[#170] oid, cid: Refactor and document package functionality

Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>

audit/result.go

@@ -75,20 +75,29 @@ func (r *Result) ForEpoch(epoch uint64) {
 // Container returns identifier of the container with which the data audit Result
 // is associated.
 //
-// Returns nil if container is not specified. Zero Result has nil container.
+// Returns zero ID if container is not specified. Zero Result has zero container.
-// Return value MUST NOT be mutated: to do this, first make a copy.
 //
 // See also ForContainer.
-func (r Result) Container() *cid.ID {
+func (r Result) Container() cid.ID {
-	return cid.NewFromV2(r.v2.GetContainerID())
+	var cID cid.ID
+
+	cidV2 := r.v2.GetContainerID()
+	if cidV2 != nil {
+		_ = cID.ReadFromV2(*cidV2)
 	}
 
-// ForContainer returns identifier of the container with which the data audit Result
+	return cID
+}
+
+// ForContainer sets identifier of the container with which the data audit Result
 // is associated.
 //
 // See also Container.
 func (r *Result) ForContainer(cnr cid.ID) {
-	r.v2.SetContainerID(cnr.ToV2())
+	var cidV2 refs.ContainerID
+	cnr.WriteToV2(&cidV2)
+
+	r.v2.SetContainerID(&cidV2)
 }
 
 // AuditorKey returns public key of the auditing NeoFS Inner Ring node in
@@ -174,8 +183,12 @@ func (r *Result) SetRetriesPoR(v uint32) {
 func (r Result) IteratePassedStorageGroups(f func(oid.ID) bool) {
 	r2 := r.v2.GetPassSG()
 
+	var id oid.ID
+
 	for i := range r2 {
-		if !f(*oid.NewIDFromV2(&r2[i])) {
+		_ = id.ReadFromV2(r2[i])
+
+		if !f(id) {
 			return
 		}
 	}
@@ -186,7 +199,10 @@ func (r Result) IteratePassedStorageGroups(f func(oid.ID) bool) {
 //
 // See also IteratePassedStorageGroups.
 func (r *Result) SubmitPassedStorageGroup(sg oid.ID) {
-	r.v2.SetPassSG(append(r.v2.GetPassSG(), *sg.ToV2()))
+	var idV2 refs.ObjectID
+	sg.WriteToV2(&idV2)
+
+	r.v2.SetPassSG(append(r.v2.GetPassSG(), idV2))
 }
 
 // IterateFailedStorageGroups is similar to IteratePassedStorageGroups but for failed groups.
@@ -194,9 +210,11 @@ func (r *Result) SubmitPassedStorageGroup(sg oid.ID) {
 // See also SubmitFailedStorageGroup.
 func (r Result) IterateFailedStorageGroups(f func(oid.ID) bool) {
 	v := r.v2.GetFailSG()
+	var id oid.ID
 
 	for i := range v {
-		if !f(*oid.NewIDFromV2(&v[i])) {
+		_ = id.ReadFromV2(v[i])
+		if !f(id) {
 			return
 		}
 	}
@@ -206,7 +224,10 @@ func (r Result) IterateFailedStorageGroups(f func(oid.ID) bool) {
 //
 // See also IterateFailedStorageGroups.
 func (r *Result) SubmitFailedStorageGroup(sg oid.ID) {
-	r.v2.SetFailSG(append(r.v2.GetFailSG(), *sg.ToV2()))
+	var idV2 refs.ObjectID
+	sg.WriteToV2(&idV2)
+
+	r.v2.SetFailSG(append(r.v2.GetFailSG(), idV2))
 }
 
 // Hits returns number of sampled objects under audit placed

audit/result_test.go

@@ -66,7 +66,7 @@ func TestResultData(t *testing.T) {
 	countFailNodes := func(f func([]byte)) int { return countNodes(false, f) }
 
 	require.Zero(t, r.Epoch())
-	require.Nil(t, r.Container())
+	require.True(t, r.Container().Empty())
 	require.Nil(t, r.AuditorKey())
 	require.False(t, r.Completed())
 	require.Zero(t, r.RequestsPoR())
@@ -81,7 +81,7 @@ func TestResultData(t *testing.T) {
 	require.Equal(t, epoch, r.Epoch())
 
 	cnr := cidtest.ID()
-	r.ForContainer(*cnr)
+	r.ForContainer(cnr)
 	require.Equal(t, cnr, r.Container())
 
 	key := []byte{1, 2, 3}
@@ -99,32 +99,32 @@ func TestResultData(t *testing.T) {
 	r.SetRetriesPoR(retries)
 	require.Equal(t, retries, r.RetriesPoR())
 
-	passSG1, passSG2 := *oidtest.ID(), *oidtest.ID()
+	passSG1, passSG2 := oidtest.ID(), oidtest.ID()
 	r.SubmitPassedStorageGroup(passSG1)
 	r.SubmitPassedStorageGroup(passSG2)
 
 	called1, called2 := false, false
 
 	require.EqualValues(t, 2, countPassSG(func(id oid.ID) {
-		if id.Equal(&passSG1) {
+		if id.Equals(passSG1) {
 			called1 = true
-		} else if id.Equal(&passSG2) {
+		} else if id.Equals(passSG2) {
 			called2 = true
 		}
 	}))
 	require.True(t, called1)
 	require.True(t, called2)
 
-	failSG1, failSG2 := *oidtest.ID(), *oidtest.ID()
+	failSG1, failSG2 := oidtest.ID(), oidtest.ID()
 	r.SubmitFailedStorageGroup(failSG1)
 	r.SubmitFailedStorageGroup(failSG2)
 
 	called1, called2 = false, false
 
 	require.EqualValues(t, 2, countFailSG(func(id oid.ID) {
-		if id.Equal(&failSG1) {
+		if id.Equals(failSG1) {
 			called1 = true
-		} else if id.Equal(&failSG2) {
+		} else if id.Equals(failSG2) {
 			called2 = true
 		}
 	}))

audit/test/generate.go

@@ -10,7 +10,7 @@ import (
 func Result() *audit.Result {
 	var x audit.Result
 
-	x.ForContainer(*cidtest.ID())
+	x.ForContainer(cidtest.ID())
 	x.SetAuditorKey([]byte("key"))
 	x.Complete()
 	x.ForEpoch(44)
@@ -27,10 +27,10 @@ func Result() *audit.Result {
 		[]byte("node3"),
 		[]byte("node4"),
 	})
-	x.SubmitPassedStorageGroup(*oidtest.ID())
+	x.SubmitPassedStorageGroup(oidtest.ID())
-	x.SubmitPassedStorageGroup(*oidtest.ID())
+	x.SubmitPassedStorageGroup(oidtest.ID())
-	x.SubmitFailedStorageGroup(*oidtest.ID())
+	x.SubmitFailedStorageGroup(oidtest.ID())
-	x.SubmitFailedStorageGroup(*oidtest.ID())
+	x.SubmitFailedStorageGroup(oidtest.ID())
 
 	return &x
 }

client/container.go

@@ -4,6 +4,7 @@ import (
 	"context"
 
 	v2container "github.com/nspcc-dev/neofs-api-go/v2/container"
+	"github.com/nspcc-dev/neofs-api-go/v2/refs"
 	rpcapi "github.com/nspcc-dev/neofs-api-go/v2/rpc"
 	"github.com/nspcc-dev/neofs-api-go/v2/rpc/client"
 	v2session "github.com/nspcc-dev/neofs-api-go/v2/session"
@@ -121,7 +122,17 @@ func (c *Client) ContainerPut(ctx context.Context, prm PrmContainerPut) (*ResCon
 	}
 	cc.result = func(r responseV2) {
 		resp := r.(*v2container.PutResponse)
-		res.setID(cid.NewFromV2(resp.GetBody().GetContainerID()))
+		var cID *cid.ID
+
+		cidV2 := resp.GetBody().GetContainerID()
+		if cidV2 != nil {
+			var c cid.ID
+			_ = c.ReadFromV2(*cidV2)
+
+			cID = &c
+		}
+
+		res.setID(cID)
 	}
 
 	// process call
@@ -187,9 +198,12 @@ func (c *Client) ContainerGet(ctx context.Context, prm PrmContainerGet) (*ResCon
 		panic(panicMsgMissingContainer)
 	}
 
+	var cidV2 refs.ContainerID
+	prm.id.WriteToV2(&cidV2)
+
 	// form request body
 	reqBody := new(v2container.GetRequestBody)
-	reqBody.SetContainerID(prm.id.ToV2())
+	reqBody.SetContainerID(&cidV2)
 
 	// form request
 	var req v2container.GetRequest
@@ -322,7 +336,7 @@ func (c *Client) ContainerList(ctx context.Context, prm PrmContainerList) (*ResC
 		ids := make([]cid.ID, len(resp.GetBody().GetContainerIDs()))
 
 		for i, cidV2 := range resp.GetBody().GetContainerIDs() {
-			ids[i] = *cid.NewFromV2(&cidV2)
+			_ = ids[i].ReadFromV2(cidV2)
 		}
 
 		res.setContainers(ids)
@@ -400,9 +414,12 @@ func (c *Client) ContainerDelete(ctx context.Context, prm PrmContainerDelete) (*
 		panic(panicMsgMissingContainer)
 	}
 
+	var cidV2 refs.ContainerID
+	prm.id.WriteToV2(&cidV2)
+
 	// form request body
 	reqBody := new(v2container.DeleteRequestBody)
-	reqBody.SetContainerID(prm.id.ToV2())
+	reqBody.SetContainerID(&cidV2)
 
 	signWrapper := delContainerSignWrapper{body: reqBody}
 
@@ -504,9 +521,12 @@ func (c *Client) ContainerEACL(ctx context.Context, prm PrmContainerEACL) (*ResC
 		panic(panicMsgMissingContainer)
 	}
 
+	var cidV2 refs.ContainerID
+	prm.id.WriteToV2(&cidV2)
+
 	// form request body
 	reqBody := new(v2container.GetExtendedACLRequestBody)
-	reqBody.SetContainerID(prm.id.ToV2())
+	reqBody.SetContainerID(&cidV2)
 
 	// form request
 	var req v2container.GetExtendedACLRequest

client/object_delete.go

@@ -52,13 +52,19 @@ func (x *PrmObjectDelete) WithBearerToken(t bearer.Token) {
 // FromContainer specifies NeoFS container of the object.
 // Required parameter.
 func (x *PrmObjectDelete) FromContainer(id cid.ID) {
-	x.addr.SetContainerID(id.ToV2())
+	var cidV2 v2refs.ContainerID
+	id.WriteToV2(&cidV2)
+
+	x.addr.SetContainerID(&cidV2)
 }
 
 // ByID specifies identifier of the requested object.
 // Required parameter.
 func (x *PrmObjectDelete) ByID(id oid.ID) {
-	x.addr.SetObjectID(id.ToV2())
+	var idV2 v2refs.ObjectID
+	id.WriteToV2(&idV2)
+
+	x.addr.SetObjectID(&idV2)
 }
 
