internal TrackingCacheData Merge(ITextSnapshot snapshot, TrackingCacheData trackingCacheData)
{
var left = TrackingSpan.GetSpanSafe(snapshot);
var right = trackingCacheData.TrackingSpan.GetSpanSafe(snapshot);
SnapshotSpan span;
if (left.HasValue && right.HasValue)
{
span = left.Value.CreateOverarching(right.Value);
}
else if (left.HasValue)
{
span = left.Value;
}
else if (right.HasValue)
{
span = right.Value;
}
else
{
span = new SnapshotSpan(snapshot, 0, 0);
}
var trackingSpan = snapshot.CreateTrackingSpan(span, SpanTrackingMode.EdgeInclusive);
var tagList = TrackingList
.Concat(trackingCacheData.TrackingList)
.Distinct(EqualityUtility.Create <Tuple <ITrackingSpan, TTag> >(
(x, y) => x.Item1.GetSpanSafe(snapshot) == y.Item1.GetSpanSafe(snapshot),
tuple => tuple.Item1.GetSpanSafe(snapshot).GetHashCode()))
.ToReadOnlyCollection();
return(new TrackingCacheData(trackingSpan, tagList));
}