core: implement System.Json.* interops

pkg/core/interop/json/json.go

@@ -0,0 +1,29 @@
+package json
+
+import (
+	"github.com/nspcc-dev/neo-go/pkg/core/interop"
+	"github.com/nspcc-dev/neo-go/pkg/vm"
+	"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
+)
+
+// Serialize handles System.JSON.Serialize syscall.
+func Serialize(_ *interop.Context, v *vm.VM) error {
+	item := v.Estack().Pop().Item()
+	data, err := stackitem.ToJSON(item)
+	if err != nil {
+		return err
+	}
+	v.Estack().PushVal(data)
+	return nil
+}
+
+// Deserialize handles System.JSON.Deserialize syscall.
+func Deserialize(_ *interop.Context, v *vm.VM) error {
+	data := v.Estack().Pop().Bytes()
+	item, err := stackitem.FromJSON(data)
+	if err != nil {
+		return err
+	}
+	v.Estack().PushVal(item)
+	return nil
+}

pkg/core/interop/json/json_test.go

@@ -0,0 +1,68 @@
+package json
+
+import (
+	"encoding/binary"
+	"testing"
+
+	"github.com/nspcc-dev/neo-go/pkg/vm"
+	"github.com/nspcc-dev/neo-go/pkg/vm/emit"
+	"github.com/nspcc-dev/neo-go/pkg/vm/opcode"
+	"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
+	"github.com/stretchr/testify/require"
+)
+
+var (
+	serializeID   = emit.InteropNameToID([]byte("System.Json.Serialize"))
+	deserializeID = emit.InteropNameToID([]byte("System.Json.Deserialize"))
+)
+
+func getInterop(id uint32) *vm.InteropFuncPrice {
+	switch id {
+	case serializeID:
+		return &vm.InteropFuncPrice{
+			Func: func(v *vm.VM) error { return Serialize(nil, v) },
+		}
+	case deserializeID:
+		return &vm.InteropFuncPrice{
+			Func: func(v *vm.VM) error { return Deserialize(nil, v) },
+		}
+	default:
+		return nil
+	}
+}
+
+func getTestFunc(id uint32, arg interface{}, result interface{}) func(t *testing.T) {
+	prog := make([]byte, 5)
+	prog[0] = byte(opcode.SYSCALL)
+	binary.LittleEndian.PutUint32(prog[1:], id)
+
+	return func(t *testing.T) {
+		v := vm.New()
+		v.RegisterInteropGetter(getInterop)
+		v.LoadScript(prog)
+		v.Estack().PushVal(arg)
+		if result == nil {
+			require.Error(t, v.Run())
+			return
+		}
+		require.NoError(t, v.Run())
+		require.Equal(t, stackitem.Make(result), v.Estack().Pop().Item())
+	}
+}
+
+func TestSerialize(t *testing.T) {
+	t.Run("Serialize", func(t *testing.T) {
+		t.Run("Good", getTestFunc(serializeID, 42, []byte("42")))
+		t.Run("Bad", func(t *testing.T) {
+			arr := stackitem.NewArray([]stackitem.Item{
+				stackitem.NewByteArray(make([]byte, stackitem.MaxSize/2)),
+				stackitem.NewByteArray(make([]byte, stackitem.MaxSize/2)),
+			})
+			getTestFunc(serializeID, arr, nil)(t)
+		})
+	})
+	t.Run("Deserialize", func(t *testing.T) {
+		t.Run("Good", getTestFunc(deserializeID, []byte("42"), 42))
+		t.Run("Bad", getTestFunc(deserializeID, []byte("{]"), nil))
+	})
+}

pkg/core/interops.go

@@ -14,6 +14,7 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/core/interop/crypto"
 	"github.com/nspcc-dev/neo-go/pkg/core/interop/enumerator"
 	"github.com/nspcc-dev/neo-go/pkg/core/interop/iterator"
+	"github.com/nspcc-dev/neo-go/pkg/core/interop/json"
 	"github.com/nspcc-dev/neo-go/pkg/core/interop/runtime"
 	"github.com/nspcc-dev/neo-go/pkg/core/native"
 	"github.com/nspcc-dev/neo-go/pkg/smartcontract"
@@ -105,6 +106,8 @@ var systemInterops = []interop.Function{
 	{Name: "System.Iterator.Key", Func: iterator.Key, Price: 400},
 	{Name: "System.Iterator.Keys", Func: iterator.Keys, Price: 400},
 	{Name: "System.Iterator.Values", Func: iterator.Values, Price: 400},
+	{Name: "System.Json.Deserialize", Func: json.Deserialize, Price: 500000},
+	{Name: "System.Json.Serialize", Func: json.Serialize, Price: 100000},
 	{Name: "System.Runtime.CheckWitness", Func: runtime.CheckWitness, Price: 200, RequiredFlags: smartcontract.AllowStates},
 	{Name: "System.Runtime.GetTime", Func: runtimeGetTime, Price: 1,
 		AllowedTriggers: trigger.Application, RequiredFlags: smartcontract.AllowStates},