indchan.h

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/*
 * indchan.h
 *
 * Indirect I/O channel class.
 *
 * Portable Windows Library
 *
 * Copyright (c) 1993-1998 Equivalence Pty. Ltd.
 *
 * The contents of this file are subject to the Mozilla Public License
 * Version 1.0 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS"
 * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
 * the License for the specific language governing rights and limitations
 * under the License.
 *
 * The Original Code is Portable Windows Library.
 *
 * The Initial Developer of the Original Code is Equivalence Pty. Ltd.
 *
 * Portions are Copyright (C) 1993 Free Software Foundation, Inc.
 * All Rights Reserved.
 *
 * Contributor(s): ______________________________________.
 *
 * $Log: indchan.h,v $
 * Revision 1.11  2006/06/21 03:28:41  csoutheren
 * Various cleanups thanks for Frederic Heem
 *
 * Revision 1.10  2005/11/25 03:43:47  csoutheren
 * Fixed function argument comments to be compatible with Doxygen
 *
 * Revision 1.9  2002/09/16 01:08:59  robertj
 * Added #define so can select if #pragma interface/implementation is used on
 *   platform basis (eg MacOS) rather than compiler, thanks Robert Monaghan.
 *
 * Revision 1.8  2001/09/10 02:51:22  robertj
 * Major change to fix problem with error codes being corrupted in a
 *   PChannel when have simultaneous reads and writes in threads.
 *
 * Revision 1.7  2001/05/22 12:49:32  robertj
 * Did some seriously wierd rewrite of platform headers to eliminate the
 *   stupid GNU compiler warning about braces not matching.
 *
 * Revision 1.6  2000/11/14 08:25:25  robertj
 * Added function to propagate the error text through to indirect channel.
 *
 * Revision 1.5  1999/06/17 13:38:11  robertj
 * Fixed race condition on indirect channel close, mutex needed in PIndirectChannel.
 *
 * Revision 1.4  1999/03/09 02:59:49  robertj
 * Changed comments to doc++ compatible documentation.
 *
 * Revision 1.3  1999/02/16 08:12:00  robertj
 * MSVC 6.0 compatibility changes.
 *
 * Revision 1.2  1998/09/23 06:20:41  robertj
 * Added open source copyright license.
 *
 * Revision 1.1  1996/09/14 13:00:56  robertj
 * Initial revision
 *
 */

#ifndef _PINDIRECTCHANNEL
#define _PINDIRECTCHANNEL

#ifdef P_USE_PRAGMA
#pragma interface
#endif

#include <ptlib/channel.h>


class PIndirectChannel : public PChannel
{
  PCLASSINFO(PIndirectChannel, PChannel);

  public:
    PIndirectChannel();

    ~PIndirectChannel();


    Comparison Compare(
      const PObject & obj   
    ) const;


    virtual PString GetName() const;

    virtual BOOL Close();

    virtual BOOL IsOpen() const;

    virtual BOOL Read(
      void * buf,   
      PINDEX len    
    );

    virtual BOOL Write(
      const void * buf, 
      PINDEX len        
    );

    virtual BOOL Shutdown(
      ShutdownValue option   
    );


    virtual PChannel * GetBaseReadChannel() const;

    virtual PChannel * GetBaseWriteChannel() const;

    virtual PString GetErrorText(
      ErrorGroup group = NumErrorGroups   
    ) const;

    BOOL Open(
      PChannel & channel   
    );

    BOOL Open(
      PChannel * channel,      
      BOOL autoDelete = TRUE   
    );

    BOOL Open(
      PChannel * readChannel,      
      PChannel * writeChannel,     
      BOOL autoDeleteRead = TRUE,  
      BOOL autoDeleteWrite = TRUE  
    );

    PChannel * GetReadChannel() const;

    BOOL SetReadChannel(
      PChannel * channel,      
      BOOL autoDelete = TRUE   
    );

    PChannel * GetWriteChannel() const;

    BOOL SetWriteChannel(
      PChannel * channel,      
      BOOL autoDelete = TRUE   
    );


  protected:
    virtual BOOL OnOpen();


  // Member variables
    PChannel * readChannel;

    BOOL readAutoDelete;

    PChannel * writeChannel;

    BOOL writeAutoDelete;

    PReadWriteMutex channelPointerMutex;
};


#endif // _PINDIRECTCHANNEL


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