public override async Task RegisterCodeFixesAsync(CodeFixContext context)
{
Diagnostic?diagnostic = context.Diagnostics.First();
SyntaxNode?root = await context.Document.GetSyntaxRootAsync(context.CancellationToken).ConfigureAwait(false);
var syntaxNode = (ExpressionSyntax)root.FindNode(diagnostic.Location.SourceSpan, getInnermostNodeForTie: true);
CSharpUtils.ContainingFunctionData container = CSharpUtils.GetContainingFunction(syntaxNode);
if (container.BlockOrExpression is null)
{
return;
}
SemanticModel?semanticModel = await context.Document.GetSemanticModelAsync(context.CancellationToken).ConfigureAwait(false);
ISymbol?enclosingSymbol = semanticModel.GetEnclosingSymbol(diagnostic.Location.SourceSpan.Start, context.CancellationToken);
if (enclosingSymbol is null)
{
return;
}
bool convertToAsync = !container.IsAsync && Utils.HasAsyncCompatibleReturnType(enclosingSymbol as IMethodSymbol);
if (convertToAsync)
{
// We don't support this yet, and we don't want to take the sync method path in this case.
// The user will have to fix this themselves.
return;
}
Regex lookupKey = (container.IsAsync || convertToAsync)
? CommonInterest.FileNamePatternForMethodsThatSwitchToMainThread
: CommonInterest.FileNamePatternForMethodsThatAssertMainThread;
string[] options = diagnostic.Properties[lookupKey.ToString()].Split('\n');
if (options.Length > 0)
{
// For any symbol lookups, we want to consider the position of the very first statement in the block.
int positionForLookup = container.BlockOrExpression.GetLocation().SourceSpan.Start + 1;
Lazy <ISymbol> cancellationTokenSymbol = new Lazy <ISymbol>(() => Utils.FindCancellationToken(semanticModel, positionForLookup, context.CancellationToken).FirstOrDefault());
foreach (var option in options)
{
// We're looking for methods that either require no parameters,
// or (if we have one to give) that have just one parameter that is a CancellationToken.
IMethodSymbol?proposedMethod = Utils.FindMethodGroup(semanticModel, option)
.FirstOrDefault(m => !m.Parameters.Any(p => !p.HasExplicitDefaultValue) ||
(cancellationTokenSymbol.Value is object && m.Parameters.Length == 1 && Utils.IsCancellationTokenParameter(m.Parameters[0])));
if (proposedMethod is null)
{
// We can't find it, so don't offer to use it.
continue;
}
if (proposedMethod.IsStatic)
{
OfferFix(option);
}
else
{
foreach (Tuple <bool, ISymbol>?candidate in Utils.FindInstanceOf(proposedMethod.ContainingType, semanticModel, positionForLookup, context.CancellationToken))
{
if (candidate.Item1)
{
OfferFix($"{candidate.Item2.Name}.{proposedMethod.Name}");
}
else
{
OfferFix($"{candidate.Item2.ContainingNamespace}.{candidate.Item2.ContainingType.Name}.{candidate.Item2.Name}.{proposedMethod.Name}");
}
}
}
void OfferFix(string fullyQualifiedMethod)
{
context.RegisterCodeFix(CodeAction.Create($"Add call to {fullyQualifiedMethod}", ct => Fix(fullyQualifiedMethod, proposedMethod, cancellationTokenSymbol), fullyQualifiedMethod), context.Diagnostics);
}
}
}
Task <Document> Fix(string fullyQualifiedMethod, IMethodSymbol methodSymbol, Lazy <ISymbol> cancellationTokenSymbol)
{
int typeAndMethodDelimiterIndex = fullyQualifiedMethod.LastIndexOf('.');
IdentifierNameSyntax methodName = SyntaxFactory.IdentifierName(fullyQualifiedMethod.Substring(typeAndMethodDelimiterIndex + 1));
ExpressionSyntax invokedMethod = CSharpUtils.MemberAccess(fullyQualifiedMethod.Substring(0, typeAndMethodDelimiterIndex).Split('.'), methodName);
InvocationExpressionSyntax?invocationExpression = SyntaxFactory.InvocationExpression(invokedMethod);
IParameterSymbol? cancellationTokenParameter = methodSymbol.Parameters.FirstOrDefault(Utils.IsCancellationTokenParameter);
