-
Notifications
You must be signed in to change notification settings - Fork 0
/
blockchain.go
98 lines (77 loc) · 1.94 KB
/
blockchain.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
package blockchain
import (
"fmt"
"github.com/dgraph-io/badger"
)
const (
dbPath = "./tmp/blocks"
)
type BlockChain struct {
LastHash []byte
Database *badger.DB
}
type BlockChainIterator struct {
CurrentHash []byte
Database *badger.DB
}
func InitBlockChain() *BlockChain {
var lastHash []byte
db, err := badger.Open(badger.DefaultOptions(dbPath))
Handle(err)
err = db.Update(func(txn *badger.Txn) error {
if _, err := txn.Get([]byte("lh")); err == badger.ErrKeyNotFound {
fmt.Println("No existing blockchain found, create one first.")
genesis := Genesis()
fmt.Println("Genesis created")
err := txn.Set(genesis.Hash, genesis.Serialize())
Handle(err)
err = txn.Set([]byte("lh"), genesis.Hash)
lastHash = genesis.Hash
return err
} else {
item, err := txn.Get([]byte("lh"))
Handle(err)
lastHash, err = item.ValueCopy(nil)
return err
}
})
Handle(err)
BlockChain := BlockChain{lastHash, db}
return &BlockChain
}
func (chain *BlockChain) AddBlock(data string) {
var lastHash []byte
err := chain.Database.View(func(txn *badger.Txn) error {
item, err := txn.Get([]byte("lh"))
Handle(err)
lastHash, err = item.ValueCopy(nil)
return err
})
Handle(err)
newBlock := CreateBlock(data, lastHash)
err = chain.Database.Update(func(txn *badger.Txn) error {
err := txn.Set(newBlock.Hash, newBlock.Serialize())
Handle(err)
err = txn.Set([]byte("lh"), newBlock.Hash)
chain.LastHash = newBlock.Hash
return err
})
Handle(err)
}
func (chain *BlockChain) Iterator() *BlockChainIterator {
iter := &BlockChainIterator{chain.LastHash, chain.Database}
return iter
}
func (iter *BlockChainIterator) Next() *Block {
var block *Block
err := iter.Database.View(func(txn *badger.Txn) error {
item, err := txn.Get(iter.CurrentHash)
Handle(err)
encodedBlock, err := item.ValueCopy(nil)
block = Deserialize(encodedBlock)
return err
})
Handle(err)
iter.CurrentHash = block.PreviousHash
return block
}