File: GenerateType\AbstractGenerateTypeService.cs
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Project: src\src\Features\Core\Portable\Microsoft.CodeAnalysis.Features.csproj (Microsoft.CodeAnalysis.Features)
// 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.
 
#nullable disable
 
using System;
using System.Collections.Generic;
using System.Collections.Immutable;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.AddImport;
using Microsoft.CodeAnalysis.CodeActions;
using Microsoft.CodeAnalysis.CodeGeneration;
using Microsoft.CodeAnalysis.Internal.Log;
using Microsoft.CodeAnalysis.LanguageService;
using Microsoft.CodeAnalysis.PooledObjects;
using Microsoft.CodeAnalysis.Shared.Extensions;
using Microsoft.CodeAnalysis.Shared.Utilities;
using Microsoft.CodeAnalysis.Utilities;
using Roslyn.Utilities;
 
namespace Microsoft.CodeAnalysis.GenerateType;
 
internal abstract partial class AbstractGenerateTypeService<TService, TSimpleNameSyntax, TObjectCreationExpressionSyntax, TExpressionSyntax, TTypeDeclarationSyntax, TArgumentSyntax> :
    IGenerateTypeService
    where TService : AbstractGenerateTypeService<TService, TSimpleNameSyntax, TObjectCreationExpressionSyntax, TExpressionSyntax, TTypeDeclarationSyntax, TArgumentSyntax>
    where TSimpleNameSyntax : TExpressionSyntax
    where TObjectCreationExpressionSyntax : TExpressionSyntax
    where TExpressionSyntax : SyntaxNode
    where TTypeDeclarationSyntax : SyntaxNode
    where TArgumentSyntax : SyntaxNode
{
    protected abstract bool TryInitializeState(SemanticDocument document, TSimpleNameSyntax simpleName, CancellationToken cancellationToken, out GenerateTypeServiceStateOptions generateTypeServiceStateOptions);
    protected abstract TExpressionSyntax GetLeftSideOfDot(TSimpleNameSyntax simpleName);
    protected abstract bool TryGetArgumentList(TObjectCreationExpressionSyntax objectCreationExpression, out IList<TArgumentSyntax> argumentList);
 
    protected abstract string DefaultFileExtension { get; }
    protected abstract ImmutableArray<ITypeParameterSymbol> GetTypeParameters(State state, SemanticModel semanticModel, CancellationToken cancellationToken);
    protected abstract Accessibility GetAccessibility(State state, SemanticModel semanticModel, bool intoNamespace, CancellationToken cancellationToken);
    protected abstract IList<ParameterName> GenerateParameterNames(SemanticModel semanticModel, IList<TArgumentSyntax> arguments, CancellationToken cancellationToken);
 
    protected abstract INamedTypeSymbol DetermineTypeToGenerateIn(SemanticModel semanticModel, TSimpleNameSyntax simpleName, CancellationToken cancellationToken);
    protected abstract ITypeSymbol DetermineArgumentType(SemanticModel semanticModel, TArgumentSyntax argument, CancellationToken cancellationToken);
 
    protected abstract bool IsInCatchDeclaration(TExpressionSyntax expression);
    protected abstract bool IsArrayElementType(TExpressionSyntax expression);
    protected abstract bool IsInVariableTypeContext(TExpressionSyntax expression);
    protected abstract bool IsInValueTypeConstraintContext(SemanticModel semanticModel, TExpressionSyntax expression, CancellationToken cancellationToken);
    protected abstract bool IsInInterfaceList(TExpressionSyntax expression);
    internal abstract bool TryGetBaseList(TExpressionSyntax expression, out TypeKindOptions returnValue);
    internal abstract bool IsPublicOnlyAccessibility(TExpressionSyntax expression, Project project);
    internal abstract bool IsGenericName(TSimpleNameSyntax simpleName);
    internal abstract bool IsSimpleName(TExpressionSyntax expression);
 
    internal abstract Task<Solution> TryAddUsingsOrImportToDocumentAsync(
        Solution updatedSolution, SyntaxNode modifiedRoot, Document document, TSimpleNameSyntax simpleName, string includeUsingsOrImports, CancellationToken cancellationToken);
 
    protected abstract bool TryGetNameParts(TExpressionSyntax expression, out IList<string> nameParts);
 
    public abstract string GetRootNamespace(CompilationOptions options);
 
