Logger and Configuration Refactoring (#573)

* Logging: Refactor log targets into Ryujinx.Common

* Logger: Implement JSON Log Target

* Logger: Optimize Console/File logging targets

Implement a simple ObjectPool to pool up StringBuilders to avoid causing excessive GCing of gen1/2 items when large amounts of log entries are being generated.

We can also pre-determine the async overflow action at initialization time, allowing for an easy optimization in the message enqueue function, avoiding a number of comparisons.

* Logger: Implement LogFormatters

* Config: Refactor configuration file and loading

* Config: Rename to .jsonc to avoid highlighting issues in VSC and GitHub

* Resolve style nits

* Config: Resolve incorrect default key binding

* Config: Also update key binding default in schema

* Tidy up namespace imports

* Config: Update CONFIG.md to reflect new Config file

5 files changed, 204 insertions, 0 deletions

diff --git a/Ryujinx.Common/Logging/Targets/AsyncLogTargetWrapper.cs b/Ryujinx.Common/Logging/Targets/AsyncLogTargetWrapper.cs
new file mode 100644
index 00000000..a805a83b
--- /dev/null
+++ b/Ryujinx.Common/Logging/Targets/AsyncLogTargetWrapper.cs
@@ -0,0 +1,76 @@
+using System;
+using System.Collections.Concurrent;
+using System.Threading;
+
+namespace Ryujinx.Common.Logging
+{
+    public enum AsyncLogTargetOverflowAction
+    {
+        /// <summary>
+        /// Block until there's more room in the queue
+        /// </summary>
+        Block = 0,
+
+        /// <summary>
+        /// Discard the overflowing item
+        /// </summary>
+        Discard = 1
+    }
+
+    public class AsyncLogTargetWrapper : ILogTarget
+    {
+        private ILogTarget _target;
+
+        private Thread _messageThread;
+
+        private BlockingCollection<LogEventArgs> _messageQueue;
+
+        private readonly int _overflowTimeout;
+
+        public AsyncLogTargetWrapper(ILogTarget target)
+            : this(target, -1, AsyncLogTargetOverflowAction.Block)
+        { }
+
+        public AsyncLogTargetWrapper(ILogTarget target, int queueLimit, AsyncLogTargetOverflowAction overflowAction)
+        {
+            _target          = target;
+            _messageQueue    = new BlockingCollection<LogEventArgs>(queueLimit);
+            _overflowTimeout = overflowAction == AsyncLogTargetOverflowAction.Block ? -1 : 0;
+
+            _messageThread = new Thread(() => {
+                while (!_messageQueue.IsCompleted)
+                {
+                    try
+                    {
+                        _target.Log(this, _messageQueue.Take());
+                    }
+                    catch (InvalidOperationException)
+                    {
+                        // IOE means that Take() was called on a completed collection.
+                        // Some other thread can call CompleteAdding after we pass the
+                        // IsCompleted check but before we call Take.
+                        // We can simply catch the exception since the loop will break
+                        // on the next iteration.
+                    }
+                }
+            });
+
+            _messageThread.IsBackground = true;
+            _messageThread.Start();
+        }
+
+        public void Log(object sender, LogEventArgs e)
+        {
+            if (!_messageQueue.IsAddingCompleted)
+            {
+                _messageQueue.TryAdd(e, _overflowTimeout);
+            }
+        }
+
+        public void Dispose()
+        {
+            _messageQueue.CompleteAdding();
+            _messageThread.Join();
+        }
+    }
+}
\ No newline at end of file
diff --git a/Ryujinx.Common/Logging/Targets/ConsoleLogTarget.cs b/Ryujinx.Common/Logging/Targets/ConsoleLogTarget.cs
new file mode 100644
index 00000000..871076a4
--- /dev/null
+++ b/Ryujinx.Common/Logging/Targets/ConsoleLogTarget.cs
@@ -0,0 +1,48 @@
+using System;
+using System.Collections.Concurrent;
+
+namespace Ryujinx.Common.Logging
+{
