21651055502

Committed 03 Feb 2026 10:55PM UTC coverage: 31.138% (+0.06%) from 31.077%

Build # 21651055502

Build Type

push

coveralls.net

Committed by

DemoBytom

Commit Message

Fix endless hang if an exception is thrown within `MainLoopService`

Previously if an exception was thrown within `DoAsync` it would not propagate outwards in `EngineService` - the task was not marked as faulted within `Task.WhenAll`? Not sure. `Task.Run` with async lambda works.

Run Details

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90.91

/src/Demo.Engine.Core/Services/MainLoopService.cs

// Copyright © Michał Dembski and contributors.
// Distributed under MIT license. See LICENSE file in the root for more information.

using System.Diagnostics;
using Demo.Engine.Core.Features.StaThread;
using Demo.Engine.Core.Interfaces;
using Demo.Engine.Core.Interfaces.Rendering;
using Demo.Engine.Core.Interfaces.Rendering.Shaders;
using Demo.Engine.Core.Requests.Keyboard;
using Demo.Engine.Core.ValueObjects;
using MediatR;
using Microsoft.Extensions.Logging;

namespace Demo.Engine.Core.Services;

internal sealed class MainLoopService
    : IMainLoopService,
      IAsyncDisposable
{
    private readonly ILogger<MainLoopService> _logger;
    private readonly IStaThreadWriter _staThreadWriter;
    private readonly IMediator _mediator;
    private readonly IShaderAsyncCompiler _shaderCompiler;
    private readonly IFpsTimer _fpsTimer;
    private readonly IMainLoopLifetime _mainLoopLifetime;
    private readonly ILoopJob _loopJob;
    private bool _disposedValue;

    public Task ExecutingTask { get; }

    public MainLoopService(
        ILogger<MainLoopService> logger,
        IStaThreadWriter staThreadWriter,
        IMediator mediator,
        IShaderAsyncCompiler shaderCompiler,
        IFpsTimer fpsTimer,
        IRenderingEngine renderingEngine,
        IMainLoopLifetime mainLoopLifetime,
        ILoopJob loopJob)
    {
        _logger = logger;
        _staThreadWriter = staThreadWriter;
        _mediator = mediator;
        _shaderCompiler = shaderCompiler;
        _fpsTimer = fpsTimer;
        _mainLoopLifetime = mainLoopLifetime;
        _loopJob = loopJob;
        ExecutingTask = Task.Run(async () =>
        {
            try
            {
                await DoAsync(renderingEngine);
            }
            catch (Exception ex)
            {
                _logger.LogCritical(ex, "Main loop failed with error! {errorMessage}", ex.Message);
                _mainLoopLifetime.Cancel();
                throw;
            }
        });
    }

    private async Task DoAsync(
        IRenderingEngine renderingEngine)
    {
        _ = await _shaderCompiler.CompileShaders(_mainLoopLifetime.Token);

        var keyboardHandle = await _mediator.Send(new KeyboardHandleRequest(), CancellationToken.None);
        var keyboardCharCache = await _mediator.Send(new KeyboardCharCacheRequest(), CancellationToken.None);

        var surfaces = new RenderingSurfaceId[]
        {
            await _staThreadWriter.CreateSurface(
                _mainLoopLifetime.Token),
            //await _channelWriter.CreateSurface(
            //    _mainLoopLifetime.Token),
        };

        var previous = Stopwatch.GetTimestamp();
        var lag = TimeSpan.Zero;

        var msPerUpdate = TimeSpan.FromSeconds(1) / 60;

        var doEventsOk = true;

        while (
            doEventsOk
            //&& IsRunning
            && !_disposedValue
            && !_mainLoopLifetime.Token.IsCancellationRequested)
        {
            var current = Stopwatch.GetTimestamp();
            var elapsed = Stopwatch.GetElapsedTime(previous, current);
            previous = current;
            lag += elapsed;

            //process input
            // TODO!

