npgsql/src/Npgsql/Util/TaskSchedulerAwaitable.cs at main · npgsql/npgsql

35 lines (28 loc) · 1.24 KB

using System;

using System.Diagnostics;

using System.Runtime.CompilerServices;

using System.Threading;

using System.Threading.Tasks;

namespace Npgsql.Util;

readonly struct TaskSchedulerAwaitable(TaskScheduler scheduler) : ICriticalNotifyCompletion

{

public void GetResult() {}

public bool IsCompleted => false;

public void OnCompleted(Action continuation)

{

var task = Task.Factory.StartNew(continuation, CancellationToken.None,

TaskCreationOptions.DenyChildAttach,

scheduler: scheduler);

// Exceptions should never happen as the continuation should be the async statemachine.

// It normally does its own error handling through the returned task unless it's an async void returning method.

// In which case we should absolutely let it bubble up to TaskScheduler.UnobservedTaskException.

OnFaulted(task);

[Conditional("DEBUG")]

static void OnFaulted(Task task)

{

task.ContinueWith(t => Debug.Fail("Task scheduler task threw an unobserved exception"), TaskContinuationOptions.OnlyOnFaulted);

}

public void UnsafeOnCompleted(Action continuation) => OnCompleted(continuation);

public TaskSchedulerAwaitable GetAwaiter() => this;

}

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