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package kv
import (
"context"
"errors"
"fmt"
"sort"
"strconv"
"strings"
"github.com/google/orderedcode"
dbm "github.com/tendermint/tm-db"
abci "github.com/tendermint/tendermint/abci/types"
"github.com/tendermint/tendermint/internal/pubsub/query"
"github.com/tendermint/tendermint/internal/pubsub/query/syntax"
"github.com/tendermint/tendermint/internal/state/indexer"
"github.com/tendermint/tendermint/types"
)
var _ indexer.BlockIndexer = (*BlockerIndexer)(nil)
// BlockerIndexer implements a block indexer, indexing BeginBlock and EndBlock
// events with an underlying KV store. Block events are indexed by their height,
// such that matching search criteria returns the respective block height(s).
type BlockerIndexer struct {
store dbm.DB
}
func New(store dbm.DB) *BlockerIndexer {
return &BlockerIndexer{
store: store,
}
}
// Has returns true if the given height has been indexed. An error is returned
// upon database query failure.
func (idx *BlockerIndexer) Has(height int64) (bool, error) {
key, err := heightKey(height)
if err != nil {
return false, fmt.Errorf("failed to create block height index key: %w", err)
}
return idx.store.Has(key)
}
// Index indexes BeginBlock and EndBlock events for a given block by its height.
// The following is indexed:
//
// primary key: encode(block.height | height) => encode(height)
// BeginBlock events: encode(eventType.eventAttr|eventValue|height|begin_block) => encode(height)
// EndBlock events: encode(eventType.eventAttr|eventValue|height|end_block) => encode(height)
func (idx *BlockerIndexer) Index(bh types.EventDataNewBlockHeader) error {
batch := idx.store.NewBatch()
defer batch.Close()
height := bh.Header.Height
// 1. index by height
key, err := heightKey(height)
if err != nil {
return fmt.Errorf("failed to create block height index key: %w", err)
}
if err := batch.Set(key, int64ToBytes(height)); err != nil {
return err
}
// 2. index BeginBlock events
if err := idx.indexEvents(batch, bh.ResultBeginBlock.Events, "begin_block", height); err != nil {
return fmt.Errorf("failed to index BeginBlock events: %w", err)
}
// 3. index EndBlock events
if err := idx.indexEvents(batch, bh.ResultEndBlock.Events, "end_block", height); err != nil {
return fmt.Errorf("failed to index EndBlock events: %w", err)
}
return batch.WriteSync()
}
// Search performs a query for block heights that match a given BeginBlock
// and Endblock event search criteria. The given query can match against zero,
// one or more block heights. In the case of height queries, i.e. block.height=H,
// if the height is indexed, that height alone will be returned. An error and
// nil slice is returned. Otherwise, a non-nil slice and nil error is returned.
func (idx *BlockerIndexer) Search(ctx context.Context, q *query.Query) ([]int64, error) {
results := make([]int64, 0)
select {
case <-ctx.Done():
return results, nil
default:
}
conditions := q.Syntax()
// If there is an exact height query, return the result immediately
// (if it exists).
height, ok := lookForHeight(conditions)
if ok {
ok, err := idx.Has(height)
if err != nil {
return nil, err
}
if ok {
return []int64{height}, nil
}
return results, nil
}
var heightsInitialized bool
filteredHeights := make(map[string][]byte)
// conditions to skip because they're handled before "everything else"
skipIndexes := make([]int, 0)
// Extract ranges. If both upper and lower bounds exist, it's better to get
// them in order as to not iterate over kvs that are not within range.
ranges, rangeIndexes := indexer.LookForRanges(conditions)
if len(ranges) > 0 {
skipIndexes = append(skipIndexes, rangeIndexes...)
for _, qr := range ranges {
prefix, err := orderedcode.Append(nil, qr.Key)
if err != nil {
return nil, fmt.Errorf("failed to create prefix key: %w", err)
}
if !heightsInitialized {
filteredHeights, err = idx.matchRange(ctx, qr, prefix, filteredHeights, true)
if err != nil {
return nil, err
}
heightsInitialized = true
// Ignore any remaining conditions if the first condition resulted in no
// matches (assuming implicit AND operand).
