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using System;
using System.Threading;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Collections.ObjectModel;
using System.Workflow.Runtime;
using System.Diagnostics;
using System.Globalization;
namespace System.Workflow.Runtime.Hosting
{
[Obsolete("The System.Workflow.* types are deprecated. Instead, please use the new types from System.Activities.*")]
public class ManualWorkflowSchedulerService : WorkflowSchedulerService
{
private class CallbackInfo
{
WaitCallback callback;
Guid instanceId;
Guid timerId;
DateTime when;
public CallbackInfo(WaitCallback callback, Guid instanceId, Guid timerId, DateTime when)
{
this.callback = callback;
this.when = when;
this.instanceId = instanceId;
this.timerId = timerId;
}
public DateTime When
{
get { return when; }
}
public bool IsExpired
{
get { return DateTime.UtcNow >= when; }
}
public Guid InstanceId { get { return instanceId; } }
public Guid TimerId { get { return timerId; } }
public WaitCallback Callback
{
get { return callback; }
}
}
private KeyedPriorityQueue<Guid, CallbackInfo, DateTime> pendingScheduleRequests = new KeyedPriorityQueue<Guid, CallbackInfo, DateTime>();
private Dictionary<Guid, DefaultWorkflowSchedulerService.WorkItem> scheduleRequests = new Dictionary<Guid, DefaultWorkflowSchedulerService.WorkItem>();
private object locker = new Object();
private Timer callbackTimer;
private readonly TimerCallback timerCallback; // non-null indicates that active timers are enabled
private volatile bool threadRunning; // indicates that the timer thread is running
private static TimeSpan infinite = new TimeSpan(Timeout.Infinite);
private IList<PerformanceCounter> queueCounters;
private static TimeSpan fiveMinutes = new TimeSpan(0, 5, 0);
private const string USE_ACTIVE_TIMERS_KEY = "UseActiveTimers";
// Note that pendingScheduleRequests are keyed by instance ID under the assertion that there is at most one outstanding
// timer for any given instance ID. To support cancellation, and additional map is kept of timerID-to-instanceID so that
// we can find the appropriate pending given a timer ID
public ManualWorkflowSchedulerService()
{
}
public ManualWorkflowSchedulerService(bool useActiveTimers)
{
if (useActiveTimers)
{
timerCallback = new TimerCallback(OnTimerCallback);
pendingScheduleRequests.FirstElementChanged += OnFirstElementChanged;
WorkflowTrace.Host.TraceEvent(TraceEventType.Information, 0, "ManualWorkflowSchedulerService: started with active timers");
}
}
public ManualWorkflowSchedulerService(NameValueCollection parameters)
{
if (parameters == null)
throw new ArgumentNullException("parameters");
foreach (string key in parameters.Keys)
{
if (key == null)
throw new ArgumentException(String.Format(Thread.CurrentThread.CurrentCulture, ExecutionStringManager.UnknownConfigurationParameter, "null"));
string p = parameters[key];
if (!key.Equals(USE_ACTIVE_TIMERS_KEY, StringComparison.OrdinalIgnoreCase))
throw new ArgumentException(String.Format(Thread.CurrentThread.CurrentCulture, ExecutionStringManager.UnknownConfigurationParameter, key));
bool useActiveTimers;
if (!bool.TryParse(p, out useActiveTimers))
throw new FormatException(USE_ACTIVE_TIMERS_KEY);
if (useActiveTimers)
{
timerCallback = new TimerCallback(OnTimerCallback);
pendingScheduleRequests.FirstElementChanged += OnFirstElementChanged;
WorkflowTrace.Host.TraceEvent(TraceEventType.Information, 0, "ManualWorkflowSchedulerService: Started with active timers");
}
}
}
internal protected override void Schedule(WaitCallback callback, Guid workflowInstanceId)
{
if (callback == null)
