private static async Task <Document> InvokeMp0101(Diagnostic diagnostic, Document document,
CancellationToken cancellationToken)
{
// 2: add a try/catch block around RequestAsync
// add block around RequestAsync call up to last
// access to any variable the result is assigned to.
// a: find span that would best fit the try
//
// b: add the catch with default code:
// catch(ReceivedErrorEventException<{3rd type parameter}> ex)
// { throw new NotImplementedException(ex.Message); }
// 3: catch...
var model = await document.GetSemanticModelAsync(cancellationToken);
var root = await document.GetSyntaxRootAsync(cancellationToken).ConfigureAwait(false);
Func <IdentifierNameSyntax, SyntaxList <StatementSyntax> > generateCatchStatements =
exceptionIdentifierName => SingletonList <StatementSyntax>(
ExpressionStatement(
InvocationExpression(
MemberAccessExpression(
SyntaxKind.SimpleMemberAccessExpression,
MemberAccessExpression(
SyntaxKind.SimpleMemberAccessExpression,
MemberAccessExpression(
SyntaxKind.SimpleMemberAccessExpression,
AliasQualifiedName(
IdentifierName(
Token(SyntaxKind.GlobalKeyword)
.WithLeadingTrivia(Comment("// TODO: do something with ex.ErrorEvent"),
CarriageReturnLineFeed)
),
IdentifierName(nameof(System))),
IdentifierName(nameof(System.Diagnostics))),
IdentifierName(nameof(Debug))),
IdentifierName(nameof(Debug.WriteLine))))
.WithArgumentList(
ArgumentList(
SingletonSeparatedList(
Argument(
MemberAccessExpression(
SyntaxKind.SimpleMemberAccessExpression,
exceptionIdentifierName,
IdentifierName(nameof(ReceivedErrorEventException <IEvent> .ErrorEvent)))))))));
// Find the type declaration identified by the diagnostic.
var subjectToken = root.FindToken(diagnostic.Location.SourceSpan.Start);
var invocation =
subjectToken.Parent.AncestorsAndSelf().OfType <InvocationExpressionSyntax>().First();
var subjectNode = root.FindNode(diagnostic.Location.SourceSpan);
var requestAsyncMemberAccess =
subjectNode.Parent.AncestorsAndSelf().OfType <MemberAccessExpressionSyntax>().First();
// verify invocation is the one we want // rule should detect this exists
if (!(invocation.Parent is AwaitExpressionSyntax))
{
throw new InvalidOperationException($"{Facts.GetCurrentMethodName()} operates on an await statement, and await statement not found.");
}
// assume, RequestAsync return is assigned to something (covered by other rule)
// 1: get 3rd type parameter in invocation
INamedTypeSymbol errorEventType, messageType, eventType;
Utilities.GetRequestAsyncInfo(requestAsyncMemberAccess, model, out messageType, out eventType, out errorEventType);
var generator = SyntaxGenerator.GetGenerator(document);
var exceptionArgumentsInfo = new Dictionary <string, TypeSyntax>
{
{ "ex", typeof(ReceivedErrorEventException <>).AsTypeSyntax(generator, errorEventType) }
};
return
(document.WithSyntaxRoot(Formatter.Format(
subjectToken.GetAncestorStatement().TryCatchSafe(exceptionArgumentsInfo,
generateCatchStatements,
root,
model), document.Project.Solution.Workspace, document.Project.Solution.Workspace.Options)));
}