public void canceled_transition_reverts_back_to_original_state()
{
var factory = new StateMachineTaskFactory <State>();
var cancellationTokenSource = new CancellationTokenSource();
factory.RegisterTransition(State.Starting, State.Started, (ct, o) => TaskUtil.FromResult(true));
factory.RegisterTransition(State.Stopping, State.Stopped, (ct, o) => TaskUtil.Delay(TimeSpan.FromSeconds(3), cancellationTokenSource.Token));
factory.StateChanged += (s, e) =>
{
if (e.NewState == State.Stopping)
{
// cancel the stop
cancellationTokenSource.Cancel();
}
};
var startedTask = factory.TransitionTo(State.Started);
var stoppedTask = factory.TransitionTo(State.Stopped, cancellationTokenSource.Token);
startedTask.Wait(TimeSpan.FromSeconds(3));
try
{
stoppedTask.Wait(TimeSpan.FromSeconds(3));
Assert.True(false, "Failed to throw exception.");
}
catch (AggregateException ex)
{
Assert.Equal(1, ex.InnerExceptions.Count);
Assert.IsType <OperationCanceledException>(ex.InnerExceptions[0]);
Assert.Equal(State.Started, factory.State);
}
}
public void state_change_is_raised_as_state_changes()
{
var factory = new StateMachineTaskFactory <State>(State.Stopped);
factory.RegisterTransition(State.Starting, State.Started, (ct, o) => TaskUtil.FromResult(true));
factory.RegisterTransition(State.Stopping, State.Stopped, (ct, o) => TaskUtil.FromResult(true));
var stateChanges = new List <StateChangedEventArgs <State> >();
factory.StateChanged += (s, e) => stateChanges.Add(e);
factory.TransitionTo(State.Started).Wait(TimeSpan.FromSeconds(1));
factory.TransitionTo(State.Stopped).Wait(TimeSpan.FromSeconds(1));
factory.TransitionTo(State.Started).Wait(TimeSpan.FromSeconds(1));
factory.TransitionTo(State.Stopped).Wait(TimeSpan.FromSeconds(1));
Assert.Equal(8, stateChanges.Count);
Assert.Equal(State.Stopped, stateChanges[0].OldState);
Assert.Equal(State.Starting, stateChanges[0].NewState);
Assert.Equal(State.Starting, stateChanges[1].OldState);
Assert.Equal(State.Started, stateChanges[1].NewState);
Assert.Equal(State.Started, stateChanges[2].OldState);
Assert.Equal(State.Stopping, stateChanges[2].NewState);
Assert.Equal(State.Stopping, stateChanges[3].OldState);
Assert.Equal(State.Stopped, stateChanges[3].NewState);
Assert.Equal(State.Stopped, stateChanges[4].OldState);
Assert.Equal(State.Starting, stateChanges[4].NewState);
Assert.Equal(State.Starting, stateChanges[5].OldState);
Assert.Equal(State.Started, stateChanges[5].NewState);
Assert.Equal(State.Started, stateChanges[6].OldState);
Assert.Equal(State.Stopping, stateChanges[6].NewState);
Assert.Equal(State.Stopping, stateChanges[7].OldState);
Assert.Equal(State.Stopped, stateChanges[7].NewState);
}
public void transition_to_returns_completed_task_if_already_in_desired_state()
{
var factory = new StateMachineTaskFactory <State>();
factory.RegisterTransition(State.Starting, State.Started, (ct, o) => TaskUtil.FromResult(true));
factory.TransitionTo(State.Started).Wait();
Assert.Equal(TaskStatus.RanToCompletion, factory.TransitionTo(State.Started).Status);
}
public void register_transition_throws_if_transition_already_registered()
{
var factory = new StateMachineTaskFactory <State>();
factory.RegisterTransition(State.Starting, State.Started, (ct, o) => TaskUtil.FromResult(true));
var ex = Assert.Throws <InvalidOperationException>(() => factory.RegisterTransition(State.Starting, State.Started, (ct, o) => TaskUtil.FromResult(true)));
Assert.Equal("A transition to state 'Started' has already been registered.", ex.Message);
}
/// <summary>
/// Writes the string to the response body.
/// </summary>
/// <param name="content">The content.</param>
/// <param name="cancellationToken">The cancellation token.</param>
/// <returns></returns>
public Task WriteAsync(string content, CancellationToken cancellationToken)
{
if (content == null)
{
return(TaskUtil.FromResult(0));
}
var buff = Encoding.UTF8.GetBytes(content);
return(Body.WriteAsync(buff, 0, buff.Length, cancellationToken));
}
/// <summary>
/// Asynchronously closes the specified screen.
