mirror of https://github.com/Cysharp/UniTask
1172 lines
52 KiB
Markdown
1172 lines
52 KiB
Markdown
UniTask
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===
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[](https://github.com/Cysharp/UniTask/actions) [](https://github.com/Cysharp/UniTask/releases) [](https://github.com/Cysharp/UniTask/blob/master/README_CN.md)
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Provides an efficient allocation free async/await integration for Unity.
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* Struct based `UniTask<T>` and custom AsyncMethodBuilder to achieve zero allocation
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* Makes all Unity AsyncOperations and Coroutines awaitable
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* PlayerLoop based task(`UniTask.Yield`, `UniTask.Delay`, `UniTask.DelayFrame`, etc..) that enable replacing all coroutine operations
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* MonoBehaviour Message Events and uGUI Events as awaitable/async-enumerable
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* Runs completely on Unity's PlayerLoop so doesn't use threads and runs on WebGL, wasm, etc.
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* Asynchronous LINQ, with Channel and AsyncReactiveProperty
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* TaskTracker window to prevent memory leaks
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* Highly compatible behaviour with Task/ValueTask/IValueTaskSource
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For technical details, see blog post: [UniTask v2 — Zero Allocation async/await for Unity, with Asynchronous LINQ
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](https://medium.com/@neuecc/unitask-v2-zero-allocation-async-await-for-unity-with-asynchronous-linq-1aa9c96aa7dd)
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For advanced tips, see blog post: [Extends UnityWebRequest via async decorator pattern — Advanced Techniques of UniTask](https://medium.com/@neuecc/extends-unitywebrequest-via-async-decorator-pattern-advanced-techniques-of-unitask-ceff9c5ee846)
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<!-- START doctoc generated TOC please keep comment here to allow auto update -->
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<!-- DON'T EDIT THIS SECTION, INSTEAD RE-RUN doctoc TO UPDATE -->
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## Table of Contents
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- [Getting started](#getting-started)
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- [Basics of UniTask and AsyncOperation](#basics-of-unitask-and-asyncoperation)
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- [Cancellation and Exception handling](#cancellation-and-exception-handling)
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- [Timeout handling](#timeout-handling)
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- [Progress](#progress)
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- [PlayerLoop](#playerloop)
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- [async void vs async UniTaskVoid](#async-void-vs-async-unitaskvoid)
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- [UniTaskTracker](#unitasktracker)
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- [External Assets](#external-assets)
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- [AsyncEnumerable and Async LINQ](#asyncenumerable-and-async-linq)
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- [Awaitable Events](#awaitable-events)
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- [Channel](#channel)
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- [vs Awaitable](#vs-awaitable)
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- [For Unit Testing](#for-unit-testing)
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- [ThreadPool limitation](#threadpool-limitation)
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- [IEnumerator.ToUniTask limitation](#ienumeratortounitask-limitation)
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- [For UnityEditor](#for-unityeditor)
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- [Compare with Standard Task API](#compare-with-standard-task-api)
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- [Pooling Configuration](#pooling-configuration)
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- [Allocation on Profiler](#allocation-on-profiler)
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- [UniTaskSynchronizationContext](#unitasksynchronizationcontext)
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- [API References](#api-references)
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- [UPM Package](#upm-package)
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- [Install via git URL](#install-via-git-url)
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- [.NET Core](#net-core)
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- [License](#license)
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<!-- END doctoc generated TOC please keep comment here to allow auto update -->
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Getting started
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---
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Install via [UPM package](#upm-package) with git reference or asset package(`UniTask.*.*.*.unitypackage`) available in [UniTask/releases](https://github.com/Cysharp/UniTask/releases).
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```csharp
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// extension awaiter/methods can be used by this namespace
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using Cysharp.Threading.Tasks;
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// You can return type as struct UniTask<T>(or UniTask), it is unity specialized lightweight alternative of Task<T>
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// zero allocation and fast excution for zero overhead async/await integrate with Unity
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async UniTask<string> DemoAsync()
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{
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// You can await Unity's AsyncObject
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var asset = await Resources.LoadAsync<TextAsset>("foo");
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var txt = (await UnityWebRequest.Get("https://...").SendWebRequest()).downloadHandler.text;
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await SceneManager.LoadSceneAsync("scene2");
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// .WithCancellation enables Cancel, GetCancellationTokenOnDestroy synchornizes with lifetime of GameObject
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// after Unity 2022.2, you can use `destroyCancellationToken` in MonoBehaviour
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var asset2 = await Resources.LoadAsync<TextAsset>("bar").WithCancellation(this.GetCancellationTokenOnDestroy());
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// .ToUniTask accepts progress callback(and all options), Progress.Create is a lightweight alternative of IProgress<T>
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var asset3 = await Resources.LoadAsync<TextAsset>("baz").ToUniTask(Progress.Create<float>(x => Debug.Log(x)));
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// await frame-based operation like a coroutine
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await UniTask.DelayFrame(100);
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// replacement of yield return new WaitForSeconds/WaitForSecondsRealtime
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await UniTask.Delay(TimeSpan.FromSeconds(10), ignoreTimeScale: false);
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// yield any playerloop timing(PreUpdate, Update, LateUpdate, etc...)
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await UniTask.Yield(PlayerLoopTiming.PreLateUpdate);
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// replacement of yield return null
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await UniTask.Yield();
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await UniTask.NextFrame();
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// replacement of WaitForEndOfFrame
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#if UNITY_2023_1_OR_NEWER
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await UniTask.WaitForEndOfFrame();
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#else
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// requires MonoBehaviour(CoroutineRunner))
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await UniTask.WaitForEndOfFrame(this); // this is MonoBehaviour
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#endif
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// replacement of yield return new WaitForFixedUpdate(same as UniTask.Yield(PlayerLoopTiming.FixedUpdate))
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await UniTask.WaitForFixedUpdate();
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// replacement of yield return WaitUntil
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await UniTask.WaitUntil(() => isActive == false);
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// special helper of WaitUntil
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await UniTask.WaitUntilValueChanged(this, x => x.isActive);
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// You can await IEnumerator coroutines
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await FooCoroutineEnumerator();
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// You can await a standard task
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await Task.Run(() => 100);
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// Multithreading, run on ThreadPool under this code
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await UniTask.SwitchToThreadPool();
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/* work on ThreadPool */
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// return to MainThread(same as `ObserveOnMainThread` in UniRx)
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await UniTask.SwitchToMainThread();
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// get async webrequest
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async UniTask<string> GetTextAsync(UnityWebRequest req)
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{
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var op = await req.SendWebRequest();
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return op.downloadHandler.text;
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}
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var task1 = GetTextAsync(UnityWebRequest.Get("http://google.com"));
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var task2 = GetTextAsync(UnityWebRequest.Get("http://bing.com"));
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var task3 = GetTextAsync(UnityWebRequest.Get("http://yahoo.com"));
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// concurrent async-wait and get results easily by tuple syntax
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var (google, bing, yahoo) = await UniTask.WhenAll(task1, task2, task3);
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// shorthand of WhenAll, tuple can await directly
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var (google2, bing2, yahoo2) = await (task1, task2, task3);
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// return async-value.(or you can use `UniTask`(no result), `UniTaskVoid`(fire and forget)).
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return (asset as TextAsset)?.text ?? throw new InvalidOperationException("Asset not found");
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}
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```
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Basics of UniTask and AsyncOperation
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---
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UniTask features rely on C# 7.0([task-like custom async method builder feature](https://github.com/dotnet/roslyn/blob/master/docs/features/task-types.md)) so the required Unity version is after `Unity 2018.3`, the official lowest version supported is `Unity 2018.4.13f1`.
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Why is UniTask(custom task-like object) required? Because Task is too heavy and not matched to Unity threading (single-thread). UniTask does not use threads and SynchronizationContext/ExecutionContext because Unity's asynchronous object is automaticaly dispatched by Unity's engine layer. It achieves faster and lower allocation, and is completely integrated with Unity.