            while (lag >= msPerUpdate)
            {
                //Update
                // TODO - fix the UPS timer.. somehow :D
                _fpsTimer.StopUpdateTimer();
                foreach (var renderingSurfaceId in surfaces)
                {
                    if (!renderingEngine.TryGetRenderingSurface(
                        renderingSurfaceId,
                        out var renderingSurface))
                    {
                        _logger.LogCritical(
                            "Rendering surface {id} not found!",
                            renderingSurfaceId);
                        break;
                    }

                    await _loopJob.Update(
                          renderingSurface,
                          keyboardHandle,
                          keyboardCharCache);
                }
                lag -= msPerUpdate;
                _fpsTimer.StartUpdateTimer();
            }

            //Render
            foreach (var renderingSurfaceId in surfaces)
            {
                doEventsOk &= await _staThreadWriter.DoEventsOk(
                    renderingSurfaceId,
                    _mainLoopLifetime.Token);

                using var scope = _fpsTimer.StartRenderingTimerScope(
                    renderingSurfaceId);

                _loopJob.Render(
                    renderingEngine,
                    renderingSurfaceId);
            }
        }
        _mainLoopLifetime.Cancel();
    }

    private async ValueTask Dispose(bool disposing)
    {
        if (!_disposedValue)
        {
            if (disposing)
            {
            }

            _disposedValue = true;
            //Make sure the loop finishes
            await ExecutingTask;
        }
    }

    public async ValueTask DisposeAsync()
    {
        // Do not change this code. Put cleanup code in 'Dispose(bool disposing)' method
        await Dispose(disposing: true);
        GC.SuppressFinalize(this);
    }
}

