_RECEIVE_PEER_MESSAGE, cuid,
@@ -200,23 +201,18 @@ void PeerInteractionCommand::receiveMessages() {
       haveCount++;
       break;
     }
-    try {
-      message->receivedAction();
-      delete message;
-    } catch(Exception* ex) {
-      delete message;
-      throw;
-    }
+    message->receivedAction();
   }
 }
 
 // TODO this method removed when PeerBalancerCommand is implemented
 bool PeerInteractionCommand::prepareForNextPeer(int wait) {
   if(e->torrentMan->isPeerAvailable()) {
-    Peer* peer = e->torrentMan->getPeer();
+    PeerHandle peer = e->torrentMan->getPeer();
     int newCuid = e->torrentMan->getNewCuid();
     peer->cuid = newCuid;
-    PeerInitiateConnectionCommand* command = new PeerInitiateConnectionCommand(newCuid, peer, e);
+    PeerInitiateConnectionCommand* command =
+      new PeerInitiateConnectionCommand(newCuid, peer, e);
     e->commands.push_back(command);
   }
   return true;
diff --git a/src/PeerInteractionCommand.h b/src/PeerInteractionCommand.h
index 9de8c9b7..037f9029 100644
--- a/src/PeerInteractionCommand.h
+++ b/src/PeerInteractionCommand.h
@@ -57,7 +57,9 @@ protected:
   bool prepareForNextPeer(int wait);
   void onAbort(Exception* ex);
 public:
-  PeerInteractionCommand(int cuid, Peer* peer, TorrentDownloadEngine* e, const Socket* s, int sequence);
+  PeerInteractionCommand(int cuid, const PeerHandle& peer,
+			 TorrentDownloadEngine* e,
+			 const SocketHandle& s, int sequence);
   ~PeerInteractionCommand();
 
   enum Seq {
diff --git a/src/PeerListenCommand.cc b/src/PeerListenCommand.cc
index 43e00d3a..d81e16a0 100644
--- a/src/PeerListenCommand.cc
+++ b/src/PeerListenCommand.cc
@@ -23,13 +23,9 @@
 #include "PeerInteractionCommand.h"
 
 PeerListenCommand::PeerListenCommand(int cuid, TorrentDownloadEngine* e)
-  :Command(cuid), e(e), socket(NULL) {}
+  :Command(cuid), e(e) {}
 
-PeerListenCommand::~PeerListenCommand() {
-  if(socket != NULL) {
-    delete socket;
-  }
-}
+PeerListenCommand::~PeerListenCommand() {}
 
