blockchain_newblockchain.go

package main

import (
	"fmt"
	"os"
	"github.com/boltdb/bolt"
	"log"
)

// CreateBlockchain creates a new blockchain DB
func CreateBlockchain(address, nodeID string) *Blockchain {

	dbFile := fmt.Sprintf(dbFile, nodeID)//nodeID不同，文件名字就会不同
	if dbExists(dbFile) {
		fmt.Println("Blockchain already exists.")
		os.Exit(1)
	}



	var tip []byte

	transaction:=NewCoinbaseTX(address,genesisCoinbaseData)
	genesis := NewGenesisBlock([]*Transaction{transaction})

	db, err := bolt.Open(dbFile, 0600, nil)
	if err != nil {
		log.Panic(err)
	}

	err = db.Update(func(tx *bolt.Tx) error {
		b, err := tx.CreateBucket([]byte(blocksBucket))
		if err != nil {
			log.Panic(err)
		}

		err = b.Put(genesis.Hash, genesis.Serialize())
		if err != nil {
			log.Panic(err)
		}

		err = b.Put([]byte("l"), genesis.Hash)
		if err != nil {
			log.Panic(err)
		}
		tip = genesis.Hash

		return nil
	})
	if err != nil {
		log.Panic(err)
	}

	bc := Blockchain{tip, db}

	return &bc
}

// NewBlockchain creates a new Blockchain with genesis Block
func NewBlockchain(nodeID string) *Blockchain {
	dbFile := fmt.Sprintf(dbFile, nodeID)//nodeID不同，文件名字就会不同
	if dbExists(dbFile) == false {
		fmt.Println("No existing blockchain found. Create one first.")
		os.Exit(1)
	}

	var tip []byte
	db, err := bolt.Open(dbFile, 0600, nil)
	if err != nil {
		log.Panic(err)
	}

	err = db.Update(func(tx *bolt.Tx) error {
		b := tx.Bucket([]byte(blocksBucket))
		tip = b.Get([]byte("l"))

		return nil
	})
	if err != nil {
		log.Panic(err)
	}

	bc := Blockchain{tip, db}

	return &bc
}