Add non-waited semaphore check (#1008)

dotnet · Apr 7, 2021 · c8ad77b · c8ad77b
1 parent 975caac
commit c8ad77b
Showing 1 changed file with 16 additions and 8 deletions.
diff --git a/src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/SqlClient/SqlUtil.cs b/src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/SqlClient/SqlUtil.cs
@@ -2152,14 +2152,22 @@ public ConcurrentQueueSemaphore(int initialCount)
 
         public Task WaitAsync(CancellationToken cancellationToken)
         {
-            var tcs = new TaskCompletionSource<bool>();
-            _queue.Enqueue(tcs);
-            _semaphore.WaitAsync().ContinueWith(
-                continuationAction: s_continuePop,
-                state: _queue,
-                cancellationToken: cancellationToken
-            );
-            return tcs.Task;
+            // try sync wait with 0 which will not block to see if we need to do an async wait
+            if (_semaphore.Wait(0, cancellationToken))
+            {
+                return Task.CompletedTask;
+            }
+            else
+            {
+                var tcs = new TaskCompletionSource<bool>();
+                _queue.Enqueue(tcs);
+                _semaphore.WaitAsync().ContinueWith(
+                    continuationAction: s_continuePop,
+                    state: _queue,
+                    cancellationToken: cancellationToken
+                );
+                return tcs.Task;
+            }
         }
 
         public void Release()