Entity Cloner

Matthieu MEZIL — Sat, 31 May 2008 21:29:00 GMT
I do an EntityCloner which can Clone an entity single or all the graph from one entity.
To clone an entity, I use reflection but the problem of Reflection is it’s far. The way to Clone a product is always the same. So I generate a Delegate on the fly during first call and I always use it.
For this, I use ILGenerator.Emit and ExpressionTree.
With Clone method, you can easy use ApplyPropertyChanges.
Next step is to do an ApplyPropertyChangesOnGraph.
public static class EntityObjectExtension
{
    public static T Clone<T>(this T entityObject) where T : EntityObject, new()
    {
        return EntityCloner<T>.Clone(entityObject);
    }
    public static T CloneWithGraph<T>(this T entityObject) where T : EntityObject, new()
    {
        return EntityCloner<T>.CloneWithGraph(entityObject);
    }
}
 
public static class EntityCloner<T>
    where T : EntityObject, new()
{
    private static Func<T, T> _cloneDelegate;
    private static Func<T, List<EntityObject>, T> _cloneWithGraphDelegate;
    private static Func<PropertyInfo, bool> _clonePropertyDelegateStep1;
    private static Func<PropertyInfo, bool> _clonePropertyDelegateStep2;
 
    private static Func<T, T> CloneDelegate
    {
        get
        {
            if (_cloneDelegate == null)
            {
                var generatedMethod = GenerateCloneMethod(ClonePropertyDelegateStep1, null).CreateDelegate(typeof(Func<T, List<EntityObject>, Func<EntityObject, List<EntityObject>, EntityObject>, T>)) as Func<T, List<EntityObject>, Func<EntityObject, List<EntityObject>, EntityObject>, T>;
                _cloneDelegate = entity => generatedMethod(entity, new List<EntityObject>(), Cloner.CloneEntity);
            }
            return _cloneDelegate;
        }
    }
    private static Func<T, List<EntityObject>, T> CloneWithGraphDelegate
    {
        get
        {
            if (_cloneWithGraphDelegate == null)
            {
                var generatedMethod = GenerateCloneMethod(ClonePropertyDelegateStep1, ClonePropertyDelegateStep2).CreateDelegate(typeof(Func<T, List<EntityObject>, Func<EntityObject, List<EntityObject>, EntityObject>, T>)) as Func<T, List<EntityObject>, Func<EntityObject, List<EntityObject>, EntityObject>, T>;
                _cloneWithGraphDelegate = (entity, entitiesAlreadyCloned) => generatedMethod(entity, entitiesAlreadyCloned, Cloner.CloneEntity);
            }
            return _cloneWithGraphDelegate;
        }
    }
    private static bool AllowClonePropertyStep1(PropertyInfo pi)
    {
        return !(typeof(EntityObject).IsAssignableFrom(pi.PropertyType) ||
            pi.PropertyType.IsGenericType && pi.PropertyType.GetGenericTypeDefinition() == typeof(EntityCollection<>));
    }
    public static Func<PropertyInfo, bool> ClonePropertyDelegateStep1
    {
        get
        {
            if (_clonePropertyDelegateStep1 == null)
                return pi => AllowClonePropertyStep1(pi);
            return _clonePropertyDelegateStep1;
        }
        set
        {
            if (_clonePropertyDelegateStep1 != value)
            {
                _clonePropertyDelegateStep1 = value;
                _cloneDelegate = null;
            }
        }
    }
    public static Func<PropertyInfo, bool> ClonePropertyDelegateStep2
    {
        get
        {
            if (_clonePropertyDelegateStep2 == null)
                return pi => !AllowClonePropertyStep1(pi);
            return _clonePropertyDelegateStep2;
        }
        set
        {
            if (_clonePropertyDelegateStep2 != value)
            {
                _clonePropertyDelegateStep2 = value;
                _cloneDelegate = null;
            }
        }
    }
 
