public bool IsLogClean()
{
if (m_restartPage == null)
{
m_restartPage = ReadRestartPage();
}
bool isLogFileClosed = (m_restartPage.LogRestartArea.ClientInUseList == LogRestartArea.NoClients);
if (isLogFileClosed)
{
// Windows 2000 and earlier will close the log file by setting the ClientInUseList to NoClients when the volume is shutdown cleanly.
// If the log file is closed than it must be clean.
return(true);
}
else if ((m_restartPage.LogRestartArea.Flags & LogRestartFlags.LogFileIsClean) != 0)
{
// Windows XP and later will set the clean bit when the volume is shutdown cleanly.
// If the clean bit is set than the log file must be clean.
return(true);
}
else
{
// The volume has not been shutdown cleanly.
// It's possible that the log is clean if the volume was completely idle for at least five seconds preceding the unclean shutdown.
// Currently, we skip the analysis and assume that's not the case.
return(false);
}
}
public LogRecord ReadCurrentRestartRecord()
{
if (m_restartPage == null)
{
m_restartPage = ReadRestartPage();
}
return(ReadRecord(m_restartPage.LogRestartArea.CurrentLsn));
}
private int LsnToRecordOffsetInPage(ulong lsn)
{
if (m_restartPage == null)
{
m_restartPage = ReadRestartPage();
}
return((int)((lsn << 3) & (m_restartPage.LogPageSize - 1)));
}
private void WritePage(ulong pageOffset, LogRecordPage page)
{
if (m_restartPage == null)
{
m_restartPage = ReadRestartPage();
}
byte[] pageBytes = page.GetBytes((int)m_restartPage.LogPageSize, m_restartPage.LogRestartArea.LogPageDataOffset);
WriteData(pageOffset, pageBytes);
}
private LogRecordPage ReadPageFromFile(ulong pageOffset)
{
if (m_restartPage == null)
{
m_restartPage = ReadRestartPage();
}
byte[] pageBytes = ReadData(pageOffset, (int)m_restartPage.LogPageSize);
return(new LogRecordPage(pageBytes, 0, m_restartPage.LogRestartArea.LogPageDataOffset));
}
public LogRecord ReadRecord(ulong lsn)
{
if (m_restartPage == null)
{
m_restartPage = ReadRestartPage();
}
ulong pageOffsetInFile = LsnToPageOffsetInFile(lsn);
int recordOffsetInPage = LsnToRecordOffsetInPage(lsn);
LogRecordPage page = ReadPage(pageOffsetInFile);
return(page.ReadRecord(recordOffsetInPage, m_restartPage.LogRestartArea.LogPageDataOffset));
}
public LogRestartPage ReadRestartPage()
{
byte[] pageBytes = ReadData(0, Volume.BytesPerSector);
uint systemPageSize = LogRestartPage.GetSystemPageSize(pageBytes, 0);
int bytesToRead = (int)systemPageSize - pageBytes.Length;
if (bytesToRead > 0)
{
byte[] temp = ReadData((ulong)pageBytes.Length, bytesToRead);
pageBytes = ByteUtils.Concatenate(pageBytes, temp);
}
m_restartPage = new LogRestartPage(pageBytes, 0);
return(m_restartPage);
}
private int FindClientIndex(string clientName)
{
if (m_restartPage == null)
{
m_restartPage = ReadRestartPage();
}
for (int index = 0; index < m_restartPage.LogRestartArea.LogClientArray.Count; index++)
{
if (String.Equals(m_restartPage.LogRestartArea.LogClientArray[index].ClientName, clientName, StringComparison.OrdinalIgnoreCase))
{
return(index);
}
}
return(-1);
}
