[#948] engine: Define cursor for object listing as a type

Signed-off-by: Alex Vanin <alexey@nspcc.ru>

pkg/local_object_storage/engine/list.go

@@ -1,19 +1,23 @@
 package engine
 
 import (
-	"fmt"
 	"sort"
-	"strconv"
 
 	"github.com/nspcc-dev/neofs-api-go/pkg/object"
 	core "github.com/nspcc-dev/neofs-node/pkg/core/object"
 	"github.com/nspcc-dev/neofs-node/pkg/local_object_storage/shard"
 )
 
+// Cursor is a type for continuous object listing.
+type Cursor struct {
+	shardID     string
+	shardCursor *shard.Cursor
+}
+
 // ListWithCursorPrm contains parameters for ListWithCursor operation.
 type ListWithCursorPrm struct {
 	count  uint32
-	cursor string
+	cursor *Cursor
 }
 
 // WithCount sets maximum amount of addresses that ListWithCursor can return.
@@ -23,9 +27,9 @@ func (p *ListWithCursorPrm) WithCount(count uint32) *ListWithCursorPrm {
 }
 
 // WithCursor sets cursor for ListWithCursor operation. For initial request
-// ignore this param or use empty string. For continues requests, use  value
+// ignore this param or use nil value. For continues requests, use  value
 // from ListWithCursorRes.
-func (p *ListWithCursorPrm) WithCursor(cursor string) *ListWithCursorPrm {
+func (p *ListWithCursorPrm) WithCursor(cursor *Cursor) *ListWithCursorPrm {
 	p.cursor = cursor
 	return p
 }
@@ -33,7 +37,7 @@ func (p *ListWithCursorPrm) WithCursor(cursor string) *ListWithCursorPrm {
 // ListWithCursorRes contains values returned from ListWithCursor operation.
 type ListWithCursorRes struct {
 	addrList []*object.Address
-	cursor   string
+	cursor   *Cursor
 }
 
 // AddressList returns addresses selected by ListWithCursor operation.
@@ -42,7 +46,7 @@ func (l ListWithCursorRes) AddressList() []*object.Address {
 }
 
 // Cursor returns cursor for consecutive listing requests.
-func (l ListWithCursorRes) Cursor() string {
+func (l ListWithCursorRes) Cursor() *Cursor {
 	return l.cursor
 }
 
@@ -51,10 +55,7 @@ func (l ListWithCursorRes) Cursor() string {
 // Does not include inhumed objects. Use cursor value from response
 // for consecutive requests.
 func (e *StorageEngine) ListWithCursor(prm *ListWithCursorPrm) (*ListWithCursorRes, error) {
-	var (
+	result := make([]*object.Address, 0, prm.count)
-		err    error
-		result = make([]*object.Address, 0, prm.count)
-	)
 
 	// 1. Get available shards and sort them.
 	e.mtx.RLock()
@@ -72,14 +73,10 @@ func (e *StorageEngine) ListWithCursor(prm *ListWithCursorPrm) (*ListWithCursorR
 		return shardIDs[i] < shardIDs[j]
 	})
 
-	// 2. Decode shard ID from cursor.
+	// 2. Prepare cursor object.
 	cursor := prm.cursor
-	cursorShardID := shardIDs[0]
+	if cursor == nil {
-	if len(cursor) > 0 {
+		cursor = &Cursor{shardID: shardIDs[0]}
-		cursorShardID, cursor, err = decodeID(cursor)
-		if err != nil {
-			return nil, err
-		}
 	}
 
 	// 3. Iterate over available shards. Skip unavailable shards.
@@ -88,7 +85,7 @@ func (e *StorageEngine) ListWithCursor(prm *ListWithCursorPrm) (*ListWithCursorR
 			break
 		}
 
-		if shardIDs[i] < cursorShardID {
+		if shardIDs[i] < cursor.shardID {
 			continue
 		}
 