 int PeerListenCommand::bindPort(int portRangeStart, int portRangeEnd) {
   if(portRangeStart > portRangeEnd) {
@@ -37,7 +33,6 @@ int PeerListenCommand::bindPort(int portRangeStart, int portRangeEnd) {
   }
   for(int port = portRangeStart; port <= portRangeEnd; port++) {
     try {
-      socket = new Socket();
       socket->beginListen(port);
       logger->info("CUID#%d - using port %d for accepting new connections",
 		   cuid, port);
@@ -45,9 +40,8 @@ int PeerListenCommand::bindPort(int portRangeStart, int portRangeEnd) {
     } catch(Exception* ex) {
       logger->error("CUID#%d - an error occurred while binding port=%d",
 		    ex, cuid, port);
+      socket->closeConnection();
       delete ex;
-      delete socket;
-      socket = NULL;
     }
   }
   return -1;
@@ -57,44 +51,33 @@ bool PeerListenCommand::execute() {
   if(e->torrentMan->isHalt()) {
     return true;
   }
-  try {
-    for(int i = 0; i < 3 && socket->isReadable(0); i++) {
-      Socket* peerSocket = NULL;
-      try {
-	peerSocket = socket->acceptConnection();
-	pair<string, int> peerInfo;
-	peerSocket->getPeerInfo(peerInfo);
-	pair<string, int> localInfo;
-	peerSocket->getAddrInfo(localInfo);
-	if(peerInfo.first != localInfo.first &&
-	   e->torrentMan->connections < MAX_PEERS) {
-	  Peer* peer = new Peer(peerInfo.first, peerInfo.second,
-				e->torrentMan->pieceLength,
-				e->torrentMan->getTotalLength());
-	  if(e->torrentMan->addPeer(peer, true)) {
-	    int newCuid =  e->torrentMan->getNewCuid();
-	    peer->cuid = newCuid;
-	    PeerInteractionCommand* command =
-	      new PeerInteractionCommand(newCuid, peer, e, peerSocket,
-					 PeerInteractionCommand::RECEIVER_WAIT_HANDSHAKE);
-	    e->commands.push_back(command);
-	    logger->debug("CUID#%d - incoming connection, adding new command CUID#%d", cuid, newCuid);
-	  } else {
-	    delete peer;
-	  }
-	}
-	delete peerSocket;
-      } catch(Exception* ex) {
-	logger->error("CUID#%d - error in accepting connection", ex, cuid);
-	delete ex;
-	if(peerSocket != NULL) {
-	  delete peerSocket;
+  for(int i = 0; i < 3 && socket->isReadable(0); i++) {
+    SocketHandle peerSocket;
+    try {
+      peerSocket = socket->acceptConnection();
+      pair<string, int> peerInfo;
+      peerSocket->getPeerInfo(peerInfo);
+      pair<string, int> localInfo;
+      peerSocket->getAddrInfo(localInfo);
+      if(peerInfo.first != localInfo.first &&
+	 e->torrentMan->connections < MAX_PEERS) {
+	PeerHandle peer = PeerHandle(new Peer(peerInfo.first, peerInfo.second,
+					      e->torrentMan->pieceLength,
+					      e->torrentMan->getTotalLength()));
+	if(e->torrentMan->addPeer(peer)) {
+	  int newCuid =  e->torrentMan->getNewCuid();
+	  peer->cuid = newCuid;
+	  PeerInteractionCommand* command =
+	    new PeerInteractionCommand(newCuid, peer, e, peerSocket,
+				       PeerInteractionCommand::RECEIVER_WAIT_HANDSHAKE);
+	  e->commands.push_back(command);
+	  logger->debug("CUID#%d - incoming connection, adding new command CUID#%d", cuid, newCuid);
 	}
-      }		    
-    }
-  } catch(Exception* e) {
-    logger->error("CUID#%d - Exception occurred.", e, cuid);
-    delete e;
+      }
+    } catch(Exception* ex) {
+      logger->error("CUID#%d - error in accepting connection", ex, cuid);
+      delete ex;
+    }		    
   }
   e->commands.push_back(this);
   return false;
diff --git a/src/PeerListenCommand.h b/src/PeerListenCommand.h
index c4a33e68..03ddc84a 100644
--- a/src/PeerListenCommand.h
+++ b/src/PeerListenCommand.h
@@ -28,7 +28,7 @@
 class PeerListenCommand : public Command {
 private:
   TorrentDownloadEngine* e;
-  Socket* socket;
+  SocketHandle socket;
 public:
   PeerListenCommand(int cuid, TorrentDownloadEngine* e);
   ~PeerListenCommand();
diff --git a/src/PeerMessage.h b/src/PeerMessage.h
index 4170aa8b..467f3c6d 100644
--- a/src/PeerMessage.h
+++ b/src/PeerMessage.h
@@ -33,7 +33,7 @@ class PeerMessage {
 protected:
   bool inProgress;
   int cuid;
-  Peer* peer;
+  PeerHandle peer;
   PeerInteraction* peerInteraction;
   const Logger* logger;
 public:
@@ -47,8 +47,8 @@ public:
   void setCuid(int cuid) {
     this->cuid = cuid;
   }
-  Peer* getPeer() const { return this->peer; }
-  void setPeer(Peer* peer) {
+  PeerHandle getPeer() const { return this->peer; }
+  void setPeer(const PeerHandle& peer) {
     this->peer = peer;
   }
   PeerInteraction* getPeerInteraction() const { return peerInteraction; }
diff --git a/src/Socket.h b/src/Socket.h
index 5667f207..f909dcea 100644
--- a/src/Socket.h
+++ b/src/Socket.h
@@ -22,101 +22,9 @@
 #ifndef _D_SOCKET_H_
 #define _D_SOCKET_H_
 
