Create a codec entry with from args, allowing us to do type checking and to have structs to use with abi.Arguments's Pack function

core/services/relay/evm/codec_entry.go

@@ -0,0 +1,132 @@
+package evm
+
+import (
+	"reflect"
+	"strings"
+
+	"github.com/ethereum/go-ethereum/accounts/abi"
+
+	commontypes "github.com/smartcontractkit/chainlink-common/pkg/types"
+
+	"github.com/smartcontractkit/chainlink/v2/core/services/relay/evm/types"
+)
+
+type CodecEntry struct {
+	Args        abi.Arguments
+	checkedType reflect.Type
+	nativeType  reflect.Type
+}
+
+func (info *CodecEntry) Init() error {
+	if info.checkedType != nil {
+		return nil
+	}
+
+	args := UnwrapArgs(info.Args)
+	argLen := len(args)
+	native := make([]reflect.StructField, argLen)
+	checked := make([]reflect.StructField, argLen)
+
+	if len(args) == 1 && args[0].Name == "" {
+		nativeArg, checkedArg, err := getNativeAndCheckedTypes(&args[0].Type)
+		if err != nil {
+			return err
+		}
+		info.nativeType = nativeArg
+		info.checkedType = checkedArg
+		return nil
+	}
+
+	for i, arg := range args {
+		tmp := arg.Type
+		nativeArg, checkedArg, err := getNativeAndCheckedTypes(&tmp)
+		if err != nil {
+			return err
+		}
+		tag := reflect.StructTag(`json:"` + arg.Name + `"`)
+		name := strings.ToUpper(arg.Name[:1]) + arg.Name[1:]
+		native[i] = reflect.StructField{Name: name, Type: nativeArg, Tag: tag}
+		checked[i] = reflect.StructField{Name: name, Type: checkedArg, Tag: tag}
+	}
+
+	info.nativeType = reflect.StructOf(native)
+	info.checkedType = reflect.StructOf(checked)
+	return nil
+}
+
+func UnwrapArgs(args abi.Arguments) abi.Arguments {
+	// Unwrap an unnamed tuple so that callers don't need to wrap it
+	// Eg: If you have struct Foo { ... } and return an unnamed Foo, you should be able ot decode to a go Foo{} directly
+	if len(args) != 1 || args[0].Name != "" {
+		return args
+	}
+
+	elms := args[0].Type.TupleElems
+	if len(elms) != 0 {
+		names := args[0].Type.TupleRawNames
+		args = make(abi.Arguments, len(elms))
+		for i, elm := range elms {
+			args[i] = abi.Argument{
+				Name: names[i],
+				Type: *elm,
+			}
+		}
+	}
+	return args
+}
+
+func getNativeAndCheckedTypes(curType *abi.Type) (reflect.Type, reflect.Type, error) {
+	converter := func(t reflect.Type) reflect.Type { return t }
+	for curType.Elem != nil {
+		prior := converter
+		switch curType.GetType().Kind() {
+		case reflect.Slice:
+			converter = func(t reflect.Type) reflect.Type {
+				return prior(reflect.SliceOf(t))
+			}
+			curType = curType.Elem
+		case reflect.Array:
+			tmp := curType
+			converter = func(t reflect.Type) reflect.Type {
+				return prior(reflect.ArrayOf(tmp.Size, t))
+			}
+			curType = curType.Elem
+		default:
+			return nil, nil, commontypes.ErrInvalidType
+		}
+	}
+	base, ok := types.GetType(curType.String())
+	if ok {
+		return converter(base.Native), converter(base.Checked), nil
+	}
+
+	return createTupleType(curType, converter)
+}
+
+func createTupleType(curType *abi.Type, converter func(reflect.Type) reflect.Type) (reflect.Type, reflect.Type, error) {
+	if len(curType.TupleElems) == 0 {
+		return curType.TupleType, curType.TupleType, nil
+	}
+
+	// Create native type ourselves to assure that it'll always have the exact memory layout of checked types
+	// Otherwise, the "unsafe" casting that will be done to convert from checked to native won't be safe.
