github.com/jiajun1992/watercarver@v0.0.0-20191031150618-dfc2b17c0c4a/go-ethereum/cmd/devp2p/nodeset.go (about)

     1  // Copyright 2019 The go-ethereum Authors
     2  // This file is part of go-ethereum.
     3  //
     4  // go-ethereum is free software: you can redistribute it and/or modify
     5  // it under the terms of the GNU 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  // go-ethereum 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 General Public License for more details.
    13  //
    14  // You should have received a copy of the GNU General Public License
    15  // along with go-ethereum. If not, see <http://www.gnu.org/licenses/>.
    16  
    17  package main
    18  
    19  import (
    20  	"bytes"
    21  	"encoding/json"
    22  	"fmt"
    23  	"io/ioutil"
    24  	"sort"
    25  
    26  	"github.com/ethereum/go-ethereum/common"
    27  	"github.com/ethereum/go-ethereum/p2p/enode"
    28  )
    29  
    30  const jsonIndent = "    "
    31  
    32  // nodeSet is the nodes.json file format. It holds a set of node records
    33  // as a JSON object.
    34  type nodeSet map[enode.ID]nodeJSON
    35  
    36  type nodeJSON struct {
    37  	Seq uint64      `json:"seq"`
    38  	N   *enode.Node `json:"record"`
    39  }
    40  
    41  func loadNodesJSON(file string) nodeSet {
    42  	var nodes nodeSet
    43  	if err := common.LoadJSON(file, &nodes); err != nil {
    44  		exit(err)
    45  	}
    46  	return nodes
    47  }
    48  
    49  func writeNodesJSON(file string, nodes nodeSet) {
    50  	nodesJSON, err := json.MarshalIndent(nodes, "", jsonIndent)
    51  	if err != nil {
    52  		exit(err)
    53  	}
    54  	if err := ioutil.WriteFile(file, nodesJSON, 0644); err != nil {
    55  		exit(err)
    56  	}
    57  }
    58  
    59  func (ns nodeSet) nodes() []*enode.Node {
    60  	result := make([]*enode.Node, 0, len(ns))
    61  	for _, n := range ns {
    62  		result = append(result, n.N)
    63  	}
    64  	// Sort by ID.
    65  	sort.Slice(result, func(i, j int) bool {
    66  		return bytes.Compare(result[i].ID().Bytes(), result[j].ID().Bytes()) < 0
    67  	})
    68  	return result
    69  }
    70  
    71  func (ns nodeSet) add(nodes ...*enode.Node) {
    72  	for _, n := range nodes {
    73  		ns[n.ID()] = nodeJSON{Seq: n.Seq(), N: n}
    74  	}
    75  }
    76  
    77  func (ns nodeSet) verify() error {
    78  	for id, n := range ns {
    79  		if n.N.ID() != id {
    80  			return fmt.Errorf("invalid node %v: ID does not match ID %v in record", id, n.N.ID())
    81  		}
    82  		if n.N.Seq() != n.Seq {
    83  			return fmt.Errorf("invalid node %v: 'seq' does not match seq %d from record", id, n.N.Seq())
    84  		}
    85  	}
    86  	return nil
    87  }