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' Licensed to the .NET Foundation under one or more agreements.
' The .NET Foundation licenses this file to you under the MIT license.
' See the LICENSE file in the project root for more information.
Imports System.Collections.Immutable
Imports System.Composition
Imports System.Diagnostics.CodeAnalysis
Imports System.Threading
Imports Microsoft.CodeAnalysis.CodeActions
Imports Microsoft.CodeAnalysis.CodeFixes
Imports Microsoft.CodeAnalysis.CodeGeneration
Imports Microsoft.CodeAnalysis.FindSymbols
Imports Microsoft.CodeAnalysis.LanguageService
Imports Microsoft.CodeAnalysis.VisualBasic.Syntax
Namespace Microsoft.CodeAnalysis.VisualBasic.CodeFixes.GenerateEvent
<ExportCodeFixProvider(LanguageNames.VisualBasic, Name:=PredefinedCodeFixProviderNames.GenerateEvent), [Shared]>
<ExtensionOrder(After:=PredefinedCodeFixProviderNames.GenerateEnumMember)>
Partial Friend Class GenerateEventCodeFixProvider
Inherits CodeFixProvider
Friend Const BC30401 As String = "BC30401" ' error BC30401: 'goo' cannot implement 'E' because there is no matching event on interface 'MyInterface'.
Friend Const BC30590 As String = "BC30590" ' error BC30590: Event 'MyEvent' cannot be found.
Friend Const BC30456 As String = "BC30456" ' error BC30456: 'x' is not a member of 'y'.
Friend Const BC30451 As String = "BC30451" ' error BC30451: 'x' is not declared, it may be inaccessible due to its protection level.
<ImportingConstructor>
<SuppressMessage("RoslynDiagnosticsReliability", "RS0033:Importing constructor should be [Obsolete]", Justification:="Used in test code: https://github.com/dotnet/roslyn/issues/42814")>
Public Sub New()
End Sub
Public NotOverridable Overrides ReadOnly Property FixableDiagnosticIds As ImmutableArray(Of String)
Get
Return ImmutableArray.Create(BC30401, BC30590, BC30456, BC30451)
End Get
End Property
Public Overrides Function GetFixAllProvider() As FixAllProvider
' Fix All is not supported by this code fix
' https://github.com/dotnet/roslyn/issues/34474
Return Nothing
End Function
Public NotOverridable Overrides Async Function RegisterCodeFixesAsync(context As CodeFixContext) As Task
Dim root = Await context.Document.GetSyntaxRootAsync(context.CancellationToken).ConfigureAwait(False)
Dim token = root.FindToken(context.Span.Start)
If Not token.Span.IntersectsWith(context.Span) Then
Return
End If
Dim result As CodeAction = Nothing
For Each node In token.GetAncestors(Of SyntaxNode).Where(Function(c) c.Span.IntersectsWith(context.Span) AndAlso IsCandidate(c))
Dim qualifiedName = TryCast(node, QualifiedNameSyntax)
If qualifiedName IsNot Nothing Then
result = Await GenerateEventFromImplementsAsync(context.Document, qualifiedName, context.CancellationToken).ConfigureAwait(False)
End If
Dim handlesClauseItem = TryCast(node, HandlesClauseItemSyntax)
If handlesClauseItem IsNot Nothing Then
result = Await GenerateEventFromHandlesAsync(context.Document, handlesClauseItem, context.CancellationToken).ConfigureAwait(False)
End If
Dim handlerStatement = TryCast(node, AddRemoveHandlerStatementSyntax)
If handlerStatement IsNot Nothing Then
result = Await GenerateEventFromAddRemoveHandlerAsync(context.Document, handlerStatement, context.CancellationToken).ConfigureAwait(False)
End If
If result IsNot Nothing Then
context.RegisterCodeFix(result, context.Diagnostics)
Return
End If
Next
End Function
