[#44] checksum: move package from neofs-api-go

Also remove `Checksum` from functions and constants names.

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

checksum/checksum.go

@@ -0,0 +1,181 @@
+package checksum
+
+import (
+	"bytes"
+	"crypto/sha256"
+	"encoding/hex"
+	"fmt"
+
+	"github.com/nspcc-dev/neofs-api-go/v2/refs"
+)
+
+// Checksum represents v2-compatible checksum.
+type Checksum refs.Checksum
+
+// Type represents the enumeration
+// of checksum types.
+type Type uint8
+
+const (
+	// Unknown is an undefined checksum type.
+	Unknown Type = iota
+
+	// SHA256 is a SHA256 checksum type.
+	SHA256
+
+	// TZ is a Tillich-Zemor checksum type.
+	TZ
+)
+
+// NewFromV2 wraps v2 Checksum message to Checksum.
+//
+// Nil refs.Checksum converts to nil.
+func NewFromV2(cV2 *refs.Checksum) *Checksum {
+	return (*Checksum)(cV2)
+}
+
+// New creates and initializes blank Checksum.
+//
+// Defaults:
+//  - sum: nil;
+//  - type: Unknown.
+func New() *Checksum {
+	return NewFromV2(new(refs.Checksum))
+}
+
+// Type returns checksum type.
+func (c *Checksum) Type() Type {
+	switch (*refs.Checksum)(c).GetType() {
+	case refs.SHA256:
+		return SHA256
+	case refs.TillichZemor:
+		return TZ
+	default:
+		return Unknown
+	}
+}
+
+// Sum returns checksum bytes.
+func (c *Checksum) Sum() []byte {
+	return (*refs.Checksum)(c).GetSum()
+}
+
+// SetSHA256 sets checksum to SHA256 hash.
+func (c *Checksum) SetSHA256(v [sha256.Size]byte) {
+	checksum := (*refs.Checksum)(c)
+
+	checksum.SetType(refs.SHA256)
+	checksum.SetSum(v[:])
+}
+
+// SetTillichZemor sets checksum to Tillich-Zemor hash.
+func (c *Checksum) SetTillichZemor(v [64]byte) {
+	checksum := (*refs.Checksum)(c)
+
+	checksum.SetType(refs.TillichZemor)
+	checksum.SetSum(v[:])
+}
+
+// ToV2 converts Checksum to v2 Checksum message.
+//
+// Nil Checksum converts to nil.
+func (c *Checksum) ToV2() *refs.Checksum {
+	return (*refs.Checksum)(c)
+}
+
+func Equal(cs1, cs2 *Checksum) bool {
+	return cs1.Type() == cs2.Type() && bytes.Equal(cs1.Sum(), cs2.Sum())
+}
+
+// Marshal marshals Checksum into a protobuf binary form.
+func (c *Checksum) Marshal() ([]byte, error) {
+	return (*refs.Checksum)(c).StableMarshal(nil)
+}
+
+// Unmarshal unmarshals protobuf binary representation of Checksum.
+func (c *Checksum) Unmarshal(data []byte) error {
+	return (*refs.Checksum)(c).Unmarshal(data)
+}
+
+// MarshalJSON encodes Checksum to protobuf JSON format.
+func (c *Checksum) MarshalJSON() ([]byte, error) {
+	return (*refs.Checksum)(c).MarshalJSON()
+}
+
+// UnmarshalJSON decodes Checksum from protobuf JSON format.
+func (c *Checksum) UnmarshalJSON(data []byte) error {
+	return (*refs.Checksum)(c).UnmarshalJSON(data)
+}
+
+func (c *Checksum) String() string {
+	return hex.EncodeToString((*refs.Checksum)(c).GetSum())
+}
+
+// Parse parses Checksum from its string representation.
+func (c *Checksum) Parse(s string) error {
+	data, err := hex.DecodeString(s)
+	if err != nil {
+		return err
+	}
+
+	var typ refs.ChecksumType
+
+	switch ln := len(data); ln {
+	default:
+		return fmt.Errorf("unsupported checksum length %d", ln)
+	case sha256.Size:
+		typ = refs.SHA256
+	case 64:
+		typ = refs.TillichZemor
+	}
+
+	cV2 := (*refs.Checksum)(c)
+	cV2.SetType(typ)
+	cV2.SetSum(data)
+
+	return nil
+}
+
+// String returns string representation of Type.
+//
+// String mapping:
+//  * TZ: TZ;
+//  * SHA256: SHA256;
+//  * Unknown, default: CHECKSUM_TYPE_UNSPECIFIED.
+func (m Type) String() string {
+	var m2 refs.ChecksumType
+
+	switch m {
+	default:
+		m2 = refs.UnknownChecksum
+	case TZ:
+		m2 = refs.TillichZemor
+	case SHA256:
+		m2 = refs.SHA256
+	}
+
+	return m2.String()
+}
+
+// FromString parses Type from a string representation.
+// It is a reverse action to String().
+//
+// Returns true if s was parsed successfully.
+func (m *Type) FromString(s string) bool {
+	var g refs.ChecksumType
+
+	ok := g.FromString(s)
+
+	if ok {
+		switch g {
+		default:
+			*m = Unknown
+		case refs.TillichZemor:
+			*m = TZ
+		case refs.SHA256:
+			*m = SHA256
+		}
+	}
+
+	return ok
+}

