source code checkin

src/ServerManager.Common/Lib/ActionQueue.cs

@@ -0,0 +1,53 @@
+using ServerManagerTool.Common.Interfaces;
+using System;
+using System.Threading.Tasks;
+using System.Threading.Tasks.Dataflow;
+
+namespace ServerManagerTool.Common.Lib
+{
+    /// <summary>
+    /// This class ensures the following:
+    /// 1. All work items run in the order posted.
+    /// 2. Work items run on a background thread.
+    /// 3. Work items do not overlap
+    /// 4. If requested, the completion status of a work item is returned via a task.
+    /// </summary>
+    public class ActionQueue : IAsyncDisposable
+    {
+        public ActionBlock<Action> workQueue;
+
+        public ActionQueue(TaskScheduler scheduler = null)
+        {
+            this.workQueue = new ActionBlock<Action>(a => a.Invoke(), new ExecutionDataflowBlockOptions { MaxDegreeOfParallelism = 1, TaskScheduler = scheduler ?? TaskScheduler.Default });
+
+        }
+       
+        public Task<T> PostAction<T>(Func<T> action)
+        {
+            TaskCompletionSource<T> tcs = new TaskCompletionSource<T>();
+            this.workQueue.Post(() => 
+                {                    
+                    try
+                    {
+                        var result = action.Invoke();
+                        Task.Run(() => tcs.TrySetResult(result));
+                    }
+                    catch(Exception ex)
+                    {
+                        Task.Run(() => tcs.TrySetException(ex));
+                    }
+                });
+            return tcs.Task;
+        }
+
+        public Task PostAction(Action action)
+        {
+            return PostAction(() => { action.Invoke(); return true; });
+        }
+
+        public async Task DisposeAsync()
+        {
+            await PostAction(() => this.workQueue.Complete());
+        }
+    }
+}