accounts/abi: redo unpacking logic into nice modular pieces

Signed-off-by: RJ Catalano <rj@monax.io>

accounts/abi/abi.go

@@ -21,7 +21,6 @@ import (
 	"fmt"
 	"io"
 	"reflect"
-	"strings"
 
 	"github.com/ethereum/go-ethereum/common"
 )
@@ -86,100 +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
 	}
 
-	if len(output)%32 != 0 {
-		return nil, fmt.Errorf("abi: improperly formatted output")
-	}
-
-	// 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 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)
-		}
-
+	var unpack unpacker
+	if method, ok := abi.Methods[name]; ok {
+		unpack = method
+	} else if event, ok := abi.Events[name]; ok {
+		unpack = event
 	} 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
-		}
+		return fmt.Errorf("abi: could not locate named method or event.")
 	}
 
-	return nil
+	if unpack.tupleReturn() {
+		return unpack.tupleUnpack(v, output)
+	}
+
+	return unpack.singleUnpack(v, output)
 }
 
 func (abi *ABI) UnmarshalJSON(data []byte) 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/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/unpack.go

@@ -25,6 +25,7 @@ import (
 	"github.com/ethereum/go-ethereum/common"
 )
 
+<<<<<<< HEAD
 // toGoSliceType parses the input and casts it to the proper slice defined by the ABI
 // argument in T.
 func toGoSlice(i int, t Argument, output []byte) (interface{}, error) {
@@ -115,6 +116,12 @@ func toGoSlice(i int, t Argument, output []byte) (interface{}, error) {
 
 	// return the interface
 	return refSlice.Interface(), nil
+=======
+type unpacker interface {
+	tupleUnpack(v interface{}, output []byte) error
+	singleUnpack(v interface{}, output []byte) error
+	tupleReturn() bool
+>>>>>>> 03ed394... accounts/abi: redo unpacking logic into nice modular pieces
 }
 
 func readInteger(kind reflect.Kind, b []byte) interface{} {
@@ -158,60 +165,141 @@ func readBool(word []byte) (bool, error) {
 	default:
 		return false, errBadBool
 	}
-
 }
 
+func readFunctionType(t Type, word []byte) (funcTy [24]byte, err error) {
+	if t.T != FunctionTy {
+		return [24]byte{}, fmt.Errorf("abi: invalid type in call to make function type byte array.")
+	}
+	if garbage := binary.BigEndian.Uint64(word[24:32]); garbage != 0 {
+		err = fmt.Errorf("abi: got improperly encoded function type, got %v", word)
+	} else {
+		copy(funcTy[:], word[0:24])
+	}
+	return
+}
+
+<<<<<<< HEAD
 // toGoType parses the input and casts it to the proper type defined by the ABI
 // argument in T.
 func toGoType(i int, t Argument, output []byte) (interface{}, error) {
 	// we need to treat slices differently
 	if (t.Type.IsSlice || t.Type.IsArray) && t.Type.T != BytesTy && t.Type.T != StringTy && t.Type.T != FixedBytesTy && t.Type.T != FunctionTy {
 		return toGoSlice(i, t, output)
+=======
+func readFixedBytes(t Type, word []byte) (interface{}, error) {
+	if t.T != FixedBytesTy {
+		return nil, fmt.Errorf("abi: invalid type in call to make fixed byte array.")
+>>>>>>> 03ed394... accounts/abi: redo unpacking logic into nice modular pieces
+	}
+	// convert
+	array := reflect.New(t.Type).Elem()
+
+	reflect.Copy(array, reflect.ValueOf(word[0:t.Size]))
+	return array, nil
+
+}
+
+func forEachUnpack(t Type, output []byte, start, size int) (interface{}, error) {
+	if start+32*size > len(output) {
+		return nil, fmt.Errorf("abi: cannot marshal in to go array: offset %d would go over slice boundary (len=%d)", len(output), start+32*size)
 	}
 
