- 修复 Ado.Query 查询字段重复时报错；#162 #165 #161 - 增加 FreeSql.Provider.MsAccess 支持 Access 数据库操作，已通过 2003/2007 版本测试；

Providers/FreeSql.Provider.MsAccess/MsAccessAdo/MsAccessConnectionPool.cs

@@ -0,0 +1,242 @@
+using SafeObjectPool;
+using System;
+using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.Data;
+using System.Data.Common;
+using System.Data.OleDb;
+using System.Text.RegularExpressions;
+using System.Threading.Tasks;
+
+namespace FreeSql.MsAccess
+{
+
+    class MsAccessConnectionPool : ObjectPool<DbConnection>
+    {
+
+        internal Action availableHandler;
+        internal Action unavailableHandler;
+
+        public MsAccessConnectionPool(string name, string connectionString, Action availableHandler, Action unavailableHandler) : base(null)
+        {
+            var policy = new AccessConnectionPoolPolicy
+            {
+                _pool = this,
+                Name = name
+            };
+            this.Policy = policy;
+            policy.ConnectionString = connectionString;
+
+            this.availableHandler = availableHandler;
+            this.unavailableHandler = unavailableHandler;
+        }
+
+        public void Return(Object<DbConnection> obj, Exception exception, bool isRecreate = false)
+        {
+            if (exception != null && exception is OleDbException)
+            {
+
+                if (obj.Value.Ping() == false)
+                {
+
+                    base.SetUnavailable(exception);
+                }
+            }
+            base.Return(obj, isRecreate);
+        }
+    }
+
+    class AccessConnectionPoolPolicy : IPolicy<DbConnection>
+    {
+
+        internal MsAccessConnectionPool _pool;
+        public string Name { get; set; } = "Microsoft Access OleDbConnection 对象池";
+        public int PoolSize { get; set; } = 100;
+        public TimeSpan SyncGetTimeout { get; set; } = TimeSpan.FromSeconds(30);
+        public TimeSpan IdleTimeout { get; set; } = TimeSpan.Zero;
+        public int AsyncGetCapacity { get; set; } = 10000;
+        public bool IsThrowGetTimeoutException { get; set; } = true;
+        public int CheckAvailableInterval { get; set; } = 5;
+
+        private string _connectionString;
+        public string ConnectionString
+        {
+            get => _connectionString;
+            set
+            {
+                _connectionString = value ?? "";
+
+                var pattern = @"Max\s*pool\s*size\s*=\s*(\d+)";
+                Match m = Regex.Match(_connectionString, pattern, RegexOptions.IgnoreCase);
+                if (m.Success)
+                {
+                    if (int.TryParse(m.Groups[1].Value, out var poolsize) && poolsize > 0) 
+                        PoolSize = poolsize;
+                    _connectionString = Regex.Replace(_connectionString, pattern, "", RegexOptions.IgnoreCase);
+                }
+
+                pattern = @"Connection\s*LifeTime\s*=\s*(\d+)";
+                m = Regex.Match(_connectionString, pattern, RegexOptions.IgnoreCase);
+                if (m.Success)
+                {
+                    IdleTimeout = TimeSpan.FromSeconds(int.Parse(m.Groups[1].Value));
+                    _connectionString = Regex.Replace(_connectionString, pattern, "", RegexOptions.IgnoreCase);
+                }
+
+                var minPoolSize = 0;
+                pattern = @"Min\s*pool\s*size\s*=\s*(\d+)";
+                m = Regex.Match(_connectionString, pattern, RegexOptions.IgnoreCase);
+                if (m.Success)
+                {
+                    minPoolSize = int.Parse(m.Groups[1].Value);
+                    _connectionString = Regex.Replace(_connectionString, pattern, "", RegexOptions.IgnoreCase);
+                }
+
+                FreeSql.Internal.CommonUtils.PrevReheatConnectionPool(_pool, minPoolSize);
+            }
+        }
+
+        public bool OnCheckAvailable(Object<DbConnection> obj)
+        {
+            if (obj.Value.State == ConnectionState.Closed) obj.Value.Open();
+            return obj.Value.Ping(true);