-#include <string>
 #include "SocketCore.h"
-#include "common.h"
+#include "SharedHandle.h"
 
-using namespace std;
-
-class Socket {
-private:
-  SocketCore* core;
-  /**
-   * This method doesn't increment the use count of core.
-   */
-  Socket(SocketCore* core);
-public:
-  Socket();
-  Socket(const Socket& s);
-  ~Socket();
-
-  Socket& operator=(const Socket& s);
-
-  /**
-   * Returns socket descriptor of this socket.
-   * @returns socket descriptor of this socket.
-   */
-  int getSockfd() const { return core->sockfd; }
-
-  /**
-   * @see SocketCore::beginListen()
-   */
-  void beginListen(int port = 0) const;
-  
-  /**
-   * @see SocketCore::getAddrInfo()
-   */
-  void getAddrInfo(pair<string, int>& addrinfo) const;
-
-  /**
-   * @see SocketCore::getPeerInfo();
-   */
-  void getPeerInfo(pair<string, int>& peerinfo) const;
-
-  /**
-   * @see SocketCore::acceptConnection()
-   */
-  Socket* acceptConnection() const;
-
-  /**
-   * @see SocketCore::establishConnection()
-   */
-  void establishConnection(const string& host, int port) const;
-
-  /**
-   * @see SocketCore::setBlockingMode()
-   */
-  void setBlockingMode() const;
-
-  /**
-   * @see SocketCore::closeConnection()
-   */
-  void closeConnection() const;
-
-  /**
-   * @see SocketCore::isWritable()
-   */
-  bool isWritable(int timeout) const;
-
-  /**
-   * @see SocketCore::isReadable()
-   */
-  bool isReadable(int timeout) const;
-
-  /**
-   * @see SocketCore::writeData()
-   */
-  void writeData(const char* data, int len) const;
-  /**
-   * A covenient function that can take string class parameter and
-   * internally calls SocketCore::writeData().
-   */
-  void writeData(const string& str) const;
-
-  /**
-   * @see SocketCore::readData()
-   */
-  void readData(char* data, int& len) const;
-
-  /**
-   * @see SocketCore::peekData()
-   */
-  void peekData(char* data, int& len) const;
-
-  /**
-   * @see SocketCore::initiateSecureConnection()
-   */
-  void initiateSecureConnection() const;
-};
+typedef SharedHandle<SocketCore> SocketHandle;
 
 #endif // _D_SOCKET_H_
diff --git a/src/SocketCore.cc b/src/SocketCore.cc
index acac581b..8936f0c3 100644
--- a/src/SocketCore.cc
+++ b/src/SocketCore.cc
@@ -456,3 +456,14 @@ void SocketCore::initiateSecureConnection() {
 #endif // HAVE_LIBGNUTLS
 }
 
+bool operator==(const SocketCore& s1, const SocketCore& s2) {
+  return s1.sockfd == s2.sockfd;
+}
+
+bool operator!=(const SocketCore& s1, const SocketCore& s2) {
+  return s1.sockfd != s2.sockfd;
+}
+
+bool operator<(const SocketCore& s1, const SocketCore& s2) {
+  return s1.sockfd < s2.sockfd;
+}
diff --git a/src/SocketCore.h b/src/SocketCore.h
index 06cdf0dd..f49f8d41 100644
--- a/src/SocketCore.h
+++ b/src/SocketCore.h
@@ -22,9 +22,9 @@
 #ifndef _D_SOCKET_CORE_H_
 #define _D_SOCKET_CORE_H_
 
+#include "common.h"
 #include <string>
 #include <utility>
-#include "common.h"
 
 #ifdef HAVE_LIBSSL
 // for SSL
@@ -37,7 +37,9 @@
 using namespace std;
 
 class SocketCore {
-  friend class Socket;
+  friend bool operator==(const SocketCore& s1, const SocketCore& s2);
+  friend bool operator!=(const SocketCore& s1, const SocketCore& s2);
+  friend bool operator<(const SocketCore& s1, const SocketCore& s2);
 private:
   // socket endpoint descriptor
   int sockfd;
@@ -68,6 +70,10 @@ public:
   SocketCore();
   ~SocketCore();
 
