Microsoft.R.Editor.Tree.EditorTree.Build C# (CSharp) Method

        public void Build() {
            if (_ownerThread != Thread.CurrentThread.ManagedThreadId)
                throw new ThreadStateException("Method should only be called on the main thread");

            var sw = Stopwatch.StartNew();

            TreeUpdateTask.Cancel();

            if (TextBuffer != null) {
                TextSnapshot = TextBuffer.CurrentSnapshot;
                _astRoot = RParser.Parse(new TextProvider(TextBuffer.CurrentSnapshot), ExpressionTermFilter);
            }

            TreeUpdateTask.ClearChanges();

            // Fire UpdatesPending notification, even though we don't have ranges for the event
            List<TextChangeEventArgs> textChanges = new List<TextChangeEventArgs>();
            FireOnUpdatesPending(textChanges);

            FireOnUpdateBegin();
            FireOnUpdateCompleted(TreeUpdateType.NewTree);

            sw.Stop();
        }

        public static EditorTree ApplyTextChange(string expression, int start, int oldLength, int newLength, string newText)
        {
            TextBufferMock textBuffer = new TextBufferMock(expression, RContentTypeDefinition.ContentType);

            EditorTree tree = new EditorTree(textBuffer);
            tree.Build();

            TextChange tc = new TextChange();
            tc.OldRange = new TextRange(start, oldLength);
            tc.NewRange = new TextRange(start, newLength);
            tc.OldTextProvider = new TextProvider(textBuffer.CurrentSnapshot);

            if (oldLength == 0 && newText.Length > 0)
            {
                textBuffer.Insert(start, newText);
            }
            else if (oldLength > 0 && newText.Length > 0)
            {
                textBuffer.Replace(new Span(start, oldLength), newText);
            }
            else
            {
                textBuffer.Delete(new Span(start, oldLength));
            }

            return tree;
        }