Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.Workflow.ComponentModel/AuthoringOM/Sequence.cs

@@ -0,0 +1,130 @@
+namespace System.Workflow.ComponentModel
+{
+    #region Imports
+
+    using System;
+    using System.Text;
+    using System.Reflection;
+    using System.Collections;
+    using System.CodeDom;
+    using System.ComponentModel;
+    using System.ComponentModel.Design;
+    using System.Drawing;
+    using System.Workflow.ComponentModel;
+    using System.Workflow.ComponentModel.Design;
+    using System.Collections.Generic;
+    using System.Workflow.ComponentModel.Compiler;
+
+    #endregion
+
+    internal static class SequenceHelper
+    {
+        private static DependencyProperty ActiveChildQualifiedNameProperty = DependencyProperty.RegisterAttached("ActiveChildQualifiedName", typeof(String), typeof(SequenceHelper));
+        private static DependencyProperty ActiveChildRemovedProperty = DependencyProperty.RegisterAttached("ActiveChildRemoved", typeof(bool), typeof(SequenceHelper), new PropertyMetadata(DependencyPropertyOptions.NonSerialized));
+
+        public static ActivityExecutionStatus Execute(CompositeActivity activity, ActivityExecutionContext executionContext)
+        {
+            if (activity.EnabledActivities.Count == 0)
+                return ActivityExecutionStatus.Closed;
+            else
+            {
+                activity.EnabledActivities[0].RegisterForStatusChange(Activity.ClosedEvent, (IActivityEventListener<ActivityExecutionStatusChangedEventArgs>)activity);
+                executionContext.ExecuteActivity(activity.EnabledActivities[0]);
+                activity.SetValue(ActiveChildQualifiedNameProperty, activity.EnabledActivities[0].QualifiedName);
+                return ActivityExecutionStatus.Executing;
+            }
+        }
+
+        public static ActivityExecutionStatus Cancel(CompositeActivity activity, ActivityExecutionContext executionContext)
+        {
+            for (int i = (activity.EnabledActivities.Count - 1); i >= 0; i--)
+            {
+                Activity childActivity = activity.EnabledActivities[i];
+
+                if (childActivity.ExecutionStatus == ActivityExecutionStatus.Executing)
+                {
+                    executionContext.CancelActivity(childActivity);
+                    return activity.ExecutionStatus;
+                }
+
+                if (childActivity.ExecutionStatus == ActivityExecutionStatus.Canceling ||
+                    childActivity.ExecutionStatus == ActivityExecutionStatus.Faulting)
+                {
+                    return activity.ExecutionStatus;
+                }
+
+                if (childActivity.ExecutionStatus == ActivityExecutionStatus.Closed)
+                {
+                    activity.RemoveProperty(ActiveChildQualifiedNameProperty);
+                    return ActivityExecutionStatus.Closed;
+                }
+            }
+            return ActivityExecutionStatus.Closed;
+        }
+
+        public static void OnEvent(CompositeActivity activity, Object sender, ActivityExecutionStatusChangedEventArgs e)
+        {
+            ActivityExecutionContext context = sender as ActivityExecutionContext;
+            e.Activity.UnregisterForStatusChange(Activity.ClosedEvent, (IActivityEventListener<ActivityExecutionStatusChangedEventArgs>)activity);
+
+            if (activity.ExecutionStatus == ActivityExecutionStatus.Canceling ||
+                activity.ExecutionStatus == ActivityExecutionStatus.Faulting ||
+                activity.ExecutionStatus == ActivityExecutionStatus.Executing && !TryScheduleNextChild(activity, context))
+            {
+                activity.RemoveProperty(ActiveChildQualifiedNameProperty);
+                context.CloseActivity();
+            }
+        }
+
+        private static bool TryScheduleNextChild(CompositeActivity activity, ActivityExecutionContext executionContext)
+        {
+            IList<Activity> children = activity.EnabledActivities;
+
+            // Find index of next activity to run.
+            int indexOfNextActivity = 0;
+            for (int i = (children.Count - 1); i >= 0; i--)
+            {
+                if (children[i].ExecutionStatus == ActivityExecutionStatus.Closed)
+                {
+                    // Check whether this is last child?
+                    if (i == (children.Count - 1))
+                        return false;
+
+                    indexOfNextActivity = i + 1;
+                    break;
+                }
+            }
+
+            children[indexOfNextActivity].RegisterForStatusChange(Activity.ClosedEvent, (IActivityEventListener<ActivityExecutionStatusChangedEventArgs>)activity);
+            executionContext.ExecuteActivity(children[indexOfNextActivity]);
+            activity.SetValue(ActiveChildQualifiedNameProperty, children[indexOfNextActivity].QualifiedName);
+            return true;
+        }
+
+        public static void OnActivityChangeRemove(CompositeActivity activity, ActivityExecutionContext executionContext, Activity removedActivity)
+        {
+            String activeChildQualifiedName = activity.GetValue(ActiveChildQualifiedNameProperty) as String;
+
+            if (removedActivity.QualifiedName.Equals(activeChildQualifiedName))
+                activity.SetValue(ActiveChildRemovedProperty, true);
+        }
+
+        public static void OnWorkflowChangesCompleted(CompositeActivity activity, ActivityExecutionContext executionContext)
+        {
+            String activeChildQualifiedName = activity.GetValue(ActiveChildQualifiedNameProperty) as String;
+            bool activeChildRemovedInDynamicUpdate = (bool)activity.GetValue(ActiveChildRemovedProperty);
+
+            if (activeChildQualifiedName != null && activeChildRemovedInDynamicUpdate)
+            {   //We have our active child removed.    
+                if (activity.ExecutionStatus == ActivityExecutionStatus.Canceling ||
+                activity.ExecutionStatus == ActivityExecutionStatus.Faulting ||
+                activity.ExecutionStatus == ActivityExecutionStatus.Executing && !TryScheduleNextChild(activity, executionContext))
+                {
+                    activity.RemoveProperty(ActiveChildQualifiedNameProperty);
+                    executionContext.CloseActivity();
+                }
+            }
+            activity.RemoveProperty(ActiveChildRemovedProperty);
+        }
+    }
+}