harmonia/Harmonia.UI/Caching/AudioBitmapCache.cs

using Avalonia.Media.Imaging;
using Harmonia.Core.Caching;
using Harmonia.Core.Imaging;
using Harmonia.Core.Models;
using Microsoft.Extensions.Caching.Memory;
using System;
using System.IO;
using System.Threading;
using System.Threading.Tasks;

namespace Harmonia.UI.Caching;

public class AudioBitmapCache(IAudioImageExtractor audioImageExtractor) : MemoryCache<Song, Bitmap>, IAudioBitmapCache
{
    protected override MemoryCacheOptions Options => new()
    {
        SizeLimit = 40,
        CompactionPercentage = 0.2,
    };

    protected override TimeSpan SlidingExpiration => TimeSpan.FromSeconds(600);

    protected override int MaxConcurrentRequests => 8;

    protected override object? GetKey(Song key)
    {
        if (string.IsNullOrWhiteSpace(key.ImageHash) == false)
        {
            return key.ImageHash;
        }
        else if (string.IsNullOrWhiteSpace(key.ImageName) == false)
        {
            return key.ImageName;
        }

        return null;
    }

    protected override async ValueTask<Bitmap?> FetchAsync(Song key, CancellationToken cancellationToken)
    {
        SongPictureInfo? songPictureInfo = await audioImageExtractor.ExtractImageAsync(key.FileName, cancellationToken);

        if (songPictureInfo == null)
            return null;

        using MemoryStream stream = new(songPictureInfo.Data);

        return new Bitmap(stream);
    }

    protected override long GetEntrySize(Bitmap entry)
    {
        return 1;
    }
}