+        }
+
+        public DbConnection OnCreate()
+        {
+            var conn = new OleDbConnection(_connectionString);
+            return conn;
+        }
+
+        public void OnDestroy(DbConnection obj)
+        {
+            if (obj.State != ConnectionState.Closed) obj.Close();
+            obj.Dispose();
+        }
+
+        public void OnGet(Object<DbConnection> obj)
+        {
+
+            if (_pool.IsAvailable)
+            {
+
+                if (obj.Value == null)
+                {
+                    if (_pool.SetUnavailable(new Exception("连接字符串错误")) == true)
+                        throw new Exception($"【{this.Name}】连接字符串错误，请检查。");
+                    return;
+                }
+
+                if (obj.Value.State != ConnectionState.Open || DateTime.Now.Subtract(obj.LastReturnTime).TotalSeconds > 60 && obj.Value.Ping() == false)
+                {
+
+                    try
+                    {
+                        obj.Value.Open();
+                    }
+                    catch (Exception ex)
+                    {
+                        if (_pool.SetUnavailable(ex) == true)
+                            throw new Exception($"【{this.Name}】状态不可用，等待后台检查程序恢复方可使用。{ex.Message}");
+                    }
+                }
+            }
+        }
+
+#if net40
+#else
+        async public Task OnGetAsync(Object<DbConnection> obj)
+        {
+
+            if (_pool.IsAvailable)
+            {
+
+                if (obj.Value == null)
+                {
+                    if (_pool.SetUnavailable(new Exception("连接字符串错误")) == true)
+                        throw new Exception($"【{this.Name}】连接字符串错误，请检查。");
+                    return;
+                }
+
+                if (obj.Value.State != ConnectionState.Open || DateTime.Now.Subtract(obj.LastReturnTime).TotalSeconds > 60 && (await obj.Value.PingAsync()) == false)
+                {
+
+                    try
+                    {
+                        await obj.Value.OpenAsync();
+                    }
+                    catch (Exception ex)
+                    {
+                        if (_pool.SetUnavailable(ex) == true)
+                            throw new Exception($"【{this.Name}】状态不可用，等待后台检查程序恢复方可使用。{ex.Message}");
+                    }
+                }
+            }
+        }
+#endif
+
+        public void OnGetTimeout()
+        {
+
+        }
+
+        public void OnReturn(Object<DbConnection> obj)
+        {
+            if (obj.Value.State != ConnectionState.Closed) try { obj.Value.Close(); } catch { }
+        }
+
+        public void OnAvailable()
+        {
+            _pool.availableHandler?.Invoke();
+        }
+
+        public void OnUnavailable()
+        {
+            _pool.unavailableHandler?.Invoke();
+        }
+    }
+
+    static class DbConnectionExtensions
+    {
+
+        static DbCommand PingCommand(DbConnection conn)
+        {
+            var cmd = conn.CreateCommand();
+            cmd.CommandTimeout = 5;
+            cmd.CommandText = "select 1";
+            return cmd;
+        }
+        public static bool Ping(this DbConnection that, bool isThrow = false)
+        {
+            try
+            {
+                PingCommand(that).ExecuteNonQuery();
+                return true;
+            }
+            catch
+            {
+                if (that.State != ConnectionState.Closed) try { that.Close(); } catch { }
+                if (isThrow) throw;
+                return false;
+            }
+        }
+
+#if net40
+#else
+        async public static Task<bool> PingAsync(this DbConnection that, bool isThrow = false)
+        {
+            try
+            {
+                await PingCommand(that).ExecuteNonQueryAsync();
+                return true;
+            }
+            catch
+            {
+                if (that.State != ConnectionState.Closed) try { that.Close(); } catch { }
+                if (isThrow) throw;
+                return false;
+            }
+        }
+#endif
+    }
+}