SYS_Handle.h

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/*
 * PROPRIETARY INFORMATION.  This software is proprietary to
 * Side Effects Software Inc., and is not to be reproduced,
 * transmitted, or disclosed in any way without written permission.
 *
 * NAME:        SYS_Handle.h (SYS Library, C++)
 *
 * COMMENTS:    Platform independent handle for marshalling between Unix file
 *              descriptors (int) and Windows HANDLE objects (which are assumed
 *              to be void *).
 */

#ifndef __SYS_HANDLE_H_INCLUDED__
#define __SYS_HANDLE_H_INCLUDED__

#include "SYS_API.h"


typedef void *              SYS_WinHandle;
typedef int                 SYS_UnixHandle;

// We assume that sizeof(SYS_WinHandle) > sizeof(UnixHandle) so we use that as
// the invalid value.
#define SYS_INVALID_HANDLE  SYS_WinHandle(-1)


union SYS_API SYS_Handle
{
public:
                            SYS_Handle()
                                : myWinHandle(SYS_INVALID_HANDLE)
                            {
                            }
                            explicit
                            SYS_Handle(SYS_UnixHandle h)
                                : myWinHandle(SYS_INVALID_HANDLE)
                            {
                                myUnixHandle = h;
                                if (h < 0)
                                    invalidate();
                            }
                            explicit
                            SYS_Handle(SYS_WinHandle h)
                                : myWinHandle(h)
                            {
                            }

    void                    invalidate()
                                { myWinHandle = SYS_INVALID_HANDLE; }
    bool                    isValid() const
                                { return (myWinHandle != SYS_INVALID_HANDLE); }

    SYS_UnixHandle          unixHandle() const
                                { return myUnixHandle; }
    void                    setUnixHandle(SYS_UnixHandle h)
                                { myUnixHandle = h; }

    SYS_WinHandle           winHandle() const
                                { return myWinHandle; }
    void                    setWinHandle(SYS_WinHandle h)
                                { myWinHandle = h; }

private:
    SYS_WinHandle           myWinHandle;
    SYS_UnixHandle          myUnixHandle;
};

/// Closes the file if it's valid and invalidates it.
SYS_API void SYShandleClose(SYS_Handle& handle);

#endif // __SYS_HANDLE_H_INCLUDED__