// 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 db implements a mock store that keeps all chunk data in LevelDB database.
package db
import (
"archive/tar"
"bytes"
"encoding/json"
"io"
"io/ioutil"
"github.com/syndtr/goleveldb/leveldb"
"github.com/syndtr/goleveldb/leveldb/util"
"github.com/dexon-foundation/dexon/common"
"github.com/dexon-foundation/dexon/swarm/storage/mock"
)
// GlobalStore contains the LevelDB database that is storing
// chunk data for all swarm nodes.
// Closing the GlobalStore with Close method is required to
// release resources used by the database.
type GlobalStore struct {
db *leveldb.DB
}
// NewGlobalStore creates a new instance of GlobalStore.
func NewGlobalStore(path string) (s *GlobalStore, err error) {
db, err := leveldb.OpenFile(path, nil)
if err != nil {
return nil, err
}
return &GlobalStore{
db: db,
}, nil
}
// Close releases the resources used by the underlying LevelDB.
func (s *GlobalStore) Close() error {
return s.db.Close()
}
// 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) {
has, err := s.db.Has(nodeDBKey(addr, key), nil)
if err != nil {
return nil, mock.ErrNotFound
}
if !has {
return nil, mock.ErrNotFound
}
data, err = s.db.Get(dataDBKey(key), nil)
if err == leveldb.ErrNotFound {
err = mock.ErrNotFound
}
return
}
// Put saves the chunk data for node with address addr.
func (s *GlobalStore) Put(addr common.Address, key []byte, data []byte) error {
batch := new(leveldb.Batch)
batch.Put(nodeDBKey(addr, key), nil)
batch.Put(dataDBKey(key), data)
return s.db.Write(batch, nil)
}
// Delete removes the chunk reference to node with address addr.
func (s *GlobalStore) Delete(addr common.Address, key []byte) error {
batch := new(leveldb.Batch)
batch.Delete(nodeDBKey(addr, key))
return s.db.Write(batch, nil)
}
// HasKey returns whether a node with addr contains the key.
func (s *GlobalStore) HasKey(addr common.Address, key []byte) bool {
has, err := s.db.Has(nodeDBKey(addr, key), nil)
if err != nil {
has = false
}
return has
}
// 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) {
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
}
batch := new(leveldb.Batch)
for _, addr := range c.Addrs {
batch.Put(nodeDBKeyHex(addr, hdr.Name), nil)
}
batch.Put(dataDBKey(common.Hex2Bytes(hdr.Name)), c.Data)
if err = s.db.Write(batch, nil); err != nil {
return n, err
}
n++
}
return n, err
}
// Export writes to a writer a tar archive with all chunk data from
// the store. It returns the number fo chunks exported and an error.
func (s *GlobalStore) Export(w io.Writer) (n int, err error) {
tw := tar.NewWriter(w)
defer tw.Close()
buf := bytes.NewBuffer(make([]byte, 0, 1024))
encoder := json.NewEncoder(buf)
iter := s.db.NewIterator(util.BytesPrefix(nodeKeyPrefix), nil)
defer iter.Release()
var currentKey string
var addrs []common.Address
saveChunk := func(hexKey string) error {
key := common.Hex2Bytes(hexKey)
data, err := s.db.Get(dataDBKey(key), nil)
if err != nil {
return err
}
buf.Reset()
if err = encoder.Encode(mock.ExportedChunk{
Addrs: addrs,
Data: data,
}); err != nil {
return err
}
d := buf.Bytes()
hdr := &tar.Header{
Name: hexKey,
Mode: 0644,
Size: int64(len(d)),
}
if err := tw.WriteHeader(hdr); err != nil {
return err
}
if _, err := tw.Write(d); err != nil {
return err
}
n++
return nil
}
for iter.Next() {
k := bytes.TrimPrefix(iter.Key(), nodeKeyPrefix)
i := bytes.Index(k, []byte("-"))
if i < 0 {
continue
}
hexKey := string(k[:i])
if currentKey == "" {
currentKey = hexKey
}
if hexKey != currentKey {
if err = saveChunk(currentKey); err != nil {
return n, err
}
addrs = addrs[:0]
}
currentKey = hexKey
addrs = append(addrs, common.BytesToAddress(k[i:]))
}
if len(addrs) > 0 {
if err = saveChunk(currentKey); err != nil {
return n, err
}
}
return n, err
}
var (
nodeKeyPrefix = []byte("node-")
dataKeyPrefix = []byte("data-")
)
// nodeDBKey constructs a database key for key/node mappings.
func nodeDBKey(addr common.Address, key []byte) []byte {
return nodeDBKeyHex(addr, common.Bytes2Hex(key))
}
// nodeDBKeyHex constructs a database key for key/node mappings
// using the hexadecimal string representation of the key.
func nodeDBKeyHex(addr common.Address, hexKey string) []byte {
return append(append(nodeKeyPrefix, []byte(hexKey+"-")...), addr[:]...)
}
// dataDBkey constructs a database key for key/data storage.
func dataDBKey(key []byte) []byte {
return append(dataKeyPrefix, key...)
}