    private static DynamicMethod GenerateCloneMethod(Func<PropertyInfo, bool> step1, Func<PropertyInfo, bool> step2)
    {
        var dynamicMethod = new DynamicMethod("Clone", typeof(T), new Type[] { typeof(T), typeof(List<EntityObject>), typeof(Func<EntityObject, List<EntityObject>, EntityObject>) });
        var cloneIlGenerator = dynamicMethod.GetILGenerator();
        cloneIlGenerator.Emit(OpCodes.Ldarg_0);
        var argNotNullLabel = cloneIlGenerator.DefineLabel();
        cloneIlGenerator.Emit(OpCodes.Brtrue_S, argNotNullLabel);
        cloneIlGenerator.Emit(OpCodes.Ldnull);
        cloneIlGenerator.Emit(OpCodes.Ret);
        cloneIlGenerator.MarkLabel(argNotNullLabel);
        CopyObject(step1, step2, cloneIlGenerator, typeof(T), () => cloneIlGenerator.Emit(OpCodes.Ldarg_0), () => cloneIlGenerator.Emit(OpCodes.Ldarg_1), () => cloneIlGenerator.Emit(OpCodes.Ldarg_2));
        cloneIlGenerator.Emit(OpCodes.Ret);
        return dynamicMethod;
    }
 
    private static void CopyObject(Func<PropertyInfo, bool> step1, Func<PropertyInfo, bool> step2, ILGenerator cloneIlGenerator, Type typeT, Action getSource, Action getEntitiesList, Action getCloneLinkedEntities)
    {
        EntityAlreadyCloned(cloneIlGenerator, getEntitiesList, getSource);
        cloneIlGenerator.Emit(OpCodes.Castclass, typeT);
        var value = cloneIlGenerator.DeclareLocal(typeT);
        cloneIlGenerator.Emit(OpCodes.Stloc_S, value);
        cloneIlGenerator.Emit(OpCodes.Ldloc_S, value);
        var endExistingConditionMethodLabel = cloneIlGenerator.DefineLabel();
        cloneIlGenerator.Emit(OpCodes.Brtrue, endExistingConditionMethodLabel);
        cloneIlGenerator.Emit(OpCodes.Newobj, typeT.GetConstructor(new Type[0]));
        cloneIlGenerator.Emit(OpCodes.Stloc_S, value);
        CopyProps(step1, step2, cloneIlGenerator, value, typeT, getSource, getEntitiesList, getCloneLinkedEntities);
        cloneIlGenerator.MarkLabel(endExistingConditionMethodLabel);
        cloneIlGenerator.Emit(OpCodes.Ldloc, value);
    }
 
    private static void CopyProps(Func<PropertyInfo, bool> step1, Func<PropertyInfo, bool> step2, ILGenerator cloneIlGenerator, LocalBuilder value, Type typeT, Action getSource, Action getEntitiesList, Action getCloneLinkedEntities)
    {
        foreach (var prop in typeT.GetProperties().Where(p => p.CanRead && p.CanWrite && step1 != null && step1(p)))
            ClonePerStep(step1, step2, cloneIlGenerator, value, typeT, getSource, getEntitiesList, getCloneLinkedEntities, prop);
        getEntitiesList();
        cloneIlGenerator.Emit(OpCodes.Ldloc, value);
        cloneIlGenerator.Emit(OpCodes.Callvirt, typeof(List<EntityObject>).GetMethod("Add"));
        foreach (var prop in typeT.GetProperties().Where(p => p.CanRead && p.CanWrite && step2 != null && step2(p)))
            ClonePerStep(step1, step2, cloneIlGenerator, value, typeT, getSource, getEntitiesList, getCloneLinkedEntities, prop);
    }
 
