1 files changed, 88 insertions, 0 deletions
diff --git a/Rx.NET/System.Reactive.Linq/Reactive/Linq/Observαble/RefCount.cs b/Rx.NET/System.Reactive.Linq/Reactive/Linq/Observαble/RefCount.cs
new file mode 100644
index 0000000..1762807
--- /dev/null
+++ b/Rx.NET/System.Reactive.Linq/Reactive/Linq/Observαble/RefCount.cs
@@ -0,0 +1,88 @@
+// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved. See License.txt in the project root for license information.
+
+#if !NO_PERF
+using System;
+using System.Reactive.Disposables;
+using System.Reactive.Subjects;
+
+namespace System.Reactive.Linq.Observαble
+{
+    class RefCount<TSource> : Producer<TSource>
+    {
+        private readonly IConnectableObservable<TSource> _source;
+
+        private readonly object _gate;
+        private int _count;
+        private IDisposable _connectableSubscription;
+
+        public RefCount(IConnectableObservable<TSource> source)
+        {
+            _source = source;
+            _gate = new object();
+            _count = 0;
+            _connectableSubscription = default(IDisposable);
+        }
+
+        protected override IDisposable Run(IObserver<TSource> observer, IDisposable cancel, Action<IDisposable> setSink)
+        {
+            var sink = new _(this, observer, cancel);
+            setSink(sink);
+            return sink.Run();
+        }
+
+        class _ : Sink<TSource>, IObserver<TSource>
+        {
+            private readonly RefCount<TSource> _parent;
+
+            public _(RefCount<TSource> parent, IObserver<TSource> observer, IDisposable cancel)
+                : base(observer, cancel)
+            {
+                _parent = parent;
+            }
+
+            public IDisposable Run()
+            {
+                var subscription = _parent._source.SubscribeSafe(this);
+
+                lock (_parent._gate)
+                {
+                    if (++_parent._count == 1)
+                    {
+                        _parent._connectableSubscription = _parent._source.Connect();
+                    }
+                }
+
+                return Disposable.Create(() =>
+                {
+                    subscription.Dispose();
+
+                    lock (_parent._gate)
+                    {
+                        if (--_parent._count == 0)
+                        {
+                            _parent._connectableSubscription.Dispose();
+                        }
+                    }
+                });
+            }
+
+            public void OnNext(TSource value)
+            {
+                base._observer.OnNext(value);
+            }
+
+            public void OnError(Exception error)
+            {
+                base._observer.OnError(error);
+                base.Dispose();
+            }
+
+            public void OnCompleted()
+            {
+                base._observer.OnCompleted();
+                base.Dispose();
+            }
+        }
+    }
+}
+#endif