-	index := i * 32
+	// this value will become our slice or our array, depending on the type
+	var refSlice reflect.Value
+	slice := output[start : size*32]
+	if t.T == SliceTy {
+		// declare our slice
+		refSlice = reflect.MakeSlice(t.Type, size, size)
+	} else if t.T == ArrayTy {
+		// declare our array
+		refSlice = reflect.New(t.Type).Elem()
+	} else {
+		return nil, fmt.Errorf("abi: invalid type in array/slice unpacking stage")
+	}
+
+	for i, j := start, 0; j*32 < len(slice); i, j = i+32, j+1 {
+		inter, err := toGoType(i, *t.Elem, output)
+		if err != nil {
+			return nil, err
+		}
+		// append the item to our reflect slice
+		refSlice.Index(j).Set(reflect.ValueOf(inter))
+	}
+
+	// return the interface
+	return refSlice.Interface(), nil
+}
+
+// toGoType parses the input and casts it to the proper type defined by the ABI
+// argument in T.
+func toGoType(index int, t Type, output []byte) (interface{}, error) {
 	if index+32 > len(output) {
 		return nil, fmt.Errorf("abi: cannot marshal in to go type: length insufficient %d require %d", len(output), index+32)
 	}
 
 	// Parse the given index output and check whether we need to read
 	// a different offset and length based on the type (i.e. string, bytes)
-	var returnOutput []byte
-	switch t.Type.T {
-	case StringTy, BytesTy: // variable arrays are written at the end of the return bytes
-		// parse offset from which we should start reading
-		offset := int(binary.BigEndian.Uint64(output[index+24 : index+32]))
-		if offset+32 > len(output) {
-			return nil, fmt.Errorf("abi: cannot marshal in to go type: length insufficient %d require %d", len(output), offset+32)
-		}
-		// parse the size up until we should be reading
-		size := int(binary.BigEndian.Uint64(output[offset+24 : offset+32]))
-		if offset+32+size > len(output) {
-			return nil, fmt.Errorf("abi: cannot marshal in to go type: length insufficient %d require %d", len(output), offset+32+size)
-		}
+	var (
+		returnOutput []byte
+		i, j         int
+		err          error
+	)
 
-		// get the bytes for this return value
-		returnOutput = output[offset+32 : offset+32+size]
-	default:
+	if t.requiresLengthPrefix() {
+		i, j, err = lengthPrefixPointsTo(index, output)
+		if err != nil {
+			return nil, err
+		}
+	} else {
 		returnOutput = output[index : index+32]
 	}
-
-	// convert the bytes to whatever is specified by the ABI.
-	switch t.Type.T {
+	switch t.T {
+	case SliceTy:
+		return forEachUnpack(t, output, i, j)
+	case ArrayTy:
+		return forEachUnpack(t, output, i, t.Size)
+	case StringTy: // variable arrays are written at the end of the return bytes
+		return string(output[i : i+j]), nil
 	case IntTy, UintTy:
-		return readInteger(t.Type.Kind, returnOutput), nil
+		return readInteger(t.Kind, returnOutput), nil
 	case BoolTy:
 		return readBool(returnOutput)
 	case AddressTy:
 		return common.BytesToAddress(returnOutput), nil
 	case HashTy:
 		return common.BytesToHash(returnOutput), nil
-	case BytesTy, FixedBytesTy, FunctionTy:
+	case BytesTy:
 		return returnOutput, nil
-	case StringTy:
-		return string(returnOutput), nil
+	case FixedBytesTy:
+		return readFixedBytes(t, returnOutput)
+	case FunctionTy:
+		return readFunctionType(t, returnOutput)
+	default:
+		return nil, fmt.Errorf("abi: unknown type %v", t.T)
 	}
-	return nil, fmt.Errorf("abi: unknown type %v", t.Type.T)
 }
 
-// this needs a near complete redo
+// interprets a 32 byte slice as an offset and then determines which indice to look to decode the type.
+func lengthPrefixPointsTo(index int, output []byte) (start int, length int, err error) {
+	offset := int(binary.BigEndian.Uint64(output[index+24 : index+32]))
+	if offset+32 > len(output) {
+		return 0, 0, fmt.Errorf("abi: cannot marshal in to go slice: offset %d would go over slice boundary (len=%d)", len(output), offset+32)
+	}
+	length = int(binary.BigEndian.Uint64(output[offset+24 : offset+32]))
+	if offset+32+length > len(output) {
+		return 0, 0, fmt.Errorf("abi: cannot marshal in to go type: length insufficient %d require %d", len(output), offset+32+length)
+	}
+	start = offset + 32
+	return
+}
+
+func bytesAreProper(output []byte) error {
+	if len(output) == 0 {
+		return fmt.Errorf("abi: unmarshalling empty output")
+	} else if len(output)%32 != 0 {
+		return fmt.Errorf("abi: improperly formatted output")
+	} else {
+		return nil
+	}
+}