accounts/abi: Better Array/Slice Handling

accounts/abi/abi.go

@@ -21,7 +21,6 @@ import (
 	"fmt"
 	"io"
 	"reflect"
-	"strings"
 
 	"github.com/ethereum/go-ethereum/common"
 )
@@ -86,96 +85,26 @@ var (
 )
 
 // Unpack output in v according to the abi specification
-func (abi ABI) Unpack(v interface{}, name string, output []byte) error {
-	var method = abi.Methods[name]
+func (abi ABI) Unpack(v interface{}, name string, output []byte) (err error) {
 
-	if len(output) == 0 {
-		return fmt.Errorf("abi: unmarshalling empty output")
+	if err = bytesAreProper(output); err != nil {
+		return err
 	}
 
-	// make sure the passed value is a pointer
-	valueOf := reflect.ValueOf(v)
-	if reflect.Ptr != valueOf.Kind() {
-		return fmt.Errorf("abi: Unpack(non-pointer %T)", v)
+	var unpack unpacker
+	if method, ok := abi.Methods[name]; ok {
+		unpack = method
+	} else if event, ok := abi.Events[name]; ok {
+		unpack = event
+	} else {
+		return fmt.Errorf("abi: could not locate named method or event.")
 	}
 
-	var (
-		value = valueOf.Elem()
-		typ   = value.Type()
-	)
-
-	if len(method.Outputs) > 1 {
-		switch value.Kind() {
-		// struct will match named return values to the struct's field
-		// names
-		case reflect.Struct:
-			for i := 0; i < len(method.Outputs); i++ {
-				marshalledValue, err := toGoType(i, method.Outputs[i], output)
-				if err != nil {
-					return err
-				}
-				reflectValue := reflect.ValueOf(marshalledValue)
-
-				for j := 0; j < typ.NumField(); j++ {
-					field := typ.Field(j)
-					// TODO read tags: `abi:"fieldName"`
-					if field.Name == strings.ToUpper(method.Outputs[i].Name[:1])+method.Outputs[i].Name[1:] {
-						if err := set(value.Field(j), reflectValue, method.Outputs[i]); err != nil {
-							return err
-						}
-					}
-				}
-			}
-		case reflect.Slice:
-			if !value.Type().AssignableTo(r_interSlice) {
-				return fmt.Errorf("abi: cannot marshal tuple in to slice %T (only []interface{} is supported)", v)
-			}
-
-			// if the slice already contains values, set those instead of the interface slice itself.
-			if value.Len() > 0 {
-				if len(method.Outputs) > value.Len() {
-					return fmt.Errorf("abi: cannot marshal in to slices of unequal size (require: %v, got: %v)", len(method.Outputs), value.Len())
-				}
-
-				for i := 0; i < len(method.Outputs); i++ {
-					marshalledValue, err := toGoType(i, method.Outputs[i], output)
-					if err != nil {
-						return err
-					}
-					reflectValue := reflect.ValueOf(marshalledValue)
-					if err := set(value.Index(i).Elem(), reflectValue, method.Outputs[i]); err != nil {
-						return err
-					}
-				}
-				return nil
-			}
-
-			// create a new slice and start appending the unmarshalled
-			// values to the new interface slice.
-			z := reflect.MakeSlice(typ, 0, len(method.Outputs))
-			for i := 0; i < len(method.Outputs); i++ {
-				marshalledValue, err := toGoType(i, method.Outputs[i], output)
-				if err != nil {
-					return err
-				}
-				z = reflect.Append(z, reflect.ValueOf(marshalledValue))
-			}
-			value.Set(z)
-		default:
-			return fmt.Errorf("abi: cannot unmarshal tuple in to %v", typ)
-		}
-
-	} else {
-		marshalledValue, err := toGoType(0, method.Outputs[0], output)
-		if err != nil {
-			return err
-		}
-		if err := set(value, reflect.ValueOf(marshalledValue), method.Outputs[0]); err != nil {
-			return err
-		}
+	if unpack.tupleReturn() {
+		return unpack.tupleUnpack(v, output)
 	}
 
