internal void ComputeSourceEdits(FrugalList <TextChange> changes)
{
ITextEdit xedit = this.group.GetEdit((BaseBuffer)this.sourceBuffer);
foreach (TextChange change in changes)
{
if (change.OldLength > 0)
{
IList <SnapshotSpan> sourceDeletionSpans = this.currentElisionSnapshot.MapToSourceSnapshots(new Span(change.OldPosition, change.OldLength));
foreach (SnapshotSpan sourceDeletionSpan in sourceDeletionSpans)
{
xedit.Delete(sourceDeletionSpan);
}
}
if (change.NewLength > 0)
{
// change includes an insertion
ReadOnlyCollection <SnapshotPoint> sourceInsertionPoints = this.currentElisionSnapshot.MapInsertionPointToSourceSnapshots(change.OldPosition, null);
if (sourceInsertionPoints.Count == 1)
{
// the insertion point is unambiguous
xedit.Insert(sourceInsertionPoints[0].Position, change.NewText);
}
else
{
// the insertion is at the boundary of source spans
int[] insertionSizes = new int[sourceInsertionPoints.Count];
if (this.resolver != null)
{
this.resolver.FillInInsertionSizes(new SnapshotPoint(this.currentElisionSnapshot, change.OldPosition),
sourceInsertionPoints, change.NewText, insertionSizes);
}
// if resolver was not provided, we just use zeros for the insertion sizes, which will push the entire insertion
// into the last slot.
int pos = 0;
for (int i = 0; i < insertionSizes.Length; ++i)
{
// contend with any old garbage that the client passed back.
int size = (i == insertionSizes.Length - 1)
? change.NewLength - pos
: Math.Min(insertionSizes[i], change.NewLength - pos);
if (size > 0)
{
xedit.Insert(sourceInsertionPoints[i].Position, TextChange.ChangeNewSubstring(change, pos, size));
pos += size;
if (pos == change.NewLength)
{
break; // inserted text is used up, whether we've visited all of the insertionSizes or not
}
}
}
}
}
}
this.editApplicationInProgress = true;
}