 // UseKey specifies private key to sign the requests.
@@ -91,7 +97,7 @@ type ResObjectDelete struct {
 // Returns false if ID is missing (not read).
 func (x ResObjectDelete) ReadTombstoneID(dst *oid.ID) bool {
 	if x.idTomb != nil {
-		*dst = *oid.NewIDFromV2(x.idTomb) // need smth better
+		_ = dst.ReadFromV2(*x.idTomb)
 		return true
 	}
 

client/object_get.go

@@ -36,10 +36,10 @@ type prmObjectRead struct {
 	bearer    bearer.Token
 
 	cnrSet bool
-	cnr    cid.ID
+	cnrID  cid.ID
 
 	objSet bool
-	obj    oid.ID
+	objID  oid.ID
 }
 
 func (x prmObjectRead) writeToMetaHeader(h *v2session.RequestMetaHeader) {
@@ -94,14 +94,14 @@ func (x *prmObjectRead) WithBearerToken(t bearer.Token) {
 // FromContainer specifies NeoFS container of the object.
 // Required parameter.
 func (x *prmObjectRead) FromContainer(id cid.ID) {
-	x.cnr = id
+	x.cnrID = id
 	x.cnrSet = true
 }
 
 // ByID specifies identifier of the requested object.
 // Required parameter.
 func (x *prmObjectRead) ByID(id oid.ID) {
-	x.obj = id
+	x.objID = id
 	x.objSet = true
 }
 
@@ -318,10 +318,17 @@ func (c *Client) ObjectGetInit(ctx context.Context, prm PrmObjectGet) (*ObjectRe
 		panic("missing object")
 	}
 
-	var addr v2refs.Address
+	var (
+		addr  v2refs.Address
+		oidV2 v2refs.ObjectID
+		cidV2 v2refs.ContainerID
+	)
 
-	addr.SetContainerID(prm.cnr.ToV2())
+	prm.objID.WriteToV2(&oidV2)
-	addr.SetObjectID(prm.obj.ToV2())
+	prm.cnrID.WriteToV2(&cidV2)
+
+	addr.SetContainerID(&cidV2)
+	addr.SetObjectID(&oidV2)
 
 	// form request body
 	var body v2object.GetRequestBody
@@ -411,7 +418,7 @@ func (x *ResObjectHead) ReadHeader(dst *object.Object) bool {
 	objv2.SetSignature(x.hdr.GetSignature())
 
 	obj := object.NewFromV2(&objv2)
-	obj.SetID(&x.idObj)
+	obj.SetID(x.idObj)
 
 	*dst = *obj
 
@@ -449,16 +456,23 @@ func (c *Client) ObjectHead(ctx context.Context, prm PrmObjectHead) (*ResObjectH
 		panic("missing object")
 	}
 
-	var addr v2refs.Address
+	var (
+		addrV2 v2refs.Address
+		oidV2  v2refs.ObjectID
+		cidV2  v2refs.ContainerID
+	)
 
-	addr.SetContainerID(prm.cnr.ToV2())
+	prm.objID.WriteToV2(&oidV2)
-	addr.SetObjectID(prm.obj.ToV2())
+	prm.cnrID.WriteToV2(&cidV2)
+
+	addrV2.SetContainerID(&cidV2)
+	addrV2.SetObjectID(&oidV2)
 
 	// form request body
 	var body v2object.HeadRequestBody
 
 	body.SetRaw(prm.raw)
-	body.SetAddress(&addr)
+	body.SetAddress(&addrV2)
 
 	// form meta header
 	var meta v2session.RequestMetaHeader
@@ -478,7 +492,7 @@ func (c *Client) ObjectHead(ctx context.Context, prm PrmObjectHead) (*ResObjectH
 		res ResObjectHead
 	)
 
-	res.idObj = prm.obj
+	res.idObj = prm.objID
 
 	if prm.keySet {
 		c.initCallContextWithoutKey(&cc)
@@ -715,10 +729,17 @@ func (c *Client) ObjectRangeInit(ctx context.Context, prm PrmObjectRange) (*Obje
 		panic("zero range length")
 	}
 
-	var addr v2refs.Address
+	var (
+		addrV2 v2refs.Address
+		oidV2  v2refs.ObjectID
+		cidV2  v2refs.ContainerID
+	)
 
-	addr.SetContainerID(prm.cnr.ToV2())
+	prm.objID.WriteToV2(&oidV2)
-	addr.SetObjectID(prm.obj.ToV2())
+	prm.cnrID.WriteToV2(&cidV2)
+
+	addrV2.SetContainerID(&cidV2)
+	addrV2.SetObjectID(&oidV2)
 
 	var rng v2object.Range
 
@@ -729,7 +750,7 @@ func (c *Client) ObjectRangeInit(ctx context.Context, prm PrmObjectRange) (*Obje
 	var body v2object.GetRangeRequestBody
 
 	body.SetRaw(prm.raw)
-	body.SetAddress(&addr)
+	body.SetAddress(&addrV2)
 	body.SetRange(&rng)
 
 	// form meta header

client/object_hash.go

@@ -55,13 +55,19 @@ func (x *PrmObjectHash) WithBearerToken(t bearer.Token) {
 // FromContainer specifies NeoFS container of the object.
 // Required parameter.
 func (x *PrmObjectHash) FromContainer(id cid.ID) {
-	x.addr.SetContainerID(id.ToV2())
+	var cidV2 v2refs.ContainerID
+	id.WriteToV2(&cidV2)
+
+	x.addr.SetContainerID(&cidV2)
 }
 
 // ByID specifies identifier of the requested object.
 // Required parameter.
 func (x *PrmObjectHash) ByID(id oid.ID) {
-	x.addr.SetObjectID(id.ToV2())
+	var idV2 v2refs.ObjectID
+	id.WriteToV2(&idV2)
+
+	x.addr.SetObjectID(&idV2)
 }
 
 // SetRangeList sets list of ranges in (offset, length) pair format.

client/object_put.go

@@ -37,7 +37,7 @@ func (x *ResObjectPut) ReadStoredObjectID(id *oid.ID) bool {
 		return false
 	}
 
-	*id = *oid.NewIDFromV2(idv2) // need smth better
+	_ = id.ReadFromV2(*idv2)
 
 	return true
 }

client/object_search.go

@@ -34,7 +34,7 @@ type PrmObjectSearch struct {
 	bearer    bearer.Token
 
 	cnrSet bool
-	cnr    cid.ID
+	cnrID  cid.ID
 
 	filters object.SearchFilters
 }
@@ -68,7 +68,7 @@ func (x *PrmObjectSearch) WithBearerToken(t bearer.Token) {
 // InContainer specifies the container in which to look for objects.
 // Required parameter.
 func (x *PrmObjectSearch) InContainer(id cid.ID) {
-	x.cnr = id
+	x.cnrID = id
 	x.cnrSet = true
 }
 
@@ -131,7 +131,7 @@ func (x *ObjectListReader) Read(buf []oid.ID) (int, bool) {
 	}
 
 	for i := 0; i < read; i++ {
-		buf[i] = *oid.NewIDFromV2(&x.tail[i]) // need smth better
+		_ = buf[i].ReadFromV2(x.tail[i])
 	}
 
 	x.tail = x.tail[read:]
@@ -165,7 +165,7 @@ func (x *ObjectListReader) Read(buf []oid.ID) (int, bool) {
 		}
 
 		for i = 0; i < ln; i++ {
-			buf[read+i] = *oid.NewIDFromV2(&ids[i]) // need smth better
+			_ = buf[read+i].ReadFromV2(ids[i])
 		}
 
 		read += ln
@@ -244,10 +244,15 @@ func (c *Client) ObjectSearchInit(ctx context.Context, prm PrmObjectSearch) (*Ob
 	}
 
 	// form request body
-	var body v2object.SearchRequestBody
+	var (
+		body  v2object.SearchRequestBody
+		cidV2 v2refs.ContainerID
+	)
+
+	prm.cnrID.WriteToV2(&cidV2)
 
 	body.SetVersion(1)
-	body.SetContainerID(prm.cnr.ToV2())
+	body.SetContainerID(&cidV2)
 	body.SetFilters(prm.filters.ToV2())
 
 	// form meta header

client/object_search_test.go

@@ -17,7 +17,7 @@ import (
 func TestObjectSearch(t *testing.T) {
 	ids := make([]oid.ID, 20)
 	for i := range ids {
-		ids[i] = *oidtest.ID()
+		ids[i] = oidtest.ID()
 	}
 
 	resp, setID := testListReaderResponse(t)
@@ -88,7 +88,7 @@ func TestObjectSearch(t *testing.T) {
 func TestObjectIterate(t *testing.T) {
 	ids := make([]oid.ID, 3)
 	for i := range ids {
-		ids[i] = *oidtest.ID()
+		ids[i] = oidtest.ID()
 	}
 
 	t.Run("iterate all sequence", func(t *testing.T) {
@@ -176,8 +176,11 @@ func testListReaderResponse(t *testing.T) (*ObjectListReader, func(id []oid.ID)
 		resp.SetBody(new(object.SearchResponseBody))
 
 		v2id := make([]refs.ObjectID, len(id))
+		var oidV2 refs.ObjectID
+
 		for i := range id {
-			v2id[i] = *id[i].ToV2()
+			id[i].WriteToV2(&oidV2)
+			v2id[i] = oidV2
 		}
 		resp.GetBody().SetIDList(v2id)
 		err := signatureV2.SignServiceMessage(&p.PrivateKey, resp)

container/announcement.go

@@ -2,6 +2,7 @@ package container
 
 import (
 	"github.com/nspcc-dev/neofs-api-go/v2/container"
+	"github.com/nspcc-dev/neofs-api-go/v2/refs"
 	cid "github.com/nspcc-dev/neofs-sdk-go/container/id"
 )
 
@@ -38,15 +39,25 @@ func (a *UsedSpaceAnnouncement) SetEpoch(epoch uint64) {
 }
 
 // ContainerID of the announcement.
-func (a *UsedSpaceAnnouncement) ContainerID() *cid.ID {
+func (a *UsedSpaceAnnouncement) ContainerID() (cID cid.ID) {
-	return cid.NewFromV2(
+	v2 := (*container.UsedSpaceAnnouncement)(a)
-		(*container.UsedSpaceAnnouncement)(a).GetContainerID(),
+
-	)
+	cidV2 := v2.GetContainerID()
+	if cidV2 == nil {
+		return
+	}
+
+	_ = cID.ReadFromV2(*cidV2)
+
+	return
 }
 