1	// Copyright © Michał Dembski and contributors.
2	// Distributed under MIT license. See LICENSE file in the root for more information.
3
4	using System.Diagnostics;
5	using Demo.Engine.Core.Features.StaThread;
6	using Demo.Engine.Core.Interfaces;
7	using Demo.Engine.Core.Interfaces.Rendering;
8	using Demo.Engine.Core.Interfaces.Rendering.Shaders;
9	using Demo.Engine.Core.Requests.Keyboard;
10	using Demo.Engine.Core.ValueObjects;
11	using MediatR;
12	using Microsoft.Extensions.Logging;
13
14	namespace Demo.Engine.Core.Services;
15
16	internal sealed class MainLoopService
17	: IMainLoopService,
18	IAsyncDisposable
19	{
20	private readonly ILogger<MainLoopService> _logger;
21	private readonly IStaThreadWriter _staThreadWriter;
22	private readonly IMediator _mediator;
23	private readonly IShaderAsyncCompiler _shaderCompiler;
24	private readonly IFpsTimer _fpsTimer;
25	private readonly IMainLoopLifetime _mainLoopLifetime;
26	private readonly ILoopJob _loopJob;
27	private bool _disposedValue;
28
29	public Task ExecutingTask { get; }	1✔
30
31	public MainLoopService(	1✔
32	ILogger<MainLoopService> logger,	1✔
33	IStaThreadWriter staThreadWriter,	1✔
34	IMediator mediator,	1✔
35	IShaderAsyncCompiler shaderCompiler,	1✔
36	IFpsTimer fpsTimer,	1✔
37	IRenderingEngine renderingEngine,	1✔
38	IMainLoopLifetime mainLoopLifetime,	1✔
39	ILoopJob loopJob)	1✔
40	{
41	_logger = logger;	1✔
42	_staThreadWriter = staThreadWriter;	1✔
43	_mediator = mediator;	1✔
44	_shaderCompiler = shaderCompiler;	1✔
45	_fpsTimer = fpsTimer;	1✔
46	_mainLoopLifetime = mainLoopLifetime;	1✔
47	_loopJob = loopJob;	1✔
48	ExecutingTask = Task.Run(async () =>	1✔
49	{	1✔
50	try	1✔
51	{	1✔
52	await DoAsync(renderingEngine);	1✔
53	}	1✔
54	catch (Exception ex)	×
55	{	1✔
56	_logger.LogCritical(ex, "Main loop failed with error! {errorMessage}", ex.Message);	×
57	_mainLoopLifetime.Cancel();	×
58	throw;	×
59	}	1✔
60	});	1✔
61	}	1✔
62
63	private async Task DoAsync(
64	IRenderingEngine renderingEngine)
65	{
66	_ = await _shaderCompiler.CompileShaders(_mainLoopLifetime.Token);	1✔
67
68	var keyboardHandle = await _mediator.Send(new KeyboardHandleRequest(), CancellationToken.None);	1✔
69	var keyboardCharCache = await _mediator.Send(new KeyboardCharCacheRequest(), CancellationToken.None);	1✔
70
71	var surfaces = new RenderingSurfaceId[]	1✔
72	{	1✔
73	await _staThreadWriter.CreateSurface(	1✔
74	_mainLoopLifetime.Token),	1✔
75	//await _channelWriter.CreateSurface(	1✔
76	// _mainLoopLifetime.Token),	1✔
77	};	1✔
78
79	var previous = Stopwatch.GetTimestamp();	1✔
80	var lag = TimeSpan.Zero;	1✔
81
82	var msPerUpdate = TimeSpan.FromSeconds(1) / 60;	1✔
83
84	var doEventsOk = true;	1✔
85
86	while (	1✔
87	doEventsOk	1✔
88	//&& IsRunning	1✔
89	&& !_disposedValue	1✔
90	&& !_mainLoopLifetime.Token.IsCancellationRequested)	1✔
91	{
92	var current = Stopwatch.GetTimestamp();	1✔
93	var elapsed = Stopwatch.GetElapsedTime(previous, current);	1✔
94	previous = current;	1✔
95	lag += elapsed;	1✔
96
97	//process input
98	// TODO!
99
100	while (lag >= msPerUpdate)	1✔
101	{
102	//Update
103	// TODO - fix the UPS timer.. somehow :D
104	_fpsTimer.StopUpdateTimer();	1✔
105	foreach (var renderingSurfaceId in surfaces)	1✔
106	{
107	if (!renderingEngine.TryGetRenderingSurface(
108	renderingSurfaceId,	1✔
109	out var renderingSurface))	1✔
110	{
111	_logger.LogCritical(	×
112	"Rendering surface {id} not found!",	×
113	renderingSurfaceId);	×
114	break;	×
115	}
116
117	await _loopJob.Update(	1✔
118	renderingSurface,	1✔
119	keyboardHandle,	1✔
120	keyboardCharCache);	1✔
121	}
122	lag -= msPerUpdate;	1✔
123	_fpsTimer.StartUpdateTimer();	1✔
124	}
125
126	//Render
127	foreach (var renderingSurfaceId in surfaces)	1✔
128	{
129	doEventsOk &= await _staThreadWriter.DoEventsOk(	1✔
130	renderingSurfaceId,	1✔
131	_mainLoopLifetime.Token);	1✔
132
133	using var scope = _fpsTimer.StartRenderingTimerScope(	1✔
134	renderingSurfaceId);	1✔
135
136	_loopJob.Render(	1✔
137	renderingEngine,	1✔
138	renderingSurfaceId);	1✔
139	}
140	}
141	_mainLoopLifetime.Cancel();	1✔
142	}	1✔
143
144	private async ValueTask Dispose(bool disposing)
145	{
146	if (!_disposedValue)	1✔
147	{
148	if (disposing)	1✔
149	{
150	}
151
152	_disposedValue = true;	1✔
153	//Make sure the loop finishes
154	await ExecutingTask;	1✔
155	}
156	}	1✔
157
158	public async ValueTask DisposeAsync()
159	{
160	// Do not change this code. Put cleanup code in 'Dispose(bool disposing)' method
161	await Dispose(disposing: true);	1✔
162	GC.SuppressFinalize(this);	1✔
163	}	1✔
164	}

DemoBytom / DemoEngine / 21651055502

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