[#211] blobstor: Refactor GetBig parameters and result

Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>

pkg/local_object_storage/blobstor/get_big.go

@@ -11,33 +11,17 @@ import (
 
 // GetBigPrm groups the parameters of GetBig operation.
 type GetBigPrm struct {
-	addr *objectSDK.Address
+	address
 }
 
 // GetBigRes groups resulting values of GetBig operation.
 type GetBigRes struct {
-	obj *object.Object
+	roObject
 }
 
 // ErrObjectNotFound is returns on read operations requested on a missing object.
 var ErrObjectNotFound = errors.New("object not found")
 
-// WithAddress is a GetBig option to set the address of the requested object.
-//
-// Option is required.
-func (p *GetBigPrm) WithAddress(addr *objectSDK.Address) *GetBigPrm {
-	if p != nil {
-		p.addr = addr
-	}
-
-	return p
-}
-
-// Object returns the requested object.
-func (r *GetBigRes) Object() *object.Object {
-	return r.obj
-}
-
 // GetBig reads the object from shallow dir of BLOB storage by address.
 //
 // Returns any error encountered that
@@ -68,7 +52,9 @@ func (b *BlobStor) GetBig(prm *GetBigPrm) (*GetBigRes, error) {
 	}
 
 	return &GetBigRes{
-		obj: obj,
+		roObject: roObject{
+			obj: obj,
+		},
 	}, nil
 }
 

pkg/local_object_storage/blobstor/util.go

@@ -0,0 +1,33 @@
+package blobstor
+
+import (
+	objectSDK "github.com/nspcc-dev/neofs-api-go/pkg/object"
+	"github.com/nspcc-dev/neofs-node/pkg/core/object"
+)
+
+type address struct {
+	addr *objectSDK.Address
+}
+
+// SetAddress sets the address of the requested object.
+func (a *address) SetAddress(addr *objectSDK.Address) {
+	a.addr = addr
+}
+
+type roObject struct {
+	obj *object.Object
+}
+
+// Object returns the object.
+func (o roObject) Object() *object.Object {
+	return o.obj
+}
+
+type rwObject struct {
+	roObject
+}
+
+// SetObject sets the object.
+func (o *rwObject) SetObject(obj *object.Object) {
+	o.obj = obj
+}

pkg/local_object_storage/shard/get.go

@@ -77,10 +77,12 @@ func (s *Shard) Get(prm *GetPrm) (*GetRes, error) {
 	if prm.ln < 0 {
 		// try to read from WriteCache
 		// TODO: implement
-		res, err := s.blobStor.GetBig(
+
-			new(blobstor.GetBigPrm).
+		// form GetBig parameters
-				WithAddress(prm.addr),
+		getBigPrm := new(blobstor.GetBigPrm)
-		)
+		getBigPrm.SetAddress(prm.addr)
+
+		res, err := s.blobStor.GetBig(getBigPrm)
 		if err != nil {
 			if errors.Is(err, blobstor.ErrObjectNotFound) {
 				err = ErrObjectNotFound