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storage.go
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storage.go
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package goleveldb
import (
"bytes"
"errors"
"io/ioutil"
"os"
"github.com/syndtr/goleveldb/leveldb"
"github.com/syndtr/goleveldb/leveldb/util"
"github.com/aptly-dev/aptly/database"
)
type storage struct {
path string
db *leveldb.DB
}
// CreateTemporary creates new DB of the same type in temp dir
func (s *storage) CreateTemporary() (database.Storage, error) {
tempdir, err := ioutil.TempDir("", "aptly")
if err != nil {
return nil, err
}
db, err := internalOpen(tempdir, true)
if err != nil {
return nil, err
}
return &storage{db: db, path: tempdir}, nil
}
// Get key value from database
func (s *storage) Get(key []byte) ([]byte, error) {
value, err := s.db.Get(key, nil)
if err != nil {
if err == leveldb.ErrNotFound {
return nil, database.ErrNotFound
}
return nil, err
}
return value, nil
}
// Put saves key to database, if key has the same value in DB already, it is not saved
func (s *storage) Put(key []byte, value []byte) error {
old, err := s.db.Get(key, nil)
if err != nil {
if err != leveldb.ErrNotFound {
return err
}
} else {
if bytes.Equal(old, value) {
return nil
}
}
return s.db.Put(key, value, nil)
}
// Delete removes key from DB
func (s *storage) Delete(key []byte) error {
return s.db.Delete(key, nil)
}
// KeysByPrefix returns all keys that start with prefix
func (s *storage) KeysByPrefix(prefix []byte) [][]byte {
result := make([][]byte, 0, 20)
iterator := s.db.NewIterator(nil, nil)
defer iterator.Release()
for ok := iterator.Seek(prefix); ok && bytes.HasPrefix(iterator.Key(), prefix); ok = iterator.Next() {
key := iterator.Key()
keyc := make([]byte, len(key))
copy(keyc, key)
result = append(result, keyc)
}
return result
}
// FetchByPrefix returns all values with keys that start with prefix
func (s *storage) FetchByPrefix(prefix []byte) [][]byte {
result := make([][]byte, 0, 20)
iterator := s.db.NewIterator(nil, nil)
defer iterator.Release()
for ok := iterator.Seek(prefix); ok && bytes.HasPrefix(iterator.Key(), prefix); ok = iterator.Next() {
val := iterator.Value()
valc := make([]byte, len(val))
copy(valc, val)
result = append(result, valc)
}
return result
}
// HasPrefix checks whether it can find any key with given prefix and returns true if one exists
func (s *storage) HasPrefix(prefix []byte) bool {
iterator := s.db.NewIterator(nil, nil)
defer iterator.Release()
return iterator.Seek(prefix) && bytes.HasPrefix(iterator.Key(), prefix)
}
// ProcessByPrefix iterates through all entries where key starts with prefix and calls
// StorageProcessor on key value pair
func (s *storage) ProcessByPrefix(prefix []byte, proc database.StorageProcessor) error {
iterator := s.db.NewIterator(nil, nil)
defer iterator.Release()
for ok := iterator.Seek(prefix); ok && bytes.HasPrefix(iterator.Key(), prefix); ok = iterator.Next() {
err := proc(iterator.Key(), iterator.Value())
if err != nil {
return err
}
}
return nil
}
// Close finishes DB work
func (s *storage) Close() error {
if s.db == nil {
return nil
}
err := s.db.Close()
s.db = nil
return err
}
// Reopen tries to open (re-open) the database
func (s *storage) Open() error {
if s.db != nil {
return nil
}
var err error
s.db, err = internalOpen(s.path, false)
return err
}
// CreateBatch creates a Batch object
func (s *storage) CreateBatch() database.Batch {
return &batch{
db: s.db,
b: &leveldb.Batch{},
}
}
// OpenTransaction creates new transaction.
func (s *storage) OpenTransaction() (database.Transaction, error) {
t, err := s.db.OpenTransaction()
if err != nil {
return nil, err
}
return &transaction{t: t}, nil
}
// CompactDB compacts database by merging layers
func (s *storage) CompactDB() error {
return s.db.CompactRange(util.Range{})
}
// Drop removes all the DB files (DANGEROUS!)
func (s *storage) Drop() error {
if s.db != nil {
return errors.New("DB is still open")
}
return os.RemoveAll(s.path)
}
// Check interface
var (
_ database.Storage = &storage{}
)