Add map decoder to be used by EVM and other implementations.

pkg/types/map_decoder.go

@@ -0,0 +1,8 @@
+package types
+
+import "context"
+
+type MapDecoder interface {
+	DecodeSingle(ctx context.Context, raw []byte, itemType string) (map[string]any, error)
+	DecodeMany(ctx context.Context, raw []byte, itemType string) ([]map[string]any, error)
+}

pkg/utils/map_decoder.go

@@ -0,0 +1,242 @@
+package utils
+
+import (
+	"context"
+	"errors"
+	"math/big"
+	"reflect"
+	"strconv"
+
+	"github.com/mitchellh/mapstructure"
+
+	"github.com/smartcontractkit/chainlink-relay/pkg/types"
+)
+
+func DecoderFromMapDecoder(decoder types.MapDecoder, extraHooks ...mapstructure.DecodeHookFunc) (types.Decoder, error) {
+	if decoder == nil {
+		return nil, errors.New("decoder must not be nil")
+	}
+
+	numExtraHooks := len(extraHooks)
+	hooks := make([]mapstructure.DecodeHookFunc, numExtraHooks+2)
+	copy(hooks, extraHooks)
+	hooks[numExtraHooks] = SliceToArrayVerifySizeHook
+	hooks[numExtraHooks+1] = BigIntHook
+	return &mapDecoder{decoder: decoder, hooks: hooks}, nil
+}
+
+type mapDecoder struct {
+	decoder types.MapDecoder
+	hooks   []mapstructure.DecodeHookFunc
+}
+
+func (m *mapDecoder) Decode(ctx context.Context, raw []byte, into any, itemType string) error {
+	rInto := reflect.ValueOf(into)
+	if rInto.Kind() != reflect.Pointer {
+		return types.InvalidTypeError{}
+	}
+
+	elm := reflect.Indirect(rInto)
+	switch elm.Kind() {
+	case reflect.Array:
+		return m.decodeMultiple(ctx, raw, arrayProvider(elm), itemType)
+	case reflect.Slice:
+		return m.decodeMultiple(ctx, raw, sliceProvider(elm), itemType)
+	default:
+		rawMap, err := m.decoder.DecodeSingle(ctx, raw, itemType)
+		if err != nil {
+			return err
+		}
+		return m.mapToItem(rawMap, into)
+	}
+}
+
+// VerifyFieldMaps is a utility for verifying the keys exactly match the fields
+// it is not done in Decode directly as it can often be more efficiently by MapDecoders
+// in the case of DecodeMany
+func VerifyFieldMaps(fields []string, result map[string]any) error {
+	for _, field := range fields {
+		if _, ok := result[field]; !ok {
+			return types.InvalidEncodingError{}
+		}
+	}
+
+	if len(fields) != len(result) {
+		return types.InvalidEncodingError{}
+	}
+
+	return nil
+}
+
+func arrayProvider(rInto reflect.Value) func(size int) (reflect.Value, error) {
+	return func(size int) (reflect.Value, error) {
+		if rInto.Len() != size {
+			return reflect.Value{}, types.WrongNumberOfElements{}
+		}
+		return rInto, nil
+	}
+}
+
+func sliceProvider(rInto reflect.Value) func(size int) (reflect.Value, error) {
+	return func(size int) (reflect.Value, error) {
+		element := reflect.MakeSlice(rInto.Type(), size, size)
+		rInto.Set(element)
+		return rInto, nil
+	}
+}
+
+func (m *mapDecoder) decodeMultiple(ctx context.Context, raw []byte, init func(size int) (reflect.Value, error), itemType string) error {
+	decoded, err := m.decoder.DecodeMany(ctx, raw, itemType)
+	if err != nil {
+		return err
+	}
+
+	rInto, err := init(len(decoded))
+	if err != nil {
+		return err
+	}
+
+	for i, singleDecode := range decoded {
+		if err = m.mapToItem(singleDecode, rInto.Index(i).Addr().Interface()); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func BigIntHook(_, to reflect.Type, data any) (any, error) {
+	if to == reflect.TypeOf(&big.Int{}) {
+		bigInt := big.NewInt(0)
+
+		switch v := data.(type) {
+		case float64:
+			bigInt.SetInt64(int64(v))
+		case float32:
