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Sergio0694Sergio0694
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Add initial version of incremental TransitiveMembersGenerator
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‎CommunityToolkit.Mvvm.SourceGenerators/ComponentModel/TransitiveMembersGenerator.Incremental.cs

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// Licensed to the .NET Foundation under one or more agreements.
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// The .NET Foundation licenses this file to you under the MIT license.
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// See the LICENSE file in the project root for more information.
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using System.Collections.Generic;
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using System.Collections.Immutable;
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using System.IO;
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using System.Linq;
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using System.Reflection;
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using System.Text;
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using CommunityToolkit.Mvvm.SourceGenerators.Diagnostics;
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using CommunityToolkit.Mvvm.SourceGenerators.Extensions;
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using CommunityToolkit.Mvvm.SourceGenerators.Models;
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using Microsoft.CodeAnalysis;
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using Microsoft.CodeAnalysis.CSharp;
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using Microsoft.CodeAnalysis.CSharp.Syntax;
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using Microsoft.CodeAnalysis.Text;
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namespace CommunityToolkit.Mvvm.SourceGenerators;
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/// <summary>
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/// A source generator for a given attribute type.
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/// </summary>
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/// <typeparam name="TInfo">The type of info gathered from parsed <see cref="AttributeData"/> instances.</typeparam>
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public abstract partial class TransitiveMembersGenerator2<TInfo> : IIncrementalGenerator
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where TInfo : class
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{
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/// <summary>
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/// The fully qualified name of the attribute type to look for.
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/// </summary>
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private readonly string attributeType;
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/// <summary>
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/// An <see cref="IEqualityComparer{T}"/> instance to compare intermediate models.
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/// </summary>
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/// <remarks>
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/// This is needed to cache extracted info on attributes used to annotate target types.
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/// </remarks>
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private readonly IEqualityComparer<TInfo> comparer;
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/// <summary>
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/// The preloaded <see cref="ClassDeclarationSyntax"/> instance with members to generate.
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/// </summary>
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private readonly ClassDeclarationSyntax classDeclaration;
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/// <summary>
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/// Initializes a new instance of the <see cref="TransitiveMembersGenerator"/> class.
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/// </summary>
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/// <param name="attributeType">The fully qualified name of the attribute type to look for.</param>
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/// <param name="comparer">An <see cref="IEqualityComparer{T}"/> instance to compare intermediate models.</param>
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protected TransitiveMembersGenerator2(string attributeType, IEqualityComparer<TInfo> comparer)
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{
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this.attributeType = attributeType;
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this.comparer = comparer;
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string attributeTypeName = attributeType.Split('.').Last();
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string filename = $"CommunityToolkit.Mvvm.SourceGenerators.EmbeddedResources.{attributeTypeName.Replace("Attribute", string.Empty)}.cs";
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using Stream stream = Assembly.GetExecutingAssembly().GetManifestResourceStream(filename);
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using StreamReader reader = new(stream);
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string observableObjectSource = reader.ReadToEnd();
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SyntaxTree syntaxTree = CSharpSyntaxTree.ParseText(observableObjectSource);
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this.classDeclaration = syntaxTree.GetRoot().DescendantNodes().OfType<ClassDeclarationSyntax>().First();
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}
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/// <inheritdoc/>
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public void Initialize(IncrementalGeneratorInitializationContext context)
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{
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// Validate the language version
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IncrementalValueProvider<bool> isGeneratorSupported =
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context.ParseOptionsProvider
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.Select(static (item, _) => item is CSharpParseOptions { LanguageVersion: >= LanguageVersion.CSharp9 });
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// Get all class declarations
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IncrementalValuesProvider<INamedTypeSymbol> typeSymbols =
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context.SyntaxProvider
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.CreateSyntaxProvider(
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static (node, _) => node is ClassDeclarationSyntax { AttributeLists.Count: > 0 },
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static (context, _) => (INamedTypeSymbol)context.SemanticModel.GetDeclaredSymbol(context.Node)!)
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.Combine(isGeneratorSupported)
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.Where(static item => item.Right)
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.Select(static (item, _) => item.Left);
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// Filter the types with the target attribute
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IncrementalValuesProvider<(INamedTypeSymbol Symbol, TInfo Info)> typeSymbolsWithInfo =
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typeSymbols
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.Select((item, _) => (
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Symbol: item,
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Attribute: item.GetAttributes().FirstOrDefault(a => a.AttributeClass?.HasFullyQualifiedName(this.attributeType) == true)))
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.Where(static item => item.Attribute is not null)!
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.Select((item, _) => (item.Symbol, GetInfo(item.Attribute!)));
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// Gather all generation info, and any diagnostics
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IncrementalValuesProvider<Result<(HierarchyInfo Hierarchy, TInfo Info)>> generationInfoWithErrors =
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typeSymbolsWithInfo.Select((item, _) =>
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{
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if (ValidateTargetType(item.Symbol, item.Info, out ImmutableArray<Diagnostic> diagnostics))
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{
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return new Result<(HierarchyInfo, TInfo)>(
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(HierarchyInfo.From(item.Symbol), item.Info),
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ImmutableArray<Diagnostic>.Empty);
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}
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return new Result<(HierarchyInfo Hierarchy, TInfo Info)>(default, diagnostics);
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});
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// Emit the diagnostic, if needed
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context.ReportDiagnostics(generationInfoWithErrors.Select(static (item, _) => item.Errors));
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// Get the filtered sequence to enable caching
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IncrementalValuesProvider<(HierarchyInfo Hierarchy, TInfo Info)> generationInfo =
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generationInfoWithErrors
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.Where(static item => item.Errors.IsEmpty)
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.Select(static (item, _) => (item.Value.Hierarchy, item.Value.Info))
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.WithComparers(HierarchyInfo.Comparer.Default, this.comparer);
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// Generate the required members
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context.RegisterSourceOutput(generationInfo, (context, item) =>
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{
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ImmutableArray<MemberDeclarationSyntax> memberDeclarations = FilterDeclaredMembers(item.Info, this.classDeclaration);
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CompilationUnitSyntax compilationUnit = item.Hierarchy.GetCompilationUnit(memberDeclarations, this.classDeclaration.BaseList);
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context.AddSource(
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hintName: $"{item.Hierarchy.FilenameHint}.cs",
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sourceText: SourceText.From(compilationUnit.ToFullString(), Encoding.UTF8));
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});
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}
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/// <summary>
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/// Gets an info model from a retrieved <see cref="AttributeData"/> instance.
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/// </summary>
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/// <param name="attributeData">The input <see cref="AttributeData"/> to get info from.</param>
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/// <returns>A <typeparamref name="TInfo"/> instance with data extracted from <paramref name="attributeData"/>.</returns>
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protected abstract TInfo GetInfo(AttributeData attributeData);
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/// <summary>
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/// Validates a target type being processed.
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/// </summary>
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/// <param name="typeSymbol">The <see cref="INamedTypeSymbol"/> instance for the target type.</param>
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/// <param name="info">The <typeparamref name="TInfo"/> instance with the current processing info.</param>
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/// <param name="diagnostics">The resulting diagnostics from the processing operation.</param>
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/// <returns>Whether or not the target type is valid and can be processed normally.</returns>
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protected abstract bool ValidateTargetType(INamedTypeSymbol typeSymbol, TInfo info, out ImmutableArray<Diagnostic> diagnostics);
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/// <summary>
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/// Filters the <see cref="MemberDeclarationSyntax"/> nodes to generate from the input parsed tree.
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/// </summary>
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/// <param name="info">The <typeparamref name="TInfo"/> instance with the current processing info.</param>
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/// <param name="classDeclaration">The input <see cref="ClassDeclarationSyntax"/> with the reference trees to copy.</param>
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/// <returns>A sequence of <see cref="MemberDeclarationSyntax"/> nodes to emit in the generated file.</returns>
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protected abstract ImmutableArray<MemberDeclarationSyntax> FilterDeclaredMembers(TInfo info, ClassDeclarationSyntax classDeclaration);
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}

