public EventIdentificationStore(IFilterConfiguration configuration)
{
_store = GetIsolatedStorageFile();
_configurationHash = HashBuilder.BuildFilterConfigHash(configuration);
_store.CreateRadonDirectoryIfNotExists();
}
public void SaveAlreadyReportedEventIdentification(LogEvent logEvent)
{
lock (_fileAccessLock)
{
using (var stream = new IsolatedStorageFileStream(Path.Combine("Radon", _configurationHash), FileMode.Create, _store))
using (var writer = new StreamWriter(stream))
{
var id = HashBuilder.BuildEventIdentification(logEvent);
writer.WriteLine(id.TimeStampUtc.ToString("u"));
writer.WriteLine(id.Hash);
}
}
}
public IEnumerable <LogEvent> ReadEvents()
{
var oldEventIdentification = _identificationStore.GetAlreadyReportedEventIdentification();
var events = _eventReader.ReadEvents();
if (oldEventIdentification == null)
{
return(events);
}
var filteredEvents =
events.TakeWhile(
e =>
{
var newerThan = e.TimeGenerated.ToUniversalTime() > oldEventIdentification.TimeStampUtc;
if (newerThan)
{
// The event is newer than the old event
return(true);
}
else
{
if (e.TimeGenerated.ToUniversalTime() == oldEventIdentification.TimeStampUtc)
{
var eventHash = HashBuilder.BuildEventIdentification(e).Hash;
if (eventHash != oldEventIdentification.Hash)
{
// The event is the same age as the old event but has a different hash
return(true);
}
}
}
return(false); // The event wasn't newer than than the old event or the same age and hash -> stop returning older events
});
return(filteredEvents);
}