Audio streaming hangs when OnGetData() is slow

[bastienleonard]

Example:

#include <iostream>

#include <SFML/Audio.hpp>
#include <SFML/Graphics.hpp>


class CustomStream : public sf::SoundStream
{
public:
    CustomStream(const std::string& path)
    {
        sound_buffer.LoadFromFile(path);
        unsigned int channel_count = sound_buffer.GetChannelCount();
        unsigned int sample_rate = sound_buffer.GetSampleRate();
        buffer = sound_buffer.GetSamples();
        Initialize(channel_count, sample_rate);
    }

    virtual bool OnGetData(Chunk& chunk)
    {
        const int BUFFER_SIZE = 4096;
        chunk.Samples = buffer;
        chunk.SampleCount = BUFFER_SIZE;
        buffer += BUFFER_SIZE;
        sf::Sleep(sf::Seconds(5));

        if (buffer > sound_buffer.GetSamples() + sound_buffer.GetSampleCount())
        {
            chunk.SampleCount = sound_buffer.GetSampleCount() % BUFFER_SIZE;
            return false;
        }

        return true;
    }

    virtual void OnSeek(sf::Time time_offset)
    {
        std::cout << "Time offset: " << time_offset.AsMilliseconds() << '\n';
    }

private:
    sf::SoundBuffer sound_buffer;
    const sf::Int16 *buffer;
};


int main()
{
    sf::RenderWindow app(sf::VideoMode(800, 600, 32), "Title");
    app.SetFramerateLimit(60);
    sf::Event event;
    CustomStream stream("music.ogg");
    stream.Play();
    stream.SetPlayingOffset(sf::Milliseconds(0));

    while (app.IsOpen())
    {
        while (app.PollEvent(event))
        {
            switch (event.Type)
            {
            case sf::Event::Closed:
                app.Close();
                break;
            default:
                break;
            }
        }

        app.Clear(sf::Color::White);
        app.Display();
    }

    return 0;
}

Note that the program doesn't hang if stream.SetPlayingOffset(sf::Milliseconds(0)) is removed.
My guess is that when SetPlayingOffset() stops the stream, the call to Thread.Wait() never returns.
However it should return at some point; it's just slow in this case because of sf::Sleep(sf::Seconds(5)).

Platform: GNU/Linux, SFML commit #e7256e3324a196bb1432786c678f195c9ffb982b.

For the record, I encountered this bug while adding streaming to my Python binding.
Currently the API is very slow, and I was wondering why my program hangs when testing seeking with SetPlayingOffset().

[LaurentGomila]

So the program blocks forever right after stream.SetPlayingOffset(sf::Milliseconds(0))?

I can't reproduce it on Windows, the program behaves the same with or without this line. I had to add a std::cout in OnGetData, because with pauses of 5 seconds every 4096 samples, we can hardly hear something and check whether the program runs or not.

[bastienleonard]

Well this is embarassing, I can't reproduce it either. I guess I was too happy to find out why my binding hangs for no reason. :D I often get a segmentation fault when closing the program, however.

[LaurentGomila]

I often get a segmentation fault when closing the program, however

This is probably bug #30.