    public abstract Task<(INamespaceSymbol, INamespaceOrTypeSymbol, Location)> GetOrGenerateEnclosingNamespaceSymbolAsync(INamedTypeSymbol namedTypeSymbol, string[] containers, Document selectedDocument, SyntaxNode selectedDocumentRoot, CancellationToken cancellationToken);
 
    public async Task<ImmutableArray<CodeAction>> GenerateTypeAsync(
        Document document,
        SyntaxNode node,
        CancellationToken cancellationToken)
    {
        using (Logger.LogBlock(FunctionId.Refactoring_GenerateType, cancellationToken))
        {
            var semanticDocument = await SemanticDocument.CreateAsync(document, cancellationToken).ConfigureAwait(false);
 
            var state = State.Generate((TService)this, semanticDocument, node, cancellationToken);
            if (state != null)
            {
                var actions = GetActions(semanticDocument, node, state, cancellationToken);
                if (actions.Length > 1)
                {
                    // Wrap the generate type actions into a single top level suggestion
                    // so as to not clutter the list.
                    return [CodeAction.Create(
                        string.Format(FeaturesResources.Generate_type_0, state.Name),
                        actions.AsImmutable(),
                        isInlinable: true)];
                }
                else
                {
                    return actions;
                }
            }
 
            return [];
        }
    }
 
    private ImmutableArray<CodeAction> GetActions(
        SemanticDocument document,
        SyntaxNode node,
        State state,
        CancellationToken cancellationToken)
    {
        using var _ = ArrayBuilder<CodeAction>.GetInstance(out var result);
 
        var generateNewTypeInDialog = false;
        if (state.NamespaceToGenerateInOpt != null)
        {
            if (document.Project.Solution.CanApplyChange(ApplyChangesKind.AddDocument))
            {
                generateNewTypeInDialog = true;
                result.Add(new GenerateTypeCodeAction((TService)this, document.Document, state, intoNamespace: true, inNewFile: true));
            }
 
            // If they just are generating "Goo" then we want to offer to generate it into the
            // namespace in the same file.  However, if they are generating "SomeNS.Goo", then we
            // only want to allow them to generate if "SomeNS" is the namespace they are
            // currently in.
            var isSimpleName = state.SimpleName == state.NameOrMemberAccessExpression;
            var generateIntoContaining = IsGeneratingIntoContainingNamespace(document, node, state, cancellationToken);
 
            if ((isSimpleName || generateIntoContaining) &&
                CanGenerateIntoContainingNamespace(document, node, cancellationToken))
            {
                result.Add(new GenerateTypeCodeAction((TService)this, document.Document, state, intoNamespace: true, inNewFile: false));
            }
        }
 
        if (state.TypeToGenerateInOpt != null)
            result.Add(new GenerateTypeCodeAction((TService)this, document.Document, state, intoNamespace: false, inNewFile: false));
 
        if (generateNewTypeInDialog)
            result.Add(new GenerateTypeCodeActionWithOption((TService)this, document.Document, state));
 
        return result.ToImmutableAndClear();
    }
 
    private static bool CanGenerateIntoContainingNamespace(SemanticDocument semanticDocument, SyntaxNode node, CancellationToken cancellationToken)
    {
        var containingNamespace = semanticDocument.SemanticModel.GetEnclosingNamespace(node.SpanStart, cancellationToken);
 
        // Only allow if the containing namespace is one that can be generated
        // into.  
        var declarationService = semanticDocument.Document.GetLanguageService<ISymbolDeclarationService>();
        var decl = declarationService.GetDeclarations(containingNamespace)
                                     .Where(r => r.SyntaxTree == node.SyntaxTree)
                                     .Select(r => r.GetSyntax(cancellationToken))
                                     .FirstOrDefault(node.GetAncestorsOrThis<SyntaxNode>().Contains);
 
        return
            decl != null &&
            semanticDocument.Document.GetLanguageService<ICodeGenerationService>().CanAddTo(decl, semanticDocument.Project.Solution, cancellationToken);
    }
 
    private static bool IsGeneratingIntoContainingNamespace(
        SemanticDocument document,
        SyntaxNode node,
        State state,
        CancellationToken cancellationToken)
    {
        var containingNamespace = document.SemanticModel.GetEnclosingNamespace(node.SpanStart, cancellationToken);
        if (containingNamespace != null)
        {
            var containingNamespaceName = containingNamespace.ToDisplayString();
            return containingNamespaceName.Equals(state.NamespaceToGenerateInOpt);
        }
 
        return false;
    }
 
    protected static string GetTypeName(State state)
    {
        const string AttributeSuffix = "Attribute";
 
        return state.IsAttribute && !state.NameIsVerbatim && !state.Name.EndsWith(AttributeSuffix, StringComparison.Ordinal)
            ? state.Name + AttributeSuffix
            : state.Name;
    }
 
    protected static ImmutableArray<ITypeParameterSymbol> GetTypeParameters(
        State state,
        SemanticModel semanticModel,
        IEnumerable<SyntaxNode> typeArguments,
        CancellationToken cancellationToken)
    {
        var arguments = typeArguments.ToList();
        var arity = arguments.Count;
        using var _ = ArrayBuilder<ITypeParameterSymbol>.GetInstance(out var typeParameters);
 
