apewer-dotnet/Apewer.Source/Externals/MySql.Data-6.10.9/MySqlClient/Interceptors/ExceptionInterceptor.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.Linq;
using Externals.MySql.Data.MySqlClient;


namespace Externals.MySql.Data.MySqlClient.Interceptors
{
    /// <summary>
    /// BaseExceptionInterceptor is the base class that should be used for all userland 
    /// exception interceptors.
    /// </summary>
    internal abstract class BaseExceptionInterceptor
    {
        /// <summary>
        /// Returns the received exception.
        /// </summary>
        /// <param name="exception">The exception to be returned.</param>
        /// <returns>The exception originally received.</returns>
        public abstract Exception InterceptException(Exception exception);

        /// <summary>
        /// Gets the active connection.
        /// </summary>
        protected MySqlConnection ActiveConnection { get; private set; }

        /// <summary>
        /// Initilizes this object by setting the active connection.
        /// </summary>
        /// <param name="connection">The connection to become active.</param>
        public virtual void Init(MySqlConnection connection)
        {
            ActiveConnection = connection;
        }
    }

    /// <summary>
    /// StandardExceptionInterceptor is the standard interceptor that simply returns the exception.
    /// It is the default action.
    /// </summary>
    internal sealed class StandardExceptionInterceptor : BaseExceptionInterceptor
    {
        /// <summary>
        /// Returns the received exception, which is the default action
        /// </summary>
        /// <param name="exception">The exception to be returned.</param>
        /// <returns>The exception originally received.</returns>
        public override Exception InterceptException(Exception exception)
        {
            return exception;
        }
    }

    /// <summary>
    /// ExceptionInterceptor is the "manager" class that keeps the list of registered interceptors
    /// for the given connection.
    /// </summary>
    internal sealed class ExceptionInterceptor : Interceptor
    {
        readonly List<BaseExceptionInterceptor> _interceptors = new List<BaseExceptionInterceptor>();

        public ExceptionInterceptor(MySqlConnection connection)
        {
            Connection = connection;

            LoadInterceptors(connection.Settings.ExceptionInterceptors);

            // we always have the standard interceptor
            _interceptors.Add(new StandardExceptionInterceptor());

        }

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

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

        public void Throw(Exception exception)
        {
            Exception e = _interceptors.Aggregate(exception, (current, ie) => ie.InterceptException(current));
            throw e;
        }

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

#endif