‎CommunityToolkit.Mvvm.SourceGenerators/Models/HierarchyInfo.Syntax.cs

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/// Creates a <see cref="CompilationUnitSyntax"/> instance wrapping the given members.
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/// </summary>
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/// <param name="memberDeclarations">The input <see cref="MemberDeclarationSyntax"/> instances to use.</param>
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/// <param name="baseList">The optional <see cref="BaseListSyntax"/> instance to add to generated types.</param>
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/// <returns>A <see cref="CompilationUnitSyntax"/> object wrapping <paramref name="memberDeclarations"/>.</returns>
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public CompilationUnitSyntax GetCompilationUnit(ImmutableArray<MemberDeclarationSyntax> memberDeclarations)
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public CompilationUnitSyntax GetCompilationUnit(
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ImmutableArray<MemberDeclarationSyntax> memberDeclarations,
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BaseListSyntax? baseList = null)
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{
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// Create the partial type declaration with the given member declarations.
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// This code produces a class declaration as follows:
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.AddModifiers(Token(SyntaxKind.PartialKeyword))
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.AddMembers(memberDeclarations.ToArray());
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// Add the base list, if present
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if (baseList is not null)
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{
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classDeclarationSyntax = classDeclarationSyntax.WithBaseList(baseList);
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}
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TypeDeclarationSyntax typeDeclarationSyntax = classDeclarationSyntax;
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// Add all parent types in ascending order, if any

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