protected void QueueImageLoadingTask(IImageLoaderTask task) { if (task.IsCancelled || task.IsCompleted || ExitTasksEarly) { if (!task.IsCompleted) { task.TryDispose(); } return; } IImageLoaderTask similarRunningTask = null; similarRunningTask = PendingTasks.FirstOrDefaultByRawKey(task.KeyRaw); if (similarRunningTask == null) { Interlocked.Increment(ref _statsTotalPending); Enqueue(task); } else { if (task.Parameters.Priority.HasValue && (!similarRunningTask.Parameters.Priority.HasValue || task.Parameters.Priority.Value > similarRunningTask.Parameters.Priority.Value)) { similarRunningTask.Parameters.WithPriority(task.Parameters.Priority.Value); PendingTasks.TryUpdatePriority(similarRunningTask, task.Parameters.Priority.Value); } if (task.Parameters.OnDownloadProgress != null) { var similarTaskOnDownloadProgress = similarRunningTask.Parameters.OnDownloadProgress; similarRunningTask.Parameters.DownloadProgress((DownloadProgress obj) => { similarTaskOnDownloadProgress?.Invoke(obj); task.Parameters.OnDownloadProgress(obj); }); } } if (PauseWork) { return; } if (similarRunningTask == null || !task.CanUseMemoryCache) { TakeFromPendingTasksAndRun(); } else { Interlocked.Increment(ref _statsTotalWaiting); Logger.Debug(string.Format("Wait for similar request for key: {0}", task.Key)); SimilarTasks.Add(task); } }
protected void QueueImageLoadingTask(IImageLoaderTask task) { if (task.IsCancelled || task.IsCompleted || ExitTasksEarly) { if (!task.IsCompleted) { task.TryDispose(); } return; } IImageLoaderTask?similarRunningTask = null; similarRunningTask = PendingTasks.FirstOrDefaultByRawKey(task.KeyRaw); if (similarRunningTask == null) { Interlocked.Increment(ref _statsTotalPending); Enqueue(task); } else { if (task.Priority.HasValue && (!similarRunningTask.Priority.HasValue || task.Priority.Value > similarRunningTask.Priority.Value)) { similarRunningTask.Priority = task.Priority.Value; PendingTasks.TryUpdatePriority(similarRunningTask, task.Priority.Value); } #if LATER similarRunningTask.ImageSource.DownloadProgress += (sender, args) => task.ImageSource.RaiseDownloadProgress(args); #endif } if (PauseWork) { return; } if (similarRunningTask == null || !task.CanUseMemoryCache) { TakeFromPendingTasksAndRun(); } else { Interlocked.Increment(ref _statsTotalWaiting); _imageLoader.Logger?.Debug($"Wait for similar request for key: {task.Key}"); SimilarTasks.Add(task); } }
protected async Task TakeFromPendingTasksAndRunAsync() { if (PendingTasks.Count == 0) { return; } Dictionary <string, IImageLoaderTask> tasksToRun = null; int preloadOrUrlTasksCount = 0; int urlTasksCount = 0; int preloadTasksCount = 0; lock (_lock) { if (RunningTasks.Count >= MaxParallelTasks) { urlTasksCount = RunningTasks.Count(v => v.Value != null && (!v.Value.Parameters.Preload && v.Value.Parameters.Source == ImageSource.Url)); preloadTasksCount = RunningTasks.Count(v => v.Value != null && v.Value.Parameters.Preload); preloadOrUrlTasksCount = preloadTasksCount + urlTasksCount; if (preloadOrUrlTasksCount == 0 || preloadOrUrlTasksCount != MaxParallelTasks) { return; } // Allow only half of MaxParallelTasks as additional allowed tasks when preloading occurs to prevent starvation if (RunningTasks.Count - Math.Max(1, Math.Min(preloadOrUrlTasksCount, MaxParallelTasks / 2)) >= MaxParallelTasks) { return; } } int numberOfTasks = MaxParallelTasks - RunningTasks.Count + Math.Min(preloadOrUrlTasksCount, MaxParallelTasks / 2); tasksToRun = new Dictionary <string, IImageLoaderTask>(); IImageLoaderTask task = null; while (tasksToRun.Count < numberOfTasks && PendingTasks.TryDequeue(out task)) { if (task == null || task.IsCancelled || task.IsCompleted) { continue; } // We don't want to load, at the same time, images that have same key or same raw key at the same time // This way we prevent concurrent downloads and benefit from caches string rawKey = task.KeyRaw; if (RunningTasks.ContainsKey(rawKey) || tasksToRun.ContainsKey(rawKey)) { SimilarTasks.Add(task); continue; } if (preloadOrUrlTasksCount != 0) { if (!task.Parameters.Preload && (urlTasksCount == 0 || task.Parameters.Source != ImageSource.Url)) { tasksToRun.Add(rawKey, task); } else { Enqueue(task); break; } } else { tasksToRun.Add(rawKey, task); } } foreach (var item in tasksToRun) { RunningTasks.Add(item.Key, item.Value); Interlocked.Increment(ref _statsTotalRunning); } } if (tasksToRun != null && tasksToRun.Count > 0) { var tasks = tasksToRun.Select(p => RunImageLoadingTaskAsync(p.Value)); await Task.WhenAll(tasks).ConfigureAwait(false); } }
protected async Task TakeFromPendingTasksAndRunAsync() { if (PendingTasks.Count == 0) { return; } Dictionary <string, IImageLoaderTask>?tasksToRun = null; int urlTasksCount = 0; lock (_lock) { if (RunningTasks.Count >= MaxParallelTasks) { urlTasksCount = RunningTasks.Count(v => v.Value != null && v.Value.ImageSource.Source is UriSource); if (urlTasksCount == 0 || urlTasksCount != MaxParallelTasks) { return; } // Allow only half of MaxParallelTasks as additional allowed tasks when preloading occurs to prevent starvation if (RunningTasks.Count - Math.Max(1, Math.Min(urlTasksCount, MaxParallelTasks / 2)) >= MaxParallelTasks) { return; } } int numberOfTasks = MaxParallelTasks - RunningTasks.Count + Math.Min(urlTasksCount, MaxParallelTasks / 2); tasksToRun = new Dictionary <string, IImageLoaderTask>(); while (tasksToRun.Count < numberOfTasks && PendingTasks.TryDequeue(out IImageLoaderTask? task)) { if (task == null || task.IsCancelled || task.IsCompleted) { continue; } // We don't want to load, at the same time, images that have same key or same raw key at the same time // This way we prevent concurrent downloads and benefit from caches string rawKey = task.KeyRaw; if (RunningTasks.ContainsKey(rawKey) || tasksToRun.ContainsKey(rawKey)) { SimilarTasks.Add(task); continue; } if (urlTasksCount != 0) { if (!(task.ImageSource.Source is UriSource)) { tasksToRun.Add(rawKey, task); } else { Enqueue(task); break; } } else { tasksToRun.Add(rawKey, task); } } foreach (var item in tasksToRun) { RunningTasks.Add(item.Key, item.Value); Interlocked.Increment(ref _statsTotalRunning); } } if (tasksToRun != null && tasksToRun.Count > 0) { var tasks = tasksToRun.Select(async p => { await Task.Factory.StartNew(async() => { try { await RunImageLoadingTaskAsync(p.Value).ConfigureAwait(false); } catch (Exception ex) { _imageLoader.Logger?.Error("TakeFromPendingTasksAndRun exception", ex); } }, CancellationToken.None, TaskCreationOptions.PreferFairness | TaskCreationOptions.DenyChildAttach | TaskCreationOptions.HideScheduler, TaskScheduler.Default).ConfigureAwait(false); }); await Task.WhenAll(tasks).ConfigureAwait(false); } }