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package db
import (
"encoding/binary"
"fmt"
"regexp"
"strconv"
dbm "github.com/tendermint/tm-db"
tmsync "github.com/tendermint/tendermint/libs/sync"
"github.com/tendermint/tendermint/light/store"
tmproto "github.com/tendermint/tendermint/proto/tendermint/types"
"github.com/tendermint/tendermint/types"
)
var (
sizeKey = []byte("size")
)
type dbs struct {
db dbm.DB
prefix string
mtx tmsync.RWMutex
size uint16
}
// New returns a Store that wraps any DB (with an optional prefix in case you
// want to use one DB with many light clients).
func New(db dbm.DB, prefix string) store.Store {
size := uint16(0)
bz, err := db.Get(sizeKey)
if err == nil && len(bz) > 0 {
size = unmarshalSize(bz)
}
return &dbs{db: db, prefix: prefix, size: size}
}
// 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("marshalling 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(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(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()
for itr.Valid() {
key := itr.Key()
_, height, ok := parseLbKey(key)
if ok {
return height, nil
}
itr.Next()
}
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()
for itr.Valid() {
key := itr.Key()
_, height, ok := parseLbKey(key)
if ok {
return height, nil
}
itr.Next()
}
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()
for itr.Valid() {
key := itr.Key()
_, existingHeight, ok := parseLbKey(key)
if ok {
return s.LightBlock(existingHeight)
}
itr.Next()
}
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.RLock()
sSize := s.size
s.mtx.RUnlock()
if sSize <= size { // nothing to prune
return nil
}
numToPrune := sSize - size
// 2) Iterate over headers and perform a batch operation.
itr, err := s.db.Iterator(
s.lbKey(1),
append(s.lbKey(1<<63-1), byte(0x00)),
)
if err != nil {
panic(err)
}
defer itr.Close()
b := s.db.NewBatch()
defer b.Close()
pruned := 0
for itr.Valid() && numToPrune > 0 {
key := itr.Key()
_, height, ok := parseLbKey(key)
if ok {
if err = b.Delete(s.lbKey(height)); err != nil {
return err
}
}
itr.Next()
numToPrune--
pruned++
}
if err = itr.Error(); err != nil {
return err
}
err = b.WriteSync()
if err != nil {
return err
}
// 3) Update size.
s.mtx.Lock()
defer s.mtx.Unlock()
s.size -= uint16(pruned)
if wErr := s.db.SetSync(sizeKey, marshalSize(s.size)); wErr != nil {
return fmt.Errorf("failed to persist size: %w", wErr)
}
return nil
}
// 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) lbKey(height int64) []byte {
return []byte(fmt.Sprintf("lb/%s/%020d", s.prefix, height))
}
var keyPattern = regexp.MustCompile(`^(lb)/([^/]*)/([0-9]+)$`)
func parseKey(key []byte) (part string, prefix string, height int64, ok bool) {
submatch := keyPattern.FindSubmatch(key)
if submatch == nil {
return "", "", 0, false
}
part = string(submatch[1])
prefix = string(submatch[2])
height, err := strconv.ParseInt(string(submatch[3]), 10, 64)
if err != nil {
return "", "", 0, false
}
ok = true // good!
return
}
func parseLbKey(key []byte) (prefix string, height int64, ok bool) {
var part string
part, prefix, height, ok = parseKey(key)
if part != "lb" {
return "", 0, false
}
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)
}