log avalonia warnings and write bledy.txt as it goes

StarterNG/Infrastructure/Diagnostics.cs

@@ -15,6 +15,9 @@ public static class Diagnostics
     private static readonly object Gate = new();
     private static readonly List<string> Lines = new();
 
+    private static StreamWriter? _writer;
+    private static bool _writerFailed;
+
     public static string LogPath =>
         Path.Combine(Directory.GetCurrentDirectory(), "starter", "bledy.txt");
 
@@ -25,13 +28,29 @@ public static class Diagnostics
 
     public static void Clear()
     {
-        lock (Gate) Lines.Clear();
+        lock (Gate)
+        {
+            Lines.Clear();
+            CloseWriter();
+            try
+            {
+                if (File.Exists(LogPath))
+                    File.Delete(LogPath);
+            }
+            catch
+            {
+            }
+        }
     }
 
     public static void Log(string message)
     {
+        string line = $"{DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss", CultureInfo.InvariantCulture)}  {message}";
         lock (Gate)
-            Lines.Add($"{DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss", CultureInfo.InvariantCulture)}  {message}");
+        {
+            Lines.Add(line);
+            Append(line);
+        }
     }
 
     public static void Log(IEnumerable<string> messages)
@@ -45,22 +64,66 @@ public static class Diagnostics
 
     public static void Flush()
     {
-        string[] snapshot;
         lock (Gate)
         {
-            if (Lines.Count == 0) return;
-            snapshot = Lines.ToArray();
+            if (Lines.Count == 0)
+                return;
+
+            try
+            {
+                _writer?.Flush();
+            }
+            catch (Exception ex)
+            {
+                _writerFailed = true;
+                Lines.Add($"log flush failed: {ex.GetType().Name}: {ex.Message}");
+            }
+
+            if (!_writerFailed && _writer is not null)
+                return;
+
+            try
+            {
+                Directory.CreateDirectory(Path.GetDirectoryName(LogPath)!);
+                File.WriteAllLines(LogPath, Lines);
+            }
+            catch
+            {
+            }
         }
+    }
+
+    private static void Append(string line)
+    {
+        if (_writerFailed)
+            return;
 
         try
         {
-            string dir = Path.GetDirectoryName(LogPath)!;
-            Directory.CreateDirectory(dir);
-            File.WriteAllLines(LogPath, snapshot);
+            if (_writer is null)
+            {
+                Directory.CreateDirectory(Path.GetDirectoryName(LogPath)!);
+                _writer = new StreamWriter(LogPath, append: false) { AutoFlush = true };
+            }
+            _writer.WriteLine(line);
+        }
+        catch
+        {
+            _writerFailed = true;
+            CloseWriter();
+        }
+    }
+
+    private static void CloseWriter()
+    {
+        try
+        {
+            _writer?.Dispose();
         }
         catch
         {
         }
+        _writer = null;
     }
 
     private static Window? Owner =>

StarterNG/Infrastructure/DiagnosticsLogSink.cs

@@ -0,0 +1,85 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using Avalonia.Logging;
+
+namespace StarterNG.Infrastructure;
+
+public sealed class DiagnosticsLogSink : ILogSink
+{
+    private const int MaxDistinctMessages = 200;
+
+    private readonly LogEventLevel _minimumLevel;
+    private readonly HashSet<string> _seen = new(StringComparer.Ordinal);
+    private readonly object _gate = new();
+    private bool _capped;
+
+    private DiagnosticsLogSink(LogEventLevel minimumLevel) => _minimumLevel = minimumLevel;
+
+    public static void Install(LogEventLevel minimumLevel = LogEventLevel.Warning) =>
+        Logger.Sink = new DiagnosticsLogSink(minimumLevel);
+
+    public bool IsEnabled(LogEventLevel level, string area) => level >= _minimumLevel;
+
+    public void Log(LogEventLevel level, string area, object? source, string messageTemplate) =>
+        Write(level, area, source, messageTemplate, null);
+
+    public void Log(LogEventLevel level, string area, object? source, string messageTemplate,
+                    params object?[] propertyValues) =>
+        Write(level, area, source, messageTemplate, propertyValues);
+
+    private void Write(LogEventLevel level, string area, object? source, string messageTemplate,
+                       object?[]? propertyValues)
+    {
+        if (!IsEnabled(level, area))
+            return;
+
+        string line = $"[Avalonia/{area}/{level}] {Format(messageTemplate, propertyValues)}";
+        if (source is not null)
+            line += $" (source: {source.GetType().Name})";
+
+        lock (_gate)
+        {
+            if (_capped || !_seen.Add(line))
+                return;
+            if (_seen.Count >= MaxDistinctMessages)
+            {
+                _capped = true;
+                Diagnostics.Log(line);
+                Diagnostics.Log($"[Avalonia] {MaxDistinctMessages} distinct messages logged, muting the rest");
+                return;
+            }
+        }
+
+        Diagnostics.Log(line);
+    }
+
+    private static string Format(string template, object?[]? values)
+    {
+        if (values is null || values.Length == 0 || template.IndexOf('{') < 0)
+            return template;
+
+        var sb = new StringBuilder(template.Length + 32);
+        int next = 0;
+        for (int i = 0; i < template.Length; i++)
+        {
+            if (template[i] != '{')
+            {
+                sb.Append(template[i]);
+                continue;
+            }
+
+            int close = template.IndexOf('}', i);
+            if (close < 0)
+            {
+                sb.Append(template, i, template.Length - i);
+                break;
+            }
+
+            sb.Append(next < values.Length ? values[next]?.ToString() ?? "null" : template[i..(close + 1)]);
+            next++;
+            i = close;
+        }
+        return sb.ToString();
+    }
+}

StarterNG/Program.cs

@@ -5,7 +5,7 @@ using StarterNG.Infrastructure;
 
 namespace StarterNG;
 
-class Program
+static class Program
 {
 
     [STAThread]
@@ -39,9 +39,15 @@ class Program
         }
     }
 
+    private static AppBuilder WithDiagnosticsLogging(this AppBuilder builder)
+    {
+        DiagnosticsLogSink.Install();
+        return builder;
+    }
+
     public static AppBuilder BuildAvaloniaApp()
         => AppBuilder.Configure<App>()
             .UsePlatformDetect()
             .WithInterFont()
-            .LogToTrace();
+            .WithDiagnosticsLogging();
 }