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You can await `AsyncOperation`, `ResourceRequest`, `AssetBundleRequest`, `AssetBundleCreateRequest`, `UnityWebRequestAsyncOperation`, `AsyncGPUReadbackRequest`, `IEnumerator` and others when `using Cysharp.Threading.Tasks;`.
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UniTask provides three pattern of extension methods.
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```csharp
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* await asyncOperation;
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* .WithCancellation(CancellationToken);
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* .ToUniTask(IProgress, PlayerLoopTiming, CancellationToken);
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```
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`WithCancellation` is a simple version of `ToUniTask`, both return `UniTask`. For details of cancellation, see: [Cancellation and Exception handling](#cancellation-and-exception-handling) section.
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> Note: await directly is returned from native timing of PlayerLoop but WithCancellation and ToUniTask are returned from specified PlayerLoopTiming. For details of timing, see: [PlayerLoop](#playerloop) section.
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> Note: AssetBundleRequest has `asset` and `allAssets`, default await returns `asset`. If you want to get `allAssets`, you can use `AwaitForAllAssets()` method.
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The type of `UniTask` can use utilities like `UniTask.WhenAll`, `UniTask.WhenAny`, `UniTask.WhenEach`. They are like `Task.WhenAll`/`Task.WhenAny` but the return type is more useful. They return value tuples so you can deconstruct each result and pass multiple types.
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```csharp
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public async UniTaskVoid LoadManyAsync()
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{
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// parallel load.
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var (a, b, c) = await UniTask.WhenAll(
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LoadAsSprite("foo"),
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LoadAsSprite("bar"),
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LoadAsSprite("baz"));
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}
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async UniTask<Sprite> LoadAsSprite(string path)
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{
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var resource = await Resources.LoadAsync<Sprite>(path);
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return (resource as Sprite);
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}
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```
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If you want to convert a callback to UniTask, you can use `UniTaskCompletionSource<T>` which is a lightweight edition of `TaskCompletionSource<T>`.
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```csharp
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public UniTask<int> WrapByUniTaskCompletionSource()
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{
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var utcs = new UniTaskCompletionSource<int>();
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// when complete, call utcs.TrySetResult();
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// when failed, call utcs.TrySetException();
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// when cancel, call utcs.TrySetCanceled();
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return utcs.Task; //return UniTask<int>
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}
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```
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You can convert Task -> UniTask: `AsUniTask`, `UniTask` -> `UniTask<AsyncUnit>`: `AsAsyncUnitUniTask`, `UniTask<T>` -> `UniTask`: `AsUniTask`. `UniTask<T>` -> `UniTask`'s conversion cost is free.
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If you want to convert async to coroutine, you can use `.ToCoroutine()`, this is useful if you want to only allow using the coroutine system.
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UniTask can not await twice. This is a similar constraint to the [ValueTask/IValueTaskSource](https://docs.microsoft.com/en-us/dotnet/api/system.threading.tasks.valuetask-1?view=netcore-3.1) introduced in .NET Standard 2.1.
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> The following operations should never be performed on a ValueTask<TResult> instance:
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>
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> * Awaiting the instance multiple times.
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> * Calling AsTask multiple times.
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> * Using .Result or .GetAwaiter().GetResult() when the operation hasn't yet completed, or using them multiple times.
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> * Using more than one of these techniques to consume the instance.
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>
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> If you do any of the above, the results are undefined.
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```csharp
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var task = UniTask.DelayFrame(10);
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await task;
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await task; // NG, throws Exception
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```
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Store to the class field, you can use `UniTask.Lazy` that supports calling multiple times. `.Preserve()` allows for multiple calls (internally cached results). This is useful when there are multiple calls in a function scope.
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Also `UniTaskCompletionSource` can await multiple times and await from many callers.
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Cancellation and Exception handling
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---
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Some UniTask factory methods have a `CancellationToken cancellationToken = default` parameter. Also some async operations for Unity have `WithCancellation(CancellationToken)` and `ToUniTask(..., CancellationToken cancellation = default)` extension methods.
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You can pass `CancellationToken` to parameter by standard [`CancellationTokenSource`](https://docs.microsoft.com/en-us/dotnet/api/system.threading.cancellationtokensource).
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```csharp
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var cts = new CancellationTokenSource();
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cancelButton.onClick.AddListener(() =>
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{
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cts.Cancel();
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});
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await UnityWebRequest.Get("http://google.co.jp").SendWebRequest().WithCancellation(cts.Token);
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await UniTask.DelayFrame(1000, cancellationToken: cts.Token);
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```
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CancellationToken can be created by `CancellationTokenSource` or MonoBehaviour's extension method `GetCancellationTokenOnDestroy`.
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```csharp
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// this CancellationToken lifecycle is same as GameObject.
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await UniTask.DelayFrame(1000, cancellationToken: this.GetCancellationTokenOnDestroy());
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```
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For propagate Cancellation, all async method recommend to accept `CancellationToken cancellationToken` at last argument, and pass `CancellationToken` from root to end.
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```csharp
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await FooAsync(this.GetCancellationTokenOnDestroy());
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// ---
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async UniTask FooAsync(CancellationToken cancellationToken)
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{
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await BarAsync(cancellationToken);
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}
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async UniTask BarAsync(CancellationToken cancellationToken)
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{
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await UniTask.Delay(TimeSpan.FromSeconds(3), cancellationToken);
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}
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```
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`CancellationToken` means lifecycle of async. You can hold your own lifecycle insteadof default CancellationTokenOnDestroy.
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```csharp
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public class MyBehaviour : MonoBehaviour
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{
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CancellationTokenSource disableCancellation = new CancellationTokenSource();
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CancellationTokenSource destroyCancellation = new CancellationTokenSource();
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private void OnEnable()
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{
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if (disableCancellation != null)
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{
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disableCancellation.Dispose();
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}
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disableCancellation = new CancellationTokenSource();
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}
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private void OnDisable()
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{
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disableCancellation.Cancel();
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}
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private void OnDestroy()
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{
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destroyCancellation.Cancel();
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destroyCancellation.Dispose();
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}
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}
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```
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After Unity 2022.2, Unity adds CancellationToken in [MonoBehaviour.destroyCancellationToken](https://docs.unity3d.com/ScriptReference/MonoBehaviour-destroyCancellationToken.html) and [Application.exitCancellationToken](https://docs.unity3d.com/ScriptReference/Application-exitCancellationToken.html).
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When cancellation is detected, all methods throw `OperationCanceledException` and propagate upstream. When exception(not limited to `OperationCanceledException`) is not handled in async method, it is propagated finally to `UniTaskScheduler.UnobservedTaskException`. The default behaviour of received unhandled exception is to write log as exception. Log level can be changed using `UniTaskScheduler.UnobservedExceptionWriteLogType`. If you want to use custom behaviour, set an action to `UniTaskScheduler.UnobservedTaskException.`
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And also `OperationCanceledException` is a special exception, this is silently ignored at `UnobservedTaskException`.
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If you want to cancel behaviour in an async UniTask method, throw `OperationCanceledException` manually.
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```csharp
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public async UniTask<int> FooAsync()
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{
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await UniTask.Yield();
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throw new OperationCanceledException();
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}
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```
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If you handle an exception but want to ignore(propagate to global cancellation handling), use an exception filter.
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```csharp
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public async UniTask<int> BarAsync()
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{
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try
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{
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var x = await FooAsync();
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return x * 2;
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}
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catch (Exception ex) when (!(ex is OperationCanceledException)) // when (ex is not OperationCanceledException) at C# 9.0
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{
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return -1;
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}
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}
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```
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throws/catch `OperationCanceledException` is slightly heavy, so if performance is a concern, use `UniTask.SuppressCancellationThrow` to avoid OperationCanceledException throw. It returns `(bool IsCanceled, T Result)` instead of throwing.
