/// <exception cref="IOException">IO error while mapping memory or not enough memory to create the mapping.</exception>
private unsafe bool TryCreateMemoryMappedFileBlock(long start, int size, [NotNullWhen(true)] out MemoryMappedFileBlock?block)
{
if (_lazyMemoryMap == null)
{
// leave the underlying stream open. It will be closed by the Dispose method.
MemoryMappedFile newMemoryMap;
// CreateMemoryMap might modify the stream (calls FileStream.Flush)
lock (_streamGuard)
{
try
{
newMemoryMap =
MemoryMappedFile.CreateFromFile(
fileStream: (FileStream)_stream,
mapName: null,
capacity: 0,
access: MemoryMappedFileAccess.Read,
inheritability: HandleInheritability.None,
leaveOpen: true);
} catch (UnauthorizedAccessException e)
{
throw new IOException(e.Message, e);
}
}
if (newMemoryMap == null)
{
block = null;
return(false);
}
if (Interlocked.CompareExchange(ref _lazyMemoryMap, newMemoryMap, null) != null)
{
newMemoryMap.Dispose();
}
}
MemoryMappedViewAccessor accessor;
lock (_streamGuard)
{
accessor = _lazyMemoryMap.CreateViewAccessor(start, size, MemoryMappedFileAccess.Read);
}
if (accessor == null)
{
block = null;
return(false);
}
block = new MemoryMappedFileBlock(accessor, accessor.SafeMemoryMappedViewHandle, accessor.PointerOffset, size);
return(true);
}
private unsafe bool TryCreateMemoryMappedFileBlock(long start, int size, out MemoryMappedFileBlock block)
{
if (_lazyMemoryMap == null)
{
// leave the underlying stream open. It will be closed by the Dispose method.
IDisposable newMemoryMap;
// CreateMemoryMap might modify the stream (calls FileStream.Flush)
lock (_streamGuard)
{
newMemoryMap = MemoryMapLightUp.CreateMemoryMap(_stream);
}
if (newMemoryMap == null)
{
block = null;
return(false);
}
if (Interlocked.CompareExchange(ref _lazyMemoryMap, newMemoryMap, null) != null)
{
newMemoryMap.Dispose();
}
}
IDisposable accessor = MemoryMapLightUp.CreateViewAccessor(_lazyMemoryMap, start, size);
if (accessor == null)
{
block = null;
return(false);
}
SafeBuffer safeBuffer;
byte * pointer = MemoryMapLightUp.AcquirePointer(accessor, out safeBuffer);
if (pointer == null)
{
block = null;
return(false);
}
block = new MemoryMappedFileBlock(accessor, safeBuffer, pointer, size);
return(true);
}
/// <exception cref="IOException">IO error while mapping memory or not enough memory to create the mapping.</exception>
private unsafe bool TryCreateMemoryMappedFileBlock(long start, int size, [NotNullWhen(true)] out MemoryMappedFileBlock?block)
{
if (_lazyMemoryMap == null)
{
// leave the underlying stream open. It will be closed by the Dispose method.
IDisposable newMemoryMap;
// CreateMemoryMap might modify the stream (calls FileStream.Flush)
lock (_streamGuard)
{
newMemoryMap = MemoryMapLightUp.CreateMemoryMap(_stream);
}
if (newMemoryMap == null)
{
block = null;
return(false);
}
if (Interlocked.CompareExchange(ref _lazyMemoryMap, newMemoryMap, null) != null)
{
newMemoryMap.Dispose();
}
}
IDisposable accessor = MemoryMapLightUp.CreateViewAccessor(_lazyMemoryMap, start, size);
if (accessor == null)
{
block = null;
return(false);
}
if (!MemoryMapLightUp.TryGetSafeBufferAndPointerOffset(accessor, out var safeBuffer, out long offset))
{
block = null;
return(false);
}
block = new MemoryMappedFileBlock(accessor, safeBuffer, offset, size);
return(true);
}
private unsafe bool TryCreateMemoryMappedFileBlock(long start, int size, out MemoryMappedFileBlock block)
{
if (_lazyMemoryMap == null)
{
// leave the underlying stream open. It will be closed by the Dispose method.
IDisposable newMemoryMap;
// CreateMemoryMap might modify the stream (calls FileStream.Flush)
lock (_streamGuard)
{
newMemoryMap = MemoryMapLightUp.CreateMemoryMap(_stream);
}
if (newMemoryMap == null)
{
block = null;
return false;
}
if (Interlocked.CompareExchange(ref _lazyMemoryMap, newMemoryMap, null) != null)
{
newMemoryMap.Dispose();
}
}
IDisposable accessor = MemoryMapLightUp.CreateViewAccessor(_lazyMemoryMap, start, size);
if (accessor == null)
{
block = null;
return false;
}
SafeBuffer safeBuffer;
byte* pointer = MemoryMapLightUp.AcquirePointer(accessor, out safeBuffer);
if (pointer == null)
{
block = null;
return false;
}
block = new MemoryMappedFileBlock(accessor, safeBuffer, pointer, size);
return true;
}