map to readonly interface

src/Mapster.Tests/WhenMappingToInterface.cs

@@ -84,6 +84,26 @@ public void MapToInstanceWithInterface()
  );
  }
 
+ [TestMethod]
+ public void MapToReadOnlyInterface()
+ {
+ var dto = new Dto
+ {
+ Id = 1,
+ Name = "Test",
+ UnmappedSource = "Lorem ipsum"
+ };
+
+ var idto = dto.Adapt<IReadOnlyInterface>();
+
+ idto.ShouldNotBeNull();
+ idto.ShouldSatisfyAllConditions(
+ () => idto.Id.ShouldBe(dto.Id),
+ () => idto.Name.ShouldBe(dto.Name)
+ );
+ }
+
+
  [TestMethod]
  public void MapToComplexInterface()
  {
@@ -195,6 +215,12 @@ private interface INotVisibleInterface
  string Name { get; set; }
  }
 
+ public interface IReadOnlyInterface
+ {
+ int Id { get; }
+ string Name { get; }
+ }
+
  public interface IInterfaceWithMethods
  {
  int Id { get; set; }

src/Mapster/Adapters/ClassAdapter.cs

@@ -61,7 +61,10 @@ protected override Expression CreateInstantiationExpression(Expression source, E
  var ctor = arg.Settings.MapToConstructor as ConstructorInfo;
  if (ctor == null)
  {
- classConverter = arg.DestinationType.GetConstructors()
+ var destType = arg.DestinationType.GetTypeInfo().IsInterface
+ ? DynamicTypeGenerator.GetTypeForInterface(arg.DestinationType)
+ : arg.DestinationType;
+ classConverter = destType.GetConstructors()
  .OrderByDescending(it => it.GetParameters().Length)
  .Select(it => GetConstructorModel(it, true))
  .Select(it => CreateClassConverter(source, it, arg))

src/Mapster/Adapters/RecordTypeAdapter.cs

@@ -1,5 +1,6 @@
 using System.Linq.Expressions;
 using System.Reflection;
+using Mapster.Utils;
 
 namespace Mapster.Adapters
 {
@@ -20,7 +21,10 @@ protected override Expression CreateInstantiationExpression(Expression source, E
  if (arg.GetConstructUsing() != null)
  return base.CreateInstantiationExpression(source, destination, arg);
 
- var ctor = arg.DestinationType.GetConstructors()[0];
+ var destType = arg.DestinationType.GetTypeInfo().IsInterface
+ ? DynamicTypeGenerator.GetTypeForInterface(arg.DestinationType)
+ : arg.DestinationType;
+ var ctor = destType.GetConstructors()[0];
  var classModel = GetConstructorModel(ctor, false);
  var classConverter = CreateClassConverter(source, classModel, arg);
  return CreateInstantiationExpression(source, classConverter, arg);

src/Mapster/Utils/DynamicTypeGenerator.cs

@@ -1,5 +1,7 @@
 using System;
 using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.Linq;
 using System.Reflection;
 using System.Reflection.Emit;
 using System.Threading;
@@ -8,15 +10,15 @@ namespace Mapster.Utils
 {
  internal static class DynamicTypeGenerator
  {
- private const string DynamicAssemblyName = "MapsterGeneratedTypes";
+ private const string DynamicAssemblyName = "Mapster.Dynamic";
 
  private static readonly AssemblyBuilder _assemblyBuilder =
 #if NET40
  AppDomain.CurrentDomain.DefineDynamicAssembly(new AssemblyName(DynamicAssemblyName), AssemblyBuilderAccess.Run);
 #else
  AssemblyBuilder.DefineDynamicAssembly(new AssemblyName(DynamicAssemblyName), AssemblyBuilderAccess.Run);
 #endif
- private static readonly ModuleBuilder _moduleBuilder = _assemblyBuilder.DefineDynamicModule("Classes");
+ private static readonly ModuleBuilder _moduleBuilder = _assemblyBuilder.DefineDynamicModule("Mapster.Dynamic");
  private static readonly ConcurrentDictionary<Type, Type> _generated = new ConcurrentDictionary<Type, Type>();
  private static int _generatedCounter;
 
@@ -44,9 +46,13 @@ private static Type CreateTypeForInterface(Type interfaceType)
  foreach (Type currentInterface in ReflectionUtils.GetAllInterfaces(interfaceType))
  {
  builder.AddInterfaceImplementation(currentInterface);
+ var args = new List<FieldBuilder>();
  foreach (PropertyInfo prop in currentInterface.GetProperties())
  {
- CreateProperty(currentInterface, builder, prop);
+ FieldBuilder propField = builder.DefineField("_" + NameMatchingStrategy.CamelCase(prop.Name), prop.PropertyType, FieldAttributes.Private);
+ CreateProperty(currentInterface, builder, prop, propField);
+ if (!prop.CanWrite)
+ args.Add(propField);
  }
  foreach (MethodInfo method in currentInterface.GetMethods())
  {
@@ -56,6 +62,23 @@ private static Type CreateTypeForInterface(Type interfaceType)
  CreateMethod(builder, method);
  }
  }
+
+ if (args.Count > 0)
+ {
+ var ctorBuilder = builder.DefineConstructor(MethodAttributes.Public, 
+ CallingConventions.Standard,
+ args.Select(it => it.FieldType).ToArray());
+ var ctorIL = ctorBuilder.GetILGenerator();
+ for (var i = 0; i < args.Count; i++)
+ {
+ var arg = args[i];
+ ctorBuilder.DefineParameter(i + 1, ParameterAttributes.None, arg.Name.Substring(1));
+ ctorIL.Emit(OpCodes.Ldarg_0);
+ ctorIL.Emit(OpCodes.Ldarg_S, i + 1);
+ ctorIL.Emit(OpCodes.Stfld, arg);
+ }
+ ctorIL.Emit(OpCodes.Ret);
+ }
  }
 
 #if NETSTANDARD2_0
@@ -67,14 +90,13 @@ private static Type CreateTypeForInterface(Type interfaceType)
 #endif
  }
 
- private static void CreateProperty(Type interfaceType, TypeBuilder builder, PropertyInfo prop)
+ private static void CreateProperty(Type interfaceType, TypeBuilder builder, PropertyInfo prop, FieldBuilder propField)
  {
  const BindingFlags interfacePropMethodFlags = BindingFlags.Instance | BindingFlags.Public;
  // The property set and get methods require a special set of attributes.
  const MethodAttributes classPropMethodAttrs
  = MethodAttributes.Public | MethodAttributes.Virtual | MethodAttributes.SpecialName | MethodAttributes.HideBySig;
 
- FieldBuilder propField = builder.DefineField("_" + prop.Name, prop.PropertyType, FieldAttributes.Private);
  PropertyBuilder propBuilder = builder.DefineProperty(prop.Name, PropertyAttributes.None, prop.PropertyType, null);
 
  if (prop.CanRead)

src/Mapster/Utils/ReflectionUtils.cs

@@ -227,6 +227,10 @@ public static bool IsRecordType(this Type type)
  if (props.Any(p => p.SetterModifier == AccessModifier.Public))
  return false;
 
+ //interface, ctor will automatically created
+ if (type.GetTypeInfo().IsInterface)
+ return true;
+
  //1 non-empty constructor
  var ctors = type.GetConstructors().Where(ctor => ctor.GetParameters().Length > 0).ToList();
  if (ctors.Count != 1)