+			bigInt.SetInt64(int64(v))
+		case int:
+			bigInt.SetInt64(int64(v))
+		case int8:
+			bigInt.SetInt64(int64(v))
+		case int16:
+			bigInt.SetInt64(int64(v))
+		case int32:
+			bigInt.SetInt64(int64(v))
+		case int64:
+			bigInt.SetInt64(v)
+		case uint:
+			bigInt.SetUint64(uint64(v))
+		case uint8:
+			bigInt.SetUint64(uint64(v))
+		case uint16:
+			bigInt.SetUint64(uint64(v))
+		case uint32:
+			bigInt.SetUint64(uint64(v))
+		case uint64:
+			bigInt.SetUint64(v)
+		case string:
+			_, ok := bigInt.SetString(v, 10)
+			if !ok {
+				return nil, types.InvalidTypeError{}
+			}
+		default:
+			return data, nil
+		}
+
+		return bigInt, nil
+	}
+
+	if bi, ok := data.(*big.Int); ok {
+		switch to {
+		case reflect.TypeOf(0):
+			if FitsInNBitsSigned(strconv.IntSize, bi) {
+				return int(bi.Int64()), nil
+			}
+			return nil, types.InvalidTypeError{}
+		case reflect.TypeOf(int8(0)):
+			if FitsInNBitsSigned(8, bi) {
+				return int8(bi.Int64()), nil
+			}
+			return nil, types.InvalidTypeError{}
+		case reflect.TypeOf(int16(0)):
+			if FitsInNBitsSigned(16, bi) {
+				return int16(bi.Int64()), nil
+			}
+			return nil, types.InvalidTypeError{}
+		case reflect.TypeOf(int32(0)):
+			if FitsInNBitsSigned(32, bi) {
+				return int32(bi.Int64()), nil
+			}
+			return nil, types.InvalidTypeError{}
+		case reflect.TypeOf(int64(0)):
+			if FitsInNBitsSigned(64, bi) {
+				return bi.Int64(), nil
+			}
+			return nil, types.InvalidTypeError{}
+		case reflect.TypeOf(uint(0)):
+			if bi.Sign() >= 0 && bi.BitLen() <= strconv.IntSize {
+				return uint(bi.Uint64()), nil
+			}
+			return nil, types.InvalidTypeError{}
+		case reflect.TypeOf(uint8(0)):
+			if bi.Sign() >= 0 && bi.BitLen() <= 8 {
+				return uint8(bi.Uint64()), nil
+			}
+			return nil, types.InvalidTypeError{}
+		case reflect.TypeOf(uint16(0)):
+			if bi.Sign() >= 0 && bi.BitLen() <= 16 {
+				return uint16(bi.Uint64()), nil
+			}
+			return nil, types.InvalidTypeError{}
+		case reflect.TypeOf(uint32(0)):
+			if bi.Sign() >= 0 && bi.BitLen() <= 32 {
+				return uint32(bi.Uint64()), nil
+			}
+			return nil, types.InvalidTypeError{}
+		case reflect.TypeOf(uint64(0)):
+			if bi.Sign() >= 0 && bi.BitLen() <= 64 {
+				return bi.Uint64(), nil
+			}
+			return nil, types.InvalidTypeError{}
+		case reflect.TypeOf(""):
+			return bi.String(), nil
+		default:
+			return data, nil
+		}
+	}
+
+	return data, nil
+}
+
+func SliceToArrayVerifySizeHook(from reflect.Type, to reflect.Type, data any) (any, error) {
+	// By default, if the array is bigger it'll still work. (ie []int{1, 2, 3} => [4]int{} works with 0 at the end
+	// [2]int{} would not work. This seems to lenient, but can be discussed.
+	if from.Kind() == reflect.Slice && to.Kind() == reflect.Array {
+		slice := reflect.ValueOf(data)
+		if slice.Len() != to.Len() {
+			return nil, types.WrongNumberOfElements{}
+		}
+	}
+
+	return data, nil
+}
+
+func (m *mapDecoder) mapToItem(rawMap map[string]any, into any) error {
+	md := &mapstructure.Metadata{}
+	decoder, err := mapstructure.NewDecoder(&mapstructure.DecoderConfig{
+		// TODO add hook to verify number sizes. mapstructure seems to check -ve values for unsigned, but not other boundaries
+		DecodeHook: mapstructure.ComposeDecodeHookFunc(m.hooks...),
+		Metadata:   md,
+		Result:     into,
+	})
+
+	if err != nil {
+		return types.InvalidTypeError{}
+	}
+
+	if err = decoder.Decode(rawMap); err != nil {
+		return types.InvalidTypeError{}
+	}
+
+	return nil
+}