1 // OpenTween - Client of Twitter
2 // Copyright (c) 2013 kim_upsilon (@kim_upsilon) <https://upsilo.net/~upsilon/>
3 // All rights reserved.
5 // This file is part of OpenTween.
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)
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
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.
25 using System.Collections.Generic;
28 using System.Threading.Tasks;
30 using System.Threading;
31 using System.Xml.Serialization;
32 using System.Net.Http;
33 using OpenTween.Connection;
37 public class ImageCache : IDisposable
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
42 internal LRUCacheDictionary<string, Task<MemoryImage>> innerDictionary;
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
47 private CancellationTokenSource cancelTokenSource;
50 /// innerDictionary の排他制御のためのロックオブジェクト
52 private readonly object lockObject = new object();
57 private bool disposed = false;
61 this.innerDictionary = new LRUCacheDictionary<string, Task<MemoryImage>>(trimLimit: 300, autoTrimCount: 100);
62 this.innerDictionary.CacheRemoved += (s, e) => {
63 // 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
64 this.CacheRemoveCount++;
67 this.cancelTokenSource = new CancellationTokenSource();
73 public long CacheCount
74 => this.innerDictionary.Count;
79 public int CacheRemoveCount { get; private set; }
82 /// 指定された URL にある画像を非同期に取得するメソッド
84 /// <param name="address">取得先の URL</param>
85 /// <param name="force">キャッシュを使用せずに取得する場合は true</param>
86 /// <returns>非同期に画像を取得するタスク</returns>
87 public Task<MemoryImage> DownloadImageAsync(string address, bool force = false)
89 var cancelToken = this.cancelTokenSource.Token;
93 lock (this.lockObject)
95 innerDictionary.TryGetValue(address, out var cachedImageTask);
97 if (cachedImageTask != null)
100 this.innerDictionary.Remove(address);
102 return cachedImageTask;
105 cancelToken.ThrowIfCancellationRequested();
107 var imageTask = this.FetchImageAsync(address, cancelToken);
108 this.innerDictionary[address] = imageTask;
115 private async Task<MemoryImage> FetchImageAsync(string uri, CancellationToken cancelToken)
117 using var response = await Networking.Http.GetAsync(uri, cancelToken)
118 .ConfigureAwait(false);
120 response.EnsureSuccessStatusCode();
122 using var imageStream = await response.Content.ReadAsStreamAsync()
123 .ConfigureAwait(false);
125 return await MemoryImage.CopyFromStreamAsync(imageStream)
126 .ConfigureAwait(false);
129 public MemoryImage? TryGetFromCache(string address)
131 lock (this.lockObject)
133 if (!this.innerDictionary.TryGetValue(address, out var imageTask) ||
134 imageTask.Status != TaskStatus.RanToCompletion)
137 return imageTask.Result;
141 public void CancelAsync()
143 lock (this.lockObject)
145 var oldTokenSource = this.cancelTokenSource;
146 this.cancelTokenSource = new CancellationTokenSource();
148 oldTokenSource.Cancel();
149 oldTokenSource.Dispose();
153 protected virtual void Dispose(bool disposing)
155 if (this.disposed) return;
161 lock (this.lockObject)
163 foreach (var (_, task) in this.innerDictionary)
165 if (task.Status == TaskStatus.RanToCompletion)
166 task.Result?.Dispose();
169 this.innerDictionary.Clear();
170 this.cancelTokenSource.Dispose();
174 this.disposed = true;
177 public void Dispose()
180 GC.SuppressFinalize(this);
184 => this.Dispose(false);