/// <summary>
/// Get value synchronouslym, if factory is async then factory is run in a background task.
/// </summary>
public Typename GetValue()
{
// shortcut
if (_isValueCreated)
{
return(_value);
}
// if we're here there is no value.. yet, synchronize!
_lock.Run(() =>
{
// check again, maybe it was created
if (_isValueCreated)
{
return;
}
// sync factory
if (_factory != null)
{
_value = _factory();
// destroy fields that are not needed anymore
_factory = null;
}
// async factory
if (_asyncFactory != null)
{
// yes this blocks the thread, you called the sync version
// but it does it on a background thread
_value = _asyncFactory().Result;
// destroy fields that are not needed anymore
_asyncFactory = null;
}
_isValueCreated = true;
});
return(_value);
}
public void ByDefaultOnlyOneThreadCanEnter()
{
int counter = 0;
var criticalSection = new AsyncLazy.AsyncLock();
;
var threads = Enumerable.Range(1, 10).Select(n => new Thread(() => criticalSection.Run(() =>
{
counter++;
counter.Should().Be(1);
counter--;
}))).ToList();
threads.ForEach(thread => thread.Start());
threads.ForEach(thread => thread.Join());
counter.Should().Be(0);
}