[release/6.0-preview4] Add JSON source generator

src/libraries/System.Text.Json/src/System/Text/Json/Serialization/JsonIgnoreCondition.cs → src/libraries/System.Text.Json/Common/JsonIgnoreCondition.cs

@@ -7,10 +7,15 @@ namespace System.Text.Json.Serialization
     /// When specified on <see cref="JsonSerializerOptions.DefaultIgnoreCondition"/>,
     /// determines when properties and fields across the type graph are ignored.
     /// When specified on <see cref="JsonIgnoreAttribute.Condition"/>, controls whether
-    /// a property is ignored during serialization and deserialization. This option
+    /// a property or field is ignored during serialization and deserialization. This option
     /// overrides the setting on <see cref="JsonSerializerOptions.DefaultIgnoreCondition"/>.
     /// </summary>
-    public enum JsonIgnoreCondition
+#if BUILDING_SOURCE_GENERATOR
+    internal
+#else
+    public
+#endif
+    enum JsonIgnoreCondition
     {
         /// <summary>
         /// Property is never ignored during serialization or deserialization.

src/libraries/System.Text.Json/src/System/Text/Json/Serialization/JsonNumberHandling.cs → src/libraries/System.Text.Json/Common/JsonNumberHandling.cs

@@ -7,23 +7,31 @@ namespace System.Text.Json.Serialization
     /// Determines how <see cref="JsonSerializer"/> handles numbers when serializing and deserializing.
     /// </summary>
     [Flags]
-    public enum JsonNumberHandling
+#if BUILDING_SOURCE_GENERATOR
+    internal
+#else
+    public
+#endif
+     enum JsonNumberHandling
     {
         /// <summary>
         /// Numbers will only be read from <see cref="JsonTokenType.Number"/> tokens and will only be written as JSON numbers (without quotes).
         /// </summary>
         Strict = 0x0,
+
         /// <summary>
         /// Numbers can be read from <see cref="JsonTokenType.String"/> tokens.
         /// Does not prevent numbers from being read from <see cref="JsonTokenType.Number"/> token.
         /// Strings that have escaped characters will be unescaped before reading.
         /// Leading or trailing trivia within the string token, including whitespace, is not allowed.
         /// </summary>
         AllowReadingFromString = 0x1,
+
         /// <summary>
         /// Numbers will be written as JSON strings (with quotes), not as JSON numbers.
         /// </summary>
         WriteAsString = 0x2,
+
         /// <summary>
         /// The "NaN", "Infinity", and "-Infinity" <see cref="JsonTokenType.String"/> tokens can be read as
         /// floating-point constants, and the <see cref="float"/> and <see cref="double"/> values for these

