[#170] storagegroup: Refactor and document package functionality

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

storagegroup/doc.go

@@ -0,0 +1,36 @@
+/*
+Package storagegroup provides features to work with information that is
+used for proof of storage in NeoFS system.
+
+StorageGroup type groups verification values for Data Audit sessions:
+	// receive sg info
+
+	sg.ExpirationEpoch() // expiration of the storage group
+	sg.Members() // objects in the group
+	sg.ValidationDataHash() // hash for objects validation
+	sg.ValidationDataSize() // total objects' payload size
+
+Instances can be also used to process NeoFS API V2 protocol messages
+(see neo.fs.v2.storagegroup package in https://github.com/nspcc-dev/neofs-api).
+
+On client side:
+	import "github.com/nspcc-dev/neofs-api-go/v2/storagegroup"
+
+	var msg storagegroup.StorageGroup
+	sg.WriteToV2(&msg)
+
+	// send msg
+
+On server side:
+	// recv msg
+
+	var sg StorageGroupDecimal
+	sg.ReadFromV2(msg)
+
+	// process sg
+
+Using package types in an application is recommended to potentially work with
+different protocol versions with which these types are compatible.
+
+*/
+package storagegroup

storagegroup/storagegroup.go

@@ -7,35 +7,47 @@ import (
 	oid "github.com/nspcc-dev/neofs-sdk-go/object/id"
 )
 
-// StorageGroup represents v2-compatible storage group.
+// StorageGroup represents storage group of the NeoFS objects.
+//
+// StorageGroup is mutually compatible with github.com/nspcc-dev/neofs-api-go/v2/storagegroup.StorageGroup
+// message. See ReadFromMessageV2 / WriteToMessageV2 methods.
+//
+// Instances can be created using built-in var declaration.
+//
+// Note that direct typecast is not safe and may result in loss of compatibility:
+// 	_ = StorageGroup(storagegroup.StorageGroup) // not recommended
 type StorageGroup storagegroup.StorageGroup
 
-// NewFromV2 wraps v2 StorageGroup message to StorageGroup.
+// ReadFromV2 reads StorageGroup from the storagegroup.StorageGroup message.
 //
-// Nil storagegroup.StorageGroup converts to nil.
-func NewFromV2(aV2 *storagegroup.StorageGroup) *StorageGroup {
-	return (*StorageGroup)(aV2)
+// See also WriteToV2.
+func (sg *StorageGroup) ReadFromV2(m storagegroup.StorageGroup) {
+	*sg = StorageGroup(m)
 }
 
-// New creates and initializes blank StorageGroup.
+// WriteToV2 writes StorageGroup to the storagegroup.StorageGroup message.
+// The message must not be nil.
 //
-// Defaults:
-//  - size: 0;
-//  - exp: 0;
-//  - members: nil;
-//  - hash: nil.
-func New() *StorageGroup {
-	return NewFromV2(new(storagegroup.StorageGroup))
+// See also ReadFromV2.
+func (sg StorageGroup) WriteToV2(m *storagegroup.StorageGroup) {
+	*m = (storagegroup.StorageGroup)(sg)
 }
 
 // ValidationDataSize returns total size of the payloads
 // of objects in the storage group.
-func (sg *StorageGroup) ValidationDataSize() uint64 {
-	return (*storagegroup.StorageGroup)(sg).GetValidationDataSize()
+//
+// Zero StorageGroup has 0 data size.
+//
+// See also SetValidationDataSize.
+func (sg StorageGroup) ValidationDataSize() uint64 {
+	v2 := (storagegroup.StorageGroup)(sg)
+	return v2.GetValidationDataSize()
 }
 
 // SetValidationDataSize sets total size of the payloads
 // of objects in the storage group.
+//
+// See also ValidationDataSize.
 func (sg *StorageGroup) SetValidationDataSize(epoch uint64) {
 	(*storagegroup.StorageGroup)(sg).SetValidationDataSize(epoch)
 }
@@ -71,20 +83,32 @@ func (sg *StorageGroup) SetValidationDataHash(hash checksum.Checksum) {
 
