/// <summary>Initializes a new instance of the <see cref="T:AlternateDataStreamInfo"/> class.</summary>
/// <param name="stream">The <see cref="T:NativeMethods.Win32StreamId"/> stream ID.</param>
/// <param name="transaction"></param>
/// <param name="path">The path to an existing file or directory.</param>
/// <param name="name">The originalName of the stream.</param>
/// <param name="originalName">The alternative data stream name originally specified by the user.</param>
/// <param name="isFolder">Specifies that <paramref name="path"/> is a file or directory. <c>null</c> to retrieve automatically.</param>
/// <param name="isFullPath">
/// <para><c>true</c> <paramref name="path"/> is an absolute path. Unicode prefix is applied.</para>
/// <para><c>false</c> <paramref name="path"/> will be checked and resolved to an absolute path. Unicode prefix is applied.</para>
/// <para><c>null</c> <paramref name="path"/> is already an absolute path with Unicode prefix. Use as is.</para>
/// </param>
private AlternateDataStreamInfo(NativeMethods.Win32StreamId stream, KernelTransaction transaction, string path, string name, string originalName, bool?isFolder, bool?isFullPath)
{
if (Utils.IsNullOrWhiteSpace(path))
{
throw new ArgumentNullException("path");
}
_isFullPath = isFullPath;
Transaction = transaction;
OriginalName = originalName;
Name = name ?? string.Empty;
Attributes = stream.StreamAttributes;
Type = stream.StreamType;
Size = (long)stream.StreamSize;
FullName = path + Name;
if (isFolder == null)
{
FileAttributes attrs = File.GetAttributesExInternal <FileAttributes>(transaction, LongFullName, null);
IsDirectory = (attrs & FileAttributes.Directory) == FileAttributes.Directory;
}
else
{
IsDirectory = (bool)isFolder;
}
}
internal static IEnumerable <AlternateDataStreamInfo> EnumerateStreamsInternal(bool?isFolder, KernelTransaction transaction, SafeFileHandle safeHandle, string path, string originalName, StreamType?streamType, bool?isFullPath)
{
string pathLp = null;
bool callerHandle = safeHandle != null;
if (!callerHandle)
{
pathLp = isFullPath == null
? path
: (bool)isFullPath
? Path.GetLongPathInternal(path, false, false, false, false)
: Path.GetFullPathInternal(transaction, path, true, false, false, true, false, true, false);
if (isFolder == null)
{
FileAttributes attrs = File.GetAttributesExInternal <FileAttributes>(transaction, pathLp, null);
isFolder = (attrs & FileAttributes.Directory) == FileAttributes.Directory;
}
safeHandle = File.CreateFileInternal(transaction, pathLp,
(bool)isFolder
? ExtendedFileAttributes.BackupSemantics
: ExtendedFileAttributes.Normal, null,
FileMode.Open, FileSystemRights.Read, FileShare.ReadWrite, false, null);
}
else
{
NativeMethods.IsValidHandle(safeHandle);
}
try
{
using (new PrivilegeEnabler(Privilege.Backup))
using (SafeGlobalMemoryBufferHandle safeBuffer = new SafeGlobalMemoryBufferHandle(NativeMethods.DefaultFileBufferSize))
{
Type typeWin32Stream = typeof(NativeMethods.Win32StreamId);
uint sizeOfType = (uint)Marshal.SizeOf(typeWin32Stream);
uint numberOfBytesRead;
IntPtr context;
bool doLoop = true;
while (doLoop)
{
if (!NativeMethods.BackupRead(safeHandle, safeBuffer, sizeOfType, out numberOfBytesRead, false, true, out context))
{
// Throws IOException.
NativeError.ThrowException(Marshal.GetLastWin32Error(), pathLp, true);
}
doLoop = numberOfBytesRead == sizeOfType;
if (doLoop)
{
string streamName = null;
string streamSearchName = null;
// CA2001:AvoidCallingProblematicMethods
IntPtr buffer = IntPtr.Zero;
bool successRef = false;
safeBuffer.DangerousAddRef(ref successRef);
// MSDN: The DangerousGetHandle method poses a security risk because it can return a handle that is not valid.
if (successRef)
{
buffer = safeBuffer.DangerousGetHandle();
}
safeBuffer.DangerousRelease();
if (buffer == IntPtr.Zero)
{
NativeError.ThrowException(Resources.HandleDangerousRef);
}
// CA2001:AvoidCallingProblematicMethods
NativeMethods.Win32StreamId stream = Utils.MarshalPtrToStructure <NativeMethods.Win32StreamId>(0, buffer);
if (streamType == null || stream.StreamType == streamType)
{
if (stream.StreamNameSize > 0)
{
if (!NativeMethods.BackupRead(safeHandle, safeBuffer, stream.StreamNameSize, out numberOfBytesRead, false, true, out context))
{
// Throws IOException.
NativeError.ThrowException(Marshal.GetLastWin32Error(), pathLp, true);
}
// CA2001:AvoidCallingProblematicMethods
buffer = IntPtr.Zero;
successRef = false;
safeBuffer.DangerousAddRef(ref successRef);
// MSDN: The DangerousGetHandle method poses a security risk because it can return a handle that is not valid.
if (successRef)
{
buffer = safeBuffer.DangerousGetHandle();
}
safeBuffer.DangerousRelease();
if (buffer == IntPtr.Zero)
{
NativeError.ThrowException(Resources.HandleDangerousRef);
}
// CA2001:AvoidCallingProblematicMethods
streamName = Marshal.PtrToStringUni(buffer, (int)numberOfBytesRead / 2);
// Returned stream name format: ":streamName:$DATA"
streamSearchName = streamName.TrimStart(Path.StreamSeparatorChar).Replace(Path.StreamSeparator + "$DATA", string.Empty);
}
if (originalName == null || (streamSearchName != null && streamSearchName.Equals(originalName, StringComparison.OrdinalIgnoreCase)))
{
yield return(new AlternateDataStreamInfo(stream, transaction, pathLp ?? path, streamName, originalName ?? streamSearchName, isFolder, isFullPath));
}
}
uint lo, hi;
doLoop = !NativeMethods.BackupSeek(safeHandle, uint.MinValue, uint.MaxValue, out lo, out hi, out context);
}
}
// MSDN: To release the memory used by the data structure,
// call BackupRead with the bAbort parameter set to TRUE when the backup operation is complete.
if (!NativeMethods.BackupRead(safeHandle, safeBuffer, 0, out numberOfBytesRead, true, false, out context))
{
// Throws IOException.
NativeError.ThrowException(Marshal.GetLastWin32Error(), pathLp, true);
}
}
}
finally
{
// Handle is ours, dispose.
if (!callerHandle && safeHandle != null)
{
safeHandle.Close();
}
}
}
