Add a shared caching infrastructure for PolyType applications. (#68)

.editorconfig

@@ -161,3 +161,9 @@ dotnet_diagnostic.xUnit2005.severity = none
 
 # SA1208: System using directives should be placed before other using directives
 dotnet_diagnostic.SA1208.severity = none
+
+# IDE0021: Use block body for constructor
+dotnet_diagnostic.IDE0021.severity = none
+
+# IDE0032: Use auto property
+dotnet_diagnostic.IDE0032.severity = none

src/PolyType.Examples/CborSerializer/CborSerializer.Builder.cs

@@ -1,23 +1,26 @@
 using PolyType.Abstractions;
 using PolyType.Examples.CborSerializer.Converters;
-using PolyType.Examples.Utilities;
+using PolyType.Utilities;
 
 namespace PolyType.Examples.CborSerializer;
 
 public static partial class CborSerializer
 {
-    private sealed class Builder : ITypeShapeVisitor
+    private sealed class Builder(TypeGenerationContext generationContext) : ITypeShapeVisitor, ITypeShapeFunc
     {
-        private readonly TypeDictionary _cache = new();
+        public CborConverter<T> GetOrAddConverter<T>(ITypeShape<T> typeShape) =>
+            (CborConverter<T>)generationContext.GetOrAdd(typeShape, this)!;
 
-        public CborConverter<T> BuildConverter<T>(ITypeShape<T> typeShape)
+        object? ITypeShapeFunc.Invoke<T>(ITypeShape<T> typeShape, object? shape)
         {
+            // Check if the type has a built-in converter.
             if (s_builtInConverters.TryGetValue(typeof(T), out CborConverter? defaultConverter))
             {
                 return (CborConverter<T>)defaultConverter;
             }
 
-            return _cache.GetOrAdd<CborConverter<T>>(typeShape, this, self => new DelayedCborConverter<T>(self));
+            // Otherwise, build a converter using the visitor.
+            return typeShape.Accept(this);
         }
 
         public object? VisitObject<T>(IObjectTypeShape<T> objectShape, object? state)
@@ -35,7 +38,7 @@ public CborConverter<T> BuildConverter<T>(ITypeShape<T> typeShape)
 
         public object? VisitProperty<TDeclaringType, TPropertyType>(IPropertyShape<TDeclaringType, TPropertyType> property, object? state)
         {
-            CborConverter<TPropertyType> propertyConverter = BuildConverter(property.PropertyType);
+            CborConverter<TPropertyType> propertyConverter = GetOrAddConverter(property.PropertyType);
             return new CborPropertyConverter<TDeclaringType, TPropertyType>(property, propertyConverter);
         }
 
@@ -62,13 +65,13 @@ public CborConverter<T> BuildConverter<T>(ITypeShape<T> typeShape)
 
         public object? VisitConstructorParameter<TArgumentState, TParameterType>(IConstructorParameterShape<TArgumentState, TParameterType> parameter, object? state)
         {
-            CborConverter<TParameterType> paramConverter = BuildConverter(parameter.ParameterType);
+            CborConverter<TParameterType> paramConverter = GetOrAddConverter(parameter.ParameterType);
             return new CborPropertyConverter<TArgumentState, TParameterType>(parameter, paramConverter);
         }
 
         public object? VisitEnumerable<TEnumerable, TElement>(IEnumerableTypeShape<TEnumerable, TElement> enumerableShape, object? state)
         {
-            CborConverter<TElement> elementConverter = BuildConverter(enumerableShape.ElementType);
+            CborConverter<TElement> elementConverter = GetOrAddConverter(enumerableShape.ElementType);
             Func<TEnumerable, IEnumerable<TElement>> getEnumerable = enumerableShape.GetGetEnumerable();
 
             return enumerableShape.ConstructionStrategy switch
@@ -98,8 +101,8 @@ public CborConverter<T> BuildConverter<T>(ITypeShape<T> typeShape)
 
         public object? VisitDictionary<TDictionary, TKey, TValue>(IDictionaryTypeShape<TDictionary, TKey, TValue> dictionaryShape, object? state) where TKey : notnull
         {
-            CborConverter<TKey> keyConverter = BuildConverter(dictionaryShape.KeyType);
-            CborConverter<TValue> valueConverter = BuildConverter(dictionaryShape.ValueType);
+            CborConverter<TKey> keyConverter = GetOrAddConverter(dictionaryShape.KeyType);
+            CborConverter<TValue> valueConverter = GetOrAddConverter(dictionaryShape.ValueType);
             Func<TDictionary, IReadOnlyDictionary<TKey, TValue>> getDictionary = dictionaryShape.GetGetDictionary();
 
