From 12c7aa87443c64df6a4988896cf44c8d93a0e999 Mon Sep 17 00:00:00 2001
From: Malcolm Daigle <mdaigle@microsoft.com>
Date: Thu, 5 Jun 2025 13:52:07 -0700
Subject: [PATCH] Add ChannelDbConnectionPool and unit tests.

---
 .../src/Microsoft.Data.SqlClient.csproj       |   3 +
 .../netfx/src/Microsoft.Data.SqlClient.csproj |   3 +
 .../ConnectionPool/ChannelDbConnectionPool.cs | 120 ++++++++++++++
 .../Microsoft.Data.SqlClient.UnitTests.csproj |   1 +
 .../ChannelDbConnectionPoolTest.cs            | 155 ++++++++++++++++++
 5 files changed, 282 insertions(+)
 create mode 100644 src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/ConnectionPool/ChannelDbConnectionPool.cs
 create mode 100644 src/Microsoft.Data.SqlClient/tests/UnitTests/Microsoft/Data/SqlClient/ConnectionPool/ChannelDbConnectionPoolTest.cs

diff --git a/src/Microsoft.Data.SqlClient/netcore/src/Microsoft.Data.SqlClient.csproj b/src/Microsoft.Data.SqlClient/netcore/src/Microsoft.Data.SqlClient.csproj
index 96b600e194..1e5ea23f79 100644
--- a/src/Microsoft.Data.SqlClient/netcore/src/Microsoft.Data.SqlClient.csproj
+++ b/src/Microsoft.Data.SqlClient/netcore/src/Microsoft.Data.SqlClient.csproj
@@ -102,6 +102,9 @@
     <Compile Include="$(CommonSourceRoot)\Microsoft\Data\ProviderBase\DbConnectionFactory.cs">
       <Link>Microsoft\Data\ProviderBase\DbConnectionFactory.cs</Link>
     </Compile>
+    <Compile Include="$(CommonSourceRoot)Microsoft\Data\SqlClient\ConnectionPool\ChannelDbConnectionPool.cs">
+      <Link>Microsoft\Data\SqlClient\ConnectionPool\ChannelDbConnectionPool.cs</Link>
+    </Compile>
     <Compile Include="$(CommonSourceRoot)Microsoft\Data\SqlClient\ConnectionPool\DbConnectionPoolAuthenticationContext.cs">
       <Link>Microsoft\Data\SqlClient\ConnectionPool\DbConnectionPoolAuthenticationContext.cs</Link>
     </Compile>
diff --git a/src/Microsoft.Data.SqlClient/netfx/src/Microsoft.Data.SqlClient.csproj b/src/Microsoft.Data.SqlClient/netfx/src/Microsoft.Data.SqlClient.csproj
index 1e736ee960..ea4950329e 100644
--- a/src/Microsoft.Data.SqlClient/netfx/src/Microsoft.Data.SqlClient.csproj
+++ b/src/Microsoft.Data.SqlClient/netfx/src/Microsoft.Data.SqlClient.csproj
@@ -288,6 +288,9 @@
     <Compile Include="$(CommonSourceRoot)Microsoft\Data\ProviderBase\DbConnectionInternal.cs">
       <Link>Microsoft\Data\ProviderBase\DbConnectionInternal.cs</Link>
     </Compile>
+    <Compile Include="$(CommonSourceRoot)Microsoft\Data\SqlClient\ConnectionPool\ChannelDbConnectionPool.cs">
+      <Link>Microsoft\Data\SqlClient\ConnectionPool\ChannelDbConnectionPool.cs</Link>
+    </Compile>
     <Compile Include="$(CommonSourceRoot)Microsoft\Data\SqlClient\ConnectionPool\DbConnectionPoolAuthenticationContext.cs">
       <Link>Microsoft\Data\SqlClient\ConnectionPool\DbConnectionPoolAuthenticationContext.cs</Link>
     </Compile>
diff --git a/src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/ConnectionPool/ChannelDbConnectionPool.cs b/src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/ConnectionPool/ChannelDbConnectionPool.cs
new file mode 100644
index 0000000000..c4772bb736
--- /dev/null
+++ b/src/Microsoft.Data.SqlClient/src/Microsoft/Data/SqlClient/ConnectionPool/ChannelDbConnectionPool.cs
@@ -0,0 +1,120 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+using System;
+using System.Collections.Concurrent;
+using System.Data.Common;
+using System.Threading.Tasks;
+using System.Transactions;
+using Microsoft.Data.Common;
+using Microsoft.Data.Common.ConnectionString;
+using Microsoft.Data.ProviderBase;
+
+#nullable enable
+
+namespace Microsoft.Data.SqlClient.ConnectionPool
+{
+    /// <summary>
+    /// A connection pool implementation based on the channel data structure.
