rpcsrv: support Map parameter in invokefunction RPC handler

We have smartcontract.ParameterPair structure that can be properly
marshalled and passed to RPC server as an element of smartcontract.Map
structure. However, RPC server can't unmarshal map values properly
without this change.

This change is compatible with C# node.

Signed-off-by: Anna Shaleva <shaleva.ann@nspcc.ru>

pkg/services/rpcsrv/params/param.go

@@ -34,6 +34,13 @@ type (
 		Type  smartcontract.ParamType `json:"type"`
 		Value Param                   `json:"value"`
 	}
+
+	// FuncParamKV represents a pair of function argument parameters
+	// a slice of which is stored in FuncParam of [smartcontract.MapType] type.
+	FuncParamKV struct {
+		Key   FuncParam `json:"key"`
+		Value FuncParam `json:"value"`
+	}
 )
 
 var (
@@ -358,6 +365,21 @@ func (p *Param) GetFuncParam() (FuncParam, error) {
 	return fp, err
 }
 
+// GetFuncParamPair returns a pair of function call parameters.
+func (p *Param) GetFuncParamPair() (FuncParamKV, error) {
+	if p == nil {
+		return FuncParamKV{}, errMissingParameter
+	}
+	// This one doesn't need to be cached, it's used only once.
+	fpp := FuncParamKV{}
+	err := json.Unmarshal(p.RawMessage, &fpp)
+	if err != nil {
+		return FuncParamKV{}, err
+	}
+
+	return fpp, nil
+}
+
 // GetBytesHex returns a []byte value of the parameter if
 // it is a hex-encoded string.
 func (p *Param) GetBytesHex() ([]byte, error) {

pkg/services/rpcsrv/params/param_test.go

@@ -426,6 +426,48 @@ func TestParamGetFuncParam(t *testing.T) {
 	require.NotNil(t, err)
 }
 
+func TestParamGetFuncParamPair(t *testing.T) {
+	fp := FuncParam{
+		Type:  smartcontract.MapType,
+		Value: Param{RawMessage: []byte(`[{"key": {"type": "String", "value": "key1"}, "value": {"type": "Integer", "value": 123}}, {"key": {"type": "String", "value": "key2"}, "value": {"type": "Integer", "value": 456}}]`)},
+	}
+	p := Param{RawMessage: []byte(`{"type": "Map", "value": [{"key": {"type": "String", "value": "key1"}, "value": {"type": "Integer", "value": 123}}, {"key": {"type": "String", "value": "key2"}, "value": {"type": "Integer", "value": 456}}]}`)}
+	newfp, err := p.GetFuncParam()
+	assert.Equal(t, fp, newfp)
+	require.NoError(t, err)
+
+	kvs, err := newfp.Value.GetArray()
+	require.NoError(t, err)
+
+	p1, err := kvs[0].GetFuncParamPair()
+	require.NoError(t, err)
+
+	fp1Key := FuncParam{
+		Type:  smartcontract.StringType,
+		Value: Param{RawMessage: []byte(`"key1"`)},
+	}
+	fp1Value := FuncParam{
+		Type:  smartcontract.IntegerType,
+		Value: Param{RawMessage: []byte(`123`)},
+	}
+	assert.Equal(t, fp1Key, p1.Key)
+	assert.Equal(t, fp1Value, p1.Value)
+
+	p2, err := kvs[1].GetFuncParamPair()
+	require.NoError(t, err)
+
+	fp2Key := FuncParam{
+		Type:  smartcontract.StringType,
+		Value: Param{RawMessage: []byte(`"key2"`)},
+	}
+	fp2Value := FuncParam{
+		Type:  smartcontract.IntegerType,
+		Value: Param{RawMessage: []byte(`456`)},
+	}
+	assert.Equal(t, fp2Key, p2.Key)
+	assert.Equal(t, fp2Value, p2.Value)
+}
+
 func TestParamGetBytesHex(t *testing.T) {
 	in := "602c79718b16e442de58778e148d0b1084e3b2dffd5de6b7b16cee7969282de7"
 	inb, _ := hex.DecodeString(in)

pkg/services/rpcsrv/params/txBuilder.go

@@ -13,14 +13,9 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/vm/opcode"
 )
 
