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package kv
import (
"bytes"
"encoding/hex"
"fmt"
"sort"
"strconv"
"strings"
"time"
"github.com/pkg/errors"
cmn "github.com/tendermint/tendermint/libs/common"
dbm "github.com/tendermint/tendermint/libs/db"
"github.com/tendermint/tendermint/libs/pubsub/query"
"github.com/tendermint/tendermint/state/txindex"
"github.com/tendermint/tendermint/types"
)
const (
tagKeySeparator = "/"
)
var _ txindex.TxIndexer = (*TxIndex)(nil)
// TxIndex is the simplest possible indexer, backed by key-value storage (levelDB).
type TxIndex struct {
store dbm.DB
tagsToIndex []string
indexAllTags bool
}
// NewTxIndex creates new KV indexer.
func NewTxIndex(store dbm.DB, options ...func(*TxIndex)) *TxIndex {
txi := &TxIndex{store: store, tagsToIndex: make([]string, 0), indexAllTags: false}
for _, o := range options {
o(txi)
}
return txi
}
// IndexTags is an option for setting which tags to index.
func IndexTags(tags []string) func(*TxIndex) {
return func(txi *TxIndex) {
txi.tagsToIndex = tags
}
}
// IndexAllTags is an option for indexing all tags.
func IndexAllTags() func(*TxIndex) {
return func(txi *TxIndex) {
txi.indexAllTags = true
}
}
// Get gets transaction from the TxIndex storage and returns it or nil if the
// transaction is not found.
func (txi *TxIndex) Get(hash []byte) (*types.TxResult, error) {
if len(hash) == 0 {
return nil, txindex.ErrorEmptyHash
}
rawBytes := txi.store.Get(hash)
if rawBytes == nil {
return nil, nil
}
txResult := new(types.TxResult)
err := cdc.UnmarshalBinaryBare(rawBytes, &txResult)
if err != nil {
return nil, fmt.Errorf("Error reading TxResult: %v", err)
}
return txResult, nil
}
// AddBatch indexes a batch of transactions using the given list of tags.
func (txi *TxIndex) AddBatch(b *txindex.Batch) error {
storeBatch := txi.store.NewBatch()
for _, result := range b.Ops {
hash := result.Tx.Hash()
// index tx by tags
for _, tag := range result.Result.Tags {
if txi.indexAllTags || cmn.StringInSlice(string(tag.Key), txi.tagsToIndex) {
storeBatch.Set(keyForTag(tag, result), hash)
}
}
// index tx by hash
rawBytes, err := cdc.MarshalBinaryBare(result)
if err != nil {
return err
}
storeBatch.Set(hash, rawBytes)
}
storeBatch.Write()
return nil
}
// Index indexes a single transaction using the given list of tags.
func (txi *TxIndex) Index(result *types.TxResult) error {
b := txi.store.NewBatch()
hash := result.Tx.Hash()
// index tx by tags
for _, tag := range result.Result.Tags {
if txi.indexAllTags || cmn.StringInSlice(string(tag.Key), txi.tagsToIndex) {
b.Set(keyForTag(tag, result), hash)
}
}
// index tx by hash
rawBytes, err := cdc.MarshalBinaryBare(result)
if err != nil {
return err
}
b.Set(hash, rawBytes)
b.Write()
return nil
}
// Search performs a search using the given query. It breaks the query into
// conditions (like "tx.height > 5"). For each condition, it queries the DB
// index. One special use cases here: (1) if "tx.hash" is found, it returns tx
// result for it (2) for range queries it is better for the client to provide
// both lower and upper bounds, so we are not performing a full scan. Results
// from querying indexes are then intersected and returned to the caller.
