##// END OF EJS Templates
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Promise.cs
208 lines | 5.4 KiB | text/x-csharp | CSharpLexer
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Reflection;
using System.Threading.Tasks;
using Implab.Parallels;
namespace Implab {
public class Promise : AbstractEvent<IResolvable>, IPromise {
public static IDispatcher DefaultDispatcher {
get {
return ThreadPoolDispatcher.Instance;
}
}
class ResolvableSignal : IResolvable {
public Signal Signal { get; private set; }
public ResolvableSignal() {
Signal = new Signal();
}
public void Reject(Exception error) {
Signal.Set();
}
public void Resolve() {
Signal.Set();
}
}
PromiseState m_state;
Exception m_error;
public bool IsRejected {
get {
return m_state == PromiseState.Rejected;
}
}
public bool IsFulfilled {
get {
return m_state == PromiseState.Fulfilled;
}
}
public Exception RejectReason {
get {
return m_error;
}
}
internal Promise() {
}
internal void ResolvePromise() {
if (BeginTransit()) {
m_state = PromiseState.Fulfilled;
CompleteTransit();
}
}
internal void RejectPromise(Exception reason) {
if (BeginTransit()) {
m_error = reason;
m_state = PromiseState.Rejected;
CompleteTransit();
}
}
#region implemented abstract members of AbstractPromise
protected override void SignalHandler(IResolvable handler) {
switch (m_state) {
case PromiseState.Fulfilled:
handler.Resolve();
break;
case PromiseState.Rejected:
handler.Reject(RejectReason);
break;
default:
throw new InvalidOperationException(String.Format("Invalid promise signal: {0}", m_state));
}
}
protected void WaitResult(int timeout) {
if (!(IsResolved || GetFulfillSignal().Wait(timeout)))
throw new TimeoutException();
}
protected Signal GetFulfillSignal() {
var next = new ResolvableSignal();
Then(next);
return next.Signal;
}
#endregion
public Type ResultType {
get {
return typeof(void);
}
}
protected void Rethrow() {
Debug.Assert(m_error != null);
if (m_error is OperationCanceledException)
throw new OperationCanceledException("Operation cancelled", m_error);
else
throw new TargetInvocationException(m_error);
}
public void Then(IResolvable next) {
AddHandler(next);
}
public IPromise<T> Cast<T>() {
throw new InvalidCastException();
}
public void Join() {
WaitResult(-1);
if (IsRejected)
Rethrow();
}
public void Join(int timeout) {
WaitResult(timeout);
if (IsRejected)
Rethrow();
}
public static ResolvedPromise Resolve() {
return new ResolvedPromise();
}
public static ResolvedPromise<T> Resolve<T>(T result) {
return new ResolvedPromise<T>(result);
}
public static RejectedPromise Reject(Exception reason) {
return new RejectedPromise(reason);
}
public static RejectedPromise<T> Reject<T>(Exception reason) {
return new RejectedPromise<T>(reason);
}
public static IPromise Create(PromiseExecutor executor) {
Safe.ArgumentNotNull(executor, nameof(executor));
var p = new Promise();
var d = new Deferred(p, DefaultDispatcher);
try {
executor(d);
} catch (Exception e) {
d.Reject(e);
}
return d.Promise;
}
public static IPromise<T> Create<T>(PromiseExecutor<T> executor) {
Safe.ArgumentNotNull(executor, nameof(executor));
var d = new Deferred<T>();
try {
executor(d);
} catch (Exception e) {
d.Reject(e);
}
return d.Promise;
}
public static IPromise All(IEnumerable<IPromise> promises) {
var d = new Deferred();
var all = new PromiseAll(d);
foreach (var promise in promises) {
all.AddPromise(promise);
if (all.Done)
break;
}
all.Complete();
return all.ResultPromise;
}
public static IPromise<T[]> All<T>(IEnumerable<IPromise<T>> promises, Func<T, IPromise> cleanup = null, Action cancel = null) {
var d = new Deferred<T[]>();
var all = new PromiseAll<T>(d, cleanup, cancel);
foreach (var promise in promises) {
all.AddPromise(promise);
if (all.Done)
break;
}
all.Complete();
return all.ResultPromise;
}
}
}