Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.Activities/System/Activities/Statements/StateMachineExtension.cs

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+//------------------------------------------------------------------------------
+// <copyright file="StateMachineExtension.cs" company="Microsoft">
+//     Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>
+//------------------------------------------------------------------------------
+
+namespace System.Activities.Statements
+{
+    using System;
+    using System.Activities.Hosting;
+    using System.Collections.Generic;
+    using System.Linq;
+    using System.Runtime;
+    using System.Text;
+
+    /// <summary>
+    /// StateMachineExtension is used to resume a bookmark outside StateMachine.
+    /// </summary>
+    class StateMachineExtension : IWorkflowInstanceExtension
+    {
+        private WorkflowInstanceProxy instance;
+
+        /// <summary>
+        /// Used to get additional extensions.
+        /// </summary>
+        /// <returns>Returns a IEnumerable of extensions</returns>
+        public IEnumerable<object> GetAdditionalExtensions()
+        {
+            return null;
+        }
+
+        /// <summary>
+        /// called with the targe instance under WorkflowInstance.Initialize
+        /// </summary>
+        /// <param name="instance">The value of WorkflowInstanceProxy</param>
+        public void SetInstance(WorkflowInstanceProxy instance)
+        {
+            this.instance = instance;
+        }
+
+        /// <summary>
+        /// Used to resume bookmark outside workflow.
+        /// </summary>
+        /// <param name="bookmark">The value of Bookmark to be resumed</param>
+        public void ResumeBookmark(Bookmark bookmark)
+        {
+            // This method is necessary due to CSDMain 223257.
+            IAsyncResult asyncResult = this.instance.BeginResumeBookmark(bookmark, null, Fx.ThunkCallback(new AsyncCallback(StateMachineExtension.OnResumeBookmarkCompleted)), this.instance);
+            if (asyncResult.CompletedSynchronously)
+            {
+                this.instance.EndResumeBookmark(asyncResult);
+            }
+        }
+
+        static void OnResumeBookmarkCompleted(IAsyncResult result)
+        {
+            if (!result.CompletedSynchronously)
+            {
+                WorkflowInstanceProxy instance = result.AsyncState as WorkflowInstanceProxy;
+                Fx.Assert(instance != null, "BeginResumeBookmark should pass a WorkflowInstanceProxy object as the async state object.");
+                instance.EndResumeBookmark(result);
+            }
+        }
+    }
+}