public ElisionMap EditSpans(ITextSnapshot sourceSnapshot,
NormalizedSpanCollection spansToElide,
NormalizedSpanCollection spansToExpand,
out FrugalList <TextChange> textChanges)
{
textChanges = new FrugalList <TextChange>();
NormalizedSpanCollection beforeSourceSpans = new NormalizedSnapshotSpanCollection(GetSourceSpans(sourceSnapshot, 0, this.spanCount));
NormalizedSpanCollection afterElisionSourceSpans = NormalizedSpanCollection.Difference(beforeSourceSpans, spansToElide);
NormalizedSpanCollection elisionChangeSpans = NormalizedSpanCollection.Difference(beforeSourceSpans, afterElisionSourceSpans);
foreach (Span s in elisionChangeSpans)
{
textChanges.Add(TextChange.Create(this.root.MapFromSourceSnapshotToNearest(s.Start, 0),
BufferFactoryService.StringRebuilderFromSnapshotAndSpan(sourceSnapshot, s),
StringRebuilder.Empty,
sourceSnapshot));
}
NormalizedSpanCollection afterExpansionSourceSpans = NormalizedSpanCollection.Union(afterElisionSourceSpans, spansToExpand);
NormalizedSpanCollection expansionChangeSpans = NormalizedSpanCollection.Difference(afterExpansionSourceSpans, afterElisionSourceSpans);
foreach (Span s in expansionChangeSpans)
{
textChanges.Add(TextChange.Create(this.root.MapFromSourceSnapshotToNearest(s.Start, 0),
StringRebuilder.Empty,
BufferFactoryService.StringRebuilderFromSnapshotAndSpan(sourceSnapshot, s),
sourceSnapshot));
}
return(textChanges.Count > 0 ? new ElisionMap(sourceSnapshot, afterExpansionSourceSpans) : this);
}
private void ConstructChanges()
{
var diffs = differ.GetDifferences();
List <TextChange> changes = new List <TextChange>();
int pos = this.textPosition;
// each difference generates a text change
foreach (Difference diff in diffs)
{
pos += GetMatchSize(diffs.LeftSequence, diff.Before);
TextChange change = TextChange.Create(pos,
BufferFactoryService.StringRebuilderFromSnapshotSpans(diffs.LeftSequence, diff.Left),
BufferFactoryService.StringRebuilderFromSnapshotSpans(diffs.RightSequence, diff.Right),
this.currentSnapshot);
changes.Add(change);
pos += change.OldLength;
}
this.normalizedChanges = NormalizedTextChangeCollection.Create(changes);
}