+	// At the time of writing, the way the TupleType is built it will be the same, but I don't want to rely on that
+	// If they ever add private fields for internal tracking
+	// or anything it would break us if we don't build the native type.
+	// As an example of how it could possibly change in the future, I've seen struct{}
+	// added with tags to the top of generated structs to allow metadata exploration.
+	nativeFields := make([]reflect.StructField, len(curType.TupleElems))
+	checkedFields := make([]reflect.StructField, len(curType.TupleElems))
+	for i, elm := range curType.TupleElems {
+		name := curType.TupleRawNames[i]
+		nativeFields[i].Name = name
+		checkedFields[i].Name = name
+		nativeArgType, checkedArgType, err := getNativeAndCheckedTypes(elm)
+		if err != nil {
+			return nil, nil, err
+		}
+		nativeFields[i].Type = nativeArgType
+		checkedFields[i].Type = checkedArgType
+	}
+	return converter(reflect.StructOf(nativeFields)), converter(reflect.StructOf(checkedFields)), nil
+}

core/services/relay/evm/codec_entry_test.go

@@ -0,0 +1,139 @@
+package evm
+
+import (
+	"math/big"
+	"reflect"
+	"testing"
+
+	"github.com/ethereum/go-ethereum/accounts/abi"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	commontypes "github.com/smartcontractkit/chainlink-common/pkg/types"
+
+	"github.com/smartcontractkit/chainlink/v2/core/services/relay/evm/types"
+)
+
+func TestCodecEntry(t *testing.T) {
+	t.Run("basic types", func(t *testing.T) {
+		type1, err := abi.NewType("uint16", "", []abi.ArgumentMarshaling{})
+		require.NoError(t, err)
+		type2, err := abi.NewType("string", "", []abi.ArgumentMarshaling{})
+		require.NoError(t, err)
+		type3, err := abi.NewType("uint24", "", []abi.ArgumentMarshaling{})
+		require.NoError(t, err)
+		type4, err := abi.NewType("int24", "", []abi.ArgumentMarshaling{})
+		require.NoError(t, err)
+		entry := CodecEntry{
+			Args: abi.Arguments{
+				{Name: "Field1", Type: type1},
+				{Name: "Field2", Type: type2},
+				{Name: "Field3", Type: type3},
+				{Name: "Field4", Type: type4},
+			},
+		}
+		require.NoError(t, entry.Init())
+		native := reflect.New(entry.nativeType)
+		iNative := reflect.Indirect(native)
+		iNative.FieldByName("Field1").Set(reflect.ValueOf(uint16(2)))
+		iNative.FieldByName("Field2").Set(reflect.ValueOf("any string"))
+		iNative.FieldByName("Field3").Set(reflect.ValueOf(big.NewInt( /*2^24 - 1*/ 16777215)))
+		iNative.FieldByName("Field4").Set(reflect.ValueOf(big.NewInt( /*2^23 - 1*/ 8388607)))
+		// native and checked point to the same item, even though they have different "types"
+		// they have the same memory layout so this is safe per unsafe casting rules, see unsafe.Pointer for details
+		checked := reflect.NewAt(entry.checkedType, native.UnsafePointer())
+		iChecked := reflect.Indirect(checked)
+		checkedField := iChecked.FieldByName("Field3").Interface()
+
+		sbi, ok := checkedField.(types.SizedBigInt)
+		require.True(t, ok)
+		assert.NoError(t, sbi.Verify())
+		bi, ok := iNative.FieldByName("Field3").Interface().(*big.Int)
+		require.True(t, ok)
+		bi.Add(bi, big.NewInt(1))
+		assert.IsType(t, commontypes.ErrInvalidType, sbi.Verify())
+		bi, ok = iNative.FieldByName("Field4").Interface().(*big.Int)
