/// <summary>
/// Return an enumeration of the most recent transactions in the transaction log in
/// time order (oldest first)
/// </summary>
/// <param name="maxCount">The maximum number of transactions to return</param>
/// <param name="ts">The maximum age of transaction to return</param>
/// <returns>An enumeration of the <paramref name="maxCount"/> most recent transactions that match the age filter</returns>
public List <ITransactionInfo> GetTransactionList(int maxCount, TimeSpan ts)
{
if (!_persistenceManager.FileExists(GetTransactionLogHeaderFile()))
{
return(new List <ITransactionInfo>());
}
using (var stream = _persistenceManager.GetInputStream(GetTransactionLogHeaderFile()))
{
long firstRecordOffset = maxCount * TransactionInfo.TransactionInfoRecordSize;
if (firstRecordOffset > stream.Length)
{
stream.Seek(0, SeekOrigin.Begin);
}
else
{
stream.Seek(firstRecordOffset, SeekOrigin.End);
}
var reader = new BinaryReader(stream);
var oldestToReturn = DateTime.UtcNow.Subtract(ts);
var ret = new List <ITransactionInfo>(maxCount);
while (true)
{
try
{
var txnInfo = TransactionInfo.Load(reader);
if (txnInfo.TransactionStartTime > oldestToReturn)
{
ret.Add(txnInfo);
}
}
catch (EndOfStreamException)
{
break;
}
}
return(ret);
}
}
public ITransactionInfo ReadTransactionInfo(int transactionNumber)
{
if (!_persistenceManager.FileExists(GetTransactionLogHeaderFile()))
{
return(null);
}
using (var stream = _persistenceManager.GetInputStream(GetTransactionLogHeaderFile()))
{
var readPosition = transactionNumber * TransactionInfo.TransactionInfoRecordSize;
// check if this is a valid transaction number, return null if beyond end of file.
if (readPosition > stream.Length)
{
return(null);
}
// seek to position
stream.Seek(-readPosition, SeekOrigin.End);
// read
return(TransactionInfo.Load(new BinaryReader(stream)));
}
}