+  int getSockfd() const { return sockfd; }
+
+  bool isOpen() const { return sockfd != -1; }
+
   /**
    * Creates a socket and listens form connection on it.
    * @param port port to listen. If 0 is specified, os automaticaly
@@ -143,6 +149,7 @@ public:
    * @param len length of data
    */
   void writeData(const char* data, int len);
+  void writeData(const string& msg) { writeData(msg.c_str(), msg.size()); }
 
   /**
    * Reads up to len bytes from this socket.
@@ -176,5 +183,4 @@ public:
    */
   void initiateSecureConnection() ;
 };
-
 #endif // _D_SOCKET_CORE_H_
diff --git a/src/TorrentMan.cc b/src/TorrentMan.cc
index 97f8dcea..7cd26417 100644
--- a/src/TorrentMan.cc
+++ b/src/TorrentMan.cc
@@ -41,18 +41,28 @@
 #include <string.h>
 #include <algorithm>
 
+extern PeerHandle nullPeer;
+
 TorrentMan::TorrentMan():bitfield(NULL),
-			 peerEntryIdCounter(0), cuidCounter(0),
-			 downloadLength(0), uploadLength(0),
-			 preDownloadLength(0), preUploadLength(0),
-			 deltaDownloadLength(0), deltaUploadLength(0),
+			 peerEntryIdCounter(0),
+			 cuidCounter(0),
+			 downloadLength(0),
+			 uploadLength(0),
+			 preDownloadLength(0),
+			 preUploadLength(0),
+			 deltaDownloadLength(0),
+			 deltaUploadLength(0),
 			 storeDir("."),
 			 setupComplete(false),
 			 halt(false),
 			 interval(DEFAULT_ANNOUNCE_INTERVAL),
 			 minInterval(DEFAULT_ANNOUNCE_MIN_INTERVAL),
-			 complete(0), incomplete(0),
-			 connections(0), trackers(0), diskAdaptor(NULL) {
+			 complete(0),
+			 incomplete(0),
+			 connections(0),
+			 trackers(0),
+			 diskAdaptor(NULL)
+{
   logger = LogFactory::getInstance();
 }
 
@@ -60,9 +70,6 @@ TorrentMan::~TorrentMan() {
   if(bitfield != NULL) {
     delete bitfield;
   }
-  for(Peers::iterator itr = peers.begin(); itr != peers.end(); itr++) {
-    delete *itr;
-  }
   if(diskAdaptor != NULL) {
     delete diskAdaptor;
   }
@@ -73,32 +80,25 @@ void TorrentMan::updatePeers(const Peers& peers) {
   this->peers = peers;
 }
 
-bool TorrentMan::addPeer(Peer* peer, bool duplicate) {
+bool TorrentMan::addPeer(const PeerHandle& peer) {
   if(peers.size() >= MAX_PEER_LIST_SIZE) {
-    deleteOldErrorPeers();
+    deleteErrorPeer();
   }
-  if(duplicate) {
-    for(Peers::iterator itr = peers.begin(); itr != peers.end(); itr++) {
-      Peer* p = *itr;
-      if(p->ipaddr == peer->ipaddr && p->port == peer->port && p->error > 0) {
-	return false;
-      }
-    }
+  Peers::iterator itr = find(peers.begin(), peers.end(), peer);
+  if(itr == peers.end()) {
+    ++peerEntryIdCounter;
+    peer->entryId = peerEntryIdCounter;
+    peers.push_back(peer);
+    return true;
   } else {
-    if(peers.size() >= MAX_PEER_LIST_SIZE) {
+    const PeerHandle& peer = *itr;
+    if(peer->error >= MAX_PEER_ERROR || peer->cuid != 0) {
       return false;
-    }
-    for(Peers::iterator itr = peers.begin(); itr != peers.end(); itr++) {
-      Peer* p = *itr;
-      if(p->ipaddr == peer->ipaddr && p->port == peer->port) {
-	return false;
-      }
-    }
+    } else {
+      *itr = peer;
+      return true;
+    }      
   }
-  ++peerEntryIdCounter;
-  peer->entryId = peerEntryIdCounter;
-  peers.push_back(peer);
-  return true;
 }
 
