private FileObject.FileMemoryStream OpenStreamInternal(AbsolutePath path, FileAccess accessMode, FileMode mode, FileShare share)
{
if (mode == FileMode.CreateNew && accessMode == FileAccess.Read)
{
throw new ArgumentException("FileMode.CreateNew and FileAccess.Read is an invalid combination.");
}
lock (_drives)
{
FileObject fileObj = FindFileObjectAndParent(path, out var parent);
if (parent == null)
{
return(null);
}
switch (mode)
{
case FileMode.Create:
if (fileObj != null)
{
fileObj.DeleteLink(path, false);
parent.Children.Remove(path.FileName);
}
fileObj = new FileObject(path, this, new byte[] {});
parent.Children[path.FileName] = fileObj;
break;
case FileMode.Open:
if (fileObj == null)
{
return(null);
}
break;
case FileMode.OpenOrCreate:
if (fileObj == null)
{
fileObj = new FileObject(path, this, new byte[] {});
parent.Children[path.FileName] = fileObj;
}
break;
case FileMode.CreateNew:
if (fileObj != null)
{
unchecked
{
throw new IOException("File already exists", new IOException("File exists", (int)Hresult.FileExists));
}
}
fileObj = new FileObject(path, this, new byte[] {});
parent.Children[path.FileName] = fileObj;
break;
default:
throw new NotImplementedException($"Mode '{mode}' is not supported.");
}
var file = fileObj.Open(path, accessMode, share);
if (accessMode.HasFlag(FileAccess.Write))
{
_currentStatistics.FileOpensForWrite++;
}
else
{
_currentStatistics.FileOpensForRead++;
}
return(file);
}
}
