115 lines
3.1 KiB
Go
115 lines
3.1 KiB
Go
// Copyright 2018 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package state
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import (
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"encoding"
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"encoding/json"
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"errors"
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"github.com/syndtr/goleveldb/leveldb"
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"github.com/syndtr/goleveldb/leveldb/storage"
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)
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// ErrNotFound is returned when no results are returned from the database
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var ErrNotFound = errors.New("ErrorNotFound")
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// Store defines methods required to get, set, delete values for different keys
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// and close the underlying resources.
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type Store interface {
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Get(key string, i interface{}) (err error)
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Put(key string, i interface{}) (err error)
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Delete(key string) (err error)
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Close() error
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}
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// DBStore uses LevelDB to store values.
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type DBStore struct {
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db *leveldb.DB
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}
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// NewDBStore creates a new instance of DBStore.
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func NewDBStore(path string) (s *DBStore, err error) {
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db, err := leveldb.OpenFile(path, nil)
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if err != nil {
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return nil, err
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}
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return &DBStore{
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db: db,
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}, nil
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}
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// NewInmemoryStore returns a new instance of DBStore. To be used only in tests and simulations.
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func NewInmemoryStore() *DBStore {
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db, err := leveldb.Open(storage.NewMemStorage(), nil)
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if err != nil {
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panic(err)
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}
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return &DBStore{
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db: db,
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}
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}
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// Get retrieves a persisted value for a specific key. If there is no results
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// ErrNotFound is returned. The provided parameter should be either a byte slice or
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// a struct that implements the encoding.BinaryUnmarshaler interface
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func (s *DBStore) Get(key string, i interface{}) (err error) {
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has, err := s.db.Has([]byte(key), nil)
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if err != nil || !has {
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return ErrNotFound
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}
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data, err := s.db.Get([]byte(key), nil)
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if err == leveldb.ErrNotFound {
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return ErrNotFound
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}
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unmarshaler, ok := i.(encoding.BinaryUnmarshaler)
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if !ok {
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return json.Unmarshal(data, i)
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}
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return unmarshaler.UnmarshalBinary(data)
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}
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// Put stores an object that implements Binary for a specific key.
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func (s *DBStore) Put(key string, i interface{}) (err error) {
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var bytes []byte
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marshaler, ok := i.(encoding.BinaryMarshaler)
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if !ok {
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if bytes, err = json.Marshal(i); err != nil {
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return err
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}
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} else {
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if bytes, err = marshaler.MarshalBinary(); err != nil {
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return err
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}
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}
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return s.db.Put([]byte(key), bytes, nil)
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}
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// Delete removes entries stored under a specific key.
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func (s *DBStore) Delete(key string) (err error) {
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return s.db.Delete([]byte(key), nil)
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}
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// Close releases the resources used by the underlying LevelDB.
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func (s *DBStore) Close() error {
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return s.db.Close()
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}
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