neo-go/pkg/database/leveldb.go
decentralisedkev 30e5aa8f48
Add Chain saving functionality to Database (#206)
* [database]

- Add Prefix method to interface
- Convert leveldb error to `database error`
- Be explicit with prefixedKey in `Table` as slices can be pointers

* [protocol]
- Add stringer method to protocol

* [Chaindb]

- Added saveBlock() which will allow us to save a block into the
database. The block is broken up into transactions and Headers. The
headers are saved as is. The transactions are saved as is, then the
utxos in the transactions are collected to make the utxo db.

- Verification for blocks and transactions will reside in the same
package. Note that the save methods are all unexported, while the Get
methods are exported. Making it so that any can call a get method, but
only code in this package may save to the database. The other code which
will reside in this package will be code verification logic.

* [chaindb]

- Added saveHeader function which saveHeaders  uses

- Update the latest header, each time we save a header instead of after a batch. This is so that we can call saveHeader without saveHeaders. This functionality can be rolled back if the performance of updating the header after a batch is significant

- small refactor in test code
2019-03-23 16:57:05 +00:00

114 lines
2.6 KiB
Go

package database
import (
"github.com/syndtr/goleveldb/leveldb"
"github.com/syndtr/goleveldb/leveldb/errors"
ldbutil "github.com/syndtr/goleveldb/leveldb/util"
)
//DbDir is the folder which all database files will be put under
// Structure /DbDir/net
const DbDir = "db/"
// LDB represents a leveldb object
type LDB struct {
db *leveldb.DB
Path string
}
// ErrNotFound means that the value was not found in the db
var ErrNotFound = errors.New("value not found for that key")
// Database contains all methods needed for an object to be a database
type Database interface {
// Has checks whether the key is in the database
Has(key []byte) (bool, error)
// Put adds the key value pair into the pair
Put(key []byte, value []byte) error
// Get returns the value for the given key
Get(key []byte) ([]byte, error)
// Delete deletes the given value for the key from the database
Delete(key []byte) error
//Prefix returns all values that start with key
Prefix(key []byte) ([][]byte, error)
// Close closes the underlying db object
Close() error
}
// New will return a new leveldb instance
func New(path string) (*LDB, error) {
dbPath := DbDir + path
db, err := leveldb.OpenFile(dbPath, nil)
if err != nil {
return nil, err
}
if _, corrupted := err.(*errors.ErrCorrupted); corrupted {
db, err = leveldb.RecoverFile(path, nil)
if err != nil {
return nil, err
}
}
return &LDB{
db,
dbPath,
}, nil
}
// Has implements the database interface
func (l *LDB) Has(key []byte) (bool, error) {
return l.db.Has(key, nil)
}
// Put implements the database interface
func (l *LDB) Put(key []byte, value []byte) error {
return l.db.Put(key, value, nil)
}
// Get implements the database interface
func (l *LDB) Get(key []byte) ([]byte, error) {
val, err := l.db.Get(key, nil)
if err == nil {
return val, nil
}
if err == leveldb.ErrNotFound {
return val, ErrNotFound
}
return val, err
}
// Delete implements the database interface
func (l *LDB) Delete(key []byte) error {
return l.db.Delete(key, nil)
}
// Close implements the database interface
func (l *LDB) Close() error {
return l.db.Close()
}
// Prefix implements the database interface
func (l *LDB) Prefix(key []byte) ([][]byte, error) {
var results [][]byte
iter := l.db.NewIterator(ldbutil.BytesPrefix(key), nil)
for iter.Next() {
value := iter.Value()
// Copy the data, as we cannot modify it
// Once the iter has been released
deref := make([]byte, len(value))
copy(deref, value)
// Append result
results = append(results, deref)
}
iter.Release()
err := iter.Error()
return results, err
}