@@ -101,8 +98,8 @@ func (e *StorageEngine) ListWithCursor(prm *ListWithCursorPrm) (*ListWithCursorR
 
 		count := uint32(int(prm.count) - len(result))
 		shardPrm := new(shard.ListWithCursorPrm).WithCount(count)
-		if shardIDs[i] == cursorShardID {
+		if shardIDs[i] == cursor.shardID {
-			shardPrm.WithCursor(cursor)
+			shardPrm.WithCursor(cursor.shardCursor)
 		}
 
 		res, err := shardInstance.ListWithCursor(shardPrm)
@@ -111,8 +108,8 @@ func (e *StorageEngine) ListWithCursor(prm *ListWithCursorPrm) (*ListWithCursorR
 		}
 
 		result = append(result, res.AddressList()...)
-		cursor = res.Cursor()
+		cursor.shardCursor = res.Cursor()
-		cursorShardID = shardIDs[i]
+		cursor.shardID = shardIDs[i]
 	}
 
 	if len(result) == 0 {
@@ -121,29 +118,6 @@ func (e *StorageEngine) ListWithCursor(prm *ListWithCursorPrm) (*ListWithCursorR
 
 	return &ListWithCursorRes{
 		addrList: result,
-		cursor:   encodeID(cursorShardID, cursor),
+		cursor:   cursor,
 	}, nil
 }
-
-func decodeID(cursor string) (shardID string, shardCursor string, err error) {
-	ln := len(cursor)
-	if ln < 2 {
-		return "", "", fmt.Errorf("invalid cursor %s", cursor)
-	}
-
-	idLen, err := strconv.Atoi(cursor[:2])
-	if err != nil {
-		return "", "", fmt.Errorf("invalid cursor %s", cursor)
-	}
-
-	if len(cursor) < 2+idLen {
-		return "", "", fmt.Errorf("invalid cursor %s", cursor)
-	}
-
-	return cursor[2 : 2+idLen], cursor[2+idLen:], nil
-}
-
-func encodeID(id, cursor string) string {
-	prefix := fmt.Sprintf("%02d", len(id))
-	return prefix + id + cursor
-}

pkg/local_object_storage/metabase/list.go

@@ -1,18 +1,21 @@
 package meta
 
 import (
-	"fmt"
-	"strings"
-
 	"github.com/nspcc-dev/neofs-api-go/pkg/object"
 	core "github.com/nspcc-dev/neofs-node/pkg/core/object"
 	"go.etcd.io/bbolt"
 )
 
+// Cursor is a type for continuous object listing.
+type Cursor struct {
+	bucket  uint8
+	address *object.Address
+}
+
 // ListPrm contains parameters for ListWithCursor operation.
 type ListPrm struct {
 	count  int
-	cursor string
+	cursor *Cursor
 }
 
 // WithCount sets maximum amount of addresses that ListWithCursor can return.
@@ -22,9 +25,9 @@ func (l *ListPrm) WithCount(count uint32) *ListPrm {
 }
 
 // WithCursor sets cursor for ListWithCursor operation. For initial request
-// ignore this param or use empty string. For continues requests, use value
+// ignore this param or use nil value. For continues requests, use value
 // from ListRes.
-func (l *ListPrm) WithCursor(cursor string) *ListPrm {
+func (l *ListPrm) WithCursor(cursor *Cursor) *ListPrm {
 	l.cursor = cursor
 	return l
 }
@@ -32,7 +35,7 @@ func (l *ListPrm) WithCursor(cursor string) *ListPrm {
 // ListRes contains values returned from ListWithCursor operation.
 type ListRes struct {
 	addrList []*object.Address
-	cursor   string
+	cursor   *Cursor
 }
 
 // AddressList returns addresses selected by ListWithCursor operation.
@@ -41,23 +44,23 @@ func (l ListRes) AddressList() []*object.Address {
 }
 
 // Cursor returns cursor for consecutive listing requests.
-func (l ListRes) Cursor() string {
+func (l ListRes) Cursor() *Cursor {
 	return l.cursor
 }
 
 const (
-	cursorPrefixPrimary   = 'p'
+	cursorBucketPrimary = iota
-	cursorPrefixTombstone = 't'
+	cursorBucketTombstone
-	cursorPrefixSG        = 's'
+	cursorBucketSG
 )
 
 // ListWithCursor lists physical objects available in metabase. Includes regular,
 // tombstone and storage group objects. Does not include inhumed objects. Use
 // cursor value from response for consecutive requests.
-func ListWithCursor(db *DB, count uint32, cursor string) ([]*object.Address, string, error) {
+func ListWithCursor(db *DB, count uint32, cursor *Cursor) ([]*object.Address, *Cursor, error) {
 	r, err := db.ListWithCursor(new(ListPrm).WithCount(count).WithCursor(cursor))
 	if err != nil {
-		return nil, "", err
+		return nil, nil, err
 	}
 
 	return r.AddressList(), r.Cursor(), nil
@@ -76,25 +79,8 @@ func (db *DB) ListWithCursor(prm *ListPrm) (res *ListRes, err error) {
 	return res, err
 }
 
