Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.Activities/System/Activities/Runtime/CompletionBookmark.cs

@@ -0,0 +1,59 @@
+//-----------------------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+//-----------------------------------------------------------------------------
+
+namespace System.Activities.Runtime
+{
+    using System;
+    using System.Runtime;
+    using System.Runtime.Serialization;
+    using System.Collections.Generic;
+
+    [DataContract]
+    class CompletionBookmark
+    {
+        CompletionCallbackWrapper callbackWrapper;
+
+        public CompletionBookmark()
+        {
+            // Called when we want to use the special completion callback
+        }
+
+        public CompletionBookmark(CompletionCallbackWrapper callbackWrapper)
+        {
+            this.callbackWrapper = callbackWrapper;
+        }
+
+        [DataMember(EmitDefaultValue = false, Name = "callbackWrapper")]
+        internal CompletionCallbackWrapper SerializedCallbackWrapper
+        {
+            get { return this.callbackWrapper; }
+            set { this.callbackWrapper = value; }
+        }
+
+        public void CheckForCancelation()
+        {
+            Fx.Assert(this.callbackWrapper != null, "We must have a callback wrapper if we are calling this.");
+            this.callbackWrapper.CheckForCancelation();
+        }
+
+        public WorkItem GenerateWorkItem(ActivityInstance completedInstance, ActivityExecutor executor)
+        {
+            if (this.callbackWrapper != null)
+            {
+                return this.callbackWrapper.CreateWorkItem(completedInstance, executor);
+            }
+            else
+            {
+                // Variable defaults and argument expressions always have a parent
+                // and never have a CompletionBookmark
+                if (completedInstance.State != ActivityInstanceState.Closed && completedInstance.Parent.HasNotExecuted)
+                {
+                    completedInstance.Parent.SetInitializationIncomplete();
+                }
+
+                return new EmptyWithCancelationCheckWorkItem(completedInstance.Parent, completedInstance);
+            }
+        }
+    }
+}