internal ulong GetLatestStorePositionFromMasterFile(string masterFilePath)
{
try
{
Logging.LogDebug("Retrieving latest store position from masterfile : {0}", masterFilePath);
using (var fs = _persistenceManager.GetInputStream(masterFilePath))
{
Logging.LogDebug("Masterfile stream length is {0}", fs.Length);
Logging.LogDebug("Attempting to seek to {0} bytes from end of stream.", CommitPoint.RecordSize);
fs.Seek(-CommitPoint.RecordSize, SeekOrigin.End);
Logging.LogDebug("Seek completed ok. Attempting to load commit point");
var commitPoint = CommitPoint.Load(fs);
Logging.LogDebug("Commit point load completed OK. Returning commit point offset as {0}", commitPoint.LocationOffset);
return(commitPoint.LocationOffset);
}
}
catch (InvalidCommitPointException icp)
{
Logging.LogInfo("Caught InvalidCommitPointException: {0}", icp);
// start reading from the start of the file until we get to the dud one.
// truncate the file at this point. log it and try again.
var count = 0;
CommitPoint validCommitPoint = null;
const int headerSize = MasterfileHeaderLongCount * 8;
while (true)
{
using (var fs = _persistenceManager.GetInputStream(masterFilePath))
{
try
{
Logging.LogInfo("Reading commit point at " + CommitPoint.RecordSize * count);
fs.Seek((CommitPoint.RecordSize * count) + headerSize, SeekOrigin.Begin);
var commitPoint = CommitPoint.Load(fs);
validCommitPoint = commitPoint;
count++;
}
catch (BrightstarInternalException)
{
var startOfBadCommit = (CommitPoint.RecordSize * count) + headerSize;
Logging.LogInfo("Truncating file at " + startOfBadCommit);
// truncate file.
using (var stream = _persistenceManager.GetOutputStream(masterFilePath, FileMode.Truncate))
{
stream.SetLength(startOfBadCommit);
}
// return last good commit
return(validCommitPoint.LocationOffset);
}
}
}
}
catch (Exception ex)
{
throw new BrightstarInternalException("Error while trying to recover to last valid commit point.", ex);
}
}
public CommitPoint GetCommitPoint(string storeLocation, ulong offset)
{
var masterFileLocation = Path.Combine(storeLocation, MasterFileName);
using (var fs = _persistenceManager.GetInputStream(masterFileLocation))
{
fs.Seek((long)offset, SeekOrigin.Begin);
var commitPoint = CommitPoint.Load(fs);
return(commitPoint);
}
}
public IEnumerable <CommitPoint> GetCommitPoints(string storeLocation)
{
var masterFileLocation = Path.Combine(storeLocation, MasterFileName);
var pos = 1;
using (var fs = _persistenceManager.GetInputStream(masterFileLocation))
{
while ((pos * CommitPoint.RecordSize) + MasterfileHeaderSize <= fs.Length)
{
fs.Seek(-(pos * CommitPoint.RecordSize), SeekOrigin.End);
var commitPoint = CommitPoint.Load(fs);
pos++;
yield return(commitPoint);
}
}
}
