neoneo-go/pkg/database/leveldb.go

115 lines
2.6 KiB
Go
Raw Normal View History

2019-02-25 22:44:14 +00:00
package database
import (
"github.com/syndtr/goleveldb/leveldb"
"github.com/syndtr/goleveldb/leveldb/errors"
ldbutil "github.com/syndtr/goleveldb/leveldb/util"
2019-02-25 22:44:14 +00:00
)
//DbDir is the folder which all database files will be put under
// Structure /DbDir/net
const DbDir = "db/"
// LDB represents a leveldb object
2019-02-25 22:44:14 +00:00
type LDB struct {
db *leveldb.DB
Path string
2019-02-25 22:44:14 +00:00
}
// 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
2019-02-25 22:44:14 +00:00
type Database interface {
// Has checks whether the key is in the database
2019-02-25 22:44:14 +00:00
Has(key []byte) (bool, error)
// Put adds the key value pair into the pair
2019-02-25 22:44:14 +00:00
Put(key []byte, value []byte) error
// Get returns the value for the given key
2019-02-25 22:44:14 +00:00
Get(key []byte) ([]byte, error)
// Delete deletes the given value for the key from the database
2019-02-25 22:44:14 +00:00
Delete(key []byte) error
//Prefix returns all values that start with key
Prefix(key []byte) ([][]byte, error)
// Close closes the underlying db object
2019-02-25 22:44:14 +00:00
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
}
2019-02-25 22:44:14 +00:00
if _, corrupted := err.(*errors.ErrCorrupted); corrupted {
db, err = leveldb.RecoverFile(path, nil)
if err != nil {
return nil, err
}
2019-02-25 22:44:14 +00:00
}
return &LDB{
db,
dbPath,
}, nil
2019-02-25 22:44:14 +00:00
}
// Has implements the database interface
2019-02-25 22:44:14 +00:00
func (l *LDB) Has(key []byte) (bool, error) {
return l.db.Has(key, nil)
}
// Put implements the database interface
2019-02-25 22:44:14 +00:00
func (l *LDB) Put(key []byte, value []byte) error {
return l.db.Put(key, value, nil)
}
// Get implements the database interface
2019-02-25 22:44:14 +00:00
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
2019-02-25 22:44:14 +00:00
}
// Delete implements the database interface
2019-02-25 22:44:14 +00:00
func (l *LDB) Delete(key []byte) error {
return l.db.Delete(key, nil)
}
// Close implements the database interface
2019-02-25 22:44:14 +00:00
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
}