 /*
@@ -114,14 +114,13 @@ void TorrentMan::updatePeer(const Peer& peer) {
 */
 
 bool TorrentMan::isPeerAvailable() const {
-  return getPeer() != Peer::nullPeer;
+  return getPeer() != nullPeer;
 }
 
-void TorrentMan::deleteOldErrorPeers() {
+void TorrentMan::deleteErrorPeer() {
   for(Peers::iterator itr = peers.begin(); itr != peers.end();) {
-    Peer* p = *itr;
-    if(p->error >= MAX_PEER_ERROR && p->cuid == 0) {
-      delete p;
+    const PeerHandle& p = *itr;
+    if(p->error > 0 && p->cuid == 0) {
       itr = peers.erase(itr);
     } else {
       itr++;
@@ -129,29 +128,29 @@ void TorrentMan::deleteOldErrorPeers() {
   }
 }
 
-Peer* TorrentMan::getPeer() const {
-  if(connections > MAX_PEER_UPDATE) {
-    return Peer::nullPeer;
+PeerHandle TorrentMan::getPeer() const {
+  if(connections > MIN_PEERS) {
+    return nullPeer;
   }
   for(Peers::const_iterator itr = peers.begin(); itr != peers.end(); itr++) {
-    Peer* p = *itr;
+    const PeerHandle& p = *itr;
     if(p->cuid == 0 && p->error < MAX_PEER_ERROR) {
       return p;
     }
   }
-  return Peer::nullPeer;
+  return nullPeer;
 }
 
 bool TorrentMan::isEndGame() const {
   return bitfield->countMissingBlock() <= END_GAME_PIECE_NUM;
 }
 
-bool TorrentMan::hasMissingPiece(const Peer* peer) const {
+bool TorrentMan::hasMissingPiece(const PeerHandle& peer) const {
   return bitfield->hasMissingPiece(peer->getBitfield(),
 				   peer->getBitfieldLength());
 }
 
-int TorrentMan::getMissingPieceIndex(const Peer* peer) const {
+int TorrentMan::getMissingPieceIndex(const PeerHandle& peer) const {
   int index = -1;
   if(isEndGame()) {
     index = bitfield->getMissingIndex(peer->getBitfield(),
@@ -163,7 +162,7 @@ int TorrentMan::getMissingPieceIndex(const Peer* peer) const {
   return index;
 }
 
-int TorrentMan::getMissingFastPieceIndex(const Peer* peer) const {
+int TorrentMan::getMissingFastPieceIndex(const PeerHandle& peer) const {
   int index = -1;
   if(peer->isFastExtensionEnabled() && peer->countFastSet() > 0) {
     BitfieldMan tempBitfield(pieceLength, totalLength);
@@ -184,12 +183,12 @@ int TorrentMan::getMissingFastPieceIndex(const Peer* peer) const {
   return index;
 }
 
-Piece TorrentMan::getMissingFastPiece(const Peer* peer) {
+Piece TorrentMan::getMissingFastPiece(const PeerHandle& peer) {
   int index = getMissingFastPieceIndex(peer);
   return checkOutPiece(index);
 }
 
-Piece TorrentMan::getMissingPiece(const Peer* peer) {
+Piece TorrentMan::getMissingPiece(const PeerHandle& peer) {
   int index = getMissingPieceIndex(peer);
   return checkOutPiece(index);
 }
diff --git a/src/TorrentMan.h b/src/TorrentMan.h
index 972d5059..6155efca 100644
--- a/src/TorrentMan.h
+++ b/src/TorrentMan.h
@@ -46,7 +46,7 @@ using namespace std;
 #define DEFAULT_ANNOUNCE_INTERVAL 1800
 #define DEFAULT_ANNOUNCE_MIN_INTERVAL 1800
 #define MAX_PEERS 55
-#define MAX_PEER_UPDATE 15
+#define MIN_PEERS 15
 #define MAX_PEER_LIST_SIZE 250
 #define END_GAME_PIECE_NUM 20
 #define MAX_PEER_ERROR 5
@@ -61,7 +61,7 @@ public:
     index(index) {}
 };
 
