1 files changed, 53 insertions, 1 deletions

diff --git a/src/csharp/Grpc.Core/Internal/CompletionQueueSafeHandle.cs b/src/csharp/Grpc.Core/Internal/CompletionQueueSafeHandle.cs
index 9de2bc7950..3754ad382e 100644
--- a/src/csharp/Grpc.Core/Internal/CompletionQueueSafeHandle.cs
+++ b/src/csharp/Grpc.Core/Internal/CompletionQueueSafeHandle.cs
@@ -33,6 +33,8 @@ using System.Runtime.InteropServices;
 using System.Threading.Tasks;
 using Grpc.Core.Profiling;
 
+using Grpc.Core.Utils;
+
 namespace Grpc.Core.Internal
 {
     /// <summary>
@@ -40,6 +42,8 @@ namespace Grpc.Core.Internal
     /// </summary>
     internal class CompletionQueueSafeHandle : SafeHandleZeroIsInvalid
     {
+        AtomicCounter shutdownRefcount = new AtomicCounter(1);
+
         [DllImport("grpc_csharp_ext.dll")]
         static extern CompletionQueueSafeHandle grpcsharp_completion_queue_create();
 
@@ -62,6 +66,7 @@ namespace Grpc.Core.Internal
         public static CompletionQueueSafeHandle Create()
         {
             return grpcsharp_completion_queue_create();
+
         }
 
         public CompletionQueueEvent Next()
@@ -77,9 +82,18 @@ namespace Grpc.Core.Internal
             }
         }
 
+        /// <summary>
+        /// Creates a new usage scope for this completion queue. Once successfully created,
+        /// the completion queue won't be shutdown before scope.Dispose() is called.
+        /// </summary>
+        public UsageScope NewScope()
+        {
+            return new UsageScope(this);
+        }
+
         public void Shutdown()
         {
-            grpcsharp_completion_queue_shutdown(this);
+            DecrementShutdownRefcount();
         }
 
         protected override bool ReleaseHandle()
@@ -87,5 +101,43 @@ namespace Grpc.Core.Internal
             grpcsharp_completion_queue_destroy(handle);
             return true;
         }
+
+        private void DecrementShutdownRefcount()
+        {
+            if (shutdownRefcount.Decrement() == 0)
+            {
+                grpcsharp_completion_queue_shutdown(this);
+            }
+        }
+
+        private void BeginOp()
+        {
+            bool success = false;
+            shutdownRefcount.IncrementIfNonzero(ref success);
+            Preconditions.CheckState(success, "Shutdown has already been called");
+        }
+
+        private void EndOp()
+        {
+            DecrementShutdownRefcount();
+        }
+
+        // Allows declaring BeginOp and EndOp of a completion queue with a using statement.
+        // Declared as struct for better performance.
+        public struct UsageScope : IDisposable
+        {
+            readonly CompletionQueueSafeHandle cq;
+
+            public UsageScope(CompletionQueueSafeHandle cq)
+            {
+                this.cq = cq;
+                this.cq.BeginOp();
+            }
+
+            public void Dispose()
+            {
+                cq.EndOp();
+            }
+        }
     }
 }