[#186] v2/netmap: Add JSON converter for placement policy

Signed-off-by: Alex Vanin <alexey@nspcc.ru>

go.mod

@@ -3,6 +3,7 @@ module github.com/nspcc-dev/neofs-api-go
 go 1.14
 
 require (
+	github.com/alecthomas/participle v0.6.0
 	github.com/golang/protobuf v1.4.3
 	github.com/google/uuid v1.1.1
 	github.com/mr-tron/base58 v1.1.2

go.sum

@@ -11,6 +11,9 @@ github.com/Workiva/go-datastructures v1.0.50/go.mod h1:Z+F2Rca0qCsVYDS8z7bAGm8f3
 github.com/abiosoft/ishell v2.0.0+incompatible/go.mod h1:HQR9AqF2R3P4XXpMpI0NAzgHf/aS6+zVXRj14cVk9qg=
 github.com/abiosoft/readline v0.0.0-20180607040430-155bce2042db/go.mod h1:rB3B4rKii8V21ydCbIzH5hZiCQE7f5E9SzUb/ZZx530=
 github.com/aead/siphash v1.0.1/go.mod h1:Nywa3cDsYNNK3gaciGTWPwHt0wlpNV15vwmswBAUSII=
+github.com/alecthomas/participle v0.6.0 h1:Pvo8XUCQKgIywVjz/+Ci3IsjGg+g/TdKkMcfgghKCEw=
+github.com/alecthomas/participle v0.6.0/go.mod h1:HfdmEuwvr12HXQN44HPWXR0lHmVolVYe4dyL6lQ3duY=
+github.com/alecthomas/repr v0.0.0-20181024024818-d37bc2a10ba1/go.mod h1:xTS7Pm1pD1mvyM075QCDSRqH6qRLXylzS24ZTpRiSzQ=
 github.com/alecthomas/template v0.0.0-20160405071501-a0175ee3bccc/go.mod h1:LOuyumcjzFXgccqObfd/Ljyb9UuFJ6TxHnclSeseNhc=
 github.com/alecthomas/template v0.0.0-20190718012654-fb15b899a751/go.mod h1:LOuyumcjzFXgccqObfd/Ljyb9UuFJ6TxHnclSeseNhc=
 github.com/alecthomas/units v0.0.0-20151022065526-2efee857e7cf/go.mod h1:ybxpYRFXyAe+OPACYpWeL0wqObRcbAqCMya13uyzqw0=

v2/netmap/json.go

@@ -34,3 +34,27 @@ func NodeInfoFromJSON(data []byte) (*NodeInfo, error) {
 
 	return NodeInfoFromGRPCMessage(msg), nil
 }
+
+func PlacementPolicyToJSON(n *PlacementPolicy) ([]byte, error) {
+	if n == nil {
+		return nil, errEmptyInput
+	}
+
+	msg := PlacementPolicyToGRPCMessage(n)
+
+	return protojson.MarshalOptions{EmitUnpopulated: true}.Marshal(msg)
+}
+
+func PlacementPolicyFromJSON(data []byte) (*PlacementPolicy, error) {
+	if len(data) == 0 {
+		return nil, errEmptyInput
+	}
+
+	msg := new(netmap.PlacementPolicy)
+
+	if err := protojson.Unmarshal(data, msg); err != nil {
+		return nil, err
+	}
+
+	return PlacementPolicyFromGRPCMessage(msg), nil
+}

v2/netmap/json_test.go

@@ -28,3 +28,25 @@ func TestNodeInfoJSON(t *testing.T) {
 		require.Error(t, err)
 	})
 }
+
+func TestPlacementPolicyJSON(t *testing.T) {
+	exp := generatePolicy(3)
+
+	t.Run("non empty", func(t *testing.T) {
+		data, err := netmap.PlacementPolicyToJSON(exp)
+		require.NoError(t, err)
+
+		got, err := netmap.PlacementPolicyFromJSON(data)
+		require.NoError(t, err)
+
+		require.Equal(t, exp, got)
+	})
+
+	t.Run("empty", func(t *testing.T) {
+		_, err := netmap.PlacementPolicyToJSON(nil)
+		require.Error(t, err)
+
+		_, err = netmap.PlacementPolicyFromJSON(nil)
+		require.Error(t, err)
+	})
+}