/// </summary>
/// <param name="screen">The <see cref="UIScreen"/> to close.</param>
/// <param name="duration">The amount of time over which to transition the screen's state, or
/// <see langword="null"/> to use the default transition time.</param>
/// <returns>A task which represents the asynchronous operation.</returns>
public Task CloseAsync(UIScreen screen, TimeSpan?duration = null)
{
Contract.Require(screen, nameof(screen));
if (screens.Contains(screen))
{
return(screen.CloseAsync(duration));
}
return(TaskUtil.FromResult(false));
}
public void transition_to_passes_any_state_to_task_creation_function()
{
var factory = new StateMachineTaskFactory <State>();
string receivedState = null;
factory.RegisterTransition(
State.Starting,
State.Started,
(ct, o) =>
{
receivedState = o as string;
return(TaskUtil.FromResult(true));
});
factory.TransitionTo(State.Started, CancellationToken.None, null, "here is the state").Wait();
Assert.Equal("here is the state", receivedState);
}
/// <summary>
/// Asynchronously closes all open screens except for the specified screen.
/// </summary>
/// <param name="except">The screen which should remain open when all other screens are closed.</param>
/// <param name="duration">The amount of time over which to transition the screens' states, or
/// <see langword="null"/> to use the default transition time.</param>
/// <returns>A collection of <see cref="Task"/> objects representing the asynchronous operations.</returns>
public Task CloseAllExceptAsync(UIScreen except, TimeSpan?duration = null)
{
var tasks = default(List <Task>);
for (var current = screens.First; current != null; current = current.Next)
{
var screen = current.Value;
if (screen != except)
{
tasks = tasks ?? new List <Task>();
tasks.Add(screen.CloseAsync(duration));
}
}
return(tasks.Count == 0 ? TaskUtil.FromResult(true) :
new Task(() => Task.WaitAll(tasks.ToArray())));
}
/// <summary>
/// Asynchronously closes any screens which match the specified predicate.
/// </summary>
/// <param name="predicate">The predicate with which to determine which screens to close.</param>
/// <param name="duration">The amount of time over which to transition the screens' states, or
/// <see langword="null"/> to use the default transition time.</param>
/// <returns>A collection of <see cref="Task"/> objects representing the asynchronous operations.</returns>
public Task CloseMatchingAsync(Func <UIScreen, Boolean> predicate, TimeSpan?duration = null)
{
Contract.Require(predicate, nameof(predicate));
var tasks = default(List <Task>);
for (var current = screens.First; current != null; current = current.Next)
{
var screen = current.Value;
if (predicate(screen))
{
tasks = tasks ?? new List <Task>();
tasks.Add(screen.CloseAsync(duration));
}
}
return(tasks.Count == 0 ? TaskUtil.FromResult(true) :
new Task(() => Task.WaitAll(tasks.ToArray())));
}
public void transition_to_can_be_canceled_before_transition_takes_place()
{
var factory = new StateMachineTaskFactory <State>();
var cancellationTokenSource = new CancellationTokenSource();
factory.RegisterTransition(State.Starting, State.Started, (ct, o) => TaskUtil.FromResult(true));
cancellationTokenSource.Cancel();
var startedTask = factory.TransitionTo(State.Started, cancellationTokenSource.Token);
try
{
startedTask.Wait();
Assert.True(false, "Failed to throw exception.");
}
catch (AggregateException ex)
{
Assert.Equal(1, ex.InnerExceptions.Count);
Assert.IsType <OperationCanceledException>(ex.InnerExceptions[0]);
}
}
public void failed_transition_reverts_back_to_original_state()
{
var factory = new StateMachineTaskFactory <State>();
factory.RegisterTransition(State.Starting, State.Started, (ct, o) => TaskUtil.FromResult(true));
factory.RegisterTransition(State.Stopping, State.Stopped, (ct, o) => { throw new InvalidOperationException("Something went wrong"); });
var startedTask = factory.TransitionTo(State.Started);
var stoppedTask = factory.TransitionTo(State.Stopped);
startedTask.Wait(TimeSpan.FromSeconds(3));
try
{
stoppedTask.Wait(TimeSpan.FromSeconds(3));
Assert.True(false, "Failed to throw exception.");
}
catch (AggregateException ex)
{
Assert.Equal(1, ex.InnerExceptions.Count);
Assert.IsType <InvalidOperationException>(ex.InnerExceptions[0]);
Assert.Equal(State.Started, factory.State);
}
}
public void transition_to_can_be_forbidden()
{
var factory = new StateMachineTaskFactory <State>();