-typedef deque<Peer*> Peers;
+typedef deque<PeerHandle> Peers;
 typedef deque<HaveEntry> Haves;
 typedef deque<int> PieceIndexes;
 typedef deque<Piece> Pieces;
@@ -133,18 +133,18 @@ public:
 
   // TODO do not use this method
   void updatePeers(const Peers& peers);
-  bool addPeer(Peer* peer, bool duplicate = false);
+  bool addPeer(const PeerHandle& peer);
   //void updatePeer(const Peer* peer);
   const Peers& getPeers() const { return peers; }
-  Peer* getPeer() const;
+  PeerHandle getPeer() const;
   bool isPeerAvailable() const;
-  void deleteOldErrorPeers();
+  void deleteErrorPeer();
 
-  bool hasMissingPiece(const Peer* peer) const;
-  int getMissingPieceIndex(const Peer* peer) const;
-  int getMissingFastPieceIndex(const Peer* peer) const;
-  Piece getMissingPiece(const Peer* peer);
-  Piece getMissingFastPiece(const Peer* peer);
+  bool hasMissingPiece(const PeerHandle& peer) const;
+  int getMissingPieceIndex(const PeerHandle& peer) const;
+  int getMissingFastPieceIndex(const PeerHandle& peer) const;
+  Piece getMissingPiece(const PeerHandle& peer);
+  Piece getMissingFastPiece(const PeerHandle& peer);
   void completePiece(const Piece& piece);
   void cancelPiece(const Piece& piece);
   void updatePiece(const Piece& piece);
@@ -246,15 +246,17 @@ public:
 
   void onDownloadComplete();
 
-  void addActivePeer(Peer* peer) {
+  void addActivePeer(const PeerHandle& peer) {
     activePeers.push_back(peer);
   }
 
   Peers& getActivePeers() { return this->activePeers; }
 
-  void deleteActivePeer(Peer* peer) {
+  void deleteActivePeer(const PeerHandle& peer) {
     Peers::iterator itr = find(activePeers.begin(), activePeers.end(), peer);
-    activePeers.erase(itr);
+    if(itr != activePeers.end()) {
+      activePeers.erase(itr);
+    }
   }
 
   bool isHalt() const { return halt; }
diff --git a/src/TrackerUpdateCommand.cc b/src/TrackerUpdateCommand.cc
index 0998ccd1..49fe6f3a 100644
--- a/src/TrackerUpdateCommand.cc
+++ b/src/TrackerUpdateCommand.cc
@@ -69,24 +69,14 @@ bool TrackerUpdateCommand::execute() {
   if(!e->segmentMan->finished()) {
     return prepareForRetry();
   }
-  MetaEntry* entry = NULL;
   char* trackerResponse = NULL;
   int trackerResponseLength = 0;
+
   try {
-    try {
-      trackerResponse = getTrackerResponse(trackerResponseLength);
-      entry = MetaFileUtil::bdecoding(trackerResponse,
-				      trackerResponseLength);
-      if(trackerResponse != NULL) {
-	delete [] trackerResponse;
-      }
-    } catch(Exception* e) {
-      if(trackerResponse != NULL) {
-	delete [] trackerResponse;
-      }
-      throw;
-    }
-    Dictionary* response = (Dictionary*)entry;
+    trackerResponse = getTrackerResponse(trackerResponseLength);
+    SharedHandle<MetaEntry> entry(MetaFileUtil::bdecoding(trackerResponse,
+							  trackerResponseLength));
+    Dictionary* response = (Dictionary*)entry.get();
     Data* failureReason = (Data*)response->get("failure reason");
     if(failureReason != NULL) {
       throw new DlAbortEx("Tracker returned failure reason: %s", failureReason->toString().c_str());
@@ -126,7 +116,9 @@ bool TrackerUpdateCommand::execute() {
       logger->debug("CUID#%d - Incomplete:%d",
 		    cuid, e->torrentMan->incomplete);
     }
-    if(dynamic_cast<const Data*>(response->get("peers"))) {
+    if(!e->torrentMan->isHalt() &&
+       e->torrentMan->connections < MIN_PEERS &&
+       dynamic_cast<const Data*>(response->get("peers"))) {
       Data* peers = (Data*)response->get("peers");
       if(peers != NULL && peers->getLen() > 0) {
 	for(int i = 0; i < peers->getLen(); i += 6) {
@@ -139,24 +131,24 @@ bool TrackerUpdateCommand::execute() {
 	  
