106 lines
2.0 KiB
Go
106 lines
2.0 KiB
Go
package blockchain
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import (
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"fmt"
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"github.com/dgraph-io/badger"
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)
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const (
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dbPath = "./tmp/blocks"
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)
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type BlockChain struct {
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LastHash []byte
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Database *badger.DB
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}
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type BlockChainIterator struct {
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CurrentHash []byte
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Database *badger.DB
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}
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func InitBlockChain() *BlockChain {
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var lastHash []byte
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opts := badger.DefaultOptions(dbPath)
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opts.Logger = nil
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db, err := badger.Open(opts)
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Handle(err)
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err = db.Update(func(txn *badger.Txn) error {
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if _, err := txn.Get([]byte("lh")); err == badger.ErrKeyNotFound {
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fmt.Println("No existing blockchain found")
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genesis := Genesis()
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fmt.Println("Genesis proved")
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err = txn.Set(genesis.Hash, genesis.Serialize())
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Handle(err)
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err = txn.Set([]byte("lh"), genesis.Hash)
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lastHash = genesis.Hash
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return err
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} else {
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item, err := txn.Get([]byte("lh"))
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Handle(err)
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lastHash, err = item.ValueCopy(nil)
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return err
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}
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})
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Handle(err)
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blockchain := BlockChain{lastHash, db}
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return &blockchain
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}
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func (chain *BlockChain) AddBlock(data string) {
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var lastHash []byte
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err := chain.Database.View(func(txn *badger.Txn) error {
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item, err := txn.Get([]byte("lh"))
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Handle(err)
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lastHash, err = item.ValueCopy(nil)
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return err
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})
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Handle(err)
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newBlock := CreateBlock(data, lastHash)
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err = chain.Database.Update(func(txn *badger.Txn) error {
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err := txn.Set(newBlock.Hash, newBlock.Serialize())
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Handle(err)
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err = txn.Set([]byte("lh"), newBlock.Hash)
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chain.LastHash = newBlock.Hash
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return err
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})
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Handle(err)
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}
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func (chain *BlockChain) Iterator() *BlockChainIterator {
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iter := &BlockChainIterator{chain.LastHash, chain.Database}
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return iter
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}
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func (iter *BlockChainIterator) Next() *Block {
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var block *Block
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err := iter.Database.View(func(txn *badger.Txn) error {
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item, err := txn.Get(iter.CurrentHash)
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Handle(err)
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encodedBlock, err := item.ValueCopy(nil)
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block = Deserialize(encodedBlock)
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return err
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})
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Handle(err)
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iter.CurrentHash = block.PrevHash
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return block
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}
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