block.go

package main

import (
	"bytes"
	"encoding/binary"
	"encoding/gob"
	"log"
	"time"
	"crypto/sha256"
	"fmt"
)

//1. 定义区块结构
type Block struct {
	//1. 版本号
	Version uint64
	//2. 前区块哈希
	PrevHash []byte
	//3. 梅克尔根
	MerkelRoot []byte
	//4. 时间戳
	TimeStamp uint64
	//5. 难度值
	Difficulty uint64
	//6. 随机数
	Nonce uint64

	//a. 当前区块哈希,正常比特币区块中没有当前区块的哈希！
	Hash []byte
	//b. 交易数据
	//Data []byte
	//使用切片存储一个区块中的所有交易信息（比特币大约200-2200不等）
	Transactions []*Transaction
}

//序列化
func (block *Block) Serialize() []byte {
	var buffer bytes.Buffer
	encoder := gob.NewEncoder(&buffer)
	err := encoder.Encode(&block)
	if err != nil {
		log.Panic("编码出错！", err)
	}
	return buffer.Bytes()
}

//反序列化
func Deserialize(data []byte) Block {

	decoder := gob.NewDecoder(bytes.NewReader(data))

	var block Block
	//使用解码器进行解码
	err := decoder.Decode(&block)
	if err != nil {
		log.Panic("解码出错!", err)
	}
	return block
}

func Uint64ToByte(num uint64) []byte {
	var buffer bytes.Buffer
	err := binary.Write(&buffer, binary.BigEndian, num)
	if err != nil {
		log.Panic(err)
	}

	return buffer.Bytes()
}

//2. 创建区块
func NewBlock(txs []*Transaction, prevBlockHash []byte) *Block {
	fmt.Println("正在挖矿...")
	block := Block{
		Version:    00,
		PrevHash:   prevBlockHash,
		MerkelRoot: []byte{},
		TimeStamp:  uint64(time.Now().Unix()),
		Difficulty: 0,
		Nonce:      0,
		Hash:       []byte{},
		//Data:       []byte(data),
		Transactions:txs,
	}

	block.SetMerkelRoot()

	pow := NewProofOfWork(&block)
	block.Hash, block.Nonce = pow.Run()
	return &block
}

//3. 为Block绑定方法生成哈希
/*func (block *Block) SetHash() {
	var blockInfo []byte
	//1. 拼接数据
	//blockInfo = append(blockInfo, Uint64ToByte(block.Version)...)
	//blockInfo = append(blockInfo, block.PrevHash...)
	//blockInfo = append(blockInfo, block.MerkelRoot...)
	//blockInfo = append(blockInfo, Uint64ToByte(block.TimeStamp)...)
	//blockInfo = append(blockInfo, Uint64ToByte(block.Difficulty)...)
	//blockInfo = append(blockInfo, Uint64ToByte(block.Nonce)...)
	////blockInfo = append(block.PrevHash, block.Data...)//错误
	//blockInfo = append(blockInfo, block.Data...)

	//简化一下
	tmp := [][]byte{
		Uint64ToByte(block.Version),
		block.PrevHash,
		block.MerkelRoot,
		Uint64ToByte(block.TimeStamp),
		Uint64ToByte(block.Difficulty),
		Uint64ToByte(block.Nonce),
		block.Data,
	}

	blockInfo=bytes.Join(tmp,[]byte{})

	//2. sha256
	hash := sha256.Sum256(blockInfo)
	block.Hash = hash[:]
}*/

//生成梅克尔根，只是对交易数据作简单处理，不做二叉树处理
func (block *Block)SetMerkelRoot()  {
	var info []byte
	for _, tx := range block.Transactions {
		//将交易的交易ID拼接起来，再整体做哈希处理
		info = append(info, tx.TXId...)
	}
	hash := sha256.Sum256(info)
	block.MerkelRoot=hash[:]
}