    private static void ClonePerStep(Func<PropertyInfo, bool> step1, Func<PropertyInfo, bool> step2, ILGenerator cloneIlGenerator, LocalBuilder value, Type typeT, Action getSource, Action getEntitiesList, Action getCloneLinkedEntities, PropertyInfo prop)
    {
        if (typeof(ComplexObject).IsAssignableFrom(prop.PropertyType))
        {
            ConstructorInfo complexObjectCtor = prop.PropertyType.GetConstructor(new Type[0]);
            if (complexObjectCtor != null)
            {
                cloneIlGenerator.Emit(OpCodes.Ldloc, value);
                var sourceComplexTypeProp = cloneIlGenerator.DeclareLocal(prop.PropertyType);
                var valueComplexTypeProp = cloneIlGenerator.DeclareLocal(prop.PropertyType);
                getSource();
                cloneIlGenerator.Emit(OpCodes.Callvirt, typeT.GetMethod("get_" + prop.Name));
                cloneIlGenerator.Emit(OpCodes.Stloc_S, sourceComplexTypeProp);
                cloneIlGenerator.Emit(OpCodes.Newobj, complexObjectCtor);
                cloneIlGenerator.Emit(OpCodes.Stloc_S, valueComplexTypeProp);
                cloneIlGenerator.Emit(OpCodes.Ldloc_S, valueComplexTypeProp);
                cloneIlGenerator.Emit(OpCodes.Callvirt, typeT.GetMethod("set_" + prop.Name));
                CopyProps(step1, step2, cloneIlGenerator, valueComplexTypeProp, prop.PropertyType, () => cloneIlGenerator.Emit(OpCodes.Ldloc, sourceComplexTypeProp), getEntitiesList, getCloneLinkedEntities);
            }
        }
        else if (prop.PropertyType.IsGenericType && prop.PropertyType.GetGenericTypeDefinition() == typeof(EntityReference<>))
            CopyEntityReference(cloneIlGenerator, () => cloneIlGenerator.Emit(OpCodes.Ldloc, value), typeT, getSource, prop, false);
        else if (typeof(EntityObject).IsAssignableFrom(prop.PropertyType))
        {
            if (prop.PropertyType.GetConstructor(new Type[0]) != null)
            {
                var entityObjectProp = cloneIlGenerator.DeclareLocal(prop.PropertyType);
                getSource();
                cloneIlGenerator.Emit(OpCodes.Callvirt, typeT.GetMethod("get_" + prop.Name));
                cloneIlGenerator.Emit(OpCodes.Stloc_S, entityObjectProp);
                cloneIlGenerator.Emit(OpCodes.Ldloc_S, entityObjectProp);
                var entityObjectNullLabel = cloneIlGenerator.DefineLabel();
                cloneIlGenerator.Emit(OpCodes.Brfalse_S, entityObjectNullLabel);
                cloneIlGenerator.Emit(OpCodes.Ldloc, value);
                getCloneLinkedEntities();
                cloneIlGenerator.Emit(OpCodes.Ldloc_S, entityObjectProp);
                getEntitiesList();
                cloneIlGenerator.Emit(OpCodes.Callvirt, typeof(Func<EntityObject, List<EntityObject>, EntityObject>).GetMethod("Invoke"));
                cloneIlGenerator.Emit(OpCodes.Castclass, prop.PropertyType);
                cloneIlGenerator.Emit(OpCodes.Callvirt, typeT.GetMethod("set_" + prop.Name));
                cloneIlGenerator.MarkLabel(entityObjectNullLabel);
            }
        }
        else if (prop.PropertyType.IsGenericType && prop.PropertyType.GetGenericTypeDefinition() == typeof(EntityCollection<>))
        {
            var entityCollectionSourceProp = cloneIlGenerator.DeclareLocal(prop.PropertyType);
            getSource();
            cloneIlGenerator.Emit(OpCodes.Callvirt, typeT.GetMethod("get_" + prop.Name));
            cloneIlGenerator.Emit(OpCodes.Stloc_S, entityCollectionSourceProp);
            cloneIlGenerator.Emit(OpCodes.Ldloc_S, entityCollectionSourceProp);
            var entityCollectionNullLabel = cloneIlGenerator.DefineLabel();
            cloneIlGenerator.Emit(OpCodes.Brfalse_S, entityCollectionNullLabel);
            cloneIlGenerator.Emit(OpCodes.Ldloc, value);
            var entityCollectionValueProp = cloneIlGenerator.DeclareLocal(prop.PropertyType);
            cloneIlGenerator.Emit(OpCodes.Newobj, prop.PropertyType.GetConstructor(new Type[0]));
            Type subEntityType = prop.PropertyType.GetGenericArguments()[0];
            if (subEntityType.GetConstructor(new Type[0]) != null)
            {
                cloneIlGenerator.Emit(OpCodes.Stloc_S, entityCollectionValueProp);
                var entityCollectionSourceEnumerator = cloneIlGenerator.DeclareLocal(typeof(IEnumerator<>).MakeGenericType(subEntityType));
                cloneIlGenerator.Emit(OpCodes.Ldloc_S, entityCollectionSourceProp);
                cloneIlGenerator.Emit(OpCodes.Callvirt, prop.PropertyType.GetMethod("GetEnumerator"));
                cloneIlGenerator.Emit(OpCodes.Stloc_S, entityCollectionSourceEnumerator);
                var startAddEntityCollectionLabel = cloneIlGenerator.DefineLabel();
                var endAddEntityCollectionLabel = cloneIlGenerator.DefineLabel();
                cloneIlGenerator.MarkLabel(startAddEntityCollectionLabel);
                cloneIlGenerator.Emit(OpCodes.Ldloc_S, entityCollectionSourceEnumerator);
                cloneIlGenerator.Emit(OpCodes.Callvirt, typeof(IEnumerator).GetMethod("MoveNext"));
                cloneIlGenerator.Emit(OpCodes.Brfalse_S, endAddEntityCollectionLabel);
                var subEntityObject = cloneIlGenerator.DeclareLocal(subEntityType);
                cloneIlGenerator.Emit(OpCodes.Ldloc_S, entityCollectionSourceEnumerator);
                cloneIlGenerator.Emit(OpCodes.Callvirt, typeof(IEnumerator<>).MakeGenericType(subEntityType).GetMethod("get_Current"));
                cloneIlGenerator.Emit(OpCodes.Stloc_S, subEntityObject);
                cloneIlGenerator.Emit(OpCodes.Ldloc_S, entityCollectionValueProp);
                getCloneLinkedEntities();
                cloneIlGenerator.Emit(OpCodes.Ldloc_S, subEntityObject);
                getEntitiesList();
                cloneIlGenerator.Emit(OpCodes.Callvirt, typeof(Func<EntityObject, List<EntityObject>, EntityObject>).GetMethod("Invoke"));
                cloneIlGenerator.Emit(OpCodes.Castclass, subEntityType);
                cloneIlGenerator.Emit(OpCodes.Callvirt, prop.PropertyType.GetMethod("Add", new Type[] { subEntityType }));
                cloneIlGenerator.Emit(OpCodes.Br_S, startAddEntityCollectionLabel);
                cloneIlGenerator.MarkLabel(endAddEntityCollectionLabel);
                cloneIlGenerator.Emit(OpCodes.Ldloc_S, entityCollectionValueProp);
            }
            cloneIlGenerator.Emit(OpCodes.Callvirt, typeT.GetMethod("set_" + prop.Name));
            cloneIlGenerator.MarkLabel(entityCollectionNullLabel);
        }
        else
        {
            cloneIlGenerator.Emit(OpCodes.Ldloc, value);
            getSource();
            cloneIlGenerator.Emit(OpCodes.Callvirt, typeT.GetMethod("get_" + prop.Name));
            cloneIlGenerator.Emit(OpCodes.Callvirt, typeT.GetMethod("set_" + prop.Name));
        }
    }
 
