internal AsyncOperationContext(TaskOperation op, TWork work, TExecutor executor, Task predecessor,
OperationExecutionOptions options, CancellationToken cancellationToken)
: base(op, work, predecessor, options, cancellationToken)
{
this.Executor = executor;
this.ExecutorSource = new TaskCompletionSource <TExecutor>(this.ResultSource);
}
/// <summary>
/// Runs the specified test method.
/// </summary>
internal void RunTest(Delegate testMethod, string testName)
{
testName = string.IsNullOrEmpty(testName) ? string.Empty : $" '{testName}'";
this.Logger.WriteLine($"<TestLog> Running test{testName}.");
this.Assert(testMethod != null, "Unable to execute a null test method.");
this.Assert(Task.CurrentId != null, "The test must execute inside a controlled task.");
ulong operationId = this.GetNextOperationId();
var op = new TaskOperation(operationId, this.Scheduler);
this.Scheduler.RegisterOperation(op);
op.OnEnabled();
Task task = new Task(async() =>
{
try
{
// Update the current asynchronous control flow with the current runtime instance,
// allowing future retrieval in the same asynchronous call stack.
AssignAsyncControlFlowRuntime(this);
OperationScheduler.StartOperation(op);
if (testMethod is Action <IActorRuntime> actionWithRuntime)
{
actionWithRuntime(this);
}
else if (testMethod is Action action)
{
action();
}
else if (testMethod is Func <IActorRuntime, CoyoteTasks.Task> functionWithRuntime)
{
await functionWithRuntime(this);
}
else if (testMethod is Func <CoyoteTasks.Task> function)
{
await function();
}
else
{
throw new InvalidOperationException($"Unsupported test delegate of type '{testMethod.GetType()}'.");
}
IO.Debug.WriteLine("<ScheduleDebug> Completed operation {0} on task '{1}'.", op.Name, Task.CurrentId);
op.OnCompleted();
// Task has completed, schedule the next enabled operation.
this.Scheduler.ScheduleNextEnabledOperation();
}
catch (Exception ex)
{
this.ProcessUnhandledExceptionInOperation(op, ex);
}
});
this.Scheduler.ScheduleOperation(op, task.Id);
task.Start();
this.Scheduler.WaitOperationStart(op);
}
/// <summary>
/// Schedules the specified task operation for execution.
/// </summary>
private void ScheduleTaskOperation(TaskOperation op, Task task)
{
IO.Debug.WriteLine("<CreateLog> Operation '{0}' was created to execute task '{1}'.", op.Name, task.Id);
task.Start();
this.Scheduler.WaitOperationStart(op);
this.Scheduler.ScheduleNextOperation();
}
/// <summary>
/// Creates a new task operation.
/// </summary>
internal TaskOperation CreateTaskOperation()
{
ulong operationId = this.GetNextOperationId();
var op = new TaskOperation(operationId, this.Scheduler);
this.Scheduler.RegisterOperation(op);
return(op);
}
public CoyoteTasks.Task ScheduleAction(Action action, Task predecessor, CancellationToken cancellationToken)
{
// TODO: support cancellations during testing.
this.Assert(action != null, "The task cannot execute a null action.");
ulong operationId = this.Runtime.GetNextOperationId();
var op = new TaskOperation(operationId, this.Scheduler);
this.Scheduler.RegisterOperation(op);
op.OnEnabled();
var task = new Task(() =>
{
try
{
// Update the current asynchronous control flow with the current runtime instance,
// allowing future retrieval in the same asynchronous call stack.
CoyoteRuntime.AssignAsyncControlFlowRuntime(this.Runtime);
OperationScheduler.StartOperation(op);
if (predecessor != null)
{
op.OnWaitTask(predecessor);
}
action();
}
catch (Exception ex)
{
// Report the unhandled exception unless it is our ExecutionCanceledException which is our
// way of terminating async task operations at the end of the test iteration.
if (!(ex is ExecutionCanceledException))
{
this.ReportUnhandledExceptionInOperation(op, ex);
}
// and rethrow it
throw;
}
finally
{
IO.Debug.WriteLine("<ScheduleDebug> Completed operation '{0}' on task '{1}'.", op.Name, Task.CurrentId);
op.OnCompleted();
}
});
// Schedule a task continuation that will schedule the next enabled operation upon completion.