func (txi *TxIndex) Search(q *query.Query) ([]*types.TxResult, error) {
var hashes [][]byte
var hashesInitialized bool
// get a list of conditions (like "tx.height > 5")
conditions := q.Conditions()
// if there is a hash condition, return the result immediately
hash, err, ok := lookForHash(conditions)
if err != nil {
return nil, errors.Wrap(err, "error during searching for a hash in the query")
} else if ok {
res, err := txi.Get(hash)
if res == nil {
return []*types.TxResult{}, nil
}
return []*types.TxResult{res}, errors.Wrap(err, "error while retrieving the result")
}
// conditions to skip because they're handled before "everything else"
skipIndexes := make([]int, 0)
// if there is a height condition ("tx.height=3"), extract it for faster lookups
height, heightIndex := lookForHeight(conditions)
if heightIndex >= 0 {
skipIndexes = append(skipIndexes, heightIndex)
}
// extract ranges
// if both upper and lower bounds exist, it's better to get them in order not
// no iterate over kvs that are not within range.
ranges, rangeIndexes := lookForRanges(conditions)
if len(ranges) > 0 {
skipIndexes = append(skipIndexes, rangeIndexes...)
for _, r := range ranges {
if !hashesInitialized {
hashes = txi.matchRange(r, []byte(r.key))
hashesInitialized = true
} else {
hashes = intersect(hashes, txi.matchRange(r, []byte(r.key)))
}
}
}
// for all other conditions
for i, c := range conditions {
if cmn.IntInSlice(i, skipIndexes) {
continue
}
if !hashesInitialized {
hashes = txi.match(c, startKey(c, height))
hashesInitialized = true
} else {
hashes = intersect(hashes, txi.match(c, startKey(c, height)))
}
}
results := make([]*types.TxResult, len(hashes))
i := 0
for _, h := range hashes {
results[i], err = txi.Get(h)
if err != nil {
return nil, errors.Wrapf(err, "failed to get Tx{%X}", h)
}
i++
}
// sort by height by default
sort.Slice(results, func(i, j int) bool {
return results[i].Height < results[j].Height
})
return results, nil
}
func lookForHash(conditions []query.Condition) (hash []byte, err error, ok bool) {
for _, c := range conditions {
if c.Tag == types.TxHashKey {
decoded, err := hex.DecodeString(c.Operand.(string))
return decoded, err, true
}
}
return
}
func lookForHeight(conditions []query.Condition) (height int64, index int) {
for i, c := range conditions {
if c.Tag == types.TxHeightKey {
return c.Operand.(int64), i
}
}
return 0, -1
}
// special map to hold range conditions
// Example: account.number => queryRange{lowerBound: 1, upperBound: 5}
type queryRanges map[string]queryRange
type queryRange struct {
key string
lowerBound interface{} // int || time.Time
includeLowerBound bool
upperBound interface{} // int || time.Time
includeUpperBound bool
}
func (r queryRange) lowerBoundValue() interface{} {
if r.lowerBound == nil {
return nil
}
if r.includeLowerBound {
return r.lowerBound
} else {
switch t := r.lowerBound.(type) {
case int64:
return t + 1
case time.Time:
return t.Unix() + 1
default:
panic("not implemented")
}
}
}
func (r queryRange) AnyBound() interface{} {
if r.lowerBound != nil {
return r.lowerBound
} else {
return r.upperBound
}
}
func (r queryRange) upperBoundValue() interface{} {
if r.upperBound == nil {
return nil
}
if r.includeUpperBound {
return r.upperBound
} else {
switch t := r.upperBound.(type) {
case int64:
return t - 1
case time.Time:
return t.Unix() - 1
default:
panic("not implemented")
}
}
}
func lookForRanges(conditions []query.Condition) (ranges queryRanges, indexes []int) {