    internal static void CopyEntityReference(ILGenerator cloneIlGenerator, Action loadNewObject, Type typeT, Action getSource, PropertyInfo prop, bool copyNull)
    {
        var sourceEntityReferenceEntityKeyProp = cloneIlGenerator.DeclareLocal(typeof(EntityKey));
        var sourceEntityReferenceEntityKeyMemberProp = cloneIlGenerator.DeclareLocal(typeof(EntityKeyMember));
        var sourceEntityReferenceEntityKeysMemberProp = cloneIlGenerator.DeclareLocal(typeof(EntityKeyMember[]));
        var sourceEntityReferenceEntityKeysMemberLength = cloneIlGenerator.DeclareLocal(typeof(int));
        var valueEntityReferenceProp = cloneIlGenerator.DeclareLocal(prop.PropertyType);
        var valueEntityReferenceEntityKeyProp = cloneIlGenerator.DeclareLocal(typeof(EntityKey));
        var valueEntityReferenceEntityKeysMemberProp = cloneIlGenerator.DeclareLocal(typeof(EntityKeyMember[]));
        var loopIndex = cloneIlGenerator.DeclareLocal(typeof(int));
        loadNewObject();
        cloneIlGenerator.Emit(OpCodes.Newobj, prop.PropertyType.GetConstructor(new Type[0]));
        cloneIlGenerator.Emit(OpCodes.Stloc_S, valueEntityReferenceProp);
        cloneIlGenerator.Emit(OpCodes.Ldloc_S, valueEntityReferenceProp);
        cloneIlGenerator.Emit(OpCodes.Callvirt, typeT.GetMethod("set_" + prop.Name));
        getSource();
        cloneIlGenerator.Emit(OpCodes.Callvirt, typeT.GetMethod("get_" + prop.Name));
        cloneIlGenerator.Emit(OpCodes.Callvirt, prop.PropertyType.GetMethod("get_EntityKey"));
        cloneIlGenerator.Emit(OpCodes.Stloc_S, sourceEntityReferenceEntityKeyProp);
        var entityKeyNullLabel = cloneIlGenerator.DefineLabel();
        cloneIlGenerator.Emit(OpCodes.Ldloc_S, sourceEntityReferenceEntityKeyProp);
        cloneIlGenerator.Emit(OpCodes.Brfalse_S, entityKeyNullLabel);
        cloneIlGenerator.Emit(OpCodes.Ldloc_S, valueEntityReferenceProp);
        cloneIlGenerator.Emit(OpCodes.Ldloc_S, sourceEntityReferenceEntityKeyProp);
        cloneIlGenerator.Emit(OpCodes.Callvirt, typeof(EntityKey).GetMethod("get_EntityKeyValues")); // We suppose EntityKeyValues is not null
        cloneIlGenerator.Emit(OpCodes.Stloc_S, sourceEntityReferenceEntityKeysMemberProp);
        cloneIlGenerator.Emit(OpCodes.Ldloc_S, sourceEntityReferenceEntityKeysMemberProp);
        cloneIlGenerator.Emit(OpCodes.Ldlen);
        cloneIlGenerator.Emit(OpCodes.Conv_I4);
        cloneIlGenerator.Emit(OpCodes.Stloc_S, sourceEntityReferenceEntityKeysMemberLength);
        cloneIlGenerator.Emit(OpCodes.Ldloc_S, sourceEntityReferenceEntityKeysMemberLength);
        cloneIlGenerator.Emit(OpCodes.Newarr, typeof(EntityKeyMember));
        cloneIlGenerator.Emit(OpCodes.Stloc_S, valueEntityReferenceEntityKeysMemberProp);
        var noEntityKeyValues = cloneIlGenerator.DefineLabel();
        cloneIlGenerator.Emit(OpCodes.Ldloc_S, sourceEntityReferenceEntityKeysMemberLength);
        cloneIlGenerator.Emit(OpCodes.Brfalse_S, noEntityKeyValues);
        cloneIlGenerator.Emit(OpCodes.Ldc_I4_0);
        cloneIlGenerator.Emit(OpCodes.Stloc_S, loopIndex);
        var startLoopLabel = cloneIlGenerator.DefineLabel();
        cloneIlGenerator.MarkLabel(startLoopLabel);
        cloneIlGenerator.Emit(OpCodes.Ldloc_S, loopIndex);
        cloneIlGenerator.Emit(OpCodes.Ldloc_S, sourceEntityReferenceEntityKeysMemberLength);
        cloneIlGenerator.Emit(OpCodes.Ceq);
