plugeth/accounts/abi/argument.go
protolambda 0b814d32f8 accounts/abi: Abi binding support for nested arrays, fixes #15648, including nested array unpack fix (#15676)
* accounts/abi/bind: support for multi-dim arrays

Also:
- reduce usage of regexes a bit.
- fix minor Java syntax problems

Fixes #15648

* accounts/abi/bind: Add some more documentation

* accounts/abi/bind: Improve code readability

* accounts/abi: bugfix for unpacking nested arrays

The code previously assumed the arrays/slices were always 1 level
deep. While the packing supports nested arrays (!!!).

The current code for unpacking doesn't return the "consumed" length, so
this fix had to work around that by calculating it (i.e. packing and
 getting resulting length) after the unpacking of the array element.
It's far from ideal, but unpacking behaviour is fixed now.

* accounts/abi: Fix unpacking of nested arrays

Removed the temporary workaround of packing to calculate size, which was
incorrect for slice-like types anyway.
Full size of nested arrays is used now.

* accounts/abi: deeply nested array unpack test

Test unpacking of an array nested more than one level.

* accounts/abi: Add deeply nested array pack test

Same as the deep nested array unpack test, but the other way around.

* accounts/abi/bind: deeply nested arrays bind test

Test the usage of bindings that were generated
for methods with multi-dimensional (and not
just a single extra dimension, like foo[2][3])
array arguments and returns.

edit: trigger rebuild, CI failed to fetch linter module.

* accounts/abi/bind: improve array binding

wrapArray uses a regex now, and arrayBindingJava is improved.

* accounts/abi: Improve naming of element size func

The full step size for unpacking an array
 is now retrieved with "getFullElemSize".

* accounts/abi: support nested nested array args

Previously, the code only considered the outer-size of the array,
ignoring the size of the contents. This was fine for most types,
but nested arrays are packed directly into it, and count towards
the total size. This resulted in arguments following a nested
array to replicate some of the binary contents of the array.

The fix: for arrays, calculate their complete contents size:
 count the arg.Type.Elem.Size when Elem is an Array, and
 repeat when their child is an array too, etc.
The count is the number of 32 byte elements, similar to how it
 previously counted, but nested.

* accounts/abi: Test deep nested arr multi-arguments

Arguments with a deeply nested array should not cause the next arguments
to be read from the wrong position.
2018-03-04 23:24:17 +01:00

281 lines
8.4 KiB
Go

// 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 output interface is a struct, make sure names don't collide
if kind == reflect.Struct {
exists := make(map[string]bool)
for _, arg := range arguments {
field := capitalise(arg.Name)
if field == "" {
return fmt.Errorf("abi: purely underscored output cannot unpack to struct")
}
if exists[field] {
return fmt.Errorf("abi: multiple outputs mapping to the same struct field '%s'", field)
}
exists[field] = true
}
}
for i, arg := range arguments.NonIndexed() {
reflectValue := reflect.ValueOf(marshalledValues[i])
switch kind {
case reflect.Struct:
name := capitalise(arg.Name)
for j := 0; j < typ.NumField(); j++ {
// TODO read tags: `abi:"fieldName"`
if typ.Field(j).Name == name {
if err := set(value.Field(j), 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()
reflectValue := reflect.ValueOf(marshalledValues[0])
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 {
// 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 {
if abiArg.Type.T == ArrayTy {
inputOffset += 32 * abiArg.Type.Size
} else {
inputOffset += 32
}
}
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 a slice type (string, bytes, slice)
if input.Type.requiresLengthPrefix() {
// calculate the offset
offset := inputOffset + len(variableInput)
// set the offset
ret = append(ret, packNum(reflect.ValueOf(offset))...)
// Append the packed output to the variable input. The variable input
// will be appended at the end of the 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:]
}