dev-npgsql/npgsql: Npgsql is the .NET data provider for PostgreSQL.

src/Npgsql/NpgsqlFactory.cs
126 строк6 KB
Shay Rojansky
Remove stack reflection from logging
23 июл 2019, 00:35
23 июл 2019, 00:357cb121b
#region License
// The PostgreSQL License
//
// Copyright (C) 2018 The Npgsql Development Team
//
// Permission to use, copy, modify, and distribute this software and its
// documentation for any purpose, without fee, and without a written
// agreement is hereby granted, provided that the above copyright notice
// and this paragraph and the following two paragraphs appear in all copies.
//
// IN NO EVENT SHALL THE NPGSQL DEVELOPMENT TEAM BE LIABLE TO ANY PARTY
// FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES,
// INCLUDING LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
// DOCUMENTATION, EVEN IF THE NPGSQL DEVELOPMENT TEAM HAS BEEN ADVISED OF
// THE POSSIBILITY OF SUCH DAMAGE.
//
// THE NPGSQL DEVELOPMENT TEAM SPECIFICALLY DISCLAIMS ANY WARRANTIES,
// INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
// AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
// ON AN "AS IS" BASIS, AND THE NPGSQL DEVELOPMENT TEAM HAS NO OBLIGATIONS
// TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
#endregion

using System;
using System.Data.Common;
using System.Reflection;
using JetBrains.Annotations;
using Npgsql.Logging;

namespace Npgsql
{
    /// <summary>
    /// A factory to create instances of various Npgsql objects.
    /// </summary>
    [Serializable]
    public sealed class NpgsqlFactory : DbProviderFactory, IServiceProvider
    {
        static readonly NpgsqlLogger Log = NpgsqlLogManager.CreateLogger(nameof(NpgsqlFactory));

        /// <summary>
        /// Gets an instance of the <see cref="NpgsqlFactory"/>.
        /// This can be used to retrieve strongly typed data objects.
        /// </summary>
        public static readonly NpgsqlFactory Instance = new NpgsqlFactory();

        NpgsqlFactory() {}

        /// <summary>
        /// Returns a strongly typed <see cref="DbCommand"/> instance.
        /// </summary>
        [NotNull] public override DbCommand CreateCommand() => new NpgsqlCommand();

        /// <summary>
        /// Returns a strongly typed <see cref="DbConnection"/> instance.
        /// </summary>
        [NotNull] public override DbConnection CreateConnection() => new NpgsqlConnection();

        /// <summary>
        /// Returns a strongly typed <see cref="DbParameter"/> instance.
        /// </summary>
        [NotNull] public override DbParameter CreateParameter() => new NpgsqlParameter();

        /// <summary>
        /// Returns a strongly typed <see cref="DbConnectionStringBuilder"/> instance.
        /// </summary>
        [NotNull] public override DbConnectionStringBuilder CreateConnectionStringBuilder() => new NpgsqlConnectionStringBuilder();

        /// <summary>
        /// Returns a strongly typed <see cref="DbCommandBuilder"/> instance.
        /// </summary>
        [NotNull] public override DbCommandBuilder CreateCommandBuilder() => new NpgsqlCommandBuilder();

        /// <summary>
        /// Returns a strongly typed <see cref="DbDataAdapter"/> instance.
        /// </summary>
        [NotNull] public override DbDataAdapter CreateDataAdapter() => new NpgsqlDataAdapter();

        #region IServiceProvider Members

        /// <summary>
        /// Gets the service object of the specified type.
        /// </summary>
        /// <param name="serviceType">An object that specifies the type of service object to get.</param>
        /// <returns>A service object of type serviceType, or null if there is no service object of type serviceType.</returns>
        [CanBeNull]
        public object GetService([NotNull] Type serviceType)
        {
            if (serviceType == null)
                throw new ArgumentNullException(nameof(serviceType));

            // In legacy Entity Framework, this is the entry point for obtaining Npgsql's
            // implementation of DbProviderServices. We use reflection for all types to
            // avoid any dependencies on EF stuff in this project. EF6 (and of course EF Core) do not use this method.

            if (serviceType.FullName != "System.Data.Common.DbProviderServices")
                return null;

            // User has requested a legacy EF DbProviderServices implementation. Check our cache first.
            if (_legacyEntityFrameworkServices != null)
                return _legacyEntityFrameworkServices;

            // First time, attempt to find the EntityFramework5.Npgsql assembly and load the type via reflection
            var assemblyName = typeof(NpgsqlFactory).GetTypeInfo().Assembly.GetName();
            assemblyName.Name = "EntityFramework5.Npgsql";
            Assembly npgsqlEfAssembly;
            try {
                npgsqlEfAssembly = Assembly.Load(new AssemblyName(assemblyName.FullName));
            } catch (Exception e) {
                Log.Debug("A service request was made for System.Data.Common.DbProviderServices, but the EntityFramework5.Npgsql assemby could not be loaded.", e);
                return null;
            }

            Type npgsqlServicesType;
            if ((npgsqlServicesType = npgsqlEfAssembly.GetType("Npgsql.NpgsqlServices")) == null ||
                npgsqlServicesType.GetProperty("Instance") == null)
                throw new Exception("EntityFramework5.Npgsql assembly does not seem to contain the correct type!");

            return _legacyEntityFrameworkServices = npgsqlServicesType.GetProperty("Instance", BindingFlags.Public | BindingFlags.Static).GetMethod.Invoke(null, new object[0]);
        }

        [CanBeNull]
        static object _legacyEntityFrameworkServices;

        #endregion
    }
}