POC sql connection pool

Emby.Server.Implementations/Data/ConnectionPool.cs

@@ -0,0 +1,68 @@
+#pragma warning disable CS1591
+
+using System;
+using System.Collections.Concurrent;
+using System.Threading;
+using SQLitePCL.pretty;
+
+namespace Emby.Server.Implementations.Data;
+
+public sealed class ConnectionPool : IDisposable
+{
+    private readonly int _count;
+    private readonly SemaphoreSlim _lock;
+    private readonly ConcurrentQueue<SQLiteDatabaseConnection> _connections = new ConcurrentQueue<SQLiteDatabaseConnection>();
+    private bool _disposed;
+
+    public ConnectionPool(int count, Func<SQLiteDatabaseConnection> factory)
+    {
+        _count = count;
+        _lock = new SemaphoreSlim(count, count);
+        for (int i = 0; i < count; i++)
+        {
+            _connections.Enqueue(factory.Invoke());
+        }
+    }
+
+    public ManagedConnection GetConnection()
+    {
+        _lock.Wait();
+        if (!_connections.TryDequeue(out var connection))
+        {
+            _lock.Release();
+            throw new InvalidOperationException();
+        }
+
+        return new ManagedConnection(connection, this);
+    }
+
+    public void Return(SQLiteDatabaseConnection connection)
+    {
+        _connections.Enqueue(connection);
+        _lock.Release();
+    }
+
+    public void Dispose()
+    {
+        if (_disposed)
+        {
+            return;
+        }
+
+        for (int i = 0; i < _count; i++)
+        {
+            _lock.Wait();
+            if (!_connections.TryDequeue(out var connection))
+            {
+                _lock.Release();
+                throw new InvalidOperationException();
+            }
+
+            connection.Dispose();
+        }
+
+        _lock.Dispose();
+
+        _disposed = true;
+    }
+}