147 lines
4.1 KiB
Go
147 lines
4.1 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 (
|
|
"bytes"
|
|
"encoding/json"
|
|
"fmt"
|
|
"io"
|
|
)
|
|
|
|
// The ABI holds information about a contract's context and available
|
|
// invokable methods. It will allow you to type check function calls and
|
|
// packs data accordingly.
|
|
type ABI struct {
|
|
Constructor Method
|
|
Methods map[string]Method
|
|
Events map[string]Event
|
|
}
|
|
|
|
// JSON returns a parsed ABI interface and error if it failed.
|
|
func JSON(reader io.Reader) (ABI, error) {
|
|
dec := json.NewDecoder(reader)
|
|
|
|
var abi ABI
|
|
if err := dec.Decode(&abi); err != nil {
|
|
return ABI{}, err
|
|
}
|
|
|
|
return abi, nil
|
|
}
|
|
|
|
// Pack the given method name to conform the ABI. Method call's data
|
|
// will consist of method_id, args0, arg1, ... argN. Method id consists
|
|
// of 4 bytes and arguments are all 32 bytes.
|
|
// Method ids are created from the first 4 bytes of the hash of the
|
|
// methods string signature. (signature = baz(uint32,string32))
|
|
func (abi ABI) Pack(name string, args ...interface{}) ([]byte, error) {
|
|
// Fetch the ABI of the requested method
|
|
if name == "" {
|
|
// constructor
|
|
arguments, err := abi.Constructor.Inputs.Pack(args...)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
return arguments, nil
|
|
|
|
}
|
|
method, exist := abi.Methods[name]
|
|
if !exist {
|
|
return nil, fmt.Errorf("method '%s' not found", name)
|
|
}
|
|
|
|
arguments, err := method.Inputs.Pack(args...)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
// Pack up the method ID too if not a constructor and return
|
|
return append(method.Id(), arguments...), nil
|
|
}
|
|
|
|
// Unpack output in v according to the abi specification
|
|
func (abi ABI) Unpack(v interface{}, name string, output []byte) (err error) {
|
|
if len(output) == 0 {
|
|
return fmt.Errorf("abi: unmarshalling empty output")
|
|
}
|
|
// since there can't be naming collisions with contracts and events,
|
|
// we need to decide whether we're calling a method or an event
|
|
if method, ok := abi.Methods[name]; ok {
|
|
if len(output)%32 != 0 {
|
|
return fmt.Errorf("abi: improperly formatted output")
|
|
}
|
|
return method.Outputs.Unpack(v, output)
|
|
} else if event, ok := abi.Events[name]; ok {
|
|
return event.Inputs.Unpack(v, output)
|
|
}
|
|
return fmt.Errorf("abi: could not locate named method or event")
|
|
}
|
|
|
|
// UnmarshalJSON implements json.Unmarshaler interface
|
|
func (abi *ABI) UnmarshalJSON(data []byte) error {
|
|
var fields []struct {
|
|
Type string
|
|
Name string
|
|
Constant bool
|
|
Anonymous bool
|
|
Inputs []Argument
|
|
Outputs []Argument
|
|
}
|
|
|
|
if err := json.Unmarshal(data, &fields); err != nil {
|
|
return err
|
|
}
|
|
|
|
abi.Methods = make(map[string]Method)
|
|
abi.Events = make(map[string]Event)
|
|
for _, field := range fields {
|
|
switch field.Type {
|
|
case "constructor":
|
|
abi.Constructor = Method{
|
|
Inputs: field.Inputs,
|
|
}
|
|
// empty defaults to function according to the abi spec
|
|
case "function", "":
|
|
abi.Methods[field.Name] = Method{
|
|
Name: field.Name,
|
|
Const: field.Constant,
|
|
Inputs: field.Inputs,
|
|
Outputs: field.Outputs,
|
|
}
|
|
case "event":
|
|
abi.Events[field.Name] = Event{
|
|
Name: field.Name,
|
|
Anonymous: field.Anonymous,
|
|
Inputs: field.Inputs,
|
|
}
|
|
}
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// MethodById looks up a method by the 4-byte id
|
|
// returns nil if none found
|
|
func (abi *ABI) MethodById(sigdata []byte) (*Method, error) {
|
|
for _, method := range abi.Methods {
|
|
if bytes.Equal(method.Id(), sigdata[:4]) {
|
|
return &method, nil
|
|
}
|
|
}
|
|
return nil, fmt.Errorf("ABI spec does not contain method signature in data: 0x%x", sigdata[:4])
|
|
}
|