        var endOfLoopLabel = cloneIlGenerator.DefineLabel();
        cloneIlGenerator.Emit(OpCodes.Brtrue_S, endOfLoopLabel);
        cloneIlGenerator.Emit(OpCodes.Ldloc_S, sourceEntityReferenceEntityKeysMemberProp);
        cloneIlGenerator.Emit(OpCodes.Ldloc_S, loopIndex);
        cloneIlGenerator.Emit(OpCodes.Ldelem_Ref);
        cloneIlGenerator.Emit(OpCodes.Stloc_S, sourceEntityReferenceEntityKeyMemberProp);
        cloneIlGenerator.Emit(OpCodes.Ldloc_S, valueEntityReferenceEntityKeysMemberProp);
        cloneIlGenerator.Emit(OpCodes.Ldloc_S, loopIndex);
        cloneIlGenerator.Emit(OpCodes.Ldloc_S, sourceEntityReferenceEntityKeyMemberProp);
        cloneIlGenerator.Emit(OpCodes.Callvirt, typeof(EntityKeyMember).GetMethod("get_Key"));
        cloneIlGenerator.Emit(OpCodes.Ldloc_S, sourceEntityReferenceEntityKeyMemberProp);
        cloneIlGenerator.Emit(OpCodes.Callvirt, typeof(EntityKeyMember).GetMethod("get_Value"));
        cloneIlGenerator.Emit(OpCodes.Newobj, typeof(EntityKeyMember).GetConstructor(new Type[] { typeof(string), typeof(object) }));
        cloneIlGenerator.Emit(OpCodes.Stelem_Ref);
        cloneIlGenerator.Emit(OpCodes.Ldloc_S, loopIndex);
        cloneIlGenerator.Emit(OpCodes.Ldc_I4_1);
        cloneIlGenerator.Emit(OpCodes.Add);
        cloneIlGenerator.Emit(OpCodes.Stloc_S, loopIndex);
        cloneIlGenerator.Emit(OpCodes.Br_S, startLoopLabel);
        cloneIlGenerator.MarkLabel(endOfLoopLabel);
        cloneIlGenerator.Emit(OpCodes.Ldloc_S, sourceEntityReferenceEntityKeyProp);
        cloneIlGenerator.Emit(OpCodes.Callvirt, typeof(EntityKey).GetMethod("get_EntityContainerName"));
        cloneIlGenerator.Emit(OpCodes.Ldstr, ".");
        cloneIlGenerator.Emit(OpCodes.Ldloc_S, sourceEntityReferenceEntityKeyProp);
        cloneIlGenerator.Emit(OpCodes.Callvirt, typeof(EntityKey).GetMethod("get_EntitySetName"));
        cloneIlGenerator.Emit(OpCodes.Call, typeof(string).GetMethod("Concat", new Type[] { typeof(string), typeof(string), typeof(string) })); // We suppose EntityContainerName and EntitySetName aren't null
        cloneIlGenerator.Emit(OpCodes.Ldloc_S, valueEntityReferenceEntityKeysMemberProp);
        cloneIlGenerator.Emit(OpCodes.Newobj, typeof(EntityKey).GetConstructor(new Type[] { typeof(string), typeof(IEnumerable<EntityKeyMember>) }));
        var noEntityKeyValuesEnd = cloneIlGenerator.DefineLabel();
        cloneIlGenerator.Emit(OpCodes.Br, noEntityKeyValuesEnd);
        cloneIlGenerator.MarkLabel(noEntityKeyValues);
        cloneIlGenerator.Emit(OpCodes.Newobj, typeof(EntityKey).GetConstructor(new Type[0]));
        cloneIlGenerator.MarkLabel(noEntityKeyValuesEnd);
        cloneIlGenerator.Emit(OpCodes.Callvirt, prop.PropertyType.GetMethod("set_EntityKey"));
        if (copyNull)
        {
            var endCopyReferenceLabel = cloneIlGenerator.DefineLabel();
            cloneIlGenerator.Emit(OpCodes.Br_S, endCopyReferenceLabel);
            cloneIlGenerator.MarkLabel(entityKeyNullLabel);
            cloneIlGenerator.Emit(OpCodes.Ldloc_S, valueEntityReferenceProp);
            cloneIlGenerator.Emit(OpCodes.Ldnull);
            cloneIlGenerator.Emit(OpCodes.Callvirt, typeof(T).GetMethod("set_" + prop.Name));
            cloneIlGenerator.MarkLabel(endCopyReferenceLabel);
        }
        else
            cloneIlGenerator.MarkLabel(entityKeyNullLabel);
    }
 