-	return nil
+	return unpack.singleUnpack(v, output)
 }
 
 func (abi *ABI) UnmarshalJSON(data []byte) error {

accounts/abi/abi_test.go

@@ -191,7 +191,7 @@ func TestMethodSignature(t *testing.T) {
 		t.Errorf("expected ids to match %x != %x", m.Id(), idexp)
 	}
 
-	uintt, _ := NewType("uint")
+	uintt, _ := NewType("uint256")
 	m = Method{"foo", false, []Argument{{"bar", uintt, false}}, nil}
 	exp = "foo(uint256)"
 	if m.Sig() != exp {

accounts/abi/error.go

@@ -39,38 +39,43 @@ func formatSliceString(kind reflect.Kind, sliceSize int) string {
 // type in t.
 func sliceTypeCheck(t Type, val reflect.Value) error {
 	if val.Kind() != reflect.Slice && val.Kind() != reflect.Array {
-		return typeErr(formatSliceString(t.Kind, t.SliceSize), val.Type())
+		return typeErr(formatSliceString(t.Kind, t.Size), val.Type())
 	}
-	if t.IsArray && val.Len() != t.SliceSize {
-		return typeErr(formatSliceString(t.Elem.Kind, t.SliceSize), formatSliceString(val.Type().Elem().Kind(), val.Len()))
+
+	if t.T == ArrayTy && val.Len() != t.Size {
+		return typeErr(formatSliceString(t.Elem.Kind, t.Size), formatSliceString(val.Type().Elem().Kind(), val.Len()))
 	}
 
-	if t.Elem.IsSlice {
+	if t.Elem.T == SliceTy {
 		if val.Len() > 0 {
 			return sliceTypeCheck(*t.Elem, val.Index(0))
 		}
-	} else if t.Elem.IsArray {
+	} else if t.Elem.T == ArrayTy {
 		return sliceTypeCheck(*t.Elem, val.Index(0))
 	}
 
 	if elemKind := val.Type().Elem().Kind(); elemKind != t.Elem.Kind {
-		return typeErr(formatSliceString(t.Elem.Kind, t.SliceSize), val.Type())
+		return typeErr(formatSliceString(t.Elem.Kind, t.Size), val.Type())
 	}
 	return nil
 }
 
 // typeCheck checks that the given reflection value can be assigned to the reflection
 // type in t.
 func typeCheck(t Type, value reflect.Value) error {
-	if t.IsSlice || t.IsArray {
+	if t.T == SliceTy || t.T == ArrayTy {
 		return sliceTypeCheck(t, value)
 	}
 
 	// Check base type validity. Element types will be checked later on.
 	if t.Kind != value.Kind() {
 		return typeErr(t.Kind, value.Kind())
+	} else if t.T == FixedBytesTy && t.Size != value.Len() {
+		return typeErr(t.Type, value.Type())
+	} else {
+		return nil
 	}
-	return nil
+
 }
 
 // varErr returns a formatted error.

accounts/abi/event.go

@@ -18,6 +18,7 @@ package abi
 
 import (
 	"fmt"
+	"reflect"
 	"strings"
 