+    /// Provides methods to manage the pool of connections, including acquiring and releasing connections.
+    /// </summary>
+    internal sealed class ChannelDbConnectionPool : IDbConnectionPool
+    {
+        #region Properties
+        /// <inheritdoc />
+        public ConcurrentDictionary<DbConnectionPoolAuthenticationContextKey, DbConnectionPoolAuthenticationContext> AuthenticationContexts => throw new NotImplementedException();
+
+        /// <inheritdoc />
+        public DbConnectionFactory ConnectionFactory => throw new NotImplementedException();
+
+        /// <inheritdoc />
+        public int Count => throw new NotImplementedException();
+
+        /// <inheritdoc />
+        public bool ErrorOccurred => throw new NotImplementedException();
+
+        /// <inheritdoc />
+        public int Id => throw new NotImplementedException();
+
+        /// <inheritdoc />
+        public DbConnectionPoolIdentity Identity => throw new NotImplementedException();
+
+        /// <inheritdoc />
+        public bool IsRunning => throw new NotImplementedException();
+
+        /// <inheritdoc />
+        public TimeSpan LoadBalanceTimeout => throw new NotImplementedException();
+
+        /// <inheritdoc />
+        public DbConnectionPoolGroup PoolGroup => throw new NotImplementedException();
+
+        /// <inheritdoc />
+        public DbConnectionPoolGroupOptions PoolGroupOptions => throw new NotImplementedException();
+
+        /// <inheritdoc />
+        public DbConnectionPoolProviderInfo ProviderInfo => throw new NotImplementedException();
+
+        /// <inheritdoc />
+        public DbConnectionPoolState State
+        {
+            get => throw new NotImplementedException();
+            set => throw new NotImplementedException();
+        }
+
+        /// <inheritdoc />
+        public bool UseLoadBalancing => throw new NotImplementedException();
+        #endregion
+
+
+
+        #region Methods
+        /// <inheritdoc />
+        public void Clear()
+        {
+            throw new NotImplementedException();
+        }
+
+        /// <inheritdoc />
+        public void PutObjectFromTransactedPool(DbConnectionInternal obj)
+        {
+            throw new NotImplementedException();
+        }
+
+        /// <inheritdoc />
+        public DbConnectionInternal ReplaceConnection(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection)
+        {
+            throw new NotImplementedException();
+        }
+
+        /// <inheritdoc />
+        public void ReturnInternalConnection(DbConnectionInternal obj, object owningObject)
+        {
+            throw new NotImplementedException();
+        }
+
+        /// <inheritdoc />
+        public void Shutdown()
+        {
+            throw new NotImplementedException();
+        }
+
+        /// <inheritdoc />
+        public void Startup()
+        {
+            throw new NotImplementedException();
+        }
+
+        /// <inheritdoc />
+        public void TransactionEnded(Transaction transaction, DbConnectionInternal transactedObject)
+        {
+            throw new NotImplementedException();
+        }
+
+        /// <inheritdoc />
+        public bool TryGetConnection(DbConnection owningObject, TaskCompletionSource<DbConnectionInternal> taskCompletionSource, DbConnectionOptions userOptions, out DbConnectionInternal connection)
+        {
+            throw new NotImplementedException();
+        }
+        #endregion
+    }
+}
diff --git a/src/Microsoft.Data.SqlClient/tests/UnitTests/Microsoft.Data.SqlClient.UnitTests.csproj b/src/Microsoft.Data.SqlClient/tests/UnitTests/Microsoft.Data.SqlClient.UnitTests.csproj
index af7c11b6b0..8f0489c292 100644
--- a/src/Microsoft.Data.SqlClient/tests/UnitTests/Microsoft.Data.SqlClient.UnitTests.csproj
+++ b/src/Microsoft.Data.SqlClient/tests/UnitTests/Microsoft.Data.SqlClient.UnitTests.csproj
@@ -30,6 +30,7 @@
   <ItemGroup Condition="$(TargetGroup) == 'netfx'">
     <PackageReference Include="System.Runtime.InteropServices.RuntimeInformation" Version="$(SystemRuntimeInteropServicesRuntimeInformationVersion)" />
     <ProjectReference Include="$(NetFxSource)src\Microsoft.Data.SqlClient.csproj" />
+	  <Reference Include="System.Transactions" />
   </ItemGroup>
   <!-- .NET references -->
   <ItemGroup Condition="'$(TargetGroup)'=='netcoreapp'">
diff --git a/src/Microsoft.Data.SqlClient/tests/UnitTests/Microsoft/Data/SqlClient/ConnectionPool/ChannelDbConnectionPoolTest.cs b/src/Microsoft.Data.SqlClient/tests/UnitTests/Microsoft/Data/SqlClient/ConnectionPool/ChannelDbConnectionPoolTest.cs
