private static bool InvocationIsAllowableValidateCall(InvocationExpressionSyntax invocation, SyntaxNodeAnalysisContext context)
{
if (invocation == null)
{
throw new ArgumentNullException(nameof(invocation));
}
var lastExpressionToken = invocation.Expression.GetLastToken();
if ((lastExpressionToken == null) || (lastExpressionToken.Text != "Validate"))
{
return(false);
}
var validateMethod = context.SemanticModel.GetSymbolInfo(invocation.Expression).Symbol as IMethodSymbol;
return
((validateMethod != null) &&
!validateMethod.Parameters.Any() &&
(validateMethod.Arity == 0) &&
validateMethod.ReturnsVoid &&
!CommonAnalyser.HasDisallowedAttribute(validateMethod));
}
private void LookForIllegalIAmImmutableImplementations(SyntaxNodeAnalysisContext context)
{
var classDeclaration = context.Node as ClassDeclarationSyntax;
if (classDeclaration == null)
{
return;
}
// Only bother looking this up (which is relatively expensive) if we know that we have to
var classImplementIAmImmutable = new Lazy <bool>(() => CommonAnalyser.ImplementsIAmImmutable(context.SemanticModel.GetDeclaredSymbol(classDeclaration)));
var publicMutableFields = classDeclaration.ChildNodes()
.OfType <FieldDeclarationSyntax>()
.Where(field => field.Modifiers.Any(modifier => modifier.IsKind(SyntaxKind.PublicKeyword)))
.Where(field => !field.Modifiers.Any(modifier => modifier.IsKind(SyntaxKind.ReadOnlyKeyword)));
foreach (var publicMutableField in publicMutableFields)
{
if (classImplementIAmImmutable.Value)
{
context.ReportDiagnostic(Diagnostic.Create(
MayNotHavePublicNonReadOnlyFieldsRule,
publicMutableField.GetLocation(),
string.Join(", ", publicMutableField.Declaration.Variables.Select(variable => variable.Identifier.Text))
));
}
}
// When the "With" methods updates create new instances, the existing instance is cloned and the target property updated - the constructor is not called on the
// new instance, which means that any validation in there is bypassed. I don't think that there's sufficient information available at runtime (in JavaScript) to
// create a new instance by calling the constructor instead of using this approach so, instead, validation is not allowed in the constructor - only "CtorSet"
// calls are acceptable with an optional "Validate" call that may appear at the end of the constructor. If this "Validate" method exists then it will be called
// after each "With" call in order to allow validation to be performed after each property update. The "Validate" method must have no parameters but may have
// any accessibility (private probably makes most sense).
var constructorsThatShouldUseValidateMethodIfClassImplementsIAmImmutable = new List <ConstructorDeclarationSyntax>();
var instanceConstructors = classDeclaration.ChildNodes()
.OfType <ConstructorDeclarationSyntax>()
.Where(constructor => (constructor.Body != null)) // If the code is in an invalid state then the Body property might be null - safe to ignore
.Where(constructor => !constructor.Modifiers.Any(modifier => modifier.Kind() == SyntaxKind.StaticKeyword));
foreach (var instanceConstructor in instanceConstructors)
{
var constructorShouldUseValidateMethodIfClassImplementsIAmImmutable = false;
var constructorChildNodes = instanceConstructor.Body.ChildNodes().ToArray();
foreach (var node in constructorChildNodes.Select((childNode, i) => new { Node = childNode, IsLastNode = i == (constructorChildNodes.Length - 1) }))
{
var expressionStatement = node.Node as ExpressionStatementSyntax;
if (expressionStatement == null)
{
constructorShouldUseValidateMethodIfClassImplementsIAmImmutable = true;
break;
}
var invocation = expressionStatement.Expression as InvocationExpressionSyntax;
if (invocation != null)
{
if (InvocationIsCtorSetCall(invocation, context) || (node.IsLastNode && InvocationIsAllowableValidateCall(invocation, context)))
{
continue;
}
}
constructorShouldUseValidateMethodIfClassImplementsIAmImmutable = true;
}
if (constructorShouldUseValidateMethodIfClassImplementsIAmImmutable)
{
constructorsThatShouldUseValidateMethodIfClassImplementsIAmImmutable.Add(instanceConstructor);
}
}
if (constructorsThatShouldUseValidateMethodIfClassImplementsIAmImmutable.Any())
{
if (classImplementIAmImmutable.Value)
{
foreach (var constructorThatShouldUseValidateMethod in constructorsThatShouldUseValidateMethodIfClassImplementsIAmImmutable)
{
context.ReportDiagnostic(Diagnostic.Create(
ConstructorWithLogicOtherThanCtorSetCallsShouldUseValidateMethod,
constructorThatShouldUseValidateMethod.GetLocation()
));
}
}
}
// If there is a Validate method that should be called and this constructor isn't calling it then warn
if (HasValidateMethodThatThisClassMustCall(classDeclaration))
{
