fix prefixIterator

This commit is contained in:
mossid 2018-09-05 21:48:32 -07:00
parent 7c9048b591
commit 5237639138
2 changed files with 174 additions and 21 deletions

View File

@ -1,6 +1,7 @@
package store
import (
"bytes"
"io"
sdk "github.com/cosmos/cosmos-sdk/types"
@ -13,6 +14,18 @@ type prefixStore struct {
prefix []byte
}
func clone(bz []byte) (res []byte) {
res = make([]byte, len(bz))
copy(res, bz)
return
}
func (s prefixStore) key(key []byte) (res []byte) {
res = clone(s.prefix)
res = append(res, key...)
return
}
// Implements Store
func (s prefixStore) GetStoreType() StoreType {
return s.parent.GetStoreType()
@ -30,22 +43,23 @@ func (s prefixStore) CacheWrapWithTrace(w io.Writer, tc TraceContext) CacheWrap
// Implements KVStore
func (s prefixStore) Get(key []byte) []byte {
return s.parent.Get(append(s.prefix, key...))
res := s.parent.Get(s.key(key))
return res
}
// Implements KVStore
func (s prefixStore) Has(key []byte) bool {
return s.parent.Has(append(s.prefix, key...))
return s.parent.Has(s.key(key))
}
// Implements KVStore
func (s prefixStore) Set(key, value []byte) {
s.parent.Set(append(s.prefix, key...), value)
s.parent.Set(s.key(key), value)
}
// Implements KVStore
func (s prefixStore) Delete(key []byte) {
s.parent.Delete(append(s.prefix, key...))
s.parent.Delete(s.key(key))
}
// Implements KVStore
@ -59,53 +73,83 @@ func (s prefixStore) Gas(meter GasMeter, config GasConfig) KVStore {
}
// Implements KVStore
// Check https://github.com/tendermint/tendermint/blob/master/libs/db/prefix_db.go#L106
func (s prefixStore) Iterator(start, end []byte) Iterator {
newstart := append(clone(s.prefix), start...)
var newend []byte
if end == nil {
end = sdk.PrefixEndBytes(s.prefix)
newend = cpIncr(s.prefix)
} else {
end = append(s.prefix, end...)
newend = append(clone(s.prefix), end...)
}
return prefixIterator{
prefix: s.prefix,
iter: s.parent.Iterator(append(s.prefix, start...), end),
start: newstart,
end: newend,
iter: s.parent.Iterator(newstart, newend),
}
}
// Implements KVStore
// Check https://github.com/tendermint/tendermint/blob/master/libs/db/prefix_db.go#L129
func (s prefixStore) ReverseIterator(start, end []byte) Iterator {
if end == nil {
end = sdk.PrefixEndBytes(s.prefix)
var newstart []byte
if start == nil {
newstart = cpIncr(s.prefix)
} else {
end = append(s.prefix, end...)
newstart = append(clone(s.prefix), start...)
}
var newend []byte
if end == nil {
newend = cpIncr(s.prefix)
} else {
newend = append(clone(s.prefix), end...)
}
iter := s.parent.ReverseIterator(newstart, newend)
if start == nil {
skipOne(iter, cpIncr(s.prefix))
}
return prefixIterator{
prefix: s.prefix,
iter: s.parent.ReverseIterator(start, end),
start: newstart,
end: newend,
iter: iter,
}
}
type prefixIterator struct {
prefix []byte
iter Iterator
prefix []byte
start, end []byte
iter Iterator
valid bool
}
// Implements Iterator
func (iter prefixIterator) Domain() (start []byte, end []byte) {
start, end = iter.iter.Domain()
start = start[len(iter.prefix):]
end = end[len(iter.prefix):]
return
func (iter prefixIterator) Domain() ([]byte, []byte) {
return iter.start, iter.end
}
// Implements Iterator
func (iter prefixIterator) Valid() bool {
return iter.iter.Valid()
return iter.valid && iter.iter.Valid()
}
// Implements Iterator
func (iter prefixIterator) Next() {
if !iter.valid {
panic("prefixIterator invalid, cannot call Next()")
}
iter.iter.Next()
if !iter.iter.Valid() || !bytes.HasPrefix(iter.iter.Key(), iter.prefix) {
iter.iter.Close()
iter.valid = false
}
}
// Implements Iterator
@ -124,3 +168,43 @@ func (iter prefixIterator) Value() []byte {
func (iter prefixIterator) Close() {
iter.iter.Close()
}
// copied from github.com/tendermint/tendermint/libs/db/prefix_db.go
func stripPrefix(key []byte, prefix []byte) []byte {
if len(key) < len(prefix) || !bytes.Equal(key[:len(prefix)], prefix) {
panic("should not happen")
}
return key[len(prefix):]
}
// wrapping sdk.PrefixEndBytes
func cpIncr(bz []byte) []byte {
return sdk.PrefixEndBytes(bz)
}
// copied from github.com/tendermint/tendermint/libs/db/util.go
func cpDecr(bz []byte) (ret []byte) {
if len(bz) == 0 {
panic("cpDecr expects non-zero bz length")
}
ret = clone(bz)
for i := len(bz) - 1; i >= 0; i-- {
if ret[i] > byte(0x00) {
ret[i]--
return
}
ret[i] = byte(0xFF)
if i == 0 {
return nil
}
}
return nil
}
func skipOne(iter Iterator, skipKey []byte) {
if iter.Valid() {
if bytes.Equal(iter.Key(), skipKey) {
iter.Next()
}
}
}