    private static void EntityAlreadyCloned(ILGenerator cloneIlGenerator, Action getEntitiesList, Action getSource)
    {
        var loopIndex = cloneIlGenerator.DeclareLocal(typeof(int));
        var entitiesListCount = cloneIlGenerator.DeclareLocal(typeof(int));
        cloneIlGenerator.Emit(OpCodes.Ldc_I4_0);
        cloneIlGenerator.Emit(OpCodes.Stloc_S, loopIndex);
        getEntitiesList();
        cloneIlGenerator.Emit(OpCodes.Callvirt, typeof(List<EntityObject>).GetMethod("get_Count"));
        cloneIlGenerator.Emit(OpCodes.Stloc_S, entitiesListCount);
        var startLoopLabel = cloneIlGenerator.DefineLabel();
        cloneIlGenerator.MarkLabel(startLoopLabel);
        cloneIlGenerator.Emit(OpCodes.Ldloc_S, loopIndex);
        cloneIlGenerator.Emit(OpCodes.Ldloc_S, entitiesListCount);
        cloneIlGenerator.Emit(OpCodes.Ceq);
        var endLoopLabel = cloneIlGenerator.DefineLabel();
        cloneIlGenerator.Emit(OpCodes.Brtrue_S, endLoopLabel);
        var endLabel = cloneIlGenerator.DefineLabel();
        getEntitiesList();
        cloneIlGenerator.Emit(OpCodes.Ldloc_S, loopIndex);
        cloneIlGenerator.Emit(OpCodes.Callvirt, typeof(List<EntityObject>).GetMethod("get_Item"));
        var entityAlreadyCloned = cloneIlGenerator.DeclareLocal(typeof(EntityObject));
        cloneIlGenerator.Emit(OpCodes.Stloc_S, entityAlreadyCloned);
        cloneIlGenerator.Emit(OpCodes.Ldloc_S, entityAlreadyCloned);
        cloneIlGenerator.Emit(OpCodes.Callvirt, typeof(EntityObject).GetMethod("get_EntityKey"));
        getSource();
        cloneIlGenerator.Emit(OpCodes.Callvirt, typeof(EntityObject).GetMethod("get_EntityKey"));
        cloneIlGenerator.Emit(OpCodes.Callvirt, typeof(EntityKey).GetMethod("Equals", new Type[] { typeof(EntityKey) }));
        var entityKeysDifferentsLabel = cloneIlGenerator.DefineLabel();
        cloneIlGenerator.Emit(OpCodes.Brfalse_S, entityKeysDifferentsLabel);
        cloneIlGenerator.Emit(OpCodes.Ldloc_S, entityAlreadyCloned);
        cloneIlGenerator.Emit(OpCodes.Br_S, endLabel);
        cloneIlGenerator.MarkLabel(entityKeysDifferentsLabel);
        cloneIlGenerator.Emit(OpCodes.Ldloc_S, loopIndex);
        cloneIlGenerator.Emit(OpCodes.Ldc_I4_1);
        cloneIlGenerator.Emit(OpCodes.Add);
        cloneIlGenerator.Emit(OpCodes.Stloc_S, loopIndex);
        cloneIlGenerator.Emit(OpCodes.Br_S, startLoopLabel);
        cloneIlGenerator.MarkLabel(endLoopLabel);
        cloneIlGenerator.Emit(OpCodes.Ldnull);
        cloneIlGenerator.MarkLabel(endLabel);
    }
 
