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package db
import (
"encoding/binary"
"fmt"
"github.com/google/orderedcode"
dbm "github.com/tendermint/tm-db"
tmsync "github.com/tendermint/tendermint/internal/libs/sync"
"github.com/tendermint/tendermint/light/store"
tmproto "github.com/tendermint/tendermint/proto/tendermint/types"
"github.com/tendermint/tendermint/types"
)
const (
prefixLightBlock = int64(11)
prefixSize = int64(12)
)
type dbs struct {
db dbm.DB
mtx tmsync.RWMutex
size uint16
}
// New returns a Store that wraps any DB
// If you want to share one DB across many light clients consider using PrefixDB
func New(db dbm.DB) store.Store {
lightStore := &dbs{db: db}
// retrieve the size of the db
size := uint16(0)
bz, err := lightStore.db.Get(lightStore.sizeKey())
if err == nil && len(bz) > 0 {
size = unmarshalSize(bz)
}
lightStore.size = size
return lightStore
}
// SaveLightBlock persists LightBlock to the db.
//
// Safe for concurrent use by multiple goroutines.
func (s *dbs) SaveLightBlock(lb *types.LightBlock) error {
if lb.Height <= 0 {
panic("negative or zero height")
}
lbpb, err := lb.ToProto()
if err != nil {
return fmt.Errorf("unable to convert light block to protobuf: %w", err)
}
lbBz, err := lbpb.Marshal()
if err != nil {
return fmt.Errorf("marshaling LightBlock: %w", err)
}
s.mtx.Lock()
defer s.mtx.Unlock()
b := s.db.NewBatch()
defer b.Close()
if err = b.Set(s.lbKey(lb.Height), lbBz); err != nil {
return err
}
if err = b.Set(s.sizeKey(), marshalSize(s.size+1)); err != nil {
return err
}
if err = b.WriteSync(); err != nil {
return err
}
s.size++
return nil
}
// DeleteLightBlockAndValidatorSet deletes the LightBlock from
// the db.
//
// Safe for concurrent use by multiple goroutines.
func (s *dbs) DeleteLightBlock(height int64) error {
if height <= 0 {
panic("negative or zero height")
}
s.mtx.Lock()
defer s.mtx.Unlock()
b := s.db.NewBatch()
defer b.Close()
if err := b.Delete(s.lbKey(height)); err != nil {
return err
}
if err := b.Set(s.sizeKey(), marshalSize(s.size-1)); err != nil {
return err
}
if err := b.WriteSync(); err != nil {
return err
}
s.size--
return nil
}
// LightBlock retrieves the LightBlock at the given height.
//
// Safe for concurrent use by multiple goroutines.
func (s *dbs) LightBlock(height int64) (*types.LightBlock, error) {
if height <= 0 {
panic("negative or zero height")
}
bz, err := s.db.Get(s.lbKey(height))
if err != nil {
panic(err)
}
if len(bz) == 0 {
return nil, store.ErrLightBlockNotFound
}
var lbpb tmproto.LightBlock
err = lbpb.Unmarshal(bz)
if err != nil {
return nil, fmt.Errorf("unmarshal error: %w", err)
}
lightBlock, err := types.LightBlockFromProto(&lbpb)
if err != nil {
return nil, fmt.Errorf("proto conversion error: %w", err)
}
return lightBlock, err
}
// LastLightBlockHeight returns the last LightBlock height stored.
//
// Safe for concurrent use by multiple goroutines.
func (s *dbs) LastLightBlockHeight() (int64, error) {
itr, err := s.db.ReverseIterator(
s.lbKey(1),
append(s.lbKey(1<<63-1), byte(0x00)),
)
if err != nil {
panic(err)
}
defer itr.Close()
if itr.Valid() {
return s.decodeLbKey(itr.Key())
}
return -1, itr.Error()
}
// FirstLightBlockHeight returns the first LightBlock height stored.
