{

private static readonly MemberMapImpl<Field> fieldMap = new MemberMapImpl<Field>();

private static readonly MemberMapImpl<Method> methodMap = new MemberMapImpl<Method>();

private static readonly MemberMapImpl<Property> propertyMap = new MemberMapImpl<Property>();

public static FieldInfo GetField(string name)

{

return fieldMap.GetMember(name);

}

public static FieldInfo[] GetFields(string[] names)

{

// ReSharper disable once CoVariantArrayConversion

return fieldMap.GetMembers(names);

}

public static MethodInfo GetMethod(string name)

{

return methodMap.GetMember(name);

}

public static MethodInfo[] GetMethods(string[] names)

{

// ReSharper disable once CoVariantArrayConversion

return methodMap.GetMembers(names);

}

public static PropertyInfo GetProperty(string name)

{

return propertyMap.GetMember(name);

}

public static PropertyInfo[] GetProperties(string[] names)

{

// ReSharper disable once CoVariantArrayConversion

return propertyMap.GetMembers(names);

}

// ReSharper disable ClassNeverInstantiated.Local

#region Nested type: Field

private sealed class Field : FieldInfo

{

public Field(string name)

{

Name = name;

}

#region FieldInfo overrides

public override FieldAttributes Attributes => FieldAttributes.Public;

// This occurs during VB-based dynamic script item invocation. It was not

// observed before script items gained an IReflect/IExpando implementation that

// exposes script item properties as fields. Apparently VB's dynamic invocation

// support not only recognizes IReflect/IExpando but actually favors it over

// DynamicObject.

public override RuntimeFieldHandle FieldHandle => throw new NotImplementedException();

public override Type FieldType => typeof(object);

// This occurs during VB-based dynamic script item invocation. It was not

// observed before script items gained an IReflect/IExpando implementation that

// exposes script item properties as fields. Apparently VB's dynamic invocation

// support not only recognizes IReflect/IExpando but actually favors it over

// DynamicObject.

public override Type DeclaringType => typeof(object);

// This occurs during VB-based dynamic script item invocation. It was not

// observed before script items gained an IReflect/IExpando implementation that

// exposes script item properties as fields. Apparently VB's dynamic invocation

// support not only recognizes IReflect/IExpando but actually favors it over

// DynamicObject.

public override string Name { get; }

public override Type ReflectedType => throw new NotImplementedException();

public override object GetValue(object obj)

{

// This occurs during VB-based dynamic script item invocation. It was not observed

// before script items gained an IReflect/IExpando implementation that exposes

// script item properties as fields. Apparently VB's dynamic invocation support not

// only recognizes IReflect/IExpando but actually favors it over DynamicObject.

if (obj is IReflect reflect)

{

return reflect.InvokeMember(Name, BindingFlags.GetField, null, obj, ArrayHelpers.GetEmptyArray<object>(), null, CultureInfo.InvariantCulture, null);

}

throw new InvalidOperationException("Invalid field retrieval");

}

public override void SetValue(object obj, object value, BindingFlags invokeFlags, Binder binder, CultureInfo culture)

{

// This occurs during VB-based dynamic script item invocation. It was not observed

// before script items gained an IReflect/IExpando implementation that exposes

// script item properties as fields. Apparently VB's dynamic invocation support not

// only recognizes IReflect/IExpando but actually favors it over DynamicObject.

if (obj is IReflect reflect)

{

reflect.InvokeMember(Name, BindingFlags.SetField, null, obj, new[] { value }, null, culture, null);

return;

}

throw new InvalidOperationException("Invalid field assignment");

}

public override object[] GetCustomAttributes(Type attributeType, bool inherit)

{

return ArrayHelpers.GetEmptyArray<object>();

}

public override object[] GetCustomAttributes(bool inherit)

{

throw new NotImplementedException();

}

public override bool IsDefined(Type attributeType, bool inherit)

{

throw new NotImplementedException();

}

#endregion

}

#endregion

#region Nested type: Method

private sealed class Method : MethodInfo

{

public Method(string name)

{

Name = name;

}

#region MethodInfo overrides

public override ICustomAttributeProvider ReturnTypeCustomAttributes => throw new NotImplementedException();

public override MethodAttributes Attributes => throw new NotImplementedException();

public override RuntimeMethodHandle MethodHandle => throw new NotImplementedException();

public override Type DeclaringType => throw new NotImplementedException();

public override string Name { get; }

public override Type ReflectedType => throw new NotImplementedException();

public override MethodInfo GetBaseDefinition()

