feature: Add NLog logging adapter (#236)

src/Splat.NLog/MutableDependencyResolverExtensions.cs

@@ -0,0 +1,39 @@
+// Copyright (c) 2019 .NET Foundation and Contributors. All rights reserved.
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for full license information.
+
+namespace Splat.NLog
+{
+    /// <summary>
+    /// NLog specific extensions for the Mutable Dependency Resolver.
+    /// </summary>
+    public static class MutableDependencyResolverExtensions
+    {
+        /// <summary>
+        /// Simple helper to initialize NLog within Splat with the Wrapping Full Logger.
+        /// </summary>
+        /// <remarks>
+        /// You should configure NLog prior to calling this method.
+        /// </remarks>
+        /// <param name="instance">
+        /// An instance of Mutable Dependency Resolver.
+        /// </param>
+        /// <example>
+        /// <code>
+        /// Locator.CurrentMutable.UseNLogWithWrappingFullLogger();
+        /// </code>
+        /// </example>
+        public static void UseNLogWithWrappingFullLogger(this IMutableDependencyResolver instance)
+        {
+            var funcLogManager = new FuncLogManager(type =>
+            {
+                var actualLogger = global::NLog.LogManager.GetLogger(type.ToString());
+                var miniLoggingWrapper = new NLogLogger(actualLogger);
+                return new WrappingFullLogger(miniLoggingWrapper);
+            });
+
+            instance.RegisterConstant(funcLogManager, typeof(ILogManager));
+        }
+    }
+}

src/Splat.NLog/NLogLogger.cs

@@ -0,0 +1,78 @@
+// Copyright (c) 2019 .NET Foundation and Contributors. All rights reserved.
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for full license information.
+
+using System;
+using System.Diagnostics;
+using System.Linq;
+using System.Reflection;
+using NLog;
+
+namespace Splat.NLog
+{
+    /// <summary>
+    /// NLog Logger taken from ReactiveUI 5.
+    /// </summary>
+    [DebuggerDisplay("Name={_inner.Name} Level={Level}")]
+    public sealed class NLogLogger : ILogger
+    {
+        private readonly global::NLog.ILogger _inner;
+        private LogLevel _level;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="NLogLogger"/> class.
+        /// </summary>
+        /// <param name="inner">The actual nlog logger.</param>
+        /// <exception cref="ArgumentNullException">NLog logger not passed.</exception>
+        public NLogLogger(global::NLog.ILogger inner)
+        {
+            _inner = inner ?? throw new ArgumentNullException(nameof(inner));
+        }
+
+        /// <inheritdoc />
+        public LogLevel Level
+        {
+            get => _level;
+
+            set
+            {
+                // would it be better for ILogger to have a readonly property?
+                // rather than a rather blunt way to adjust the level?
+                // another considerationwas i didn't want to add a dependency on System.Reactive
+                // up to you
+                _level = value;
+                foreach (var configurationLoggingRule in _inner.Factory.Configuration.LoggingRules)
+                {
+                    configurationLoggingRule.SetLoggingLevels(SplatLogLevelToNLogLevel(value), global::NLog.LogLevel.Fatal);
+                }
+            }
+        }
+
+        /// <inheritdoc />
+        public void Write(string message, LogLevel logLevel)
+        {
+            _inner.Log(SplatLogLevelToNLogLevel(logLevel), message);
+        }
+
+        /// <inheritdoc />
+        public void Write(string message, Type type, LogLevel logLevel)
+        {
+            _inner.Log(SplatLogLevelToNLogLevel(logLevel), $"{type.Name}: {message}");
+        }
+
+        private static global::NLog.LogLevel SplatLogLevelToNLogLevel(LogLevel logLevel)
+        {
+            var mappings = new[]
+                               {
+                                   new Tuple<LogLevel, global::NLog.LogLevel>(LogLevel.Debug, global::NLog.LogLevel.Debug),
+                                   new Tuple<LogLevel, global::NLog.LogLevel>(LogLevel.Info, global::NLog.LogLevel.Info),
+                                   new Tuple<LogLevel, global::NLog.LogLevel>(LogLevel.Warn, global::NLog.LogLevel.Warn),
+                                   new Tuple<LogLevel, global::NLog.LogLevel>(LogLevel.Error, global::NLog.LogLevel.Error),
+                                   new Tuple<LogLevel, global::NLog.LogLevel>(LogLevel.Fatal, global::NLog.LogLevel.Fatal)
+                               };
+
+            return mappings.First(x => x.Item1 == logLevel).Item2;
+        }
+    }
+}

src/Splat.NLog/Splat.NLog.csproj

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+<Project Sdk="MSBuild.Sdk.Extras">
+  <PropertyGroup>
+    <TargetFrameworks>net461;uap10.0.16299;MonoAndroid80;Xamarin.iOS10;netstandard2.0</TargetFrameworks>
+    <!--Xamarin.Mac20; -->
+    <AssemblyName>Splat.NLog</AssemblyName>
+    <RootNamespace>Splat</RootNamespace>
+    <Authors>Paul Betts</Authors>
+    <Description>NLog integrations for Splat</Description>
+    <PackageId>Splat.NLog</PackageId>
+  </PropertyGroup>
+  <ItemGroup>
+    <PackageReference Include="NLog" Version="4.5.0" />
+  </ItemGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\Splat\Splat.csproj" />
+  </ItemGroup>
+</Project>