new file mode 100644
index 0000000000..2dcfe476fe
--- /dev/null
+++ b/src/Microsoft.Data.SqlClient/tests/UnitTests/Microsoft/Data/SqlClient/ConnectionPool/ChannelDbConnectionPoolTest.cs
@@ -0,0 +1,155 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using System.Data.Common;
+using System.Threading.Tasks;
+using System.Transactions;
+using Microsoft.Data.SqlClient.ConnectionPool;
+using Xunit;
+
+namespace Microsoft.Data.SqlClient.UnitTests
+{
+    public class ChannelDbConnectionPoolTest
+    {
+        private readonly ChannelDbConnectionPool _pool;
+
+        public ChannelDbConnectionPoolTest()
+        {
+            _pool = new ChannelDbConnectionPool();
+        }
+
+        [Fact]
+        public void TestAuthenticationContexts()
+        {
+            Assert.Throws<NotImplementedException>(() => _ = _pool.AuthenticationContexts);
+        }
+
+        [Fact]
+        public void TestConnectionFactory()
+        {
+            Assert.Throws<NotImplementedException>(() => _ = _pool.ConnectionFactory);
+        }
+
+        [Fact]
+        public void TestCount()
+        {
+            Assert.Throws<NotImplementedException>(() => _ = _pool.Count);
+        }
+
+        [Fact]
+        public void TestErrorOccurred()
+        {
+            Assert.Throws<NotImplementedException>(() => _ = _pool.ErrorOccurred);
+        }
+
+        [Fact]
+        public void TestId()
+        {
+            Assert.Throws<NotImplementedException>(() => _ = _pool.Id);
+        }
+
+        [Fact]
+        public void TestIdentity()
+        {
+            Assert.Throws<NotImplementedException>(() => _ = _pool.Identity);
+        }
+
+        [Fact]
+        public void TestIsRunning()
+        {
+            Assert.Throws<NotImplementedException>(() => _ = _pool.IsRunning);
+        }
+
+        [Fact]
+        public void TestLoadBalanceTimeout()
+        {
+            Assert.Throws<NotImplementedException>(() => _ = _pool.LoadBalanceTimeout);
+        }
+
+        [Fact]
+        public void TestPoolGroup()
+        {
+            Assert.Throws<NotImplementedException>(() => _ = _pool.PoolGroup);
+        }
+
+        [Fact]
+        public void TestPoolGroupOptions()
+        {
+            Assert.Throws<NotImplementedException>(() => _ = _pool.PoolGroupOptions);
+        }
+
+        [Fact]
+        public void TestProviderInfo()
+        {
+            Assert.Throws<NotImplementedException>(() => _ = _pool.ProviderInfo);
+        }
+
+        [Fact]
+        public void TestStateGetter()
+        {
+            Assert.Throws<NotImplementedException>(() => _ = _pool.State);
+        }
+
+        [Fact]
+        public void TestStateSetter()
+        {
+            Assert.Throws<NotImplementedException>(() => _pool.State = DbConnectionPoolState.Running);
+        }
+
+        [Fact]
+        public void TestUseLoadBalancing()
+        {
+            Assert.Throws<NotImplementedException>(() => _ = _pool.UseLoadBalancing);
+        }
+
+        [Fact]
+        public void TestClear()
+        {
+            Assert.Throws<NotImplementedException>(() => _pool.Clear());
+        }
+
+        [Fact]
+        public void TestPutObjectFromTransactedPool()
+        {
+            Assert.Throws<NotImplementedException>(() => _pool.PutObjectFromTransactedPool(null!));
+        }
+
+        [Fact]
+        public void TestReplaceConnection()
+        {
+            Assert.Throws<NotImplementedException>(() => _pool.ReplaceConnection(null!, null!, null!));
+        }
+
+        [Fact]
+        public void TestReturnInternalConnection()
+        {
+            Assert.Throws<NotImplementedException>(() => _pool.ReturnInternalConnection(null!, null!));
+        }
+
+        [Fact]
+        public void TestShutdown()
+        {
+            Assert.Throws<NotImplementedException>(() => _pool.Shutdown());
+        }
+
+        [Fact]
+        public void TestStartup()
+        {
+            Assert.Throws<NotImplementedException>(() => _pool.Startup());
+        }
+
+        [Fact]
+        public void TestTransactionEnded()
+        {
+            Assert.Throws<NotImplementedException>(() => _pool.TransactionEnded(null!, null!));
+        }
+
+        [Fact]
+        public void TestTryGetConnection()
+        {
+            Assert.Throws<NotImplementedException>(() => _pool.TryGetConnection(null!, null!, null!, out _));
+        }
+    }
+}