var constructorsThatNeedToWarnAreNotCallingValidate = instanceConstructors
.Except(constructorsThatShouldUseValidateMethodIfClassImplementsIAmImmutable) // Don't warn about any constructors that are already being identified as needing attention
.Where(instanceConstructor =>
// If this constructors calls another of the constructor overloads then don't warn (only warn about constructors that DON'T call another overload)
(instanceConstructor.Initializer == null) || (instanceConstructor.Initializer.Kind() != SyntaxKind.ThisConstructorInitializer)
)
.Where(instanceConstructor =>
!instanceConstructor.Body.ChildNodes()
.OfType <ExpressionStatementSyntax>()
.Select(expressionStatement => expressionStatement.Expression as InvocationExpressionSyntax)
.Where(invocation => (invocation != null) && InvocationIsAllowableValidateCall(invocation, context))
.Any()
);
if (constructorsThatNeedToWarnAreNotCallingValidate.Any() && classImplementIAmImmutable.Value)
{
foreach (var constructorThatShouldUseValidateMethod in constructorsThatNeedToWarnAreNotCallingValidate)
{
context.ReportDiagnostic(Diagnostic.Create(
ConstructorDoesNotCallValidateMethod,
constructorThatShouldUseValidateMethod.GetLocation(),
classDeclaration.Identifier.Text
));
}
}
}
// This is likely to be the most expensive work (since it requires lookup of other symbols elsewhere in the solution, whereas the
// logic below only look at code in the current file) so only perform it when required (leave it as null until we absolutely need
// to know whether the current class implements IAmImmutable or not)
foreach (var property in classDeclaration.ChildNodes().OfType <PropertyDeclarationSyntax>())
{
if (property.ExplicitInterfaceSpecifier != null)
{
// Since CtorSet and With can not target properties that are not directly accessible through a reference to the
// IAmImmutable-implementing type (because "_ => _.Name" is acceptable as a property retriever but not something
// like "_ => ((IWhatever)_).Name") if a property is explicitly implemented for a base interface then the rules
// below need not be applied to it.
continue;
}
// If property.ExpressionBody is an ArrowExpressionClauseSyntax then it's C# 6 syntax for a read-only property that returns
// a value (which is different to a readonly auto-property, which introduces a backing field behind the scenes, this syntax
// doesn't introduce a new backing field, it returns an expression). In this case, there won't be an AccessorList (it will
// be null).
Diagnostic errorIfAny;
if (property.ExpressionBody is ArrowExpressionClauseSyntax)
{
errorIfAny = Diagnostic.Create(
MustHaveSettersOnPropertiesWithGettersAccessRule,
property.GetLocation(),
property.Identifier.Text
);
}
else
{
var getterIfDefined = property.AccessorList.Accessors.FirstOrDefault(a => a.Kind() == SyntaxKind.GetAccessorDeclaration);
var setterIfDefined = property.AccessorList.Accessors.FirstOrDefault(a => a.Kind() == SyntaxKind.SetAccessorDeclaration);
if ((getterIfDefined != null) && (setterIfDefined == null))
{
// If getterIfDefined is non-null but has a null Body then it's an auto-property getter, in which case not having
// a setter is allowed since it means that it's a read-only auto-property (for which Bridge will create a property
// setter for in the JavaScript)
if (getterIfDefined.Body != null)
{
errorIfAny = Diagnostic.Create(
MustHaveSettersOnPropertiesWithGettersAccessRule,
property.GetLocation(),
property.Identifier.Text
);
}
else
{
continue;
}
}
else if ((getterIfDefined != null) && CommonAnalyser.HasDisallowedAttribute(Microsoft.CodeAnalysis.CSharp.CSharpExtensions.GetDeclaredSymbol(context.SemanticModel, getterIfDefined)))
{
errorIfAny = Diagnostic.Create(
MayNotHaveBridgeAttributesOnPropertiesWithGettersAccessRule,
getterIfDefined.GetLocation(),
property.Identifier.Text
);
}
else if ((setterIfDefined != null) && CommonAnalyser.HasDisallowedAttribute(Microsoft.CodeAnalysis.CSharp.CSharpExtensions.GetDeclaredSymbol(context.SemanticModel, setterIfDefined)))
{
errorIfAny = Diagnostic.Create(
MayNotHaveBridgeAttributesOnPropertiesWithGettersAccessRule,
setterIfDefined.GetLocation(),
property.Identifier.Text
);
}
else if ((setterIfDefined != null) && IsPublic(property) && !IsPrivateOrProtected(setterIfDefined))
{
errorIfAny = Diagnostic.Create(
MayNotHavePublicSettersRule,
setterIfDefined.GetLocation(),
property.Identifier.Text
);
}
else
{
continue;
}
}
// Enountered a potential error if the current class implements IAmImmutable - so find out whether it does or not (if it
// doesn't then no further work is required and we can exit the entire process early)
if (!classImplementIAmImmutable.Value)
{
return;
}
context.ReportDiagnostic(errorIfAny);
}
}