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goleveldb.go
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goleveldb.go
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package db
import (
"fmt"
"path/filepath"
"github.com/syndtr/goleveldb/leveldb"
"github.com/syndtr/goleveldb/leveldb/errors"
"github.com/syndtr/goleveldb/leveldb/opt"
"github.com/syndtr/goleveldb/leveldb/util"
)
func init() {
dbCreator := func(name string, dir string) (DB, error) {
return NewGoLevelDB(name, dir)
}
registerDBCreator(GoLevelDBBackend, dbCreator, false)
}
type GoLevelDB struct {
name string
db *leveldb.DB
}
var _ DB = (*GoLevelDB)(nil)
func NewGoLevelDB(name string, dir string) (*GoLevelDB, error) {
return NewGoLevelDBWithOpts(name, dir, nil)
}
func NewGoLevelDBWithOpts(name string, dir string, o *opt.Options) (*GoLevelDB, error) {
dbPath := filepath.Join(dir, name+".db")
db, err := leveldb.OpenFile(dbPath, o)
if err != nil {
return nil, err
}
database := &GoLevelDB{
name: name,
db: db,
}
return database, nil
}
func (db *GoLevelDB) Name() string {
return db.name
}
// Get implements DB.
func (db *GoLevelDB) Get(key []byte) ([]byte, error) {
if len(key) == 0 {
return nil, errKeyEmpty
}
res, err := db.db.Get(key, nil)
if err != nil {
if err == errors.ErrNotFound {
return nil, nil
}
return nil, err
}
return res, nil
}
// Has implements DB.
func (db *GoLevelDB) Has(key []byte) (bool, error) {
bytes, err := db.Get(key)
if err != nil {
return false, err
}
return bytes != nil, nil
}
// Set implements DB.
func (db *GoLevelDB) Set(key []byte, value []byte) error {
if len(key) == 0 {
return errKeyEmpty
}
if value == nil {
return errValueNil
}
return db.db.Put(key, value, nil)
}
// SetSync implements DB.
func (db *GoLevelDB) SetSync(key []byte, value []byte) error {
if len(key) == 0 {
return errKeyEmpty
}
if value == nil {
return errValueNil
}
return db.db.Put(key, value, &opt.WriteOptions{Sync: true})
}
// Delete implements DB.
func (db *GoLevelDB) Delete(key []byte) error {
if len(key) == 0 {
return errKeyEmpty
}
return db.db.Delete(key, nil)
}
// DeleteSync implements DB.
func (db *GoLevelDB) DeleteSync(key []byte) error {
if len(key) == 0 {
return errKeyEmpty
}
return db.db.Delete(key, &opt.WriteOptions{Sync: true})
}
func (db *GoLevelDB) DB() *leveldb.DB {
return db.db
}
// Close implements DB.
func (db *GoLevelDB) Close() error {
return db.db.Close()
}
// Print implements DB.
func (db *GoLevelDB) Print() error {
str, err := db.db.GetProperty("leveldb.stats")
if err != nil {
return err
}
fmt.Printf("%v\n", str)
itr := db.db.NewIterator(nil, nil)
for itr.Next() {
key := itr.Key()
value := itr.Value()
fmt.Printf("[%X]:\t[%X]\n", key, value)
}
return nil
}
// Stats implements DB.
func (db *GoLevelDB) Stats() map[string]string {
keys := []string{
"leveldb.num-files-at-level{n}",
"leveldb.stats",
"leveldb.sstables",
"leveldb.blockpool",
"leveldb.cachedblock",
"leveldb.openedtables",
"leveldb.alivesnaps",
"leveldb.aliveiters",
}
stats := make(map[string]string)
for _, key := range keys {
str, err := db.db.GetProperty(key)
if err == nil {
stats[key] = str
}
}
return stats
}
// NewBatch implements DB.
func (db *GoLevelDB) NewBatch() Batch {
return newGoLevelDBBatch(db)
}
// Iterator implements DB.
func (db *GoLevelDB) Iterator(start, end []byte) (Iterator, error) {
if (start != nil && len(start) == 0) || (end != nil && len(end) == 0) {
return nil, errKeyEmpty
}
itr := db.db.NewIterator(&util.Range{Start: start, Limit: end}, nil)
return newGoLevelDBIterator(itr, false), nil
}
func (db *GoLevelDB) PrefixIterator(prefix []byte) (Iterator, error) {
if len(prefix) == 0 {
return nil, errKeyEmpty
}
itr := db.db.NewIterator(util.BytesPrefix(prefix), nil)
return newGoLevelDBIterator(itr, false), nil
}
// ReverseIterator implements DB.
func (db *GoLevelDB) ReverseIterator(start, end []byte) (Iterator, error) {
if (start != nil && len(start) == 0) || (end != nil && len(end) == 0) {
return nil, errKeyEmpty
}
itr := db.db.NewIterator(&util.Range{Start: start, Limit: end}, nil)
return newGoLevelDBIterator(itr, true), nil
}
func (db *GoLevelDB) ReversePrefixIterator(prefix []byte) (Iterator, error) {
if len(prefix) == 0 {
return nil, errKeyEmpty
}
itr := db.db.NewIterator(util.BytesPrefix(prefix), nil)
return newGoLevelDBIterator(itr, true), nil
}