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

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Signed-off-by: Alex Vanin <alexey@nspcc.ru>
This commit is contained in:
Alex Vanin 2021-11-11 17:27:11 +03:00 • committed by Alex Vanin
parent 164cd10af8
commit aa9ce8a853
4 changed files with 71 additions and 122 deletions
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91
pkg/local_object_storage/metabase/list.go
View file

@ -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'
cursorPrefixTombstone = 't'
cursorPrefixSG = 's'
cursorBucketPrimary = iota
cursorBucketTombstone
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) {
threshold := len(cursor) == 0 // 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)
}
}
func (db *DB) listWithCursor(tx *bbolt.Tx, count int, cursor *Cursor) ([]*object.Address, *Cursor, error) {
threshold := cursor == nil // threshold is a flag to ignore cursor
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},
{tombstoneBucketName(containerID), cursorPrefixTombstone},
{storageGroupBucketName(containerID), cursorPrefixSG},
{primaryBucketName(containerID), cursorBucketPrimary},
{tombstoneBucketName(containerID), cursorBucketTombstone},
{storageGroupBucketName(containerID), cursorBucketSG},
}
for _, lb := range lookupBuckets {
if !threshold && cursorPrefix != lb.prefix {
continue // start from the bucket, specified in the cursor prefix
if !threshold && cursor.bucket != lb.bucket {
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(seekKey))
c.Seek([]byte(cursor.address.ObjectID().String()))
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++
}