72 lines
1.3 KiB
Go
72 lines
1.3 KiB
Go
package ttlcache
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import (
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"container/heap"
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)
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func newPriorityQueue() *priorityQueue {
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queue := &priorityQueue{}
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heap.Init(queue)
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return queue
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}
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type priorityQueue struct {
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items []*item
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}
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func (pq *priorityQueue) update(item *item) {
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heap.Fix(pq, item.queueIndex)
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}
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func (pq *priorityQueue) push(item *item) {
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heap.Push(pq, item)
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}
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func (pq *priorityQueue) pop() *item {
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if pq.Len() == 0 {
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return nil
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}
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return heap.Pop(pq).(*item)
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}
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func (pq *priorityQueue) remove(item *item) {
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heap.Remove(pq, item.queueIndex)
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}
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func (pq priorityQueue) Len() int {
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length := len(pq.items)
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return length
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}
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// Less will consider items with time.Time default value (epoch start) as more than set items.
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func (pq priorityQueue) Less(i, j int) bool {
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if pq.items[i].expireAt.IsZero() {
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return false
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}
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if pq.items[j].expireAt.IsZero() {
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return true
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}
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return pq.items[i].expireAt.Before(pq.items[j].expireAt)
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}
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func (pq priorityQueue) Swap(i, j int) {
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pq.items[i], pq.items[j] = pq.items[j], pq.items[i]
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pq.items[i].queueIndex = i
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pq.items[j].queueIndex = j
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}
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func (pq *priorityQueue) Push(x interface{}) {
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item := x.(*item)
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item.queueIndex = len(pq.items)
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pq.items = append(pq.items, item)
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}
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func (pq *priorityQueue) Pop() interface{} {
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old := pq.items
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n := len(old)
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item := old[n-1]
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item.queueIndex = -1
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pq.items = old[0 : n-1]
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return item
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}
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