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86 lines
2.5 KiB
86 lines
2.5 KiB
// 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 storage
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import "errors"
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var (
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// ErrZeroKey is returned if an attempt was made to inset a 0-length key.
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ErrZeroKey = errors.New("0-length key")
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// ErrNotFound is returned if an unknown key is attempted to be retrieved.
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ErrNotFound = errors.New("not found")
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)
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type Storage interface {
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// Put stores a value by key. 0-length keys results in noop.
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Put(key, value string)
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// Get returns the previously stored value, or an error if the key is 0-length
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// or unknown.
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Get(key string) (string, error)
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// Del removes a key-value pair. If the key doesn't exist, the method is a noop.
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Del(key string)
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}
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// EphemeralStorage is an in-memory storage that does
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// not persist values to disk. Mainly used for testing
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type EphemeralStorage struct {
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data map[string]string
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}
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// Put stores a value by key. 0-length keys results in noop.
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func (s *EphemeralStorage) Put(key, value string) {
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if len(key) == 0 {
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return
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}
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s.data[key] = value
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}
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// Get returns the previously stored value, or an error if the key is 0-length
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// or unknown.
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func (s *EphemeralStorage) Get(key string) (string, error) {
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if len(key) == 0 {
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return "", ErrZeroKey
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}
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if v, ok := s.data[key]; ok {
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return v, nil
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}
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return "", ErrNotFound
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}
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// Del removes a key-value pair. If the key doesn't exist, the method is a noop.
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func (s *EphemeralStorage) Del(key string) {
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delete(s.data, key)
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}
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func NewEphemeralStorage() Storage {
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s := &EphemeralStorage{
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data: make(map[string]string),
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}
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return s
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}
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// NoStorage is a dummy construct which doesn't remember anything you tell it
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type NoStorage struct{}
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func (s *NoStorage) Put(key, value string) {}
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func (s *NoStorage) Del(key string) {}
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func (s *NoStorage) Get(key string) (string, error) {
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return "", errors.New("missing key, I probably forgot")
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}
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