if len(filteredHeights) == 0 {
break
}
} else {
filteredHeights, err = idx.matchRange(ctx, qr, prefix, filteredHeights, false)
if err != nil {
return nil, err
}
}
}
}
// for all other conditions
for i, c := range conditions {
if intInSlice(i, skipIndexes) {
continue
}
startKey, err := orderedcode.Append(nil, c.Tag, c.Arg.Value())
if err != nil {
return nil, err
}
if !heightsInitialized {
filteredHeights, err = idx.match(ctx, c, startKey, filteredHeights, true)
if err != nil {
return nil, err
}
heightsInitialized = true
// Ignore any remaining conditions if the first condition resulted in no
// matches (assuming implicit AND operand).
if len(filteredHeights) == 0 {
break
}
} else {
filteredHeights, err = idx.match(ctx, c, startKey, filteredHeights, false)
if err != nil {
return nil, err
}
}
}
// fetch matching heights
results = make([]int64, 0, len(filteredHeights))
heights:
for _, hBz := range filteredHeights {
h := int64FromBytes(hBz)
ok, err := idx.Has(h)
if err != nil {
return nil, err
}
if ok {
results = append(results, h)
}
select {
case <-ctx.Done():
break heights
default:
}
}
sort.Slice(results, func(i, j int) bool { return results[i] < results[j] })
return results, nil
}
// matchRange returns all matching block heights that match a given QueryRange
// and start key. An already filtered result (filteredHeights) is provided such
// that any non-intersecting matches are removed.
//
// NOTE: The provided filteredHeights may be empty if no previous condition has
// matched.
func (idx *BlockerIndexer) matchRange(
ctx context.Context,
qr indexer.QueryRange,
startKey []byte,
filteredHeights map[string][]byte,
firstRun bool,
) (map[string][]byte, error) {
// A previous match was attempted but resulted in no matches, so we return
// no matches (assuming AND operand).
if !firstRun && len(filteredHeights) == 0 {
return filteredHeights, nil
}
tmpHeights := make(map[string][]byte)
lowerBound := qr.LowerBoundValue()
upperBound := qr.UpperBoundValue()
it, err := dbm.IteratePrefix(idx.store, startKey)
if err != nil {
return nil, fmt.Errorf("failed to create prefix iterator: %w", err)
}
defer it.Close()
iter:
for ; it.Valid(); it.Next() {
var (
eventValue string
err error
)
if qr.Key == types.BlockHeightKey {
eventValue, err = parseValueFromPrimaryKey(it.Key())
} else {
eventValue, err = parseValueFromEventKey(it.Key())
}
if err != nil {
continue
}
if _, ok := qr.AnyBound().(int64); ok {
v, err := strconv.ParseInt(eventValue, 10, 64)
if err != nil {
continue iter
}
include := true
if lowerBound != nil && v < lowerBound.(int64) {
include = false
}
if upperBound != nil && v > upperBound.(int64) {
include = false
}
if include {
tmpHeights[string(it.Value())] = it.Value()
}
}
select {
case <-ctx.Done():
break iter
default:
}
}
if err := it.Error(); err != nil {
return nil, err
}
if len(tmpHeights) == 0 || firstRun {
// Either:
//
// 1. Regardless if a previous match was attempted, which may have had
// results, but no match was found for the current condition, then we
// return no matches (assuming AND operand).
//
// 2. A previous match was not attempted, so we return all results.
return tmpHeights, nil
}
// Remove/reduce matches in filteredHashes that were not found in this
// match (tmpHashes).
for k := range filteredHeights {
if tmpHeights[k] == nil {
delete(filteredHeights, k)
select {
case <-ctx.Done():
break
default:
}
}
}
return filteredHeights, nil
}
// match returns all matching heights that meet a given query condition and start
// key. An already filtered result (filteredHeights) is provided such that any
// non-intersecting matches are removed.