-func (db *DB) listWithCursor(tx *bbolt.Tx, count int, cursor string) ([]*object.Address, string, error) {
+func (db *DB) listWithCursor(tx *bbolt.Tx, count int, cursor *Cursor) ([]*object.Address, *Cursor, error) {
-	threshold := len(cursor) == 0 // threshold is a flag to ignore cursor
+	threshold := cursor == nil // threshold is a flag to ignore cursor
-	a := object.NewAddress()
-	var cursorPrefix uint8
-
-	if !threshold { // if cursor is present, then decode it and check sanity
-		cursorPrefix = cursor[0]
-		switch cursorPrefix {
-		case cursorPrefixPrimary, cursorPrefixSG, cursorPrefixTombstone:
-		default:
-			return nil, "", fmt.Errorf("invalid cursor prefix %s", string(cursorPrefix))
-		}
-
-		cursor = cursor[1:]
-		if err := a.Parse(cursor); err != nil {
-			return nil, "", fmt.Errorf("invalid cursor address: %w", err)
-		}
-	}
-
 	result := make([]*object.Address, 0, count)
 	unique := make(map[string]struct{}) // do not parse the same containerID twice
 
@@ -102,7 +88,7 @@ func (db *DB) listWithCursor(tx *bbolt.Tx, count int, cursor string) ([]*object.
 	name, _ := c.First()
 
 	if !threshold {
-		name, _ = c.Seek([]byte(a.ContainerID().String()))
+		name, _ = c.Seek([]byte(cursor.address.ContainerID().String()))
 	}
 
 loop:
@@ -117,20 +103,20 @@ loop:
 
 		lookupBuckets := [...]struct {
 			name   []byte
-			prefix uint8
+			bucket uint8
 		}{
-			{primaryBucketName(containerID), cursorPrefixPrimary},
+			{primaryBucketName(containerID), cursorBucketPrimary},
-			{tombstoneBucketName(containerID), cursorPrefixTombstone},
+			{tombstoneBucketName(containerID), cursorBucketTombstone},
-			{storageGroupBucketName(containerID), cursorPrefixSG},
+			{storageGroupBucketName(containerID), cursorBucketSG},
 		}
 
 		for _, lb := range lookupBuckets {
-			if !threshold && cursorPrefix != lb.prefix {
+			if !threshold && cursor.bucket != lb.bucket {
-				continue // start from the bucket, specified in the cursor prefix
+				continue // start from the bucket, specified in the cursor bucket
 			}
 
-			cursorPrefix = lb.prefix
 			result, cursor = selectNFromBucket(tx, lb.name, prefix, result, count, cursor, threshold)
+			cursor.bucket = lb.bucket
 			if len(result) >= count {
 				break loop
 			}
@@ -142,10 +128,10 @@ loop:
 	}
 
 	if len(result) == 0 {
-		return nil, "", core.ErrEndOfListing
+		return nil, nil, core.ErrEndOfListing
 	}
 
-	return result, string(cursorPrefix) + cursor, nil
+	return result, cursor, nil
 }
 
 // selectNFromBucket similar to selectAllFromBucket but uses cursor to find
@@ -155,22 +141,24 @@ func selectNFromBucket(tx *bbolt.Tx,
 	prefix string, // string of CID, optimization
 	to []*object.Address, // listing result
 	limit int, // stop listing at `limit` items in result
-	cursor string, // start from cursor object
+	cursor *Cursor, // start from cursor object
 	threshold bool, // ignore cursor and start immediately
-) ([]*object.Address, string) {
+) ([]*object.Address, *Cursor) {
 	bkt := tx.Bucket(name)
 	if bkt == nil {
 		return to, cursor
 	}
 
-	count := len(to)
+	if cursor == nil {
+		cursor = new(Cursor)
+	}
 
+	count := len(to)
 	c := bkt.Cursor()
 	k, _ := c.First()
 
 	if !threshold {
-		seekKey := strings.Replace(cursor, prefix, "", 1)
+		c.Seek([]byte(cursor.address.ObjectID().String()))
-		c.Seek([]byte(seekKey))
 		k, _ = c.Next() // we are looking for objects _after_ the cursor
 	}
 
@@ -178,19 +166,14 @@ func selectNFromBucket(tx *bbolt.Tx,
 		if count >= limit {
 			break
 		}
-
-		key := prefix + string(k)
-		cursor = key
-
 		a := object.NewAddress()
-		if err := a.Parse(key); err != nil {
+		if err := a.Parse(prefix + string(k)); err != nil {
 			break
 		}
-
+		cursor.address = a
 		if inGraveyard(tx, a) > 0 {
 			continue
 		}
-
 		to = append(to, a)
 		count++
 	}

pkg/local_object_storage/metabase/list_test.go

@@ -75,7 +75,7 @@ func TestLisObjectsWithCursor(t *testing.T) {
 		for countPerReq := 1; countPerReq <= total; countPerReq++ {
 			got := make([]*objectSDK.Address, 0, total)
 
-			res, cursor, err := meta.ListWithCursor(db, uint32(countPerReq), "")
+			res, cursor, err := meta.ListWithCursor(db, uint32(countPerReq), nil)
 			require.NoError(t, err, "count:%d", countPerReq)
 			got = append(got, res...)
 
