/// <summary>
/// Returns the orphaned transaction <see cref="Guid" />s discovered after
/// <see cref="Open" /> returns <see cref="LogStatus.Recover" />.
/// </summary>
/// <returns>The list of transaction <see cref="Guid" />s.</returns>
/// <exception cref="TransactionException">Thrown if the log is not open.</exception>
/// <remarks>
/// This method returns only the IDs for valid, non-corrupted transaction
/// operation logs. It will delete any corrupted logs it finds.
/// </remarks>
public List <Guid> GetOrphanTransactions()
{
var orphans = new List <Guid>();
Guid id;
using (TimedLock.Lock(syncLock))
{
if (!isOpen)
{
throw new TransactionException(NotOpenMsg);
}
foreach (string file in Helper.GetFilesByPattern(folder + Helper.PathSepString + "*.log", SearchOption.AllDirectories))
{
if (FileOperationLog.Validate(file, out id))
{
orphans.Add(id);
}
else
{
try
{
File.Delete(file);
}
catch
{
// Ignore errors
}
}
}
return(orphans);
}
}
/// <summary>
/// Opens the transaction log, returning a <see cref="LogStatus" />
/// value indicating the state of the transaction log.
/// </summary>
/// <param name="manager">The <see cref="TransactionManager" />.</param>
/// <returns>The log's <see cref="LogStatus" /> code.</returns>
/// <remarks>
/// <para>
/// This method will return <see cref="LogStatus.Ready" /> if the log is ready to
/// begin handling transactions.
/// </para>
/// <para>
/// <see cref="LogStatus.Recover" /> will be returned if the log was not
/// closed properly (probably due to a system or application failure) and
/// there are transactions that need to be recovered. The <see cref="TransactionManager" />
/// will call <see cref="GetOrphanTransactions" /> to get the <see cref="Guid" />s of
/// the orphaned transactions and will then call <see cref="OpenOperationLog" />
/// to open each transaction operation log and then undo or redo the transaction
/// operations depending on the state of the operation log.
/// </para>
/// <para>
/// The method returns <see cref="LogStatus.Corrupt" /> if the transaction
/// log is corrupt and that there's the potential for the resource to
/// be in an inconsistent state after recovering the remaining transactions.
/// </para>
/// </remarks>
/// <exception cref="TransactionException">Thrown if the log is already open.</exception>
public LogStatus Open(TransactionManager manager)
{
bool orphans;
Guid id;
try
{
if (isOpen)
{
throw new TransactionException("Transaction log is already open.");
}
Helper.CreateFolderTree(folder);
lockFile = new FileStream(folder + Helper.PathSepString + "transactions.lock", FileMode.Create, FileAccess.ReadWrite);
orphans = false;
foreach (var file in Helper.GetFilesByPattern(folder + Helper.PathSepString + "*.log", SearchOption.AllDirectories))
{
orphans = true;
if (!FileOperationLog.Validate(file, out id))
{
return(LogStatus.Corrupt);
}
}
isOpen = true;
syncLock = manager.SyncRoot;
return(orphans ? LogStatus.Recover : LogStatus.Ready);
}
catch
{
if (lockFile != null)
{
lockFile.Close();
lockFile = null;
}
throw;
}
}
