private bool IsBoring( TrackerStateHolder holder )
{
long boringThreshold =
TimeService.Now.AddMinutes( -Properties.Settings.Default.TrackerLifetimeWithoutAccess ).ToFileTime( );
long accessTimestamp =
Interlocked.Read( ref holder.ThreadDesynchronizedAccessTimestamp );
return accessTimestamp < boringThreshold;
}
internal bool AddMissingTrackers( List<TrackerName> trackerIds )
{
// TODO: test with Thread.Sleep(x000) in the beginning
bool newTrackersAdded = false;
try
{
if ( Log.IsDebugEnabled )
Log.DebugFormat( "Adding {0} new tracker(s)...", trackerIds.Count );
HolderRwLock.AttemptEnterWriteLock( );
try
{
foreach ( TrackerName trackerId in trackerIds )
{
if ( Trackers.ContainsKey( trackerId.ForeignId ) )
{
if ( Log.IsDebugEnabled )
Log.DebugFormat( "Already added: '{0}' / {1}", trackerId.Name, trackerId.ForeignId );
}
else
{
if ( Log.IsDebugEnabled )
Log.DebugFormat( "Adding '{0}' / {1}...", trackerId.Name, trackerId.ForeignId );
// no data yet, so leave its Snapshot field null for the moment:
TrackerStateHolder trackerStateHolder = new TrackerStateHolder( trackerId.ForeignId );
Trackers.Add( trackerId.ForeignId, trackerStateHolder );
newTrackersAdded = true;
}
}
}
finally
{
HolderRwLock.ExitWriteLock( );
}
if ( Log.IsDebugEnabled )
Log.Debug( "New tracker(s) added" );
}
catch ( Exception exc )
{
Log.Error( "Error when adding trackers", exc );
}
return newTrackersAdded;
}
private static TrackerStateHolder GetMoreStaleTracker( TrackerStateHolder h1, TrackerStateHolder h2 )
{
// for the main application it doesn't matter which tracker to take if times are equal,
// so do not use out parameter:
bool unused;
return GetMoreStaleTracker( h1, h2, out unused );
}
private DateTime prevTimeAbortsChecked; // on construction set to default DateTime which is quite long time ago.
#endregion Fields
#region Methods
/// <summary>
/// Methid is made public for the unit tests only. See Remarks section for details.
/// </summary>
/// <remarks>
/// - Holders with ScheduledTime set are always less stale than others, because it's trackers
/// which were scheduled but for some reasons (error?) didn't started requests. So avoid
/// scheduling those trackers on and on again (failing to request due to the same error)
/// while there are others waiting.
/// - Holder without RefreshTime is always more stale than a holder with a RefreshTime. I.e.
/// trackers that just requested by clients should be refreshed first.
///
/// * From two holders without ScheduledTime and without RefreshTime, more stale is one with
/// earlier <see cref="TrackerStateHolder.AddedTime"/>.
/// * From two holders without ScheduledTime and with RefreshTime, more stale is one with
/// earlier <see cref="TrackerStateHolder.RefreshTime"/>.
/// * From two holders with ScheduledTime, more stale is one with earlier ScheduledTime.
///
/// Parameter <paramref name="areEqual"/> is needed for sorting only. When both trackers are
/// equal then it's not allowed to return any as "most stale" - because if any of the equal
/// is returned as "lesser", then it becomes important which of the pair goes as the 1st parameter
/// and which goes as the 2nd. In other words, transitivity and conversing rules will be broken,
/// which are absolutely critical for sorting which needed in the unit tests. Notice that it's
/// not important for the main app where just any of the trackers with equal times can be picked
/// up. But for the unit tests equality needs to be recognised as well.
/// </remarks>
public static TrackerStateHolder GetMoreStaleTracker(
TrackerStateHolder x,
TrackerStateHolder y,
out bool areEqual
)
{
// The logic in this method is quite fragile, so always run the unit test after making just
// any change here.
DateTime t1, t2;
if ( x.ScheduledTime != null && y.ScheduledTime != null )
{
t1 = x.ScheduledTime.Value;
t2 = y.ScheduledTime.Value;
}
else if ( x.ScheduledTime != null ) // means "and y.ScheduledTime == null"
{
areEqual = false;
return y;
}
else if ( y.ScheduledTime != null ) // means "and x.ScheduledTime == null"
{
areEqual = false;
return x;
}
// at this point x.ScheduledTime == null && y.ScheduledTime == null )
else if ( x.RefreshTime != null && y.RefreshTime != null )
{
t1 = x.RefreshTime.Value;
t2 = y.RefreshTime.Value;
}
else if ( x.RefreshTime != null ) // means "and y.RefreshTime == null"
{
areEqual = false;
return y;
}
else if ( y.RefreshTime != null ) // means "and x.RefreshTime == null"
{
areEqual = false;
return x;
}
else
{
// at this point x.ScheduledTime == null && y.ScheduledTime == null
// && x.RefreshTime == null && y.RefreshTime == null
t1 = x.AddedTime;
t2 = y.AddedTime;
}
areEqual = t1 == t2;
return t1 < t2 ? x : y;
}