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```csharp
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var (isCanceled, _) = await UniTask.DelayFrame(10, cancellationToken: cts.Token).SuppressCancellationThrow();
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if (isCanceled)
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{
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// ...
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}
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```
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Note: Only suppress throws if you call directly into the most source method. Otherwise, the return value will be converted, but the entire pipeline will not suppress throws.
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Some features that use Unity's player loop, such as `UniTask.Yield` and `UniTask.Delay` etc, determines CancellationToken state on the player loop.
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This means it does not cancel immediately upon `CancellationToken` fired.
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If you want to change this behaviour, the cancellation to be immediate, set the `cancelImmediately` flag as an argument.
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```csharp
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await UniTask.Yield(cancellationToken, cancelImmediately: true);
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```
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Note: Setting `cancelImmediately` to true and detecting an immediate cancellation is more costly than the default behavior.
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This is because it uses `CancellationToken.Register`; it is heavier than checking CancellationToken on the player loop.
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Timeout handling
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---
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Timeout is a variation of cancellation. You can set timeout by `CancellationTokenSouce.CancelAfterSlim(TimeSpan)` and pass CancellationToken to async methods.
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```csharp
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var cts = new CancellationTokenSource();
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cts.CancelAfterSlim(TimeSpan.FromSeconds(5)); // 5sec timeout.
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try
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{
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await UnityWebRequest.Get("http://foo").SendWebRequest().WithCancellation(cts.Token);
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}
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catch (OperationCanceledException ex)
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{
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if (ex.CancellationToken == cts.Token)
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{
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UnityEngine.Debug.Log("Timeout");
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}
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}
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```
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> `CancellationTokenSouce.CancelAfter` is a standard api. However in Unity you should not use it because it depends threading timer. `CancelAfterSlim` is UniTask's extension methods, it uses PlayerLoop instead.
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If you want to use timeout with other source of cancellation, use `CancellationTokenSource.CreateLinkedTokenSource`.
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```csharp
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var cancelToken = new CancellationTokenSource();
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cancelButton.onClick.AddListener(() =>
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{
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cancelToken.Cancel(); // cancel from button click.
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});
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var timeoutToken = new CancellationTokenSource();
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timeoutToken.CancelAfterSlim(TimeSpan.FromSeconds(5)); // 5sec timeout.
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try
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{
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// combine token
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var linkedTokenSource = CancellationTokenSource.CreateLinkedTokenSource(cancelToken.Token, timeoutToken.Token);
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await UnityWebRequest.Get("http://foo").SendWebRequest().WithCancellation(linkedTokenSource.Token);
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}
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catch (OperationCanceledException ex)
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{
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if (timeoutToken.IsCancellationRequested)
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{
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UnityEngine.Debug.Log("Timeout.");
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}
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else if (cancelToken.IsCancellationRequested)
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{
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UnityEngine.Debug.Log("Cancel clicked.");
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}
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}
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```
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Optimize for reduce allocation of CancellationTokenSource for timeout per call async method, you can use UniTask's `TimeoutController`.
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```csharp
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TimeoutController timeoutController = new TimeoutController(); // setup to field for reuse.
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async UniTask FooAsync()
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{
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try
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{
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// you can pass timeoutController.Timeout(TimeSpan) to cancellationToken.
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await UnityWebRequest.Get("http://foo").SendWebRequest()
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.WithCancellation(timeoutController.Timeout(TimeSpan.FromSeconds(5)));
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timeoutController.Reset(); // call Reset(Stop timeout timer and ready for reuse) when succeed.
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}
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catch (OperationCanceledException ex)
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{
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if (timeoutController.IsTimeout())
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{
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UnityEngine.Debug.Log("timeout");
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}
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}
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}
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```
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If you want to use timeout with other source of cancellation, use `new TimeoutController(CancellationToken)`.
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```csharp
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TimeoutController timeoutController;
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CancellationTokenSource clickCancelSource;
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void Start()
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{
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this.clickCancelSource = new CancellationTokenSource();
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this.timeoutController = new TimeoutController(clickCancelSource);
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}
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```
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Note: UniTask has `.Timeout`, `.TimeoutWithoutException` methods however, if possible, do not use these, please pass `CancellationToken`. Because `.Timeout` work from external of task, can not stop timeoutted task. `.Timeout` means ignore result when timeout. If you pass a `CancellationToken` to the method, it will act from inside of the task, so it is possible to stop a running task.
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Progress
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|
---
|
|
Some async operations for unity have `ToUniTask(IProgress<float> progress = null, ...)` extension methods.
|
|
|
|
```csharp
|
|
var progress = Progress.Create<float>(x => Debug.Log(x));
|
|
|
|
var request = await UnityWebRequest.Get("http://google.co.jp")
|
|
.SendWebRequest()
|
|
.ToUniTask(progress: progress);
|
|
```
|
|
|
|
You should not use standard `new System.Progress<T>`, because it causes allocation every time. Use `Cysharp.Threading.Tasks.Progress` instead. This progress factory has two methods, `Create` and `CreateOnlyValueChanged`. `CreateOnlyValueChanged` calls only when the progress value has changed.
|
|
|
|
Implementing IProgress interface to caller is better as there is no lambda allocation.
|
|
|
|
```csharp
|
|
public class Foo : MonoBehaviour, IProgress<float>
|
|
{
|
|
public void Report(float value)
|
|
{
|
|
UnityEngine.Debug.Log(value);
|
|
}
|
|
|
|
public async UniTaskVoid WebRequest()
|
|
{
|
|
var request = await UnityWebRequest.Get("http://google.co.jp")
|
|
.SendWebRequest()
|
|
.ToUniTask(progress: this); // pass this
|
|
}
|
|
}
|
|
```
|
|
|
|
PlayerLoop
|
|
---
|
|
UniTask is run on a custom [PlayerLoop](https://docs.unity3d.com/ScriptReference/LowLevel.PlayerLoop.html). UniTask's playerloop based methods (such as `Delay`, `DelayFrame`, `asyncOperation.ToUniTask`, etc...) accept this `PlayerLoopTiming`.
|
|
|
|
```csharp
|
|
public enum PlayerLoopTiming
|
|
{
|
|
Initialization = 0,
|
|
LastInitialization = 1,
|
|
|
|
EarlyUpdate = 2,
|
|
LastEarlyUpdate = 3,
|
|
|
|
FixedUpdate = 4,
|
|
LastFixedUpdate = 5,
|
|
|
|
PreUpdate = 6,
|
|
LastPreUpdate = 7,
|
|
|
|
Update = 8,
|
|
LastUpdate = 9,
|
|
|
|
PreLateUpdate = 10,
|
|
LastPreLateUpdate = 11,
|
|
|
|
PostLateUpdate = 12,
|
|
LastPostLateUpdate = 13
|
|
|
|
#if UNITY_2020_2_OR_NEWER
|
|
TimeUpdate = 14,
|
|
LastTimeUpdate = 15,
|
|
#endif
|
|
}
|
|
```
|
|
|
|
It indicates when to run, you can check [PlayerLoopList.md](https://gist.github.com/neuecc/bc3a1cfd4d74501ad057e49efcd7bdae) to Unity's default playerloop and injected UniTask's custom loop.
|
|
|
|
`PlayerLoopTiming.Update` is similar to `yield return null` in a coroutine, but it is called before Update(Update and uGUI events(button.onClick, etc...) are called on `ScriptRunBehaviourUpdate`, yield return null is called on `ScriptRunDelayedDynamicFrameRate`). `PlayerLoopTiming.FixedUpdate` is similar to `WaitForFixedUpdate`.
