private static async Task <Document> GetTransformedDocumentAsync(Document document, Diagnostic diagnostic, CancellationToken cancellationToken)
{
var documentRoot = await document.GetSyntaxRootAsync(cancellationToken).ConfigureAwait(false);
SyntaxNode syntax = documentRoot.FindNode(diagnostic.Location.SourceSpan);
if (syntax == null)
{
return(document);
}
MethodDeclarationSyntax methodDeclarationSyntax = syntax.FirstAncestorOrSelf <MethodDeclarationSyntax>();
DelegateDeclarationSyntax delegateDeclarationSyntax = syntax.FirstAncestorOrSelf <DelegateDeclarationSyntax>();
if (methodDeclarationSyntax == null && delegateDeclarationSyntax == null)
{
return(document);
}
DocumentationCommentTriviaSyntax documentationComment =
methodDeclarationSyntax?.GetDocumentationCommentTriviaSyntax()
?? delegateDeclarationSyntax?.GetDocumentationCommentTriviaSyntax();
if (documentationComment == null)
{
return(document);
}
SemanticModel semanticModel = await document.GetSemanticModelAsync(cancellationToken).ConfigureAwait(false);
bool isTask;
bool isAsynchronousTestMethod;
if (methodDeclarationSyntax != null)
{
isTask = IsTaskReturningMethod(semanticModel, methodDeclarationSyntax, cancellationToken);
isAsynchronousTestMethod = isTask && IsAsynchronousTestMethod(semanticModel, methodDeclarationSyntax, cancellationToken);
}
else
{
isTask = IsTaskReturningMethod(semanticModel, delegateDeclarationSyntax, cancellationToken);
isAsynchronousTestMethod = false;
}
XmlNodeSyntax returnsElement = documentationComment.Content.GetFirstXmlElement(XmlCommentHelper.ReturnsXmlTag) as XmlNodeSyntax;
if (returnsElement != null && !isTask)
{
// This code fix doesn't know how to do anything more than document Task-returning methods.
return(document);
}
SyntaxList <XmlNodeSyntax> content = XmlSyntaxFactory.List();
if (isTask)
{
content = content.Add(XmlSyntaxFactory.Text("A "));
content = content.Add(XmlSyntaxFactory.SeeElement(SyntaxFactory.TypeCref(SyntaxFactory.ParseTypeName("global::System.Threading.Tasks.Task"))).WithAdditionalAnnotations(Simplifier.Annotation));
string operationKind = isAsynchronousTestMethod ? "unit test" : "operation";
content = content.Add(XmlSyntaxFactory.Text($" representing the asynchronous {operationKind}."));
// wrap the generated content in a <placeholder> element for review.
content = XmlSyntaxFactory.List(XmlSyntaxFactory.PlaceholderElement(content));
}
// Try to replace an existing <returns> element if the comment contains one. Otherwise, add it as a new element.
SyntaxNode root = await document.GetSyntaxRootAsync(cancellationToken).ConfigureAwait(false);
SyntaxNode newRoot;
if (returnsElement != null)
{
XmlEmptyElementSyntax emptyElement = returnsElement as XmlEmptyElementSyntax;
if (emptyElement != null)
{
XmlElementSyntax updatedReturns = XmlSyntaxFactory.Element(XmlCommentHelper.ReturnsXmlTag, content)
.WithLeadingTrivia(returnsElement.GetLeadingTrivia())
.WithTrailingTrivia(returnsElement.GetTrailingTrivia());
newRoot = root.ReplaceNode(returnsElement, updatedReturns);
}
else
{
XmlElementSyntax updatedReturns = ((XmlElementSyntax)returnsElement).WithContent(content);
newRoot = root.ReplaceNode(returnsElement, updatedReturns);
}
}
else
{
string newLineText = document.Project.Solution.Workspace.Options.GetOption(FormattingOptions.NewLine, LanguageNames.CSharp);
returnsElement = XmlSyntaxFactory.Element(XmlCommentHelper.ReturnsXmlTag, content);
XmlNodeSyntax leadingNewLine = XmlSyntaxFactory.NewLine(newLineText);
// HACK: The formatter isn't working when contents are added to an existing documentation comment, so we
// manually apply the indentation from the last line of the existing comment to each new line of the
// generated content.
SyntaxTrivia exteriorTrivia = GetLastDocumentationCommentExteriorTrivia(documentationComment);
if (!exteriorTrivia.Token.IsMissing)
{
leadingNewLine = leadingNewLine.ReplaceExteriorTrivia(exteriorTrivia);
returnsElement = returnsElement.ReplaceExteriorTrivia(exteriorTrivia);
}
DocumentationCommentTriviaSyntax newDocumentationComment = documentationComment.WithContent(
documentationComment.Content.InsertRange(
documentationComment.Content.Count - 1,
XmlSyntaxFactory.List(leadingNewLine, returnsElement)));
newRoot = root.ReplaceNode(documentationComment, newDocumentationComment);
}
return(document.WithSyntaxRoot(newRoot));
}