Merge pull request #10 from walterlv/t/walterlv/logger

改进日志 1. 允许强行等待日志写完 2. 线程安全 3. 允许设置日志最大大小
walterlv · Jun 30, 2020 · c341901 · c341901
2 parents ee04c2d + 9ccdb2e
commit c341901
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Showing 10 changed files with 548 additions and 94 deletions.
diff --git a/build/Version.props b/build/Version.props
@@ -1,5 +1,5 @@
 <Project>
   <PropertyGroup>
-    <Version>5.2.1</Version>
+    <Version>5.3.0</Version>
   </PropertyGroup>
 </Project>
diff --git a/src/Utils/Walterlv.Collections/Threading/AsyncQueue.cs b/src/Utils/Walterlv.Collections/Threading/AsyncQueue.cs
@@ -23,6 +23,12 @@ public AsyncQueue()
             _queue = new ConcurrentQueue<T>();
         }
 
+        /// <summary>
+        /// 获取此刻队列中剩余元素的个数。
+        /// 请注意：因为线程安全问题，此值获取后值即过时，所以获取此值的代码需要自行处理线程安全。
+        /// </summary>
+        public int Count => _queue.Count;
+
         /// <summary>
         /// 入队。
         /// </summary>

diff --git a/src/Utils/Walterlv.Logger/Core/AsyncOutputLogger.AsyncQueue.cs b/src/Utils/Walterlv.Logger/Core/AsyncOutputLogger.AsyncQueue.cs
@@ -18,6 +18,8 @@ public AsyncQueue()
                 _queue = new ConcurrentQueue<T>();
             }
 
+            public int Count => _queue.Count;
+
             public void Enqueue(T item)
             {
                 _queue.Enqueue(item);
@@ -40,7 +42,6 @@ public async Task<T> DequeueAsync(CancellationToken cancellationToken = default)
                 while (true)
                 {
                     await _semaphoreSlim.WaitAsync(cancellationToken).ConfigureAwait(false);
-
                     if (_queue.TryDequeue(out var item))
                     {
                         return item;

diff --git a/src/Utils/Walterlv.Logger/Core/AsyncOutputLogger.cs b/src/Utils/Walterlv.Logger/Core/AsyncOutputLogger.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Runtime.CompilerServices;
+using System.Threading;
 using System.Threading.Tasks;
 
 namespace Walterlv.Logging.Core
@@ -11,6 +12,9 @@ public abstract partial class AsyncOutputLogger : ILogger
     {
         private readonly AsyncQueue<LogContext> _queue;
         private bool _isInitialized;
+        private CancellationTokenSource _waitForEmptyCancellationTokenSource = new CancellationTokenSource();
+        private TaskCompletionSource<object?>? _waitForEmptyTaskCompletionSource;
+        private object _waitForEmptyLocker = new object();
 
         /// <summary>
         /// 创建 Markdown 格式的日志记录实例。
@@ -108,7 +112,32 @@ private async void StartLogging()
         {
             while (true)
             {
-                var context = await _queue.DequeueAsync().ConfigureAwait(false);
+                LogContext context;
+
+                try
+                {
+                    context = await _queue.DequeueAsync(_waitForEmptyCancellationTokenSource.Token).ConfigureAwait(false);
+                    await Write(context).ConfigureAwait(false);
+                }
+                catch (OperationCanceledException)
+                {
+                    while (_queue.Count > 0)
+                    {
+                        context = await _queue.DequeueAsync().ConfigureAwait(false);
+                        await Write(context).ConfigureAwait(false);
+                    }
+                }
+
+                if (_queue.Count == 0)
+                {
+                    _waitForEmptyCancellationTokenSource.Dispose();
+                    _waitForEmptyCancellationTokenSource = new CancellationTokenSource();
+                    _waitForEmptyTaskCompletionSource?.SetResult(null);
+                }
+            }
+
+            async Task Write(LogContext context)
+            {
                 if (!_isInitialized)
                 {
                     _isInitialized = true;
@@ -128,5 +157,36 @@ private async void StartLogging()
         /// </summary>
         /// <param name="context">包含一条日志的所有上下文信息。</param>
         protected abstract void OnLogReceived(in LogContext context);
+
+        /// <summary>
+        /// 如果派生类需要等待当前尚未完成日志输出的日志全部完成输出，则调用此方法。
+        /// 但请注意：因为并发问题，如果等待期间还有新写入的日志，那么也会一并等待。
+        /// </summary>
+        /// <returns>可等待对象。</returns>
+        protected async Task WaitFlushingAsync()
+        {
+            if (_waitForEmptyTaskCompletionSource is null)
+            {
+                lock (_waitForEmptyLocker)
+                {
+                    if (_waitForEmptyTaskCompletionSource is null)
+                    {
+                        _waitForEmptyTaskCompletionSource = new TaskCompletionSource<object?>();
+                        _waitForEmptyCancellationTokenSource.Cancel();
+                    }
+                    else if (_waitForEmptyTaskCompletionSource.Task.IsCompleted)
+                    {
+                        return;
+                    }
+                }
+            }
+
+            await _waitForEmptyTaskCompletionSource.Task.ConfigureAwait(false);
+
+            lock (_waitForEmptyLocker)
+            {
+                _waitForEmptyTaskCompletionSource = null;
+            }
+        }
     }
 }