codec; Enable custom scale methods (#597)

* checks if type has Encode function

* Added DecodeCustom to handle calling Decode func

DecodeCustom handles calling Decode function for types that have Decode
defined, otherwise uses regular Scale Decoding functions

Signed-off-by: edwardmack <ed@edwardmack.com>

* go fmt'ed

Signed-off-by: edwardmack <ed@edwardmack.com>

* fixed lint rants

Signed-off-by: edwardmack <ed@edwardmack.com>

Co-authored-by: noot <36753753+noot@users.noreply.github.com>

codec/decode_ptr.go

@@ -23,6 +23,23 @@ import (
 	"reflect"
 )
 
+// DecodeCustom check if interface has method Decode, if so use that, otherwise use regular scale decoding
+func DecodeCustom(in []byte, t interface{}) error {
+	someType := reflect.TypeOf(t)
+	_, ok := someType.MethodByName("Decode")
+	if ok {
+		meth := reflect.ValueOf(t).MethodByName("Decode")
+		inVal := []reflect.Value{reflect.ValueOf(in)}
+		res := meth.Call(inVal)
+		err := res[0].Interface()
+		if err != nil {
+			return err.(error)
+		}
+		return nil
+	}
+	return DecodePtr(in, t)
+}
+
 // DecodePtr is the high level function wrapping the specific type decoding functions
 // The results of decode are written to t interface by reference (instead of returning
 //  value as Decode does)

codec/decode_ptr_test.go

@@ -17,9 +17,14 @@ package codec
 
 import (
 	"bytes"
+	"errors"
 	"math/big"
 	"reflect"
 	"testing"
+
+	"github.com/ChainSafe/gossamer/consensus/babe/types"
+	"github.com/ChainSafe/gossamer/crypto/sr25519"
+	"github.com/stretchr/testify/require"
 )
 
