Add log4net logging adapter.

Author: bgrainger

MySqlConnector.sln

@@ -1,6 +1,6 @@
 Microsoft Visual Studio Solution File, Format Version 12.00
 # Visual Studio 15
-VisualStudioVersion = 15.0.27004.2009
+VisualStudioVersion = 15.0.27004.2010
 MinimumVisualStudioVersion = 10.0.40219.1
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "MySqlConnector", "src\MySqlConnector\MySqlConnector.csproj", "{F82378AF-274E-4FBA-8E45-27126D607B85}"
 EndProject
@@ -12,6 +12,8 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "MySqlConnector.Performance"
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Conformance.Tests", "tests\Conformance.Tests\Conformance.Tests.csproj", "{CC0DA702-43E8-471E-9320-F36685C540A1}"
 EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "MySqlConnector.Logging.log4net", "src\MySqlConnector.Logging.log4net\MySqlConnector.Logging.log4net.csproj", "{A15647B8-FA3F-4536-BF4E-4F93F2FBFC75}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -38,6 +40,10 @@ Global
 		{CC0DA702-43E8-471E-9320-F36685C540A1}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{CC0DA702-43E8-471E-9320-F36685C540A1}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{CC0DA702-43E8-471E-9320-F36685C540A1}.Release|Any CPU.Build.0 = Release|Any CPU
+		{A15647B8-FA3F-4536-BF4E-4F93F2FBFC75}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{A15647B8-FA3F-4536-BF4E-4F93F2FBFC75}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{A15647B8-FA3F-4536-BF4E-4F93F2FBFC75}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{A15647B8-FA3F-4536-BF4E-4F93F2FBFC75}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

src/MySqlConnector.Logging.log4net/Log4netLoggerProvider.cs

@@ -0,0 +1,54 @@
+using System;
+using System.Globalization;
+using System.Reflection;
+using log4net;
+using log4net.Core;
+
+namespace MySqlConnector.Logging
+{
+    public sealed class Log4netLoggerProvider : IMySqlConnectorLoggerProvider
+    {
+		public IMySqlConnectorLogger CreateLogger(string name) => new Log4netLogger(LogManager.GetLogger(s_loggerAssembly, "MySqlConnector." + name));
+
+		static readonly Assembly s_loggerAssembly = typeof(Log4netLogger).GetTypeInfo().Assembly;
+		static readonly Type s_loggerType = typeof(Log4netLogger);
+
+		private class Log4netLogger : IMySqlConnectorLogger
+		{
+			public Log4netLogger(ILoggerWrapper log) => m_logger = log.Logger;
+
+			public bool IsEnabled(MySqlConnectorLogLevel level) => m_logger.IsEnabledFor(GetLevel(level));
+
+			public void Log(MySqlConnectorLogLevel level, string message, object[] args = null, Exception exception = null)
+			{
+				if (args == null || args.Length == 0)
+					m_logger.Log(s_loggerType, GetLevel(level), message, exception);
+				else
+					m_logger.Log(s_loggerType, GetLevel(level), string.Format(CultureInfo.InvariantCulture, message, args), exception);
+			}
+
+			private static Level GetLevel(MySqlConnectorLogLevel level)
+			{
+				switch (level)
+				{
+				case MySqlConnectorLogLevel.Trace:
+					return Level.Trace;
+				case MySqlConnectorLogLevel.Debug:
+					return Level.Debug;
+				case MySqlConnectorLogLevel.Info:
+					return Level.Info;
+				case MySqlConnectorLogLevel.Warn:
+					return Level.Warn;
+				case MySqlConnectorLogLevel.Error:
+					return Level.Error;
+				case MySqlConnectorLogLevel.Fatal:
+					return Level.Fatal;
+				default:
+					throw new ArgumentOutOfRangeException(nameof(level), level, "Invalid value for 'level'.");
+				}
+			}
+
+			readonly ILogger m_logger;
+		}
+	}
+}

src/MySqlConnector.Logging.log4net/MySqlConnector.Logging.log4net.csproj

@@ -0,0 +1,19 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFrameworks>net45;net46;netstandard1.3;netstandard2.0</TargetFrameworks>
+    <Title>MySQL Connector Logging Adapter for log4net</Title>
+    <Copyright>Copyright 2017 Bradley Grainger</Copyright>
+    <Authors>Bradley Grainger</Authors>
+    <PackageTags>mysql;mysqlconnector;async;ado.net;database;netcore</PackageTags>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="log4net" Version="2.0.8" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\MySqlConnector\MySqlConnector.csproj" />
+  </ItemGroup>
+
+</Project>