 // SetContainerID sets announcement container value.
-func (a *UsedSpaceAnnouncement) SetContainerID(cid *cid.ID) {
+func (a *UsedSpaceAnnouncement) SetContainerID(cnr cid.ID) {
-	(*container.UsedSpaceAnnouncement)(a).SetContainerID(cid.ToV2())
+	var cidV2 refs.ContainerID
+	cnr.WriteToV2(&cidV2)
+
+	(*container.UsedSpaceAnnouncement)(a).SetContainerID(&cidV2)
 }
 
 // UsedSpace in container.

container/announcement_test.go

@@ -46,9 +46,12 @@ func TestAnnouncement(t *testing.T) {
 
 		newA := container.NewAnnouncementFromV2(v2)
 
+		var cID cid.ID
+		_ = cID.ReadFromV2(*newCID)
+
 		require.Equal(t, newEpoch, newA.Epoch())
 		require.Equal(t, newUsedSpace, newA.UsedSpace())
-		require.Equal(t, cid.NewFromV2(newCID), newA.ContainerID())
+		require.Equal(t, cID, newA.ContainerID())
 	})
 }
 
@@ -79,7 +82,7 @@ func TestUsedSpaceAnnouncement_ToV2(t *testing.T) {
 		// check initial values
 		require.Zero(t, announcement.Epoch())
 		require.Zero(t, announcement.UsedSpace())
-		require.Nil(t, announcement.ContainerID())
+		require.True(t, announcement.ContainerID().Empty())
 
 		// convert to v2 message
 		announcementV2 := announcement.ToV2()

container/container.go

@@ -87,13 +87,13 @@ func NewContainerFromV2(c *container.Container) *Container {
 
 // CalculateID calculates container identifier
 // based on its structure.
-func CalculateID(c *Container) *cid.ID {
+func CalculateID(c *Container) cid.ID {
 	data, err := c.ToV2().StableMarshal(nil)
 	if err != nil {
 		panic(err)
 	}
 
-	id := cid.New()
+	var id cid.ID
 	id.SetSHA256(sha256.Sum256(data))
 
 	return id

container/id/doc.go

@@ -0,0 +1,8 @@
+/*
+Package cid provides primitives to work with container identification in NeoFS.
+
+Using package types in an application is recommended to potentially work with
+different protocol versions with which these types are compatible.
+
+*/
+package cid

container/id/id.go

@@ -1,90 +1,120 @@
 package cid
 
 import (
-	"bytes"
 	"crypto/sha256"
-	"errors"
+	"fmt"
 
 	"github.com/mr-tron/base58"
 	"github.com/nspcc-dev/neofs-api-go/v2/refs"
 )
 
-// ID represents v2-compatible container identifier.
+// ID represents NeoFS container identifier.
-type ID refs.ContainerID
-
-// NewFromV2 wraps v2 ContainerID message to ID.
 //
-// Nil refs.ContainerID converts to nil.
+// ID is mutually compatible with github.com/nspcc-dev/neofs-api-go/v2/refs.ContainerID
-func NewFromV2(idV2 *refs.ContainerID) *ID {
+// message. See ReadFromV2 / WriteToV2 methods.
-	return (*ID)(idV2)
-}
-
-// New creates and initializes blank ID.
 //
-// Defaults:
+// Instances can be created using built-in var declaration.
-//  - value: nil.
-func New() *ID {
-	return NewFromV2(new(refs.ContainerID))
-}
-
-// SetSHA256 sets container identifier value to SHA256 checksum of container body.
-func (id *ID) SetSHA256(v [sha256.Size]byte) {
-	(*refs.ContainerID)(id).SetValue(v[:])
-}
-
-// ToV2 returns the v2 container ID message.
 //
-// Nil ID converts to nil.
+// Note that direct typecast is not safe and may result in loss of compatibility:
-func (id *ID) ToV2() *refs.ContainerID {
+// 	_ = ID([32]byte) // not recommended
-	return (*refs.ContainerID)(id)
+type ID [sha256.Size]byte
-}
 
-// Equal returns true if identifiers are identical.
+// ReadFromV2 reads ID from the refs.ContainerID message.
-func (id *ID) Equal(id2 *ID) bool {
+// Returns an error if the message is malformed according
-	return bytes.Equal(
+// to the NeoFS API V2 protocol.
-		(*refs.ContainerID)(id).GetValue(),
-		(*refs.ContainerID)(id2).GetValue(),
-	)
-}
-
-// Parse parses string representation of ID.
 //
-// Returns error if s is not a base58 encoded
+// See also WriteToV2.
-// ID data.
+func (id *ID) ReadFromV2(m refs.ContainerID) error {
-func (id *ID) Parse(s string) error {
+	return id.Decode(m.GetValue())
-	data, err := base58.Decode(s)
-	if err != nil {
-		return err
-	} else if len(data) != sha256.Size {
-		return errors.New("incorrect format of the string container ID")
 }
 
-	(*refs.ContainerID)(id).SetValue(data)
+// WriteToV2 writes ID to the refs.ContainerID message.
+// The message must not be nil.
+//
+// See also ReadFromV2.
+func (id ID) WriteToV2(m *refs.ContainerID) {
+	m.SetValue(id[:])
+}
+
+// Encode encodes ID into 32 bytes of dst. Panics if
+// dst length is less than 32.
+//
+// Zero ID is all zeros.
+//
+// See also Decode.
+func (id ID) Encode(dst []byte) {
+	if l := len(dst); l < sha256.Size {
+		panic(fmt.Sprintf("destination length is less than %d bytes: %d", sha256.Size, l))
+	}
+
+	copy(dst, id[:])
+}
+
+// Decode decodes src bytes into ID.
+//
+// Decode expects that src has 32 bytes length. If the input is malformed,
+// Decode returns an error describing format violation. In this case ID
+// remains unchanged.
+//
+// Decode doesn't mutate src.
+//
+// See also Encode.
+func (id *ID) Decode(src []byte) error {
+	if len(src) != sha256.Size {
+		return fmt.Errorf("invalid length %d", len(src))
+	}
+
+	copy(id[:], src)
 
 	return nil
 }
 
-// String returns base58 string representation of ID.
+// SetSHA256 sets container identifier value to SHA256 checksum of container structure.
-func (id *ID) String() string {
+func (id *ID) SetSHA256(v [sha256.Size]byte) {
-	return base58.Encode((*refs.ContainerID)(id).GetValue())
+	copy(id[:], v[:])
 }
 
-// Marshal marshals ID into a protobuf binary form.
+// Equals defines a comparison relation between two ID instances.
-func (id *ID) Marshal() ([]byte, error) {
+//
-	return (*refs.ContainerID)(id).StableMarshal(nil)
+// Note that comparison using '==' operator is not recommended since it MAY result
+// in loss of compatibility.
+func (id ID) Equals(id2 ID) bool {
+	return id == id2
 }
 
-// Unmarshal unmarshals protobuf binary representation of ID.
+// EncodeToString encodes ID into NeoFS API protocol string.
-func (id *ID) Unmarshal(data []byte) error {
+//
-	return (*refs.ContainerID)(id).Unmarshal(data)
+// Zero ID is base58 encoding of 32 zeros.
+//
+// See also DecodeString.
+func (id ID) EncodeToString() string {
+	return base58.Encode(id[:])
 }
 
-// MarshalJSON encodes ID to protobuf JSON format.
+// DecodeString decodes string into ID according to NeoFS API protocol. Returns
-func (id *ID) MarshalJSON() ([]byte, error) {
+// an error if s is malformed.
-	return (*refs.ContainerID)(id).MarshalJSON()
+//
+// See also DecodeString.
+func (id *ID) DecodeString(s string) error {
+	data, err := base58.Decode(s)
+	if err != nil {
+		return fmt.Errorf("decode base58: %w", err)
 	}
 
-// UnmarshalJSON decodes ID from protobuf JSON format.
+	return id.Decode(data)
-func (id *ID) UnmarshalJSON(data []byte) error {
+}
-	return (*refs.ContainerID)(id).UnmarshalJSON(data)
+
+// String implements fmt.Stringer.
+//
+// String is designed to be human-readable, and its format MAY differ between
+// SDK versions. String MAY return same result as EncodeToString. String MUST NOT
+// be used to encode ID into NeoFS protocol string.
+func (id ID) String() string {
+	return id.EncodeToString()
+}
+
+// Empty returns true if it is called on
+// zero container ID.
+func (id ID) Empty() bool {
+	return id == ID{}
 }

container/id/id_test.go

@@ -5,6 +5,7 @@ import (
 	"math/rand"
 	"testing"
 
+	"github.com/mr-tron/base58"
 	"github.com/nspcc-dev/neofs-api-go/v2/refs"
 	cid "github.com/nspcc-dev/neofs-sdk-go/container/id"
 	cidtest "github.com/nspcc-dev/neofs-sdk-go/container/id/test"
@@ -16,30 +17,32 @@ func randSHA256Checksum() (cs [sha256.Size]byte) {
 	return
 }
 
+const emptyID = "11111111111111111111111111111111"
+
 func TestID_ToV2(t *testing.T) {
-	t.Run("non-nil", func(t *testing.T) {
+	t.Run("non-zero", func(t *testing.T) {
 		checksum := randSHA256Checksum()
 
 		id := cidtest.IDWithChecksum(checksum)
 
-		idV2 := id.ToV2()
+		var idV2 refs.ContainerID
+		id.WriteToV2(&idV2)
 
-		require.Equal(t, id, cid.NewFromV2(idV2))
+		var newID cid.ID
+		require.NoError(t, newID.ReadFromV2(idV2))
+
+		require.Equal(t, id, newID)
 		require.Equal(t, checksum[:], idV2.GetValue())
 	})
 
-	t.Run("nil", func(t *testing.T) {
+	t.Run("zero", func(t *testing.T) {
-		var x *cid.ID
+		var (
+			x  cid.ID
+			v2 refs.ContainerID
+		)
 
-		require.Nil(t, x.ToV2())
+		x.WriteToV2(&v2)
-	})
+		require.Equal(t, emptyID, base58.Encode(v2.GetValue()))
-
-	t.Run("default values", func(t *testing.T) {
-		id := cid.New()
-
-		// convert to v2 message
-		cidV2 := id.ToV2()
-		require.Nil(t, cidV2.GetValue())
 	})
 }
 
@@ -49,57 +52,57 @@ func TestID_Equal(t *testing.T) {
 	id1 := cidtest.IDWithChecksum(cs)
 	id2 := cidtest.IDWithChecksum(cs)
 
-	require.True(t, id1.Equal(id2))
+	require.True(t, id1.Equals(id2))
 
 	id3 := cidtest.ID()
 
-	require.False(t, id1.Equal(id3))
+	require.False(t, id1.Equals(id3))
 }
 
 func TestID_String(t *testing.T) {
-	t.Run("Parse/String", func(t *testing.T) {
+	t.Run("DecodeString/EncodeToString", func(t *testing.T) {
 		id := cidtest.ID()
-		id2 := cid.New()
+		var id2 cid.ID
 