|
|
|
|
> `PlayerLoopTiming.LastPostLateUpdate` is not equivalent to coroutine's `yield return new WaitForEndOfFrame()`. Coroutine's WaitForEndOfFrame seems to run after the PlayerLoop is done. Some methods that require coroutine's end of frame(`Texture2D.ReadPixels`, `ScreenCapture.CaptureScreenshotAsTexture`, `CommandBuffer`, etc) do not work correctly when replaced with async/await. In these cases, pass MonoBehaviour(coroutine runnner) to `UniTask.WaitForEndOfFrame`. For example, `await UniTask.WaitForEndOfFrame(this);` is lightweight allocation free alternative of `yield return new WaitForEndOfFrame()`.
|
|
>
|
|
> Note: In Unity 2023.1 or newer, `await UniTask.WaitForEndOfFrame();` no longer requires MonoBehaviour. It uses `UnityEngine.Awaitable.EndOfFrameAsync`.
|
|
|
|
`yield return null` and `UniTask.Yield` are similar but different. `yield return null` always returns next frame but `UniTask.Yield` returns next called. That is, call `UniTask.Yield(PlayerLoopTiming.Update)` on `PreUpdate`, it returns same frame. `UniTask.NextFrame()` guarantees return next frame, you can expect this to behave exactly the same as `yield return null`.
|
|
|
|
> UniTask.Yield(without CancellationToken) is a special type, returns `YieldAwaitable` and runs on YieldRunner. It is the most lightweight and fastest.
|
|
|
|
`AsyncOperation` is returned from native timing. For example, await `SceneManager.LoadSceneAsync` is returned from `EarlyUpdate.UpdatePreloading` and after being called, the loaded scene's `Start` is called from `EarlyUpdate.ScriptRunDelayedStartupFrame`. Also `await UnityWebRequest` is returned from `EarlyUpdate.ExecuteMainThreadJobs`.
|
|
|
|
In UniTask, await directly uses native timing, while `WithCancellation` and `ToUniTask` use specified timing. This is usually not a particular problem, but with `LoadSceneAsync`, it causes a different order of Start and continuation after await. So it is recommended not to use `LoadSceneAsync.ToUniTask`.
|
|
|
|
> Note: When using Unity 2023.1 or newer, ensure you have `using UnityEngine;` in the using statements of your file when working with new `UnityEngine.Awaitable` methods like `SceneManager.LoadSceneAsync`.
|
|
> This prevents compilation errors by avoiding the use of the `UnityEngine.AsyncOperation` version.
|
|
|
|
In the stacktrace, you can check where it is running in playerloop.
|
|
|
|
|
|
|
|
By default, UniTask's PlayerLoop is initialized at `[RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.BeforeSceneLoad)]`.
|
|
|
|
The order in which methods are called in BeforeSceneLoad is nondeterministic, so if you want to use UniTask in other BeforeSceneLoad methods, you should try to initialize it before this.
|
|
|
|
```csharp
|
|
// AfterAssembliesLoaded is called before BeforeSceneLoad
|
|
[RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.AfterAssembliesLoaded)]
|
|
public static void InitUniTaskLoop()
|
|
{
|
|
var loop = PlayerLoop.GetCurrentPlayerLoop();
|
|
Cysharp.Threading.Tasks.PlayerLoopHelper.Initialize(ref loop);
|
|
}
|
|
```
|
|
|
|
If you import Unity's `Entities` package, that resets the custom player loop to default at `BeforeSceneLoad` and injects ECS's loop. When Unity calls ECS's inject method after UniTask's initialize method, UniTask will no longer work.
|
|
|
|
To solve this issue, you can re-initialize the UniTask PlayerLoop after ECS is initialized.
|
|
|
|
```csharp
|
|
// Get ECS Loop.
|
|
var playerLoop = ScriptBehaviourUpdateOrder.CurrentPlayerLoop;
|
|
|
|
// Setup UniTask's PlayerLoop.
|
|
PlayerLoopHelper.Initialize(ref playerLoop);
|
|
```
|
|
|
|
You can diagnose whether UniTask's player loop is ready by calling `PlayerLoopHelper.IsInjectedUniTaskPlayerLoop()`. And also `PlayerLoopHelper.DumpCurrentPlayerLoop` logs all current playerloops to console.
|
|
|
|
```csharp
|
|
void Start()
|
|
{
|
|
UnityEngine.Debug.Log("UniTaskPlayerLoop ready? " + PlayerLoopHelper.IsInjectedUniTaskPlayerLoop());
|
|
PlayerLoopHelper.DumpCurrentPlayerLoop();
|
|
}
|
|
```
|
|
|
|
You can optimize loop cost slightly by remove unuse PlayerLoopTiming injection. You can call `PlayerLoopHelper.Initialize(InjectPlayerLoopTimings)` on initialize.
|
|
|
|
```csharp
|
|
var loop = PlayerLoop.GetCurrentPlayerLoop();
|
|
PlayerLoopHelper.Initialize(ref loop, InjectPlayerLoopTimings.Minimum); // minimum is Update | FixedUpdate | LastPostLateUpdate
|
|
```
|
|
|
|
`InjectPlayerLoopTimings` has three preset, `All` and `Standard`(All without last except LastPostLateUpdate), `Minimum`(`Update | FixedUpdate | LastPostLateUpdate`). Default is All and you can combine custom inject timings like `InjectPlayerLoopTimings.Update | InjectPlayerLoopTimings.FixedUpdate | InjectPlayerLoopTimings.PreLateUpdate`.
|
|
|
|
You can make error to use uninjected `PlayerLoopTiming` by [Microsoft.CodeAnalysis.BannedApiAnalyzers](https://github.com/dotnet/roslyn-analyzers/blob/master/src/Microsoft.CodeAnalysis.BannedApiAnalyzers/BannedApiAnalyzers.Help.md). For example, you can setup `BannedSymbols.txt` like this for `InjectPlayerLoopTimings.Minimum`.
|
|
|
|
```txt
|
|
F:Cysharp.Threading.Tasks.PlayerLoopTiming.Initialization; Isn't injected this PlayerLoop in this project.
|
|
F:Cysharp.Threading.Tasks.PlayerLoopTiming.LastInitialization; Isn't injected this PlayerLoop in this project.
|
|
F:Cysharp.Threading.Tasks.PlayerLoopTiming.EarlyUpdate; Isn't injected this PlayerLoop in this project.
|
|
F:Cysharp.Threading.Tasks.PlayerLoopTiming.LastEarlyUpdate; Isn't injected this PlayerLoop in this project.d
|
|
F:Cysharp.Threading.Tasks.PlayerLoopTiming.LastFixedUpdate; Isn't injected this PlayerLoop in this project.
|
|
F:Cysharp.Threading.Tasks.PlayerLoopTiming.PreUpdate; Isn't injected this PlayerLoop in this project.
|
|
F:Cysharp.Threading.Tasks.PlayerLoopTiming.LastPreUpdate; Isn't injected this PlayerLoop in this project.
|
|
F:Cysharp.Threading.Tasks.PlayerLoopTiming.LastUpdate; Isn't injected this PlayerLoop in this project.
|
|
F:Cysharp.Threading.Tasks.PlayerLoopTiming.PreLateUpdate; Isn't injected this PlayerLoop in this project.
|
|
F:Cysharp.Threading.Tasks.PlayerLoopTiming.LastPreLateUpdate; Isn't injected this PlayerLoop in this project.
|
|
F:Cysharp.Threading.Tasks.PlayerLoopTiming.PostLateUpdate; Isn't injected this PlayerLoop in this project.
|
|
F:Cysharp.Threading.Tasks.PlayerLoopTiming.TimeUpdate; Isn't injected this PlayerLoop in this project.
|
|
F:Cysharp.Threading.Tasks.PlayerLoopTiming.LastTimeUpdate; Isn't injected this PlayerLoop in this project.
|
|
```
|
|
|
|
You can configure `RS0030` severity to error.
|
|
|
|
|
|
|
|
async void vs async UniTaskVoid
|
|
---
|
|
`async void` is a standard C# task system so it does not run on UniTask systems. It is better not to use it. `async UniTaskVoid` is a lightweight version of `async UniTask` because it does not have awaitable completion and reports errors immediately to `UniTaskScheduler.UnobservedTaskException`. If you don't require awaiting (fire and forget), using `UniTaskVoid` is better. Unfortunately to dismiss warning, you're required to call `Forget()`.
