fbbrecon/streamresult

2 files changed, 12 insertions, 6 deletions

diff --git a/src/SignalR/server/Core/src/Internal/DefaultHubDispatcher.cs b/src/SignalR/server/Core/src/Internal/DefaultHubDispatcher.cs
index 508a04bb40..7e0b3f86bb 100644
--- a/src/SignalR/server/Core/src/Internal/DefaultHubDispatcher.cs
+++ b/src/SignalR/server/Core/src/Internal/DefaultHubDispatcher.cs
@@ -324,9 +324,9 @@ internal sealed partial class DefaultHubDispatcher<THub> : HubDispatcher<THub> w
                     if (hub.Clients is HubCallerClients hubCallerClients)
                     {
                         // Streaming invocations aren't involved with the semaphore.
-                        // Setting this to 0 avoids potential client result calls from the streaming hub method
+                        // Setting the semaphore released flag avoids potential client result calls from the streaming hub method
                         // releasing the semaphore which would cause a SemaphoreFullException.
-                        hubCallerClients.ShouldReleaseSemaphore = 0;
+                        hubCallerClients.TrySetSemaphoreReleased();
                     }
                 }
 
@@ -415,7 +415,7 @@ internal sealed partial class DefaultHubDispatcher<THub> : HubDispatcher<THub> w
             {
                 if (hub?.Clients is HubCallerClients hubCallerClients)
                 {
-                    wasSemaphoreReleased = Interlocked.CompareExchange(ref hubCallerClients.ShouldReleaseSemaphore, 0, 1) == 0;
+                    wasSemaphoreReleased = !hubCallerClients.TrySetSemaphoreReleased();
                 }
                 await CleanupInvocation(connection, hubMethodInvocationMessage, hubActivator, hub, scope);
             }
diff --git a/src/SignalR/server/Core/src/Internal/HubCallerClients.cs b/src/SignalR/server/Core/src/Internal/HubCallerClients.cs
index 8e6ec0fa0d..15d2c03660 100644
--- a/src/SignalR/server/Core/src/Internal/HubCallerClients.cs
+++ b/src/SignalR/server/Core/src/Internal/HubCallerClients.cs
@@ -9,7 +9,7 @@ internal sealed class HubCallerClients : IHubCallerClients
     private readonly IHubClients _hubClients;
     internal readonly ChannelBasedSemaphore _parallelInvokes;
 
-    internal int ShouldReleaseSemaphore = 1;
+    private int _shouldReleaseSemaphore = 1;
 
     // Client results don't work in OnConnectedAsync
     // This property is set by the hub dispatcher when those methods are being called
@@ -90,6 +90,12 @@ internal sealed class HubCallerClients : IHubCallerClients
         return _hubClients.Users(userIds);
     }
 
+    // false if semaphore is being released by another caller, true if you own releasing the semaphore
+    internal bool TrySetSemaphoreReleased()
+    {
+        return Interlocked.CompareExchange(ref _shouldReleaseSemaphore, 0, 1) == 1;
+    }
+
     private sealed class NoInvokeSingleClientProxy : ISingleClientProxy
     {
         private readonly ISingleClientProxy _proxy;
@@ -125,9 +131,9 @@ internal sealed class HubCallerClients : IHubCallerClients
         {
             // Releases the Channel that is blocking pending invokes, which in turn can block the receive loop.
             // Because we are waiting for a result from the client we need to let the receive loop run otherwise we'll be blocked forever
-            var value = Interlocked.CompareExchange(ref _hubCallerClients.ShouldReleaseSemaphore, 0, 1);
+            var value = _hubCallerClients.TrySetSemaphoreReleased();
             // Only release once, and we set ShouldReleaseSemaphore to 0 so the DefaultHubDispatcher knows not to call Release again
-            if (value == 1)
+            if (value)
             {
                 _hubCallerClients._parallelInvokes.Release();
             }