Improve incrementalism by doing less work when not applicable

dotnet · Aug 24, 2021 · bfa08f6 · bfa08f6
1 parent 92da59a
commit bfa08f6
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Showing 2 changed files with 37 additions and 3 deletions.
diff --git a/src/libraries/System.Text.Json/gen/JsonSourceGenerator.Parser.cs b/src/libraries/System.Text.Json/gen/JsonSourceGenerator.Parser.cs
@@ -45,7 +45,7 @@ private sealed class Parser
             private readonly Type? _dictionaryType;
             private readonly Type? _idictionaryOfTKeyTValueType;
             private readonly Type? _ireadonlyDictionaryType;
-            private readonly Type? _isetType; 
+            private readonly Type? _isetType;
             private readonly Type? _stackOfTType;
             private readonly Type? _queueOfTType;
             private readonly Type? _concurrentStackType;
@@ -403,6 +403,37 @@ private static bool TryGetClassDeclarationList(INamedTypeSymbol typeSymbol, [Not
                 return typeGenerationSpec;
             }
 
+            internal static bool IsSyntaxTargetForGeneration(SyntaxNode node) => node is ClassDeclarationSyntax { AttributeLists: { Count: > 0 }, BaseList: { Types : {Count : 0 } } };
+
+            internal static ClassDeclarationSyntax? IsSemanticTargetForGeneration(GeneratorSyntaxContext context)
+            {
+                var classDeclarationSyntax = (ClassDeclarationSyntax)context.Node;
+
+                foreach (AttributeListSyntax attributeListSyntax in classDeclarationSyntax.AttributeLists)
+                {
+                    foreach (var attributeSyntax in attributeListSyntax.Attributes)
+                    {
+                        IMethodSymbol attributeSymbol = context.SemanticModel.GetSymbolInfo(attributeSyntax).Symbol as IMethodSymbol;
+                        if (attributeSymbol == null)
+                        {
+                            continue;
+                        }
+
+                        INamedTypeSymbol attributeContainingTypeSymbol = attributeSymbol.ContainingType;
+                        var fullName = attributeContainingTypeSymbol.ToDisplayString();
+
+                        if (fullName == "System.Text.Json.Serialization.JsonSerializableAttribute"
+                            || fullName == "System.Text.Json.Serialization.JsonSourceGenerationOptionsAttribute")
+                        {
+                            return classDeclarationSyntax;
+                        }
+                    }
+
+                }
+
+                return null;
+            }
+
             private static JsonSourceGenerationMode? GetJsonSourceGenerationModeEnumVal(SyntaxNode propertyValueMode)
             {
                 IEnumerable<string> enumTokens = propertyValueMode

diff --git a/src/libraries/System.Text.Json/gen/JsonSourceGenerator.cs b/src/libraries/System.Text.Json/gen/JsonSourceGenerator.cs
@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+//define LAUNCH_DEBUGGER
 using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Diagnostics;
@@ -23,10 +24,12 @@ public sealed partial class JsonSourceGenerator : IIncrementalGenerator
         private const string IJsonOnSerializedFullName = "System.Text.Json.Serialization.IJsonOnSerialized";
         private const string IJsonOnSerializingFullName = "System.Text.Json.Serialization.IJsonOnSerializing";
 
-
         public void Initialize(IncrementalGeneratorInitializationContext context)
         {
-            var classDeclarations = context.SyntaxProvider.CreateSyntaxProvider((s, _) => s is ClassDeclarationSyntax, (s, _) => (ClassDeclarationSyntax)s.Node);
+
+            var classDeclarations = context.SyntaxProvider
+                .CreateSyntaxProvider((s, _) => Parser.IsSyntaxTargetForGeneration(s), (s, _) => Parser.IsSemanticTargetForGeneration(s))
+                .Where(c => c is object);
 
             var compilationAndClasses = context.CompilationProvider.Combine(classDeclarations.Collect());