// Copyright 2015 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package abi
import (
"encoding/json"
"fmt"
"reflect"
"strings"
)
// Argument holds the name of the argument and the corresponding type.
// Types are used when packing and testing arguments.
type Argument struct {
Name string
Type Type
Indexed bool // indexed is only used by events
}
type Arguments []Argument
// UnmarshalJSON implements json.Unmarshaler interface
func (argument *Argument) UnmarshalJSON(data []byte) error {
var extarg struct {
Name string
Type string
Indexed bool
}
err := json.Unmarshal(data, &extarg)
if err != nil {
return fmt.Errorf("argument json err: %v", err)
}
argument.Type, err = NewType(extarg.Type)
if err != nil {
return err
}
argument.Name = extarg.Name
argument.Indexed = extarg.Indexed
return nil
}
// LengthNonIndexed returns the number of arguments when not counting 'indexed' ones. Only events
// can ever have 'indexed' arguments, it should always be false on arguments for method input/output
func (arguments Arguments) LengthNonIndexed() int {
out := 0
for _, arg := range arguments {
if !arg.Indexed {
out++
}
}
return out
}
// NonIndexed returns the arguments with indexed arguments filtered out
func (arguments Arguments) NonIndexed() Arguments {
var ret []Argument
for _, arg := range arguments {
if !arg.Indexed {
ret = append(ret, arg)
}
}
return ret
}
// isTuple returns true for non-atomic constructs, like (uint,uint) or uint[]
func (arguments Arguments) isTuple() bool {
return len(arguments) > 1
}
// Unpack performs the operation hexdata -> Go format
func (arguments Arguments) Unpack(v interface{}, data []byte) error {
// make sure the passed value is arguments pointer
if reflect.Ptr != reflect.ValueOf(v).Kind() {
return fmt.Errorf("abi: Unpack(non-pointer %T)", v)
}
marshalledValues, err := arguments.UnpackValues(data)
if err != nil {
return err
}
if arguments.isTuple() {
return arguments.unpackTuple(v, marshalledValues)
}
return arguments.unpackAtomic(v, marshalledValues)
}
func (arguments Arguments) unpackTuple(v interface{}, marshalledValues []interface{}) error {
var (
value = reflect.ValueOf(v).Elem()
typ = value.Type()
kind = value.Kind()
)
if err := requireUnpackKind(value, typ, kind, arguments); err != nil {
return err
}
// If the interface is a struct, get of abi->struct_field mapping
var abi2struct map[string]string
if kind == reflect.Struct {
var err error
abi2struct, err = mapAbiToStructFields(arguments, value)
if err != nil {
return err
}
}
for i, arg := range arguments.NonIndexed() {
reflectValue := reflect.ValueOf(marshalledValues[i])
switch kind {
case reflect.Struct:
if structField, ok := abi2struct[arg.Name]; ok {
if err := set(value.FieldByName(structField), reflectValue, arg); err != nil {
return err
}
}
case reflect.Slice, reflect.Array:
if value.Len() < i {
return fmt.Errorf("abi: insufficient number of arguments for unpack, want %d, got %d", len(arguments), value.Len())
}
v := value.Index(i)
if err := requireAssignable(v, reflectValue); err != nil {
return err
}
if err := set(v.Elem(), reflectValue, arg); err != nil {
return err
}
default:
return fmt.Errorf("abi:[2] cannot unmarshal tuple in to %v", typ)
}
}
return nil
}
// unpackAtomic unpacks ( hexdata -> go ) a single value
func (arguments Arguments) unpackAtomic(v interface{}, marshalledValues []interface{}) error {
if len(marshalledValues) != 1 {
return fmt.Errorf("abi: wrong length, expected single value, got %d", len(marshalledValues))
}
elem := reflect.ValueOf(v).Elem()
kind := elem.Kind()
reflectValue := reflect.ValueOf(marshalledValues[0])
var abi2struct map[string]string
if kind == reflect.Struct {
var err error
if abi2struct, err = mapAbiToStructFields(arguments, elem); err != nil {
return err
}
arg := arguments.NonIndexed()[0]
if structField, ok := abi2struct[arg.Name]; ok {
return set(elem.FieldByName(structField), reflectValue, arg)
}
return nil
}
return set(elem, reflectValue, arguments.NonIndexed()[0])
}
// Computes the full size of an array;
// i.e. counting nested arrays, which count towards size for unpacking.
func getArraySize(arr *Type) int {
size := arr.Size
// Arrays can be nested, with each element being the same size
arr = arr.Elem
for arr.T == ArrayTy {
// Keep multiplying by elem.Size while the elem is an array.
size *= arr.Size
arr = arr.Elem
}
// Now we have the full array size, including its children.
return size
}
// UnpackValues can be used to unpack ABI-encoded hexdata according to the ABI-specification,
// without supplying a struct to unpack into. Instead, this method returns a list containing the
// values. An atomic argument will be a list with one element.
func (arguments Arguments) UnpackValues(data []byte) ([]interface{}, error) {
retval := make([]interface{}, 0, arguments.LengthNonIndexed())
virtualArgs := 0
for index, arg := range arguments.NonIndexed() {
marshalledValue, err := toGoType((index+virtualArgs)*32, arg.Type, data)
if arg.Type.T == ArrayTy && (*arg.Type.Elem).T != StringTy {
// If we have a static array, like [3]uint256, these are coded as
// just like uint256,uint256,uint256.
// This means that we need to add two 'virtual' arguments when
// we count the index from now on.
//
// Array values nested multiple levels deep are also encoded inline:
// [2][3]uint256: uint256,uint256,uint256,uint256,uint256,uint256
//
// Calculate the full array size to get the correct offset for the next argument.
// Decrement it by 1, as the normal index increment is still applied.
virtualArgs += getArraySize(&arg.Type) - 1
}
if err != nil {
return nil, err
}
retval = append(retval, marshalledValue)
}
return retval, nil
}
// PackValues performs the operation Go format -> Hexdata
// It is the semantic opposite of UnpackValues
func (arguments Arguments) PackValues(args []interface{}) ([]byte, error) {
return arguments.Pack(args...)
}
// Pack performs the operation Go format -> Hexdata
func (arguments Arguments) Pack(args ...interface{}) ([]byte, error) {
// Make sure arguments match up and pack them
abiArgs := arguments
if len(args) != len(abiArgs) {
return nil, fmt.Errorf("argument count mismatch: %d for %d", len(args), len(abiArgs))
}
// variable input is the output appended at the end of packed
// output. This is used for strings and bytes types input.
var variableInput []byte
// input offset is the bytes offset for packed output
inputOffset := 0
for _, abiArg := range abiArgs {
inputOffset += getDynamicTypeOffset(abiArg.Type)
}
var ret []byte
for i, a := range args {
input := abiArgs[i]
// pack the input
packed, err := input.Type.pack(reflect.ValueOf(a))
if err != nil {
return nil, err
}
// check for dynamic types
if isDynamicType(input.Type) {
// set the offset
ret = append(ret, packNum(reflect.ValueOf(inputOffset))...)
// calculate next offset
inputOffset += len(packed)
// append to variable input
variableInput = append(variableInput, packed...)
} else {
// append the packed value to the input
ret = append(ret, packed...)
}
}
// append the variable input at the end of the packed input
ret = append(ret, variableInput...)
return ret, nil
}
// capitalise makes the first character of a string upper case, also removing any
// prefixing underscores from the variable names.
func capitalise(input string) string {
for len(input) > 0 && input[0] == '_' {
input = input[1:]
}
if len(input) == 0 {
return ""
}
return strings.ToUpper(input[:1]) + input[1:]
}
