private AnalyzationCandidateResult AnalyzeAsyncCandidates(BodyFunctionDataReference functionReferenceData, IEnumerable <IMethodSymbol> asyncCandidates, bool preferCancellationToken)
{
var orderedCandidates = preferCancellationToken
? asyncCandidates.OrderBy(o => o, MethodCancellationTokenComparer.Instance).ToList()
: asyncCandidates.OrderByDescending(o => o, MethodCancellationTokenComparer.Instance).ToList();
if (orderedCandidates.Count == 0)
{
return(new AnalyzationCandidateResult
{
AsyncCandidate = null,
CanBeAsync = false,
IgnoreBodyFunctionDataReferenceReason = IgnoreReason.NoAsyncCounterparts
});
}
// More than one
// By default we will get here when there are multiple overloads of an async function (e.g. Task.Run<T>(Func<T>, CancellationToken) and Task.Run<T>(Func<Task<T>>, CancellationToken))
// In the Task.Run case we have to check the delegate argument if it can be async or not (the delegate argument will be processed before the invocation)
//if (functionReferenceData.DelegateArguments == null)
//{
// return new AnalyzationCandidateResult
// {
// AsyncCandidate = null,
// CanBeAsync = false,
// IgnoreBodyFunctionDataReferenceReason = IgnoreReason.Custom("Multiple async counterparts without delegate arguments.", DiagnosticSeverity.Info)
// };
//}
var validCandidates = new List <AnalyzationCandidateResult>();
foreach (var asyncCandidate in orderedCandidates)
{
var result = AnalyzeAsyncCandidate(functionReferenceData, asyncCandidate, preferCancellationToken);
if (result.AsyncCandidate != null)
{
validCandidates.Add(result);
}
}
if (validCandidates.Count == 0)
{
return(new AnalyzationCandidateResult
{
AsyncCandidate = null,
CanBeAsync = false,
IgnoreBodyFunctionDataReferenceReason = IgnoreReason.Custom("No async counterparts matches delegate arguments.", DiagnosticSeverity.Info)
});
}
return(validCandidates[0]);
}
private IMethodSymbol FindAsyncCandidate(BodyFunctionDataReference functionReferenceData, IList <IMethodSymbol> asyncCandidates)
{
if (asyncCandidates.Count == 0)
{
return(null);
}
if (asyncCandidates.Count == 1)
{
return(asyncCandidates[0]);
}
// More than one
// By default we will get here when there are multiple overloads of an async function (e.g. Task.Run<T>(Func<T>, CancellationToken) and Task.Run<T>(Func<Task<T>>, CancellationToken))
// In the Task.Run case we have to check the delegate argument if it can be asnyc or not (the delegate argument will be processed before the invocation)
if (!functionReferenceData.DelegateArguments.Any())
{
functionReferenceData.Ignore(IgnoreReason.Custom("Multiple async counterparts without delegate arguments.", DiagnosticSeverity.Info));
return(null);
}
foreach (var functionArgument in functionReferenceData.DelegateArguments)
{
var funcData = functionArgument.FunctionData;
if (funcData != null) // Anonymous function as argument
{
if (funcData.BodyFunctionReferences.All(o => o.GetConversion() != ReferenceConversion.ToAsync))
{
return(null);
}
CalculatePreserveReturnType(funcData);
var validOverloads = new List <IMethodSymbol>();
foreach (var tokenOverload in asyncCandidates)
{
// Check if the return type of the delegate parameter matches with the calculated return type of the anonymous function
var delegateSymbol = (IMethodSymbol)tokenOverload.Parameters[functionArgument.Index].Type.GetMembers("Invoke").First();
if (
(delegateSymbol.ReturnType.IsTaskType() && !funcData.PreserveReturnType) ||
(!delegateSymbol.ReturnType.IsTaskType() && funcData.PreserveReturnType && !funcData.Symbol.ReturnType.IsTaskType())
)
{
validOverloads.Add(tokenOverload);
}
}
asyncCandidates = validOverloads;
}
else
{
// TODO
return(null);
}
}
return(asyncCandidates[0]);
}
private bool IgnoreIfInvalidAncestor(SyntaxNode node, SyntaxNode endNode, BodyFunctionDataReference functionReferenceData)
{
var currAncestor = node.Parent;