@@ -98,19 +98,8 @@ func TestLisObjectsWithCursor(t *testing.T) {
 		}
 	})
 
-	t.Run("invalid cursor", func(t *testing.T) {
-		_, cursor, err := meta.ListWithCursor(db, total/2, "")
-		require.NoError(t, err)
-
-		_, _, err = meta.ListWithCursor(db, total/2, "x"+cursor[1:])
-		require.Error(t, err)
-
-		_, _, err = meta.ListWithCursor(db, total/2, cursor[1:])
-		require.Error(t, err)
-	})
-
 	t.Run("invalid count", func(t *testing.T) {
-		_, _, err := meta.ListWithCursor(db, 0, "")
+		_, _, err := meta.ListWithCursor(db, 0, nil)
 		require.ErrorIs(t, err, core.ErrEndOfListing)
 	})
 }
@@ -131,7 +120,7 @@ func TestAddObjectDuringListingWithCursor(t *testing.T) {
 	}
 
 	// get half of the objects
-	got, cursor, err := meta.ListWithCursor(db, total/2, "")
+	got, cursor, err := meta.ListWithCursor(db, total/2, nil)
 	require.NoError(t, err)
 	for _, obj := range got {
 		if _, ok := expected[obj.String()]; ok {

pkg/local_object_storage/shard/list.go

@@ -9,6 +9,9 @@ import (
 	"go.uber.org/zap"
 )
 
+// Cursor is a type for continuous object listing.
+type Cursor = meta.Cursor
+
 type ListContainersPrm struct{}
 
 type ListContainersRes struct {
@@ -22,13 +25,13 @@ func (r *ListContainersRes) Containers() []*cid.ID {
 // ListWithCursorPrm contains parameters for ListWithCursor operation.
 type ListWithCursorPrm struct {
 	count  uint32
-	cursor string
+	cursor *Cursor
 }
 
 // ListWithCursorRes contains values returned from ListWithCursor operation.
 type ListWithCursorRes struct {
 	addrList []*object.Address
-	cursor   string
+	cursor   *Cursor
 }
 
 // WithCount sets maximum amount of addresses that ListWithCursor can return.
@@ -38,9 +41,9 @@ func (p *ListWithCursorPrm) WithCount(count uint32) *ListWithCursorPrm {
 }
 
 // WithCursor sets cursor for ListWithCursor operation. For initial request,
-// ignore this param or use empty string. For continues requests, use value
+// ignore this param or use nil value. For continues requests, use value
 // from ListWithCursorRes.
-func (p *ListWithCursorPrm) WithCursor(cursor string) *ListWithCursorPrm {
+func (p *ListWithCursorPrm) WithCursor(cursor *Cursor) *ListWithCursorPrm {
 	p.cursor = cursor
 	return p
 }
@@ -51,7 +54,7 @@ func (r ListWithCursorRes) AddressList() []*object.Address {
 }
 
 // Cursor returns cursor for consecutive listing requests.
-func (r ListWithCursorRes) Cursor() string {
+func (r ListWithCursorRes) Cursor() *Cursor {
 	return r.cursor
 }
 
@@ -121,11 +124,11 @@ func (s *Shard) ListWithCursor(prm *ListWithCursorPrm) (*ListWithCursorRes, erro
 // ListWithCursor lists physical objects available in shard starting from
 // cursor. Includes regular, tombstone and storage group objects. Does not
 // include inhumed objects. Use cursor value from response for consecutive requests.
-func ListWithCursor(s *Shard, count uint32, cursor string) ([]*object.Address, string, error) {
+func ListWithCursor(s *Shard, count uint32, cursor *Cursor) ([]*object.Address, *Cursor, error) {
 	prm := new(ListWithCursorPrm).WithCount(count).WithCursor(cursor)
 	res, err := s.ListWithCursor(prm)
 	if err != nil {
-		return nil, "", err
+		return nil, nil, err
 	}
 
 	return res.AddressList(), res.Cursor(), nil