/*
   Copyright (C) 2003-2006, 2008 MySQL AB, 2008 Sun Microsystems, Inc.
    All rights reserved. Use is subject to license terms.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License, version 2.0,
   as published by the Free Software Foundation.

   This program is also distributed with certain software (including
   but not limited to OpenSSL) that is licensed under separate terms,
   as designated in a particular file or component or in included license
   documentation.  The authors of MySQL hereby grant you an additional
   permission to link the program and your derivative works with the
   separately licensed software that they have included with MySQL.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License, version 2.0, for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA
*/

#ifndef SHM_Transporter_H
#define SHM_Transporter_H

#include "Transporter.hpp"
#include "SHM_Buffer.hpp"

#ifdef NDB_WIN32
typedef Uint32 key_t;
#endif

/** 
 * class SHMTransporter
 * @brief - main class for the SHM transporter.
 */

class SHM_Transporter : public Transporter {
  friend class TransporterRegistry;
public:
  SHM_Transporter(TransporterRegistry &,
		  const char *lHostName,
		  const char *rHostName, 
		  int r_port,
		  bool isMgmConnection,
		  NodeId lNodeId,
		  NodeId rNodeId,
		  NodeId serverNodeId,
		  bool checksum, 
		  bool signalId,
		  key_t shmKey,
		  Uint32 shmSize);
  
  /**
   * SHM destructor
   */
  virtual ~SHM_Transporter();
  
  virtual bool configure_derived(const TransporterConfiguration* conf);

  /**
   * Do initialization
   */
  bool initTransporter();
  
  void getReceivePtr(Uint32 ** ptr, Uint32 ** eod){
    reader->getReadPtr(* ptr, * eod);
  }
  
  void updateReceivePtr(Uint32 * ptr){
    reader->updateReadPtr(ptr);
  }
  
protected:
  /**
   * disconnect a segmnet
   * -# deletes the shm buffer associated with a segment
   * -# marks the segment for removal
   */
  void disconnectImpl();

  /**
   * Blocking
   *
   * -# Create shm segment
   * -# Attach to it
   * -# Wait for someone to attach (max wait = timeout), then rerun again
   *    until connection established.
   * @param timeOutMillis - the time to sleep before (ms) trying again.
   * @returns - True if the server managed to hook up with the client,
   *            i.e., both agrees that the other one has setup the segment.
   *            Otherwise false.
   */
  virtual bool connect_server_impl(NDB_SOCKET_TYPE sockfd);

  /**
   * Blocking
   *
   * -# Attach to shm segment
   * -# Check if the segment is setup
   * -# Check if the server set it up
   * -# If all clear, return.
   * @param timeOutMillis - the time to sleep before (ms) trying again.
   * @returns - True if the client managed to hook up with the server,
   *            i.e., both agrees that the other one has setup the segment.
   *            Otherwise false.
   */
  virtual bool connect_client_impl(NDB_SOCKET_TYPE sockfd);

  bool connect_common(NDB_SOCKET_TYPE sockfd);

  bool ndb_shm_create();
  bool ndb_shm_get();
  bool ndb_shm_attach();

  /**
   * Check if there are two processes attached to the segment (a connection)
   * @return - True if the above holds. Otherwise false.
   */
  bool checkConnected();

  
  /**
   * Initialises the SHM_Reader and SHM_Writer on the segment 
   */
  void setupBuffers();

  /**
   * doSend (i.e signal receiver)
   */
  int doSend();
  int m_remote_pid;
  Uint32 m_signal_threshold;

private:
  bool _shmSegCreated;
  bool _attached;
  bool m_connected;
  
  key_t shmKey;
  volatile Uint32 * serverStatusFlag;
  volatile Uint32 * clientStatusFlag;  
  bool setupBuffersDone;
  
#ifdef NDB_WIN32
  HANDLE hFileMapping;
#else
  int shmId;
#endif
  
  int shmSize;
  char * shmBuf;
  
  SHM_Reader * reader;
  SHM_Writer * writer;
  
  /**
   * @return - True if the reader has data to read on its segment.
   */
  bool hasDataToRead() const {
    return reader->empty() == false;
  }

  void make_error_info(char info[], int sz);

  bool send_limit_reached(int bufsize)
  {
    return ((Uint32)bufsize >= m_signal_threshold);
  }
  bool send_is_possible(int timeout_millisec) const { return 1; }
};

#endif