while (!currAncestor.Equals(endNode))
{
if (currAncestor.IsKind(SyntaxKind.QueryExpression))
{
functionReferenceData.Ignore(IgnoreReason.Custom("Cannot await async method in a query expression", DiagnosticSeverity.Info));
return(true);
}
currAncestor = currAncestor.Parent;
}
return(false);
}
private AnalyzationCandidateResult AnalyzeAsyncCandidate(BodyFunctionDataReference functionReferenceData,
IMethodSymbol asyncCandidate, bool useCancellationToken)
{
var canBeAsync = true;
var asnycDelegateIndexes = functionReferenceData.ReferenceSymbol.GetAsyncDelegateArgumentIndexes(asyncCandidate);
if (asnycDelegateIndexes != null)
{
if (asnycDelegateIndexes.Count == 0 && functionReferenceData.DelegateArguments != null)
{
return(new AnalyzationCandidateResult
{
AsyncCandidate = asyncCandidate,
CanBeAsync = true,
IgnoreDelegateArgumentsReason =
IgnoreReason.Custom("Argument is not async.", DiagnosticSeverity.Hidden)
});
}
if (asnycDelegateIndexes.Count > 0 && functionReferenceData.DelegateArguments == null)
{
return(new AnalyzationCandidateResult
{
AsyncCandidate = null,
CanBeAsync = false,
IgnoreBodyFunctionDataReferenceReason =
IgnoreReason.Custom("Delegate argument is not async.", DiagnosticSeverity.Hidden)
});
}
}
if (functionReferenceData.DelegateArguments == null)
{
return(new AnalyzationCandidateResult
{
AsyncCandidate = asyncCandidate,
CanBeAsync = true
});
}
if (asnycDelegateIndexes != null)
{
var delegateIndexes = functionReferenceData.DelegateArguments.Select(o => o.Index).ToList();
if (delegateIndexes.Count != asnycDelegateIndexes.Count ||
asnycDelegateIndexes.Any(o => !delegateIndexes.Contains(o)))
{
return(new AnalyzationCandidateResult
{
AsyncCandidate = null,
CanBeAsync = false,
IgnoreBodyFunctionDataReferenceReason =
IgnoreReason.Custom("Delegate arguments do not match with the async counterpart.", DiagnosticSeverity.Hidden)
});
}
}
foreach (var functionArgument in functionReferenceData.DelegateArguments)
{
var funcData = functionArgument.FunctionData;
if (funcData == null)
{
var bodyRef = functionArgument.FunctionReference;
funcData = bodyRef.ReferenceFunctionData;
//if (!result.CanBeAsync)
//{
// return new AnalyzationCandidateResult
// {
// AsyncCandidate = null,
// CanBeAsync = false,
// IgnoreBodyFunctionDataReferenceReason =
// IgnoreReason.Custom("Delegate argument cannot be async.", DiagnosticSeverity.Hidden)
// };
//}
if (funcData == null)
{
var result = AnalyzeAsyncCandidates(bodyRef, bodyRef.ReferenceAsyncSymbols.ToList(), useCancellationToken);
if (result.AsyncCandidate != null && functionArgument.Index < asyncCandidate.Parameters.Length)
{
var delegateSymbol = (IMethodSymbol)asyncCandidate.Parameters[functionArgument.Index].Type.GetMembers("Invoke").First();
if (!delegateSymbol.MatchesDefinition(result.AsyncCandidate, true))
{
return(new AnalyzationCandidateResult
{
AsyncCandidate = null,
CanBeAsync = false,
IgnoreBodyFunctionDataReferenceReason =
IgnoreReason.Custom("Delegate argument async counterpart does not match.", DiagnosticSeverity.Hidden)
});
}
}
continue;
}
}
if (funcData.BodyFunctionReferences.All(o => o.GetConversion() == ReferenceConversion.Ignore))
{
return(new AnalyzationCandidateResult
{
AsyncCandidate = null,
CanBeAsync = false,
IgnoreBodyFunctionDataReferenceReason =
IgnoreReason.Custom("The delegate argument does not have any async invocation.", DiagnosticSeverity.Hidden)
});
}
canBeAsync &= funcData.BodyFunctionReferences.Any(o => o.GetConversion() == ReferenceConversion.ToAsync);
//if (funcData.Symbol.MethodKind != MethodKind.AnonymousFunction)
//{
// CalculatePreserveReturnType(funcData);
//}
//// Check if the return type of the delegate parameter matches with the calculated return type of the anonymous function
//if (
// (delegateSymbol.ReturnType.SupportsTaskType() && !funcData.PreserveReturnType) ||
