Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.ServiceModel/System/ServiceModel/ChannelFactoryRefCache.cs

@@ -0,0 +1,122 @@
+//------------------------------------------------------------
+// Copyright (c) Microsoft Corporation.  All rights reserved.
+//------------------------------------------------------------
+
+namespace System.ServiceModel
+{
+    using System.Collections.Generic;
+    using System.Runtime;
+    using System.ServiceModel.Channels;
+    using System.ServiceModel.Diagnostics.Application;
+
+    sealed class ChannelFactoryRef<TChannel>
+        where TChannel : class
+    {
+        ChannelFactory<TChannel> channelFactory;
+        int refCount = 1;
+
+        public ChannelFactoryRef(ChannelFactory<TChannel> channelFactory)
+        {
+            this.channelFactory = channelFactory;
+        }
+
+        public void AddRef()
+        {
+            this.refCount++;
+        }
+
+        // The caller should call Close/Abort when the return value is true.
+        public bool Release()
+        {
+            --this.refCount;
+            Fx.Assert(this.refCount >= 0, "RefCount should not be less than zero.");
+
+            if (this.refCount == 0)
+            {
+                return true;
+            }
+
+            return false;
+        }
+
+        public void Close(TimeSpan timeout)
+        {
+            this.channelFactory.Close(timeout);
+        }
+
+        public void Abort()
+        {
+            this.channelFactory.Abort();
+        }
+
+        public ChannelFactory<TChannel> ChannelFactory
+        {
+            get
+            {
+                return this.channelFactory;
+            }
+        }
+    }
+
+    class ChannelFactoryRefCache<TChannel> : MruCache<EndpointTrait<TChannel>, ChannelFactoryRef<TChannel>>
+       where TChannel : class
+    {
+        static EndpointTraitComparer DefaultEndpointTraitComparer = new EndpointTraitComparer();
+        readonly int watermark;
+
+        class EndpointTraitComparer : IEqualityComparer<EndpointTrait<TChannel>>
+        {
+            public bool Equals(EndpointTrait<TChannel> x, EndpointTrait<TChannel> y)
+            {
+                if (x != null)
+                {
+                    if (y != null)
+                        return x.Equals(y);
+
+                    return false;
+                }
+
+                if (y != null)
+                    return false;
+
+                return true;
+            }
+
+            public int GetHashCode(EndpointTrait<TChannel> obj)
+            {
+                if (obj == null)
+                    return 0;
+
+                return obj.GetHashCode();
+            }
+        }
+
+        public ChannelFactoryRefCache(int watermark)
+            : base(watermark * 4 / 5, watermark, DefaultEndpointTraitComparer)
+        {
+            this.watermark = watermark;
+        }
+
+        protected override void OnSingleItemRemoved(ChannelFactoryRef<TChannel> item)
+        {
+            // Remove from cache.
+            if (item.Release())
+            {
+                item.Abort();
+            }
+
+            if (TD.ClientBaseCachedChannelFactoryCountIsEnabled())
+            {
+                TD.ClientBaseCachedChannelFactoryCount(this.Count, this.watermark, this);
+            }
+        }
+
+        protected override void OnItemAgedOutOfCache(ChannelFactoryRef<TChannel> item)
+        {
+            if (TD.ClientBaseChannelFactoryAgedOutofCacheIsEnabled())
+            {
+                TD.ClientBaseChannelFactoryAgedOutofCache(this.watermark, this);
+            }
+        }
+    }
+}