public Task <INotifyDisposable> Lock()
{
//if (we are not locked)
//{
// return Task that is already finished
//} else {
// create task completion source, so we can return the token later
// and return the task
//}
lock (_mutex)
{
var token = Disposables.Call(Release);
if (_currentToken == null)
{
_currentToken = token;
return(_currentToken.ToTask());
}
else
{
var drt = token.ToDeferredTask();
_requests.Enqueue(drt);
return(drt.Task);
}
}
}
public static IObservable <T> AsObservable <T>(this INotifyDisposable disposable, Func <T> lastValue = null)
{
return(Observable.Create <T>(observer =>
{
if (disposable.IsDisposed)
{
if (lastValue != null)
{
observer.OnNext(lastValue());
}
observer.OnCompleted();
return Disposables.Empty;
}
var handler = Disposables.Call(() =>
{
if (lastValue != null)
{
observer.OnNext(lastValue());
}
observer.OnCompleted();
});
disposable.Attach(handler, keepAlive: true);
return Disposables.Call(() =>
{
disposable.Dettach(handler);
});
}));
}
/// <summary>
/// Creates an observable that yields an event when the property value changes. The event payload is the new
/// property value.
/// </summary>
public static IObservable <TProp> ObservePropertyValues <TBindable, TProp>(
this TBindable owner,
Expression <Func <TBindable, TProp> > property
)
where TBindable : BindableBase
{
var propInfo = property.GetProperty();
var getter = propInfo.AsGetter <TBindable, TProp>();
var value = getter(owner);
return(Observable.Create <TProp>(observer =>
{
owner.Observe <TProp>(propInfo.Name, val => observer.OnNext(val));
var handler = Disposables.Call(() => observer.OnCompleted());
owner.Attach(handler);
observer.OnNext(getter(owner));
return Disposables.Call(() =>
{
owner.Unobserve(propInfo.Name, owner);
owner.Dettach(handler);
});
}).ObserveOnDispatcher());
}
public static INotifyDisposable WhenDisposed(this INotifyDisposable source, Action action)
{
var call = Disposables.Call(action);
source.Attach(call, keepAlive: true);
return(source);
}
public Task <INotifyDisposable> Lock()
{
lock (_mutex)
{
var token = Disposables.Call(Release);
if (LocksCount < LocksLimit)
{
_currentTokens.Add(token);
return(token.ToTask());
}
else
{
var drt = token.ToDeferredTask();
_queue.Enqueue(drt);
return(drt.Task);
}
}
}
/// <summary>
/// Converts an AsyncEvent to IObservable of Unit (since there is not IObservable of void. Using the
/// owner to control the weak action lifespan and unsubscribe when observer is disposed
/// </summary>
/// <typeparam name="T"></typeparam>
/// <typeparam name="TOwner"></typeparam>
/// <param name="source"></param>
/// <param name="owner"></param>
/// <returns></returns>
public static IObservable <Unit> ToObservable <TOwner>(this AsyncEvent source, TOwner owner)
where TOwner : INotifyDisposable
{
return(Observable.Create <Unit>(async observer =>
{
Func <Task> handler = () =>
{
observer.OnNext(Unit.Default);
return Task.CompletedTask;
};
await source.Subscribe(owner, handler);
return Disposables.Call(() =>
{
source.Unsubscribe(owner, handler);
});
}));
}
/// <summary>
/// Subscribes to an IStateCollectionReader and exposes it as Observable of CollectionChanges
/// </summary>
public static IObservable <CollectionChanges <T> > ObserveChanges <T, TOwner>(this IStateCollectionReader <T> source, TOwner owner)
where TOwner : INotifyDisposable
{
return(Observable.Create <CollectionChanges <T> >(async observer =>
{
Func <CollectionChanges <T>, Task> handler = val =>
{
observer.OnNext(val);
return Task.CompletedTask;
};
await source.Changed.Subscribe(owner, handler);
return Disposables.Call(() =>
{
source.Changed.Unsubscribe(owner, handler);
});
}));
}
public Task <IDisposable> WriterLock()
{
lock (_mutex)
{
var token = Disposables.Call(Release, LockState.Write);
if (CurrentState == LockState.None)
{
// only if there are no locks at the moment
_currentTokens.Add(token);
return(token.ToTask <IDisposable>());
}
else
{
var drt = token.ToDeferredTask <IDisposable>();
_writerQueue.Enqueue(drt);
return(drt.Task);
}
}
}
public Task <IDisposable> ReaderLock()
{
lock (_mutex)
{
var token = Disposables.Call(Release, LockState.Read);
if (CurrentState < LockState.Write)
{
// read or none
_currentTokens.Add(token);
return(token.ToTask <IDisposable>());
}
else
{
var drt = token.ToDeferredTask <IDisposable>();
_readerQueue.Enqueue(drt);
return(drt.Task);
}
}
}