 func TestDecodePtrFixedWidthInts(t *testing.T) {
@@ -206,3 +211,78 @@ func TestDecodePtrArrays(t *testing.T) {
 		}
 	}
 }
+
+// test decoding with DecodeCustom on BabeHeader type
+func TestDecodeCustom_DecodeBabeHeader(t *testing.T) {
+	// arbitrary test data
+	expected := &types.BabeHeader{
+		VrfOutput:          [sr25519.VrfOutputLength]byte{0, 91, 50, 25, 214, 94, 119, 36, 71, 216, 33, 152, 85, 184, 34, 120, 61, 161, 164, 223, 76, 53, 40, 246, 76, 38, 235, 204, 43, 31, 179, 28},
+		VrfProof:           [sr25519.VrfProofLength]byte{120, 23, 235, 159, 115, 122, 207, 206, 123, 232, 75, 243, 115, 255, 131, 181, 219, 241, 200, 206, 21, 22, 238, 16, 68, 49, 86, 99, 76, 139, 39, 0, 102, 106, 181, 136, 97, 141, 187, 1, 234, 183, 241, 28, 27, 229, 133, 8, 32, 246, 245, 206, 199, 142, 134, 124, 226, 217, 95, 30, 176, 246, 5, 3},
+		BlockProducerIndex: 17,
+		SlotNumber:         420,
+	}
+	encoded := []byte{0, 91, 50, 25, 214, 94, 119, 36, 71, 216, 33, 152, 85, 184, 34, 120, 61, 161, 164, 223, 76, 53, 40, 246, 76, 38, 235, 204, 43, 31, 179, 28, 120, 23, 235, 159, 115, 122, 207, 206, 123, 232, 75, 243, 115, 255, 131, 181, 219, 241, 200, 206, 21, 22, 238, 16, 68, 49, 86, 99, 76, 139, 39, 0, 102, 106, 181, 136, 97, 141, 187, 1, 234, 183, 241, 28, 27, 229, 133, 8, 32, 246, 245, 206, 199, 142, 134, 124, 226, 217, 95, 30, 176, 246, 5, 3, 17, 0, 0, 0, 0, 0, 0, 0, 164, 1, 0, 0, 0, 0, 0, 0}
+	decodedBabeHeader := new(types.BabeHeader)
+
+	err := DecodeCustom(encoded, decodedBabeHeader)
+	require.Nil(t, err)
+	require.Equal(t, expected, decodedBabeHeader)
+}
+
+// add Decode func to MockTypeA
+func (tr *MockTypeA) Decode(in []byte) error {
+	return DecodePtr(in, tr)
+}
+
+// test decoding for MockTypeA (which has Decode func)
+func TestDecodeCustom_DecodeMockTypeA(t *testing.T) {
+	expected := &MockTypeA{A: "hello"}
+	encoded := []byte{20, 104, 101, 108, 108, 111}
+	mockType := new(MockTypeA)
+
+	err := DecodeCustom(encoded, mockType)
+	require.Nil(t, err)
+	require.Equal(t, expected, mockType)
+}
+
+// test decoding for MockTypeB (which does not have Decode func)
+func TestDecodeCustom_DecodeMockTypeB(t *testing.T) {
+	expected := &MockTypeB{A: "hello"}
+	encoded := []byte{20, 104, 101, 108, 108, 111}
+	mockType := new(MockTypeB)
+
+	err := DecodeCustom(encoded, mockType)
+	require.Nil(t, err)
+	require.Equal(t, expected, mockType)
+}
+
+// add Decode func to MockTypeC which will return fake data (so we'll know when it was called)
+func (tr *MockTypeC) Decode(in []byte) error {
+	tr.A = "goodbye"
+	return nil
+}
+
+// test decoding for MockTypeC (which has Decode func that returns fake data (A: "goodbye"))
+func TestDecodeCustom_DecodeMockTypeC(t *testing.T) {
+	expected := &MockTypeC{A: "goodbye"}
+	encoded := []byte{20, 104, 101, 108, 108, 111}
+	mockType := new(MockTypeC)
+
+	err := DecodeCustom(encoded, mockType)
+	require.Nil(t, err)
+	require.Equal(t, expected, mockType)
+}
+
+// add Decode func to MockTypeD which will return an error
+func (tr *MockTypeD) Decode(in []byte) error {
+	return errors.New("error decoding")
+}
+
+// test decoding for MockTypeD (which has Decode func that returns error)
+func TestDecodeCustom_DecodeMockTypeD(t *testing.T) {
+	encoded := []byte{20, 104, 101, 108, 108, 111}
+	mockType := new(MockTypeD)
+
+	err := DecodeCustom(encoded, mockType)
+	require.EqualError(t, err, "error decoding")
+}

codec/encode.go

@@ -32,6 +32,22 @@ type Encoder struct {
 	Writer io.Writer
 }
 
+// EncodeCustom check if interface has method Encode, if so use that, otherwise use regular scale encoding
+func EncodeCustom(in interface{}) ([]byte, error) {
+	someType := reflect.TypeOf(in)
+	_, ok := someType.MethodByName("Encode")
+	if ok {
+		res := reflect.ValueOf(in).MethodByName("Encode").Call([]reflect.Value{})
+		val := res[0].Interface()
+		err := res[1].Interface()
+		if err != nil {
+			return val.([]byte), err.(error)
+		}
+		return val.([]byte), nil
+	}
+	return Encode(in)
+}
+
 // Encode to byte array
 func Encode(in interface{}) ([]byte, error) {
 	buffer := bytes.Buffer{}