task.ContinueWith(t => this.Scheduler.ScheduleNextEnabledOperation(), TaskScheduler.Current);
IO.Debug.WriteLine("<CreateLog> Operation '{0}' was created to execute task '{1}'.", op.Name, task.Id);
this.Scheduler.ScheduleOperation(op, task.Id);
task.Start();
this.Scheduler.WaitOperationStart(op);
this.Scheduler.ScheduleNextEnabledOperation();
return(new CoyoteTasks.Task(this, task));
}
public CoyoteTasks.Task <TResult> ScheduleFunction <TResult>(Func <CoyoteTasks.Task <TResult> > function, Task predecessor,
CancellationToken cancellationToken)
{
// TODO: support cancellations during testing.
this.Assert(function != null, "The task cannot execute a null function.");
ulong operationId = this.Runtime.GetNextOperationId();
var op = new TaskOperation(operationId, this.Scheduler);
this.Scheduler.RegisterOperation(op);
op.OnEnabled();
var task = new Task <Task <TResult> >(() =>
{
try
{
// Update the current asynchronous control flow with the current runtime instance,
// allowing future retrieval in the same asynchronous call stack.
CoyoteRuntime.AssignAsyncControlFlowRuntime(this.Runtime);
OperationScheduler.StartOperation(op);
if (predecessor != null)
{
op.OnWaitTask(predecessor);
}
CoyoteTasks.Task <TResult> resultTask = function();
this.OnWaitTask(operationId, resultTask.UncontrolledTask);
return(resultTask.UncontrolledTask);
}
catch (Exception ex)
{
// Report the unhandled exception and rethrow it.
this.ReportUnhandledExceptionInOperation(op, ex);
throw;
}
finally
{
IO.Debug.WriteLine("<ScheduleDebug> Completed operation '{0}' on task '{1}'.", op.Name, Task.CurrentId);
op.OnCompleted();
}
});
Task <TResult> innerTask = task.Unwrap();
// Schedule a task continuation that will schedule the next enabled operation upon completion.
innerTask.ContinueWith(t => this.Scheduler.ScheduleNextEnabledOperation(), TaskScheduler.Current);
IO.Debug.WriteLine("<CreateLog> Operation '{0}' was created to execute task '{1}'.", op.Name, task.Id);
this.Scheduler.ScheduleOperation(op, task.Id);
task.Start();
this.Scheduler.WaitOperationStart(op);
this.Scheduler.ScheduleNextEnabledOperation();
return(new CoyoteTasks.Task <TResult>(this, innerTask));
}
internal OperationContext(TaskOperation op, TWork work, Task predecessor, OperationExecutionOptions options,
CancellationToken cancellationToken)
{
this.Operation = op;
this.Work = work ?? throw new ArgumentNullException(nameof(work));
this.Predecessor = predecessor;
this.ResultSource = new TaskCompletionSource <TResult>();
this.Options = options;
this.CancellationToken = cancellationToken;
}
internal Task ScheduleAction(Action action, Task predecessor, bool isYield, bool failException, CancellationToken cancellationToken)
{
cancellationToken.ThrowIfCancellationRequested();
TaskOperation op = this.Runtime.CreateTaskOperation();
OperationExecutionOptions options = OperationContext.CreateOperationExecutionOptions(failException, isYield);
var context = new OperationContext <Action, object>(op, action, predecessor, options, cancellationToken);
var task = new Task(this.ExecuteOperation, context, cancellationToken);
this.ScheduleTaskOperation(op, task);
return(context.ResultSource.Task);
}
internal Task <TResult> ScheduleFunction <TResult>(Func <TResult> function, Task predecessor, CancellationToken cancellationToken)
{
cancellationToken.ThrowIfCancellationRequested();
TaskOperation op = this.Runtime.CreateTaskOperation();
var context = new OperationContext <Func <TResult>, TResult>(op, function, predecessor,
OperationExecutionOptions.None, cancellationToken);
var task = new Task <TResult>(this.ExecuteOperation <Func <TResult>, TResult, TResult>, context, cancellationToken);
this.ScheduleTaskOperation(op, task);
return(context.ResultSource.Task);
}
internal Task <Task> ScheduleFunction(Func <Task> function, Task predecessor, CancellationToken cancellationToken)
{
cancellationToken.ThrowIfCancellationRequested();
Task <Task> task = null;
TaskOperation op = this.Runtime.CreateTaskOperation();
var context = new AsyncOperationContext <Func <Task>, Task, Task>(op, function, task, predecessor,
OperationExecutionOptions.None, cancellationToken);
task = new Task <Task>(this.ExecuteOperation <Func <Task>, Task, Task>, context, cancellationToken);
this.ScheduleTaskOperation(op, task);
return(context.ExecutorSource.Task);
}
public CoyoteTasks.Task <TResult> ScheduleDelegate <TResult>(Delegate work, Task predecessor, CancellationToken cancellationToken)
{
// TODO: support cancellations during testing.