Private Shared Async Function GenerateEventFromAddRemoveHandlerAsync(document As Document, handlerStatement As AddRemoveHandlerStatementSyntax, cancellationToken As CancellationToken) As Task(Of CodeAction)
Dim semanticModel = Await document.GetSemanticModelAsync(cancellationToken).ConfigureAwait(False)
Dim handlerExpression = GetHandlerExpression(handlerStatement)
Dim delegateSymbol As IMethodSymbol = Nothing
If Not TryGetDelegateSymbol(handlerExpression, semanticModel, delegateSymbol, cancellationToken) Then
Return Nothing
End If
Dim eventExpression = handlerStatement.EventExpression
Dim eventSymbol = semanticModel.GetSymbolInfo(eventExpression, cancellationToken).GetAnySymbol()
If eventSymbol IsNot Nothing Then
Return Nothing
End If
Dim containingSymbol = semanticModel.GetEnclosingNamedType(handlerStatement.SpanStart, cancellationToken)
If containingSymbol Is Nothing Then
Return Nothing
End If
Dim targetType As INamedTypeSymbol = Nothing
Dim actualEventName As String = Nothing
If Not TryGetNameAndTargetType(eventExpression, containingSymbol, semanticModel, targetType, actualEventName, cancellationToken) Then
Return Nothing
End If
If Not ResolveTargetType(targetType, semanticModel) Then
Return Nothing
End If
' Target type may be in other project so we need to find its source definition
Dim sourceDefinition = SymbolFinder.FindSourceDefinition(targetType, document.Project.Solution, cancellationToken)
targetType = TryCast(sourceDefinition, INamedTypeSymbol)
If targetType Is Nothing Then
Return Nothing
End If
Return Await GenerateCodeActionAsync(document, semanticModel, delegateSymbol, actualEventName, targetType, cancellationToken).ConfigureAwait(False)
End Function
Private Shared Async Function GenerateCodeActionAsync(
document As Document,
semanticModel As SemanticModel,
delegateSymbol As IMethodSymbol,
actualEventName As String,
targetType As INamedTypeSymbol,
cancellationToken As CancellationToken) As Task(Of CodeAction)
Dim codeGenService = document.Project.Solution.Services.GetLanguageServices(targetType.Language).GetService(Of ICodeGenerationService)
Dim syntaxFactService = document.Project.Solution.Services.GetLanguageServices(targetType.Language).GetService(Of ISyntaxFactsService)
Dim eventHandlerName As String = actualEventName + "Handler"
Dim existingSymbols = Await DeclarationFinder.FindSourceDeclarationsWithNormalQueryAsync(
document.Project.Solution, eventHandlerName, Not syntaxFactService.IsCaseSensitive, SymbolFilter.Type, cancellationToken).ConfigureAwait(False)
If existingSymbols.Any(Function(existingSymbol) existingSymbol IsNot Nothing _
AndAlso Equals(existingSymbol.ContainingNamespace, targetType.ContainingNamespace)) Then
' There already exists a delegate that matches the event handler name
Return Nothing
End If
' We also need to generate the delegate type
Dim delegateType = CodeGenerationSymbolFactory.CreateDelegateTypeSymbol(
attributes:=Nothing, accessibility:=Accessibility.Public, modifiers:=Nothing,
returnType:=semanticModel.Compilation.GetSpecialType(SpecialType.System_Void),
refKind:=RefKind.None, name:=eventHandlerName,
parameters:=delegateSymbol.GetParameters())
Dim generatedEvent = CodeGenerationSymbolFactory.CreateEventSymbol(
attributes:=ImmutableArray(Of AttributeData).Empty,
accessibility:=Accessibility.Public, modifiers:=Nothing,
explicitInterfaceImplementations:=Nothing,
type:=delegateType, name:=actualEventName)
' Point the delegate back at the event symbol. This way the generators know to generate parameters
' instead of an 'As' clause.
