Refactor commands.

server/stats_queue.go

@@ -0,0 +1,88 @@
+package server
+
+import (
+	"sync"
+)
+
+const (
+	queueCapacity = 200
+)
+
+type statsQueue struct {
+	items        [queueCapacity]*packageStats
+	size         int
+	front        int
+	back         int
+	totalPkgSize int
+	rwl          sync.RWMutex
+}
+
+func (q *statsQueue) Len() int {
+	return q.size
+}
+
+func (q *statsQueue) PkgSize() int {
+	return q.totalPkgSize
+}
+
+// FrontAndBack gets the front and back elements in the queue
+// We must grab front and back together with the protection of the lock
+func (q *statsQueue) frontAndBack() (*packageStats, *packageStats) {
+	q.rwl.RLock()
+	defer q.rwl.RUnlock()
+	if q.size != 0 {
+		return q.items[q.front], q.items[q.back]
+	}
+	return nil, nil
+}
+
+// Insert function insert a packageStats into the queue and update the records
+func (q *statsQueue) Insert(p *packageStats) {
+	q.rwl.Lock()
+	defer q.rwl.Unlock()
+
+	q.back = (q.back + 1) % queueCapacity
+
+	if q.size == queueCapacity { //dequeue
+		q.totalPkgSize -= q.items[q.front].size
+		q.front = (q.back + 1) % queueCapacity
+	} else {
+		q.size++
+	}
+
+	q.items[q.back] = p
+	q.totalPkgSize += q.items[q.back].size
+
+}
+
+// Rate function returns the package rate and byte rate
+func (q *statsQueue) Rate() (float64, float64) {
+	front, back := q.frontAndBack()
+
+	if front == nil || back == nil {
+		return 0, 0
+	}
+
+	if time.Now().Sub(back.Time()) > time.Second {
+		q.Clear()
+		return 0, 0
+	}
+
+	sampleDuration := back.Time().Sub(front.Time())
+
+	pr := float64(q.Len()) / float64(sampleDuration) * float64(time.Second)
+
+	br := float64(q.PkgSize()) / float64(sampleDuration) * float64(time.Second)
+
+	return pr, br
+}
+
+// Clear function clear up the statsQueue
+func (q *statsQueue) Clear() {
+	q.rwl.Lock()
+	defer q.rwl.Unlock()
+	q.back = -1
+	q.front = 0
+	q.size = 0
+	q.totalPkgSize = 0
+}