// Copyright 2016 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 (
"bytes"
"context"
"crypto"
"crypto/rand"
"encoding/binary"
"fmt"
"io"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/swarm/bmt"
ch "github.com/ethereum/go-ethereum/swarm/chunk"
"golang.org/x/crypto/sha3"
)
const MaxPO = 16
const AddressLength = 32
type SwarmHasher func() SwarmHash
type Address []byte
// Proximity(x, y) returns the proximity order of the MSB distance between x and y
//
// The distance metric MSB(x, y) of two equal length byte sequences x an y is the
// value of the binary integer cast of the x^y, ie., x and y bitwise xor-ed.
// the binary cast is big endian: most significant bit first (=MSB).
//
// Proximity(x, y) is a discrete logarithmic scaling of the MSB distance.
// It is defined as the reverse rank of the integer part of the base 2
// logarithm of the distance.
// It is calculated by counting the number of common leading zeros in the (MSB)
// binary representation of the x^y.
//
// (0 farthest, 255 closest, 256 self)
func Proximity(one, other []byte) (ret int) {
b := (MaxPO-1)/8 + 1
if b > len(one) {
b = len(one)
}
m := 8
for i := 0; i < b; i++ {
oxo := one[i] ^ other[i]
for j := 0; j < m; j++ {
if (oxo>>uint8(7-j))&0x01 != 0 {
return i*8 + j
}
}
}
return MaxPO
}
var ZeroAddr = Address(common.Hash{}.Bytes())
func MakeHashFunc(hash string) SwarmHasher {
switch hash {
case "SHA256":
return func() SwarmHash { return &HashWithLength{crypto.SHA256.New()} }
case "SHA3":
return func() SwarmHash { return &HashWithLength{sha3.NewLegacyKeccak256()} }
case "BMT":
return func() SwarmHash {
hasher := sha3.NewLegacyKeccak256
hasherSize := hasher().Size()
segmentCount := ch.DefaultSize / hasherSize
pool := bmt.NewTreePool(hasher, segmentCount, bmt.PoolSize)
return bmt.New(pool)
}
}
return nil
}
func (a Address) Hex() string {
return fmt.Sprintf("%064x", []byte(a[:]))
}
func (a Address) Log() string {
if len(a[:]) < 8 {
return fmt.Sprintf("%x", []byte(a[:]))
}
return fmt.Sprintf("%016x", []byte(a[:8]))
}
func (a Address) String() string {
return fmt.Sprintf("%064x", []byte(a))
}
func (a Address) MarshalJSON() (out []byte, err error) {
return []byte(`"` + a.String() + `"`), nil
}
func (a *Address) UnmarshalJSON(value []byte) error {
s := string(value)
*a = make([]byte, 32)
h := common.Hex2Bytes(s[1 : len(s)-1])
copy(*a, h)
return nil
}
type AddressCollection []Address
func NewAddressCollection(l int) AddressCollection {
return make(AddressCollection, l)
}
func (c AddressCollection) Len() int {
return len(c)
}
func (c AddressCollection) Less(i, j int) bool {
return bytes.Compare(c[i], c[j]) == -1
}
func (c AddressCollection) Swap(i, j int) {
c[i], c[j] = c[j], c[i]
}
// Chunk interface implemented by context.Contexts and data chunks
type Chunk interface {
Address() Address
Data() []byte
}
type chunk struct {
addr Address
sdata []byte
span int64
}
func NewChunk(addr Address, data []byte) *chunk {
return &chunk{
addr: addr,
sdata: data,
span: -1,
}
}
func (c *chunk) Address() Address {
return c.addr
}
func (c *chunk) Data() []byte {
return c.sdata
}
// String() for pretty printing
func (self *chunk) String() string {
return fmt.Sprintf("Address: %v TreeSize: %v Chunksize: %v", self.addr.Log(), self.span, len(self.sdata))
}
func GenerateRandomChunk(dataSize int64) Chunk {
hasher := MakeHashFunc(DefaultHash)()
sdata := make([]byte, dataSize+8)
rand.Read(sdata[8:])
binary.LittleEndian.PutUint64(sdata[:8], uint64(dataSize))
hasher.ResetWithLength(sdata[:8])
hasher.Write(sdata[8:])
return NewChunk(hasher.Sum(nil), sdata)
}
func GenerateRandomChunks(dataSize int64, count int) (chunks []Chunk) {
for i := 0; i < count; i++ {
ch := GenerateRandomChunk(dataSize)
chunks = append(chunks, ch)
}
return chunks
}
// Size, Seek, Read, ReadAt
type LazySectionReader interface {