|
|
|
|
```csharp
|
|
public async UniTaskVoid FireAndForgetMethod()
|
|
{
|
|
// do anything...
|
|
await UniTask.Yield();
|
|
}
|
|
|
|
public void Caller()
|
|
{
|
|
FireAndForgetMethod().Forget();
|
|
}
|
|
```
|
|
|
|
Also UniTask has the `Forget` method, it is similar to `UniTaskVoid` and has the same effects. However `UniTaskVoid` is more efficient if you completely don't use `await`。
|
|
|
|
```csharp
|
|
public async UniTask DoAsync()
|
|
{
|
|
// do anything...
|
|
await UniTask.Yield();
|
|
}
|
|
|
|
public void Caller()
|
|
{
|
|
DoAsync().Forget();
|
|
}
|
|
```
|
|
|
|
To use an async lambda registered to an event, don't use `async void`. Instead you can use `UniTask.Action` or `UniTask.UnityAction`, both of which create a delegate via `async UniTaskVoid` lambda.
|
|
|
|
```csharp
|
|
Action actEvent;
|
|
UnityAction unityEvent; // especially used in uGUI
|
|
|
|
// Bad: async void
|
|
actEvent += async () => { };
|
|
unityEvent += async () => { };
|
|
|
|
// Ok: create Action delegate by lambda
|
|
actEvent += UniTask.Action(async () => { await UniTask.Yield(); });
|
|
unityEvent += UniTask.UnityAction(async () => { await UniTask.Yield(); });
|
|
```
|
|
|
|
`UniTaskVoid` can also be used in MonoBehaviour's `Start` method.
|
|
|
|
```csharp
|
|
class Sample : MonoBehaviour
|
|
{
|
|
async UniTaskVoid Start()
|
|
{
|
|
// async init code.
|
|
}
|
|
}
|
|
```
|
|
|
|
UniTaskTracker
|
|
---
|
|
useful for checking (leaked) UniTasks. You can open tracker window in `Window -> UniTask Tracker`.
|
|
|
|
|
|
|
|
* Enable AutoReload(Toggle) - Reload automatically.
|
|
* Reload - Reload view.
|
|
* GC.Collect - Invoke GC.Collect.
|
|
* Enable Tracking(Toggle) - Start to track async/await UniTask. Performance impact: low.
|
|
* Enable StackTrace(Toggle) - Capture StackTrace when task is started. Performance impact: high.
|
|
|
|
UniTaskTracker is intended for debugging use only as enabling tracking and capturing stacktraces is useful but has a heavy performance impact. Recommended usage is to enable both tracking and stacktraces to find task leaks and to disable them both when done.
|
|
|
|
External Assets
|
|
---
|
|
By default, UniTask supports TextMeshPro(`BindTo(TMP_Text)` and `TMP_InputField` event extensions like standard uGUI `InputField`), DOTween(`Tween` as awaitable) and Addressables(`AsyncOperationHandle` and `AsyncOperationHandle<T>` as awaitable).
|
|
|
|
There are defined in separated asmdefs like `UniTask.TextMeshPro`, `UniTask.DOTween`, `UniTask.Addressables`.
|
|
|
|
TextMeshPro and Addressables support are automatically enabled when importing their packages from package manager.
|
|
However for DOTween support, after importing from the [DOTWeen assets](https://assetstore.unity.com/packages/tools/animation/dotween-hotween-v2-27676r) and define the scripting define symbol `UNITASK_DOTWEEN_SUPPORT` to enable it.
|
|
|
|
```csharp
|
|
// sequential
|
|
await transform.DOMoveX(2, 10);
|
|
await transform.DOMoveZ(5, 20);
|
|
|
|
// parallel with cancellation
|
|
var ct = this.GetCancellationTokenOnDestroy();
|
|
|
|
await UniTask.WhenAll(
|
|
transform.DOMoveX(10, 3).WithCancellation(ct),
|
|
transform.DOScale(10, 3).WithCancellation(ct));
|
|
```
|
|
|
|
DOTween support's default behaviour(`await`, `WithCancellation`, `ToUniTask`) awaits tween is killed. It works on both Complete(true/false) and Kill(true/false). But if you want to reuse tweens (`SetAutoKill(false)`), it does not work as expected. If you want to await for another timing, the following extension methods exist in Tween, `AwaitForComplete`, `AwaitForPause`, `AwaitForPlay`, `AwaitForRewind`, `AwaitForStepComplete`.
|
|
|
|
AsyncEnumerable and Async LINQ
|
|
---
|
|
Unity 2020.2 supports C# 8.0 so you can use `await foreach`. This is the new Update notation in the async era.
|
|
|
|
```csharp
|
|
// Unity 2020.2, C# 8.0
|
|
await foreach (var _ in UniTaskAsyncEnumerable.EveryUpdate().WithCancellation(token))
|
|
{
|
|
Debug.Log("Update() " + Time.frameCount);
|
|
}
|
|
```
|
|
|
|
In a C# 7.3 environment, you can use the `ForEachAsync` method to work in almost the same way.
|
|
|
|
```csharp
|
|
// C# 7.3(Unity 2018.3~)
|
|
await UniTaskAsyncEnumerable.EveryUpdate().ForEachAsync(_ =>
|
|
{
|
|
Debug.Log("Update() " + Time.frameCount);
|
|
}, token);
|
|
```
|
|
|
|
`UniTask.WhenEach` that is similar to .NET 9's `Task.WhenEach` can consume new way for await multiple tasks.
|
|
|
|
```csharp
|
|
await foreach (var result in UniTask.WhenEach(task1, task2, task3))
|
|
{
|
|
// The result is of type WhenEachResult<T>.
|
|
// It contains either `T Result` or `Exception Exception`.
|
|
// You can check `IsCompletedSuccessfully` or `IsFaulted` to determine whether to access `.Result` or `.Exception`.
|
|
// If you want to throw an exception when `IsFaulted` and retrieve the result when successful, use `GetResult()`.
|
|
Debug.Log(result.GetResult());
|
|
}
|
|
```
|
|
|
|
UniTaskAsyncEnumerable implements asynchronous LINQ, similar to LINQ in `IEnumerable<T>` or Rx in `IObservable<T>`. All standard LINQ query operators can be applied to asynchronous streams. For example, the following code shows how to apply a Where filter to a button-click asynchronous stream that runs once every two clicks.
|
|
|
|
```csharp
|
|
await okButton.OnClickAsAsyncEnumerable().Where((x, i) => i % 2 == 0).ForEachAsync(_ =>
|
|
{
|
|
});
|
|
```
|
|
|
|
Fire and Forget style(for example, event handling), you can also use `Subscribe`.
|
|
|
|
```csharp
|
|
okButton.OnClickAsAsyncEnumerable().Where((x, i) => i % 2 == 0).Subscribe(_ =>
|
|
{
|
|
});
|
|
```
|
|
|
|
Async LINQ is enabled when `using Cysharp.Threading.Tasks.Linq;`, and `UniTaskAsyncEnumerable` is defined in `UniTask.Linq` asmdef.
|
|
|
|
It's closer to UniRx (Reactive Extensions), but UniTaskAsyncEnumerable is a pull-based asynchronous stream, whereas Rx was a push-based asynchronous stream. Note that although similar, the characteristics are different and the details behave differently along with them.
|
|
|
|
`UniTaskAsyncEnumerable` is the entry point like `Enumerable`. In addition to the standard query operators, there are other generators for Unity such as `EveryUpdate`, `Timer`, `TimerFrame`, `Interval`, `IntervalFrame`, and `EveryValueChanged`. And also added additional UniTask original query operators like `Append`, `Prepend`, `DistinctUntilChanged`, `ToHashSet`, `Buffer`, `CombineLatest`,`Merge` `Do`, `Never`, `ForEachAsync`, `Pairwise`, `Publish`, `Queue`, `Return`, `SkipUntil`, `TakeUntil`, `SkipUntilCanceled`, `TakeUntilCanceled`, `TakeLast`, `Subscribe`.
