public VirtualFileOpenStream([NotNull] VirtualDiskImpl disk, [NotNull] IFileBlock file)
{
if (file == null)
throw new ArgumentNullException("file");
if (disk == null)
throw new ArgumentNullException("disk");
_disk = disk;
_file = file;
_currentFileBlock = _file;
_bytesRead = 0;
// Make sure the buffer starts out initialized
_moveToNextContinuationBlock();
}
/// <summary>
/// Copies the data block offsets of the <see cref="_currentFileBlock"/> to the <see cref="_offsetBuffer"/>. Signals if there are potentially more continuation blocks.
/// </summary>
/// <returns>True if it makes sense to call the method again; false otherwise</returns>
private bool _moveToNextContinuationBlock()
{
// It must be safe to call this method, even if it has returned false before.
if (_currentFileBlock == null)
return false;
// Read the entire offset list into our buffer
foreach (var dataBlockOffset in _currentFileBlock)
_offsetBuffer.Enqueue(dataBlockOffset);
// See if it makes sense to have _moveNext called again
if (_currentFileBlock.ContinuationBlockOffset != null)
{
_currentFileBlock = _disk.BlockManager.GetFileContinuationBlock(_currentFileBlock.ContinuationBlockOffset.Value);
}
else
{
_currentFileBlock = null;
}
return true;
}
