06632da2bb
This changes the Pop method to assign the zero value before reducing slice size. Doing so ensures the backing array does not reference removed item values.
77 lines
2.1 KiB
Go
77 lines
2.1 KiB
Go
// Copyright 2019 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package p2p
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import (
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"container/heap"
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"github.com/ethereum/go-ethereum/common/mclock"
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)
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// expHeap tracks strings and their expiry time.
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type expHeap []expItem
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// expItem is an entry in addrHistory.
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type expItem struct {
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item string
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exp mclock.AbsTime
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}
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// nextExpiry returns the next expiry time.
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func (h *expHeap) nextExpiry() mclock.AbsTime {
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return (*h)[0].exp
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}
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// add adds an item and sets its expiry time.
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func (h *expHeap) add(item string, exp mclock.AbsTime) {
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heap.Push(h, expItem{item, exp})
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}
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// contains checks whether an item is present.
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func (h expHeap) contains(item string) bool {
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for _, v := range h {
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if v.item == item {
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return true
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}
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}
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return false
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}
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// expire removes items with expiry time before 'now'.
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func (h *expHeap) expire(now mclock.AbsTime, onExp func(string)) {
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for h.Len() > 0 && h.nextExpiry() < now {
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item := heap.Pop(h)
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if onExp != nil {
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onExp(item.(expItem).item)
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}
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}
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}
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// heap.Interface boilerplate
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func (h expHeap) Len() int { return len(h) }
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func (h expHeap) Less(i, j int) bool { return h[i].exp < h[j].exp }
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func (h expHeap) Swap(i, j int) { h[i], h[j] = h[j], h[i] }
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func (h *expHeap) Push(x interface{}) { *h = append(*h, x.(expItem)) }
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func (h *expHeap) Pop() interface{} {
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old := *h
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n := len(old)
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x := old[n-1]
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old[n-1] = expItem{}
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*h = old[0 : n-1]
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return x
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}
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