|
|
|
|
The method with Func as an argument has three additional overloads, `***Await`, `***AwaitWithCancellation`.
|
|
|
|
```csharp
|
|
Select(Func<T, TR> selector)
|
|
SelectAwait(Func<T, UniTask<TR>> selector)
|
|
SelectAwaitWithCancellation(Func<T, CancellationToken, UniTask<TR>> selector)
|
|
```
|
|
|
|
If you want to use the `async` method inside the func, use the `***Await` or `***AwaitWithCancellation`.
|
|
|
|
How to create an async iterator: C# 8.0 supports async iterator(`async yield return`) but it only allows `IAsyncEnumerable<T>` and of course requires C# 8.0. UniTask supports `UniTaskAsyncEnumerable.Create` method to create custom async iterator.
|
|
|
|
```csharp
|
|
// IAsyncEnumerable, C# 8.0 version of async iterator. ( do not use this style, IAsyncEnumerable is not controled in UniTask).
|
|
public async IAsyncEnumerable<int> MyEveryUpdate([EnumeratorCancellation]CancellationToken cancelationToken = default)
|
|
{
|
|
var frameCount = 0;
|
|
await UniTask.Yield();
|
|
while (!token.IsCancellationRequested)
|
|
{
|
|
yield return frameCount++;
|
|
await UniTask.Yield();
|
|
}
|
|
}
|
|
|
|
// UniTaskAsyncEnumerable.Create and use `await writer.YieldAsync` instead of `yield return`.
|
|
public IUniTaskAsyncEnumerable<int> MyEveryUpdate()
|
|
{
|
|
// writer(IAsyncWriter<T>) has `YieldAsync(value)` method.
|
|
return UniTaskAsyncEnumerable.Create<int>(async (writer, token) =>
|
|
{
|
|
var frameCount = 0;
|
|
await UniTask.Yield();
|
|
while (!token.IsCancellationRequested)
|
|
{
|
|
await writer.YieldAsync(frameCount++); // instead of `yield return`
|
|
await UniTask.Yield();
|
|
}
|
|
});
|
|
}
|
|
```
|
|
|
|
Awaitable Events
|
|
---
|
|
All uGUI component implements `***AsAsyncEnumerable` to convert asynchronous streams of events.
|
|
|
|
```csharp
|
|
async UniTask TripleClick()
|
|
{
|
|
// In default, used button.GetCancellationTokenOnDestroy to manage lieftime of async
|
|
await button.OnClickAsync();
|
|
await button.OnClickAsync();
|
|
await button.OnClickAsync();
|
|
Debug.Log("Three times clicked");
|
|
}
|
|
|
|
// more efficient way
|
|
async UniTask TripleClick()
|
|
{
|
|
using (var handler = button.GetAsyncClickEventHandler())
|
|
{
|
|
await handler.OnClickAsync();
|
|
await handler.OnClickAsync();
|
|
await handler.OnClickAsync();
|
|
Debug.Log("Three times clicked");
|
|
}
|
|
}
|
|
|
|
// use async LINQ
|
|
async UniTask TripleClick(CancellationToken token)
|
|
{
|
|
await button.OnClickAsAsyncEnumerable().Take(3).Last();
|
|
Debug.Log("Three times clicked");
|
|
}
|
|
|
|
// use async LINQ2
|
|
async UniTask TripleClick(CancellationToken token)
|
|
{
|
|
await button.OnClickAsAsyncEnumerable().Take(3).ForEachAsync(_ =>
|
|
{
|
|
Debug.Log("Every clicked");
|
|
});
|
|
Debug.Log("Three times clicked, complete.");
|
|
}
|
|
```
|
|
|
|
All MonoBehaviour message events can convert async-streams by `AsyncTriggers` that can be enabled by `using Cysharp.Threading.Tasks.Triggers;`. AsyncTrigger can be created using `GetAsync***Trigger` and triggers itself as UniTaskAsyncEnumerable.
|
|
|
|
```csharp
|
|
var trigger = this.GetOnCollisionEnterAsyncHandler();
|
|
await trigger.OnCollisionEnterAsync();
|
|
await trigger.OnCollisionEnterAsync();
|
|
await trigger.OnCollisionEnterAsync();
|
|
|
|
// every moves.
|
|
await this.GetAsyncMoveTrigger().ForEachAsync(axisEventData =>
|
|
{
|
|
});
|
|
```
|
|
|
|
`AsyncReactiveProperty`, `AsyncReadOnlyReactiveProperty` is UniTask's version of ReactiveProperty. `BindTo` extension method of `IUniTaskAsyncEnumerable<T>` for binding asynchronous stream values to Unity components(Text/Selectable/TMP/Text).
|
|
|
|
```csharp
|
|
var rp = new AsyncReactiveProperty<int>(99);
|
|
|
|
// AsyncReactiveProperty itself is IUniTaskAsyncEnumerable, you can query by LINQ
|
|
rp.ForEachAsync(x =>
|
|
{
|
|
Debug.Log(x);
|
|
}, this.GetCancellationTokenOnDestroy()).Forget();
|
|
|
|
rp.Value = 10; // push 10 to all subscriber
|
|
rp.Value = 11; // push 11 to all subscriber
|
|
|
|
// WithoutCurrent ignore initial value
|
|
// BindTo bind stream value to unity components.
|
|
rp.WithoutCurrent().BindTo(this.textComponent);
|
|
|
|
await rp.WaitAsync(); // wait until next value set
|
|
|
|
// also exists ToReadOnlyAsyncReactiveProperty
|
|
var rp2 = new AsyncReactiveProperty<int>(99);
|
|
var rorp = rp.CombineLatest(rp2, (x, y) => (x, y)).ToReadOnlyAsyncReactiveProperty(CancellationToken.None);
|
|
```
|
|
|
|
A pull-type asynchronous stream does not get the next values until the asynchronous processing in the sequence is complete. This could spill data from push-type events such as buttons.
|
|
|
|
```csharp
|
|
// can not get click event during 3 seconds complete.
|
|
await button.OnClickAsAsyncEnumerable().ForEachAwaitAsync(async x =>
|
|
{
|
|
await UniTask.Delay(TimeSpan.FromSeconds(3));
|
|
});
|
|
```
|
|
|
|
It is useful (prevent double-click) but not useful sometimes.
|
|
|
|
Using the `Queue()` method will also queue events during asynchronous processing.
|
|
|
|
```csharp
|
|
// queued message in asynchronous processing
|
|
await button.OnClickAsAsyncEnumerable().Queue().ForEachAwaitAsync(async x =>
|
|
{
|
|
await UniTask.Delay(TimeSpan.FromSeconds(3));
|
|
});
|
|
```
|
|
|
|
Or use `Subscribe`, fire and forget style.
|
|
|
|
```csharp
|
|
button.OnClickAsAsyncEnumerable().Subscribe(async x =>
|
|
{
|
|
await UniTask.Delay(TimeSpan.FromSeconds(3));
|
|
});
|
|
```
|
|
|
|
Channel
|
|
---
|
|
`Channel` is the same as [System.Threading.Tasks.Channels](https://docs.microsoft.com/en-us/dotnet/api/system.threading.channels?view=netcore-3.1) which is similar to a GoLang Channel.
|
|
|
|
Currently it only supports multiple-producer, single-consumer unbounded channels. It can create by `Channel.CreateSingleConsumerUnbounded<T>()`.
|
|
|
|
For producer(`.Writer`), use `TryWrite` to push value and `TryComplete` to complete channel. For consumer(`.Reader`), use `TryRead`, `WaitToReadAsync`, `ReadAsync`, `Completion` and `ReadAllAsync` to read queued messages.