// (!delegateSymbol.ReturnType.SupportsTaskType() && funcData.PreserveReturnType && !funcData.Symbol.ReturnType.SupportsTaskType())
//)
//{
// continue;
//}
//return new AnalyzationCandidateResult
//{
// AsyncCandidate = null,
// CanBeAsync = false,
// IgnoreBodyFunctionDataReferenceReason =
// IgnoreReason.Custom("Return type of the delegate argument does not match.", DiagnosticSeverity.Hidden)
//};
}
return(new AnalyzationCandidateResult
{
AsyncCandidate = asyncCandidate,
CanBeAsync = canBeAsync
});
}
private void AnalyzeInvocationExpression(DocumentData documentData, InvocationExpressionSyntax node, BodyFunctionDataReference functionReferenceData)
{
var functionData = functionReferenceData.Data;
var methodSymbol = functionReferenceData.ReferenceSymbol;
var functionNode = functionData.GetNode();
if (IgnoreIfInvalidAncestor(node, functionNode, functionReferenceData))
{
return;
}
// If the invocation returns a Task then we need to analyze it further to see how the Task is handled
if (methodSymbol.ReturnType.IsTaskType())
{
var retrunType = (INamedTypeSymbol)methodSymbol.ReturnType;
var canBeAwaited = false;
var currNode = node.Parent;
while (true)
{
var memberExpression = currNode as MemberAccessExpressionSyntax;
if (memberExpression == null)
{
break;
}
var memberName = memberExpression.Name.ToString();
if (retrunType.IsGenericType && memberName == "Result")
{
canBeAwaited = true;
break;
}
if (memberName == "ConfigureAwait")
{
var invocationNode = currNode.Parent as InvocationExpressionSyntax;
if (invocationNode != null)
{
functionReferenceData.ConfigureAwaitParameter = invocationNode.ArgumentList.Arguments.First().Expression;
currNode = invocationNode.Parent;
continue;
}
break;
}
if (memberName == "GetAwaiter")
{
var invocationNode = currNode.Parent as InvocationExpressionSyntax;
if (invocationNode != null)
{
currNode = invocationNode.Parent;
continue;
}
break;
}
if (_taskResultMethods.Contains(memberName))
{
var invocationNode = currNode.Parent as InvocationExpressionSyntax;
if (invocationNode != null)
{
canBeAwaited = true;
}
}
break;
}
if (!canBeAwaited)
{
functionReferenceData.AwaitInvocation = false;
functionReferenceData.AddDiagnostic("Cannot await invocation that returns a Task without being synchronously awaited", DiagnosticSeverity.Info);
}
else
{
functionReferenceData.SynchronouslyAwaited = true;
}
}
if (node.Expression is SimpleNameSyntax)
{
functionReferenceData.InvokedFromType = functionData.Symbol.ContainingType;
}
else if (node.Expression is MemberAccessExpressionSyntax memberAccessExpression)
{
functionReferenceData.InvokedFromType = documentData.SemanticModel.GetTypeInfo(memberAccessExpression.Expression).Type;
}
FindAsyncCounterparts(functionReferenceData);
var delegateParams = methodSymbol.Parameters.Select(o => o.Type.TypeKind == TypeKind.Delegate).ToList();
for (var i = 0; i < node.ArgumentList.Arguments.Count; i++)
{
var argument = node.ArgumentList.Arguments[i];
var argumentExpression = argument.Expression;
// We have to process anonymous funcions as they will not be analyzed as arguments
if (argumentExpression.IsFunction())
{
var anonFunction = (AnonymousFunctionData)functionData.ChildFunctions[argumentExpression];
functionReferenceData.AddDelegateArgument(new DelegateArgumentData(anonFunction, i));
anonFunction.ArgumentOfFunctionInvocation = functionReferenceData;
continue;
}
if (argumentExpression.IsKind(SyntaxKind.IdentifierName) ||
argumentExpression.IsKind(SyntaxKind.SimpleMemberAccessExpression))
{
var argRefFunction = functionData.BodyFunctionReferences.FirstOrDefault(o => argument.Equals(o.ReferenceNode));
if (argRefFunction == null)
{
// Ignore only if the async argument does not match
// TODO: internal methods, unify with CalculateFunctionArguments
if (functionReferenceData.ReferenceFunctionData == null && delegateParams[i]) // If the parameter is a delegate check the symbol of the argument