-		require.NoError(t, id2.Parse(id.String()))
+		require.NoError(t, id2.DecodeString(id.String()))
 		require.Equal(t, id, id2)
 	})
 
-	t.Run("nil", func(t *testing.T) {
+	t.Run("zero", func(t *testing.T) {
-		id := cid.New()
+		var id cid.ID
 
-		require.Empty(t, id.String())
+		require.Equal(t, emptyID, id.EncodeToString())
-	})
-}
-
-func TestContainerIDEncoding(t *testing.T) {
-	id := cidtest.ID()
-
-	t.Run("binary", func(t *testing.T) {
-		data, err := id.Marshal()
-		require.NoError(t, err)
-
-		id2 := cid.New()
-		require.NoError(t, id2.Unmarshal(data))
-
-		require.Equal(t, id, id2)
-	})
-
-	t.Run("json", func(t *testing.T) {
-		data, err := id.MarshalJSON()
-		require.NoError(t, err)
-
-		a2 := cid.New()
-		require.NoError(t, a2.UnmarshalJSON(data))
-
-		require.Equal(t, id, a2)
 	})
 }
 
 func TestNewFromV2(t *testing.T) {
-	t.Run("from nil", func(t *testing.T) {
+	t.Run("from zero", func(t *testing.T) {
-		var x *refs.ContainerID
+		var (
+			x  cid.ID
+			v2 refs.ContainerID
+		)
 
-		require.Nil(t, cid.NewFromV2(x))
+		require.Error(t, x.ReadFromV2(v2))
+	})
+}
+
+func TestID_Encode(t *testing.T) {
+	var id cid.ID
+
+	t.Run("panic", func(t *testing.T) {
+		dst := make([]byte, sha256.Size-1)
+
+		require.Panics(t, func() {
+			id.Encode(dst)
+		})
+	})
+
+	t.Run("correct", func(t *testing.T) {
+		dst := make([]byte, sha256.Size)
+
+		require.NotPanics(t, func() {
+			id.Encode(dst)
+		})
+		require.Equal(t, emptyID, id.EncodeToString())
 	})
 }

container/id/test/doc.go

@@ -0,0 +1,13 @@
+/*
+Package cidtest provides functions for convenient testing of cid package API.
+
+Note that importing the package into source files is highly discouraged.
+
+Random instance generation functions can be useful when testing expects any value, e.g.:
+	import cidtest "github.com/nspcc-dev/neofs-sdk-go/container/id/test"
+
+	cid := cidtest.ID()
+	// test the value
+
+*/
+package cidtest

container/id/test/id.go

@@ -8,7 +8,7 @@ import (
 )
 
 // ID returns random cid.ID.
-func ID() *cid.ID {
+func ID() cid.ID {
 	checksum := [sha256.Size]byte{}
 
 	rand.Read(checksum[:])
@@ -18,8 +18,8 @@ func ID() *cid.ID {
 
 // IDWithChecksum returns cid.ID initialized
 // with specified checksum.
-func IDWithChecksum(cs [sha256.Size]byte) *cid.ID {
+func IDWithChecksum(cs [sha256.Size]byte) cid.ID {
-	id := cid.New()
+	var id cid.ID
 	id.SetSHA256(cs)
 
 	return id

eacl/record.go

@@ -112,12 +112,12 @@ func (r *Record) AddObjectVersionFilter(m Match, v *version.Version) {
 }
 
 // AddObjectIDFilter adds filter by object ID.
-func (r *Record) AddObjectIDFilter(m Match, id *oid.ID) {
+func (r *Record) AddObjectIDFilter(m Match, id oid.ID) {
 	r.addObjectReservedFilter(m, fKeyObjID, id)
 }
 
 // AddObjectContainerIDFilter adds filter by object container ID.
-func (r *Record) AddObjectContainerIDFilter(m Match, id *cid.ID) {
+func (r *Record) AddObjectContainerIDFilter(m Match, id cid.ID) {
 	r.addObjectReservedFilter(m, fKeyObjContainerID, id)
 }
 

eacl/table.go

@@ -16,19 +16,19 @@ import (
 // Table is compatible with v2 acl.EACLTable message.
 type Table struct {
 	version version.Version
-	cid     *cid.ID
+	cid     cid.ID
 	token   *session.Token
 	sig     *signature.Signature
 	records []Record
 }
 
 // CID returns identifier of the container that should use given access control rules.
-func (t Table) CID() *cid.ID {
+func (t Table) CID() cid.ID {
 	return t.cid
 }
 
 // SetCID sets identifier of the container that should use given access control rules.
-func (t *Table) SetCID(cid *cid.ID) {
+func (t *Table) SetCID(cid cid.ID) {
 	t.cid = cid
 }
 
@@ -85,9 +85,11 @@ func (t *Table) ToV2() *v2acl.Table {
 	}
 
 	v2 := new(v2acl.Table)
+	var cidV2 refs.ContainerID
 
-	if t.cid != nil {
+	if !t.cid.Empty() {
-		v2.SetContainerID(t.cid.ToV2())
+		t.cid.WriteToV2(&cidV2)
+		v2.SetContainerID(&cidV2)
 	}
 
 	if t.records != nil {
@@ -124,7 +126,7 @@ func NewTable() *Table {
 // CreateTable creates, initializes with parameters and returns Table instance.
 func CreateTable(cid cid.ID) *Table {
 	t := NewTable()
-	t.SetCID(&cid)
+	t.SetCID(cid)
 
 	return t
 }
@@ -148,8 +150,8 @@ func NewTableFromV2(table *v2acl.Table) *Table {
 
 	// set container id
 	if id := table.GetContainerID(); id != nil {
-		if t.cid == nil {
+		if t.cid.Empty() {
-			t.cid = new(cid.ID)
+			t.cid = cid.ID{}
 		}
 
 		var h [sha256.Size]byte
@@ -205,7 +207,7 @@ func (t *Table) UnmarshalJSON(data []byte) error {
 
 // EqualTables compares Table with each other.
 func EqualTables(t1, t2 Table) bool {
-	if !t1.CID().Equal(t2.CID()) ||
+	if !t1.CID().Equals(t2.CID()) ||
 		!t1.Version().Equal(t2.Version()) {
 		return false
 	}

eacl/table_test.go

@@ -45,7 +45,7 @@ func TestTable(t *testing.T) {
 	t.Run("create table", func(t *testing.T) {
 		id := cidtest.ID()
 
-		table := eacl.CreateTable(*id)
+		table := eacl.CreateTable(id)
 		require.Equal(t, id, table.CID())
 		require.Equal(t, version.Current(), table.Version())
 	})
@@ -124,7 +124,7 @@ func TestTable_ToV2(t *testing.T) {
 		// check initial values
 		require.Equal(t, version.Current(), table.Version())
 		require.Nil(t, table.Records())
-		require.Nil(t, table.CID())
+		require.True(t, table.CID().Empty())
 		require.Nil(t, table.SessionToken())
 		require.Nil(t, table.Signature())
 

ns/dns.go

@@ -16,20 +16,20 @@ type DNS struct{}
 // Otherwise, returns an error.
 //
 // See also net.LookupTXT.
-func (x *DNS) ResolveContainerName(name string) (*cid.ID, error) {
+func (x *DNS) ResolveContainerName(name string) (id cid.ID, err error) {
 	records, err := net.LookupTXT(name)
 	if err != nil {
-		return nil, err
+		return
 	}
 
-	var id cid.ID
-
 	for i := range records {
-		err = id.Parse(records[i])
+		err = id.DecodeString(records[i])
 		if err == nil {
-			return &id, nil
+			return
 		}
 	}
 
-	return nil, errNotFound
+	err = errNotFound
+
+	return
 }

ns/nns.go

@@ -114,7 +114,7 @@ func (n *NNS) Dial(address string) error {
 // ResolveContainerName MUST NOT be called before successful Dial.
 //
 // See also https://docs.neo.org/docs/en-us/reference/nns.html.
-func (n *NNS) ResolveContainerName(name string) (*cid.ID, error) {
+func (n *NNS) ResolveContainerName(name string) (cid.ID, error) {
 	res, err := n.neoClient.call(n.nnsContract, "resolve", []smartcontract.Parameter{
 		{
 			Type:  smartcontract.StringType,
@@ -126,25 +126,25 @@ func (n *NNS) ResolveContainerName(name string) (*cid.ID, error) {
 		},
 	})
 	if err != nil {
-		return nil, fmt.Errorf("invoke NNS contract: %w", err)
+		return cid.ID{}, fmt.Errorf("invoke NNS contract: %w", err)
 	}
 
 	if res.State != vm.HaltState.String() {
-		return nil, fmt.Errorf("NNS contract fault exception: %s", res.FaultException)
+		return cid.ID{}, fmt.Errorf("NNS contract fault exception: %s", res.FaultException)
 	} else if len(res.Stack) == 0 {
-		return nil, errors.New("empty stack in invocation result")
+		return cid.ID{}, errors.New("empty stack in invocation result")
 	}
 
 	itemArr, err := res.Stack[len(res.Stack)-1].Convert(stackitem.ArrayT) // top stack element is last in the array
 	if err != nil {
-		return nil, fmt.Errorf("convert stack item to %s", stackitem.ArrayT)
+		return cid.ID{}, fmt.Errorf("convert stack item to %s", stackitem.ArrayT)
 	}
 
 	if _, ok := itemArr.(stackitem.Null); !ok {
 		arr, ok := itemArr.Value().([]stackitem.Item)
 		if !ok {
 			// unexpected for types from stackitem package
-			return nil, errors.New("invalid cast to stack item slice")
+			return cid.ID{}, errors.New("invalid cast to stack item slice")
 		}
 
 		var id cid.ID
@@ -152,15 +152,15 @@ func (n *NNS) ResolveContainerName(name string) (*cid.ID, error) {
 		for i := range arr {
 			bs, err := arr[i].TryBytes()
 			if err != nil {
-				return nil, fmt.Errorf("convert array item to byte slice: %w", err)
+				return cid.ID{}, fmt.Errorf("convert array item to byte slice: %w", err)
 			}
 
-			err = id.Parse(string(bs))
+			err = id.DecodeString(string(bs))
 			if err == nil {
-				return &id, nil
+				return id, nil
 			}
 		}
 	}
 
-	return nil, errNotFound
+	return cid.ID{}, errNotFound
 }

object/address/address.go

@@ -45,41 +45,61 @@ func (a *Address) ToV2() *refs.Address {
 }
 
 // ContainerID returns container identifier.
-func (a *Address) ContainerID() *cid.ID {
+func (a *Address) ContainerID() (v cid.ID) {
-	return cid.NewFromV2(
+	var cID cid.ID
-		(*refs.Address)(a).GetContainerID())
+	v2 := (*refs.Address)(a)
+
+	cidV2 := v2.GetContainerID()
+	if cidV2 != nil {
+		_ = cID.ReadFromV2(*cidV2)
+	}
+
+	return cID
 }
 