|
|
|
|
`ReadAllAsync` returns `IUniTaskAsyncEnumerable<T>` so query LINQ operators. Reader only allows single-consumer but uses `.Publish()` query operator to enable multicast message. For example, make pub/sub utility.
|
|
|
|
```csharp
|
|
public class AsyncMessageBroker<T> : IDisposable
|
|
{
|
|
Channel<T> channel;
|
|
|
|
IConnectableUniTaskAsyncEnumerable<T> multicastSource;
|
|
IDisposable connection;
|
|
|
|
public AsyncMessageBroker()
|
|
{
|
|
channel = Channel.CreateSingleConsumerUnbounded<T>();
|
|
multicastSource = channel.Reader.ReadAllAsync().Publish();
|
|
connection = multicastSource.Connect(); // Publish returns IConnectableUniTaskAsyncEnumerable.
|
|
}
|
|
|
|
public void Publish(T value)
|
|
{
|
|
channel.Writer.TryWrite(value);
|
|
}
|
|
|
|
public IUniTaskAsyncEnumerable<T> Subscribe()
|
|
{
|
|
return multicastSource;
|
|
}
|
|
|
|
public void Dispose()
|
|
{
|
|
channel.Writer.TryComplete();
|
|
connection.Dispose();
|
|
}
|
|
}
|
|
```
|
|
|
|
vs Awaitable
|
|
---
|
|
Unity 6 introduces the awaitable type, [Awaitable](https://docs.unity3d.com/6000.0/Documentation/ScriptReference/Awaitable.html). To put it simply, Awaitable can be considered a subset of UniTask, and in fact, Awaitable's design was influenced by UniTask. It should be able to handle PlayerLoop-based awaits, pooled Tasks, and support for cancellation with `CancellationToken` in a similar way. With its inclusion in the standard library, you may wonder whether to continue using UniTask or migrate to Awaitable. Here's a brief guide.
|
|
|
|
First, the functionality provided by Awaitable is equivalent to what coroutines offer. Instead of `yield return`, you use await; `await NextFrameAsync()` replaces `yield return null`; and there are equivalents for `WaitForSeconds` and `EndOfFrame`. However, that's the extent of it. Being coroutine-based in terms of functionality, it lacks Task-based features. In practical application development using async/await, operations like `WhenAll` are essential. Additionally, UniTask enables many frame-based operations (such as `DelayFrame`) and more flexible PlayerLoopTiming control, which are not available in Awaitable. Of course, there's no Tracker Window either.
|
|
|
|
Therefore, I recommend using UniTask for application development. UniTask is a superset of Awaitable and includes many essential features. For library development, where you want to avoid external dependencies, using Awaitable as a return type for methods would be appropriate. Awaitable can be converted to UniTask using `AsUniTask`, so there's no issue in handling Awaitable-based functionality within the UniTask library. Of course, if you don't need to worry about dependencies, using UniTask would be the best choice even for library development.
|
|
|
|
For Unit Testing
|
|
---
|
|
Unity's `[UnityTest]` attribute can test coroutine(IEnumerator) but can not test async. `UniTask.ToCoroutine` bridges async/await to coroutine so you can test async methods.
|
|
|
|
```csharp
|
|
[UnityTest]
|
|
public IEnumerator DelayIgnore() => UniTask.ToCoroutine(async () =>
|
|
{
|
|
var time = Time.realtimeSinceStartup;
|
|
|
|
Time.timeScale = 0.5f;
|
|
try
|
|
{
|
|
await UniTask.Delay(TimeSpan.FromSeconds(3), ignoreTimeScale: true);
|
|
|
|
var elapsed = Time.realtimeSinceStartup - time;
|
|
Assert.AreEqual(3, (int)Math.Round(TimeSpan.FromSeconds(elapsed).TotalSeconds, MidpointRounding.ToEven));
|
|
}
|
|
finally
|
|
{
|
|
Time.timeScale = 1.0f;
|
|
}
|
|
});
|
|
```
|
|
|
|
UniTask's own unit tests are written using Unity Test Runner and [Cysharp/RuntimeUnitTestToolkit](https://github.com/Cysharp/RuntimeUnitTestToolkit) to integrate with CI and check if IL2CPP is working.
|
|
|
|
ThreadPool limitation
|
|
---
|
|
Most UniTask methods run on a single thread (PlayerLoop), with only `UniTask.Run`(`Task.Run` equivalent) and `UniTask.SwitchToThreadPool` running on a thread pool. If you use a thread pool, it won't work with WebGL and so on.
|
|
|
|
`UniTask.Run` is now deprecated. You can use `UniTask.RunOnThreadPool` instead. And also consider whether you can use `UniTask.Create` or `UniTask.Void`.
|
|
|
|
IEnumerator.ToUniTask limitation
|
|
---
|
|
You can convert coroutine(IEnumerator) to UniTask(or await directly) but it has some limitations.
|
|
|
|
* `WaitForEndOfFrame`/`WaitForFixedUpdate`/`Coroutine` is not supported.
|
|
* Consuming loop timing is not the same as `StartCoroutine`, it uses the specified `PlayerLoopTiming` and the default `PlayerLoopTiming.Update` is run before MonoBehaviour's `Update` and `StartCoroutine`'s loop.
|
|
|
|
If you want fully compatible conversion from coroutine to async, use the `IEnumerator.ToUniTask(MonoBehaviour coroutineRunner)` overload. It executes StartCoroutine on an instance of the argument MonoBehaviour and waits for it to complete in UniTask.
|
|
|
|
For UnityEditor
|
|
---
|
|
UniTask can run on Unity Editor like an Editor Coroutine. However, there are some limitations.
|
|
|
|
* UniTask.Delay's DelayType.DeltaTime, UnscaledDeltaTime do not work correctly because they can not get deltaTime in editor. Therefore run on EditMode, automatically change DelayType to `DelayType.Realtime` that wait for the right time.
|
|
* All PlayerLoopTiming run on the timing `EditorApplication.update`.
|
|
* `-batchmode` with `-quit` does not work because Unity does not run `EditorApplication.update` and quit after a single frame. Instead, don't use `-quit` and quit manually with `EditorApplication.Exit(0)`.
|
|
|
|
Compare with Standard Task API
|
|
---
|
|
UniTask has many standard Task-like APIs. This table shows what the alternative apis are.
|
|
|
|
Use standard type.
|
|
|
|
| .NET Type | UniTask Type |
|
|
| --- | --- |
|
|
| `IProgress<T>` | --- |
|
|
| `CancellationToken` | --- |
|
|
| `CancellationTokenSource` | --- |
|
|
|
|
Use UniTask type.