 	  snprintf(ipaddr, sizeof(ipaddr), "%d.%d.%d.%d",
 		   ipaddr1, ipaddr2, ipaddr3, ipaddr4);
-	  Peer* peer = new Peer(ipaddr, port, e->torrentMan->pieceLength,
-				e->torrentMan->getTotalLength());
+	  PeerHandle peer =
+	    PeerHandle(new Peer(ipaddr, port, e->torrentMan->pieceLength,
+				e->torrentMan->getTotalLength()));
 	  if(e->torrentMan->addPeer(peer)) {
 	    logger->debug("CUID#%d - Adding peer %s:%d",
 			  cuid, peer->ipaddr.c_str(), peer->port);
-	  } else {
-	    delete peer;
 	  }
 	}
       } else {
 	logger->info("CUID#%d - No peer list received.", cuid);
       }
       while(e->torrentMan->isPeerAvailable() &&
-	    e->torrentMan->connections < MAX_PEER_UPDATE) {
-	Peer* peer = e->torrentMan->getPeer();
+	    e->torrentMan->connections < MIN_PEERS) {
+	PeerHandle peer = e->torrentMan->getPeer();
 	int newCuid =  e->torrentMan->getNewCuid();
 	peer->cuid = newCuid;
-	PeerInitiateConnectionCommand* command = new PeerInitiateConnectionCommand(newCuid, peer, e);
+	PeerInitiateConnectionCommand* command =
+	  new PeerInitiateConnectionCommand(newCuid, peer, e);
 	e->commands.push_back(command);
 	logger->debug("CUID#%d - Adding new command CUID#%d", cuid, newCuid);
       }
@@ -166,10 +158,10 @@ bool TrackerUpdateCommand::execute() {
     }
   } catch(Exception* err) {
     logger->error("CUID#%d - Error occurred while processing tracker response.", cuid, err);
-    delete(err);
+    delete err;
   }
-  if(entry != NULL) {
-    delete entry;
+  if(trackerResponse != NULL) {
+    delete [] trackerResponse;
   }
   e->torrentMan->trackers = 0;
 
diff --git a/src/TrackerWatcherCommand.h b/src/TrackerWatcherCommand.h
index 37708456..fd0cccf7 100644
--- a/src/TrackerWatcherCommand.h
+++ b/src/TrackerWatcherCommand.h
@@ -26,8 +26,6 @@
 #include "TorrentDownloadEngine.h"
 #include "Time.h"
 
-#define MIN_PEERS 15
-
 class TrackerWatcherCommand : public Command {
 private:
   TorrentDownloadEngine* e;
diff --git a/src/main.cc b/src/main.cc
index c46f360f..856c5090 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -870,16 +870,17 @@ int main(int argc, char* argv[]) {
       }
       te->torrentMan->setPort(port);
       te->commands.push_back(listenCommand);
+
       te->commands.push_back(new TrackerWatcherCommand(te->torrentMan->getNewCuid(),
 						       te,
 						       te->torrentMan->minInterval));
       te->commands.push_back(new TrackerUpdateCommand(te->torrentMan->getNewCuid(),
-						 te));
+						      te));
       te->commands.push_back(new TorrentAutoSaveCommand(te->torrentMan->getNewCuid(),
-						   te,
-						   op->getAsInt(PREF_AUTO_SAVE_INTERVAL)));
+							te,
+							op->getAsInt(PREF_AUTO_SAVE_INTERVAL)));
       te->commands.push_back(new PeerChokeCommand(te->torrentMan->getNewCuid(),
-					     10, te));
+						  10, te));
       te->run();
       
       if(te->torrentMan->downloadComplete()) {