src/libraries/System.Text.Json/System.Text.Json.sln

@@ -27,18 +27,25 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "System.Text.Json", "ref\Sys
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "System.Text.Json", "src\System.Text.Json.csproj", "{1285FF43-F491-4BE0-B92C-37DA689CBD4B}"
 EndProject
-Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "System.Text.Json.Tests", "tests\System.Text.Json.Tests.csproj", "{607D1960-1428-40D5-8AC4-D98E3C9BCF47}"
-EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "tests", "tests", "{3C544454-BD8B-44F4-A174-B61F18957613}"
 EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "ref", "ref", "{EC8CE194-261A-4115-9582-E2DB1A25CAFB}"
 EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "src", "src", "{676B6044-FA47-4B7D-AEC2-FA94DB23A423}"
 EndProject
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "gen", "gen", "{74017ACD-3AC1-4BB5-804B-D57E305FFBD9}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "System.Text.Json.SourceGeneration", "gen\System.Text.Json.SourceGeneration.csproj", "{6485EED4-C313-4551-9865-8ADCED603629}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "System.Text.Json.Tests", "tests\System.Text.Json.Tests\System.Text.Json.Tests.csproj", "{A0178BAA-A1AF-4C69-8E4A-A700A2723DDC}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "System.Text.Json.SourceGeneration.Tests", "tests\System.Text.Json.SourceGeneration.Tests\System.Text.Json.SourceGeneration.Tests.csproj", "{33599A6C-F340-4E1B-9B4D-CB8946C22140}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "System.Text.Json.SourceGeneration.UnitTests", "tests\System.Text.Json.SourceGeneration.UnitTests\System.Text.Json.SourceGeneration.UnitTests.csproj", "{18173CEC-895F-4F62-B7BB-B724457FEDCD}"
+EndProject
 Global
 	GlobalSection(NestedProjects) = preSolution
 		{102945CA-3736-4B2C-8E68-242A0B247F2B} = {3C544454-BD8B-44F4-A174-B61F18957613}
-		{607D1960-1428-40D5-8AC4-D98E3C9BCF47} = {3C544454-BD8B-44F4-A174-B61F18957613}
 		{73D5739C-E382-4E22-A7D3-B82705C58C74} = {EC8CE194-261A-4115-9582-E2DB1A25CAFB}
 		{25C42754-B384-4842-8FA7-75D7A79ADF0D} = {EC8CE194-261A-4115-9582-E2DB1A25CAFB}
 		{4774F56D-16A8-4ABB-8C73-5F57609F1773} = {EC8CE194-261A-4115-9582-E2DB1A25CAFB}
@@ -52,6 +59,10 @@ Global
 		{7909EB27-0D6E-46E6-B9F9-8A1EFD557018} = {676B6044-FA47-4B7D-AEC2-FA94DB23A423}
 		{9BCCDA15-8907-4AE3-8871-2F17775DDE4C} = {676B6044-FA47-4B7D-AEC2-FA94DB23A423}
 		{1285FF43-F491-4BE0-B92C-37DA689CBD4B} = {676B6044-FA47-4B7D-AEC2-FA94DB23A423}
+		{6485EED4-C313-4551-9865-8ADCED603629} = {74017ACD-3AC1-4BB5-804B-D57E305FFBD9}
+		{A0178BAA-A1AF-4C69-8E4A-A700A2723DDC} = {3C544454-BD8B-44F4-A174-B61F18957613}
+		{33599A6C-F340-4E1B-9B4D-CB8946C22140} = {3C544454-BD8B-44F4-A174-B61F18957613}
+		{18173CEC-895F-4F62-B7BB-B724457FEDCD} = {3C544454-BD8B-44F4-A174-B61F18957613}
 	EndGlobalSection
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -114,10 +125,22 @@ Global
 		{1285FF43-F491-4BE0-B92C-37DA689CBD4B}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{1285FF43-F491-4BE0-B92C-37DA689CBD4B}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{1285FF43-F491-4BE0-B92C-37DA689CBD4B}.Release|Any CPU.Build.0 = Release|Any CPU
-		{607D1960-1428-40D5-8AC4-D98E3C9BCF47}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		{607D1960-1428-40D5-8AC4-D98E3C9BCF47}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		{607D1960-1428-40D5-8AC4-D98E3C9BCF47}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		{607D1960-1428-40D5-8AC4-D98E3C9BCF47}.Release|Any CPU.Build.0 = Release|Any CPU
+		{6485EED4-C313-4551-9865-8ADCED603629}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{6485EED4-C313-4551-9865-8ADCED603629}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{6485EED4-C313-4551-9865-8ADCED603629}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{6485EED4-C313-4551-9865-8ADCED603629}.Release|Any CPU.Build.0 = Release|Any CPU
+		{A0178BAA-A1AF-4C69-8E4A-A700A2723DDC}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{A0178BAA-A1AF-4C69-8E4A-A700A2723DDC}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{A0178BAA-A1AF-4C69-8E4A-A700A2723DDC}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{A0178BAA-A1AF-4C69-8E4A-A700A2723DDC}.Release|Any CPU.Build.0 = Release|Any CPU
+		{33599A6C-F340-4E1B-9B4D-CB8946C22140}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{33599A6C-F340-4E1B-9B4D-CB8946C22140}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{33599A6C-F340-4E1B-9B4D-CB8946C22140}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{33599A6C-F340-4E1B-9B4D-CB8946C22140}.Release|Any CPU.Build.0 = Release|Any CPU
+		{18173CEC-895F-4F62-B7BB-B724457FEDCD}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{18173CEC-895F-4F62-B7BB-B724457FEDCD}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{18173CEC-895F-4F62-B7BB-B724457FEDCD}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{18173CEC-895F-4F62-B7BB-B724457FEDCD}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

src/libraries/System.Text.Json/gen/ClassType.cs

@@ -0,0 +1,21 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace System.Text.Json.SourceGeneration
+{
+    internal enum ClassType
+    {
+        TypeUnsupportedBySourceGen = 0,
+        Object = 1,
+        KnownType = 2,
+        TypeWithDesignTimeProvidedCustomConverter = 3,
+        Enumerable = 4,
+        Dictionary = 5,
+        Nullable = 6,
+        Enum = 7,
+    }
+}

src/libraries/System.Text.Json/gen/CollectionType.cs

@@ -0,0 +1,19 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace System.Text.Json.SourceGeneration
+{
+    internal enum CollectionType
+    {
+        NotApplicable = 0,
+        Array = 1,
+        List = 2,
+        IEnumerable = 3,
+        IList = 4,
+        Dictionary = 5
+    }
+}

src/libraries/System.Text.Json/gen/IsExternalInit.cs

@@ -0,0 +1,10 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace System.Runtime.CompilerServices
+{
+    /// <summary>
+    /// Dummy class so C# init-only properties can compile on NetStandard.
+    /// </summary>
+    internal sealed class IsExternalInit { }
+}

src/libraries/System.Text.Json/gen/JsonSerializableSyntaxReceiver.cs

@@ -0,0 +1,22 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Collections.Generic;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+
+namespace System.Text.Json.SourceGeneration
+{
+    internal sealed class JsonSerializableSyntaxReceiver : ISyntaxReceiver
+    {
+        public List<CompilationUnitSyntax> CompilationUnits { get; } = new();
+
+        public void OnVisitSyntaxNode(SyntaxNode syntaxNode)
+        {
+            if (syntaxNode is CompilationUnitSyntax compilationUnit)
+            {
+                CompilationUnits.Add(compilationUnit);
+            }
+        }
+    }
+}