|
|
|
|
| .NET Type | UniTask Type |
|
|
| --- | --- |
|
|
| `Task`/`ValueTask` | `UniTask` |
|
|
| `Task<T>`/`ValueTask<T>` | `UniTask<T>` |
|
|
| `async void` | `async UniTaskVoid` |
|
|
| `+= async () => { }` | `UniTask.Void`, `UniTask.Action`, `UniTask.UnityAction` |
|
|
| --- | `UniTaskCompletionSource` |
|
|
| `TaskCompletionSource<T>` | `UniTaskCompletionSource<T>`/`AutoResetUniTaskCompletionSource<T>` |
|
|
| `ManualResetValueTaskSourceCore<T>` | `UniTaskCompletionSourceCore<T>` |
|
|
| `IValueTaskSource` | `IUniTaskSource` |
|
|
| `IValueTaskSource<T>` | `IUniTaskSource<T>` |
|
|
| `ValueTask.IsCompleted` | `UniTask.Status.IsCompleted()` |
|
|
| `ValueTask<T>.IsCompleted` | `UniTask<T>.Status.IsCompleted()` |
|
|
| `new Progress<T>` | `Progress.Create<T>` |
|
|
| `CancellationToken.Register(UnsafeRegister)` | `CancellationToken.RegisterWithoutCaptureExecutionContext` |
|
|
| `CancellationTokenSource.CancelAfter` | `CancellationTokenSource.CancelAfterSlim` |
|
|
| `Channel.CreateUnbounded<T>(false){ SingleReader = true }` | `Channel.CreateSingleConsumerUnbounded<T>` |
|
|
| `IAsyncEnumerable<T>` | `IUniTaskAsyncEnumerable<T>` |
|
|
| `IAsyncEnumerator<T>` | `IUniTaskAsyncEnumerator<T>` |
|
|
| `IAsyncDisposable` | `IUniTaskAsyncDisposable` |
|
|
| `Task.Delay` | `UniTask.Delay` |
|
|
| `Task.Yield` | `UniTask.Yield` |
|
|
| `Task.Run` | `UniTask.RunOnThreadPool` |
|
|
| `Task.WhenAll` | `UniTask.WhenAll` |
|
|
| `Task.WhenAny` | `UniTask.WhenAny` |
|
|
| `Task.WhenEach` | `UniTask.WhenEach` |
|
|
| `Task.CompletedTask` | `UniTask.CompletedTask` |
|
|
| `Task.FromException` | `UniTask.FromException` |
|
|
| `Task.FromResult` | `UniTask.FromResult` |
|
|
| `Task.FromCanceled` | `UniTask.FromCanceled` |
|
|
| `Task.ContinueWith` | `UniTask.ContinueWith` |
|
|
| `TaskScheduler.UnobservedTaskException` | `UniTaskScheduler.UnobservedTaskException` |
|
|
|
|
Pooling Configuration
|
|
---
|
|
UniTask aggressively caches async promise objects to achieve zero allocation (for technical details, see blog post [UniTask v2 — Zero Allocation async/await for Unity, with Asynchronous LINQ](https://medium.com/@neuecc/unitask-v2-zero-allocation-async-await-for-unity-with-asynchronous-linq-1aa9c96aa7dd)). By default, it caches all promises but you can configure `TaskPool.SetMaxPoolSize` to your value, the value indicates cache size per type. `TaskPool.GetCacheSizeInfo` returns currently cached objects in pool.
|
|
|
|
```csharp
|
|
foreach (var (type, size) in TaskPool.GetCacheSizeInfo())
|
|
{
|
|
Debug.Log(type + ":" + size);
|
|
}
|
|
```
|
|
|
|
Allocation on Profiler
|
|
---
|
|
In UnityEditor the profiler shows allocation of compiler generated AsyncStateMachine but it only occurs in debug(development) build. C# Compiler generates AsyncStateMachine as class on Debug build and as struct on Release build.
|
|
|
|
Unity supports Code Optimization option starting in 2020.1 (right, footer).
|
|
|
|
|
|
|
|
You can change C# compiler optimization to release to remove AsyncStateMachine allocation in development builds. This optimization option can also be set via `Compilation.CompilationPipeline-codeOptimization`, and `Compilation.CodeOptimization`.
|
|
|
|
UniTaskSynchronizationContext
|
|
---
|
|
Unity's default SynchronizationContext(`UnitySynchronizationContext`) is a poor implementation for performance. UniTask bypasses `SynchronizationContext`(and `ExecutionContext`) so it does not use it but if exists in `async Task`, still used it. `UniTaskSynchronizationContext` is a replacement of `UnitySynchronizationContext` which is better for performance.
|
|
|
|
```csharp
|
|
public class SyncContextInjecter
|
|
{
|
|
[RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.SubsystemRegistration)]
|
|
public static void Inject()
|
|
{
|
|
SynchronizationContext.SetSynchronizationContext(new UniTaskSynchronizationContext());
|
|
}
|
|
}
|
|
```
|
|
|
|
This is an optional choice and is not always recommended; `UniTaskSynchronizationContext` is less performant than `async UniTask` and is not a complete UniTask replacement. It also does not guarantee full behavioral compatibility with the `UnitySynchronizationContext`.
|
|
|
|
API References
|
|
---
|
|
UniTask's API References are hosted at [cysharp.github.io/UniTask](https://cysharp.github.io/UniTask/api/Cysharp.Threading.Tasks.html) by [DocFX](https://dotnet.github.io/docfx/) and [Cysharp/DocfXTemplate](https://github.com/Cysharp/DocfxTemplate).
|
|
|
|
For example, UniTask's factory methods can be seen at [UniTask#methods](https://cysharp.github.io/UniTask/api/Cysharp.Threading.Tasks.UniTask.html#methods-1). UniTaskAsyncEnumerable's factory/extension methods can be seen at [UniTaskAsyncEnumerable#methods](https://cysharp.github.io/UniTask/api/Cysharp.Threading.Tasks.Linq.UniTaskAsyncEnumerable.html#methods-1).
|
|
|
|
UPM Package
|
|
---
|
|
### Install via git URL
|
|
|
|
Requires a version of unity that supports path query parameter for git packages (Unity >= 2019.3.4f1, Unity >= 2020.1a21). You can add `https://github.com/Cysharp/UniTask.git?path=src/UniTask/Assets/Plugins/UniTask` to Package Manager
|
|
|
|
|
|
|
|
|
|
|
|
or add `"com.cysharp.unitask": "https://github.com/Cysharp/UniTask.git?path=src/UniTask/Assets/Plugins/UniTask"` to `Packages/manifest.json`.
|
|
|
|
If you want to set a target version, UniTask uses the `*.*.*` release tag so you can specify a version like `#2.1.0`. For example `https://github.com/Cysharp/UniTask.git?path=src/UniTask/Assets/Plugins/UniTask#2.1.0`.
|
|
|
|
|
|
.NET Core
|
|
---
|
|
For .NET Core, use NuGet.
|
|
|
|
> PM> Install-Package [UniTask](https://www.nuget.org/packages/UniTask)
|
|
|
|
UniTask of .NET Core version is a subset of Unity UniTask with PlayerLoop dependent methods removed.
|
|
|
|
It runs at higher performance than the standard Task/ValueTask, but you should be careful to ignore the ExecutionContext/SynchronizationContext when using it. `AsyncLocal` also does not work because it ignores ExecutionContext.
|
|
|
|
If you use UniTask internally, but provide ValueTask as an external API, you can write it like the following(Inspired by [PooledAwait](https://github.com/mgravell/PooledAwait)).
|
|
|
|
```csharp
|
|
public class ZeroAllocAsyncAwaitInDotNetCore
|
|
{
|
|
public ValueTask<int> DoAsync(int x, int y)
|
|
{
|
|
return Core(this, x, y);
|
|
|
|
static async UniTask<int> Core(ZeroAllocAsyncAwaitInDotNetCore self, int x, int y)
|
|
{
|
|
// do anything...
|
|
await Task.Delay(TimeSpan.FromSeconds(x + y));
|
|
await UniTask.Yield();
|
|
|
|
return 10;
|
|
}
|
|
}
|
|
}
|
|
|
|
// UniTask does not return to original SynchronizationContext but you can use helper `ReturnToCurrentSynchronizationContext`.
|
|
public ValueTask TestAsync()
|
|
{
|
|
await using (UniTask.ReturnToCurrentSynchronizationContext())
|
|
{
|
|
await UniTask.SwitchToThreadPool();
|
|
// do anything..
|
|
}
|
|
}
|
|
```
|
|
|
|
.NET Core version is intended to allow users to use UniTask as an interface when sharing code with Unity (such as [Cysharp/MagicOnion](https://github.com/Cysharp/MagicOnion/)). .NET Core version of UniTask enables smooth code sharing.
|
|
|
|
Utility methods such as WhenAll which are equivalent to UniTask are provided as [Cysharp/ValueTaskSupplement](https://github.com/Cysharp/ValueTaskSupplement).
|
|
|
|
License
|
|
---
|
|
This library is under the MIT License.
|