fix

pkg/pqueue/pqueue.go

@@ -0,0 +1,89 @@
+// Package pqueue jiacrontab中使用的优先队列
+// 参考nsq的实现
+// 做了注释和少量调整
+package pqueue
+
+import (
+	"container/heap"
+)
+
+type Item struct {
+	Value    interface{}
+	Priority int64
+	Index    int
+}
+
+// PriorityQueue 最小堆实现的优先队列
+type PriorityQueue []*Item
+
+// New 创建
+func New(capacity int) PriorityQueue {
+	return make(PriorityQueue, 0, capacity)
+}
+
+// Len 队列长队
+func (pq PriorityQueue) Len() int {
+	return len(pq)
+}
+
+// Less 比较相邻两个原素优先级
+func (pq PriorityQueue) Less(i, j int) bool {
+	return pq[i].Priority < pq[j].Priority
+}
+
+// Swap 交换相邻原素
+func (pq PriorityQueue) Swap(i, j int) {
+	pq[i], pq[j] = pq[j], pq[i]
+	pq[i].Index = i
+	pq[j].Index = j
+}
+
+// Push 添加新的item
+func (pq *PriorityQueue) Push(x interface{}) {
+	n := len(*pq)
+	c := cap(*pq)
+	if n+1 > c {
+		npq := make(PriorityQueue, n, c*2)
+		copy(npq, *pq)
+		*pq = npq
+	}
+	*pq = (*pq)[0 : n+1]
+	item := x.(*Item)
+	item.Index = n
+	(*pq)[n] = item
+}
+
+func (pq *PriorityQueue) update(item *Item, value string, priority int64) {
+	item.Value = value
+	item.Priority = priority
+	heap.Fix(pq, item.Index)
+}
+
+// Pop 弹出队列末端原素
+func (pq *PriorityQueue) Pop() interface{} {
+	n := len(*pq)
+	c := cap(*pq)
+	if n < (c/2) && c > 25 {
+		npq := make(PriorityQueue, n, c/2)
+		copy(npq, *pq)
+		*pq = npq
+	}
+	item := (*pq)[n-1]
+	item.Index = -1
+	*pq = (*pq)[0 : n-1]
+	return item
+}
+
+// PeekAndShift 根据比较max并弹出原素
+func (pq *PriorityQueue) PeekAndShift(max int64) (*Item, int64) {
+	if pq.Len() == 0 {
+		return nil, 0
+	}
+
+	item := (*pq)[0]
+	if item.Priority > max {
+		return nil, item.Priority - max
+	}
+	heap.Remove(pq, 0)
+	return item, 0
+}