 // SetContainerID sets container identifier.
-func (a *Address) SetContainerID(id *cid.ID) {
+func (a *Address) SetContainerID(id cid.ID) {
-	(*refs.Address)(a).SetContainerID(id.ToV2())
+	var cidV2 refs.ContainerID
+	id.WriteToV2(&cidV2)
+
+	(*refs.Address)(a).SetContainerID(&cidV2)
 }
 
 // ObjectID returns object identifier.
-func (a *Address) ObjectID() *oid.ID {
+func (a *Address) ObjectID() (v oid.ID) {
-	return oid.NewIDFromV2(
+	var id oid.ID
-		(*refs.Address)(a).GetObjectID())
+	v2 := (*refs.Address)(a)
+
+	oidV2 := v2.GetObjectID()
+	if oidV2 != nil {
+		_ = id.ReadFromV2(*oidV2)
+	}
+
+	return id
 }
 
 // SetObjectID sets object identifier.
-func (a *Address) SetObjectID(id *oid.ID) {
+func (a *Address) SetObjectID(id oid.ID) {
-	(*refs.Address)(a).SetObjectID(id.ToV2())
+	var oidV2 refs.ObjectID
+	id.WriteToV2(&oidV2)
+
+	(*refs.Address)(a).SetObjectID(&oidV2)
 }
 
 // Parse converts base58 string representation into Address.
 func (a *Address) Parse(s string) error {
 	var (
 		err   error
-		oid   = oid.NewID()
+		oid   oid.ID
-		id    = cid.New()
+		id    cid.ID
 		parts = strings.Split(s, addressSeparator)
 	)
 
 	if len(parts) != addressParts {
 		return errInvalidAddressString
-	} else if err = id.Parse(parts[0]); err != nil {
+	} else if err = id.DecodeString(parts[0]); err != nil {
 		return err
-	} else if err = oid.Parse(parts[1]); err != nil {
+	} else if err = oid.DecodeString(parts[1]); err != nil {
 		return err
 	}
 

object/address/address_test.go

@@ -107,8 +107,8 @@ func TestNewAddress(t *testing.T) {
 		a := NewAddress()
 
 		// check initial values
-		require.Nil(t, a.ContainerID())
+		require.True(t, a.ContainerID().Empty())
-		require.Nil(t, a.ObjectID())
+		require.True(t, a.ObjectID().Empty())
 
 		// convert to v2 message
 		aV2 := a.ToV2()

object/fmt.go

@@ -7,10 +7,10 @@ import (
 	"errors"
 	"fmt"
 
+	"github.com/nspcc-dev/neofs-api-go/v2/refs"
 	signatureV2 "github.com/nspcc-dev/neofs-api-go/v2/signature"
 	"github.com/nspcc-dev/neofs-sdk-go/checksum"
 	oid "github.com/nspcc-dev/neofs-sdk-go/object/id"
-	"github.com/nspcc-dev/neofs-sdk-go/signature"
 	sigutil "github.com/nspcc-dev/neofs-sdk-go/util/signature"
 )
 
@@ -55,13 +55,13 @@ func VerifyPayloadChecksum(obj *Object) error {
 }
 
 // CalculateID calculates identifier for the object.
-func CalculateID(obj *Object) (*oid.ID, error) {
+func CalculateID(obj *Object) (oid.ID, error) {
 	data, err := obj.ToV2().GetHeader().StableMarshal(nil)
 	if err != nil {
-		return nil, err
+		return oid.ID{}, err
 	}
 
-	id := oid.NewID()
+	var id oid.ID
 	id.SetSHA256(sha256.Sum256(data))
 
 	return id, nil
@@ -88,43 +88,45 @@ func VerifyID(obj *Object) error {
 		return err
 	}
 
-	if !id.Equal(obj.ID()) {
+	if !id.Equals(obj.ID()) {
 		return errIncorrectID
 	}
 
 	return nil
 }
 
-func CalculateIDSignature(key *ecdsa.PrivateKey, id *oid.ID) (*signature.Signature, error) {
+// CalculateAndSetSignature signs id with provided key and sets that signature to
-	return sigutil.SignData(
+// the object.
-		key,
+func CalculateAndSetSignature(key ecdsa.PrivateKey, obj *Object) error {
-		signatureV2.StableMarshalerWrapper{
+	sig, err := obj.ID().CalculateIDSignature(key)
-			SM: id.ToV2(),
-		})
-}
-
-func CalculateAndSetSignature(key *ecdsa.PrivateKey, obj *Object) error {
-	sig, err := CalculateIDSignature(key, obj.ID())
 	if err != nil {
 		return err
 	}
 
-	obj.SetSignature(sig)
+	obj.SetSignature(&sig)
 
 	return nil
 }
 
-func VerifyIDSignature(obj *Object) error {
+// VerifyIDSignature verifies object ID signature.
-	return sigutil.VerifyData(
+func (o *Object) VerifyIDSignature() bool {
+	var idV2 refs.ObjectID
+	o.ID().WriteToV2(&idV2)
+
+	sig := o.Signature()
+
+	err := sigutil.VerifyData(
 		signatureV2.StableMarshalerWrapper{
-			SM: obj.ID().ToV2(),
+			SM: &idV2,
 		},
-		obj.Signature(),
+		sig,
 	)
+
+	return err == nil
 }
 
 // SetIDWithSignature sets object identifier and signature.
-func SetIDWithSignature(key *ecdsa.PrivateKey, obj *Object) error {
+func SetIDWithSignature(key ecdsa.PrivateKey, obj *Object) error {
 	if err := CalculateAndSetID(obj); err != nil {
 		return fmt.Errorf("could not set identifier: %w", err)
 	}
@@ -137,7 +139,7 @@ func SetIDWithSignature(key *ecdsa.PrivateKey, obj *Object) error {
 }
 
 // SetVerificationFields calculates and sets all verification fields of the object.
-func SetVerificationFields(key *ecdsa.PrivateKey, obj *Object) error {
+func SetVerificationFields(key ecdsa.PrivateKey, obj *Object) error {
 	CalculateAndSetPayloadChecksum(obj)
 
 	return SetIDWithSignature(key, obj)
@@ -156,10 +158,12 @@ func CheckVerificationFields(obj *Object) error {
 	return nil
 }
 
+var errInvalidSignature = errors.New("invalid signature")
+
 // CheckHeaderVerificationFields checks all verification fields except payload.
 func CheckHeaderVerificationFields(obj *Object) error {
-	if err := VerifyIDSignature(obj); err != nil {
+	if !obj.VerifyIDSignature() {
-		return fmt.Errorf("invalid signature: %w", err)
+		return errInvalidSignature
 	}
 
 	if err := VerifyID(obj); err != nil {

object/fmt_test.go

@@ -19,7 +19,7 @@ func TestVerificationFields(t *testing.T) {
 
 	p, err := keys.NewPrivateKey()
 	require.NoError(t, err)
-	require.NoError(t, SetVerificationFields(&p.PrivateKey, obj))
+	require.NoError(t, SetVerificationFields(p.PrivateKey, obj))
 
 	require.NoError(t, CheckVerificationFields(obj))
 
@@ -45,10 +45,10 @@ func TestVerificationFields(t *testing.T) {
 		},
 		{
 			corrupt: func() {
-				obj.ID().ToV2().GetValue()[0]++
+				obj.ToV2().GetObjectID().GetValue()[0]++
 			},
 			restore: func() {
-				obj.ID().ToV2().GetValue()[0]--
+				obj.ToV2().GetObjectID().GetValue()[0]--
 			},
 		},
 		{

object/id/doc.go

@@ -0,0 +1,8 @@
+/*
+Package oid provides primitives to work with object identification in NeoFS.
+
+Using package types in an application is recommended to potentially work with
+different protocol versions with which these types are compatible.
+
+*/
+package oid

object/id/id.go

@@ -1,92 +1,177 @@
 package oid
 
 import (
-	"bytes"
+	"crypto/ecdsa"
 	"crypto/sha256"
-	"errors"
 	"fmt"
 
 	"github.com/mr-tron/base58"
 	"github.com/nspcc-dev/neofs-api-go/v2/refs"
+	signatureV2 "github.com/nspcc-dev/neofs-api-go/v2/signature"
+	"github.com/nspcc-dev/neofs-sdk-go/signature"
+	sigutil "github.com/nspcc-dev/neofs-sdk-go/util/signature"
 )
 
-// ID represents v2-compatible object identifier.
+// ID represents NeoFS object identifier in a container.
-type ID refs.ObjectID
-
-var errInvalidIDString = errors.New("incorrect format of the string object ID")
-
-// NewIDFromV2 wraps v2 ObjectID message to ID.
 //
-// Nil refs.ObjectID converts to nil.
+// ID is mutually compatible with github.com/nspcc-dev/neofs-api-go/v2/refs.ObjectID
-func NewIDFromV2(idV2 *refs.ObjectID) *ID {
+// message. See ReadFromV2 / WriteToV2 methods.
-	return (*ID)(idV2)
-}
-
-// NewID creates and initializes blank ID.
 //
-// Works similar as NewIDFromV2(new(ObjectID)).
+// Instances can be created using built-in var declaration.
 //
-// Defaults:
+// Note that direct typecast is not safe and may result in loss of compatibility:
-// 	- value: nil.
+// 	_ = ObjectID([32]byte{}) // not recommended
-func NewID() *ID {
+type ID [sha256.Size]byte
-	return NewIDFromV2(new(refs.ObjectID))
-}
 
-// SetSHA256 sets object identifier value to SHA256 checksum.
+// ReadFromV2 reads ID from the refs.ObjectID message. Returns an error if
-func (id *ID) SetSHA256(v [sha256.Size]byte) {
+// the message is malformed according to the NeoFS API V2 protocol.
-	(*refs.ObjectID)(id).SetValue(v[:])
-}
-
-// Equal returns true if identifiers are identical.
-func (id *ID) Equal(id2 *ID) bool {
-	return bytes.Equal(
-		(*refs.ObjectID)(id).GetValue(),
-		(*refs.ObjectID)(id2).GetValue(),
-	)
-}
-
-// ToV2 converts ID to v2 ObjectID message.
 //
-// Nil ID converts to nil.
+// See also WriteToV2.
-func (id *ID) ToV2() *refs.ObjectID {
+func (id *ID) ReadFromV2(m refs.ObjectID) error {
-	return (*refs.ObjectID)(id)
+	return id.Decode(m.GetValue())
 }
 
-// Parse converts base58 string representation into ID.
+// WriteToV2 writes ID to the refs.ObjectID message.
-func (id *ID) Parse(s string) error {
+// The message must not be nil.
-	data, err := base58.Decode(s)
+//
-	if err != nil {
+// See also ReadFromV2.
-		return fmt.Errorf("could not parse object.ID from string: %w", err)
+func (id ID) WriteToV2(m *refs.ObjectID) {
-	} else if len(data) != sha256.Size {
+	m.SetValue(id[:])
-		return errInvalidIDString
 }
 