this.Assert(work != null, "The task cannot execute a null delegate.");
ulong operationId = this.Runtime.GetNextOperationId();
var op = new TaskOperation(operationId, this.Scheduler);
this.Scheduler.RegisterOperation(op);
op.OnEnabled();
var task = new Task <TResult>(() =>
{
try
{
// Update the current asynchronous control flow with the current runtime instance,
// allowing future retrieval in the same asynchronous call stack.
CoyoteRuntime.AssignAsyncControlFlowRuntime(this.Runtime);
OperationScheduler.StartOperation(op);
if (predecessor != null)
{
op.OnWaitTask(predecessor);
}
if (work is Func <Task> funcWithTaskResult)
{
Task resultTask = funcWithTaskResult();
this.OnWaitTask(operationId, resultTask);
if (resultTask is TResult typedResultTask)
{
return(typedResultTask);
}
}
else if (work is Func <Task <TResult> > funcWithGenericTaskResult)
{
Task <TResult> resultTask = funcWithGenericTaskResult();
this.OnWaitTask(operationId, resultTask);
return(resultTask.Result);
}
else if (work is Func <TResult> funcWithGenericResult)
{
return(funcWithGenericResult());
}
return(default);
/// <summary>
/// Execute the (asynchronous) operation with the specified context.
/// </summary>
private TResult ExecuteOperation <TWork, TExecutor, TResult>(object state)
{
// Extract the expected operation context from the task state.
var context = state as AsyncOperationContext <TWork, TExecutor, TResult> ?? state as OperationContext <TWork, TResult>;
TaskOperation op = context.Operation;
CancellationToken ct = context.CancellationToken;
TResult result = default;
Exception exception = null;
// The operation execution logic uses two task completion sources: (1) an executor TCS and (2) a result TCS.
// We do this to model the execution of tasks in the .NET runtime. For example, the `Task.Factory.StartNew`
// method has different semantics from `Task.Run`, e.g. the returned task from `Task.Factory.StartNew(Func<T>)`
// completes at the start of an asynchronous operation, so someone cannot await on it for the completion of
// the operation. Instead, someone needs to first use `task.Unwrap()`, and then await on the unwrapped task.
// To model this, the executor TCS completes at the start of the operation, and contains in its `task.AsyncState`
// a reference to the result TCS. This approach allows us to implement `task.Unwrap` in a way that gives access
// to the result TCS, which someone can then await for the asynchronous completion of the operation.
try
{
// Update the current asynchronous control flow with the current runtime instance,
// allowing future retrieval in the same asynchronous call stack.
CoyoteRuntime.AssignAsyncControlFlowRuntime(this.Runtime);
// Notify the scheduler that the operation started. This will yield execution until
// the operation is ready to get scheduled.
this.Scheduler.StartOperation(op);
if (context is AsyncOperationContext <TWork, TExecutor, TResult> asyncContext)
{
// If the operation is asynchronous, then set the executor task completion source, which
// can be used by `UnwrapTask` to unwrap and return the task executing this operation.
this.SetTaskCompletionSource(asyncContext.ExecutorSource, asyncContext.Executor, null, ct);
}
if (context.Predecessor != null)
{
// If there is a predecessor task, then wait until the predecessor completes.
ct.ThrowIfCancellationRequested();
op.OnWaitTask(context.Predecessor);
}
// Check if the operation must be canceled before starting the work.
ct.ThrowIfCancellationRequested();
// Start executing the (asynchronous) work.