{

throw new NotImplementedException();

}

public override MethodImplAttributes GetMethodImplementationFlags()

{

throw new NotImplementedException();

}

public override ParameterInfo[] GetParameters()

{

return ArrayHelpers.GetEmptyArray<ParameterInfo>();

}

public override object Invoke(object obj, BindingFlags invokeFlags, Binder binder, object[] args, CultureInfo culture)

{

throw new NotImplementedException();

}

public override object[] GetCustomAttributes(Type attributeType, bool inherit)

{

return ArrayHelpers.GetEmptyArray<object>();

}

public override object[] GetCustomAttributes(bool inherit)

{

throw new NotImplementedException();

}

public override bool IsDefined(Type attributeType, bool inherit)

{

throw new NotImplementedException();

}

#endregion

}

#endregion

#region Nested type: Property

private sealed class Property : PropertyInfo

{

public Property(string name)

{

Name = name;

}

#region PropertyInfo overrides

public override PropertyAttributes Attributes => throw new NotImplementedException();

public override bool CanRead => throw new NotImplementedException();

public override bool CanWrite => throw new NotImplementedException();

public override Type PropertyType => throw new NotImplementedException();

public override Type DeclaringType => throw new NotImplementedException();

public override string Name { get; }

public override Type ReflectedType => throw new NotImplementedException();

public override MethodInfo[] GetAccessors(bool nonPublic)

{

throw new NotImplementedException();

}

public override MethodInfo GetGetMethod(bool nonPublic)

{

throw new NotImplementedException();

}

public override ParameterInfo[] GetIndexParameters()

{

return ArrayHelpers.GetEmptyArray<ParameterInfo>();

}

public override MethodInfo GetSetMethod(bool nonPublic)

{

throw new NotImplementedException();

}

public override object GetValue(object obj, BindingFlags invokeFlags, Binder binder, object[] index, CultureInfo culture)

{

throw new NotImplementedException();

}

public override void SetValue(object obj, object value, BindingFlags invokeFlags, Binder binder, object[] index, CultureInfo culture)

{

throw new NotImplementedException();

}

public override object[] GetCustomAttributes(Type attributeType, bool inherit)

{

return ArrayHelpers.GetEmptyArray<object>();

}

public override object[] GetCustomAttributes(bool inherit)

{

throw new NotImplementedException();

}

public override bool IsDefined(Type attributeType, bool inherit)

{

throw new NotImplementedException();

}

#endregion

}

#endregion

// ReSharper restore ClassNeverInstantiated.Local

#region Nested type: MemberMapBase

private class MemberMapBase

{

protected const int CompactionThreshold = 1024 * 1024;

protected static readonly TimeSpan CompactionInterval = TimeSpan.FromMinutes(5);

}

#endregion

#region Nested type: MemberMapImpl<T>

private sealed class MemberMapImpl<T> : MemberMapBase where T : MemberInfo

{

private readonly Dictionary<string, WeakReference> map = new Dictionary<string, WeakReference>();

private DateTime lastCompactionTime = DateTime.MinValue;

public T GetMember(string name)

{

lock (map)

{

var result = GetMemberInternal(name);

CompactIfNecessary();

return result;

}

}

public T[] GetMembers(string[] names)

{

lock (map)

{

var result = names.Select(GetMemberInternal).ToArray();

CompactIfNecessary();

return result;

}

}

private T GetMemberInternal(string name)

{

T member;

if (map.TryGetValue(name, out var weakRef))

{

member = weakRef.Target as T;

if (member == null)

{

member = (T)typeof(T).CreateInstance(name);

weakRef.Target = member;

}

}

else

{

member = (T)typeof(T).CreateInstance(name);

map.Add(name, new WeakReference(member));

}

return member;

}

private void CompactIfNecessary()

{

if (map.Count >= CompactionThreshold)

{

var now = DateTime.UtcNow;

if ((lastCompactionTime + CompactionInterval) <= now)

{

map.Where(pair => !pair.Value.IsAlive).ToList().ForEach(pair => map.Remove(pair.Key));

lastCompactionTime = now;

}

}

}

}

#endregion