src/libraries/System.Text.Json/gen/JsonSourceGenerator.cs

@@ -0,0 +1,128 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
+using System.Text.Json.SourceGeneration.Reflection;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+
+namespace System.Text.Json.SourceGeneration
+{
+    /// <summary>
+    /// Generates source code to optimize serialization and deserialization with JsonSerializer.
+    /// </summary>
+    [Generator]
+    public sealed class JsonSourceGenerator : ISourceGenerator
+    {
+        private JsonSourceGeneratorHelper? _helper;
+
+        /// <summary>
+        /// Helper for unit tests.
+        /// </summary>
+        public Dictionary<string, Type>? SerializableTypes => _helper.GetSerializableTypes();
+
+        /// <summary>
+        /// Registers a syntax resolver to receive compilation units.
+        /// </summary>
+        /// <param name="context"></param>
+        public void Initialize(GeneratorInitializationContext context)
+        {
+            context.RegisterForSyntaxNotifications(() => new JsonSerializableSyntaxReceiver());
+        }
+
+        /// <summary>
+        /// Generates source code to optimize serialization and deserialization with JsonSerializer.
+        /// </summary>
+        /// <param name="executionContext"></param>
+        public void Execute(GeneratorExecutionContext executionContext)
+        {
+            Compilation compilation = executionContext.Compilation;
+
+            const string JsonSerializableAttributeName = "System.Text.Json.Serialization.JsonSerializableAttribute";
+            INamedTypeSymbol jsonSerializableAttribute = compilation.GetTypeByMetadataName(JsonSerializableAttributeName);
+            if (jsonSerializableAttribute == null)
+            {
+                return;
+            }
+
+            JsonSerializableSyntaxReceiver receiver = (JsonSerializableSyntaxReceiver)executionContext.SyntaxReceiver;
+            MetadataLoadContextInternal metadataLoadContext = new(compilation);
+
+            TypeExtensions.NullableOfTType = metadataLoadContext.Resolve(typeof(Nullable<>));
+
+            JsonSourceGeneratorHelper helper = new(executionContext, metadataLoadContext);
+            _helper = helper;
+
+            // Discover serializable types indicated by JsonSerializableAttribute.
+            foreach (CompilationUnitSyntax compilationUnit in receiver.CompilationUnits)
+            {
+                SemanticModel compilationSemanticModel = executionContext.Compilation.GetSemanticModel(compilationUnit.SyntaxTree);
+
+                foreach (AttributeListSyntax attributeListSyntax in compilationUnit.AttributeLists)
+                {
+                    AttributeSyntax attributeSyntax = attributeListSyntax.Attributes.First();
+                    IMethodSymbol attributeSymbol = compilationSemanticModel.GetSymbolInfo(attributeSyntax).Symbol as IMethodSymbol;
+
+                    if (attributeSymbol == null || !jsonSerializableAttribute.Equals(attributeSymbol.ContainingType, SymbolEqualityComparer.Default))
+                    {
+                        // Not the right attribute.
+                        continue;
+                    }
+
+                    // Get JsonSerializableAttribute arguments.
+                    IEnumerable<SyntaxNode> attributeArguments = attributeSyntax.DescendantNodes().Where(node => node is AttributeArgumentSyntax);
+
+                    ITypeSymbol? typeSymbol = null;
+                    string? typeInfoPropertyName = null;
+
+                    int i = 0;
+                    foreach (AttributeArgumentSyntax node in attributeArguments)
+                    {
+                        if (i == 0)
+                        {
+                            TypeOfExpressionSyntax? typeNode = node.ChildNodes().Single() as TypeOfExpressionSyntax;
+                            if (typeNode != null)
+                            {
+                                ExpressionSyntax typeNameSyntax = (ExpressionSyntax)typeNode.ChildNodes().Single();
+                                typeSymbol = compilationSemanticModel.GetTypeInfo(typeNameSyntax).ConvertedType;
+                            }
+                        }
+                        else if (i == 1)
+                        {
+                            // Obtain the optional TypeInfoPropertyName string property on the attribute, if present.
+                            SyntaxNode? typeInfoPropertyNameNode = node.ChildNodes().ElementAtOrDefault(1);
+                            if (typeInfoPropertyNameNode != null)
+                            {
+                                typeInfoPropertyName = typeInfoPropertyNameNode.GetFirstToken().ValueText;
+                            }
+                        }
+
+                        i++;
+                    }
+
+                    if (typeSymbol == null)
+                    {
+                        continue;
+                    }
+
+
+                    Type type = new TypeWrapper(typeSymbol, metadataLoadContext);
+                    if (type.Namespace == "<global namespace>")
+                    {
+                        // typeof() reference where the type's name isn't fully qualified.
+                        // The compilation is not valid and the user needs to fix their code.
+                        // The compiler will notify the user so we don't have to.
+                        return;
+                    }
+
+                    helper.RegisterRootSerializableType(type, typeInfoPropertyName);
+                }
+            }
+
+            helper.GenerateSerializationMetadata();
+        }
+    }
+}