//
// NOTE: The provided filteredHeights may be empty if no previous condition has
// matched.
func (idx *BlockerIndexer) match(
ctx context.Context,
c syntax.Condition,
startKeyBz []byte,
filteredHeights map[string][]byte,
firstRun bool,
) (map[string][]byte, error) {
// A previous match was attempted but resulted in no matches, so we return
// no matches (assuming AND operand).
if !firstRun && len(filteredHeights) == 0 {
return filteredHeights, nil
}
tmpHeights := make(map[string][]byte)
switch {
case c.Op == syntax.TEq:
it, err := dbm.IteratePrefix(idx.store, startKeyBz)
if err != nil {
return nil, fmt.Errorf("failed to create prefix iterator: %w", err)
}
defer it.Close()
for ; it.Valid(); it.Next() {
tmpHeights[string(it.Value())] = it.Value()
if err := ctx.Err(); err != nil {
break
}
}
if err := it.Error(); err != nil {
return nil, err
}
case c.Op == syntax.TExists:
prefix, err := orderedcode.Append(nil, c.Tag)
if err != nil {
return nil, err
}
it, err := dbm.IteratePrefix(idx.store, prefix)
if err != nil {
return nil, fmt.Errorf("failed to create prefix iterator: %w", err)
}
defer it.Close()
iterExists:
for ; it.Valid(); it.Next() {
tmpHeights[string(it.Value())] = it.Value()
select {
case <-ctx.Done():
break iterExists
default:
}
}
if err := it.Error(); err != nil {
return nil, err
}
case c.Op == syntax.TContains:
prefix, err := orderedcode.Append(nil, c.Tag)
if err != nil {
return nil, err
}
it, err := dbm.IteratePrefix(idx.store, prefix)
if err != nil {
return nil, fmt.Errorf("failed to create prefix iterator: %w", err)
}
defer it.Close()
iterContains:
for ; it.Valid(); it.Next() {
eventValue, err := parseValueFromEventKey(it.Key())
if err != nil {
continue
}
if strings.Contains(eventValue, c.Arg.Value()) {
tmpHeights[string(it.Value())] = it.Value()
}
select {
case <-ctx.Done():
break iterContains
default:
}
}
if err := it.Error(); err != nil {
return nil, err
}
default:
return nil, errors.New("other operators should be handled already")
}
if len(tmpHeights) == 0 || firstRun {
// Either:
//
// 1. Regardless if a previous match was attempted, which may have had
// results, but no match was found for the current condition, then we
// return no matches (assuming AND operand).
//
// 2. A previous match was not attempted, so we return all results.
return tmpHeights, nil
}
// Remove/reduce matches in filteredHeights that were not found in this
// match (tmpHeights).
for k := range filteredHeights {
if tmpHeights[k] == nil {
delete(filteredHeights, k)
select {
case <-ctx.Done():
break
default:
}
}
}
return filteredHeights, nil
}
func (idx *BlockerIndexer) indexEvents(batch dbm.Batch, events []abci.Event, typ string, height int64) error {
heightBz := int64ToBytes(height)
for _, event := range events {
// only index events with a non-empty type
if len(event.Type) == 0 {
continue
}
for _, attr := range event.Attributes {
if len(attr.Key) == 0 {
continue
}
// index iff the event specified index:true and it's not a reserved event
compositeKey := fmt.Sprintf("%s.%s", event.Type, attr.Key)
if compositeKey == types.BlockHeightKey {
return fmt.Errorf("event type and attribute key \"%s\" is reserved; please use a different key", compositeKey)
}
if attr.GetIndex() {
key, err := eventKey(compositeKey, typ, attr.Value, height)
if err != nil {
return fmt.Errorf("failed to create block index key: %w", err)
}
if err := batch.Set(key, heightBz); err != nil {
return err
}
}
}
}
return nil
}