throw new ArgumentNullException("callback");
if (workflowInstanceId.Equals(Guid.Empty))
throw new ArgumentException(String.Format(CultureInfo.CurrentCulture, ExecutionStringManager.CantBeEmptyGuid, "workflowInstanceId"));
lock (locker)
{
WorkflowTrace.Host.TraceEvent(TraceEventType.Information, 0, "ManualWorkflowSchedulerService: Schedule workflow {0}", workflowInstanceId);
if (!scheduleRequests.ContainsKey(workflowInstanceId))
scheduleRequests.Add(workflowInstanceId, new DefaultWorkflowSchedulerService.WorkItem(callback, workflowInstanceId));
}
if (queueCounters != null)
{
foreach (PerformanceCounter p in queueCounters)
{
p.RawValue = scheduleRequests.Count;
}
}
}
internal protected override void Schedule(WaitCallback callback, Guid workflowInstanceId, DateTime whenUtc, Guid timerId)
{
if (callback == null)
throw new ArgumentNullException("callback");
if (workflowInstanceId.Equals(Guid.Empty))
throw new ArgumentException(String.Format(CultureInfo.CurrentCulture, ExecutionStringManager.CantBeEmptyGuid, "workflowInstanceId"));
if (timerId.Equals(Guid.Empty))
throw new ArgumentException(String.Format(CultureInfo.CurrentCulture, ExecutionStringManager.CantBeEmptyGuid, "timerId"));
lock (locker)
{
WorkflowTrace.Host.TraceEvent(TraceEventType.Information, 0, "ManualWorkflowSchedulerService: Schedule timer {0} for workflow {1} at {2}", timerId, workflowInstanceId, whenUtc);
pendingScheduleRequests.Enqueue(timerId, new CallbackInfo(callback, workflowInstanceId, timerId, whenUtc), whenUtc);
}
}
internal protected override void Cancel(Guid timerId)
{
if (timerId.Equals(Guid.Empty))
throw new ArgumentException(String.Format(CultureInfo.CurrentCulture, ExecutionStringManager.CantBeEmptyGuid, "timerId"));
lock (locker)
{
WorkflowTrace.Host.TraceEvent(TraceEventType.Information, 0, "ManualWorkflowSchedulerService: Cancel timer {0}", timerId);
pendingScheduleRequests.Remove(timerId);
}
}
private bool RunOne(Guid workflowInstanceId)
{
bool retval = false;
DefaultWorkflowSchedulerService.WorkItem cs = null;
lock (locker)
{
if (scheduleRequests.ContainsKey(workflowInstanceId))
{
cs = scheduleRequests[workflowInstanceId];
scheduleRequests.Remove(workflowInstanceId);
}
}
try
{
if (cs != null)
{
WorkflowTrace.Host.TraceEvent(TraceEventType.Information, 0, "ManualWorkflowSchedulerService: Executing {0}", workflowInstanceId);
if (queueCounters != null)
{
foreach (PerformanceCounter p in queueCounters)
{
p.RawValue = scheduleRequests.Count;
}
}
cs.Invoke(this);
retval = true;
}
}
catch (Exception e)
{
RaiseServicesExceptionNotHandledEvent(e, workflowInstanceId);
}
return retval;
}
private bool HasExpiredTimer(Guid workflowInstanceId, out Guid timerId)
{
lock (locker)
{
CallbackInfo ci = pendingScheduleRequests.FindByPriority(DateTime.UtcNow,
delegate(CallbackInfo c) { return c.InstanceId == workflowInstanceId; });
if (ci != null)
{
timerId = ci.TimerId;
return true;
}
}
timerId = Guid.Empty;
return false;
}
private bool ProcessTimer(Guid workflowInstanceId)
{
bool retval = false;
CallbackInfo cs = null;
Guid timerId = Guid.Empty;
lock (locker)
{
Guid expTimerId;
if (HasExpiredTimer(workflowInstanceId, out expTimerId))
{
cs = pendingScheduleRequests.Remove(expTimerId);
}
}
try
{
if (cs != null)
{
WorkflowTrace.Host.TraceEvent(TraceEventType.Information, 0, "ManualWorkflowSchedulerService: Processing timer {0}", timerId);
cs.Callback(cs.InstanceId);
retval = true;
}
}
catch (Exception e)
{
RaiseServicesExceptionNotHandledEvent(e, workflowInstanceId);
}
return retval;
}
private bool CanRun(Guid workflowInstanceId)
{
bool retval = false;
lock (locker)
{
Guid timerId;
