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// -*- c++ -*-
//------------------------------------------------------------------------------
//                           PidFileLock.h
//------------------------------------------------------------------------------
// $Id: PidFileLock.h,v 1.7 2006/07/20 02:30:54 vlg Exp $
//------------------------------------------------------------------------------
//  Copyright (C) 1997-2002,2005  Vladislav Grinchenko
//
//  This library is free software; you can redistribute it and/or
//  modify it under the terms of the GNU Library General Public
//  License as published by the Free Software Foundation; either
//  version 2 of the License, or (at your option) any later version.
//------------------------------------------------------------------------------
#ifndef FILE_LOCK_H
#define FILE_LOCK_H

//System Includes
#include <sys/types.h>

#include "assa/Assure.h"

//STL
#include <string>
using std::string;

#if defined(WIN32)
struct flock {
       off_t l_start;
       off_t l_len;
       pid_t l_pid;
       short l_type;
       short l_whence;
};
#endif

namespace ASSA {

class PidFileLock   : public flock
{
public:
    PidFileLock ();

    ~PidFileLock ();

    bool lock (const string& filename_);

    int get_error () const;
    
    const char* get_error_msg () const;

    void dump ();

private:
    pid_t open_pid_file (const std::string& fname_);

    int lock_region ();

    int lock_region_exclusive ();

    int unlock_region ();

    int get_lock_status ();


    int write_pid ();

    pid_t test_region ();

    void log_error   (const char* msg_);

private:
    string m_filename;

    int    m_fd;

    int    m_error;

    string m_error_msg;
};

inline int 
PidFileLock::
get_error () const 
{ 
    return m_error; 
}

inline const char* 
PidFileLock::
get_error_msg () const 
{ 
    return m_error_msg.c_str (); 
}

} // end namespace ASSA

#endif /* FILE_LOCK_H */  

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