//******************************************************************************************************//  WeakAction.cs - Gbtc////  Copyright © 2016, Grid Protection Alliance.  All Rights Reserved.////  Licensed to the Grid Protection Alliance (GPA) under one or more contributor license agreements. See//  the NOTICE file distributed with this work for additional information regarding copyright ownership.//  The GPA licenses this file to you under the MIT License (MIT), 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.opensource.org/licenses/MIT////  Unless agreed to in writing, the subject software distributed under the License is distributed on an//  "AS-IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. Refer to the//  License for the specific language governing permissions and limitations.////  Code Modification History://  ----------------------------------------------------------------------------------------------------//  01/16/2013 - Steven E. Chisholm//       Generated original version of source code. //  11/03/2016 - Steven E. Chisholm//       Modified the class to not require a local reference be kept by compiling the method //       to prevent that data from being collected.////****************************************************************************************************** using System;using System.Diagnostics.CodeAnalysis;using System.Runtime.CompilerServices;using GSF.Reflection; namespace GSF.Threading{    /// <summary>    /// Provides a weak referenced <see cref="Action"/> delegate.    /// </summary>    /// <remarks>    /// This class will store the information necessary so the callback    /// object will have a weak reference to it. This information is compiled    /// an can be quickly executed without the overhead of using reflection.    /// </remarks>    [SuppressMessage("Microsoft.Usage", "CA2237:MarkISerializableTypesWithSerializable")]    public class WeakAction : NullableWeakReference    {        private bool m_isStatic;        private readonly Action<object> m_compiledMethod;        /// <summary>        /// Creates a WeakAction.        /// </summary>        /// <param name="callback">The callback.</param>        public WeakAction(Action callback)            : base(callback.Target)        {            m_isStatic = callback.Method.IsStatic;            m_compiledMethod = callback.Method.CreateAction();        }         /// <summary>        /// Attempts to invoke the delegate to a weak reference object.        /// </summary>        /// <returns><c>true</c> if successful; otherwise, <c>false</c>.</returns>        [MethodImpl(MethodImplOptions.NoInlining)]        public bool TryInvoke()        {            if (m_isStatic)            {                m_compiledMethod(null);                return true;            }             object target = Target;             if ((object)target == null)                return false;             m_compiledMethod(target);             return true;        }         /// <summary>        /// Clears <see cref="Action"/> callback target.        /// </summary>        public override void Clear()        {            //Note, the race condition that exists here would simply cause            //A static method exit anyway since Target is always null for static             //methods.            m_isStatic = false;            base.Clear();        }    }     /// <summary>    /// Provides a weak referenced <see cref="Action"/> delegate.    /// </summary>    /// <remarks>    /// This class will store the information necessary so the callback    /// object will have a weak reference to it. This information is compiled    /// an can be quickly executed without the overhead of using reflection.    /// </remarks>    [SuppressMessage("Microsoft.Usage", "CA2237:MarkISerializableTypesWithSerializable")]    public class WeakAction<T> : NullableWeakReference    {        private bool m_isStatic;        private readonly Action<object,T> m_compiledMethod;        /// <summary>        /// Creates a WeakAction.        /// </summary>        /// <param name="callback">The callback.</param>        public WeakAction(Action<T> callback)            : base(callback.Target)        {            m_isStatic = callback.Method.IsStatic;            m_compiledMethod = callback.Method.CreateAction<T>();        }         /// <summary>        /// Attempts to invoke the delegate to a weak reference object.        /// </summary>        /// <returns><c>true</c> if successful; otherwise, <c>false</c>.</returns>        [MethodImpl(MethodImplOptions.NoInlining)]        public bool TryInvoke(T param1)        {            if (m_isStatic)            {                m_compiledMethod(null, param1);                return true;            }             object target = Target;             if ((object)target == null)                return false;              m_compiledMethod(target, param1);            return true;        }         /// <summary>        /// Clears <see cref="Action"/> callback target.        /// </summary>        public override void Clear()        {            //Note, the race condition that exists here would simply cause            //A static method exit anyway since Target is always null for static             //methods.            m_isStatic = false;            base.Clear();        }    } }