Task executor = null;
if (context.Work is Func <Task <TResult> > funcWithTaskResult)
{
executor = funcWithTaskResult();
}
else if (context.Work is Func <Task> funcWithTask)
{
executor = funcWithTask();
}
else if (context.Work is Func <CoyoteTasks.Task <TResult> > funcWithCoyoteTaskResult)
{
// TODO: temporary until we remove the custom task type.
executor = funcWithCoyoteTaskResult().UncontrolledTask;
}
else if (context.Work is Func <CoyoteTasks.Task> funcWithCoyoteTask)
{
// TODO: temporary until we remove the custom task type.
executor = funcWithCoyoteTask().UncontrolledTask;
}
else if (context.Work is Func <TResult> func)
{
result = func();
}
else
{
throw new NotSupportedException($"Unable to execute work with unsupported type {context.Work.GetType()}.");
}
if (executor != null)
{
// If the work is asynchronous, then wait until it completes.
this.OnWaitTask(op.Id, executor);
if (executor.IsFaulted)
{
// Propagate the failing exception by rethrowing it.
ExceptionDispatchInfo.Capture(executor.Exception).Throw();
}
else if (executor.IsCanceled)
{
if (op.Exception != null)
{
// An exception has been already captured, so propagate it.
ExceptionDispatchInfo.Capture(op.Exception).Throw();
}
else
{
// Wait the canceled executor (which is non-blocking as it has already completed)
// to throw the generated `OperationCanceledException`.
executor.Wait();
}
}
// Safely get the result without blocking as the work has completed.
result = executor is Task <TResult> resultTask ? resultTask.Result :
executor is TResult r ? r : default;
}
}
catch (Exception ex)
{
// Unwrap and cache the exception to propagate it.
exception = ControlledRuntime.UnwrapException(ex);
this.ReportThrownException(exception);
}
finally
{
IO.Debug.WriteLine("<ScheduleDebug> Completed operation '{0}' on task '{1}'.", op.Name, Task.CurrentId);
op.OnCompleted();
// Set the result task completion source to notify to the awaiters that the operation
// has been completed, and schedule the next enabled operation.
this.SetTaskCompletionSource(context.ResultSource, result, exception, default);
this.Scheduler.ScheduleNextOperation();
}
return(result);
}
/// <summary>
/// Execute the operation with the specified context.
/// </summary>
private void ExecuteOperation(object state)
{
// Extract the expected operation context from the task state.
var context = state as OperationContext <Action, object>;
TaskOperation op = context.Operation;
CancellationToken ct = context.CancellationToken;
Exception exception = null;
try
{
// Update the current asynchronous control flow with the current runtime instance,
// allowing future retrieval in the same asynchronous call stack.
CoyoteRuntime.AssignAsyncControlFlowRuntime(this.Runtime);
// Notify the scheduler that the operation started. This will yield execution until
// the operation is ready to get scheduled.
this.Scheduler.StartOperation(op);
if (context.Predecessor != null)
{
// If there is a predecessor task, then wait until the predecessor completes.
ct.ThrowIfCancellationRequested();
op.OnWaitTask(context.Predecessor);
}
if (context.Options.HasFlag(OperationExecutionOptions.YieldAtStart))
{
// Try yield execution to the next operation.
this.Scheduler.ScheduleNextOperation(true);
}
// Check if the operation must be canceled before starting the work.
ct.ThrowIfCancellationRequested();
// Start executing the work.
context.Work();
}
catch (Exception ex)
{
if (context.Options.HasFlag(OperationExecutionOptions.FailOnException))
{
this.Assert(false, "Unhandled exception. {0}", ex);
}
else
{
// Unwrap and cache the exception to propagate it.
exception = ControlledRuntime.UnwrapException(ex);
this.ReportThrownException(exception);
}
}
finally
{
IO.Debug.WriteLine("<ScheduleDebug> Completed operation '{0}' on task '{1}'.", op.Name, Task.CurrentId);
op.OnCompleted();
// Set the result task completion source to notify to the awaiters that the operation
// has been completed, and schedule the next enabled operation.
this.SetTaskCompletionSource(context.ResultSource, null, exception, default);
this.Scheduler.ScheduleNextOperation();
}
}
public CoyoteTasks.Task<TResult> ScheduleDelegate<TResult>(Delegate work, Task predecessor, CancellationToken cancellationToken)
{
// TODO: support cancellations during testing.
this.Assert(work != null, "The task cannot execute a null delegate.");
ulong operationId = this.Runtime.GetNextOperationId();
var op = new TaskOperation(operationId, this.Scheduler);
this.Scheduler.RegisterOperation(op);
op.OnEnabled();
var task = new Task<TResult>(() =>
{
try
{
// Update the current asynchronous control flow with the current runtime instance,
// allowing future retrieval in the same asynchronous call stack.
