www.pudn.com > sockets.rar > socketswriter.h

/* Copyright (c) 2004, Nokia. All rights reserved */ 
 
 
#ifndef __SOCKETSWRITER_H__ 
#define __SOCKETSWRITER_H__ 
 
// INCLUDES 
#include  
#include "TimeOutNotifier.h" 
 
// FORWARD DECLARATIONS 
class CTimeOutTimer; 
class MEngineNotifier; 
 
// CLASS DECLARATION 
/** 
* CSocketsWriter 
*  This class handles writing data to the socket. 
*  Data to be written is accumulated in iTransferBuffer, 
*  and is then transferred to iWriteBuffer for the actual 
*  write to the socket. 
*/ 
class CSocketsWriter : public CActive, public MTimeOutNotifier 
    { 
    public: // Constructors and destructors 
 
        /** 
        * NewL. 
        * Two-phased constructor. 
        * Creates a CSocketsWriter object using two phase construction, 
        * and returns a pointer to the created object. 
        * @param aEngineNotifier An observer for status reporting. 
        * @param aSocket Socket to write to. 
        * @return A pointer to the created instance of CSocketsWriter. 
        */ 
        static CSocketsWriter* NewL( MEngineNotifier& aEngineNotifier, 
                                     RSocket& aSocket ); 
 
        /** 
        * NewLC. 
        * Two-phased constructor. 
        * Creates a CSocketsWriter object using two phase construction, 
        * and returns a pointer to the created object. 
        * @param aEngineNotifier An observer for status reporting. 
        * @param aSocket Socket to write to. 
        * @return A pointer to the created instance of CSocketsWriter. 
        */ 
        static CSocketsWriter* NewLC( MEngineNotifier& aEngineNotifier, 
                                      RSocket& aSocket ); 
 
        /** 
        * ~CSocketsWriter. 
        * Destructor. 
        * Destroys the object and release all memory objects. 
        */ 
        virtual ~CSocketsWriter(); 
 
    public: // New functions 
 
        /** 
        * IssueWrite. 
        * Writes the data to the socket ( buffered ). 
        * @param aData The data to be written. 
        */ 
        void IssueWriteL( const TDesC8& aData ); 
 
    public: // Functions from base classes 
 
        /** 
        * From MTimeOutNotifier, TimerExpired. 
        * Handles a timeout event. 
        */ 
        void TimerExpired(); 
 
    protected: // Functions from base classes 
 
        /** 
        * From CActive, DoCancel. 
        * Cancels any outstanding operation. 
        */ 
        void DoCancel(); 
 
        /** 
        * From CActive, RunL. 
        * Called when operation completes. 
        */ 
        void RunL(); 
 
    private: // Constructors and destructors 
 
        /** 
        * CSocketsWriter. 
        * C++ default constructor. 
        * Performs the first phase of two phase construction. 
        * @param aEngineNotifier An observer for status reporting. 
        * @param aSocket Socket to write to. 
        */ 
        CSocketsWriter( MEngineNotifier& aEngineNotifier, RSocket& aSocket ); 
 
        /** 
        * ConstructL. 
        * 2nd phase constructor. 
        */ 
        void ConstructL(); 
 
    private: // New functions 
 
        /** 
        * SendNextPacket. 
        * Handles a 'write buffer empty' situation. 
        */ 
        void SendNextPacket(); 
 
    private: // Constants 
 
        /** 
        * KWriteBufferSize, the size of the write buffer in bytes. 
        */ 
        enum { KWriteBufferSize = 20 }; 
 
        /** 
        * KTimeOut, the maximum time allowed for a write to complete. 
        */ 
        static const TInt KTimeOut; 
 
    private: // Enumerations 
 
        /** 
        * TWriteState, records whether a write request is pending. 
        *   - ESending  A write request is pending with the socket server. 
        *   - EWaiting  The idle state for this object. 
        * 
        */ 
        enum TWriteState 
            { 
            ESending, 
            EWaiting 
            }; 
 
    private: // Data 
 
        /** 
        * iSocket, the socket to write to. 
        */ 
        RSocket& iSocket; 
 
        /** 
        * iEngineNotifier, an observer for status reporting. 
        */ 
        MEngineNotifier& iEngineNotifier; 
 
        /** 
        * iTransferBuffer, accumulate data to send in here. 
        */ 
        TBuf8 iTransferBuffer; 
 
        /** 
        * iWriteBuffer, holds data currently being sent to socket. 
        */ 
        TBuf8 iWriteBuffer; 
 
        /** 
        * iTimer, a timer used to cancel an outstanding write 
        *         after a predefined timeout. 
        * Owned by CSocketsWriter object. 
        */ 
        CTimeOutTimer* iTimer; 
 
        /** 
        * iTimeOut, the timeout to use. 
        */ 
        TInt iTimeOut; 
 
        /** 
        * iWriteStatus, the state of this active object. 
        */ 
        TWriteState iWriteStatus; 
    }; 
 
#endif // __SOCKETSWRITER_H__ 
 
// End of File