feat: smooth speed calculation (#99)

pkg/download/downloader.go

@@ -97,8 +97,9 @@ func (d *Downloader) Setup() error {
 	}
 	d.tasks = tasks
 
-	// 每秒统计一次下载速度
+	// 每个tick统计一次下载速度
 	go func() {
+
 		for !d.closed.Load() {
 			if len(d.tasks) > 0 {
 				for _, task := range d.tasks {
@@ -117,9 +118,7 @@ func (d *Downloader) Setup() error {
 
 						current := task.fetcher.Progress().TotalDownloaded()
 						task.Progress.Used = task.timer.Used()
-						currUsedTime := float64(d.refreshInterval) / 1000
-						currSpeed := int64(float64(current-task.Progress.Downloaded) / currUsedTime)
-						task.Progress.Speed = (task.Progress.Speed + currSpeed) / 2
+						task.Progress.Speed = task.calcSpeed(current-task.Progress.Downloaded, float64(d.refreshInterval)/1000)
 						task.Progress.Downloaded = current
 						d.emit(EventKeyProgress, task)
 
@@ -516,6 +515,7 @@ func (d *Downloader) restoreFetcher(task *Task) error {
 func initTask(task *Task) {
 	task.timer = &util.Timer{}
 	task.lock = &sync.Mutex{}
+	task.speedArr = make([]int64, 0)
 }
 
 var defaultDownloader = NewDownloader(nil)

pkg/download/model.go

@@ -29,6 +29,7 @@ type Task struct {
 	fetcher        fetcher.Fetcher
 	timer          *util.Timer
 	lock           *sync.Mutex
+	speedArr       []int64
 }
 
 func NewTask() *Task {
@@ -54,6 +55,18 @@ func (t *Task) clone() *Task {
 	}
 }
 
+func (t *Task) calcSpeed(downloaded int64, usedTime float64) int64 {
+	t.speedArr = append(t.speedArr, downloaded)
+	if len(t.speedArr) > 6 {
+		t.speedArr = t.speedArr[1:]
+	}
+	var total int64
+	for _, v := range t.speedArr {
+		total += v
+	}
+	return int64(float64(total) / float64(len(t.speedArr)) / usedTime)
+}
+
 type DownloaderConfig struct {
 	Controller    *controller.Controller
 	FetchBuilders []fetcher.FetcherBuilder