-	(*refs.ObjectID)(id).SetValue(data)
+// Encode encodes ID into 32 bytes of dst. Panics if
+// dst length is less than 32.
+//
+// Zero ID is all zeros.
+//
+// See also Decode.
+func (id ID) Encode(dst []byte) {
+	if l := len(dst); l < sha256.Size {
+		panic(fmt.Sprintf("destination length is less than %d bytes: %d", sha256.Size, l))
+	}
+
+	copy(dst, id[:])
+}
+
+// Decode decodes src bytes into ID.
+//
+// Decode expects that src has 32 bytes length. If the input is malformed,
+// Decode returns an error describing format violation. In this case ID
+// remains unchanged.
+//
+// Decode doesn't mutate src.
+//
+// See also Encode.
+func (id *ID) Decode(src []byte) error {
+	if len(src) != 32 {
+		return fmt.Errorf("invalid length %d", len(src))
+	}
+
+	copy(id[:], src)
 
 	return nil
 }
 
-// String returns base58 string representation of ID.
+// SetSHA256 sets object identifier value to SHA256 checksum.
-func (id *ID) String() string {
+func (id *ID) SetSHA256(v [sha256.Size]byte) {
-	return base58.Encode((*refs.ObjectID)(id).GetValue())
+	copy(id[:], v[:])
+}
+
+// Equals defines a comparison relation between two ID instances.
+//
+// Note that comparison using '==' operator is not recommended since it MAY result
+// in loss of compatibility.
+func (id ID) Equals(id2 ID) bool {
+	return id == id2
+}
+
+// EncodeToString encodes ID into NeoFS API protocol string.
+//
+// Zero ID is base58 encoding of 32 zeros.
+//
+// See also DecodeString.
+func (id ID) EncodeToString() string {
+	return base58.Encode(id[:])
+}
+
+// DecodeString decodes string into ID according to NeoFS API protocol. Returns
+// an error if s is malformed.
+//
+// See also DecodeString.
+func (id *ID) DecodeString(s string) error {
+	data, err := base58.Decode(s)
+	if err != nil {
+		return fmt.Errorf("decode base58: %w", err)
+	}
+
+	return id.Decode(data)
+}
+
+// String implements fmt.Stringer.
+//
+// String is designed to be human-readable, and its format MAY differ between
+// SDK versions. String MAY return same result as EncodeToString. String MUST NOT
+// be used to encode ID into NeoFS protocol string.
+func (id ID) String() string {
+	return id.EncodeToString()
+}
+
+// CalculateIDSignature signs object id with provided key.
+func (id ID) CalculateIDSignature(key ecdsa.PrivateKey) (signature.Signature, error) {
+	var idV2 refs.ObjectID
+	id.WriteToV2(&idV2)
+
+	sign, err := sigutil.SignData(&key,
+		signatureV2.StableMarshalerWrapper{
+			SM: &idV2,
+		},
+	)
+
+	return *sign, err
+}
+
+// Empty returns true if it is called on
+// zero object ID.
+func (id ID) Empty() bool {
+	return id == ID{}
 }
 
 // Marshal marshals ID into a protobuf binary form.
-func (id *ID) Marshal() ([]byte, error) {
+func (id ID) Marshal() ([]byte, error) {
-	return (*refs.ObjectID)(id).StableMarshal(nil)
+	var v2 refs.ObjectID
+	v2.SetValue(id[:])
+
+	return v2.StableMarshal(nil)
 }
 
 // Unmarshal unmarshals protobuf binary representation of ID.
 func (id *ID) Unmarshal(data []byte) error {
-	return (*refs.ObjectID)(id).Unmarshal(data)
+	var v2 refs.ObjectID
+	if err := v2.Unmarshal(data); err != nil {
+		return err
+	}
+
+	copy(id[:], v2.GetValue())
+
+	return nil
 }
 
 // MarshalJSON encodes ID to protobuf JSON format.
-func (id *ID) MarshalJSON() ([]byte, error) {
+func (id ID) MarshalJSON() ([]byte, error) {
-	return (*refs.ObjectID)(id).MarshalJSON()
+	var v2 refs.ObjectID
+	v2.SetValue(id[:])
+
+	return v2.MarshalJSON()
 }
 
 // UnmarshalJSON decodes ID from protobuf JSON format.
 func (id *ID) UnmarshalJSON(data []byte) error {
-	return (*refs.ObjectID)(id).UnmarshalJSON(data)
+	var v2 refs.ObjectID
+	if err := v2.UnmarshalJSON(data); err != nil {
+		return err
+	}
+
+	copy(id[:], v2.GetValue())
+
+	return nil
 }

object/id/id_test.go

@@ -11,8 +11,10 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-func randID(t *testing.T) *ID {
+const emptyID = "11111111111111111111111111111111"
-	id := NewID()
+
+func randID(t *testing.T) ID {
+	var id ID
 	id.SetSHA256(randSHA256Checksum(t))
 
 	return id
@@ -26,7 +28,7 @@ func randSHA256Checksum(t *testing.T) (cs [sha256.Size]byte) {
 }
 
 func TestIDV2(t *testing.T) {
-	id := NewID()
+	var id ID
 
 	checksum := [sha256.Size]byte{}
 
@@ -35,7 +37,8 @@ func TestIDV2(t *testing.T) {
 
 	id.SetSHA256(checksum)
 
-	idV2 := id.ToV2()
+	var idV2 refs.ObjectID
+	id.WriteToV2(&idV2)
 
 	require.Equal(t, checksum[:], idV2.GetValue())
 }
@@ -43,17 +46,17 @@ func TestIDV2(t *testing.T) {
 func TestID_Equal(t *testing.T) {
 	cs := randSHA256Checksum(t)
 
-	id1 := NewID()
+	var id1 ID
 	id1.SetSHA256(cs)
 
-	id2 := NewID()
+	var id2 ID
 	id2.SetSHA256(cs)
 
-	id3 := NewID()
+	var id3 ID
 	id3.SetSHA256(randSHA256Checksum(t))
 
-	require.True(t, id1.Equal(id2))
+	require.True(t, id1.Equals(id2))
-	require.False(t, id1.Equal(id3))
+	require.False(t, id1.Equals(id3))
 }
 
 func TestID_Parse(t *testing.T) {
@@ -62,10 +65,14 @@ func TestID_Parse(t *testing.T) {
 			t.Run(strconv.Itoa(i), func(t *testing.T) {
 				cs := randSHA256Checksum(t)
 				str := base58.Encode(cs[:])
-				oid := NewID()
+				var oid ID
 
-				require.NoError(t, oid.Parse(str))
+				require.NoError(t, oid.DecodeString(str))
-				require.Equal(t, cs[:], oid.ToV2().GetValue())
+
+				var oidV2 refs.ObjectID
+				oid.WriteToV2(&oidV2)
+
+				require.Equal(t, cs[:], oidV2.GetValue())
 			})
 		}
 	})
@@ -76,18 +83,18 @@ func TestID_Parse(t *testing.T) {
 			t.Run(strconv.Itoa(j), func(t *testing.T) {
 				cs := []byte{1, 2, 3, 4, 5, byte(j)}
 				str := base58.Encode(cs)
-				oid := NewID()
+				var oid ID
 
-				require.Error(t, oid.Parse(str))
+				require.Error(t, oid.DecodeString(str))
 			})
 		}
 	})
 }
 
 func TestID_String(t *testing.T) {
-	t.Run("nil", func(t *testing.T) {
+	t.Run("zero", func(t *testing.T) {
-		id := NewID()
+		var id ID
-		require.Empty(t, id.String())
+		require.Equal(t, emptyID, id.EncodeToString())
 	})
 
 	t.Run("should be equal", func(t *testing.T) {
@@ -95,9 +102,9 @@ func TestID_String(t *testing.T) {
 			t.Run(strconv.Itoa(i), func(t *testing.T) {
 				cs := randSHA256Checksum(t)
 				str := base58.Encode(cs[:])
-				oid := NewID()
+				var oid ID
 
-				require.NoError(t, oid.Parse(str))
+				require.NoError(t, oid.DecodeString(str))
 				require.Equal(t, str, oid.String())
 			})
 		}
@@ -111,7 +118,7 @@ func TestObjectIDEncoding(t *testing.T) {
 		data, err := id.Marshal()
 		require.NoError(t, err)
 
-		id2 := NewID()
+		var id2 ID
 		require.NoError(t, id2.Unmarshal(data))
 
 		require.Equal(t, id, id2)
@@ -121,36 +128,55 @@ func TestObjectIDEncoding(t *testing.T) {
 		data, err := id.MarshalJSON()
 		require.NoError(t, err)
 
-		a2 := NewID()
+		var id2 ID
-		require.NoError(t, a2.UnmarshalJSON(data))
+		require.NoError(t, id2.UnmarshalJSON(data))
 
-		require.Equal(t, id, a2)
+		require.Equal(t, id, id2)
 	})
 }
 
 func TestNewIDFromV2(t *testing.T) {
-	t.Run("from nil", func(t *testing.T) {
+	t.Run("from zero", func(t *testing.T) {
-		var x *refs.ObjectID
+		var (
+			x  ID
+			v2 refs.ObjectID
+		)
 
-		require.Nil(t, NewIDFromV2(x))
+		require.Error(t, x.ReadFromV2(v2))
 	})
 }
 
 func TestID_ToV2(t *testing.T) {
-	t.Run("nil", func(t *testing.T) {
+	t.Run("zero to v2", func(t *testing.T) {
-		var x *ID
+		var (
+			x  ID
+			v2 refs.ObjectID
+		)
 
-		require.Nil(t, x.ToV2())
+		x.WriteToV2(&v2)
+
+		require.Equal(t, sha256.Size, len(v2.GetValue()))
+		require.Equal(t, emptyID, base58.Encode(v2.GetValue()))
 	})
 }
 
-func TestNewID(t *testing.T) {
+func TestID_Encode(t *testing.T) {
-	t.Run("default values", func(t *testing.T) {
+	var id ID
-		id := NewID()
 
-		// convert to v2 message
+	t.Run("panic", func(t *testing.T) {
-		idV2 := id.ToV2()
+		dst := make([]byte, sha256.Size-1)
 
