OW_PosixFile.cpp

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#include "OW_config.h"
#include "OW_File.hpp"

#ifdef OW_WIN32
   #include <io.h>
   #include <stdlib.h>
   #include <stdio.h>
   #include <memory.h>
#else
   #include <fcntl.h>
   #ifdef OW_HAVE_UNISTD_H
      #include <unistd.h>
   #endif
#endif


namespace OW_NAMESPACE
{
#ifdef OW_WIN32
namespace
{
// implementation of lock functions
int
doLock(HANDLE hFile, bool doWait)
{
   if (hFile == INVALID_HANDLE_VALUE)
   {
      return -1;
   }

   DWORD flags = LOCKFILE_EXCLUSIVE_LOCK;
   if (!doWait)
   {
      flags |= LOCKFILE_FAIL_IMMEDIATELY;
   }

   OVERLAPPED ov;
   memset(&ov, 0, sizeof(ov));
   if (!LockFileEx(hFile, flags, 0, 0xffffffff,
      0xffffffff, &ov))
   {
      return -1;
   }

   return 0;
}

} // end unnamed namespace

File::File(const File& x) : m_hdl(OW_INVALID_FILEHANDLE)
{
   if( x.m_hdl != OW_INVALID_FILEHANDLE )
   {
      DuplicateHandle(GetCurrentProcess(), x.m_hdl, GetCurrentProcess(),
         &m_hdl , 0, FALSE, DUPLICATE_SAME_ACCESS);
   }
}
int 
File::getLock()
{
   return doLock(m_hdl, true);
}
int
File::tryLock()
{
   return doLock(m_hdl, false);
}
int
File::unlock()
{
   if (m_hdl == INVALID_HANDLE_VALUE)
   {
      return -1;
   }

   OVERLAPPED ov;
   memset(&ov, 0, sizeof(ov));
   if (!UnlockFileEx(m_hdl, 0, 0xffffffff, 0xffffffff, &ov))
   {
      return -1;
   }

   return 0;
}

#else // NOT WIN32

File::File(const File& x) : m_hdl(dup(x.m_hdl))
{
}

namespace {
// implementation of lock functions
int
doLock(int hdl, int cmd, short int type)
{
   struct flock lck;
   ::memset (&lck, '\0', sizeof (lck));
   lck.l_type = type;          // type of lock
   lck.l_whence = 0;           // 0 offset for l_start
   lck.l_start = 0L;           // lock starts at BOF
   lck.l_len = 0L;             // extent is entire file
   return ::fcntl(hdl, cmd, &lck);
}
} // end unnamed namespace
int 
File::getLock()
{
   return doLock(m_hdl, F_SETLKW, F_WRLCK);
}
int
File::tryLock()
{
   return doLock(m_hdl, F_SETLK, F_WRLCK);
}
int
File::unlock()
{
   return doLock(m_hdl, F_SETLK, F_UNLCK);
}
#endif

} // end namespace OW_NAMESPACE

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