*: Affirm IDs as arrays

This continues cde122e and finally
commits to supporting identifiers as fixed-length byte arrays. Since
their format has not changed so far, this is unlikely to happen in the
near foreseeable future. The benefit is the user's code simplification
code and the abandonment of some no longer needed methods (they are
marked deprecated).

Signed-off-by: Leonard Lyubich <leonard@morphbits.io>

container/container_internal_test.go

@@ -66,7 +66,7 @@ func TestContainer_CopyTo(t *testing.T) {
 		require.True(t, container.Owner() == dst.Owner())
 
 		newOwner := usertest.ID()
-		dst.v2.GetOwnerID().SetValue(newOwner.WalletBytes())
+		dst.v2.GetOwnerID().SetValue(newOwner[:])
 
 		require.False(t, container.Owner() == dst.Owner())
 	})

container/id/id.go

@@ -19,10 +19,6 @@ const Size = sha256.Size
 // message. See ReadFromV2 / WriteToV2 methods.
 //
 // Instances can be created using built-in var declaration.
-//
-// Note that direct typecast is not safe and may result in loss of compatibility:
-//
-//	_ = ID([32]byte) // not recommended
 type ID [Size]byte
 
 // ReadFromV2 reads ID from the refs.ContainerID message.
@@ -48,6 +44,7 @@ func (id ID) WriteToV2(m *refs.ContainerID) {
 // Zero ID is all zeros.
 //
 // See also Decode.
+// Deprecated: use id[:] instead.
 func (id ID) Encode(dst []byte) {
 	if l := len(dst); l < Size {
 		panic(fmt.Sprintf("destination length is less than %d bytes: %d", Size, l))
@@ -63,8 +60,6 @@ func (id ID) Encode(dst []byte) {
 // remains unchanged.
 //
 // Decode doesn't mutate src.
-//
-// See also Encode.
 func (id *ID) Decode(src []byte) error {
 	if len(src) != Size {
 		return fmt.Errorf("invalid length %d", len(src))
@@ -76,6 +71,7 @@ func (id *ID) Decode(src []byte) error {
 }
 
 // SetSHA256 sets container identifier value to SHA256 checksum of container structure.
+// Deprecated: use direct assignment instead.
 func (id *ID) SetSHA256(v [sha256.Size]byte) {
 	*id = v
 }
@@ -125,5 +121,5 @@ func (id ID) String() string {
 //
 // See also [container.Container.CalculateID], [container.Container.AssertID].
 func (id *ID) FromBinary(cnr []byte) {
-	id.SetSHA256(sha256.Sum256(cnr))
+	*id = sha256.Sum256(cnr)
 }

container/id/test/id.go

@@ -42,8 +42,5 @@ loop:
 // with specified checksum.
 // Deprecated: use [ID], [OtherID] or manual creation instead.
 func IDWithChecksum(cs [sha256.Size]byte) cid.ID {
-	var id cid.ID
-	id.SetSHA256(cs)
-
-	return id
+	return cs
 }

eacl/table.go

@@ -198,10 +198,7 @@ func NewTableFromV2(table *v2acl.Table) *Table {
 			t.cid = new(cid.ID)
 		}
 
-		var h [cid.Size]byte
-
-		copy(h[:], id.GetValue())
-		t.cid.SetSHA256(h)
+		copy(t.cid[:], id.GetValue())
 	}
 
 	// set eacl records

netmap/netmap.go

@@ -149,6 +149,7 @@ func flattenNodes(ns []nodes) nodes {
 // the fixed NetMap and parameters.
 func (m NetMap) PlacementVectors(vectors [][]NodeInfo, objectID oid.ID) ([][]NodeInfo, error) {
 	pivot := make([]byte, oid.Size)
+	copy(pivot, objectID[:])
 	objectID.Encode(pivot)
 
 	h := hrw.WrapBytes(pivot)
@@ -180,7 +181,7 @@ func (m NetMap) ContainerNodes(p PlacementPolicy, containerID cid.ID) ([][]NodeI
 	c.setCBF(p.backupFactor)
 
 	pivot := make([]byte, cid.Size)
-	containerID.Encode(pivot)
+	copy(pivot, containerID[:])
 	c.setPivot(pivot)
 
 	if err := c.processFilters(p); err != nil {

object/fmt.go

@@ -55,10 +55,7 @@ func (o *Object) VerifyPayloadChecksum() error {
 
 // CalculateID calculates identifier for the object.
 func (o *Object) CalculateID() (oid.ID, error) {
-	var id oid.ID
-	id.SetSHA256(sha256.Sum256(o.ToV2().GetHeader().StableMarshal(nil)))
-
-	return id, nil
+	return sha256.Sum256(o.ToV2().GetHeader().StableMarshal(nil)), nil
 }
 
 // CalculateAndSetID calculates identifier for the object

object/id/id.go

@@ -20,10 +20,6 @@ const Size = sha256.Size
 // message. See ReadFromV2 / WriteToV2 methods.
 //
 // Instances can be created using built-in var declaration.
-//
-// Note that direct typecast is not safe and may result in loss of compatibility:
-//
-//	_ = ID([32]byte{}) // not recommended
 type ID [Size]byte
 
