/** @file

* Copyright (c) 2005-2006 Nokia Corporation and/or its subsidiary(-ies). 

* All rights reserved.

* This component and the accompanying materials are made available

* under the terms of "Eclipse Public License v1.0"

* which accompanies  this distribution, and is available 

* at the URL "http://www.eclipse.org/legal/epl-v10.html".

*

* Initial Contributors:

* Nokia Corporation - initial contribution.

*

* Contributors:

*

* Description:  Class that is derived by CUpnpHttpSession. Implements TCP-level

*                functionalities

*

*/

#ifndef C_CUPNPTCPSESSION_H

#define C_CUPNPTCPSESSION_H

// INCLUDES

#include <e32base.h>

#include "upnphttpmessage.h"

#include "upnplist.h" 

#include "upnpnotifytimer.h"

#include "upnpsocketshutdown.h"

// FORWARD DECLARATIONS

class CUpnpHttpBuffer;

class CUpnpHttpServer;

class CUpnpSocketShutdown;

class RSocket;

class CUpnpTcpSessionWriter;

class CUpnpHttpFileTransferReader;

class CUpnpHttpFileTransferWriter;

class CUpnpTcpSessionReader;

class CUpnpHttpFileAccess;

// CONSTANTS

static const TInt KErrorTimeout = 3000000;

//when reading from a file

static const TInt KServeFileSizeDefault = 10000;

// Based on 7.2.9.4 (DLNA 1.5 rev 0.90)

// We need wait until 30second for response

static const TInt KSessionTimeout = 35000000; 

static const TInt KConnectTimeout = 7000000;

//default buffer size for reading from socket

static const TInt KRcvBufSizeDefault = 10000;

//default size for fiel content reading from a socket, must be a power of 2

static const TInt KFileTransferReaderBufSizeDefault = 16384;

//timeout value for awaiting 100 continue

static const TInt K100ContinueTimeout = 5000000;

// CLASS DECLARATION

/**

*  @brief CUpnpTcpSession is a class handling TCP functionality of the session.

*   Class is responsible for managing connection and its timeout as well as

*   for reading from and writing to socket. Those two last are directly 

*   handled by CUpnpTcpSessionReader and CUpnpTcpSessionWriter but CUpnpTcpSession 

*   supervises those processes.

*  @lib DLNAWebServer.lib

*  @since Series60 2.6

*/  

NONSHARABLE_CLASS (CUpnpTcpSession) : public CBase, public MUpnpNotifyTimerObserver

    {

       friend class CUpnpSocketShutdown;        

public: // Constructors and destructor

    /** 

    * Constructor for building CUpnpTcpSession. 

    * This constructor is used when connection is iniatiated from network.

    * Second-phase construction is made by TcpConstructL().

    * @param aSocket Pointer to new Socket.

    * @param aPriority Priority of this session

    * @return A new CUpnpTcpServer instance.

    **/

    CUpnpTcpSession( RSocket& aSocket, TThreadPriority aPriority );

    /** 

    * Virtual destructor.

    **/

    virtual ~CUpnpTcpSession();

public: // Session functionality

    void ShutdownStop();

    /**

    * Starts to receive messages to this session

    * @since Series60 3.2

    * @return None.

    **/

    void InitialReceiveL();

    /**

    * Receive messages to this session

    * @since Series60 3.2

    * @return None.

    **/

    void ReceiveL();

    /**

    * Writes data thru this session's socket

    * @since Series60 2.6

    * @param aBuffer Data to write.

    * @return None.

    **/

    void WriteL( const TDesC8& aBuffer );

    /**

    * Checks is session is connected.

    * @since Series60 2.6

    * @return ETrue, if session is connected; EFalse othewise.

    **/

    TBool IsConnected();

    /**

    * Returns the address that session is connected to.

    * @since Series60 2.6

    * @return Address of remote endpoint of session's socket.

    **/

    TInetAddr& RemoteHost();

    /**

    * Starts the timeoutTimer for session. If timer expires, no reply has 

    * been sent to remote host.

    * @since Series60 2.6

    * @param aSessionErrorReplyNeeded ETrue, if in timeout there should be

    * sent HTTP error 408 Server timeout.

    **/

    void StartTimeoutTimer( TBool aSessionErrorReplyNeeded );

    /**

    * Starts the timeoutTimer for session. Session is deleted after 0.5ms by default.

    * @since Series60 2.6

    **/

    void StartDisconnectingTimer(TInt aTime = 500);

    /**

    * Starts disconnect session.

    * @since Series60 3.2

    **/

    void StartDisconnect( TBool aDisconnectNotification = EFalse );

    /**

    * Function that is used to send notification to client and disconnect 

    * the session.

    * @since Series60 2.6

    **/

    void ServerBusyL();

    /**

    * Returns the SessionId of this session.

    * @since Series60 3.1

    * @return SessionId.

    **/

    TInt Id();

public: // Callback functions for reader and writer

    /**

    * Handles possible error that can occure in the session as well as

    * in reader and writer active objects.

