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blockchain.go
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blockchain.go
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package main
import "github.com/boltdb/bolt"
const dbFile = "blockchain.db"
const blockBucket = "block_bucket"
type Blockchain struct {
tip []byte
db *bolt.DB
}
type BlockchainIterator struct {
currentHash []byte
db *bolt.DB
}
func (bc *Blockchain) AddBlocks(data string) {
var lastHash []byte
err := bc.db.View(func(tx *bolt.Tx) error {
b := tx.Bucket([]byte(blockBucket))
lastHash = b.Get([]byte("l"))
return nil
})
logError(err)
newBlock := newBlock(data, lastHash)
err = bc.db.Update(func(tx *bolt.Tx) error {
b := tx.Bucket([]byte(blockBucket))
newBlockHash := newBlock.Hash
err := b.Put(newBlockHash, newBlock.Serialize())
logError(err)
err = b.Put([]byte("l"), newBlockHash)
logError(err)
bc.tip = newBlockHash
return nil
})
logError(err)
}
func NewBlockChain() *Blockchain {
var tip []byte
db, err := bolt.Open(dbFile, 0600, nil)
logError(err)
err = db.Update(func(tx *bolt.Tx) error {
b := tx.Bucket([]byte(blockBucket))
if b == nil {
genesis := genesisBlock()
b, err := tx.CreateBucket([]byte(blockBucket))
logError(err)
err = b.Put(genesis.Hash, genesis.Serialize())
logError(err)
err = b.Put([]byte("l"), genesis.Hash)
logError(err)
tip = genesis.Hash
} else {
tip = b.Get([]byte("l"))
}
// return nil to commit transaction
return nil
})
logError(err)
bc := Blockchain{tip, db}
return &bc
}
func (bc *Blockchain) Iterator() *BlockchainIterator {
bci := BlockchainIterator{bc.tip, bc.db}
return &bci
}
func (i *BlockchainIterator) Next() *Block {
var block *Block
err := i.db.View(func(tx *bolt.Tx) error {
b := tx.Bucket([]byte(blockBucket))
encodedBlock := b.Get(i.currentHash)
block = Deserialize(encodedBlock)
return nil
})
logError(err)
i.currentHash = block.PrevBlockHash
return block
}