factory.RegisterTransition(State.Starting, State.Started, (ct, o) => TaskUtil.FromResult(true));
factory.RegisterTransition(State.Stopping, State.Stopped, (ct, o) => TaskUtil.FromResult(true));
var startedTask = factory.TransitionTo(State.Started, CancellationToken.None, x => x == State.Undefined);
var stoppedTask = factory.TransitionTo(State.Stopped, CancellationToken.None, x => x != State.Started);
startedTask.Wait(TimeSpan.FromSeconds(3));
try
{
stoppedTask.Wait(TimeSpan.FromSeconds(3));
Assert.True(false, "Failed to throw exception.");
}
catch (AggregateException ex)
{
Assert.Equal(1, ex.InnerExceptions.Count);
var ex2 = Assert.IsType <StateTransitionForbiddenException <State> >(ex.InnerExceptions[0]);
Assert.Equal(State.Stopped, ex2.TargetState);
Assert.Equal(State.Started, ex2.State);
Assert.Equal("A transition to state 'Stopped' was forbidden by the validate transition callback.", ex2.Message);
}
}
public void transition_to_can_be_canceled()
{
var factory = new StateMachineTaskFactory <State>();
var cancellationTokenSource = new CancellationTokenSource();
factory.RegisterTransition(State.Starting, State.Started, (ct, o) => TaskUtil.FromResult(true));
factory.RegisterTransition(State.Stopping, State.Stopped, (ct, o) => TaskUtil.Delay(TimeSpan.FromMilliseconds(150)));
var startedTask = factory.TransitionTo(State.Started, cancellationTokenSource.Token);
startedTask.ContinueWith(x => cancellationTokenSource.Cancel());
var stoppedTask = factory.TransitionTo(State.Stopped, cancellationTokenSource.Token);
startedTask.Wait(TimeSpan.FromSeconds(3));
try
{
stoppedTask.Wait(TimeSpan.FromSeconds(3));
Assert.True(false, "Failed to throw exception.");
}
catch (AggregateException ex)
{
Assert.Equal(1, ex.InnerExceptions.Count);
Assert.IsType <OperationCanceledException>(ex.InnerExceptions[0]);
}
}
public Task TransitionTo(T endTransitionState, CancellationToken cancellationToken = default(CancellationToken), ValidateTransitionCallback <T> validateTransitionCallback = null, object state = null)
{
lock (this.stateSync)
{
if (EqualityComparer <T> .Default.Equals(this.state, endTransitionState))
{
// already in the requested state - nothing to do
return(TaskUtil.FromResult(true));
}
else if (this.transitionToState.HasValue && EqualityComparer <T> .Default.Equals(this.transitionToState.Value, endTransitionState))
{
// already in the process of transitioning to the requested state - return same transition task
return(this.transitionToTask);
}
else if (this.transitionToTask != null)
{
// not in the requested state, but there is an outstanding transition in progress, so come back to this request once it's done
return(this.transitionToTask.Then(x => this.TransitionTo(endTransitionState, cancellationToken, validateTransitionCallback, state)));
}
else if (validateTransitionCallback != null && !validateTransitionCallback(this.State))
{
// transition is forbidden, so return a failing task to that affect
var taskCompletionSource = new TaskCompletionSource <bool>();
var exception = new StateTransitionForbiddenException <T>(endTransitionState, this.State);
taskCompletionSource.TrySetException(exception);
return(taskCompletionSource.Task);
}
// else, need to transition to the chosen state
TransitionRegistrationInfo transitionRegistrationInfo;
var result = this.transitionRegistrations.TryGetValue(endTransitionState, out transitionRegistrationInfo);
exceptionHelper.ResolveAndThrowIf(!result, "transitionNotRegistered", endTransitionState);
var beginTransitionState = transitionRegistrationInfo.BeginTransitionState;
var task = transitionRegistrationInfo.TaskFactory(cancellationToken, state);
exceptionHelper.ResolveAndThrowIf(task == null, "taskFactoryReturnedNull", endTransitionState);
var previousState = this.State;
this.State = beginTransitionState;
this.transitionToState = endTransitionState;
this.transitionToTask = task
.ContinueWith(
x =>
{
if (x.IsFaulted || cancellationToken.IsCancellationRequested)
{
// faulted or canceled, so roll back to previous state
lock (this.stateSync)
{
this.State = previousState;
this.transitionToState = null;
this.transitionToTask = null;
}
if (x.IsFaulted)
{
throw x.Exception;
}
cancellationToken.ThrowIfCancellationRequested();
}
else
{
// succeeded, so commit to end state
lock (this.stateSync)
{
this.State = endTransitionState;
this.transitionToState = null;
this.transitionToTask = null;
}
}
});
return(this.transitionToTask);
}
}
