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package types
import (
"bytes"
"crypto/sha256"
"errors"
"fmt"
"io"
"strings"
"sync"
. "github.com/tendermint/tendermint/common"
"github.com/tendermint/tendermint/merkle"
)
const (
partSize = 4096 // 4KB
)
var (
ErrPartSetUnexpectedIndex = errors.New("Error part set unexpected index")
ErrPartSetInvalidTrail = errors.New("Error part set invalid trail")
)
type Part struct {
Index uint
Trail [][]byte
Bytes []byte
// Cache
hash []byte
}
func (part *Part) Hash() []byte {
if part.hash != nil {
return part.hash
} else {
hasher := sha256.New()
_, err := hasher.Write(part.Bytes)
if err != nil {
panic(err)
}
part.hash = hasher.Sum(nil)
return part.hash
}
}
func (part *Part) String() string {
return part.StringIndented("")
}
func (part *Part) StringIndented(indent string) string {
trailStrings := make([]string, len(part.Trail))
for i, hash := range part.Trail {
trailStrings[i] = fmt.Sprintf("%X", hash)
}
return fmt.Sprintf(`Part{
%s Index: %v
%s Trail:
%s %v
%s}`,
indent, part.Index,
indent,
indent, strings.Join(trailStrings, "\n"+indent+" "),
indent)
}
//-------------------------------------
type PartSetHeader struct {
Total uint
Hash []byte
}
func (psh PartSetHeader) String() string {
return fmt.Sprintf("PartSet{T:%v %X}", psh.Total, Fingerprint(psh.Hash))
}
func (psh PartSetHeader) IsZero() bool {
return psh.Total == 0
}
func (psh PartSetHeader) Equals(other PartSetHeader) bool {
return psh.Total == other.Total && bytes.Equal(psh.Hash, other.Hash)
}
//-------------------------------------
type PartSet struct {
total uint
hash []byte
mtx sync.Mutex
parts []*Part
partsBitArray BitArray
count uint
}
// Returns an immutable, full PartSet from the data bytes.
// The data bytes are split into "partSize" chunks, and merkle tree computed.
func NewPartSetFromData(data []byte) *PartSet {
// divide data into 4kb parts.
total := (len(data) + partSize - 1) / partSize
parts := make([]*Part, total)
parts_ := make([]merkle.Hashable, total)
partsBitArray := NewBitArray(uint(total))
for i := 0; i < total; i++ {
part := &Part{
Index: uint(i),
Bytes: data[i*partSize : MinInt(len(data), (i+1)*partSize)],
}
parts[i] = part
parts_[i] = part
partsBitArray.SetIndex(uint(i), true)
}
// Compute merkle trails
trails, rootTrail := merkle.HashTrailsFromHashables(parts_)
for i := 0; i < total; i++ {
parts[i].Trail = trails[i].Flatten()
}
return &PartSet{
total: uint(total),
hash: rootTrail.Hash,
parts: parts,
partsBitArray: partsBitArray,
count: uint(total),
}
}
// Returns an empty PartSet ready to be populated.
func NewPartSetFromHeader(header PartSetHeader) *PartSet {
return &PartSet{
total: header.Total,
hash: header.Hash,
parts: make([]*Part, header.Total),
partsBitArray: NewBitArray(uint(header.Total)),
count: 0,
}
}
func (ps *PartSet) Header() PartSetHeader {
if ps == nil {
return PartSetHeader{}
} else {
return PartSetHeader{
Total: ps.total,
Hash: ps.hash,
}
}
}
func (ps *PartSet) HasHeader(header PartSetHeader) bool {
if ps == nil {
return false
} else {
return ps.Header().Equals(header)
}
}
func (ps *PartSet) BitArray() BitArray {
ps.mtx.Lock()
defer ps.mtx.Unlock()
return ps.partsBitArray.Copy()
}
func (ps *PartSet) Hash() []byte {
if ps == nil {
return nil
}
return ps.hash
}
func (ps *PartSet) HashesTo(hash []byte) bool {
if ps == nil {
return false
}
return bytes.Equal(ps.hash, hash)
}
func (ps *PartSet) Count() uint {
if ps == nil {
return 0
}
return ps.count
}
func (ps *PartSet) Total() uint {
if ps == nil {
return 0
}
return ps.total
}
func (ps *PartSet) AddPart(part *Part) (bool, error) {
ps.mtx.Lock()
defer ps.mtx.Unlock()
// Invalid part index
if part.Index >= ps.total {
return false, ErrPartSetUnexpectedIndex
}
// If part already exists, return false.
if ps.parts[part.Index] != nil {
return false, nil
}
// Check hash trail
if !merkle.VerifyHashTrail(uint(part.Index), uint(ps.total), part.Hash(), part.Trail, ps.hash) {
return false, ErrPartSetInvalidTrail
}
// Add part
ps.parts[part.Index] = part
ps.partsBitArray.SetIndex(uint(part.Index), true)
ps.count++
return true, nil
}
func (ps *PartSet) GetPart(index uint) *Part {
ps.mtx.Lock()
defer ps.mtx.Unlock()
return ps.parts[index]
}
func (ps *PartSet) IsComplete() bool {
return ps.count == ps.total
}
func (ps *PartSet) GetReader() io.Reader {
if !ps.IsComplete() {
panic("Cannot GetReader() on incomplete PartSet")
}
buf := []byte{}
for _, part := range ps.parts {
buf = append(buf, part.Bytes...)
}
return bytes.NewReader(buf)
}
func (ps *PartSet) StringShort() string {
if ps == nil {
return "nil-PartSet"
} else {
return fmt.Sprintf("(%v of %v)", ps.Count(), ps.Total())
}
}