 // ExpirationEpoch returns last NeoFS epoch number
 // of the storage group lifetime.
-func (sg *StorageGroup) ExpirationEpoch() uint64 {
-	return (*storagegroup.StorageGroup)(sg).GetExpirationEpoch()
+//
+// Zero StorageGroup has 0 expiration epoch.
+//
+// See also SetExpirationEpoch.
+func (sg StorageGroup) ExpirationEpoch() uint64 {
+	v2 := (storagegroup.StorageGroup)(sg)
+	return v2.GetExpirationEpoch()
 }
 
 // SetExpirationEpoch sets last NeoFS epoch number
 // of the storage group lifetime.
+//
+// See also ExpirationEpoch.
 func (sg *StorageGroup) SetExpirationEpoch(epoch uint64) {
 	(*storagegroup.StorageGroup)(sg).SetExpirationEpoch(epoch)
 }
 
 // Members returns strictly ordered list of
 // storage group member objects.
-func (sg *StorageGroup) Members() []oid.ID {
-	mV2 := (*storagegroup.StorageGroup)(sg).GetMembers()
+//
+// Zero StorageGroup has nil members value.
+//
+// See also SetMembers.
+func (sg StorageGroup) Members() []oid.ID {
+	v2 := (storagegroup.StorageGroup)(sg)
+	mV2 := v2.GetMembers()
 
 	if mV2 == nil {
 		return nil
@@ -101,6 +125,8 @@ func (sg *StorageGroup) Members() []oid.ID {
 
 // SetMembers sets strictly ordered list of
 // storage group member objects.
+//
+// See also Members.
 func (sg *StorageGroup) SetMembers(members []oid.ID) {
 	mV2 := (*storagegroup.StorageGroup)(sg).GetMembers()
 
@@ -126,29 +152,57 @@ func (sg *StorageGroup) SetMembers(members []oid.ID) {
 	(*storagegroup.StorageGroup)(sg).SetMembers(mV2)
 }
 
-// ToV2 converts StorageGroup to v2 StorageGroup message.
-//
-// Nil StorageGroup converts to nil.
-func (sg *StorageGroup) ToV2() *storagegroup.StorageGroup {
-	return (*storagegroup.StorageGroup)(sg)
-}
-
 // Marshal marshals StorageGroup into a protobuf binary form.
-func (sg *StorageGroup) Marshal() ([]byte, error) {
-	return (*storagegroup.StorageGroup)(sg).StableMarshal(nil)
+//
+// See also Unmarshal.
+func (sg StorageGroup) Marshal() ([]byte, error) {
+	v2 := (storagegroup.StorageGroup)(sg)
+	return v2.StableMarshal(nil)
 }
 
 // Unmarshal unmarshals protobuf binary representation of StorageGroup.
+//
+// See also Marshal.
 func (sg *StorageGroup) Unmarshal(data []byte) error {
-	return (*storagegroup.StorageGroup)(sg).Unmarshal(data)
+	v2 := (*storagegroup.StorageGroup)(sg)
+	err := v2.Unmarshal(data)
+	if err != nil {
+		return err
+	}
+
+	return formatCheck(v2)
 }
 
 // MarshalJSON encodes StorageGroup to protobuf JSON format.
-func (sg *StorageGroup) MarshalJSON() ([]byte, error) {
-	return (*storagegroup.StorageGroup)(sg).MarshalJSON()
+//
+// See also UnmarshalJSON.
+func (sg StorageGroup) MarshalJSON() ([]byte, error) {
+	v2 := (storagegroup.StorageGroup)(sg)
+	return v2.MarshalJSON()
 }
 