    public static T Clone(T obj)
    {
        return CloneDelegate(obj);
    }
    public static T CloneWithGraph(T obj)
    {
        return CloneWithGraph(obj, new List<EntityObject>());
    }
    internal static T CloneWithGraph(T obj, List<EntityObject> entitiesAlreadyCloned)
    {
        return CloneWithGraphDelegate(obj, entitiesAlreadyCloned);
    }
}
 
internal class Cloner
{
    private static Dictionary<Type, Delegate> _cached = new Dictionary<Type, Delegate>();
 
    internal static EntityObject CloneEntity(EntityObject entity, List<EntityObject> entitiesAlreadyCloned)
    {
        Type entityType = entity.GetType();
        if (!_cached.ContainsKey(entityType))
        {
            ParameterExpression paramE = Expression.Parameter(typeof(EntityObject), "e");
            ParameterExpression paramL = Expression.Parameter(typeof(List<EntityObject>), "l");
            Expression<Func<EntityObject, List<EntityObject>, EntityObject>> generatedExpression =
                Expression.Lambda<Func<EntityObject, List<EntityObject>, EntityObject>>(
                    Expression.Call(typeof(EntityCloner<>).MakeGenericType(entityType).GetMethod("CloneWithGraph", BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic, null, new Type[] { entityType, typeof(List<EntityObject>) }, null),
                        Expression.Convert(
                            paramE,
                            entityType),
                        paramL),
                    paramE,
                    paramL);
 
            _cached.Add(entityType, generatedExpression.Compile());
        }
        return _cached[entityType].DynamicInvoke(entity, entitiesAlreadyCloned) as EntityObject;
    }
}
Matthieu MEZIL : MSIL

Reflector IL to C# Bug

Entity Cloner

What do you think about private and protected?
