private void AddClassifiedSpansForPreviousTree( IClassificationService classificationService, SnapshotSpan span, ITextSnapshot lastSnapshot, Document lastDocument, List <ClassifiedSpan> classifiedSpans) { // Slightly more complicated case. They're asking for the classifications for a // different snapshot than what we have a parse tree for. So we first translate the span // that they're asking for so that is maps onto the tree that we have spans for. We then // get the classifications from that tree. We then take the results and translate them // back to the snapshot they want. Finally, as some of the classifications may have // changed, we check for some common cases and touch them up manually so that things // look right for the user. // Note the handling of SpanTrackingModes here: We do EdgeExclusive while mapping back , // and EdgeInclusive mapping forward. What I've convinced myself is that EdgeExclusive // is best when mapping back over a deletion, so that we don't end up classifying all of // the deleted code. In most addition/modification cases, there will be overlap with // existing spans, and so we'll end up classifying well. In the worst case, there is a // large addition that doesn't exist when we map back, and so we don't have any // classifications for it. That's probably okay, because: // 1. If it's that large, it's likely that in reality there are multiple classification // spans within it. // 2.We'll eventually call ClassificationsChanged and re-classify that region anyway. // When mapping back forward, we use EdgeInclusive so that in the common typing cases we // don't end up with half a token colored differently than the other half. // See bugs like http://vstfdevdiv:8080/web/wi.aspx?id=6176 for an example of what can // happen when this goes wrong. // 1) translate the requested span onto the right span for the snapshot that corresponds // to the syntax tree. var translatedSpan = span.TranslateTo(lastSnapshot, SpanTrackingMode.EdgeExclusive); if (translatedSpan.IsEmpty) { // well, there is no information we can get from previous tree, use lexer to // classify given span. soon we will re-classify the region. AddClassifiedSpansForTokens(classificationService, span, classifiedSpans); return; } var tempList = ClassificationUtilities.GetOrCreateClassifiedSpanList(); AddClassifiedSpansForCurrentTree( classificationService, translatedSpan, lastDocument, tempList); var currentSnapshot = span.Snapshot; var currentText = currentSnapshot.AsText(); foreach (var lastClassifiedSpan in tempList) { // 2) Translate those classifications forward so that they correspond to the true // requested snapshot. var lastSnapshotSpan = lastClassifiedSpan.TextSpan.ToSnapshotSpan(lastSnapshot); var currentSnapshotSpan = lastSnapshotSpan.TranslateTo(currentSnapshot, SpanTrackingMode.EdgeInclusive); var currentClassifiedSpan = new ClassifiedSpan(lastClassifiedSpan.ClassificationType, currentSnapshotSpan.Span.ToTextSpan()); // 3) The classifications may be incorrect due to changes in the text. For example, // if "clss" becomes "class", then we want to changes the classification from // 'identifier' to 'keyword'. currentClassifiedSpan = classificationService.AdjustStaleClassification(currentText, currentClassifiedSpan); classifiedSpans.Add(currentClassifiedSpan); } ClassificationUtilities.ReturnClassifiedSpanList(tempList); }
public ClassifiedSpan AdjustStaleClassification(SourceText text, ClassifiedSpan classifiedSpan) => _originalService.AdjustStaleClassification(text, classifiedSpan);