 // UnmarshalJSON decodes StorageGroup from protobuf JSON format.
+//
+// See also MarshalJSON.
 func (sg *StorageGroup) UnmarshalJSON(data []byte) error {
-	return (*storagegroup.StorageGroup)(sg).UnmarshalJSON(data)
+	v2 := (*storagegroup.StorageGroup)(sg)
+	err := v2.UnmarshalJSON(data)
+	if err != nil {
+		return err
+	}
+
+	return formatCheck(v2)
+}
+
+func formatCheck(v2 *storagegroup.StorageGroup) error {
+	var oID oid.ID
+
+	for _, m := range v2.GetMembers() {
+		err := oID.ReadFromV2(m)
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
 }

storagegroup/storagegroup_test.go

@@ -1,9 +1,13 @@
 package storagegroup_test
 
 import (
+	"crypto/sha256"
 	"testing"
 
+	"github.com/nspcc-dev/neofs-api-go/v2/refs"
 	storagegroupV2 "github.com/nspcc-dev/neofs-api-go/v2/storagegroup"
+	storagegroupV2test "github.com/nspcc-dev/neofs-api-go/v2/storagegroup/test"
+	"github.com/nspcc-dev/neofs-sdk-go/checksum"
 	checksumtest "github.com/nspcc-dev/neofs-sdk-go/checksum/test"
 	oid "github.com/nspcc-dev/neofs-sdk-go/object/id"
 	oidtest "github.com/nspcc-dev/neofs-sdk-go/object/id/test"
@@ -13,7 +17,7 @@ import (
 )
 
 func TestStorageGroup(t *testing.T) {
-	sg := storagegroup.New()
+	var sg storagegroup.StorageGroup
 
 	sz := uint64(13)
 	sg.SetValidationDataSize(sz)
@@ -35,6 +39,56 @@ func TestStorageGroup(t *testing.T) {
 	require.Equal(t, members, sg.Members())
 }
 
+func TestStorageGroup_ReadFromV2(t *testing.T) {
+	t.Run("from zero", func(t *testing.T) {
+		var (
+			x  storagegroup.StorageGroup
+			v2 storagegroupV2.StorageGroup
+		)
+
+		x.ReadFromV2(v2)
+
+		require.Zero(t, x.ExpirationEpoch())
+		require.Zero(t, x.ValidationDataSize())
+		_, set := x.ValidationDataHash()
+		require.False(t, set)
+		require.Zero(t, x.Members())
+	})
+
+	t.Run("from non-zero", func(t *testing.T) {
+		var (
+			x  storagegroup.StorageGroup
+			v2 = storagegroupV2test.GenerateStorageGroup(false)
+		)
+
+		// https://github.com/nspcc-dev/neofs-api-go/issues/394
+		v2.SetMembers(generateOIDList())
+
+		size := v2.GetValidationDataSize()
+		epoch := v2.GetExpirationEpoch()
+		mm := v2.GetMembers()
+		hashV2 := v2.GetValidationHash()
+
+		x.ReadFromV2(*v2)
+
+		require.Equal(t, epoch, x.ExpirationEpoch())
+		require.Equal(t, size, x.ValidationDataSize())
+
+		var hash checksum.Checksum
+		hash.ReadFromV2(*hashV2)
+		h, set := x.ValidationDataHash()
+		require.True(t, set)
+		require.Equal(t, hash, h)
+
+		var oidV2 refs.ObjectID
+
+		for i, m := range mm {
+			x.Members()[i].WriteToV2(&oidV2)
+			require.Equal(t, m, oidV2)
+		}
+	})
+}
+
 func TestStorageGroupEncoding(t *testing.T) {
 	sg := storagegrouptest.StorageGroup()
 
@@ -42,7 +96,7 @@ func TestStorageGroupEncoding(t *testing.T) {
 		data, err := sg.Marshal()
 		require.NoError(t, err)
 
-		sg2 := storagegroup.New()
+		var sg2 storagegroup.StorageGroup
 		require.NoError(t, sg2.Unmarshal(data))
 
 		require.Equal(t, sg, sg2)
@@ -52,32 +106,58 @@ func TestStorageGroupEncoding(t *testing.T) {
 		data, err := sg.MarshalJSON()
 		require.NoError(t, err)
 
