blockchain.go

package block_chain

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

const dbfile = "blockChainDb.db"
const blockBuckit = "blockBuckit"
const LASTHASH = "LASTHASH"

type BlockChain struct {
	//Blocks [] *Block

	db       *bolt.DB
	lastHash []byte
}

func NewBlockChain() *BlockChain {

	//return &BlockChain{ []*Block{NewGenesisBlock()},
	//}
	db, err := bolt.Open(dbfile, 0600, nil)
	CheckErr("newblockchain", err)

	lastHash:=[]byte{}
	db.Update(func(tx *bolt.Tx) error {
		bucket := tx.Bucket([]byte(blockBuckit))
		if bucket != nil {
			//读取hash即可
			lastHash = bucket.Get([]byte(LASTHASH))
		} else {
			//创建bucket
			//与数据
			genesis := NewGenesisBlock()
			bucket, err := tx.CreateBucket([]byte(blockBuckit))
			CheckErr("newblockchain", err)
			err = bucket.Put(genesis.Hash, genesis.Serialize()) //todo
			CheckErr("newblockchain", err)
			err = bucket.Put([]byte(LASTHASH), genesis.Hash)
			CheckErr("newblockchain", err)

		}
		return nil

	})

	return &BlockChain{db, lastHash}

}

func (bc *BlockChain) AddBlock(data string) {
	var prevBlockHash []byte
	err := bc.db.View(func(tx *bolt.Tx) error {
		bucket := tx.Bucket([]byte(blockBuckit))
		lastHash := bucket.Get([]byte(LASTHASH))

		prevBlockHash = lastHash

		return nil

	})

	CheckErr("", err)

	block := NewBlock(data, prevBlockHash)

	err = bc.db.Update(func(tx *bolt.Tx) error {

		bucket := tx.Bucket([]byte(blockBuckit))
		err := bucket.Put(block.Hash, block.Serialize())
		CheckErr("", err)

		err = bucket.Put([]byte(LASTHASH), block.Hash)
		CheckErr("AddBlock3", err)

		bc.lastHash = block.Hash
		fmt.Printf("after create block bc last hash is %x\n",bc.lastHash)

		return nil

	})
	CheckErr("", err)

}

type BlockChainIterator struct {
	db          *bolt.DB
	currentHash []byte
}

func (bc *BlockChain) Iterator() *BlockChainIterator {

	return &BlockChainIterator{bc.db, bc.lastHash}
}

func (it *BlockChainIterator) Next() *Block {
	var block *Block
	//fmt.Printf("iter current hash:%x\n",it.currentHash)
	err := it.db.View(func(tx *bolt.Tx) error {

		bucket := tx.Bucket([]byte(blockBuckit))

		if bucket == nil {
			fmt.Println("get bucket failed")
			os.Exit(1)

		}
		blockTmp := bucket.Get(it.currentHash)
		block = Deserialize(blockTmp)
		it.currentHash = block.PrevBlockHash
		return nil
	})
	CheckErr("Next", err)
	return block
}