[VOL-4291] Rw-core updates for gRPC migration
Change-Id: I8d5a554409115b29318089671ca4e1ab3fa98810
diff --git a/vendor/github.com/coreos/etcd/etcdserver/stats/queue.go b/vendor/github.com/coreos/etcd/etcdserver/stats/queue.go
new file mode 100644
index 0000000..635074c
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/etcdserver/stats/queue.go
@@ -0,0 +1,110 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package stats
+
+import (
+ "sync"
+ "time"
+)
+
+const (
+ queueCapacity = 200
+)
+
+// RequestStats represent the stats for a request.
+// It encapsulates the sending time and the size of the request.
+type RequestStats struct {
+ SendingTime time.Time
+ Size int
+}
+
+type statsQueue struct {
+ items [queueCapacity]*RequestStats
+ size int
+ front int
+ back int
+ totalReqSize int
+ rwl sync.RWMutex
+}
+
+func (q *statsQueue) Len() int {
+ return q.size
+}
+
+func (q *statsQueue) ReqSize() int {
+ return q.totalReqSize
+}
+
+// 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() (*RequestStats, *RequestStats) {
+ 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 RequestStats into the queue and update the records
+func (q *statsQueue) Insert(p *RequestStats) {
+ q.rwl.Lock()
+ defer q.rwl.Unlock()
+
+ q.back = (q.back + 1) % queueCapacity
+
+ if q.size == queueCapacity { //dequeue
+ q.totalReqSize -= q.items[q.front].Size
+ q.front = (q.back + 1) % queueCapacity
+ } else {
+ q.size++
+ }
+
+ q.items[q.back] = p
+ q.totalReqSize += 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.Since(back.SendingTime) > time.Second {
+ q.Clear()
+ return 0, 0
+ }
+
+ sampleDuration := back.SendingTime.Sub(front.SendingTime)
+
+ pr := float64(q.Len()) / float64(sampleDuration) * float64(time.Second)
+
+ br := float64(q.ReqSize()) / 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.totalReqSize = 0
+}