-		require.Nil(t, idV2.GetValue())
+		require.Panics(t, func() {
+			id.Encode(dst)
+		})
+	})
+
+	t.Run("correct", func(t *testing.T) {
+		dst := make([]byte, sha256.Size)
+
+		require.NotPanics(t, func() {
+			id.Encode(dst)
+		})
+		require.Equal(t, emptyID, id.EncodeToString())
 	})
 }

object/id/test/doc.go

@@ -0,0 +1,13 @@
+/*
+Package oidtest provides functions for convenient testing of oid package API.
+
+Note that importing the package into source files is highly discouraged.
+
+Random instance generation functions can be useful when testing expects any value, e.g.:
+	import oidtest "github.com/nspcc-dev/neofs-sdk-go/object/id/test"
+
+	dec := oidtest.ID()
+	// test the value
+
+*/
+package oidtest

object/id/test/generate.go

@@ -1,4 +1,4 @@
-package test
+package oidtest
 
 import (
 	"crypto/sha256"
@@ -8,7 +8,7 @@ import (
 )
 
 // ID returns random object.ID.
-func ID() *oid.ID {
+func ID() oid.ID {
 	checksum := [sha256.Size]byte{}
 
 	rand.Read(checksum[:])
@@ -18,8 +18,8 @@ func ID() *oid.ID {
 
 // idWithChecksum returns object.ID initialized
 // with specified checksum.
-func idWithChecksum(cs [sha256.Size]byte) *oid.ID {
+func idWithChecksum(cs [sha256.Size]byte) oid.ID {
-	id := oid.NewID()
+	var id oid.ID
 	id.SetSHA256(cs)
 
 	return id

object/lock.go

@@ -41,8 +41,8 @@ func (x Lock) NumberOfMembers() int {
 func (x Lock) ReadMembers(buf []oid.ID) {
 	var i int
 
-	(*v2object.Lock)(&x).IterateMembers(func(id refs.ObjectID) {
+	(*v2object.Lock)(&x).IterateMembers(func(idV2 refs.ObjectID) {
-		buf[i] = *oid.NewIDFromV2(&id) // need smth better
+		_ = buf[i].ReadFromV2(idV2)
 		i++
 	})
 }
@@ -55,7 +55,7 @@ func (x *Lock) WriteMembers(ids []oid.ID) {
 		members = make([]refs.ObjectID, len(ids))
 
 		for i := range ids {
-			members[i] = *ids[i].ToV2() // need smth better
+			ids[i].WriteToV2(&members[i])
 		}
 	}
 

object/object.go

@@ -34,7 +34,7 @@ type RequiredFields struct {
 // InitCreation initializes the object instance with minimum set of required fields.
 // Object is expected (but not required) to be blank. Object must not be nil.
 func InitCreation(dst *Object, rf RequiredFields) {
-	dst.SetContainerID(&rf.Container)
+	dst.SetContainerID(rf.Container)
 	dst.SetOwnerID(&rf.Owner)
 }
 
@@ -86,17 +86,24 @@ func (o *Object) setSplitFields(setter func(*object.SplitHeader)) {
 }
 
 // ID returns object identifier.
-func (o *Object) ID() *oid.ID {
+func (o *Object) ID() oid.ID {
-	return oid.NewIDFromV2(
+	var v oid.ID
-		(*object.Object)(o).
+
-			GetObjectID(),
+	v2 := (*object.Object)(o)
-	)
+	if id := v2.GetObjectID(); id != nil {
+		_ = v.ReadFromV2(*v2.GetObjectID())
+	}
+
+	return v
 }
 
 // SetID sets object identifier.
-func (o *Object) SetID(v *oid.ID) {
+func (o *Object) SetID(v oid.ID) {
+	var v2 refs.ObjectID
+	v.WriteToV2(&v2)
+
 	(*object.Object)(o).
-		SetObjectID(v.ToV2())
+		SetObjectID(&v2)
 }
 
 // Signature returns signature of the object identifier.
@@ -154,18 +161,25 @@ func (o *Object) SetPayloadSize(v uint64) {
 }
 
 // ContainerID returns identifier of the related container.
-func (o *Object) ContainerID() *cid.ID {
+func (o *Object) ContainerID() cid.ID {
-	return cid.NewFromV2(
+	var cID cid.ID
-		(*object.Object)(o).
+	v2 := (*object.Object)(o)
-			GetHeader().
+
-			GetContainerID(),
+	cidV2 := v2.GetHeader().GetContainerID()
-	)
+	if cidV2 != nil {
+		_ = cID.ReadFromV2(*cidV2)
+	}
+
+	return cID
 }
 
 // SetContainerID sets identifier of the related container.
-func (o *Object) SetContainerID(v *cid.ID) {
+func (o *Object) SetContainerID(v cid.ID) {
+	var cidV2 refs.ContainerID
+	v.WriteToV2(&cidV2)
+
 	o.setHeaderField(func(h *object.Header) {
-		h.SetContainerID(v.ToV2())
+		h.SetContainerID(&cidV2)
 	})
 }
 
@@ -290,33 +304,41 @@ func (o *Object) SetAttributes(v ...Attribute) {
 }
 
 // PreviousID returns identifier of the previous sibling object.
-func (o *Object) PreviousID() *oid.ID {
+func (o *Object) PreviousID() oid.ID {
-	return oid.NewIDFromV2(
+	var v oid.ID
-		(*object.Object)(o).
+	v2 := (*object.Object)(o)
-			GetHeader().
+
-			GetSplit().
+	v2Prev := v2.GetHeader().GetSplit().GetPrevious()
-			GetPrevious(),
+	if v2Prev != nil {
-	)
+		_ = v.ReadFromV2(*v2Prev)
+	}
+
+	return v
 }
 
 // SetPreviousID sets identifier of the previous sibling object.
-func (o *Object) SetPreviousID(v *oid.ID) {
+func (o *Object) SetPreviousID(v oid.ID) {
+	var v2 refs.ObjectID
+	v.WriteToV2(&v2)
+
 	o.setSplitFields(func(split *object.SplitHeader) {
-		split.SetPrevious(v.ToV2())
+		split.SetPrevious(&v2)
 	})
 }
 
 // Children return list of the identifiers of the child objects.
 func (o *Object) Children() []oid.ID {
-	ids := (*object.Object)(o).
+	v2 := (*object.Object)(o)
-		GetHeader().
+	ids := v2.GetHeader().GetSplit().GetChildren()
-		GetSplit().
-		GetChildren()
 
-	res := make([]oid.ID, len(ids))
+	var (
+		id  oid.ID
+		res = make([]oid.ID, len(ids))
+	)
 
 	for i := range ids {
-		res[i] = *oid.NewIDFromV2(&ids[i])
+		_ = id.ReadFromV2(ids[i])
+		res[i] = id
 	}
 
 	return res
@@ -324,10 +346,14 @@ func (o *Object) Children() []oid.ID {
 
 // SetChildren sets list of the identifiers of the child objects.
 func (o *Object) SetChildren(v ...oid.ID) {
-	ids := make([]refs.ObjectID, len(v))
+	var (
+		v2  refs.ObjectID
+		ids = make([]refs.ObjectID, len(v))
+	)
 
 	for i := range v {
-		ids[i] = *v[i].ToV2()
+		v[i].WriteToV2(&v2)
+		ids[i] = v2
 	}
 
 	o.setSplitFields(func(split *object.SplitHeader) {
@@ -406,19 +432,25 @@ func (o *Object) SetSplitID(id *SplitID) {
 }
 
 // ParentID returns identifier of the parent object.
-func (o *Object) ParentID() *oid.ID {
+func (o *Object) ParentID() oid.ID {
-	return oid.NewIDFromV2(
+	var v oid.ID
-		(*object.Object)(o).
+	v2 := (*object.Object)(o)
-			GetHeader().
+
-			GetSplit().
+	v2Par := v2.GetHeader().GetSplit().GetParent()
-			GetParent(),
+	if v2Par != nil {
-	)
+		_ = v.ReadFromV2(*v2Par)
+	}
+
+	return v
 }
 
 // SetParentID sets identifier of the parent object.
-func (o *Object) SetParentID(v *oid.ID) {
+func (o *Object) SetParentID(v oid.ID) {
+	var v2 refs.ObjectID
+	v.WriteToV2(&v2)
+
 	o.setSplitFields(func(split *object.SplitHeader) {
-		split.SetParent(v.ToV2())
+		split.SetParent(&v2)
 	})
 }
 

object/object_test.go

@@ -11,7 +11,7 @@ import (
 
 func TestInitCreation(t *testing.T) {
 	var o object.Object
-	cnr := *cidtest.ID()
+	cnr := cidtest.ID()
 	own := *ownertest.ID()
 
 	object.InitCreation(&o, object.RequiredFields{
@@ -19,6 +19,6 @@ func TestInitCreation(t *testing.T) {
 		Owner:     own,
 	})
 
-	require.Equal(t, &cnr, o.ContainerID())
+	require.Equal(t, cnr, o.ContainerID())
 	require.Equal(t, &own, o.OwnerID())
 }

object/raw_test.go

@@ -16,8 +16,8 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-func randID(t *testing.T) *oid.ID {
+func randID(t *testing.T) oid.ID {
-	id := oid.NewID()
+	var id oid.ID
 	id.SetSHA256(randSHA256Checksum(t))
 
 	return id
@@ -177,9 +177,9 @@ func TestObject_SetChildren(t *testing.T) {
 	id1 := randID(t)
 	id2 := randID(t)
 
-	obj.SetChildren(*id1, *id2)
+	obj.SetChildren(id1, id2)
 
-	require.Equal(t, []oid.ID{*id1, *id2}, obj.Children())
+	require.Equal(t, []oid.ID{id1, id2}, obj.Children())
 }
 
 func TestObject_SetSplitID(t *testing.T) {
@@ -280,7 +280,7 @@ func TestObject_ResetRelations(t *testing.T) {
 
 	obj.ResetRelations()
 
-	require.Nil(t, obj.PreviousID())
+	require.True(t, obj.PreviousID().Empty())
 }
 
 func TestObject_HasParent(t *testing.T) {

object/search.go

@@ -220,7 +220,7 @@ func (f *SearchFilters) AddObjectVersionFilter(op SearchMatchType, v *version.Ve
 	f.addReservedFilter(op, fKeyVersion, v)
 }
 
-func (f *SearchFilters) AddObjectContainerIDFilter(m SearchMatchType, id *cid.ID) {
+func (f *SearchFilters) AddObjectContainerIDFilter(m SearchMatchType, id cid.ID) {
 	f.addReservedFilter(m, fKeyContainerID, id)
 }
 
@@ -261,12 +261,12 @@ func (f *SearchFilters) AddPhyFilter() {
 }
 
 // AddParentIDFilter adds filter by parent identifier.
-func (f *SearchFilters) AddParentIDFilter(m SearchMatchType, id *oid.ID) {
+func (f *SearchFilters) AddParentIDFilter(m SearchMatchType, id oid.ID) {
 	f.addReservedFilter(m, fKeyParent, id)
 }
 