{
var argSymbol = documentData.SemanticModel.GetSymbolInfo(argumentExpression).Symbol;
if (argSymbol is ILocalSymbol arglocalSymbol)
{
// TODO: local arguments
functionReferenceData.Ignore(IgnoreReason.NotSupported("Local delegate arguments are currently not supported"));
return;
}
if (argSymbol is IMethodSymbol argMethodSymbol)
{
// TODO: support custom async counterparts that have different parameters
// If the invocation has at least one argument that does not fit into any async counterparts we have to ignore it
if (functionReferenceData.ReferenceAsyncSymbols
.Where(o => o.Parameters.Length >= methodSymbol.Parameters.Length) // The async counterpart may have less parameters. e.g. Parallel.For -> Task.WhenAll
.All(o => !((IMethodSymbol)o.Parameters[i].Type.GetMembers("Invoke").First()).ReturnType.Equals(argMethodSymbol.ReturnType)))
{
functionReferenceData.Ignore(IgnoreReason.Custom("The delegate argument does not fit to any async counterparts", DiagnosticSeverity.Hidden));
return;
}
}
}
continue;
}
functionReferenceData.AddDelegateArgument(new DelegateArgumentData(argRefFunction, i));
argRefFunction.ArgumentOfFunctionInvocation = functionReferenceData;
}
}
SetAsyncCounterpart(functionReferenceData);
CalculateLastInvocation(node, functionReferenceData);
foreach (var analyzer in _configuration.InvocationExpressionAnalyzers)
{
analyzer.AnalyzeInvocationExpression(node, functionReferenceData, documentData.SemanticModel);
}
PropagateCancellationToken(functionReferenceData);
}
private void AnalyzeMethodReference(DocumentData documentData, BodyFunctionDataReference refData)
{
var nameNode = refData.ReferenceNameNode;
// Find the actual usage of the method
SyntaxNode currNode = nameNode;
var ascend = true;
if (refData.ReferenceSymbol.IsPropertyAccessor())
{
ascend = false;
AnalyzeAccessor(documentData, nameNode, refData);
}
else
{
currNode = nameNode.Parent;
}
while (ascend)
{
ascend = false;
switch (currNode.Kind())
{
case SyntaxKind.ConditionalExpression:
break;
case SyntaxKind.InvocationExpression:
AnalyzeInvocationExpression(documentData, (InvocationExpressionSyntax)currNode, refData);
break;
case SyntaxKind.Argument:
AnalyzeArgumentExpression((ArgumentSyntax)currNode, nameNode, refData);
break;
case SyntaxKind.AddAssignmentExpression:
refData.Ignore(IgnoreReason.Custom(
$"Cannot attach an async method to an event (void async is not an option as cannot be awaited)", DiagnosticSeverity.Info));
break;
case SyntaxKind.SubtractAssignmentExpression:
refData.Ignore(IgnoreReason.Custom($"Cannot detach an async method to an event", DiagnosticSeverity.Info));
break;
case SyntaxKind.VariableDeclaration:
refData.Ignore(IgnoreReason.NotSupported($"Assigning async method to a variable is not supported"));
break;
case SyntaxKind.CastExpression:
refData.AwaitInvocation = true;
ascend = true;
break;
case SyntaxKind.ReturnStatement:
break;
case SyntaxKind.ArrayInitializerExpression:
case SyntaxKind.CollectionInitializerExpression:
case SyntaxKind.ComplexElementInitializerExpression:
refData.Ignore(IgnoreReason.NotSupported($"Async method inside an array/collection initializer is not supported"));
break;
// skip
case SyntaxKind.VariableDeclarator:
case SyntaxKind.EqualsValueClause:
case SyntaxKind.SimpleMemberAccessExpression:
case SyntaxKind.ArgumentList:
case SyntaxKind.ObjectCreationExpression:
case SyntaxKind.MemberBindingExpression: // ?.
ascend = true;
break;
default:
throw new NotSupportedException(
$"Unknown node kind: {currNode.Kind()} at {currNode?.SyntaxTree.GetLineSpan(currNode.Span)}. Node:{Environment.NewLine}{currNode}");
}
if (ascend)
{
currNode = currNode.Parent;
}
}
refData.ReferenceNode = currNode;
if (!refData.AwaitInvocation.HasValue)
{
refData.AwaitInvocation = refData.Conversion != ReferenceConversion.Ignore;
}
}