    * @since Series60 3.0

    * @param aError error code

    **/

    void HandleErrorL( TInt aError  );

    /**

    * Callback function for reader object. When the reader gets some 

    * data, it forwards it to the session with this callback.

    * @since Series60 3.0

    * @param aBuffer buffer with received data.

    **/

    void ReceivingCompletedL( TDesC8& aBuffer );

    /**

    * Callback function for writer object. When the request writing is

    * completed then writer calls this function to notify session about it.

    * @since Series60 3.0

    **/

    void WritingCompletedL();

    /**

    * Callback function for writer object. When the request writing is

    * not completed due to an error, a new attempt to write is being made...

    * @since Series60 3.2

    **/

    void WaitRetryError(TInt aError, TBool aStartTimer = EFalse);    

     /** 

    * Second phase constructor for building CUpnpTcpSession. 

    * This constructor is used when connection is iniatiated from network.

    * @param aSocket Pointer to new Socket which is already connected 

    *  to remote host.

    * @return None

    **/

    void TcpConstructL( RSocket aSocket, TInt aReadBufferSize, TInt aFileReadBufferSize );

    /** 

    * Cancels TcpReader

    * @return None.

    **/

    void CancelTcpReader();

public: // virtual callback functions

    /**

    * Callback function. Called when data has been received.

    * @since Series60 2.6

    * @param aBuffer Data that has been received thru session.

    **/

    virtual void BufferReceivedL( TDesC8& aBuffer ) = 0;

    /**

    * Callback function. Deletes given session.

    * @since Series60 2.6

    * @param aSession Session to delete.

    **/

    virtual void DeleteThisSessionL( CUpnpTcpSession* aSession ) = 0;

    /**

    * Checks if FileServe Exists.

    * @since Series60 2.6

    * @return ETrue, if fileServe exists; EFalse otherwise.

    **/

    virtual TBool FileServeExists() = 0;

    /**

    * Callback function. Notifies upper layers that session has been disconnected.

    * @since Series60 2.6

    * @param aAddr Address of remote host.

    **/

    virtual void NotifyDisconnectL( TInetAddr aAddr ) = 0;

    virtual void NotifyTimeoutL() = 0;

    //file transfer reader callbacks

    /**

    * Callback function. Notifies http session when upload finished

    * @since Series60 3.2    

    **/

    virtual void FileTransferReaderDoneL() = 0;

    /**

    * Callback function. Notifies http session when error in upload

    * @since Series60 3.2    

    **/

    virtual void FileTransferReaderErrorL(TInt aError) = 0;

    /**

    * Callback function. Notifies http session when download finished

    * @since Series60 3.2    

    **/

    virtual void FileTransferWriterDoneL() = 0;

    /**

    * Callback function. Checks for outstanding downloads

    * @since Series60 3.2    

    **/

    virtual void FileTransferWriterHandleMoreL() = 0;

    /**

    * Callback function. Notifies upper layers that SocketServer is busy.

    * @since Series60 2.6

    * @param aAddr Address of remote host.

    **/

    virtual void SocketServerBusyL( const TInetAddr& aAddr ) = 0;

    /**

    * Callback function. Deletes fileserve of this session.

    * @since Series60 2.6

    **/

    virtual void DeleteServeFileL() = 0;

    /**

    * Returns a pointer to FileAccess object of this session.

    * @since Series60 3.2

    * @return Pointer to FileAccess object.

    **/

    virtual CUpnpHttpFileAccess* FileAccess()=0;

    /**

    * Callback function. Returns the port number of parent HttpServer.

    * @since Series60 2.6

    * @return Portnumber of http server.

    **/

    virtual TInt ServerPort() = 0;

    /**

    * Callback function. Checks if connection uses Connection: Close 

    * header, and if so, tries to parse message and send it to upper layers.

    * @since Series60 2.6

    **/

    virtual void CheckConnectionCloseL() = 0;

    /**

    * Callback function. Informs upper layers that HTTP POST has been started 

    * by sending HTTP error code 801 message to upper layers.

    * @since Series60 2.6

    **/

    virtual void NotifyUpperLayersOnPostL() = 0;

    /**

    * Callback function. Informs upper layers that HTTP POST has been finished 

    * @since Series60 2.6

    **/

    virtual void PostingFileCompleteL() = 0;

public: // From MNotifyTimeObserver

    /**

    * Callback function for timer expirations.

    * @since Series60 2.6

    * @param aTimer Timer that has expired.

    **/

    void TimerEventL( CUpnpNotifyTimer* aTimer );   

    /**

    * Cancel timer

    * @since Series60 3.2

    **/

    void TimerCancel();

    /**

    * Handles disconnect request

    * @since Series60 3.2

    **/

    void DisconnectRequestL();      

    /**

    * Starts closing the session, no more message to be sent to the client

    * @since Series60 3.2

    **/

    void StartClosingSession();

     /**

    * Marked if a persistent connection

    * @since Series60 3.2

    **/

    TBool IsPersistentConnection();

     /**

    * Returns pointer to CUpnpHttpFileTransferReader

    * @since Series60 3.2

    * @return CUpnpHttpFileTransferReader*

    **/

    CUpnpHttpFileTransferReader* FileTransferReader();

     /**

    * Returns pointer to CUpnpHttpFileTransferWriter

    * @since Series60 3.2

    * @return CUpnpHttpFileTransferWriter*

    **/

    CUpnpHttpFileTransferWriter* FileTransferWriter();

    /**

    * Checks if there are outstanding sending operations.

