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- // Copyright 2018 The go-ethereum Authors
- // This file is part of the go-ethereum library.
- //
- // The go-ethereum library is free software: you can redistribute it and/or modify
- // it under the terms of the GNU Lesser General Public License as published by
- // the Free Software Foundation, either version 3 of the License, or
- // (at your option) any later version.
- //
- // The go-ethereum library is distributed in the hope that it will be useful,
- // but WITHOUT ANY WARRANTY; without even the implied warranty of
- // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- // GNU Lesser General Public License for more details.
- //
- // You should have received a copy of the GNU Lesser General Public License
- // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
- package storage
- import "errors"
- var (
- // ErrZeroKey is returned if an attempt was made to inset a 0-length key.
- ErrZeroKey = errors.New("0-length key")
- // ErrNotFound is returned if an unknown key is attempted to be retrieved.
- ErrNotFound = errors.New("not found")
- )
- type Storage interface {
- // Put stores a value by key. 0-length keys results in noop.
- Put(key, value string)
- // Get returns the previously stored value, or an error if the key is 0-length
- // or unknown.
- Get(key string) (string, error)
- // Del removes a key-value pair. If the key doesn't exist, the method is a noop.
- Del(key string)
- }
- // EphemeralStorage is an in-memory storage that does
- // not persist values to disk. Mainly used for testing
- type EphemeralStorage struct {
- data map[string]string
- }
- // Put stores a value by key. 0-length keys results in noop.
- func (s *EphemeralStorage) Put(key, value string) {
- if len(key) == 0 {
- return
- }
- s.data[key] = value
- }
- // Get returns the previously stored value, or an error if the key is 0-length
- // or unknown.
- func (s *EphemeralStorage) Get(key string) (string, error) {
- if len(key) == 0 {
- return "", ErrZeroKey
- }
- if v, ok := s.data[key]; ok {
- return v, nil
- }
- return "", ErrNotFound
- }
- // Del removes a key-value pair. If the key doesn't exist, the method is a noop.
- func (s *EphemeralStorage) Del(key string) {
- delete(s.data, key)
- }
- func NewEphemeralStorage() Storage {
- s := &EphemeralStorage{
- data: make(map[string]string),
- }
- return s
- }
- // NoStorage is a dummy construct which doesn't remember anything you tell it
- type NoStorage struct{}
- func (s *NoStorage) Put(key, value string) {}
- func (s *NoStorage) Del(key string) {}
- func (s *NoStorage) Get(key string) (string, error) {
- return "", errors.New("missing key, I probably forgot")
- }
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