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// Copyright 2019 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package p2p
import (
"container/heap"
"github.com/ethereum/go-ethereum/common/mclock"
)
// expHeap tracks strings and their expiry time.
type expHeap []expItem
// expItem is an entry in addrHistory.
type expItem struct {
item string
exp mclock.AbsTime
}
// nextExpiry returns the next expiry time.
func (h *expHeap) nextExpiry() mclock.AbsTime {
return (*h)[0].exp
}
// add adds an item and sets its expiry time.
func (h *expHeap) add(item string, exp mclock.AbsTime) {
heap.Push(h, expItem{item, exp})
}
// contains checks whether an item is present.
func (h expHeap) contains(item string) bool {
for _, v := range h {
if v.item == item {
return true
}
}
return false
}
// expire removes items with expiry time before 'now'.
func (h *expHeap) expire(now mclock.AbsTime, onExp func(string)) {
for h.Len() > 0 && h.nextExpiry() < now {
item := heap.Pop(h)
if onExp != nil {
onExp(item.(expItem).item)
}
}
}
// heap.Interface boilerplate
func (h expHeap) Len() int { return len(h) }
func (h expHeap) Less(i, j int) bool { return h[i].exp < h[j].exp }
func (h expHeap) Swap(i, j int) { h[i], h[j] = h[j], h[i] }
func (h *expHeap) Push(x interface{}) { *h = append(*h, x.(expItem)) }
func (h *expHeap) Pop() interface{} {
old := *h
n := len(old)
x := old[n-1]
*h = old[0 : n-1]
return x
}