/// <summary>
/// Creates a new Promise instance from a task.
/// </summary>
/// <param name="task"> A task to wait on. </param>
/// <returns> The Promise instance. </returns>
/// <remarks>
/// If the task is of type Task<object> then the result of the task will be used to
/// resolve the promise. Otherwise, the promise is resolved with "undefined" as the value.
/// </remarks>
public PromiseInstance FromTask(Task task)
{
if (task == null)
{
throw new ArgumentNullException(nameof(task));
}
// Create a new promise.
var promise = new PromiseInstance(this.InstancePrototype);
// Execute some code after the task completes.
task.ConfigureAwait(continueOnCapturedContext: false).GetAwaiter().OnCompleted(() =>
{
// Enqueue an event which resolves the promise.
Engine.EnqueueEvent(() =>
{
try
{
if (task is Task <object> objectTask)
{
promise.Resolve(objectTask.Result);
}
else
{
promise.Resolve(Undefined.Value);
}
}
catch (AggregateException ex)
{
if (ex.InnerExceptions.Count == 1)
{
var innerException = ex.InnerExceptions[0];
if (innerException is JavaScriptException innerJSException)
{
promise.Reject(innerJSException.GetErrorObject(Engine));
}
else
{
promise.Reject(innerException.Message);
}
}
else
{
promise.Reject(ex.Message);
}
}
catch (JavaScriptException ex)
{
promise.Reject(ex.GetErrorObject(Engine));
}
catch (Exception ex)
{
promise.Reject(ex.Message);
}
});
});
return(promise);
}
/// <summary>
/// Creates a new Promise instance.
/// </summary>
/// <param name="notify">A <see cref="INotifyCompletion"/> that will signal the success or failure of the promise.</param>
/// <returns>The Promise instance.</returns>
public PromiseInstance Construct <T>(T notify)
where T : INotifyCompletion
{
var promise = new PromiseInstance(this.InstancePrototype);
if (notify == null)
{
return(promise);
}
notify.OnCompleted(() =>
{
try
{
promise.Resolve(TaskAwaiterCache.GetResult(notify));
}
catch (JavaScriptException jex)
{
promise.Reject(jex.ErrorObject);
}
catch (Exception e)
{
promise.Reject(e.Message);
}
});
return(promise);
}
public PromiseInstance Resolve(object result)
{
var promise = new PromiseInstance(this.InstancePrototype);
promise.Resolve(result);
return(promise);
}
public PromiseInstance Resolve(object value)
{
// If the constructor of value === this, then return as is.
if (value is PromiseInstance promise)
{
return(promise);
}
var result = new PromiseInstance(this.InstancePrototype);
result.Resolve(value);
return(result);
}
public PromiseInstance Race(ObjectInstance iterable)
{
if (iterable == null)
{
throw new JavaScriptException(iterable.Engine, ErrorType.TypeError, "The parameter must be an iterable.");
}
var iterator = TypeUtilities.GetIterator(iterable.Engine, iterable);
var promises = TypeUtilities.Iterate(iterator.Engine, iterator);
var promise = new PromiseInstance(iterable.Engine.Promise.InstancePrototype);
foreach (var promiseOrValue in promises)
{
if (promise.State != PromiseState.Pending)
{
break;
}
promise.Resolve(promiseOrValue);
}
return(promise);
}
public PromiseInstance All(ObjectInstance iterable)
{
if (iterable == null)
{
throw new JavaScriptException(iterable.Engine, ErrorType.TypeError, "The parameter must be an iterable.");
}
var iterator = TypeUtilities.GetIterator(iterable.Engine, iterable);
var promises = TypeUtilities.Iterate(iterator.Engine, iterator).ToList();
var results = Engine.Array.Construct(new object[promises.Count]);
var count = promises.Count;
var promise = new PromiseInstance(iterable.Engine.Promise.InstancePrototype);
// The promise is resolved immediately if the iterable is empty.
if (promises.Count == 0)
{
promise.Resolve(results);
return(promise);
}
for (var i = 0; i < promises.Count; i++)
{
if (promise.State != PromiseState.Pending)
{
break;
}
if (promises[i] is PromiseInstance p)
{
if (p.State == PromiseState.Rejected)
{
promise.Reject(p.Result);
break;
}
else if (p.State == PromiseState.Fulfilled)
{
results[i] = p.Result;
if (--count == 0)
{
promise.Resolve(results);
break;
}
continue;
}
var j = i; // Some C# versions need this.
p.Then(new ClrStubFunction(Engine.FunctionInstancePrototype, "", 1, (engine, thisObj, args) =>
{
if (promise.State != PromiseState.Pending)
{
return(Undefined.Value);
}
results[j] = args[0];
if (--count == 0)
{
promise.Resolve(results);
}
return(Undefined.Value);
}),
new ClrStubFunction(Engine.FunctionInstancePrototype, "", 1, (engine, thisObj, args) =>
{
promise.Reject(args[0]);
return(Undefined.Value);
}));
continue;
}
else if (promises[i] is ObjectInstance obj && obj.HasProperty("then"))
{
FunctionInstance then;
try
{
then = obj.GetPropertyValue("then") as FunctionInstance;
}
catch (JavaScriptException jex)
{
promise.Reject(jex.ErrorObject);
break;
}
if (then != null)
{
try
{
var j = i; // Some C# versions need this.
var resolve = new ClrStubFunction(iterable.Engine.Function.InstancePrototype, (engine, ths, arg) =>
{
if (promise.State != PromiseState.Pending)
{
return(Undefined.Value);
}
results[j] = arg.Length == 0
? Undefined.Value
: arg[0];
if (--count == 0)
{
promise.Resolve(results);
}
return(Undefined.Value);
});
then.Call(obj, resolve, promise.RejectFunction);
continue;
}
catch (JavaScriptException jex)
{
promise.Reject(jex.ErrorObject);
break;
}
}
}
results[i] = promises[i];
if (--count == 0)
{
promise.Resolve(results);
break;
}
}
return(promise);
}