             return dictionaryShape.ConstructionStrategy switch
@@ -132,7 +135,7 @@ public CborConverter<T> BuildConverter<T>(ITypeShape<T> typeShape)
 
         public object? VisitNullable<T>(INullableTypeShape<T> nullableShape, object? state) where T : struct
         {
-            CborConverter<T> elementConverter = BuildConverter(nullableShape.ElementType);
+            CborConverter<T> elementConverter = GetOrAddConverter(nullableShape.ElementType);
             return new CborNullableConverter<T>(elementConverter);
         }
 

src/PolyType.Examples/CborSerializer/CborSerializer.cs

@@ -1,6 +1,10 @@
-using System.Diagnostics;
+using PolyType.Abstractions;
+using PolyType.Examples.CborSerializer.Converters;
+using PolyType.Utilities;
+using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 using System.Formats.Cbor;
-using PolyType.Abstractions;
+using System.Text.Json.Serialization;
 
 namespace PolyType.Examples.CborSerializer;
 
@@ -9,14 +13,20 @@ namespace PolyType.Examples.CborSerializer;
 /// </summary>
 public static partial class CborSerializer
 {
+    private static readonly MultiProviderTypeCache s_converterCaches = new()
+    {
+        DelayedValueFactory = new DelayedCborConverterFactory(),
+        ValueBuilderFactory = ctx => new Builder(ctx),
+    };
+
     /// <summary>
     /// Builds an <see cref="CborConverter{T}"/> instance from the specified shape.
     /// </summary>
     /// <typeparam name="T">The type for which to build the converter.</typeparam>
     /// <param name="shape">The shape instance guiding converter construction.</param>
     /// <returns>An <see cref="CborConverter{T}"/> instance.</returns>
     public static CborConverter<T> CreateConverter<T>(ITypeShape<T> shape) =>
-        new Builder().BuildConverter(shape);
+        (CborConverter<T>)s_converterCaches.GetOrAdd(shape)!;
 
     /// <summary>
     /// Builds an <see cref="CborConverter{T}"/> instance from the specified shape provider.
@@ -27,6 +37,16 @@ public static CborConverter<T> CreateConverter<T>(ITypeShape<T> shape) =>
     public static CborConverter<T> CreateConverter<T>(ITypeShapeProvider shapeProvider) =>
         CreateConverter(shapeProvider.Resolve<T>());
 
+    /// <summary>
+    /// Builds a <see cref="JsonConverter"/> instance from the reflection-based shape provider.
+    /// </summary>
+    /// <typeparam name="T">The type for which to build the converter.</typeparam>
+    /// <returns>An <see cref="JsonConverter{T}"/> instance.</returns>
+    [RequiresUnreferencedCode("PolyType reflection provider requires unreferenced code")]
+    [RequiresDynamicCode("PolyType reflection provider requires dynamic code")]
+    public static CborConverter<T> CreateConverterUsingReflection<T>() =>
+        CreateConverter<T>(ReflectionProvider.ReflectionTypeShapeProvider.Default);
+
     /// <summary>
     /// Serializes a value to a CBOR encoding using the provided converter.
     /// </summary>

src/PolyType.Examples/CborSerializer/Converters/DelayedCborConverterFactory.cs

@@ -0,0 +1,19 @@
+using PolyType.Abstractions;
+using PolyType.Utilities;
+using System.Formats.Cbor;
+
+namespace PolyType.Examples.CborSerializer.Converters;
+
+internal sealed class DelayedCborConverterFactory : IDelayedValueFactory
+{
+    public DelayedValue Create<T>(ITypeShape<T> _) => new DelayedValue<CborConverter<T>>(self => new DelayedCborConverter<T>(self));
+
+    private sealed class DelayedCborConverter<T>(DelayedValue<CborConverter<T>> self) : CborConverter<T>
+    {
+        public override T? Read(CborReader reader)
+            => self.Result.Read(reader);
+
+        public override void Write(CborWriter writer, T? value)
+            => self.Result.Write(writer, value);
+    }
+}