97 lines
1.9 KiB
Go
97 lines
1.9 KiB
Go
package utils
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import (
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"encoding/binary"
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"encoding/hex"
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"fmt"
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"github.com/ledgerwatch/lmdb-go/lmdb"
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)
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const (
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DefaultIndexPrefix = "indexes/"
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)
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var (
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ErrIndexKeyNotFound = fmt.Errorf("key is not found in the index")
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)
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type Index struct {
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name string
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dbEnv *lmdb.Env
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db lmdb.DBI
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}
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func NewIndex(name string, dbEnv *lmdb.Env, db lmdb.DBI) *Index {
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return &Index{
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name: name,
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db: db,
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dbEnv: dbEnv,
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}
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}
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func (i *Index) PutUint64(key []byte, value uint64) error {
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return i.dbEnv.Update(func(txn *lmdb.Txn) error {
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var data []byte
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binary.LittleEndian.PutUint64(data, value)
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return txn.Put(i.db, i.constructIndexKey(key), data, 0)
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})
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}
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func (i *Index) GetUint64(key []byte) (uint64, error) {
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var num uint64
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err := i.dbEnv.View(func(txn *lmdb.Txn) error {
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data, err := txn.Get(i.db, i.constructIndexKey(key))
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if err != nil {
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if lmdb.IsNotFound(err) {
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return ErrIndexKeyNotFound
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}
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return err
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}
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num = binary.LittleEndian.Uint64(data)
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return nil
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})
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if err != nil {
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return 0, err
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}
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return num, nil
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}
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func (i *Index) PutBytes(key []byte, value []byte) error {
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return i.dbEnv.Update(func(txn *lmdb.Txn) error {
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return txn.Put(i.db, i.constructIndexKey(key), value, 0)
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})
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}
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func (i *Index) GetBytes(key []byte) ([]byte, error) {
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var data []byte
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err := i.dbEnv.View(func(txn *lmdb.Txn) error {
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valueData, err := txn.Get(i.db, i.constructIndexKey(key))
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if err != nil {
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if lmdb.IsNotFound(err) {
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return ErrIndexKeyNotFound
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}
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return err
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}
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data = valueData
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return nil
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})
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if err != nil {
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return nil, err
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}
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return data, nil
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}
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func (i *Index) Delete(key []byte) error {
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return i.dbEnv.Update(func(txn *lmdb.Txn) error {
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return txn.Del(i.db, i.constructIndexKey(key), nil)
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})
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}
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func (i *Index) constructIndexKey(key []byte) []byte {
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k := hex.EncodeToString(key)
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return []byte(fmt.Sprintf("%s/%s/%s", DefaultIndexPrefix, i.name, k))
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}
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