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

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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 db implements a mock store that keeps all chunk data in LevelDB database.
package db
import (
"archive/tar"
"bytes"
"encoding/json"
"errors"
"fmt"
"io"
"io/ioutil"
"sync"
"time"
"github.com/syndtr/goleveldb/leveldb"
"github.com/syndtr/goleveldb/leveldb/util"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/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
// protects nodes and keys indexes
// in Put and Delete methods
nodesLocks sync.Map
keysLocks sync.Map
}
// 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(indexForHashesPerNode(addr, key), nil)
if err != nil {
return nil, mock.ErrNotFound
}
if !has {
return nil, mock.ErrNotFound
}
data, err = s.db.Get(indexDataKey(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 {
unlock, err := s.lock(addr, key)
if err != nil {
return err
}
defer unlock()
batch := new(leveldb.Batch)
batch.Put(indexForHashesPerNode(addr, key), nil)
batch.Put(indexForNodesWithHash(key, addr), nil)
batch.Put(indexForNodes(addr), nil)
batch.Put(indexForHashes(key), nil)
batch.Put(indexDataKey(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 {
unlock, err := s.lock(addr, key)
if err != nil {
return err
}
defer unlock()
batch := new(leveldb.Batch)
batch.Delete(indexForHashesPerNode(addr, key))
batch.Delete(indexForNodesWithHash(key, addr))
// check if this node contains any keys, and if not
// remove it from the
x := indexForHashesPerNodePrefix(addr)
if k, _ := s.db.Get(x, nil); !bytes.HasPrefix(k, x) {
batch.Delete(indexForNodes(addr))
}
x = indexForNodesWithHashPrefix(key)
if k, _ := s.db.Get(x, nil); !bytes.HasPrefix(k, x) {
batch.Delete(indexForHashes(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(indexForHashesPerNode(addr, key), nil)
if err != nil {
has = false
}
return has
}
// Keys returns a paginated list of keys on all nodes.
func (s *GlobalStore) Keys(startKey []byte, limit int) (keys mock.Keys, err error) {
return s.keys(nil, startKey, limit)
}
// Nodes returns a paginated list of all known nodes.
func (s *GlobalStore) Nodes(startAddr *common.Address, limit int) (nodes mock.Nodes, err error) {
return s.nodes(nil, startAddr, limit)
}
// NodeKeys returns a paginated list of keys on a node with provided address.
func (s *GlobalStore) NodeKeys(addr common.Address, startKey []byte, limit int) (keys mock.Keys, err error) {
return s.keys(&addr, startKey, limit)
}
// KeyNodes returns a paginated list of nodes that contain a particular key.
func (s *GlobalStore) KeyNodes(key []byte, startAddr *common.Address, limit int) (nodes mock.Nodes, err error) {
return s.nodes(key, startAddr, limit)
}
// keys returns a paginated list of keys. If addr is not nil, only keys on that
// node will be returned.
func (s *GlobalStore) keys(addr *common.Address, startKey []byte, limit int) (keys mock.Keys, err error) {
iter := s.db.NewIterator(nil, nil)
defer iter.Release()
if limit <= 0 {
limit = mock.DefaultLimit
}
prefix := []byte{indexForHashesPrefix}
if addr != nil {
prefix = indexForHashesPerNodePrefix(*addr)
}
if startKey != nil {
if addr != nil {
startKey = indexForHashesPerNode(*addr, startKey)
} else {
startKey = indexForHashes(startKey)
}
} else {
startKey = prefix
}
ok := iter.Seek(startKey)
if !ok {
return keys, iter.Error()
}
for ; ok; ok = iter.Next() {
k := iter.Key()
if !bytes.HasPrefix(k, prefix) {
break
}
key := append([]byte(nil), bytes.TrimPrefix(k, prefix)...)
if len(keys.Keys) >= limit {
keys.Next = key
break
}
keys.Keys = append(keys.Keys, key)
}
return keys, iter.Error()
}
// nodes returns a paginated list of node addresses. If key is not nil,
// only nodes that contain that key will be returned.
func (s *GlobalStore) nodes(key []byte, startAddr *common.Address, limit int) (nodes mock.Nodes, err error) {
iter := s.db.NewIterator(nil, nil)
defer iter.Release()
if limit <= 0 {
limit = mock.DefaultLimit
}
prefix := []byte{indexForNodesPrefix}
if key != nil {
prefix = indexForNodesWithHashPrefix(key)
}
startKey := prefix
if startAddr != nil {
if key != nil {
startKey = indexForNodesWithHash(key, *startAddr)
} else {
startKey = indexForNodes(*startAddr)
}
}
ok := iter.Seek(startKey)
if !ok {
return nodes, iter.Error()
}
for ; ok; ok = iter.Next() {
k := iter.Key()
if !bytes.HasPrefix(k, prefix) {
break
}
addr := common.BytesToAddress(append([]byte(nil), bytes.TrimPrefix(k, prefix)...))