codec/encode_test.go

@@ -18,6 +18,7 @@ package codec
 
 import (
 	"bytes"
+	"errors"
 	"math/big"
 	"reflect"
 	"strings"
@@ -210,3 +211,83 @@ func TestEncodeAndDecodeStringArrayInStruct(t *testing.T) {
 	require.Nil(t, err)
 	require.Equal(t, test, result, "Decoding failed")
 }
+
+// test type for encoding
+type MockTypeA struct {
+	A string
+}
+
+// Encode func for TypeReal that uses actual Scale Encode
+func (tr *MockTypeA) Encode() ([]byte, error) {
+	return Encode(tr)
+}
+
+// test to confirm EncodeCustom is return Scale Encoded result
+func TestEncodeCustomMockTypeA(t *testing.T) {
+	test := &MockTypeA{A: "hello"}
+
+	encCust, err := EncodeCustom(test)
+	require.Nil(t, err)
+
+	encScale, err := Encode(test)
+	require.Nil(t, err)
+
+	require.Equal(t, encScale, encCust)
+}
+
+// test type for encoding, this type does not have Encode func
+type MockTypeB struct {
+	A string
+}
+
+// test to confirm EncodeCustom is return Scale Encoded result
+func TestEncodeCustomMockTypeB(t *testing.T) {
+	test := &MockTypeB{A: "hello"}
+
+	encCust, err := EncodeCustom(test)
+	require.Nil(t, err)
+
+	encScale, err := Encode(test)
+	require.Nil(t, err)
+
+	require.Equal(t, encScale, encCust)
+}
+
+// test types for encoding
+type MockTypeC struct {
+	A string
+}
+
+// Encode func for MockTypeC that return fake byte array [1, 2, 3]
+func (tr *MockTypeC) Encode() ([]byte, error) {
+	return []byte{1, 2, 3}, nil
+}
+
+// test to confirm EncodeCustom is using type's Encode function
+func TestEncodeCustomMockTypeC(t *testing.T) {
+	test := &MockTypeC{A: "hello"}
+	expected := []byte{1, 2, 3}
+
+	encCust, err := EncodeCustom(test)
+	require.Nil(t, err)
+
+	require.Equal(t, expected, encCust)
+}
+
+// test types for encoding
+type MockTypeD struct {
+	A string
+}
+
+// Encode func for MockTypeD that return an error
+func (tr *MockTypeD) Encode() ([]byte, error) {
+	return nil, errors.New("error encoding")
+}
+
+// test to confirm EncodeCustom is handling errors
+func TestEncodeCustomMockTypeD(t *testing.T) {
+	test := &MockTypeD{A: "hello"}
+
+	_, err := EncodeCustom(test)
+	require.EqualError(t, err, "error encoding")
+}

go.mod

@@ -11,8 +11,8 @@ require (
 	github.com/disiqueira/gotree v1.0.0
 	github.com/ethereum/go-ethereum v1.9.6
 	github.com/filecoin-project/go-leb128 v0.0.0-20190212224330-8d79a5489543
-	github.com/golang/protobuf v1.3.2 // indirect
 	github.com/golang/snappy v0.0.1
+	github.com/golangci/golangci-lint v1.23.1 // indirect
 	github.com/google/go-cmp v0.3.1 // indirect
 	github.com/gtank/merlin v0.1.1 // indirect
 	github.com/ipfs/go-datastore v0.3.1
@@ -24,16 +24,12 @@ require (
 	github.com/multiformats/go-multiaddr v0.2.0
 	github.com/naoina/go-stringutil v0.1.0 // indirect
 	github.com/naoina/toml v0.1.1
-	github.com/onsi/ginkgo v1.10.1 // indirect
-	github.com/onsi/gomega v1.7.0 // indirect
 	github.com/opentracing/opentracing-go v1.1.0 // indirect
 	github.com/stretchr/testify v1.4.0
 	github.com/urfave/cli v1.20.0
 	github.com/wasmerio/go-ext-wasm v0.0.0-20191206132826-225d01fcd22c
 	golang.org/x/crypto v0.0.0-20191227163750-53104e6ec876
-	golang.org/x/net v0.0.0-20190916140828-c8589233b77d // indirect
 	golang.org/x/sync v0.0.0-20190911185100-cd5d95a43a6e // indirect
-	gopkg.in/yaml.v2 v2.2.7 // indirect
 )
 
 go 1.13