+    public class ConsoleLogTarget : ILogTarget
+    {
+        private static readonly ConcurrentDictionary<LogLevel, ConsoleColor> _logColors;
+
+        private readonly ILogFormatter _formatter;
+
+        static ConsoleLogTarget()
+        {
+            _logColors = new ConcurrentDictionary<LogLevel, ConsoleColor> {
+                [ LogLevel.Stub    ] = ConsoleColor.DarkGray,
+                [ LogLevel.Info    ] = ConsoleColor.White,
+                [ LogLevel.Warning ] = ConsoleColor.Yellow,
+                [ LogLevel.Error   ] = ConsoleColor.Red
+            };
+        }
+
+        public ConsoleLogTarget()
+        {
+            _formatter = new DefaultLogFormatter();
+        }
+
+        public void Log(object sender, LogEventArgs args)
+        {
+            if (_logColors.TryGetValue(args.Level, out ConsoleColor color))
+            {
+                Console.ForegroundColor = color;
+
+                Console.WriteLine(_formatter.Format(args));
+
+                Console.ResetColor();
+            }
+            else
+            {
+                Console.WriteLine(_formatter.Format(args));
+            }
+        }
+
+        public void Dispose()
+        {
+            Console.ResetColor();
+        }
+    }
+}
diff --git a/Ryujinx.Common/Logging/Targets/FileLogTarget.cs b/Ryujinx.Common/Logging/Targets/FileLogTarget.cs
new file mode 100644
index 00000000..85dc8249
--- /dev/null
+++ b/Ryujinx.Common/Logging/Targets/FileLogTarget.cs
@@ -0,0 +1,36 @@
+using System.IO;
+using System.Text;
+
+namespace Ryujinx.Common.Logging
+{
+    public class FileLogTarget : ILogTarget
+    {
+        private static readonly ObjectPool<StringBuilder> _stringBuilderPool = SharedPools.Default<StringBuilder>();
+
+        private readonly StreamWriter  _logWriter;
+        private readonly ILogFormatter _formatter;
+
+        public FileLogTarget(string path)
+            : this(path, FileShare.Read, FileMode.Append)
+        { }
+
+        public FileLogTarget(string path, FileShare fileShare, FileMode fileMode)
+        {
+            _logWriter = new StreamWriter(File.Open(path, fileMode, FileAccess.Write, fileShare));
+            _formatter = new DefaultLogFormatter();
+        }
+
+        public void Log(object sender, LogEventArgs args)
+        {
+            _logWriter.WriteLine(_formatter.Format(args));
+            _logWriter.Flush();
+        }
+
+        public void Dispose()
+        {
+            _logWriter.WriteLine("---- End of Log ----");
+            _logWriter.Flush();
+            _logWriter.Dispose();
+        }
+    }
+}
diff --git a/Ryujinx.Common/Logging/Targets/ILogTarget.cs b/Ryujinx.Common/Logging/Targets/ILogTarget.cs
new file mode 100644
index 00000000..261c5e64
--- /dev/null
+++ b/Ryujinx.Common/Logging/Targets/ILogTarget.cs
@@ -0,0 +1,9 @@
+using System;
+
+namespace Ryujinx.Common.Logging
+{
+    public interface ILogTarget : IDisposable
+    {
+        void Log(object sender, LogEventArgs args);
+    }
+}
diff --git a/Ryujinx.Common/Logging/Targets/JsonLogTarget.cs b/Ryujinx.Common/Logging/Targets/JsonLogTarget.cs
new file mode 100644
index 00000000..410394aa
--- /dev/null
+++ b/Ryujinx.Common/Logging/Targets/JsonLogTarget.cs
@@ -0,0 +1,35 @@
+using System.IO;
+using Utf8Json;
+
+namespace Ryujinx.Common.Logging
+{
+    public class JsonLogTarget : ILogTarget
+    {
+        private Stream _stream;
+        private bool   _leaveOpen;
+
+        public JsonLogTarget(Stream stream)
+        {
+            _stream = stream;
+        }
+
+        public JsonLogTarget(Stream stream, bool leaveOpen)
+        {
+            _stream    = stream;
+            _leaveOpen = leaveOpen;
+        }
+
+        public void Log(object sender, LogEventArgs e)
+        {
+            JsonSerializer.Serialize(_stream, e);
+        }
+
+        public void Dispose()
+        {
+            if (!_leaveOpen)
+            {
+                _stream.Dispose();
+            }
+        }
+    }
+}