if (cancellationTokenParameter is object && cancellationTokenSymbol.Value is object)
{
ArgumentSyntax?arg = SyntaxFactory.Argument(SyntaxFactory.IdentifierName(cancellationTokenSymbol.Value.Name));
if (methodSymbol.Parameters.IndexOf(cancellationTokenParameter) > 0)
{
arg = arg.WithNameColon(SyntaxFactory.NameColon(SyntaxFactory.IdentifierName(cancellationTokenParameter.Name)));
}
invocationExpression = invocationExpression.AddArgumentListArguments(arg);
}
ExpressionSyntax? awaitExpression = container.IsAsync ? SyntaxFactory.AwaitExpression(invocationExpression) : null;
ExpressionStatementSyntax?addedStatement = SyntaxFactory.ExpressionStatement(awaitExpression ?? invocationExpression)
.WithAdditionalAnnotations(Simplifier.Annotation, Formatter.Annotation);
var initialBlockSyntax = container.BlockOrExpression as BlockSyntax;
if (initialBlockSyntax is null)
{
SyntaxToken openBrace = SyntaxFactory.Token(SyntaxFactory.TriviaList(), SyntaxKind.OpenBraceToken, SyntaxFactory.TriviaList(SyntaxFactory.EndOfLine("\r\n")));
SyntaxToken closeBrace = SyntaxFactory.Token(SyntaxKind.CloseBraceToken);
SyntaxList <StatementSyntax> statementList = SyntaxFactory.List <StatementSyntax>(new[] { SyntaxFactory.ReturnStatement((ExpressionSyntax)container.BlockOrExpression) });
initialBlockSyntax = SyntaxFactory.Block(openBrace, statementList, closeBrace)
.WithAdditionalAnnotations(Formatter.Annotation);
}
BlockSyntax?newBlock = initialBlockSyntax.WithStatements(initialBlockSyntax.Statements.Insert(0, addedStatement));
return(Task.FromResult(context.Document.WithSyntaxRoot(root.ReplaceNode(container.BlockOrExpression.Parent, container.BodyReplacement(newBlock)))));
}
}
public override async Task RegisterCodeFixesAsync(CodeFixContext context)
{
foreach (var diagnostic in context.Diagnostics)
{
var root = await context.Document.GetSyntaxRootAsync(context.CancellationToken).ConfigureAwait(false);
ExpressionSyntax?syntaxNode = root.FindNode(diagnostic.Location.SourceSpan, getInnermostNodeForTie: true) as ExpressionSyntax;
if (syntaxNode is null)
{
continue;
}
var container = CSharpUtils.GetContainingFunction(syntaxNode);
if (container.BlockOrExpression == null)
{
return;
}
if (!container.IsAsync)
{
if (!(container.Function is MethodDeclarationSyntax || container.Function is AnonymousFunctionExpressionSyntax))
{
// We don't support converting whatever this is into an async method.
return;
}
}
var semanticModel = await context.Document.GetSemanticModelAsync(context.CancellationToken).ConfigureAwait(false);
var enclosingSymbol = semanticModel.GetEnclosingSymbol(diagnostic.Location.SourceSpan.Start, context.CancellationToken);
if (enclosingSymbol == null)
{
return;
}
var hasReturnValue = ((enclosingSymbol as IMethodSymbol)?.ReturnType as INamedTypeSymbol)?.IsGenericType ?? false;
var options = await CommonFixes.ReadMethodsAsync(context, CommonInterest.FileNamePatternForMethodsThatSwitchToMainThread, context.CancellationToken);
int positionForLookup = diagnostic.Location.SourceSpan.Start;
ISymbol cancellationTokenSymbol = Utils.FindCancellationToken(semanticModel, positionForLookup, context.CancellationToken).FirstOrDefault();
foreach (var option in options)
{
// We're looking for methods that either require no parameters,
// or (if we have one to give) that have just one parameter that is a CancellationToken.
var proposedMethod = Utils.FindMethodGroup(semanticModel, option)
.FirstOrDefault(m => !m.Parameters.Any(p => !p.HasExplicitDefaultValue) ||
(cancellationTokenSymbol != null && m.Parameters.Length == 1 && Utils.IsCancellationTokenParameter(m.Parameters[0])));
if (proposedMethod == null)
{
// We can't find it, so don't offer to use it.
