Official Go implementation of the Ethereum protocol
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go-ethereum/swarm/storage/mock/mem/mem.go

192 lines
4.8 KiB

// 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 mem implements a mock store that keeps all chunk data in memory.
// While it can be used for testing on smaller scales, the main purpose of this
// package is to provide the simplest reference implementation of a mock store.
package mem
import (
"archive/tar"
"bytes"
"encoding/json"
"io"
"io/ioutil"
"sync"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/swarm/storage/mock"
)
// GlobalStore stores all chunk data and also keys and node addresses relations.
// It implements mock.GlobalStore interface.
type GlobalStore struct {
nodes map[string]map[common.Address]struct{}
data map[string][]byte
mu sync.Mutex
}
// NewGlobalStore creates a new instance of GlobalStore.
func NewGlobalStore() *GlobalStore {
return &GlobalStore{
nodes: make(map[string]map[common.Address]struct{}),
data: make(map[string][]byte),
}
}
// NewNodeStore returns a new instance of NodeStore that retrieves and stores
// chunk data only for a node with address addr.
func (s *GlobalStore) NewNodeStore(addr common.Address) *mock.NodeStore {
return mock.NewNodeStore(addr, s)
}
// Get returns chunk data if the chunk with key exists for node
// on address addr.
func (s *GlobalStore) Get(addr common.Address, key []byte) (data []byte, err error) {
s.mu.Lock()
defer s.mu.Unlock()
if _, ok := s.nodes[string(key)][addr]; !ok {
return nil, mock.ErrNotFound
}
data, ok := s.data[string(key)]
if !ok {
return nil, mock.ErrNotFound
}
return data, nil
}
// Put saves the chunk data for node with address addr.
func (s *GlobalStore) Put(addr common.Address, key []byte, data []byte) error {
s.mu.Lock()
defer s.mu.Unlock()
if _, ok := s.nodes[string(key)]; !ok {
s.nodes[string(key)] = make(map[common.Address]struct{})
}
s.nodes[string(key)][addr] = struct{}{}
s.data[string(key)] = data
return nil
}
// Delete removes the chunk data for node with address addr.
func (s *GlobalStore) Delete(addr common.Address, key []byte) error {
s.mu.Lock()
defer s.mu.Unlock()
var count int
if _, ok := s.nodes[string(key)]; ok {
delete(s.nodes[string(key)], addr)
count = len(s.nodes[string(key)])
}
if count == 0 {
delete(s.data, string(key))
}
return nil
}
// HasKey returns whether a node with addr contains the key.
func (s *GlobalStore) HasKey(addr common.Address, key []byte) bool {
s.mu.Lock()
defer s.mu.Unlock()
_, ok := s.nodes[string(key)][addr]
return ok
}
// Import reads tar archive from a reader that contains exported chunk data.
// It returns the number of chunks imported and an error.
func (s *GlobalStore) Import(r io.Reader) (n int, err error) {
s.mu.Lock()
defer s.mu.Unlock()
tr := tar.NewReader(r)
for {
hdr, err := tr.Next()
if err != nil {
if err == io.EOF {
break
}
return n, err
}
data, err := ioutil.ReadAll(tr)
if err != nil {
return n, err
}
var c mock.ExportedChunk
if err = json.Unmarshal(data, &c); err != nil {
return n, err
}
addrs := make(map[common.Address]struct{})
for _, a := range c.Addrs {
addrs[a] = struct{}{}
}
key := string(common.Hex2Bytes(hdr.Name))
s.nodes[key] = addrs
s.data[key] = c.Data
n++
}
return n, err
}
// Export writes to a writer a tar archive with all chunk data from
// the store. It returns the number of chunks exported and an error.
func (s *GlobalStore) Export(w io.Writer) (n int, err error) {
s.mu.Lock()
defer s.mu.Unlock()
tw := tar.NewWriter(w)
defer tw.Close()
buf := bytes.NewBuffer(make([]byte, 0, 1024))
encoder := json.NewEncoder(buf)
for key, addrs := range s.nodes {
al := make([]common.Address, 0, len(addrs))
for a := range addrs {
al = append(al, a)
}
buf.Reset()
if err = encoder.Encode(mock.ExportedChunk{
Addrs: al,
Data: s.data[key],
}); err != nil {
return n, err
}
data := buf.Bytes()
hdr := &tar.Header{
Name: common.Bytes2Hex([]byte(key)),
Mode: 0644,
Size: int64(len(data)),
}
if err := tw.WriteHeader(hdr); err != nil {
return n, err
}
if _, err := tw.Write(data); err != nil {
return n, err
}
n++
}
return n, err
}