public async System.Threading.Tasks.Task<IEnumerable<CodeAction>> GetRefactoringsAsync(Document document, TextSpan textSpan, CancellationToken cancellationToken)
{
if (textSpan.IsEmpty)
{
return null;
}
if (String.IsNullOrWhiteSpace(document.GetText().GetSubText(textSpan).ToString())) { return null; }
var tree = (SyntaxTree)document.GetSyntaxTree(cancellationToken);
var diagnostics = tree.GetDiagnostics(cancellationToken);
if (diagnostics.Any(d => d.Severity == DiagnosticSeverity.Error || d.IsWarningAsError)) return null;
var linespan = tree.GetLocation(textSpan).GetLineSpan(false);
if (linespan.EndLinePosition.Line <= linespan.StartLinePosition.Line) return null; // single line
var semanticModel = (SemanticModel)document.GetSemanticModel(cancellationToken);
var sdiag = semanticModel.GetDiagnostics(cancellationToken);
if (sdiag == null) return null;
if (sdiag.Any(d => d.Severity == DiagnosticSeverity.Error || d.IsWarningAsError)) return null;
var methodExtractor = new MethodExtractor(semanticModel, document, textSpan, this.options);
var newDocument = methodExtractor.GetRefactoredDocument(cancellationToken);
if (newDocument == null) return null;
var action = new ClousotExtractMethodAction(newDocument);
return new List<CodeAction>{ action };
}