osu-framework/osu.Framework/Audio/Sample/Sample.cs

// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
// See the LICENCE file in the repository root for full licence text.

#nullable disable

using System;
using osu.Framework.Bindables;

namespace osu.Framework.Audio.Sample
{
    public abstract class Sample : AudioCollectionManager<SampleChannel>, ISample
    {
        public const int DEFAULT_CONCURRENCY = 2;

        public string Name { get; }

        protected Sample(string name)
        {
            Name = name;
        }

        public abstract double Length { get; }

        public Bindable<int> PlaybackConcurrency { get; } = new Bindable<int>(DEFAULT_CONCURRENCY);

        internal Action<Sample> OnPlay;

        public SampleChannel Play()
        {
            var channel = GetChannel();
            channel.Play();
            return channel;
        }

        public SampleChannel GetChannel()
        {
            ObjectDisposedException.ThrowIf(IsDisposed, this);

            var channel = CreateChannel();
            channel.OnPlay = onPlay;
            return channel;
        }

        private void onPlay(SampleChannel channel)
        {
            AddItem(channel);
            OnPlay?.Invoke(this);
        }

        public override bool IsAlive => base.IsAlive && (!PendingActions.IsEmpty || Items.Count > 0);

        /// <summary>
        /// Creates a unique playback of this <see cref="Sample"/>.
        /// </summary>
        /// <returns>The <see cref="SampleChannel"/> for the playback.</returns>
        protected abstract SampleChannel CreateChannel();

        protected override void ItemRemoved(SampleChannel item)
        {
            base.ItemRemoved(item);

            // SampleChannels are removed when they're no longer playing (see SampleChannel.IsAlive).
            // They need to be disposed at this point when automatic cleanup is requested (the default).

            if (!item.IsDisposed && !item.ManualFree)
            {
                item.Dispose();
                item.Update();
            }
        }
    }
}