+		require.True(t, ok)
+		bi.Add(bi, big.NewInt(1))
+		assert.IsType(t, commontypes.ErrInvalidType, sbi.Verify())
+	})
+
+	t.Run("tuples", func(t *testing.T) {
+		type1, err := abi.NewType("uint16", "", []abi.ArgumentMarshaling{})
+		require.NoError(t, err)
+		tupleType, err := abi.NewType("tuple", "", []abi.ArgumentMarshaling{
+			{Name: "Field3", Type: "uint24"},
+			{Name: "Field4", Type: "int24"},
+		})
+		require.NoError(t, err)
+		entry := CodecEntry{
+			Args: abi.Arguments{
+				{Name: "Field1", Type: type1},
+				{Name: "Field2", Type: tupleType},
+			},
+		}
+		require.NoError(t, entry.Init())
+		native := reflect.New(entry.nativeType)
+		iNative := reflect.Indirect(native)
+		iNative.FieldByName("Field1").Set(reflect.ValueOf(uint16(2)))
+		f2 := iNative.FieldByName("Field2")
+		f2.FieldByName("Field3").Set(reflect.ValueOf(big.NewInt( /*2^24 - 1*/ 16777215)))
+		f2.FieldByName("Field4").Set(reflect.ValueOf(big.NewInt( /*2^23 - 1*/ 8388607)))
+		// native and checked point to the same item, even though they have different "types"
+		// they have the same memory layout so this is safe per unsafe casting rules, see unsafe.Pointer for details
+		checked := reflect.NewAt(entry.checkedType, native.UnsafePointer())
+		tuple := reflect.Indirect(checked).FieldByName("Field2")
+		checkedField := tuple.FieldByName("Field3").Interface()
+
+		sbi, ok := checkedField.(types.SizedBigInt)
+		require.True(t, ok)
+		assert.NoError(t, sbi.Verify())
+		bi, ok := f2.FieldByName("Field3").Interface().(*big.Int)
+		require.True(t, ok)
+		bi.Add(bi, big.NewInt(1))
+		assert.IsType(t, commontypes.ErrInvalidType, sbi.Verify())
+		bi, ok = f2.FieldByName("Field4").Interface().(*big.Int)
+		require.True(t, ok)
+		bi.Add(bi, big.NewInt(1))
+		assert.IsType(t, commontypes.ErrInvalidType, sbi.Verify())
+	})
+
+	t.Run("unwrapped types", func(t *testing.T) {
+		// This exists to allow you to decode single returned values without naming the parameter
+		wrappedTuple, err := abi.NewType("tuple", "", []abi.ArgumentMarshaling{
+			{Name: "Field1", Type: "int16"},
+		})
+		require.NoError(t, err)
+		entry := CodecEntry{
+			Args: abi.Arguments{{Name: "", Type: wrappedTuple}},
+		}
+		require.NoError(t, entry.Init())
+		native := reflect.New(entry.nativeType)
+		iNative := reflect.Indirect(native)
+		iNative.FieldByName("Field1").Set(reflect.ValueOf(int16(2)))
+	})
+
+	t.Run("slice types", func(t *testing.T) {
+		type1, err := abi.NewType("int16[]", "", []abi.ArgumentMarshaling{})
+		require.NoError(t, err)
+		entry := CodecEntry{
+			Args: abi.Arguments{{Name: "Field1", Type: type1}},
+		}
+		require.NoError(t, entry.Init())
+		native := reflect.New(entry.nativeType)
+		iNative := reflect.Indirect(native)
+		iNative.FieldByName("Field1").Set(reflect.ValueOf([]int16{2, 3}))
+	})
+
+	t.Run("array types", func(t *testing.T) {
+		type1, err := abi.NewType("int16[3]", "", []abi.ArgumentMarshaling{})
+		require.NoError(t, err)
+		entry := CodecEntry{
+			Args: abi.Arguments{{Name: "Field1", Type: type1}},
+		}
+		require.NoError(t, entry.Init())
+		native := reflect.New(entry.nativeType)
+		iNative := reflect.Indirect(native)
+		iNative.FieldByName("Field1").Set(reflect.ValueOf([3]int16{2, 3, 30}))
+	})
+}