/// <summary>
/// Chain a sequence of operations using promises.
/// Takes a collection of functions each of which starts an async operation and yields a promise.
/// </summary>
public static IPromise Sequence(IEnumerable <Func <IPromise> > fns)
{
var promise = new Promise();
int count = 0;
fns.Aggregate(
Resolved(),
(prevPromise, fn) => {
int itemSequence = count;
++count;
return(prevPromise
.Then(() => {
var sliceLength = 1f / count;
promise.ReportProgress(sliceLength * itemSequence);
return fn();
})
.Progress(v => {
var sliceLength = 1f / count;
promise.ReportProgress(sliceLength * (v + itemSequence));
})
);
}
)
.Then(() => promise.Resolve())
.Catch(promise.Reject);
return(promise);
}
/// <summary>
/// Handle errors for the promise.
/// </summary>
public IPromise Catch(Action <Exception> onRejected)
{
// Argument.NotNull(() => onRejected);
var resultPromise = new Promise();
resultPromise.WithName(Name);
Action resolveHandler = () => resultPromise.Resolve();
Action <Exception> rejectHandler = ex => {
try {
onRejected(ex);
resultPromise.Resolve();
}
catch (Exception callbackException) {
resultPromise.Reject(callbackException);
}
};
ActionHandlers(resultPromise, resolveHandler, rejectHandler);
ProgressHandlers(resultPromise, v => resultPromise.ReportProgress(v));
return(resultPromise);
}
/// <summary>
/// Add a resolved callback, a rejected callback and a progress callback.
/// The resolved callback chains a value promise (optionally converting to a different value type).
/// </summary>
public IPromise <ConvertedT> Then <ConvertedT>(
Func <PromisedT, IPromise <ConvertedT> > onResolved,
Func <Exception, IPromise <ConvertedT> > onRejected,
Action <float> onProgress
)
{
// This version of the function must supply an onResolved.
// Otherwise there is now way to get the converted value to pass to the resulting promise.
// Argument.NotNull(() => onResolved);
var resultPromise = new Promise <ConvertedT>();
resultPromise.WithName(Name);
Action <PromisedT> resolveHandler = v => {
onResolved(v)
.Progress(progress => resultPromise.ReportProgress(progress))
.Then(
// Should not be necessary to specify the arg type on the next line, but Unity (mono) has an internal compiler error otherwise.
chainedValue => resultPromise.Resolve(chainedValue),
ex => resultPromise.Reject(ex)
);
};
Action <Exception> rejectHandler = ex => {
if (onRejected == null)
{
resultPromise.Reject(ex);
return;
}
try {
onRejected(ex)
.Then(
chainedValue => resultPromise.Resolve(chainedValue),
callbackEx => resultPromise.Reject(callbackEx)
);
}
catch (Exception callbackEx) {
resultPromise.Reject(callbackEx);
}
};
ActionHandlers(resultPromise, resolveHandler, rejectHandler);
if (onProgress != null)
{
ProgressHandlers(this, onProgress);
}
return(resultPromise);
}
/// <summary>
/// Returns a promise that resolves when all of the promises in the enumerable argument have resolved.
/// Returns a promise of a collection of the resolved results.
/// </summary>
public static IPromise <IEnumerable <PromisedT> > All(IEnumerable <IPromise <PromisedT> > promises)
{
var promisesArray = promises.ToArray();
if (promisesArray.Length == 0)
{
return(Promise <IEnumerable <PromisedT> > .Resolved(Enumerable.Empty <PromisedT>()));
}
var remainingCount = promisesArray.Length;
var results = new PromisedT[remainingCount];
var progress = new float[remainingCount];
var resultPromise = new Promise <IEnumerable <PromisedT> >();
resultPromise.WithName("All");
promisesArray.Each((promise, index) => {
promise
.Progress(v => {
progress[index] = v;
if (resultPromise.CurState == PromiseState.Pending)
{
resultPromise.ReportProgress(progress.Average());
}
})
.Then(result => {
progress[index] = 1f;
results[index] = result;
--remainingCount;
if (remainingCount <= 0 && resultPromise.CurState == PromiseState.Pending)
{
// This will never happen if any of the promises errorred.
resultPromise.Resolve(results);
}
})
.Catch(ex => {
if (resultPromise.CurState == PromiseState.Pending)
{
// If a promise errorred and the result promise is still pending, reject it.
resultPromise.Reject(ex);
}
})
.Done();
});
return(resultPromise);
}
/// <summary>
/// Returns a promise that resolves when the first of the promises in the enumerable argument have resolved.
/// Returns the value from the first promise that has resolved.
/// </summary>
public static IPromise <PromisedT> Race(IEnumerable <IPromise <PromisedT> > promises)
{
var promisesArray = promises.ToArray();
if (promisesArray.Length == 0)
{
throw new InvalidOperationException(
"At least 1 input promise must be provided for Race"
);
}
var resultPromise = new Promise <PromisedT>();
resultPromise.WithName("Race");
var progress = new float[promisesArray.Length];
promisesArray.Each((promise, index) => {
promise
.Progress(v => {
if (resultPromise.CurState == PromiseState.Pending)
{
progress[index] = v;
resultPromise.ReportProgress(progress.Max());
}
})
.Then(result => {
if (resultPromise.CurState == PromiseState.Pending)
{
resultPromise.Resolve(result);
}
})
.Catch(ex => {
if (resultPromise.CurState == PromiseState.Pending)
{
// If a promise errorred and the result promise is still pending, reject it.
resultPromise.Reject(ex);
}
})
.Done();
});
return(resultPromise);
}
/// <summary>
/// Add a resolved callback, a rejected callback and a progress callback.
/// The resolved callback chains a non-value promise.
/// </summary>
public IPromise Then(Func <IPromise> onResolved, Action <Exception> onRejected, Action <float> onProgress)
{
var resultPromise = new Promise();
resultPromise.WithName(Name);
Action resolveHandler = () => {
if (onResolved != null)
{
onResolved()
.Progress(progress => resultPromise.ReportProgress(progress))
.Then(
() => resultPromise.Resolve(),
ex => resultPromise.Reject(ex)
);
}
else
{
resultPromise.Resolve();
}
};
Action <Exception> rejectHandler = ex => {
if (onRejected != null)
{
onRejected(ex);
}
resultPromise.Reject(ex);
};
ActionHandlers(resultPromise, resolveHandler, rejectHandler);
if (onProgress != null)
{
ProgressHandlers(this, onProgress);
}
return(resultPromise);
}
/// <summary>
/// Handle errors for the promise.
/// </summary>
public IPromise <PromisedT> Catch(Func <Exception, PromisedT> onRejected)
{
var resultPromise = new Promise <PromisedT>();
resultPromise.WithName(Name);
Action <PromisedT> resolveHandler = v => resultPromise.Resolve(v);
Action <Exception> rejectHandler = ex => {
try {
resultPromise.Resolve(onRejected(ex));
}
catch (Exception cbEx) {
resultPromise.Reject(cbEx);
}
};
ActionHandlers(resultPromise, resolveHandler, rejectHandler);
ProgressHandlers(resultPromise, v => resultPromise.ReportProgress(v));
return(resultPromise);
}