delegateType.AssociatedSymbol = generatedEvent
Return New GenerateEventCodeAction(document.Project.Solution, targetType, generatedEvent, codeGenService)
End Function
Private Shared Function GetHandlerExpression(handlerStatement As AddRemoveHandlerStatementSyntax) As ExpressionSyntax
Dim unaryExpression = TryCast(handlerStatement.DelegateExpression.DescendantNodesAndSelf().Where(Function(n) n.IsKind(SyntaxKind.AddressOfExpression)).FirstOrDefault, UnaryExpressionSyntax)
If unaryExpression Is Nothing Then
Return handlerStatement.DelegateExpression
Else
Return unaryExpression.Operand
End If
End Function
Private Shared Function TryGetDelegateSymbol(handlerExpression As ExpressionSyntax, semanticModel As SemanticModel, ByRef delegateSymbol As IMethodSymbol, cancellationToken As CancellationToken) As Boolean
delegateSymbol = TryCast(semanticModel.GetSymbolInfo(handlerExpression, cancellationToken).GetAnySymbol(), IMethodSymbol)
If delegateSymbol Is Nothing Then
Dim typeSymbol = TryCast(semanticModel.GetTypeInfo(handlerExpression, cancellationToken).Type, INamedTypeSymbol)
If typeSymbol IsNot Nothing AndAlso typeSymbol.DelegateInvokeMethod IsNot Nothing Then
delegateSymbol = typeSymbol.DelegateInvokeMethod
Else
Return False
End If
End If
If delegateSymbol.Arity <> 0 AndAlso delegateSymbol.TypeArguments.Any(Function(n) n.TypeKind = TypeKind.TypeParameter) Then
Return False
End If
Return True
End Function
Private Shared Function ResolveTargetType(ByRef targetType As INamedTypeSymbol, semanticModel As SemanticModel) As Boolean
If targetType Is Nothing OrElse
Not (targetType.TypeKind = TypeKind.Class OrElse targetType.TypeKind = TypeKind.Interface) OrElse
targetType.IsAnonymousType Then
Return False
End If
targetType = DirectCast(targetType.GetSymbolKey().Resolve(semanticModel.Compilation).Symbol, INamedTypeSymbol)
If targetType Is Nothing Then
Return False
End If
Return True
End Function
Private Shared Function TryGetNameAndTargetType(eventExpression As ExpressionSyntax, containingSymbol As INamedTypeSymbol, semanticModel As SemanticModel, ByRef targetType As INamedTypeSymbol, ByRef actualEventName As String, cancellationToken As CancellationToken) As Boolean
Dim eventType As INamedTypeSymbol = Nothing
If TypeOf eventExpression Is IdentifierNameSyntax Then
actualEventName = CType(eventExpression, IdentifierNameSyntax).Identifier.ValueText
ElseIf TypeOf eventExpression Is MemberAccessExpressionSyntax Then
Dim memberAccess = CType(eventExpression, MemberAccessExpressionSyntax)
Dim qualifier As ExpressionSyntax = Nothing
Dim arity As Integer
memberAccess.DecomposeName(qualifier, actualEventName, arity)
eventType = TryCast(semanticModel.GetTypeInfo(qualifier, cancellationToken).Type, INamedTypeSymbol)
Else
Return False
End If
If eventExpression.DescendantTokens().Where(Function(n) n.IsKind(SyntaxKind.MeKeyword, SyntaxKind.MyClassKeyword)).Any Then
targetType = containingSymbol
Return True
ElseIf eventExpression.DescendantTokens().Where(Function(n) n.IsKind(SyntaxKind.MyBaseKeyword)).Any Then
targetType = containingSymbol.BaseType
Return True
ElseIf TypeOf eventExpression Is IdentifierNameSyntax Then
targetType = containingSymbol
Return True
ElseIf TypeOf eventExpression Is MemberAccessExpressionSyntax Then
If eventType IsNot Nothing Then
targetType = eventType
Return True
End If
End If
Return False
End Function
Private Shared Function IsCandidate(node As SyntaxNode) As Boolean
Return TypeOf node Is HandlesClauseItemSyntax OrElse TypeOf node Is QualifiedNameSyntax OrElse TypeOf node Is AddRemoveHandlerStatementSyntax
End Function
Private Shared Async Function GenerateEventFromImplementsAsync(document As Document, node As QualifiedNameSyntax, cancellationToken As CancellationToken) As Task(Of CodeAction)
If node.Right.IsMissing Then
Return Nothing
End If
' We must be trying to implement an event
If Not node.IsParentKind(SyntaxKind.ImplementsClause) OrElse Not node.Parent.IsParentKind(SyntaxKind.EventStatement) Then
Return Nothing
End If
' Does this name already bind?
