/// <summary>
/// Returns a list of all files and folders changed since the USN
/// </summary>
/// <param name="startUsn">The USN number to start the list from, set to zero to get all</param>
/// <returns>A list of files and folders changed since the USN</returns>
private List <KeyValuePair <string, Win32USN.USN_RECORD> > BuildUSNTable(long startUsn)
{
const int ALLOCATED_MEMORY = 64 * 1024;
IntPtr allocatedMemory = IntPtr.Zero;
List <KeyValuePair <string, Win32USN.USN_RECORD> > records = new List <KeyValuePair <string, Win32USN.USN_RECORD> >();
try
{
uint bytesRead = 0;
bool more = true;
allocatedMemory = Marshal.AllocHGlobal(ALLOCATED_MEMORY);
Win32USN.MFT_ENUM_DATA startParams = new Win32USN.MFT_ENUM_DATA();
startParams.StartFileReferenceNumber = 0;
startParams.LowUsn = Math.Max(startUsn, m_journal.LowestValidUsn);
startParams.HighUsn = m_journal.NextUsn;
while (more)
{
if (!Win32USN.DeviceIoControl(m_volumeHandle, Win32USN.EIOControlCode.FsctlEnumUsnData,
ref startParams, (uint)Marshal.SizeOf(typeof(Win32USN.MFT_ENUM_DATA)),
allocatedMemory, ALLOCATED_MEMORY,
ref bytesRead, IntPtr.Zero))
{
int errorCode = Marshal.GetLastWin32Error();
//If we get no error or EOF the enumeration is completed
if (errorCode == Win32USN.ERROR_HANDLE_EOF || errorCode == Win32USN.ERROR_SUCCESS)
{
break;
}
else
{
throw new Win32Exception(errorCode);
}
}
startParams.StartFileReferenceNumber = (ulong)ExtractUsnEntries(bytesRead, allocatedMemory, records, out more);
}
return(ParseRecordList(records));
}
finally
{
if (allocatedMemory != IntPtr.Zero)
{
Marshal.FreeHGlobal(allocatedMemory);
allocatedMemory = IntPtr.Zero;
}
}
}
/// <summary>
/// Retrieves a USN_RECORD_V2 by file reference number (FRN, not USN!)
/// </summary>
/// <param name="frn">File reference number</param>
/// <returns>Returned entry if successful; null otherwise</returns>
private Record GetRecordByFileRef(ulong frn)
{
var enumData = new Win32USN.MFT_ENUM_DATA
{
StartFileReferenceNumber = frn,
LowUsn = 0,
HighUsn = m_journal.NextUsn
};
var bufferSize = 512;
byte[] entryData;
while (!Win32USN.ControlWithInput(m_volumeHandle, Win32USN.FsCtl.EnumUSNData,
ref enumData, bufferSize, out entryData))
{
var e = Marshal.GetLastWin32Error();
if (e != Win32USN.ERROR_INSUFFICIENT_BUFFER)
{
return(null);
}
// retry, increasing buffer size
bufferSize *= 2;
}
// not really a foreach: we only check the first record
foreach (var rec in EnumerateRecords(entryData))
{
if (rec.UsnRecord.FileReferenceNumber == frn)
{
return(rec);
}
break;
}
return(null);
}
/// <summary>
/// Returns a list of all files and folders changed since the USN
/// </summary>
/// <param name="startUsn">The USN number to start the list from, set to zero to get all</param>
/// <returns>A list of files and folders changed since the USN</returns>
private List<KeyValuePair<string, Win32USN.USN_RECORD>> BuildUSNTable(long startUsn)
{
const int ALLOCATED_MEMORY = 64 * 1024;
IntPtr allocatedMemory = IntPtr.Zero;
List<KeyValuePair<string, Win32USN.USN_RECORD>> records = new List<KeyValuePair<string, Win32USN.USN_RECORD>>();
try
{
uint bytesRead = 0;
bool more = true;
allocatedMemory = Marshal.AllocHGlobal(ALLOCATED_MEMORY);
Win32USN.MFT_ENUM_DATA startParams = new Win32USN.MFT_ENUM_DATA();
startParams.StartFileReferenceNumber = 0;
startParams.LowUsn = Math.Max(startUsn, m_journal.LowestValidUsn);
startParams.HighUsn = m_journal.NextUsn;
while (more)
{
if (!Win32USN.DeviceIoControl(m_volumeHandle, Win32USN.EIOControlCode.FsctlEnumUsnData,
ref startParams, (uint)Marshal.SizeOf(typeof(Win32USN.MFT_ENUM_DATA)),
allocatedMemory, ALLOCATED_MEMORY,
ref bytesRead, IntPtr.Zero))
{
int errorCode = Marshal.GetLastWin32Error();
//If we get no error or EOF the enumeration is completed
if (errorCode == Win32USN.ERROR_HANDLE_EOF || errorCode == Win32USN.ERROR_SUCCESS)
break;
else
throw new Win32Exception(errorCode);
}
startParams.StartFileReferenceNumber = (ulong)ExtractUsnEntries(bytesRead, allocatedMemory, records, out more);
}
return ParseRecordList(records);
}
finally
{
if (allocatedMemory != IntPtr.Zero)
{
Marshal.FreeHGlobal(allocatedMemory);
allocatedMemory = IntPtr.Zero;
}
}
}