 	"github.com/ethereum/go-ethereum/common"
@@ -44,3 +45,72 @@ func (e Event) Id() common.Hash {
 	}
 	return common.BytesToHash(crypto.Keccak256([]byte(fmt.Sprintf("%v(%v)", e.Name, strings.Join(types, ",")))))
 }
+
+func (e Event) tupleUnpack(v interface{}, output []byte) error {
+	// make sure the passed value is a pointer
+	valueOf := reflect.ValueOf(v)
+	if reflect.Ptr != valueOf.Kind() {
+		return fmt.Errorf("abi: Unpack(non-pointer %T)", v)
+	}
+
+	var (
+		value = valueOf.Elem()
+		typ   = value.Type()
+	)
+
+	if value.Kind() != reflect.Struct {
+		return fmt.Errorf("abi: cannot unmarshal tuple in to %v", typ)
+	}
+
+	j := 0
+	for i := 0; i < len(e.Inputs); i++ {
+		input := e.Inputs[i]
+		if input.Indexed {
+			// can't read, continue
+			continue
+		} else if input.Type.T == ArrayTy {
+			// need to move this up because they read sequentially
+			j += input.Type.Size
+		}
+		marshalledValue, err := toGoType((i+j)*32, input.Type, output)
+		if err != nil {
+			return err
+		}
+		reflectValue := reflect.ValueOf(marshalledValue)
+		for j := 0; j < typ.NumField(); j++ {
+			field := typ.Field(j)
+			// TODO read tags: `abi:"fieldName"`
+			if field.Name == strings.ToUpper(e.Inputs[i].Name[:1])+e.Inputs[i].Name[1:] {
+				if err := set(value.Field(j), reflectValue, e.Inputs[i]); err != nil {
+					return err
+				}
+			}
+		}
+	}
+	return nil
+}
+
+func (e Event) tupleReturn() bool { return len(e.Inputs) > 1 }
+
+func (e Event) singleUnpack(v interface{}, output []byte) error {
+	// make sure the passed value is a pointer
+	valueOf := reflect.ValueOf(v)
+	if reflect.Ptr != valueOf.Kind() {
+		return fmt.Errorf("abi: Unpack(non-pointer %T)", v)
+	}
+
+	if e.Inputs[0].Indexed {
+		return fmt.Errorf("abi: attempting to unpack indexed variable into element.")
+	}
+
+	value := valueOf.Elem()
+
+	marshalledValue, err := toGoType(0, e.Inputs[0].Type, output)
+	if err != nil {
+		return err
+	}
+	if err := set(value, reflect.ValueOf(marshalledValue), e.Inputs[0]); err != nil {
+		return err
+	}
+	return nil
+}

accounts/abi/event_test.go

@@ -31,7 +31,7 @@ func TestEventId(t *testing.T) {
 	}{
 		{
 			definition: `[
-			{ "type" : "event", "name" : "balance", "inputs": [{ "name" : "in", "type": "uint" }] },
+			{ "type" : "event", "name" : "balance", "inputs": [{ "name" : "in", "type": "uint256" }] },
 			{ "type" : "event", "name" : "check", "inputs": [{ "name" : "t", "type": "address" }, { "name": "b", "type": "uint256" }] }
 			]`,
 			expectations: map[string]common.Hash{

accounts/abi/method.go

@@ -77,6 +77,68 @@ func (method Method) pack(args ...interface{}) ([]byte, error) {
 	return ret, nil
 }
 
+func (method Method) tupleUnpack(v interface{}, output []byte) error {
+	// make sure the passed value is a pointer
+	valueOf := reflect.ValueOf(v)
+	if reflect.Ptr != valueOf.Kind() {
+		return fmt.Errorf("abi: Unpack(non-pointer %T)", v)
+	}
+
+	var (
+		value = valueOf.Elem()
+		typ   = value.Type()
+	)
+
+	if value.Kind() != reflect.Struct {
+		return fmt.Errorf("abi: cannot unmarshal tuple in to %v", typ)
+	}
+
+	j := 0
+	for i := 0; i < len(method.Outputs); i++ {
+		toUnpack := method.Outputs[i]
+		if toUnpack.Type.T == ArrayTy {
+			// need to move this up because they read sequentially
+			j += toUnpack.Type.Size
+		}
+		marshalledValue, err := toGoType((i+j)*32, toUnpack.Type, output)
+		if err != nil {
+			return err
+		}
+		reflectValue := reflect.ValueOf(marshalledValue)
+		for j := 0; j < typ.NumField(); j++ {
+			field := typ.Field(j)
+			// TODO read tags: `abi:"fieldName"`
+			if field.Name == strings.ToUpper(method.Outputs[i].Name[:1])+method.Outputs[i].Name[1:] {
+				if err := set(value.Field(j), reflectValue, method.Outputs[i]); err != nil {
+					return err
+				}
+			}
+		}
+	}
+	return nil
+}
+
+func (method Method) tupleReturn() bool { return len(method.Outputs) > 1 }
+
+func (method Method) singleUnpack(v interface{}, output []byte) error {
+	// make sure the passed value is a pointer
+	valueOf := reflect.ValueOf(v)
+	if reflect.Ptr != valueOf.Kind() {
+		return fmt.Errorf("abi: Unpack(non-pointer %T)", v)
+	}
+
+	value := valueOf.Elem()
+
+	marshalledValue, err := toGoType(0, method.Outputs[0].Type, output)
+	if err != nil {
+		return err
+	}
+	if err := set(value, reflect.ValueOf(marshalledValue), method.Outputs[0]); err != nil {
+		return err
+	}
+	return nil
+}
+
 // Sig returns the methods string signature according to the ABI spec.
 //
 // Example