checksum/checksum_test.go

@@ -0,0 +1,175 @@
+package checksum
+
+import (
+	"crypto/rand"
+	"crypto/sha256"
+	"testing"
+
+	"github.com/nspcc-dev/neofs-api-go/v2/refs"
+	"github.com/stretchr/testify/require"
+)
+
+func randSHA256(t *testing.T) [sha256.Size]byte {
+	cSHA256 := [sha256.Size]byte{}
+	_, err := rand.Read(cSHA256[:])
+	require.NoError(t, err)
+
+	return cSHA256
+}
+
+func TestChecksum(t *testing.T) {
+	c := New()
+
+	cSHA256 := [sha256.Size]byte{}
+	_, _ = rand.Read(cSHA256[:])
+
+	c.SetSHA256(cSHA256)
+
+	require.Equal(t, SHA256, c.Type())
+	require.Equal(t, cSHA256[:], c.Sum())
+
+	cV2 := c.ToV2()
+
+	require.Equal(t, refs.SHA256, cV2.GetType())
+	require.Equal(t, cSHA256[:], cV2.GetSum())
+
+	cTZ := [64]byte{}
+	_, _ = rand.Read(cSHA256[:])
+
+	c.SetTillichZemor(cTZ)
+
+	require.Equal(t, TZ, c.Type())
+	require.Equal(t, cTZ[:], c.Sum())
+
+	cV2 = c.ToV2()
+
+	require.Equal(t, refs.TillichZemor, cV2.GetType())
+	require.Equal(t, cTZ[:], cV2.GetSum())
+}
+
+func TestEqualChecksums(t *testing.T) {
+	require.True(t, Equal(nil, nil))
+
+	csSHA := [sha256.Size]byte{}
+	_, _ = rand.Read(csSHA[:])
+
+	cs1 := New()
+	cs1.SetSHA256(csSHA)
+
+	cs2 := New()
+	cs2.SetSHA256(csSHA)
+
+	require.True(t, Equal(cs1, cs2))
+
+	csSHA[0]++
+	cs2.SetSHA256(csSHA)
+
+	require.False(t, Equal(cs1, cs2))
+}
+
+func TestChecksumEncoding(t *testing.T) {
+	cs := New()
+	cs.SetSHA256(randSHA256(t))
+
+	t.Run("binary", func(t *testing.T) {
+		data, err := cs.Marshal()
+		require.NoError(t, err)
+
+		c2 := New()
+		require.NoError(t, c2.Unmarshal(data))
+
+		require.Equal(t, cs, c2)
+	})
+
+	t.Run("json", func(t *testing.T) {
+		data, err := cs.MarshalJSON()
+		require.NoError(t, err)
+
+		cs2 := New()
+		require.NoError(t, cs2.UnmarshalJSON(data))
+
+		require.Equal(t, cs, cs2)
+	})
+
+	t.Run("string", func(t *testing.T) {
+		cs2 := New()
+
+		require.NoError(t, cs2.Parse(cs.String()))
+
+		require.Equal(t, cs, cs2)
+	})
+}
+
+func TestNewChecksumFromV2(t *testing.T) {
+	t.Run("from nil", func(t *testing.T) {
+		var x *refs.Checksum
+
+		require.Nil(t, NewFromV2(x))
+	})
+}
+
+func TestChecksum_ToV2(t *testing.T) {
+	t.Run("nil", func(t *testing.T) {
+		var x *Checksum
+
+		require.Nil(t, x.ToV2())
+	})
+}
+
+func TestNewChecksum(t *testing.T) {
+	t.Run("default values", func(t *testing.T) {
+		chs := New()
+
+		// check initial values
+		require.Equal(t, Unknown, chs.Type())
+		require.Nil(t, chs.Sum())
+
+		// convert to v2 message
+		chsV2 := chs.ToV2()
+
+		require.Equal(t, refs.UnknownChecksum, chsV2.GetType())
+		require.Nil(t, chsV2.GetSum())
+	})
+}
+
+type enumIface interface {
+	FromString(string) bool
+	String() string
+}
+
+type enumStringItem struct {
+	val enumIface
+	str string
+}
+
+func testEnumStrings(t *testing.T, e enumIface, items []enumStringItem) {
+	for _, item := range items {
+		require.Equal(t, item.str, item.val.String())
+
+		s := item.val.String()
+
+		require.True(t, e.FromString(s), s)
+
+		require.EqualValues(t, item.val, e, item.val)
+	}
+
+	// incorrect strings
+	for _, str := range []string{
+		"some string",
+		"undefined",
+	} {
+		require.False(t, e.FromString(str))
+	}
+}
+
+func TestChecksumType_String(t *testing.T) {
+	toPtr := func(v Type) *Type {
+		return &v
+	}
+
+	testEnumStrings(t, new(Type), []enumStringItem{
+		{val: toPtr(TZ), str: "TZ"},
+		{val: toPtr(SHA256), str: "SHA256"},
+		{val: toPtr(Unknown), str: "CHECKSUM_TYPE_UNSPECIFIED"},
+	})
+}