public BackupStreamInfo ReadStreamInfo()
{
using (SafeGlobalMemoryBufferHandle hBuf = new SafeGlobalMemoryBufferHandle(Marshal.SizeOf(typeof(NativeMethods.WIN32_STREAM_ID))))
{
uint numberOfBytesRead;
if (!NativeMethods.BackupRead(_safeFileHandle, hBuf, (uint)Marshal.SizeOf(typeof(NativeMethods.WIN32_STREAM_ID)), out numberOfBytesRead, false, mProcessSecurity, ref m_context))
{
NativeError.ThrowException();
}
if (numberOfBytesRead == 0)
{
return(null);
}
if (numberOfBytesRead < Marshal.SizeOf(typeof(NativeMethods.WIN32_STREAM_ID)))
{
throw new IOException(Resources.IncompleteHeaderRead);
}
NativeMethods.WIN32_STREAM_ID streamID = hBuf.PtrToStructure <NativeMethods.WIN32_STREAM_ID>();
uint nameLength = (uint)Math.Min(streamID.StreamNameSize, hBuf.Capacity);
if (!NativeMethods.BackupRead(_safeFileHandle, hBuf, nameLength, out numberOfBytesRead, false, mProcessSecurity, ref m_context))
{
NativeError.ThrowException();
}
string name = hBuf.PtrToStringUni((int)nameLength / 2);
return(new BackupStreamInfo(streamID, name));
}
}
/// <summary>
/// Initializes a new instance of the <see cref="BackupStreamInfo"/> class.
/// </summary>
/// <param name="streamID">The stream ID.</param>
/// <param name="name">The name.</param>
internal BackupStreamInfo(NativeMethods.WIN32_STREAM_ID streamID, string name)
{
mSize = (long)streamID.Size;
mName = name;
mAttributes = (StreamAttributes)streamID.dwStreamAttributes;
mStreamType = (BackupStreamType)streamID.dwStreamId;
}