/// <summary>
/// Handles non-trivial changes like changes that delete elements,
/// change identifier names, introducing new braces: changes
/// that cannot be handled without background parse.
/// </summary>
private void ProcessComplexChange(TextChangeContext context)
{
// Cancel background parse if it is running
Cancel();
var c = context.PendingChanges;
try {
// Get write lock since there may be concurrent readers
// of the tree. Note that there are no concurrent writers
// since changes can only come from a background parser
// and are always applied from the main thread.
_editorTree.AcquireWriteLock();
int start, oldLength, newLength;
if (Changes.FullParseRequired)
{
// When full parse is required, change is like replace the entire file
start = 0;
oldLength = c.OldTextProvider.Length;
newLength = c.NewTextProvider.Length;
// Remove damaged elements if any and reflect text change.
// the tree remains usable outside of the damaged scope.
_editorTree.InvalidateInRange(c.OldRange);
_editorTree.NotifyTextChange(c.Start, c.OldLength, c.NewLength);
}
else
{
start = c.Start;
oldLength = c.OldLength;
newLength = c.NewLength;
DeleteAndShiftElements(context);
Debug.Assert(_editorTree.AstRoot.Children.Count > 0);
}
var ttc = new TreeTextChange(start, oldLength, newLength, _editorTree.BufferSnapshot, EditorBuffer.CurrentSnapshot);
Changes.Combine(ttc);
Changes.Version = EditorBuffer?.CurrentSnapshot?.Version ?? 1;
_editorTree.BufferSnapshot = EditorBuffer.CurrentSnapshot;
} finally {
// Lock must be released before firing events otherwise we may hang
_editorTree.ReleaseWriteLock();
}
_editorTree.FireOnUpdateCompleted(TreeUpdateType.NodesRemoved);
}