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