//
// Safe for concurrent use by multiple goroutines.
func (s *dbs) FirstLightBlockHeight() (int64, error) {
itr, err := s.db.Iterator(
s.lbKey(1),
append(s.lbKey(1<<63-1), byte(0x00)),
)
if err != nil {
panic(err)
}
defer itr.Close()
if itr.Valid() {
return s.decodeLbKey(itr.Key())
}
return -1, itr.Error()
}
// LightBlockBefore iterates over light blocks until it finds a block before
// the given height. It returns ErrLightBlockNotFound if no such block exists.
//
// Safe for concurrent use by multiple goroutines.
func (s *dbs) LightBlockBefore(height int64) (*types.LightBlock, error) {
if height <= 0 {
panic("negative or zero height")
}
itr, err := s.db.ReverseIterator(
s.lbKey(1),
s.lbKey(height),
)
if err != nil {
panic(err)
}
defer itr.Close()
if itr.Valid() {
var lbpb tmproto.LightBlock
err = lbpb.Unmarshal(itr.Value())
if err != nil {
return nil, fmt.Errorf("unmarshal error: %w", err)
}
lightBlock, err := types.LightBlockFromProto(&lbpb)
if err != nil {
return nil, fmt.Errorf("proto conversion error: %w", err)
}
return lightBlock, nil
}
if err = itr.Error(); err != nil {
return nil, err
}
return nil, store.ErrLightBlockNotFound
}
// Prune prunes header & validator set pairs until there are only size pairs
// left.
//
// Safe for concurrent use by multiple goroutines.
func (s *dbs) Prune(size uint16) error {
// 1) Check how many we need to prune.
s.mtx.Lock()
defer s.mtx.Unlock()
sSize := s.size
if sSize <= size { // nothing to prune
return nil
}
numToPrune := sSize - size
b := s.db.NewBatch()
defer b.Close()
// 2) use an iterator to batch together all the blocks that need to be deleted
if err := s.batchDelete(b, numToPrune); err != nil {
return err
}
// 3) // update size
s.size = size
if err := b.Set(s.sizeKey(), marshalSize(size)); err != nil {
return fmt.Errorf("failed to persist size: %w", err)
}
// 4) write batch deletion to disk
return b.WriteSync()
}
// Size returns the number of header & validator set pairs.
//
// Safe for concurrent use by multiple goroutines.
func (s *dbs) Size() uint16 {
s.mtx.RLock()
defer s.mtx.RUnlock()
return s.size
}
func (s *dbs) batchDelete(batch dbm.Batch, numToPrune uint16) error {
itr, err := s.db.Iterator(
s.lbKey(1),
append(s.lbKey(1<<63-1), byte(0x00)),
)
if err != nil {
return err
}
defer itr.Close()
for itr.Valid() && numToPrune > 0 {
if err = batch.Delete(itr.Key()); err != nil {
return err
}
itr.Next()
numToPrune--
}
return itr.Error()
}
func (s *dbs) sizeKey() []byte {
key, err := orderedcode.Append(nil, prefixSize)
if err != nil {
panic(err)
}
return key
}
func (s *dbs) lbKey(height int64) []byte {
key, err := orderedcode.Append(nil, prefixLightBlock, height)
if err != nil {
panic(err)
}
return key
}
func (s *dbs) decodeLbKey(key []byte) (height int64, err error) {
var lightBlockPrefix int64
remaining, err := orderedcode.Parse(string(key), &lightBlockPrefix, &height)
if err != nil {
err = fmt.Errorf("failed to parse light block key: %w", err)
}
if len(remaining) != 0 {
err = fmt.Errorf("expected no remainder when parsing light block key but got: %s", remaining)
}
if lightBlockPrefix != prefixLightBlock {
err = fmt.Errorf("expected light block prefix but got: %d", lightBlockPrefix)
}
return
}
func marshalSize(size uint16) []byte {
bs := make([]byte, 2)
binary.LittleEndian.PutUint16(bs, size)
return bs
}
func unmarshalSize(bz []byte) uint16 {
return binary.LittleEndian.Uint16(bz)
}