ranges = make(queryRanges)
for i, c := range conditions {
if isRangeOperation(c.Op) {
r, ok := ranges[c.Tag]
if !ok {
r = queryRange{key: c.Tag}
}
switch c.Op {
case query.OpGreater:
r.lowerBound = c.Operand
case query.OpGreaterEqual:
r.includeLowerBound = true
r.lowerBound = c.Operand
case query.OpLess:
r.upperBound = c.Operand
case query.OpLessEqual:
r.includeUpperBound = true
r.upperBound = c.Operand
}
ranges[c.Tag] = r
indexes = append(indexes, i)
}
}
return ranges, indexes
}
func isRangeOperation(op query.Operator) bool {
switch op {
case query.OpGreater, query.OpGreaterEqual, query.OpLess, query.OpLessEqual:
return true
default:
return false
}
}
func (txi *TxIndex) match(c query.Condition, startKey []byte) (hashes [][]byte) {
if c.Op == query.OpEqual {
it := dbm.IteratePrefix(txi.store, startKey)
defer it.Close()
for ; it.Valid(); it.Next() {
hashes = append(hashes, it.Value())
}
} else if c.Op == query.OpContains {
// XXX: doing full scan because startKey does not apply here
// For example, if startKey = "account.owner=an" and search query = "accoutn.owner CONSISTS an"
// we can't iterate with prefix "account.owner=an" because we might miss keys like "account.owner=Ulan"
it := txi.store.Iterator(nil, nil)
defer it.Close()
for ; it.Valid(); it.Next() {
if !isTagKey(it.Key()) {
continue
}
if strings.Contains(extractValueFromKey(it.Key()), c.Operand.(string)) {
hashes = append(hashes, it.Value())
}
}
} else {
panic("other operators should be handled already")
}
return
}
func (txi *TxIndex) matchRange(r queryRange, prefix []byte) (hashes [][]byte) {
// create a map to prevent duplicates
hashesMap := make(map[string][]byte)
lowerBound := r.lowerBoundValue()
upperBound := r.upperBoundValue()
it := dbm.IteratePrefix(txi.store, prefix)
defer it.Close()
LOOP:
for ; it.Valid(); it.Next() {
if !isTagKey(it.Key()) {
continue
}
switch r.AnyBound().(type) {
case int64:
v, err := strconv.ParseInt(extractValueFromKey(it.Key()), 10, 64)
if err != nil {
continue LOOP
}
include := true
if lowerBound != nil && v < lowerBound.(int64) {
include = false
}
if upperBound != nil && v > upperBound.(int64) {
include = false
}
if include {
hashesMap[fmt.Sprintf("%X", it.Value())] = it.Value()
}
// XXX: passing time in a ABCI Tags is not yet implemented
// case time.Time:
// v := strconv.ParseInt(extractValueFromKey(it.Key()), 10, 64)
// if v == r.upperBound {
// break
// }
}
}
hashes = make([][]byte, len(hashesMap))
i := 0
for _, h := range hashesMap {
hashes[i] = h
i++
}
return
}
///////////////////////////////////////////////////////////////////////////////
// Keys
func startKey(c query.Condition, height int64) []byte {
var key string
if height > 0 {
key = fmt.Sprintf("%s/%v/%d", c.Tag, c.Operand, height)
} else {
key = fmt.Sprintf("%s/%v", c.Tag, c.Operand)
}
return []byte(key)
}
func isTagKey(key []byte) bool {
return strings.Count(string(key), tagKeySeparator) == 3
}
func extractValueFromKey(key []byte) string {
parts := strings.SplitN(string(key), tagKeySeparator, 3)
return parts[1]
}
func keyForTag(tag cmn.KVPair, result *types.TxResult) []byte {
return []byte(fmt.Sprintf("%s/%s/%d/%d", tag.Key, tag.Value, result.Height, result.Index))
}
///////////////////////////////////////////////////////////////////////////////
// Utils
func intersect(as, bs [][]byte) [][]byte {
i := make([][]byte, 0, cmn.MinInt(len(as), len(bs)))
for _, a := range as {
for _, b := range bs {
if bytes.Equal(a, b) {
i = append(i, a)
}
}
}
return i
}