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blockchain.go
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blockchain.go
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package main
import (
"github.com/dgraph-io/badger/v3"
)
type Blockchain struct {
LastBlock *Block
db *badger.DB
}
func NewBlockchain(db *badger.DB, root *Block) (*Blockchain, error) {
bc := &Blockchain{db: db}
return bc, bc.AddBlock(root)
}
func LoadBlockchain(db *badger.DB) (*Blockchain, error) {
bc := &Blockchain{db: db}
lastB, err := bc.GetLastBlock()
bc.LastBlock = lastB
return bc, err
}
func (bc *Blockchain) GetLastBlock() (*Block, error) {
var b *Block
err := bc.db.View(func(txn *badger.Txn) error {
item, err := txn.Get([]byte("last_block"))
if err != nil {
return err
}
var hash []byte
err = item.Value(func(val []byte) error {
hash = append([]byte{}, val...)
return nil
})
if err != nil {
return err
}
b, err = bc.GetBlock(hash)
return err
})
return b, err
}
func (bc *Blockchain) GetBlock(key []byte) (*Block, error) {
var b *Block
err := bc.db.View(func(txn *badger.Txn) error {
item, err := txn.Get(key)
if err != nil {
return err
}
return item.Value(func(val []byte) error {
b, err = DeserializeBlock(append([]byte{}, val...))
return err
})
})
return b, err
}
func (bc *Blockchain) AddBlock(b *Block) error {
err := bc.db.Update(func(txn *badger.Txn) error {
s, err := b.Serialize()
if err != nil {
return err
}
err = txn.Set(b.Hash[:], s)
if err != nil {
return err
}
return txn.Set([]byte("last_block"), b.Hash[:])
})
if err != nil {
return err
}
bc.LastBlock = b
return nil
}
func (bc *Blockchain) Iterator() *BlockchainIterator {
return NewIterator(bc)
}