continue;
}
if (proposedMethod.IsStatic)
{
OfferFix(option.ToString());
}
else
{
foreach (var candidate in Utils.FindInstanceOf(proposedMethod.ContainingType, semanticModel, positionForLookup, context.CancellationToken))
{
if (candidate.Item1)
{
OfferFix($"{candidate.Item2.Name}.{proposedMethod.Name}");
}
else
{
OfferFix($"{candidate.Item2.ContainingNamespace}.{candidate.Item2.ContainingType.Name}.{candidate.Item2.Name}.{proposedMethod.Name}");
}
}
}
void OfferFix(string fullyQualifiedMethod)
{
context.RegisterCodeFix(CodeAction.Create($"Use 'await {fullyQualifiedMethod}'", ct => Fix(fullyQualifiedMethod, proposedMethod, hasReturnValue, ct), fullyQualifiedMethod), context.Diagnostics);
}
}
async Task <Solution> Fix(string fullyQualifiedMethod, IMethodSymbol methodSymbol, bool hasReturnValue, CancellationToken cancellationToken)
{
var assertionStatementToRemove = syntaxNode !.FirstAncestorOrSelf <StatementSyntax>();
int typeAndMethodDelimiterIndex = fullyQualifiedMethod.LastIndexOf('.');
IdentifierNameSyntax methodName = SyntaxFactory.IdentifierName(fullyQualifiedMethod.Substring(typeAndMethodDelimiterIndex + 1));
ExpressionSyntax invokedMethod = CSharpUtils.MemberAccess(fullyQualifiedMethod.Substring(0, typeAndMethodDelimiterIndex).Split('.'), methodName)
.WithAdditionalAnnotations(Simplifier.Annotation);
var invocationExpression = SyntaxFactory.InvocationExpression(invokedMethod);
var cancellationTokenParameter = methodSymbol.Parameters.FirstOrDefault(Utils.IsCancellationTokenParameter);
if (cancellationTokenParameter != null && cancellationTokenSymbol != null)
{
var arg = SyntaxFactory.Argument(SyntaxFactory.IdentifierName(cancellationTokenSymbol.Name));
if (methodSymbol.Parameters.IndexOf(cancellationTokenParameter) > 0)
{
arg = arg.WithNameColon(SyntaxFactory.NameColon(SyntaxFactory.IdentifierName(cancellationTokenParameter.Name)));
}
invocationExpression = invocationExpression.AddArgumentListArguments(arg);
}
ExpressionSyntax awaitExpression = SyntaxFactory.AwaitExpression(invocationExpression);
var addedStatement = SyntaxFactory.ExpressionStatement(awaitExpression)
.WithAdditionalAnnotations(Simplifier.Annotation, Formatter.Annotation);
var methodAnnotation = new SyntaxAnnotation();
CSharpSyntaxNode methodSyntax = container.Function.ReplaceNode(assertionStatementToRemove, addedStatement)
.WithAdditionalAnnotations(methodAnnotation);
Document newDocument = context.Document.WithSyntaxRoot(root.ReplaceNode(container.Function, methodSyntax));
var newSyntaxRoot = await newDocument.GetSyntaxRootAsync(cancellationToken);
methodSyntax = (CSharpSyntaxNode)newSyntaxRoot.GetAnnotatedNodes(methodAnnotation).Single();
if (!container.IsAsync)
{
switch (methodSyntax)
{
case AnonymousFunctionExpressionSyntax anonFunc:
semanticModel = await newDocument.GetSemanticModelAsync(cancellationToken);
methodSyntax = FixUtils.MakeMethodAsync(anonFunc, hasReturnValue, semanticModel, cancellationToken);
newDocument = newDocument.WithSyntaxRoot(newSyntaxRoot.ReplaceNode(anonFunc, methodSyntax));
break;
case MethodDeclarationSyntax methodDecl:
(newDocument, methodSyntax) = await FixUtils.MakeMethodAsync(methodDecl, newDocument, cancellationToken);
break;
}
}
return(newDocument.Project.Solution);
}
}
}