mcs/class/referencesource/System.Workflow.Runtime/WorkflowStateRollbackService.cs

   1 using System;
   2 using System.Collections.Generic;
   3 using System.Collections;
   4 using System.Diagnostics;
   5 using System.Reflection;
   6 using System.Text;
   7 using System.IO;
   8 using System.IO.Compression;
   9 using System.Transactions;
  10 using System.Workflow.ComponentModel;
  11
  12 namespace System.Workflow.Runtime
  13 {
  14     internal sealed class WorkflowStateRollbackService
  15     {
  16         WorkflowExecutor workflowExecutor;
  17
  18         // cache the revert back data
  19         MemoryStream clonedInstanceStateStream;
  20         Activity workflowDefinition = null;
  21         bool isInstanceStateRevertRequested = false;
  22
  23         // revert back notification info
  24         string activityQualifiedName;
  25         int activityContextId;
  26         EventArgs callbackData;
  27         EventHandler<EventArgs> callbackHandler;
  28         bool suspendOnRevert;
  29         string suspendOnRevertInfo;
  30
  31         Hashtable completedContextActivities = new Hashtable();
  32
  33         public WorkflowStateRollbackService(WorkflowExecutor workflowExecutor)
  34         {
  35             this.workflowExecutor = workflowExecutor;
  36         }
  37
  38         internal bool IsInstanceStateRevertRequested
  39         {
  40             get { return this.isInstanceStateRevertRequested; }
  41         }
  42
  43         internal void CheckpointInstanceState()
  44         {
  45             Debug.Assert(this.workflowExecutor.InstanceId != null, "instance id null at checkpoint time");
  46
  47             // serialize the instance state
  48             this.clonedInstanceStateStream = new MemoryStream(10240);
  49             this.workflowExecutor.RootActivity.Save(this.clonedInstanceStateStream);
  50             this.workflowDefinition = this.workflowExecutor.WorkflowDefinition;
  51             this.completedContextActivities = (Hashtable)this.workflowExecutor.CompletedContextActivities.Clone();
  52             this.clonedInstanceStateStream.Position = 0;
  53         }
  54
  55         internal void RequestRevertToCheckpointState(Activity currentActivity, EventHandler<EventArgs> callbackHandler, EventArgs callbackData, bool suspendOnRevert, string suspendInfo)
  56         {
  57             if (this.clonedInstanceStateStream == null)
  58                 throw new InvalidOperationException(ExecutionStringManager.InvalidRevertRequest);
  59
  60             // cache the after revert information
  61             this.activityContextId = ContextActivityUtils.ContextId(ContextActivityUtils.ContextActivity(currentActivity));
  62             this.activityQualifiedName = currentActivity.QualifiedName;
  63             this.callbackData = callbackData;
  64             this.callbackHandler = callbackHandler;
  65             this.suspendOnRevert = suspendOnRevert;
  66             this.suspendOnRevertInfo = suspendInfo;
  67
  68             // ask scheduler to stop
  69             this.isInstanceStateRevertRequested = true;
  70             this.workflowExecutor.Scheduler.CanRun = false;
  71         }
  72
  73         internal void DisposeCheckpointState()
  74         {
  75             this.clonedInstanceStateStream = null;
  76         }
  77
  78         internal void RevertToCheckpointState()
  79         {
  80             Debug.Assert(this.clonedInstanceStateStream != null, "cloned instance-state stream null at restore time");
  81
  82             // deserialize only on first access
  83             Activity clonedRootActivity = null;
  84             this.clonedInstanceStateStream.Position = 0;
  85             using (RuntimeEnvironment runtimeEnv = new RuntimeEnvironment(this.workflowExecutor.WorkflowRuntime))
  86             {
  87                 clonedRootActivity = Activity.Load(this.clonedInstanceStateStream, (Activity)this.workflowDefinition);
  88             }
  89             Debug.Assert(clonedRootActivity != null);
  90             //
  91             // Set the trackingListenerBroker before initializing the executor so the tracking
  92             // runtime gets a reference to the correct object
  93             clonedRootActivity.SetValue(WorkflowExecutor.TrackingListenerBrokerProperty, workflowExecutor.RootActivity.GetValue(WorkflowExecutor.TrackingListenerBrokerProperty));
  94
  95             // create the new workflowExecutor
  96             WorkflowExecutor newWorkflowExecutor = new WorkflowExecutor(Guid.Empty);    // use a dummy guid while swapping executors
  97             newWorkflowExecutor.Initialize(clonedRootActivity, this.workflowExecutor.WorkflowRuntime, this.workflowExecutor);
  98
  99             // enqueue the activity notifier
 100             Activity activityContext = newWorkflowExecutor.GetContextActivityForId(this.activityContextId);
 101             Activity activity = activityContext.GetActivityByName(this.activityQualifiedName);
 102             using (new ServiceEnvironment(activity))
 103             {
 104                 using (newWorkflowExecutor.SetCurrentActivity(activity))
 105                 {
 106                     using (ActivityExecutionContext executionContext = new ActivityExecutionContext(activity))
 107                         executionContext.Invoke<EventArgs>(this.callbackHandler, this.callbackData);
 108                 }
 109             }
 110             //
 111             // Push the batch item ordering id to the new instance
 112             newWorkflowExecutor.BatchCollection.WorkItemOrderId = this.workflowExecutor.BatchCollection.WorkItemOrderId;
 113             // replace pending batch items
 114             foreach (KeyValuePair<object, WorkBatch> batch in this.workflowExecutor.BatchCollection)
 115             {
 116                 batch.Value.SetWorkBatchCollection(newWorkflowExecutor.BatchCollection);
 117                 Activity oldActivity = batch.Key as Activity;
 118                 // no need to add the transient state batch
 119                 if (oldActivity != null)
 120                 {
 121                     Activity newactivity = activityContext.GetActivityByName(oldActivity.QualifiedName);
 122                     newWorkflowExecutor.BatchCollection.Add(newactivity, batch.Value);
 123                 }
 124             }
 125             this.workflowExecutor.BatchCollection.Clear();
 126
 127             Debug.Assert(this.completedContextActivities != null);
 128             newWorkflowExecutor.CompletedContextActivities = this.completedContextActivities;
 129
 130             // replace with the WorkflowRuntime
 131             Debug.Assert(this.workflowExecutor.IsInstanceValid);
 132             this.workflowExecutor.WorkflowRuntime.ReplaceWorkflowExecutor(this.workflowExecutor.InstanceId, this.workflowExecutor, newWorkflowExecutor);
 133
 134             // now resume or suspend the scheduler as needed
 135             if (!this.suspendOnRevert)
 136             {
 137                 // get the new one going
 138                 newWorkflowExecutor.Scheduler.Resume();
 139             }
 140             else
 141             {
 142                 // this call will be old scheduler's thread
 143                 newWorkflowExecutor.SuspendOnIdle(this.suspendOnRevertInfo);
 144             }
 145             DisposeCheckpointState();
 146         }
 147     }
 148 }