Context() context.Context
Size(context.Context, chan bool) (int64, error)
io.Seeker
io.Reader
io.ReaderAt
}
type LazyTestSectionReader struct {
*io.SectionReader
}
func (r *LazyTestSectionReader) Size(context.Context, chan bool) (int64, error) {
return r.SectionReader.Size(), nil
}
func (r *LazyTestSectionReader) Context() context.Context {
return context.TODO()
}
type StoreParams struct {
Hash SwarmHasher `toml:"-"`
DbCapacity uint64
CacheCapacity uint
BaseKey []byte
}
func NewDefaultStoreParams() *StoreParams {
return NewStoreParams(defaultLDBCapacity, defaultCacheCapacity, nil, nil)
}
func NewStoreParams(ldbCap uint64, cacheCap uint, hash SwarmHasher, basekey []byte) *StoreParams {
if basekey == nil {
basekey = make([]byte, 32)
}
if hash == nil {
hash = MakeHashFunc(DefaultHash)
}
return &StoreParams{
Hash: hash,
DbCapacity: ldbCap,
CacheCapacity: cacheCap,
BaseKey: basekey,
}
}
type ChunkData []byte
type Reference []byte
// Putter is responsible to store data and create a reference for it
type Putter interface {
Put(context.Context, ChunkData) (Reference, error)
// RefSize returns the length of the Reference created by this Putter
RefSize() int64
// Close is to indicate that no more chunk data will be Put on this Putter
Close()
// Wait returns if all data has been store and the Close() was called.
Wait(context.Context) error
}
// Getter is an interface to retrieve a chunk's data by its reference
type Getter interface {
Get(context.Context, Reference) (ChunkData, error)
}
// NOTE: this returns invalid data if chunk is encrypted
func (c ChunkData) Size() uint64 {
return binary.LittleEndian.Uint64(c[:8])
}
type ChunkValidator interface {
Validate(chunk Chunk) bool
}
// Provides method for validation of content address in chunks
// Holds the corresponding hasher to create the address
type ContentAddressValidator struct {
Hasher SwarmHasher
}
// Constructor
func NewContentAddressValidator(hasher SwarmHasher) *ContentAddressValidator {
return &ContentAddressValidator{
Hasher: hasher,
}
}
// Validate that the given key is a valid content address for the given data
func (v *ContentAddressValidator) Validate(chunk Chunk) bool {
data := chunk.Data()
if l := len(data); l < 9 || l > ch.DefaultSize+8 {
// log.Error("invalid chunk size", "chunk", addr.Hex(), "size", l)
return false
}
hasher := v.Hasher()
hasher.ResetWithLength(data[:8])
hasher.Write(data[8:])
hash := hasher.Sum(nil)
return bytes.Equal(hash, chunk.Address())
}
type ChunkStore interface {
Put(ctx context.Context, ch Chunk) (err error)
Get(rctx context.Context, ref Address) (ch Chunk, err error)
Has(rctx context.Context, ref Address) bool
Close()
}
// SyncChunkStore is a ChunkStore which supports syncing
type SyncChunkStore interface {
ChunkStore
BinIndex(po uint8) uint64
Iterator(from uint64, to uint64, po uint8, f func(Address, uint64) bool) error
FetchFunc(ctx context.Context, ref Address) func(context.Context) error
}
// FakeChunkStore doesn't store anything, just implements the ChunkStore interface
// It can be used to inject into a hasherStore if you don't want to actually store data just do the
// hashing
type FakeChunkStore struct {
}
// Put doesn't store anything it is just here to implement ChunkStore
func (f *FakeChunkStore) Put(_ context.Context, ch Chunk) error {
return nil
}
// Has doesn't do anything it is just here to implement ChunkStore
func (f *FakeChunkStore) Has(_ context.Context, ref Address) bool {
panic("FakeChunkStore doesn't support HasChunk")
}
// Get doesn't store anything it is just here to implement ChunkStore
func (f *FakeChunkStore) Get(_ context.Context, ref Address) (Chunk, error) {
panic("FakeChunkStore doesn't support Get")
}
// Close doesn't store anything it is just here to implement ChunkStore
func (f *FakeChunkStore) Close() {
}