-// ExpandArrayIntoScript pushes all FuncParam parameters from the given array
+// ExpandFuncParameterIntoScript pushes provided FuncParam parameter
-// into the given buffer in the reverse order.
+// into the given buffer.
-func ExpandArrayIntoScript(script *io.BinWriter, slice []Param) error {
+func ExpandFuncParameterIntoScript(script *io.BinWriter, fp FuncParam) error {
-	for j := len(slice) - 1; j >= 0; j-- {
-		fp, err := slice[j].GetFuncParam()
-		if err != nil {
-			return err
-		}
 	switch fp.Type {
 	case smartcontract.ByteArrayType:
 		str, err := fp.Value.GetBytesBase64()
@@ -83,6 +78,15 @@ func ExpandArrayIntoScript(script *io.BinWriter, slice []Param) error {
 		if err != nil {
 			return err
 		}
+	case smartcontract.MapType:
+		val, err := fp.Value.GetArray()
+		if err != nil {
+			return err
+		}
+		err = ExpandMapIntoScriptAndPack(script, val)
+		if err != nil {
+			return err
+		}
 	case smartcontract.AnyType:
 		if fp.Value.IsNull() || len(fp.Value.RawMessage) == 0 {
 			emit.Opcodes(script, opcode.PUSHNULL)
@@ -90,6 +94,21 @@ func ExpandArrayIntoScript(script *io.BinWriter, slice []Param) error {
 	default:
 		return fmt.Errorf("parameter type %v is not supported", fp.Type)
 	}
+	return script.Err
+}
+
+// ExpandArrayIntoScript pushes all FuncParam parameters from the given array
+// into the given buffer in the reverse order.
+func ExpandArrayIntoScript(script *io.BinWriter, slice []Param) error {
+	for j := len(slice) - 1; j >= 0; j-- {
+		fp, err := slice[j].GetFuncParam()
+		if err != nil {
+			return err
+		}
+		err = ExpandFuncParameterIntoScript(script, fp)
+		if err != nil {
+			return fmt.Errorf("param %d: %w", j, err)
+		}
 	}
 	return script.Err
 }
@@ -110,6 +129,32 @@ func ExpandArrayIntoScriptAndPack(script *io.BinWriter, slice []Param) error {
 	return script.Err
 }
 
+// ExpandMapIntoScriptAndPack expands provided array of key-value items into script
+// and packs the resulting pairs in the [stackitem.Map].
+func ExpandMapIntoScriptAndPack(script *io.BinWriter, slice []Param) error {
+	if len(slice) == 0 {
+		emit.Opcodes(script, opcode.NEWMAP)
+		return script.Err
+	}
+	for i := len(slice) - 1; i >= 0; i-- {
+		pair, err := slice[i].GetFuncParamPair()
+		if err != nil {
+			return err
+		}
+		err = ExpandFuncParameterIntoScript(script, pair.Value)
+		if err != nil {
+			return fmt.Errorf("map value %d: %w", i, err)
+		}
+		err = ExpandFuncParameterIntoScript(script, pair.Key)
+		if err != nil {
+			return fmt.Errorf("map key %d: %w", i, err)
+		}
+	}
+	emit.Int(script, int64(len(slice)))
+	emit.Opcodes(script, opcode.PACKMAP)
+	return script.Err
+}
+
 // CreateFunctionInvocationScript creates a script to invoke the given contract with
 // the given parameters.
 func CreateFunctionInvocationScript(contract util.Uint160, method string, param *Param) ([]byte, error) {

pkg/services/rpcsrv/params/tx_builder_test.go

@@ -124,6 +124,17 @@ func TestExpandArrayIntoScript(t *testing.T) {
 			Input:    []Param{{RawMessage: []byte(`{"type": "Integer", "value": "` + bi.String() + `"}`)}},
 			Expected: append([]byte{byte(opcode.PUSHINT256)}, rawInt...),
 		},
+		{
+			Input: []Param{{RawMessage: []byte(`{"type": "Map", "value": [{"key": {"type": "String", "value": "a" }, "value": {"type": "Integer", "value": 1}}, {"key": {"type": "String", "value": "b"}, "value": {"type": "Integer", "value": 2}}]}`)}},
+			Expected: []byte{
+				byte(opcode.PUSH2),                   // value of element #2
+				byte(opcode.PUSHDATA1), 1, byte('b'), // key of element #2
+				byte(opcode.PUSH1),                   // value of element #1
+				byte(opcode.PUSHDATA1), 1, byte('a'), // key of element #1
+				byte(opcode.PUSH2), // map len
+				byte(opcode.PACKMAP),
+			},
+		},
 	}
 	for _, c := range testCases {
 		script := io.NewBufBinWriter()
@@ -142,6 +153,12 @@ func TestExpandArrayIntoScript(t *testing.T) {
 			{RawMessage: []byte(`{"type": "Integer", "value": "` +
 				new(big.Int).Lsh(big.NewInt(1), 255).String() + `"}`)},
 		},
+		{
+			{RawMessage: []byte(`{"type": "Map", "value": [{"key": {"type": "InvalidT", "value": "a" }, "value": {"type": "Integer", "value": 1}}]}`)},
+		},
+		{
+			{RawMessage: []byte(`{"type": "Map", "value": [{"key": {"type": "String", "value": "a" }, "value": {"type": "Integer", "value": "not-an-int"}}]}`)},
+		},
 	}
 	for _, c := range errorCases {
 		script := io.NewBufBinWriter()