OpenTween/ImageCache.cs

   1 // OpenTween - Client of Twitter
   2 // Copyright (c) 2013 kim_upsilon (@kim_upsilon) <https://upsilo.net/~upsilon/>
   3 // All rights reserved.
   4 //
   5 // This file is part of OpenTween.
   6 //
   7 // This program is free software; you can redistribute it and/or modify it
   8 // under the terms of the GNU General Public License as published by the Free
   9 // Software Foundation; either version 3 of the License, or (at your option)
  10 // any later version.
  11 //
  12 // This program is distributed in the hope that it will be useful, but
  13 // WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  14 // or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
  15 // for more details.
  16 //
  17 // You should have received a copy of the GNU General Public License along
  18 // with this program. If not, see <http://www.gnu.org/licenses/>, or write to
  19 // the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
  20 // Boston, MA 02110-1301, USA.
  21
  22 #nullable enable
  23
  24 using System;
  25 using System.Collections.Generic;
  26 using System.Linq;
  27 using System.Net;
  28 using System.Net.Http;
  29 using System.Text;
  30 using System.Threading;
  31 using System.Threading.Tasks;
  32 using System.Xml.Serialization;
  33 using OpenTween.Connection;
  34
  35 namespace OpenTween
  36 {
  37     public class ImageCache : IDisposable
  38     {
  39         /// <summary>
  40         /// キャッシュとして URL と取得した画像を対に保持する辞書
  41         /// </summary>
  42         internal LRUCacheDictionary<string, Task<MemoryImage>> InnerDictionary;
  43
  44         /// <summary>
  45         /// 非同期タスクをキャンセルするためのトークンのもと
  46         /// </summary>
  47         private CancellationTokenSource cancelTokenSource;
  48
  49         /// <summary>
  50         /// オブジェクトが破棄された否か
  51         /// </summary>
  52         private bool disposed = false;
  53
  54         public ImageCache()
  55         {
  56             this.InnerDictionary = new LRUCacheDictionary<string, Task<MemoryImage>>(trimLimit: 300, autoTrimCount: 100);
  57             this.InnerDictionary.CacheRemoved += (s, e) =>
  58             {
  59                 this.CacheRemoveCount++;
  60
  61                 // まだ参照されている場合もあるのでDisposeはファイナライザ任せ
  62                 var task = e.Item.Value;
  63                 _ = AsyncExceptionBoundary.IgnoreException(task);
  64             };
  65
  66             this.cancelTokenSource = new CancellationTokenSource();
  67         }
  68
  69         /// <summary>
  70         /// 保持しているキャッシュの件数
  71         /// </summary>
  72         public long CacheCount
  73             => this.InnerDictionary.Count;
  74
  75         /// <summary>
  76         /// 破棄されたキャッシュの件数
  77         /// </summary>
  78         public int CacheRemoveCount { get; private set; }
  79
  80         /// <summary>
  81         /// 指定された URL にある画像を非同期に取得するメソッド
  82         /// </summary>
  83         /// <param name="address">取得先の URL</param>
  84         /// <param name="force">キャッシュを使用せずに取得する場合は true</param>
  85         /// <returns>非同期に画像を取得するタスク</returns>
  86         public Task<MemoryImage> DownloadImageAsync(string address, bool force = false)
  87         {
  88             var cancelToken = this.cancelTokenSource.Token;
  89
  90             this.InnerDictionary.TryGetValue(address, out var cachedImageTask);
  91
  92             if (cachedImageTask != null && !force)
  93                 return cachedImageTask;
  94
  95             cancelToken.ThrowIfCancellationRequested();
  96
  97             var imageTask = Task.Run(() => this.FetchImageAsync(address, cancelToken));
  98             this.InnerDictionary[address] = imageTask;
  99
 100             return imageTask;
 101         }
 102
 103         private async Task<MemoryImage> FetchImageAsync(string uri, CancellationToken cancelToken)
 104         {
 105             using var response = await Networking.Http.GetAsync(uri, cancelToken)
 106                 .ConfigureAwait(false);
 107
 108             response.EnsureSuccessStatusCode();
 109
 110             using var imageStream = await response.Content.ReadAsStreamAsync()
 111                 .ConfigureAwait(false);
 112
 113             return await MemoryImage.CopyFromStreamAsync(imageStream)
 114                 .ConfigureAwait(false);
 115         }
 116
 117         public MemoryImage? TryGetFromCache(string address)
 118         {
 119             if (!this.InnerDictionary.TryGetValue(address, out var imageTask) ||
 120                 imageTask.Status != TaskStatus.RanToCompletion)
 121                 return null;
 122
 123             return imageTask.Result;
 124         }
 125
 126         public MemoryImage? TryGetLargerOrSameSizeFromCache(string normalUrl, string size)
 127         {
 128             var sizes = new[] { "mini", "normal", "bigger", "original" };
 129             var minimumIndex = sizes.FindIndex(x => x == size);
 130
 131             foreach (var candidateSize in sizes.Skip(minimumIndex))
 132             {
 133                 var imageUrl = Twitter.CreateProfileImageUrl(normalUrl, candidateSize);
 134                 var image = this.TryGetFromCache(imageUrl);
 135                 if (image != null)
 136                     return image;
 137             }
 138
 139             return null;
 140         }
 141
 142         public void CancelAsync()
 143         {
 144             var oldTokenSource = this.cancelTokenSource;
 145             this.cancelTokenSource = new CancellationTokenSource();
 146
 147             oldTokenSource.Cancel();
 148             oldTokenSource.Dispose();
 149         }
 150
 151         protected virtual void Dispose(bool disposing)
 152         {
 153             if (this.disposed) return;
 154
 155             if (disposing)
 156             {
 157                 this.CancelAsync();
 158
 159                 foreach (var (_, task) in this.InnerDictionary)
 160                 {
 161                     if (task.Status == TaskStatus.RanToCompletion)
 162                         task.Result?.Dispose();
 163                 }
 164
 165                 this.InnerDictionary.Clear();
 166                 this.cancelTokenSource.Dispose();
 167             }
 168
 169             this.disposed = true;
 170         }
 171
 172         public void Dispose()
 173         {
 174             this.Dispose(true);
 175             GC.SuppressFinalize(this);
 176         }
 177
 178         ~ImageCache()
 179             => this.Dispose(false);
 180     }
 181 }