github.com/Cleverse/go-ethereum@v0.0.0-20220927095127-45113064e7f2/p2p/util.go (about)

     1  // Copyright 2019 The go-ethereum Authors
     2  // This file is part of the go-ethereum library.
     3  //
     4  // The go-ethereum library is free software: you can redistribute it and/or modify
     5  // it under the terms of the GNU Lesser General Public License as published by
     6  // the Free Software Foundation, either version 3 of the License, or
     7  // (at your option) any later version.
     8  //
     9  // The go-ethereum library is distributed in the hope that it will be useful,
    10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    12  // GNU Lesser General Public License for more details.
    13  //
    14  // You should have received a copy of the GNU Lesser General Public License
    15  // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
    16  
    17  package p2p
    18  
    19  import (
    20  	"container/heap"
    21  
    22  	"github.com/ethereum/go-ethereum/common/mclock"
    23  )
    24  
    25  // expHeap tracks strings and their expiry time.
    26  type expHeap []expItem
    27  
    28  // expItem is an entry in addrHistory.
    29  type expItem struct {
    30  	item string
    31  	exp  mclock.AbsTime
    32  }
    33  
    34  // nextExpiry returns the next expiry time.
    35  func (h *expHeap) nextExpiry() mclock.AbsTime {
    36  	return (*h)[0].exp
    37  }
    38  
    39  // add adds an item and sets its expiry time.
    40  func (h *expHeap) add(item string, exp mclock.AbsTime) {
    41  	heap.Push(h, expItem{item, exp})
    42  }
    43  
    44  // contains checks whether an item is present.
    45  func (h expHeap) contains(item string) bool {
    46  	for _, v := range h {
    47  		if v.item == item {
    48  			return true
    49  		}
    50  	}
    51  	return false
    52  }
    53  
    54  // expire removes items with expiry time before 'now'.
    55  func (h *expHeap) expire(now mclock.AbsTime, onExp func(string)) {
    56  	for h.Len() > 0 && h.nextExpiry() < now {
    57  		item := heap.Pop(h)
    58  		if onExp != nil {
    59  			onExp(item.(expItem).item)
    60  		}
    61  	}
    62  }
    63  
    64  // heap.Interface boilerplate
    65  func (h expHeap) Len() int            { return len(h) }
    66  func (h expHeap) Less(i, j int) bool  { return h[i].exp < h[j].exp }
    67  func (h expHeap) Swap(i, j int)       { h[i], h[j] = h[j], h[i] }
    68  func (h *expHeap) Push(x interface{}) { *h = append(*h, x.(expItem)) }
    69  func (h *expHeap) Pop() interface{} {
    70  	old := *h
    71  	n := len(old)
    72  	x := old[n-1]
    73  	*h = old[0 : n-1]
    74  	return x
    75  }