 // AddObjectIDFilter adds filter by object identifier.
-func (f *SearchFilters) AddObjectIDFilter(m SearchMatchType, id *oid.ID) {
+func (f *SearchFilters) AddObjectIDFilter(m SearchMatchType, id oid.ID) {
 	f.addReservedFilter(m, fKeyObjectID, id)
 }
 

object/search_test.go

@@ -100,12 +100,12 @@ func TestSearchFilters_AddPhyFilter(t *testing.T) {
 	require.Equal(t, "", f.Value())
 }
 
-func testOID() *oid.ID {
+func testOID() oid.ID {
 	cs := [sha256.Size]byte{}
 
 	rand.Read(cs[:])
 
-	id := oid.NewID()
+	var id oid.ID
 	id.SetSHA256(cs)
 
 	return id

object/splitinfo.go

@@ -2,6 +2,7 @@ package object
 
 import (
 	"github.com/nspcc-dev/neofs-api-go/v2/object"
+	"github.com/nspcc-dev/neofs-api-go/v2/refs"
 	oid "github.com/nspcc-dev/neofs-sdk-go/object/id"
 )
 
@@ -40,22 +41,42 @@ func (s *SplitInfo) SetSplitID(v *SplitID) {
 	(*object.SplitInfo)(s).SetSplitID(v.ToV2())
 }
 
-func (s *SplitInfo) LastPart() *oid.ID {
+func (s SplitInfo) LastPart() oid.ID {
-	return oid.NewIDFromV2(
+	var id oid.ID
-		(*object.SplitInfo)(s).GetLastPart())
+	v2 := (object.SplitInfo)(s)
+
+	lpV2 := v2.GetLastPart()
+	if lpV2 != nil {
+		_ = id.ReadFromV2(*lpV2)
 	}
 
-func (s *SplitInfo) SetLastPart(v *oid.ID) {
+	return id
-	(*object.SplitInfo)(s).SetLastPart(v.ToV2())
 }
 
-func (s *SplitInfo) Link() *oid.ID {
+func (s *SplitInfo) SetLastPart(v oid.ID) {
-	return oid.NewIDFromV2(
+	var idV2 refs.ObjectID
-		(*object.SplitInfo)(s).GetLink())
+	v.WriteToV2(&idV2)
+
+	(*object.SplitInfo)(s).SetLastPart(&idV2)
 }
 
-func (s *SplitInfo) SetLink(v *oid.ID) {
+func (s SplitInfo) Link() oid.ID {
-	(*object.SplitInfo)(s).SetLink(v.ToV2())
+	var id oid.ID
+	v2 := (object.SplitInfo)(s)
+
+	linkV2 := v2.GetLink()
+	if linkV2 != nil {
+		_ = id.ReadFromV2(*linkV2)
+	}
+
+	return id
+}
+
+func (s *SplitInfo) SetLink(v oid.ID) {
+	var idV2 refs.ObjectID
+	v.WriteToV2(&idV2)
+
+	(*object.SplitInfo)(s).SetLink(&idV2)
 }
 
 func (s *SplitInfo) Marshal() ([]byte, error) {

object/splitinfo_test.go

@@ -45,11 +45,11 @@ func TestSplitInfo(t *testing.T) {
 	})
 }
 
-func generateID() *oid.ID {
+func generateID() oid.ID {
 	var buf [32]byte
 	_, _ = rand.Read(buf[:])
 
-	id := oid.NewID()
+	var id oid.ID
 	id.SetSHA256(buf)
 
 	return id
@@ -77,8 +77,8 @@ func TestNewSplitInfo(t *testing.T) {
 
 		// check initial values
 		require.Nil(t, si.SplitID())
-		require.Nil(t, si.LastPart())
+		require.True(t, si.LastPart().Empty())
-		require.Nil(t, si.Link())
+		require.True(t, si.Link().Empty())
 
 		// convert to v2 message
 		siV2 := si.ToV2()

object/test/generate.go

@@ -57,7 +57,7 @@ func generate(withParent bool) *object.Object {
 	x.SetCreationEpoch(222)
 	x.SetPreviousID(oidtest.ID())
 	x.SetParentID(oidtest.ID())
-	x.SetChildren(*oidtest.ID(), *oidtest.ID())
+	x.SetChildren(oidtest.ID(), oidtest.ID())
 	x.SetAttributes(*Attribute(), *Attribute())
 	x.SetSplitID(SplitID())
 	x.SetPayloadChecksum(checksumtest.Checksum())
@@ -88,7 +88,7 @@ func Tombstone() *object.Tombstone {
 
 	x.SetSplitID(SplitID())
 	x.SetExpirationEpoch(13)
-	x.SetMembers([]oid.ID{*oidtest.ID(), *oidtest.ID()})
+	x.SetMembers([]oid.ID{oidtest.ID(), oidtest.ID()})
 
 	return x
 }
@@ -117,7 +117,7 @@ func SearchFilters() object.SearchFilters {
 // Lock returns random object.Lock.
 func Lock() *object.Lock {
 	var l object.Lock
-	l.WriteMembers([]oid.ID{*oidtest.ID(), *oidtest.ID()})
+	l.WriteMembers([]oid.ID{oidtest.ID(), oidtest.ID()})
 
 	return &l
 }

object/tombstone.go

@@ -56,17 +56,21 @@ func (t *Tombstone) SetSplitID(v *SplitID) {
 
 // Members returns list of objects to be deleted.
 func (t *Tombstone) Members() []oid.ID {
-	msV2 := (*tombstone.Tombstone)(t).
+	v2 := (*tombstone.Tombstone)(t)
-		GetMembers()
+	msV2 := v2.GetMembers()
 
 	if msV2 == nil {
 		return nil
 	}
 
-	ms := make([]oid.ID, len(msV2))
+	var (
+		ms = make([]oid.ID, len(msV2))
+		id oid.ID
+	)
 
 	for i := range msV2 {
-		ms[i] = *oid.NewIDFromV2(&msV2[i])
+		_ = id.ReadFromV2(msV2[i])
+		ms[i] = id
 	}
 
 	return ms
@@ -86,8 +90,11 @@ func (t *Tombstone) SetMembers(v []oid.ID) {
 			ms = make([]refs.ObjectID, 0, ln)
 		}
 
+		var idV2 refs.ObjectID
+
 		for i := range v {
-			ms = append(ms, *v[i].ToV2())
+			v[i].WriteToV2(&idV2)
+			ms = append(ms, idV2)
 		}
 	}
 

object/tombstone_test.go

@@ -15,7 +15,9 @@ func generateIDList(sz int) []oid.ID {
 	cs := [sha256.Size]byte{}
 
 	for i := 0; i < sz; i++ {
-		res[i] = *oid.NewID()
+		var oID oid.ID
+
+		res[i] = oID
 		rand.Read(cs[:])
 		res[i].SetSHA256(cs)
 	}

session/container.go

@@ -1,6 +1,7 @@
 package session
 
 import (
+	"github.com/nspcc-dev/neofs-api-go/v2/refs"
 	"github.com/nspcc-dev/neofs-api-go/v2/session"
 	cid "github.com/nspcc-dev/neofs-sdk-go/container/id"
 )
@@ -43,8 +44,17 @@ func (x *ContainerContext) ToV2() *session.ContainerSessionContext {
 func (x *ContainerContext) ApplyTo(id *cid.ID) {
 	v2 := (*session.ContainerSessionContext)(x)
 
+	var cidV2 *refs.ContainerID
+
+	if id != nil {
+		var c refs.ContainerID
+		id.WriteToV2(&c)
+
+		cidV2 = &c
+	}
+
 	v2.SetWildcard(id == nil)
-	v2.SetContainerID(id.ToV2())
+	v2.SetContainerID(cidV2)
 }
 
 // ApplyToAllContainers is a helper function that conveniently
@@ -65,7 +75,15 @@ func (x *ContainerContext) Container() *cid.ID {
 		return nil
 	}
 
-	return cid.NewFromV2(v2.ContainerID())
+	cidV2 := v2.ContainerID()
+	if cidV2 == nil {
+		return nil
+	}
+
+	var cID cid.ID
+	_ = cID.ReadFromV2(*cidV2)
+
+	return &cID
 }
 
 func (x *ContainerContext) forVerb(v session.ContainerSessionVerb) {

session/container_test.go

@@ -39,9 +39,9 @@ func TestContainerContext_ApplyTo(t *testing.T) {
 	id := cidtest.ID()
 
 	t.Run("method", func(t *testing.T) {
-		c.ApplyTo(id)
+		c.ApplyTo(&id)
 
-		require.Equal(t, id, c.Container())
+		require.Equal(t, id, *c.Container())
 
 		c.ApplyTo(nil)
 
@@ -49,7 +49,7 @@ func TestContainerContext_ApplyTo(t *testing.T) {
 	})
 
 	t.Run("helper functions", func(t *testing.T) {
-		c.ApplyTo(id)
+		c.ApplyTo(&id)
 
 		session.ApplyToAllContainers(c)
 

session/test/container.go

@@ -20,7 +20,8 @@ func ContainerContext() *session.ContainerContext {
 
 	setters[rand.Uint32()%uint32(len(setters))]()
 
-	c.ApplyTo(cidtest.ID())
+	cID := cidtest.ID()
+	c.ApplyTo(&cID)
 
 	return c
 }

storagegroup/storagegroup.go

@@ -93,7 +93,7 @@ func (sg *StorageGroup) Members() []oid.ID {
 	m := make([]oid.ID, len(mV2))
 
 	for i := range mV2 {
-		m[i] = *oid.NewIDFromV2(&mV2[i])
+		_ = m[i].ReadFromV2(mV2[i])
 	}
 
 	return m
@@ -115,8 +115,11 @@ func (sg *StorageGroup) SetMembers(members []oid.ID) {
 			mV2 = make([]refs.ObjectID, ln)
 		}
 
+		var oidV2 refs.ObjectID
+
 		for i := 0; i < ln; i++ {
-			mV2[i] = *members[i].ToV2()
+			members[i].WriteToV2(&oidV2)
+			mV2[i] = oidV2
 		}
 	}
 

storagegroup/storagegroup_test.go

@@ -30,7 +30,7 @@ func TestStorageGroup(t *testing.T) {
 	sg.SetExpirationEpoch(exp)
 	require.Equal(t, exp, sg.ExpirationEpoch())
 
-	members := []oid.ID{*oidtest.ID(), *oidtest.ID()}
+	members := []oid.ID{oidtest.ID(), oidtest.ID()}
 	sg.SetMembers(members)
 	require.Equal(t, members, sg.Members())
 }

storagegroup/test/generate.go

@@ -14,7 +14,7 @@ func StorageGroup() *storagegroup.StorageGroup {
 	x.SetExpirationEpoch(66)
 	x.SetValidationDataSize(322)
 	x.SetValidationDataHash(checksumtest.Checksum())
-	x.SetMembers([]oid.ID{*oidtest.ID(), *oidtest.ID()})
+	x.SetMembers([]oid.ID{oidtest.ID(), oidtest.ID()})
 
 	return x
 }