retval = scheduleRequests.ContainsKey(workflowInstanceId) || HasExpiredTimer(workflowInstanceId, out timerId);
WorkflowTrace.Host.TraceEvent(TraceEventType.Information, 0, "ManualWorkflowSchedulerService: CanRun is {0}", retval);
}
return retval;
}
public bool RunWorkflow(Guid workflowInstanceId)
{
if (workflowInstanceId.Equals(Guid.Empty))
throw new ArgumentException(String.Format(CultureInfo.CurrentCulture, ExecutionStringManager.CantBeEmptyGuid, "workflowInstanceId"));
WorkflowTrace.Host.TraceEvent(TraceEventType.Information, 0, "ManualWorkflowSchedulerService: Running workflow {0}", workflowInstanceId);
bool retval = false; // return true if we do any work at all
while (CanRun(workflowInstanceId))
{
if (RunOne(workflowInstanceId) || ProcessTimer(workflowInstanceId))
retval = true; // did some work, try again
else
break; // no work done this iteration
}
return retval;
}
private Timer CreateTimerCallback(CallbackInfo info)
{
DateTime now = DateTime.UtcNow;
TimeSpan span = (info.When > now) ? info.When - now : TimeSpan.Zero;
// never let more than five minutes go by without checking
if (span > fiveMinutes)
{
span = fiveMinutes;
}
return new Timer(timerCallback, info.InstanceId, span, infinite);
}
override protected void OnStarted()
{
base.OnStarted();
if (this.timerCallback != null)
{
lock (locker)
{
CallbackInfo ci = pendingScheduleRequests.Peek();
if (ci != null)
callbackTimer = CreateTimerCallback(ci);
}
}
lock (locker)
{
if (queueCounters == null && this.Runtime.PerformanceCounterManager != null)
{
queueCounters = this.Runtime.PerformanceCounterManager.CreateCounters(ExecutionStringManager.PerformanceCounterWorkflowsWaitingName);
}
}
}
protected internal override void Stop()
{
base.Stop();
if (this.timerCallback != null)
{
lock (locker)
{
if (callbackTimer != null)
{
callbackTimer.Dispose();
callbackTimer = null;
}
}
}
}
private void OnTimerCallback(object ignored)
{
CallbackInfo ci = null;
try
{
lock (locker)
{
if (State.Equals(WorkflowRuntimeServiceState.Started))
{
ci = pendingScheduleRequests.Peek();
if (ci != null)
{
if (ci.IsExpired)
{
WorkflowTrace.Host.TraceEvent(TraceEventType.Information, 0, "Timeout occured for timer for instance {0}", ci.InstanceId);
threadRunning = true;
pendingScheduleRequests.Dequeue();
}
else
{
callbackTimer = CreateTimerCallback(ci);
}
}
}
}
if (threadRunning)
{
ci.Callback(ci.InstanceId); // delivers the timer message
RunWorkflow(ci.InstanceId);
}
}
catch (ThreadAbortException e)
{
WorkflowTrace.Host.TraceEvent(TraceEventType.Error, 0, "Timeout for instance, {0} threw exception {1}", ci == null ? Guid.Empty : ci.InstanceId, e.Message);
RaiseServicesExceptionNotHandledEvent(e, ci.InstanceId);
throw;
}
catch (Exception e)
{
WorkflowTrace.Host.TraceEvent(TraceEventType.Error, 0, "Timeout for instance, {0} threw exception {1}", ci == null ? Guid.Empty : ci.InstanceId, e.Message);
RaiseServicesExceptionNotHandledEvent(e, ci.InstanceId);
}
finally
{
lock (locker)
{
if (threadRunning)
{
threadRunning = false;
ci = pendingScheduleRequests.Peek();
if (ci != null)
callbackTimer = CreateTimerCallback(ci);
}
}
}
}
private void OnFirstElementChanged(object source, KeyedPriorityQueueHeadChangedEventArgs<CallbackInfo> e)
{
lock (locker)
{
if (threadRunning)
return; // ignore when a timer thread is already processing a timer request
if (callbackTimer != null)
{
callbackTimer.Dispose();
callbackTimer = null;
}
if (e.NewFirstElement != null && this.State == WorkflowRuntimeServiceState.Started)
{
callbackTimer = CreateTimerCallback(e.NewFirstElement);
}
}
}
}
}
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