View File

@ -1,6 +1,7 @@
package store
import (
"bytes"
"math/rand"
"testing"
@ -105,7 +106,75 @@ func TestPrefixStoreIterate(t *testing.T) {
pIter.Next()
}
require.Equal(t, bIter.Valid(), pIter.Valid())
bIter.Close()
pIter.Close()
}
func TestPrefixStoreIteratorEdgeCase(t *testing.T) {
db := dbm.NewMemDB()
baseStore := dbStoreAdapter{db}
// overflow in cpIncr
prefix := []byte{0xAA, 0xFF, 0xFF}
prefixStore := baseStore.Prefix(prefix)
// ascending order
baseStore.Set([]byte{0xAA, 0xFF, 0xFE}, []byte{})
baseStore.Set([]byte{0xAA, 0xFF, 0xFE, 0x00}, []byte{})
baseStore.Set([]byte{0xAA, 0xFF, 0xFF}, []byte{})
baseStore.Set([]byte{0xAA, 0xFF, 0xFF, 0x00}, []byte{})
baseStore.Set([]byte{0xAB}, []byte{})
baseStore.Set([]byte{0xAB, 0x00}, []byte{})
baseStore.Set([]byte{0xAB, 0x00, 0x00}, []byte{})
for iter := prefixStore.Iterator(nil, nil); iter.Valid(); iter.Next() {
require.True(t, bytes.HasPrefix(iter.Key(), prefix))
}
}
func TestPrefixStoreReverseIteratorEdgeCase(t *testing.T) {
db := dbm.NewMemDB()
baseStore := dbStoreAdapter{db}
// overflow in cpIncr
prefix := []byte{0xAA, 0xFF, 0xFF}
prefixStore := baseStore.Prefix(prefix)
// descending order
baseStore.Set([]byte{0xAB, 0x00, 0x00}, []byte{})
baseStore.Set([]byte{0xAB, 0x00}, []byte{})
baseStore.Set([]byte{0xAB}, []byte{})
baseStore.Set([]byte{0xAA, 0xFF, 0xFF, 0x00}, []byte{})
baseStore.Set([]byte{0xAA, 0xFF, 0xFF}, []byte{})
baseStore.Set([]byte{0xAA, 0xFF, 0xFE, 0x00}, []byte{})
baseStore.Set([]byte{0xAA, 0xFF, 0xFE}, []byte{})
iter := prefixStore.ReverseIterator(nil, nil)
for ; iter.Valid(); iter.Next() {
require.True(t, bytes.HasPrefix(iter.Key(), prefix))
}
iter.Close()
db = dbm.NewMemDB()
baseStore = dbStoreAdapter{db}
// underflow in cpDecr
prefix = []byte{0xAA, 0x00, 0x00}
prefixStore = baseStore.Prefix(prefix)
baseStore.Set([]byte{0xAB, 0x00, 0x01, 0x00, 0x00}, []byte{})
baseStore.Set([]byte{0xAB, 0x00, 0x01, 0x00}, []byte{})
baseStore.Set([]byte{0xAB, 0x00, 0x01}, []byte{})
baseStore.Set([]byte{0xAA, 0x00, 0x00, 0x00}, []byte{})
baseStore.Set([]byte{0xAA, 0x00, 0x00}, []byte{})
baseStore.Set([]byte{0xA9, 0xFF, 0xFF, 0x00}, []byte{})
baseStore.Set([]byte{0xA9, 0xFF, 0xFF}, []byte{})
iter = prefixStore.ReverseIterator(nil, nil)
for ; iter.Valid(); iter.Next() {
require.True(t, bytes.HasPrefix(iter.Key(), prefix))
}
iter.Close()
}