Dim semanticModel = Await document.GetSemanticModelAsync(cancellationToken).ConfigureAwait(False)
Dim nameToGenerate = semanticModel.GetSymbolInfo(node, cancellationToken).Symbol
If nameToGenerate IsNot Nothing Then
Return Nothing
End If
Dim targetType = TryCast(SymbolFinder.FindSourceDefinition(semanticModel.GetSymbolInfo(node.Left, cancellationToken).Symbol, document.Project.Solution, cancellationToken), INamedTypeSymbol)
If targetType Is Nothing OrElse (targetType.TypeKind <> TypeKind.Interface AndAlso targetType.TypeKind <> TypeKind.Class) Then
Return Nothing
End If
Dim boundEvent = TryCast(semanticModel.GetDeclaredSymbol(node.Parent.Parent, cancellationToken), IEventSymbol)
If boundEvent Is Nothing Then
Return Nothing
End If
Dim codeGenService = document.Project.Solution.Services.GetLanguageServices(targetType.Language).GetService(Of ICodeGenerationService)
Dim actualEventName = node.Right.Identifier.ValueText
' If we support parameterized events (C#) and it's an event declaration with a parameter list
' (not a type), we need to generate a delegate type in the C# file.
Dim eventSyntax = node.GetAncestor(Of EventStatementSyntax)()
If eventSyntax.ParameterList IsNot Nothing Then
Dim eventType = TryCast(boundEvent.Type, INamedTypeSymbol)
If eventType Is Nothing Then
Return Nothing
End If
Dim returnType = If(eventType.DelegateInvokeMethod IsNot Nothing,
eventType.DelegateInvokeMethod.ReturnType,
semanticModel.Compilation.GetSpecialType(SpecialType.System_Void))
Dim parameters = If(eventType.DelegateInvokeMethod IsNot Nothing,
eventType.DelegateInvokeMethod.Parameters,
ImmutableArray(Of IParameterSymbol).Empty)
Dim eventHandlerType = CodeGenerationSymbolFactory.CreateDelegateTypeSymbol(
eventType.GetAttributes(), eventType.DeclaredAccessibility,
modifiers:=Nothing, returnType:=returnType, refKind:=RefKind.None,
name:=actualEventName + "EventHandler",
typeParameters:=eventType.TypeParameters, parameters:=parameters)
Dim generatedEvent = CodeGenerationSymbolFactory.CreateEventSymbol(
boundEvent.GetAttributes(), boundEvent.DeclaredAccessibility,
modifiers:=Nothing, type:=eventHandlerType, explicitInterfaceImplementations:=Nothing,
name:=actualEventName)
' Point the delegate back at the event symbol. This way the generators know to generate parameters
' instead of an 'As' clause.
eventHandlerType.AssociatedSymbol = generatedEvent
Return New GenerateEventCodeAction(document.Project.Solution, targetType, generatedEvent, codeGenService)
Else
' Event with no parameters.
Dim generatedMember = CodeGenerationSymbolFactory.CreateEventSymbol(boundEvent, name:=actualEventName)
Return New GenerateEventCodeAction(document.Project.Solution, targetType, generatedMember, codeGenService)
End If
End Function
Private Shared Async Function GenerateEventFromHandlesAsync(document As Document, handlesClauseItem As HandlesClauseItemSyntax, cancellationToken As CancellationToken) As Task(Of CodeAction)
If handlesClauseItem.IsMissing OrElse handlesClauseItem.EventContainer.IsMissing OrElse handlesClauseItem.EventMember.IsMissing Then
Return Nothing
End If
Dim semanticModel = Await document.GetSemanticModelAsync(cancellationToken).ConfigureAwait(False)
' Does this handlesClauseItem actually bind?
