[#1523] local_object_storage: Move blobovnicza tree to a separate package

Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>

pkg/local_object_storage/blobstor/blobovniczatree/exists.go

@@ -0,0 +1,38 @@
+package blobovniczatree
+
+import (
+	"path/filepath"
+
+	"github.com/nspcc-dev/neofs-node/pkg/local_object_storage/blobovnicza"
+	oid "github.com/nspcc-dev/neofs-sdk-go/object/id"
+	"go.uber.org/zap"
+)
+
+func (b *Blobovniczas) Exists(addr oid.Address) (bool, error) {
+	activeCache := make(map[string]struct{})
+
+	var prm blobovnicza.GetPrm
+	prm.SetAddress(addr)
+
+	var found bool
+	err := b.iterateSortedLeaves(&addr, func(p string) (bool, error) {
+		dirPath := filepath.Dir(p)
+
+		_, ok := activeCache[dirPath]
+
+		_, err := b.getObjectFromLevel(prm, p, !ok)
+		if err != nil {
+			if !blobovnicza.IsErrNotFound(err) {
+				b.log.Debug("could not get object from level",
+					zap.String("level", p),
+					zap.String("error", err.Error()))
+			}
+		}
+
+		activeCache[dirPath] = struct{}{}
+		found = err == nil
+		return found, nil
+	})
+
+	return found, err
+}