BepInEx/BepInEx.Core/Logging/HarmonyLogSource.cs

using System;
using System.Collections.Generic;
using BepInEx.Configuration;
using HarmonyLogger = HarmonyLib.Tools.Logger;

namespace BepInEx.Logging
{
    public class HarmonyLogSource : ILogSource
    {
        private static readonly ConfigEntry<HarmonyLogger.LogChannel> LogChannels = ConfigFile.CoreConfig.Bind(
         "Harmony.Logger",
         "LogChannels",
         HarmonyLogger.LogChannel.Warn | HarmonyLogger.LogChannel.Error,
         "Specifies which Harmony log channels to listen to.\nNOTE: IL channel dumps the whole patch methods, use only when needed!");

        private static readonly Dictionary<HarmonyLogger.LogChannel, LogLevel> LevelMap = new()
        {
            [HarmonyLogger.LogChannel.Info] = LogLevel.Info,
            [HarmonyLogger.LogChannel.Warn] = LogLevel.Warning,
            [HarmonyLogger.LogChannel.Error] = LogLevel.Error,
            [HarmonyLogger.LogChannel.IL] = LogLevel.Debug
        };

        public HarmonyLogSource()
        {
            HarmonyLogger.ChannelFilter = LogChannels.Value;
            HarmonyLogger.MessageReceived += HandleHarmonyMessage;
        }

        public void Dispose() => HarmonyLogger.MessageReceived -= HandleHarmonyMessage;

        public string SourceName { get; } = "HarmonyX";
        public event EventHandler<LogEventArgs> LogEvent;

        private void HandleHarmonyMessage(object sender, HarmonyLogger.LogEventArgs e)
        {
            if (!LevelMap.TryGetValue(e.LogChannel, out var level))
                return;

            LogEvent?.Invoke(this, new LogEventArgs(e.Message, level, this));
        }
    }
}