package meta import ( "errors" "strings" cid "github.com/nspcc-dev/neofs-sdk-go/container/id" addressSDK "github.com/nspcc-dev/neofs-sdk-go/object/address" "go.etcd.io/bbolt" ) // ErrEndOfListing is returned from object listing with cursor // when storage can't return any more objects after provided // cursor. Use nil cursor object to start listing again. var ErrEndOfListing = errors.New("end of object listing") // Cursor is a type for continuous object listing. type Cursor struct { bucketName []byte inBucketOffset []byte } // ListPrm contains parameters for ListWithCursor operation. type ListPrm struct { count int cursor *Cursor } // WithCount sets maximum amount of addresses that ListWithCursor should return. func (l *ListPrm) WithCount(count uint32) *ListPrm { l.count = int(count) return l } // WithCursor sets cursor for ListWithCursor operation. For initial request // ignore this param or use nil value. For consecutive requests, use value // from ListRes. func (l *ListPrm) WithCursor(cursor *Cursor) *ListPrm { l.cursor = cursor return l } // ListRes contains values returned from ListWithCursor operation. type ListRes struct { addrList []*addressSDK.Address cursor *Cursor } // AddressList returns addresses selected by ListWithCursor operation. func (l ListRes) AddressList() []*addressSDK.Address { return l.addrList } // Cursor returns cursor for consecutive listing requests. func (l ListRes) Cursor() *Cursor { return l.cursor } // ListWithCursor lists physical objects available in metabase starting from // cursor. Includes objects of all types. Does not include inhumed objects. // Use cursor value from response for consecutive requests. // // Returns ErrEndOfListing if there are no more objects to return or count // parameter set to zero. func ListWithCursor(db *DB, count uint32, cursor *Cursor) ([]*addressSDK.Address, *Cursor, error) { r, err := db.ListWithCursor(new(ListPrm).WithCount(count).WithCursor(cursor)) if err != nil { return nil, nil, err } return r.AddressList(), r.Cursor(), nil } // ListWithCursor lists physical objects available in metabase starting from // cursor. Includes objects of all types. Does not include inhumed objects. // Use cursor value from response for consecutive requests. // // Returns ErrEndOfListing if there are no more objects to return or count // parameter set to zero. func (db *DB) ListWithCursor(prm *ListPrm) (res *ListRes, err error) { err = db.boltDB.View(func(tx *bbolt.Tx) error { res = new(ListRes) res.addrList, res.cursor, err = db.listWithCursor(tx, prm.count, prm.cursor) return err }) return res, err } func (db *DB) listWithCursor(tx *bbolt.Tx, count int, cursor *Cursor) ([]*addressSDK.Address, *Cursor, error) { threshold := cursor == nil // threshold is a flag to ignore cursor result := make([]*addressSDK.Address, 0, count) var bucketName []byte c := tx.Cursor() name, _ := c.First() if !threshold { name, _ = c.Seek(cursor.bucketName) } loop: for ; name != nil; name, _ = c.Next() { containerID, postfix := parseContainerIDWithPostfix(name) if containerID == nil { continue } switch postfix { case "", storageGroupPostfix, bucketNameSuffixLockers, tombstonePostfix: default: continue } prefix := containerID.String() + "/" result, cursor = selectNFromBucket(tx, name, prefix, result, count, cursor, threshold) bucketName = name if len(result) >= count { break loop } // set threshold flag after first `selectNFromBucket` invocation // first invocation must look for cursor object threshold = true } if len(result) == 0 { return nil, nil, ErrEndOfListing } // new slice is much faster but less memory efficient // we need to copy, because bucketName exists during bbolt tx cursor.bucketName = make([]byte, len(bucketName)) copy(cursor.bucketName, bucketName) return result, cursor, nil } // selectNFromBucket similar to selectAllFromBucket but uses cursor to find // object to start selecting from. Ignores inhumed objects. func selectNFromBucket(tx *bbolt.Tx, name []byte, // bucket name prefix string, // string of CID, optimization to []*addressSDK.Address, // listing result limit int, // stop listing at `limit` items in result cursor *Cursor, // start from cursor object threshold bool, // ignore cursor and start immediately ) ([]*addressSDK.Address, *Cursor) { bkt := tx.Bucket(name) if bkt == nil { return to, cursor } if cursor == nil { cursor = new(Cursor) } count := len(to) c := bkt.Cursor() k, _ := c.First() offset := cursor.inBucketOffset if !threshold { c.Seek(offset) k, _ = c.Next() // we are looking for objects _after_ the cursor } for ; k != nil; k, _ = c.Next() { if count >= limit { break } a := addressSDK.NewAddress() if err := a.Parse(prefix + string(k)); err != nil { break } offset = k if inGraveyard(tx, a) > 0 { continue } to = append(to, a) count++ } // new slice is much faster but less memory efficient // we need to copy, because offset exists during bbolt tx cursor.inBucketOffset = make([]byte, len(offset)) copy(cursor.inBucketOffset, offset) return to, cursor } func parseContainerIDWithPostfix(name []byte) (*cid.ID, string) { var ( containerID = cid.New() containerIDStr = string(name) postfix string ) ind := strings.Index(string(name), invalidBase58String) if ind > 0 { postfix = containerIDStr[ind:] containerIDStr = containerIDStr[:ind] } if err := containerID.Parse(containerIDStr); err != nil { return nil, "" } return containerID, postfix }