apewer-dotnet/Apewer.Source/Externals/MySql.Data-6.9.11/MySqlClient/Interceptors/CommandInterceptor.cs

#if MYSQL_6_9

// Copyright © 2004, 2011, Oracle and/or its affiliates. All rights reserved.
//
// MySQL Connector/NET is licensed under the terms of the GPLv2
// <http://www.gnu.org/licenses/old-licenses/gpl-2.0.html>, like most 
// MySQL Connectors. There are special exceptions to the terms and 
// conditions of the GPLv2 as it is applied to this software, see the 
// FLOSS License Exception
// <http://www.mysql.com/about/legal/licensing/foss-exception.html>.
//
// This program is free software; you can redistribute it and/or modify 
// it under the terms of the GNU General Public License as published 
// by the Free Software Foundation; version 2 of the License.
//
// This program is distributed in the hope that it will be useful, but 
// WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
// or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 
// for more details.
//
// You should have received a copy of the GNU General Public License along 
// with this program; if not, write to the Free Software Foundation, Inc., 
// 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA

using System;
using System.Collections.Generic;
using System.Text;
using System.Reflection;
using Externals.MySql.Data.MySqlClient.Properties;
using System.Data.Common;
using System.Data;

namespace Externals.MySql.Data.MySqlClient
{
    /// <summary>
    /// BaseCommandInterceptor is the base class that should be used for all userland 
    /// command interceptors
    /// </summary>
    internal abstract class BaseCommandInterceptor
    {
        protected MySqlConnection ActiveConnection { get; private set; }

        public virtual bool ExecuteScalar(string sql, ref object returnValue)
        {
            return false;
        }

        public virtual bool ExecuteNonQuery(string sql, ref int returnValue)
        {
            return false;
        }

        public virtual bool ExecuteReader(string sql, CommandBehavior behavior, ref MySqlDataReader returnValue)
        {
            return false;
        }

        public virtual void Init(MySqlConnection connection)
        {
            ActiveConnection = connection;
        }
    }

    /// <summary>
    /// CommandInterceptor is the "manager" class that keeps the list of registered interceptors
    /// for the given connection.
    /// </summary>
    internal sealed class CommandInterceptor : Interceptor
    {
        bool insideInterceptor = false;
        List<BaseCommandInterceptor> interceptors = new List<BaseCommandInterceptor>();

        public CommandInterceptor(MySqlConnection connection)
        {
            this.connection = connection;

            LoadInterceptors(connection.Settings.CommandInterceptors);
        }

        public bool ExecuteScalar(string sql, ref object returnValue)
        {
            if (insideInterceptor) return false;
            insideInterceptor = true;

            bool handled = false;

            foreach (BaseCommandInterceptor bci in interceptors)
                handled |= bci.ExecuteScalar(sql, ref returnValue);

            insideInterceptor = false;
            return handled;
        }

        public bool ExecuteNonQuery(string sql, ref int returnValue)
        {
            if (insideInterceptor) return false;
            insideInterceptor = true;

            bool handled = false;

            foreach (BaseCommandInterceptor bci in interceptors)
                handled |= bci.ExecuteNonQuery(sql, ref returnValue);

            insideInterceptor = false;
            return handled;
        }

        public bool ExecuteReader(string sql, CommandBehavior behavior, ref MySqlDataReader returnValue)
        {
            if (insideInterceptor) return false;
            insideInterceptor = true;

            bool handled = false;

            foreach (BaseCommandInterceptor bci in interceptors)
                handled |= bci.ExecuteReader(sql, behavior, ref returnValue);

            insideInterceptor = false;
            return handled;
        }

        protected override void AddInterceptor(object o)
        {
            if (o == null)
                throw new ArgumentException(String.Format("Unable to instantiate CommandInterceptor"));

            if (!(o is BaseCommandInterceptor))
                throw new InvalidOperationException(String.Format(Resources.TypeIsNotCommandInterceptor, o.GetType()));
            BaseCommandInterceptor ie = o as BaseCommandInterceptor;
            ie.Init(connection);
            interceptors.Insert(0, (BaseCommandInterceptor)o);
        }

        protected override string ResolveType(string nameOrType)
        {
            if (MySqlConfiguration.Settings != null && MySqlConfiguration.Settings.CommandInterceptors != null)
            {
                foreach (InterceptorConfigurationElement e in MySqlConfiguration.Settings.CommandInterceptors)
                    if (String.Compare(e.Name, nameOrType, true) == 0)
                        return e.Type;
            }
            return base.ResolveType(nameOrType);
        }

    }

}


#endif