Feature: add delay history and improve url-test behavior

common/queue/queue.go

@@ -0,0 +1,71 @@
+package queue
+
+import (
+	"sync"
+)
+
+// Queue is a simple concurrent safe queue
+type Queue struct {
+	items []interface{}
+	lock  sync.RWMutex
+}
+
+// Put add the item to the queue.
+func (q *Queue) Put(items ...interface{}) {
+	if len(items) == 0 {
+		return
+	}
+
+	q.lock.Lock()
+	q.items = append(q.items, items...)
+	q.lock.Unlock()
+}
+
+// Pop returns the head of items.
+func (q *Queue) Pop() interface{} {
+	if len(q.items) == 0 {
+		return nil
+	}
+
+	q.lock.Lock()
+	head := q.items[0]
+	q.items = q.items[1:]
+	q.lock.Unlock()
+	return head
+}
+
+// First returns the head of items without deleting.
+func (q *Queue) First() interface{} {
+	if len(q.items) == 0 {
+		return nil
+	}
+
+	q.lock.RLock()
+	head := q.items[0]
+	q.lock.RUnlock()
+	return head
+}
+
+// Copy get the copy of queue.
+func (q *Queue) Copy() []interface{} {
+	items := []interface{}{}
+	q.lock.RLock()
+	items = append(items, q.items...)
+	q.lock.RUnlock()
+	return items
+}
+
+// Len returns the number of items in this queue.
+func (q *Queue) Len() int64 {
+	q.lock.Lock()
+	defer q.lock.Unlock()
+
+	return int64(len(q.items))
+}
+
+// New is a constructor for a new concurrent safe queue.
+func New(hint int64) *Queue {
+	return &Queue{
+		items: make([]interface{}, 0, hint),
+	}
+}