accounts/abi/numbers.go

@@ -25,22 +25,22 @@ import (
 )
 
 var (
-	big_t     = reflect.TypeOf(big.Int{})
-	ubig_t    = reflect.TypeOf(big.Int{})
-	byte_t    = reflect.TypeOf(byte(0))
-	byte_ts   = reflect.TypeOf([]byte(nil))
-	uint_t    = reflect.TypeOf(uint(0))
-	uint8_t   = reflect.TypeOf(uint8(0))
-	uint16_t  = reflect.TypeOf(uint16(0))
-	uint32_t  = reflect.TypeOf(uint32(0))
-	uint64_t  = reflect.TypeOf(uint64(0))
-	int_t     = reflect.TypeOf(int(0))
-	int8_t    = reflect.TypeOf(int8(0))
-	int16_t   = reflect.TypeOf(int16(0))
-	int32_t   = reflect.TypeOf(int32(0))
-	int64_t   = reflect.TypeOf(int64(0))
-	hash_t    = reflect.TypeOf(common.Hash{})
-	address_t = reflect.TypeOf(common.Address{})
+	big_t      = reflect.TypeOf(&big.Int{})
+	derefbig_t = reflect.TypeOf(big.Int{})
+	byte_t     = reflect.TypeOf(byte(0))
+	byte_ts    = reflect.TypeOf([]byte(nil))
+	uint_t     = reflect.TypeOf(uint(0))
+	uint8_t    = reflect.TypeOf(uint8(0))
+	uint16_t   = reflect.TypeOf(uint16(0))
+	uint32_t   = reflect.TypeOf(uint32(0))
+	uint64_t   = reflect.TypeOf(uint64(0))
+	int_t      = reflect.TypeOf(int(0))
+	int8_t     = reflect.TypeOf(int8(0))
+	int16_t    = reflect.TypeOf(int16(0))
+	int32_t    = reflect.TypeOf(int32(0))
+	int64_t    = reflect.TypeOf(int64(0))
+	hash_t     = reflect.TypeOf(common.Hash{})
+	address_t  = reflect.TypeOf(common.Address{})
 
 	uint_ts   = reflect.TypeOf([]uint(nil))
 	uint8_ts  = reflect.TypeOf([]uint8(nil))

accounts/abi/pack_test.go

@@ -322,12 +322,12 @@ func TestPack(t *testing.T) {
 	} {
 		typ, err := NewType(test.typ)
 		if err != nil {
-			t.Fatal("unexpected parse error:", err)
+			t.Fatalf("%v failed. Unexpected parse error: %v", i, err)
 		}
 
 		output, err := typ.pack(reflect.ValueOf(test.input))
 		if err != nil {
-			t.Fatal("unexpected pack error:", err)
+			t.Fatalf("%v failed. Unexpected pack error: %v", i, err)
 		}
 
 		if !bytes.Equal(output, test.output) {