private static void FinishInvoke(AsyncRes res)
{
if (res == null)
{
return;
}
try {
//finish a few more properties
res.isCompleted = true;
res.completeTime = DateTime.Now;
//set the resetevent, in case someone is using the waithandle to know when we have completed.
res.mre.Set();
} catch (Exception ex) {
Console.WriteLine("Error setting wait handle on " + (res.Method ?? "NULL") + ex);
}
if (res.RMode != ReenteranceMode.Allow)
{
//if mode is bypass or stack, then we must have a lock that needs releasing
try {
if (methodLocks.ContainsKey(res.Method))
{
Monitor.Exit(methodLocks[res.Method]);
}
} catch (Exception ex) {
Console.WriteLine("Error releasing reentrant lock on " + (res.Method ?? "NULL") + ex);
}
}
}
private static bool BeforeInvoke(AsyncRes res)
{
//if marked as completed then we abort.
if (res.IsCompleted)
{
return(false);
}
//if mode is 'allow' there is nothing to check. Otherwise...
if (res.RMode != ReenteranceMode.Allow)
{
//be threadsafe with our one and only member field
lock (methodLocks) {
if (!methodLocks.ContainsKey(res.Method))
{
//make sure we have a generic locking object in the collection, it will already be there if we are reentering
methodLocks.Add(res.Method, new object());
}
//if bypass mode and we can't get or lock, we dump out.
if (res.RMode == ReenteranceMode.Bypass)
{
if (!Monitor.TryEnter(methodLocks[res.Method]))
{
res.result = AsyncAction.Reenterant;
return(false);
}
}
else
{
//Otherwise in 'stack' mode, we just wait until someone else releases it...
Monitor.Enter(methodLocks[res.Method]);
}
//if we are here, all is good.
//Set some properties on the result class to show when we started, and what thread we are on
res.isStarted = true;
res.startTime = DateTime.Now;
res.thread = Thread.CurrentThread;
}
}
return(true);
}
/// <summary>
/// Fires off your delegate asyncronously, using the threadpool or a full managed thread if needed.
/// </summary>
/// <param name="d">A void delegate - can be cast to (Dlg) from an anonymous delgate.</param>
/// <param name="dr">A delegate with a return value of some sort - can be cast to (DlgR) from an anonymous delgate with a return.</param>
/// <param name="state">A user object that can be tracked through the returned result</param>
/// <param name="getRetVal">If true, and the method/delgete returns something, it is included in the AsyncRes returned (after the method completes)</param>
/// <param name="tryThreadPool">True to use the TP, otherwise just go to a ful lthread - good for long running tasks.</param>
/// <param name="rMode">If true, will make sure no other instances are running your method.</param>
/// <returns>AsyncRes with all kind o' goodies for waiting, result values, etc.</returns>
private static AsyncRes Do(DlgR dr, Dlg d, bool getRetVal, object state, bool tryThreadPool, ReenteranceMode rMode, Control control, bool async)
{
//get a generic MethodInfo for checks..
MethodInfo mi = ((dr != null) ? dr.Method : d.Method);
//make a unique key for output usage
string key = string.Format("{0}{1}{2}{3}", ((getRetVal) ? "<-" : ""), mi.DeclaringType, ((mi.IsStatic) ? ":" : "."), mi.Name);
//our custom return value, holds our delegate, state, key, etc.
AsyncRes res = new AsyncRes(state, ((dr != null) ? (Delegate)dr : (Delegate)d), key, rMode);
//Create a delegate wrapper for what we will actually invoke..
Dlg dlg = (Dlg) delegate {
if (!BeforeInvoke(res))
{
return; //checks for reentrance issues and sets us up
}
try {
if (res.IsCompleted)
{
return;
}
if (dr != null)
{
res.retVal = dr(); //use this one if theres a return
}
else
{
d(); //otherwise the simpler dlg
}
} catch (Exception ex) { //we never want a rogue exception on a random thread, it can't bubble up anywhere
Console.WriteLine("Async Exception:" + ex);
} finally {
FinishInvoke(res); //this will fire our callback if they used it, and clean up
}
};
if (control != null)
{
res.control = control;
res.result = AsyncAction.ControlInvoked;
if (!async)
{
if (!control.InvokeRequired)
{
res.completedSynchronously = true;
dlg();
}
else
{
control.Invoke(dlg);
}
}
else
{
control.BeginInvoke(dlg);
}
return(res);
} //don't catch these errors - if this fails, we shouldn't try a real thread or threadpool!
if (tryThreadPool) //we are going to use the .NET threadpool
{
try {
//get some stats - much better than trying and silently failing or throwing an expensive exception
int minThreads, minIO, threads, ioThreads, totalThreads, totalIO;
ThreadPool.GetMinThreads(out minThreads, out minIO);
ThreadPool.GetAvailableThreads(out threads, out ioThreads);
ThreadPool.GetMaxThreads(out totalThreads, out totalIO);
//check for at least our thread plus one more in ThreadPool
if (threads > minThreads)
{
//this is what actually fires this task off..
bool result = ThreadPool.QueueUserWorkItem((WaitCallback) delegate { dlg(); });
if (result)
{
res.result = AsyncAction.ThreadPool;
//this means success in queueing and running the item
return(res);
}
else
{
//according to docs, this "won't ever happen" - exception instead, but just for kicks.
Console.WriteLine("Failed to queue in threadpool.", "Method: " + key);
}
}
else
{
Console.WriteLine(String.Format("Insufficient idle threadpool threads: {0} of {1} - min {2}, Method: {3}", threads, totalThreads, minThreads, key));
}
} catch (Exception ex) {
Console.WriteLine("Failed to queue in threadpool: " + ex.Message, "Method: " + key);
}
}
//if we got this far, then something up there failed, or they wanted a dedicated thread
Thread t = new Thread((ThreadStart) delegate { dlg(); });
t.IsBackground = true; //this or threadpriority are candidates for additional settings
t.Name = "Async_" + key;
res.result = AsyncAction.Thread;
t.Start();
return(res);
}