 // ReadFromV2 reads ID from the refs.ObjectID message. Returns an error if
@@ -48,6 +44,7 @@ func (id ID) WriteToV2(m *refs.ObjectID) {
 // Zero ID is all zeros.
 //
 // See also Decode.
+// Deprecated: use id[:] instead.
 func (id ID) Encode(dst []byte) {
 	if l := len(dst); l < Size {
 		panic(fmt.Sprintf("destination length is less than %d bytes: %d", Size, l))
@@ -58,13 +55,11 @@ func (id ID) Encode(dst []byte) {
 
 // Decode decodes src bytes into ID.
 //
-// Decode expects that src has [Size] bytes length. If the input is malformed,
+// Decode expects that src has [IDSize] 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) != Size {
 		return fmt.Errorf("invalid length %d", len(src))
@@ -76,6 +71,7 @@ func (id *ID) Decode(src []byte) error {
 }
 
 // SetSHA256 sets object identifier value to SHA256 checksum.
+// Deprecated: use direct assignment instead.
 func (id *ID) SetSHA256(v [sha256.Size]byte) {
 	*id = v
 }

object/id/id_test.go

@@ -25,30 +25,19 @@ func randSHA256Checksum(t *testing.T) (cs [sha256.Size]byte) {
 func TestIDV2(t *testing.T) {
 	var id oid.ID
 
-	checksum := [sha256.Size]byte{}
-
-	_, err := rand.Read(checksum[:])
+	_, err := rand.Read(id[:])
 	require.NoError(t, err)
 
-	id.SetSHA256(checksum)
-
 	var idV2 refs.ObjectID
 	id.WriteToV2(&idV2)
 
-	require.Equal(t, checksum[:], idV2.GetValue())
+	require.Equal(t, id[:], idV2.GetValue())
 }
 
 func TestID_Equal(t *testing.T) {
-	cs := randSHA256Checksum(t)
-
-	var id1 oid.ID
-	id1.SetSHA256(cs)
-
-	var id2 oid.ID
-	id2.SetSHA256(cs)
-
-	var id3 oid.ID
-	id3.SetSHA256(randSHA256Checksum(t))
+	id1 := oidtest.ID()
+	id2 := id1
+	id3 := oidtest.OtherID(id1)
 
 	require.True(t, id1.Equals(id2))
 	require.False(t, id1.Equals(id3))

session/container_test.go

@@ -137,8 +137,10 @@ func TestContainerProtocolV2(t *testing.T) {
 				require.Equal(t, usrID, val.Issuer())
 			},
 			breakSign: func(m *v2session.Token) {
-				id := m.GetBody().GetOwnerID().GetValue()
-				copy(id, usertest.ID().WalletBytes())
+				otherUsr := usertest.OtherID(usrID)
+				var mID refs.OwnerID
+				otherUsr.WriteToV2(&mID)
+				m.GetBody().SetOwnerID(&mID)
 			},
 		},
 		{

session/object_test.go

@@ -142,8 +142,10 @@ func TestObjectProtocolV2(t *testing.T) {
 				require.Equal(t, usrID, val.Issuer())
 			},
 			breakSign: func(m *v2session.Token) {
-				id := m.GetBody().GetOwnerID().GetValue()
-				copy(id, usertest.ID().WalletBytes())
+				otherUsr := usertest.OtherID(usrID)
+				var mID refs.OwnerID
+				otherUsr.WriteToV2(&mID)
+				m.GetBody().SetOwnerID(&mID)
 			},
 		},
 		{

user/example_test.go

@@ -15,17 +15,6 @@ func ExampleID_SetScriptHash() {
 	id.SetScriptHash(scriptHash)
 }
 
-// ID is compatible with the NeoFS Smart Contract API.
-func ExampleID_WalletBytes() {
-	var id user.ID
-	// ...
-
-	wallet := id.WalletBytes()
-	_ = wallet
-
-	// use wallet in call
-}
-
 // Encoding mechanisms are used to transfer identifiers on client.
 func ExampleID_EncodeToString() {
 	var id user.ID

user/id.go

@@ -15,7 +15,7 @@ import (
 // IDSize is the size of an [ID] in bytes.
 const IDSize = 25
 
-// ID identifies users of the NeoFS system.
+// ID identifies users of the NeoFS system and represents Neo3 account address.
 //
 // ID implements built-in comparable interface.
 //
@@ -68,6 +68,7 @@ func (x *ID) SetScriptHash(scriptHash util.Uint160) {
 // Make a copy if you need to change it.
 //
 // See also Neo3 wallet docs.
+// Deprecated: use x[:] instead.
 func (x ID) WalletBytes() []byte {
 	return x[:]
 }

user/id_test.go

@@ -94,13 +94,7 @@ func TestV2_ID(t *testing.T) {
 func TestID_EncodeToString(t *testing.T) {
 	const s = "NXWcEedga62wcBmfb9dPwar3vbbZJrMtT1"
 	b := [user.IDSize]byte{53, 127, 54, 116, 58, 70, 206, 247, 185, 103, 214, 89, 184, 42, 40, 234, 173, 68, 209, 25, 168, 14, 134, 47, 224}
-	var id user.ID
-
-	var m refs.OwnerID
-	m.SetValue(b[:])
-	require.NoError(t, id.ReadFromV2(m))
-
-	require.Equal(t, s, id.EncodeToString())
+	require.Equal(t, s, user.ID(b).EncodeToString())
 }
 
 func TestID_DecodeString(t *testing.T) {