    * @since Series60 3.2

    * @return TBool

    **/

    TBool DownloadOngoing();

    /**

    * Checks if the session is being shutdown

    * @since Series60 3.2

    * @return TBool

    **/

    TBool ShuttingDown() ;

      /**

    * Returns current value of the timeout

    * @since Series60 3.2

    * @return TInt

    */

     /**

    * Closes the socket

    * @since Series60 3.2

    */

    void CloseSocketL();

    TInt TimeoutCurrentValue();  

private: // private enumerations

    /**

    * State of session.

    *   - EnotConnected - Connection is not established yet.

    *   - EConnecting - TcpSession requested connection in asynchronous mode.

    *   - EConnected  - Connection is established, TcpReader is started and TcpWriter 

    *                 can write to the socket.

    *   - EDisconnecting - Session is about to be disconnected but socket is not closed

    *                 so TcpWriter can still write a response.

    *   - EServerBusy - Server is already occupied with processing requests so no other

    *                 session can be established.

    **/

    enum TUpnpTcpSessionState 

      {

      ENotConnected,

      EConnecting,

      EConnected,

      EDisconnecting,

      EShuttingDownWriteWait,

      EShuttingDownStop,

      EShuttingDown,

      EServerBusy

      };

private: // New functions

    /**

    * Sets session statel.

    * @since Series60 2.6

    * @param aState new state of the session.

    **/

    void SetState( TUpnpTcpSessionState aState );

    /**

    * Checks if there are outstanding writing operations.

    * @since Series60 3.2

    * @return TBool

    **/

    TBool OutstandingWritings();

protected:

     /**

    * Contructs file transfer reader

    * @since Series60 3.2

    **/

    void FileTransferReaderConstructL();

    virtual void DestroyIt(CUpnpTcpSession* aSession ) = 0;

    /**

    * Contructs file transfer writer

    * @since Series60 3.2

    **/

    void FileTransferWriterConstructL(TInt aWriteSize);    

protected:  

    TInt iFileReadBufferSize;

    // Session's socket, owned

    RSocket iSocket;

    // Address of remote host, owned

    TInetAddr iAddr;

    // iTcpReader, active object to control reads from the socket.

    // Owned by CUpnpTcpSession object.

    CUpnpTcpSessionReader* iTcpReader;

    // iFileTransferReader, active object to control reads from the socket.

    // Owned by CUpnpTcpSession object.

    CUpnpHttpFileTransferReader* iFTReader;

    // iFileTransferWriter, active object to control writes from the socket.

    // Owned by CUpnpTcpSession object.

    CUpnpHttpFileTransferWriter* iFTWriter;

    // iTcpWriter, active object to control writes to the socket.

    // Owned by CUpnpTcpSession object.

    CUpnpTcpSessionWriter* iTcpWriter;

    // Timer that is used to disconnect session when timeout expires, owned

    CUpnpNotifyTimer* iTimeoutTimer;

    // Buffer that is used to receive messages. See CUpnpHttpBuffer.

    CUpnpHttpBuffer* iReceivedMessage;

    // Session id of this session, owned

    TInt iId;

    // State of session, owned

    TUpnpTcpSessionState iState;

    // ETrue, if session is meant to be kept alive; EFalse otherwise, owned

    TBool iSessionKeepAlive;

    // ETrue, if session needs 408 HTTP error on timeout, owned

    TBool iSessionNeedsErrorReply;

    // Used with session disconnects. If ETrue, session send notification 

    // of disconnect to upper layers, owned

    TBool iDisconnectNotification;

    //Flag set true if any pending requests are left in a pipeline awating to be proccessed

    TBool iPendingPostRequests;

    // value that is used to check if downloaded content should be saved 

    // into a file.

    TBool iSaveToFile;

    // The current value of timeout, changes dependent on a operation-connecting, sending,...

    TInt iTimeoutCurrentValue;

    // Timeout that defines the session length

    TInt iTimeoutSessionValue;

    // Flag indicating if POST message with header "Expect: 100-continue"

    // was received and server should wait for download of body after

    // sending permission to continue download.

    TBool iContinuedMessageDownload;

    // Initial priority, priority set for message that initialize this session

    TThreadPriority iInitialPriority;

    //flag for indicating a persistant connection

    TBool iIsPersistent;

    // Implementation of the socket shutdown algorithm

    CUpnpSocketShutdown *iSocketShutdown;

    // Retry counter during export action

    TInt iExportRetryCounter;

    TInt iSessionError;

    };