Dim symbol = semanticModel.GetSymbolInfo(handlesClauseItem, cancellationToken).Symbol
If symbol IsNot Nothing Then
Return Nothing
End If
Dim targetType As INamedTypeSymbol = Nothing
Dim keywordEventContainer = TryCast(handlesClauseItem.EventContainer, KeywordEventContainerSyntax)
If keywordEventContainer IsNot Nothing Then
' Me/MyClass/MyBase
Dim containingSymbol = semanticModel.GetEnclosingNamedType(handlesClauseItem.SpanStart, cancellationToken)
If containingSymbol Is Nothing Then
Return Nothing
End If
If keywordEventContainer.Keyword.IsKind(SyntaxKind.MeKeyword, SyntaxKind.MyClassKeyword) Then
targetType = containingSymbol
ElseIf keywordEventContainer.Keyword.IsKind(SyntaxKind.MyBaseKeyword) Then
targetType = containingSymbol.BaseType
End If
Else
' Withevents property. We'll generate into its type.
Dim withEventsProperty = TryCast(semanticModel.GetSymbolInfo(handlesClauseItem.EventContainer, cancellationToken).Symbol, IPropertySymbol)
If withEventsProperty Is Nothing OrElse Not withEventsProperty.IsWithEvents Then
Return Nothing
End If
targetType = TryCast(SymbolFinder.FindSourceDefinition(withEventsProperty.Type, document.Project.Solution, cancellationToken), INamedTypeSymbol)
End If
targetType = TryCast(SymbolFinder.FindSourceDefinition(targetType, document.Project.Solution, cancellationToken), INamedTypeSymbol)
If targetType Is Nothing OrElse
Not (targetType.TypeKind = TypeKind.Class OrElse targetType.TypeKind = TypeKind.Interface) OrElse
targetType.IsAnonymousType Then
Return Nothing
End If
' Our target type may be from a CSharp file, in which case we should resolve it to our VB compilation.
Dim originalTargetType = targetType
targetType = DirectCast(targetType.GetSymbolKey(cancellationToken).Resolve(semanticModel.Compilation, cancellationToken:=cancellationToken).Symbol, INamedTypeSymbol)
If targetType Is Nothing Then
Return Nothing
End If
If semanticModel.LookupSymbols(handlesClauseItem.SpanStart, container:=targetType, name:=handlesClauseItem.EventMember.Identifier.ValueText).
Any(Function(x) x.MatchesKind(SymbolKind.Event) AndAlso x.Name = handlesClauseItem.EventMember.Identifier.ValueText) Then
Return Nothing
End If
If targetType.GetMembers(handlesClauseItem.EventMember.Identifier.ValueText).Any() Then
Return Nothing
End If
Dim codeGenService = document.Project.Solution.Services.GetLanguageServices(originalTargetType.Language).GetService(Of ICodeGenerationService)
' Let's bind the method declaration so we can get its parameters.
Dim boundMethod = semanticModel.GetDeclaredSymbol(handlesClauseItem.GetAncestor(Of MethodStatementSyntax)(), cancellationToken)
If boundMethod Is Nothing Then
Return Nothing
End If
Dim actualEventName = handlesClauseItem.EventMember.Identifier.ValueText
' We need to generate the delegate, too.
Dim delegateType = CodeGenerationSymbolFactory.CreateDelegateTypeSymbol(
attributes:=Nothing, accessibility:=Accessibility.Public, modifiers:=Nothing,
returnType:=semanticModel.Compilation.GetSpecialType(SpecialType.System_Void),
refKind:=RefKind.None, name:=actualEventName + "Handler",
parameters:=boundMethod.GetParameters())
Dim generatedEvent = CodeGenerationSymbolFactory.CreateEventSymbol(
attributes:=Nothing, accessibility:=Accessibility.Public, modifiers:=Nothing,
explicitInterfaceImplementations:=Nothing,
type:=delegateType, name:=actualEventName)
' Point the delegate back at the event symbol. This way the generators know to generate parameters
' instead of an 'As' clause.
delegateType.AssociatedSymbol = generatedEvent
Return New GenerateEventCodeAction(
document.Project.Solution, originalTargetType, generatedEvent, codeGenService)
End Function
End Class
End Namespace
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