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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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68
pkg/local_object_storage/engine/list.go
View file

@ -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 (
err error
result = make([]*object.Address, 0, prm.count)
)
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 len(cursor) > 0 {
cursorShardID, cursor, err = decodeID(cursor)
if err != nil {
return nil, err
}
if cursor == nil {
cursor = &Cursor{shardID: shardIDs[0]}
}
// 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 {
shardPrm.WithCursor(cursor)
if shardIDs[i] == cursor.shardID {
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()
cursorShardID = shardIDs[i]
cursor.shardCursor = res.Cursor()
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
}