-		sg2 := storagegroup.New()
+		var sg2 storagegroup.StorageGroup
 		require.NoError(t, sg2.UnmarshalJSON(data))
 
 		require.Equal(t, sg, sg2)
 	})
 }
 
-func TestNewFromV2(t *testing.T) {
-	t.Run("from nil", func(t *testing.T) {
-		var x *storagegroupV2.StorageGroup
+func TestStorageGroup_WriteToV2(t *testing.T) {
+	t.Run("zero to v2", func(t *testing.T) {
+		var (
+			x  storagegroup.StorageGroup
+			v2 storagegroupV2.StorageGroup
+		)
 
-		require.Nil(t, storagegroup.NewFromV2(x))
+		x.WriteToV2(&v2)
+
+		require.Nil(t, v2.GetValidationHash())
+		require.Nil(t, v2.GetMembers())
+		require.Zero(t, v2.GetValidationDataSize())
+		require.Zero(t, v2.GetExpirationEpoch())
 	})
+
+	t.Run("non-zero to v2", func(t *testing.T) {
+		var (
+			x  = storagegrouptest.StorageGroup()
+			v2 storagegroupV2.StorageGroup
+		)
+
+		x.WriteToV2(&v2)
+
+		require.Equal(t, x.ExpirationEpoch(), v2.GetExpirationEpoch())
+		require.Equal(t, x.ValidationDataSize(), v2.GetValidationDataSize())
+
+		var hash checksum.Checksum
+		hash.ReadFromV2(*v2.GetValidationHash())
+
+		h, set := x.ValidationDataHash()
+		require.True(t, set)
+		require.Equal(t, h, hash)
+
+		var oidV2 refs.ObjectID
+
+		for i, m := range x.Members() {
+			m.WriteToV2(&oidV2)
+			require.Equal(t, oidV2, v2.GetMembers()[i])
 		}
-
-func TestStorageGroup_ToV2(t *testing.T) {
-	t.Run("nil", func(t *testing.T) {
-		var x *storagegroup.StorageGroup
-
-		require.Nil(t, x.ToV2())
 	})
 }
 
 func TestNew(t *testing.T) {
 	t.Run("default values", func(t *testing.T) {
-		sg := storagegroup.New()
+		var sg storagegroup.StorageGroup
 
 		// check initial values
 		require.Nil(t, sg.Members())
@@ -85,13 +165,19 @@ func TestNew(t *testing.T) {
 		require.False(t, set)
 		require.Zero(t, sg.ExpirationEpoch())
 		require.Zero(t, sg.ValidationDataSize())
-
-		// convert to v2 message
-		sgV2 := sg.ToV2()
-
-		require.Nil(t, sgV2.GetMembers())
-		require.Nil(t, sgV2.GetValidationHash())
-		require.Zero(t, sgV2.GetExpirationEpoch())
-		require.Zero(t, sgV2.GetValidationDataSize())
 	})
 }
+
+func generateOIDList() []refs.ObjectID {
+	const size = 3
+
+	mmV2 := make([]refs.ObjectID, size)
+	for i := 0; i < size; i++ {
+		oidV2 := make([]byte, sha256.Size)
+		oidV2[i] = byte(i)
+
+		mmV2[i].SetValue(oidV2)
+	}
+
+	return mmV2
+}

storagegroup/test/doc.go

@@ -0,0 +1,13 @@
+/*
+Package storagegrouptest provides functions for convenient testing of storagegroup 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 storagegrouptest "github.com/nspcc-dev/neofs-sdk-go/storagegroup/test"
+
+	val := storagegrouptest.StorageGroup()
+	// test the value
+
+*/
+package storagegrouptest

storagegroup/test/generate.go

@@ -8,8 +8,8 @@ import (
 )
 
 // StorageGroup returns random storagegroup.StorageGroup.
-func StorageGroup() *storagegroup.StorageGroup {
-	x := storagegroup.New()
+func StorageGroup() storagegroup.StorageGroup {
+	var x storagegroup.StorageGroup
 
 	x.SetExpirationEpoch(66)
 	x.SetValidationDataSize(322)