private PagerState CreatePagerState()
{
var startingBaseAddressPtr = Syscall.mmap(IntPtr.Zero, (ulong)_totalAllocationSize,
MmapProts.PROT_READ | MmapProts.PROT_WRITE,
MmapFlags.MAP_SHARED, _fd, 0);
if (startingBaseAddressPtr.ToInt64() == -1) //system didn't succeed in mapping the address where we wanted
PosixHelper.ThrowLastError(Marshal.GetLastWin32Error());
var allocationInfo = new PagerState.AllocationInfo
{
BaseAddress = (byte*)startingBaseAddressPtr.ToPointer(),
Size = _totalAllocationSize,
MappedFile = null
};
var newPager = new PagerState(this)
{
Files = null, // unused
MapBase = allocationInfo.BaseAddress,
AllocationInfos = new[] { allocationInfo }
};
newPager.AddRef(); // one for the pager
return newPager;
}
private PagerState CreatePagerState()
{
var mmf = MemoryMappedFile.CreateFromFile(_fileStream, null, _fileStream.Length,
_memoryMappedFileAccess,
null, HandleInheritability.None, true);
var fileMappingHandle = mmf.SafeMemoryMappedFileHandle.DangerousGetHandle();
var mmFileAccessType = _access == Win32NativeFileAccess.GenericRead
? Win32MemoryMapNativeMethods.NativeFileMapAccessType.Read
: Win32MemoryMapNativeMethods.NativeFileMapAccessType.Read | Win32MemoryMapNativeMethods.NativeFileMapAccessType.Write;
var startingBaseAddressPtr = Win32MemoryMapNativeMethods.MapViewOfFileEx(fileMappingHandle,
mmFileAccessType,
0, 0,
UIntPtr.Zero, //map all what was "reserved" in CreateFileMapping on previous row
null);
if (startingBaseAddressPtr == (byte*)0) //system didn't succeed in mapping the address where we wanted
throw new Win32Exception();
var allocationInfo = new PagerState.AllocationInfo
{
BaseAddress = startingBaseAddressPtr,
Size = _fileStream.Length,
MappedFile = mmf
};
var newPager = new PagerState(this)
{
Files = new[] { mmf },
MapBase = startingBaseAddressPtr,
AllocationInfos = new[] { allocationInfo }
};
newPager.AddRef(); // one for the pager
return newPager;
}
private PagerState CreateInitialPagerState(long size)
{
var allocationSize = NearestSizeToAllocationGranularity(size);
var mmf = MemoryMappedFile.CreateNew(null, allocationSize, MemoryMappedFileAccess.ReadWrite);
var fileMappingHandle = mmf.SafeMemoryMappedFileHandle.DangerousGetHandle();
var startingBaseAddressPtr = Win32MemoryMapNativeMethods.MapViewOfFileEx(fileMappingHandle,
Win32MemoryMapNativeMethods.NativeFileMapAccessType.Read |
Win32MemoryMapNativeMethods.NativeFileMapAccessType.Write,
0, 0,
UIntPtr.Zero, //map all what was "reserved" in CreateFileMapping on previous row
null);
if (startingBaseAddressPtr == (byte*)0) //system didn't succeed in mapping the address where we wanted
throw new Win32Exception();
var allocationInfo = new PagerState.AllocationInfo
{
BaseAddress = startingBaseAddressPtr,
Size = allocationSize,
MappedFile = mmf
};
var newPager = new PagerState(this)
{
Files = new[] { mmf },
MapBase = startingBaseAddressPtr,
AllocationInfos = new[] { allocationInfo }
};
newPager.AddRef();
return newPager;
}