if len(nodes.Addrs) >= limit {
nodes.Next = &addr
break
}
nodes.Addrs = append(nodes.Addrs, addr)
}
return nodes, iter.Error()
}
// 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
}
key := common.Hex2Bytes(hdr.Name)
batch := new(leveldb.Batch)
for _, addr := range c.Addrs {
batch.Put(indexForHashesPerNode(addr, key), nil)
batch.Put(indexForNodesWithHash(key, addr), nil)
batch.Put(indexForNodes(addr), nil)
}
batch.Put(indexForHashes(key), nil)
batch.Put(indexDataKey(key), 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)
snap, err := s.db.GetSnapshot()
if err != nil {
return 0, err
}
iter := snap.NewIterator(util.BytesPrefix([]byte{indexForHashesByNodePrefix}), nil)
defer iter.Release()
var currentKey string
var addrs []common.Address
saveChunk := func() error {
hexKey := currentKey
data, err := snap.Get(indexDataKey(common.Hex2Bytes(hexKey)), nil)
if err != nil {
return fmt.Errorf("get data %s: %v", hexKey, 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(), []byte{indexForHashesByNodePrefix})
i := bytes.Index(k, []byte{keyTermByte})
if i < 0 {
continue
}
hexKey := string(k[:i])
if currentKey == "" {
currentKey = hexKey
}
if hexKey != currentKey {
if err = saveChunk(); err != nil {
return n, err
}
addrs = addrs[:0]
}
currentKey = hexKey
addrs = append(addrs, common.BytesToAddress(k[i+1:]))
}
if len(addrs) > 0 {
if err = saveChunk(); err != nil {
return n, err
}
}
return n, iter.Error()
}
var (
// maximal time for lock to wait until it returns error
lockTimeout = 3 * time.Second
// duration between two lock checks.
lockCheckDelay = 30 * time.Microsecond
// error returned by lock method when lock timeout is reached
errLockTimeout = errors.New("lock timeout")
)
// lock protects parallel writes in Put and Delete methods for both
// node with provided address and for data with provided key.
func (s *GlobalStore) lock(addr common.Address, key []byte) (unlock func(), err error) {
start := time.Now()
nodeLockKey := addr.Hex()
for {
_, loaded := s.nodesLocks.LoadOrStore(nodeLockKey, struct{}{})
if !loaded {
break
}
time.Sleep(lockCheckDelay)
if time.Since(start) > lockTimeout {
return nil, errLockTimeout
}
}
start = time.Now()
keyLockKey := common.Bytes2Hex(key)
for {
_, loaded := s.keysLocks.LoadOrStore(keyLockKey, struct{}{})
if !loaded {
break
}
time.Sleep(lockCheckDelay)
if time.Since(start) > lockTimeout {
return nil, errLockTimeout
}
}
return func() {
s.nodesLocks.Delete(nodeLockKey)
s.keysLocks.Delete(keyLockKey)
}, nil
}
const (
// prefixes for different indexes
indexDataPrefix = 0
indexForNodesWithHashesPrefix = 1
indexForHashesByNodePrefix = 2
indexForNodesPrefix = 3
indexForHashesPrefix = 4
// keyTermByte splits keys and node addresses
// in database keys
keyTermByte = 0xff
)
// indexForHashesPerNode constructs a database key to store keys used in
// NodeKeys method.
func indexForHashesPerNode(addr common.Address, key []byte) []byte {
return append(indexForHashesPerNodePrefix(addr), key...)
}
// indexForHashesPerNodePrefix returns a prefix containing a node address used in
// NodeKeys method. Node address is hex encoded to be able to use keyTermByte
// for splitting node address and key.
func indexForHashesPerNodePrefix(addr common.Address) []byte {
return append([]byte{indexForNodesWithHashesPrefix}, append([]byte(addr.Hex()), keyTermByte)...)
}
// indexForNodesWithHash constructs a database key to store keys used in
// KeyNodes method.
func indexForNodesWithHash(key []byte, addr common.Address) []byte {
return append(indexForNodesWithHashPrefix(key), addr[:]...)
}
// indexForNodesWithHashPrefix returns a prefix containing a key used in
// KeyNodes method. Key is hex encoded to be able to use keyTermByte
// for splitting key and node address.
func indexForNodesWithHashPrefix(key []byte) []byte {
return append([]byte{indexForHashesByNodePrefix}, append([]byte(common.Bytes2Hex(key)), keyTermByte)...)
}
// indexForNodes constructs a database key to store keys used in
// Nodes method.
func indexForNodes(addr common.Address) []byte {
return append([]byte{indexForNodesPrefix}, addr[:]...)
}
// indexForHashes constructs a database key to store keys used in
// Keys method.
func indexForHashes(key []byte) []byte {
return append([]byte{indexForHashesPrefix}, key...)
}
// indexDataKey constructs a database key for key/data storage.
func indexDataKey(key []byte) []byte {
return append([]byte{indexDataPrefix}, key...)
}