apewer-dotnet/Apewer.Source/Externals/MySql.Data-6.10.9/MySqlClient/Interceptors/CommandInterceptor.cs

#if MYSQL_6_10

// Copyright © 2004, 2018, 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.Data;
using Externals.MySql.Data.MySqlClient;


#if NETSTANDARD1_3
namespace Externals.MySql.Data.MySqlClient.Interceptors
#else
namespace Externals.MySql.Data.MySqlClient
#endif
{
    /// <summary>
    /// BaseCommandInterceptor is the base class that should be used for all userland 
    /// command interceptors
    /// </summary>
    internal abstract class BaseCommandInterceptor
    {
        /// <summary>
        /// Gets the active connection.
        /// </summary>
        protected MySqlConnection ActiveConnection { get; private set; }

        /// <summary>
        /// Executes an SQL statements that returns a scalar value such as a calculation.
        /// </summary>
        /// <param name="sql">The SQL statement to execute.</param>
        /// <param name="returnValue">A scalar value that represents the result returned by the execution of the SQL statement.</param>
        /// <returns><c>false</c>.</returns>
        /// <remarks>This method is intended to be overriden.</remarks>
        public virtual bool ExecuteScalar(string sql, ref object returnValue)
        {
            return false;
        }

        /// <summary>
        /// Executes an SQL statement that returns the number of affected rows.
        /// </summary>
        /// <param name="sql">The SQL statement to execute.</param>
        /// <param name="returnValue">The number of affected rows.</param>
        /// <returns><c>false</c>.</returns>
        /// <remarks>This method is intended to be overriden.</remarks>
        public virtual bool ExecuteNonQuery(string sql, ref int returnValue)
        {
            return false;
        }

        /// <summary>
        /// Executes an SQL statement that will return a resultset.
        /// </summary>
        /// <param name="sql">The SQL statement to execute.</param>
        /// <param name="behavior">A value that describes the results of the query and its effect on the database.</param>
        /// <param name="returnValue">A <see cref="MySqlDataReader"/> object containing the result of the statement execution.</param>
        /// <returns><c>false</c>.</returns>
        /// <remarks>This method is intended to be overriden.</remarks>
        public virtual bool ExecuteReader(string sql, CommandBehavior behavior, ref MySqlDataReader returnValue)
        {
            return false;
        }

        /// <summary>
        /// Sets the active connection.
        /// </summary>
        /// <param name="connection">The active connection.</param>
        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 partial class CommandInterceptor : Interceptor
    {
        bool _insideInterceptor = false;
        readonly List<BaseCommandInterceptor> _interceptors = new List<BaseCommandInterceptor>();

        public CommandInterceptor(MySqlConnection connection)
        {
            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("Unable to instantiate CommandInterceptor");

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


        protected override string ResolveType(string nameOrType)
        {
#if NETSTANDARD1_3
      return base.ResolveType(nameOrType);
#else
            if (MySqlConfiguration.Settings == null || MySqlConfiguration.Settings.CommandInterceptors == null)
                return base.ResolveType(nameOrType);
            foreach (InterceptorConfigurationElement e in MySqlConfiguration.Settings.CommandInterceptors)
                if (String.Compare(e.Name, nameOrType, true) == 0)
                    return e.Type;
            return base.ResolveType(nameOrType);
#endif
        }
    }
}

#endif