/// <summary>
/// Initialize the callback holding object.
/// </summary>
/// <param name="workItemsGroup">The workItemGroup of the workitem</param>
/// <param name="workItemInfo">The WorkItemInfo of te workitem</param>
/// <param name="callback">Callback delegate for the callback.</param>
/// <param name="state">State with which to call the callback delegate.</param>
///
/// We assume that the WorkItem object is created within the thread
/// that meant to run the callback
public WorkItem(
IWorkItemsGroup workItemsGroup,
WorkItemInfo workItemInfo,
WorkItemCallback callback,
object state)
{
_workItemsGroup = workItemsGroup;
_workItemInfo = workItemInfo;
if (_workItemInfo.UseCallerCallContext || _workItemInfo.UseCallerHttpContext)
{
_callerContext = CallerThreadContext.Capture(_workItemInfo.UseCallerCallContext, _workItemInfo.UseCallerHttpContext);
}
_callback = callback;
_state = state;
_workItemResult = new WorkItemResult(this);
Initialize();
}
/// <summary>
/// Execute the work item
/// </summary>
private void ExecuteWorkItem()
{
CallerThreadContext ctc = null;
if (null != _callerContext)
{
ctc = CallerThreadContext.Capture(_callerContext.CapturedCallContext, _callerContext.CapturedHttpContext);
CallerThreadContext.Apply(_callerContext);
}
Exception exception = null;
object result = null;
try
{
try
{
result = _callback(_state);
}
catch (Exception e)
{
// Save the exception so we can rethrow it later
exception = e;
}
// Remove the value of the execution thread, so it will be impossible to cancel the work item,
// since it is already completed.
// Cancelling a work item that already completed may cause the abortion of the next work item!!!
Thread executionThread = Interlocked.CompareExchange(ref _executingThread, null, _executingThread);
if (null == executionThread)
{
// Oops! we are going to be aborted..., Wait here so we can catch the ThreadAbortException
Thread.Sleep(60 * 1000);
// If after 1 minute this thread was not aborted then let it continue working.
}
}
// We must treat the ThreadAbortException or else it will be stored in the exception variable
catch (ThreadAbortException tae)
{
tae.GetHashCode();
// Check if the work item was cancelled
// If we got a ThreadAbortException and the CTP is not shutting down, it means the
// work items was cancelled.
if (!CThreadPool.CurrentThreadEntry.AssociatedCThreadPool.IsShuttingdown)
{
Thread.ResetAbort();
}
}
if (null != _callerContext)
{
CallerThreadContext.Apply(ctc);
}
if (!CThreadPool.IsWorkItemCanceled)
{
SetResult(result, exception);
}
}