68 lines
2.4 KiB
C#
68 lines
2.4 KiB
C#
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using System;
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using System.Collections.Generic;
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using System.Linq;
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using System.Threading.Tasks;
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namespace PCL.Core.Utils.Exts;
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public static class TaskExtensions
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{
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/// <summary>
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/// 返回第一个成功完成的 Task 的结果。
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/// 如果所有 Task 都失败或被取消，则抛出 AggregateException。
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/// </summary>
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/// <typeparam name="T">Task 的返回类型</typeparam>
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/// <param name="tasks">要等待的任务集合</param>
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/// <returns>第一个成功完成的 Task 的结果</returns>
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/// <exception cref="ArgumentException">任务集合为空</exception>
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/// <exception cref="AggregateException">所有任务均未成功完成</exception>
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public static async Task<Task<T>> WhenAnySuccessAsync<T>(this IEnumerable<Task<T>> tasks)
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{
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ArgumentNullException.ThrowIfNull(tasks, nameof(tasks));
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var taskList = tasks.ToList();
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if (taskList.Count == 0)
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throw new ArgumentException("Task collection is empty.", nameof(tasks));
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var remaining = new HashSet<Task<T>>(taskList);
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while (remaining.Count > 0)
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{
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var completed = await Task.WhenAny(remaining);
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remaining.Remove(completed);
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if (completed.IsCompletedSuccessfully)
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{
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return completed;
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}
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}
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// 所有任务都失败或被取消
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var faultedExceptions = taskList
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.Where(t => t.IsFaulted)
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.SelectMany(t => t.Exception?.Flatten().InnerExceptions ?? Enumerable.Empty<Exception>())
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.ToList();
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if (faultedExceptions.Count > 0)
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{
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throw new AggregateException("All connection attempts failed.", faultedExceptions);
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}
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// 如果没有失败任务，但还有任务，为 canceled
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if (taskList.Any(t => t.IsCanceled))
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{
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throw new OperationCanceledException("All connection attempts were canceled.");
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}
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// Task 要么成功，要么 Faulted，要么 Canceled，大概率走不到这
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throw new InvalidOperationException("All tasks completed but none succeeded, failed, or canceled.");
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}
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extension(Task task)
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{
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/// <summary>
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/// 不关心 Task 后续的异常，但是需要观察下
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/// </summary>
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public void Forget()
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{
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_ = task.ContinueWith(t => _ = t.Exception, TaskContinuationOptions.OnlyOnFaulted);
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}
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}
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}
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