CoyoteRuntime.AssignAsyncControlFlowRuntime(this.Runtime);
OperationScheduler.StartOperation(op);
if (predecessor != null)
{
op.OnWaitTask(predecessor);
}
if (work is Func<Task> funcWithTaskResult)
{
Task resultTask = funcWithTaskResult();
this.OnWaitTask(operationId, resultTask);
if (resultTask is TResult typedResultTask)
{
return typedResultTask;
}
}
else if (work is Func<Task<TResult>> funcWithGenericTaskResult)
{
Task<TResult> resultTask = funcWithGenericTaskResult();
this.OnWaitTask(operationId, resultTask);
return resultTask.Result;
}
else if (work is Func<TResult> funcWithGenericResult)
{
return funcWithGenericResult();
}
return default;
}
catch (Exception ex)
{
// Report the unhandled exception and rethrow it.
ReportUnhandledExceptionInOperation(op, ex);
throw;
}
finally
{
IO.Debug.WriteLine("<ScheduleDebug> Completed operation '{0}' on task '{1}'.", op.Name, Task.CurrentId);
op.OnCompleted();
}
}, cancellationToken);
// Schedule a task continuation that will schedule the next enabled operation upon completion.
task.ContinueWith(t => this.Scheduler.ScheduleNextEnabledOperation(), TaskScheduler.Current);
IO.Debug.WriteLine("<CreateLog> Operation '{0}' was created to execute task '{1}'.", op.Name, task.Id);
this.Scheduler.ScheduleOperation(op, task.Id);
task.Start();
this.Scheduler.WaitOperationStart(op);
this.Scheduler.ScheduleNextEnabledOperation();
return new CoyoteTasks.Task<TResult>(this, task);
}
internal void RunTest(Delegate testMethod, string testName)
{
testName = string.IsNullOrEmpty(testName) ? string.Empty : $" '{testName}'";
this.Logger.WriteLine($"<TestLog> Running test{testName}.");
this.Assert(testMethod != null, "Unable to execute a null test method.");
this.Assert(Task.CurrentId != null, "The test must execute inside a controlled task.");
TaskOperation op = this.CreateTaskOperation();
Task task = new Task(() =>
{
try
{
// Update the current asynchronous control flow with the current runtime instance,
// allowing future retrieval in the same asynchronous call stack.
AssignAsyncControlFlowRuntime(this);
this.Scheduler.StartOperation(op);
Task testMethodTask = null;
if (testMethod is Action <IActorRuntime> actionWithRuntime)
{
actionWithRuntime(this);
}
else if (testMethod is Action action)
{
action();
}
else if (testMethod is Func <IActorRuntime, Task> functionWithRuntime)
{
testMethodTask = functionWithRuntime(this);
}
else if (testMethod is Func <Task> function)
{
testMethodTask = function();
}
else if (testMethod is Func <IActorRuntime, CoyoteTasks.Task> functionWithRuntime2)
{
testMethodTask = functionWithRuntime2(this).UncontrolledTask;
}
else if (testMethod is Func <CoyoteTasks.Task> function2)
{
testMethodTask = function2().UncontrolledTask;
}
else
{
throw new InvalidOperationException($"Unsupported test delegate of type '{testMethod.GetType()}'.");
}
if (testMethodTask != null)
{
// The test method is asynchronous, so wait on the task to complete.
op.OnWaitTask(testMethodTask);
if (testMethodTask.Exception != null)
{
// The test method failed with an unhandled exception.
ExceptionDispatchInfo.Capture(testMethodTask.Exception).Throw();
}
else if (testMethodTask.IsCanceled)
{
throw new TaskCanceledException(testMethodTask);
}
}
IO.Debug.WriteLine("<ScheduleDebug> Completed operation {0} on task '{1}'.", op.Name, Task.CurrentId);
op.OnCompleted();
// Task has completed, schedule the next enabled operation, which terminates exploration.
this.Scheduler.ScheduleNextOperation();
}
catch (Exception ex)
{
this.ProcessUnhandledExceptionInOperation(op, ex);
}
});
task.Start();
this.Scheduler.WaitOperationStart(op);
}