        // For anything that was a type parameter, just use the name (if we haven't already
        // used it).  Otherwise, synthesize new names for the parameters.
        using var _1 = ArrayBuilder<string>.GetInstance(arity, out var names);
        using var _2 = ArrayBuilder<bool>.GetInstance(arity, out var isFixed);
        for (var i = 0; i < arity; i++)
        {
            var argument = i < arguments.Count ? arguments[i] : null;
            var type = argument == null ? null : semanticModel.GetTypeInfo(argument, cancellationToken).Type;
            if (type is ITypeParameterSymbol typeParameter)
            {
                var name = type.Name;
 
                // If we haven't seen this type parameter already, then we can use this name
                // and 'fix' it so that it doesn't change. Otherwise, use it, but allow it
                // to be changed if it collides with anything else.
                isFixed.Add(!names.Contains(name));
                names.Add(name);
                typeParameters.Add(typeParameter);
            }
            else
            {
                isFixed.Add(false);
                names.Add("T");
                typeParameters.Add(null);
            }
        }
 
        // We can use a type parameter as long as it hasn't been used in an outer type.
        var canUse = state.TypeToGenerateInOpt == null
            ? (Func<string, bool>)null
            : s => state.TypeToGenerateInOpt.GetAllTypeParameters().All(t => t.Name != s);
 
        NameGenerator.EnsureUniquenessInPlace(names, isFixed, canUse);
        for (var i = 0; i < names.Count; i++)
        {
            if (typeParameters[i] == null || typeParameters[i].Name != names[i])
                typeParameters[i] = CodeGenerationSymbolFactory.CreateTypeParameterSymbol(names[i]);
        }
 
        return typeParameters.ToImmutableAndClear();
    }
 
    protected static Accessibility DetermineDefaultAccessibility(
        State state,
        SemanticModel semanticModel,
        bool intoNamespace,
        CancellationToken cancellationToken)
    {
        if (state.IsPublicAccessibilityForTypeGeneration)
        {
            return Accessibility.Public;
        }
 
        // If we're a nested type of the type being generated into, then the new type can be
        // private.  otherwise, it needs to be internal.
        if (!intoNamespace && state.TypeToGenerateInOpt != null)
        {
            var outerTypeSymbol = semanticModel.GetEnclosingNamedType(state.SimpleName.SpanStart, cancellationToken);
 
            if (outerTypeSymbol != null && outerTypeSymbol.IsContainedWithin(state.TypeToGenerateInOpt))
            {
                return Accessibility.Private;
            }
        }
 
        return Accessibility.Internal;
    }
 
    protected IList<ITypeParameterSymbol> GetAvailableTypeParameters(
        State state,
        SemanticModel semanticModel,
        bool intoNamespace,
        CancellationToken cancellationToken)
    {
        var availableInnerTypeParameters = GetTypeParameters(state, semanticModel, cancellationToken);
        var availableOuterTypeParameters = !intoNamespace && state.TypeToGenerateInOpt != null
            ? state.TypeToGenerateInOpt.GetAllTypeParameters()
            : [];
 
        return availableOuterTypeParameters.Concat(availableInnerTypeParameters).ToList();
    }
 
    protected static async Task<bool> IsWithinTheImportingNamespaceAsync(Document document, int triggeringPosition, string includeUsingsOrImports, CancellationToken cancellationToken)
    {
        var semanticModel = await document.GetSemanticModelAsync(cancellationToken).ConfigureAwait(false);
        if (semanticModel != null)
        {
            var namespaceSymbol = semanticModel.GetEnclosingNamespace(triggeringPosition, cancellationToken);
            if (namespaceSymbol != null && namespaceSymbol.ToDisplayString().StartsWith(includeUsingsOrImports, StringComparison.Ordinal))
            {
                return true;
            }
        }
 
        return false;
    }
}