#region Copyright notice and license

// Copyright 2015-2016 gRPC authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#endregion

// Content of this file is copied with permission from:
// https://github.com/dotnet/runtime/tree/e2e43f44f1032780fa7c2bb965153c9da615c3d0/src/libraries/System.Private.CoreLib/src/System/Diagnostics/CodeAnalysis
// These types are intented to be added as internalized source to libraries and apps that want to
// use them without requiring a dependency on .NET 5.

namespace System.Diagnostics.CodeAnalysis
{
    /// <summary>
    /// Indicates that certain members on a specified <see cref="Type"/> are accessed dynamically,
    /// for example through <see cref="System.Reflection"/>.
    /// </summary>
    /// <remarks>
    /// This allows tools to understand which members are being accessed during the execution
    /// of a program.
    ///
    /// This attribute is valid on members whose type is <see cref="Type"/> or <see cref="string"/>.
    ///
    /// When this attribute is applied to a location of type <see cref="string"/>, the assumption is
    /// that the string represents a fully qualified type name.
    ///
    /// If the attribute is applied to a method it's treated as a special case and it implies
    /// the attribute should be applied to the "this" parameter of the method. As such the attribute
    /// should only be used on instance methods of types assignable to System.Type (or string, but no methods
    /// will use it there).
    /// </remarks>
    [AttributeUsage(
        AttributeTargets.Field | AttributeTargets.ReturnValue | AttributeTargets.GenericParameter |
        AttributeTargets.Parameter | AttributeTargets.Property | AttributeTargets.Method,
        Inherited = false)]
    internal sealed class DynamicallyAccessedMembersAttribute : Attribute
    {
        /// <summary>
        /// Initializes a new instance of the <see cref="DynamicallyAccessedMembersAttribute"/> class
        /// with the specified member types.
        /// </summary>
        /// <param name="memberTypes">The types of members dynamically accessed.</param>
        public DynamicallyAccessedMembersAttribute(DynamicallyAccessedMemberTypes memberTypes)
        {
            MemberTypes = memberTypes;
        }

        /// <summary>
        /// Gets the <see cref="DynamicallyAccessedMemberTypes"/> which specifies the type
        /// of members dynamically accessed.
        /// </summary>
        public DynamicallyAccessedMemberTypes MemberTypes { get; }
    }

    /// <summary>
    /// Specifies the types of members that are dynamically accessed.
    ///
    /// This enumeration has a <see cref="FlagsAttribute"/> attribute that allows a
    /// bitwise combination of its member values.
    /// </summary>
    [Flags]
    internal enum DynamicallyAccessedMemberTypes
    {
        /// <summary>
        /// Specifies no members.
        /// </summary>
        None = 0,

        /// <summary>
        /// Specifies the default, parameterless public constructor.
        /// </summary>
        PublicParameterlessConstructor = 0x0001,

        /// <summary>
        /// Specifies all public constructors.
        /// </summary>
        PublicConstructors = 0x0002 | PublicParameterlessConstructor,

        /// <summary>
        /// Specifies all non-public constructors.
        /// </summary>
        NonPublicConstructors = 0x0004,

        /// <summary>
        /// Specifies all public methods.
        /// </summary>
        PublicMethods = 0x0008,

        /// <summary>
        /// Specifies all non-public methods.
        /// </summary>
        NonPublicMethods = 0x0010,

        /// <summary>
        /// Specifies all public fields.
        /// </summary>
        PublicFields = 0x0020,

        /// <summary>
        /// Specifies all non-public fields.
        /// </summary>
        NonPublicFields = 0x0040,

        /// <summary>
        /// Specifies all public nested types.
        /// </summary>
        PublicNestedTypes = 0x0080,

        /// <summary>
        /// Specifies all non-public nested types.
        /// </summary>
        NonPublicNestedTypes = 0x0100,

        /// <summary>
        /// Specifies all public properties.
        /// </summary>
        PublicProperties = 0x0200,

        /// <summary>
        /// Specifies all non-public properties.
        /// </summary>
        NonPublicProperties = 0x0400,

        /// <summary>
        /// Specifies all public events.
        /// </summary>
        PublicEvents = 0x0800,

        /// <summary>
        /// Specifies all non-public events.
        /// </summary>
        NonPublicEvents = 0x1000,

        /// <summary>
        /// Specifies all members.
        /// </summary>
        All = ~None
    }
}
