305 lines
9.0 KiB
Go
305 lines
9.0 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"
|
|
"io"
|
|
"reflect"
|
|
"strings"
|
|
|
|
"github.com/ethereum/go-ethereum/common"
|
|
)
|
|
|
|
// Executer is an executer method for performing state executions. It takes one
|
|
// argument which is the input data and expects output data to be returned as
|
|
// multiple 32 byte word length concatenated slice
|
|
type Executer func(datain []byte) []byte
|
|
|
|
// 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 {
|
|
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
|
|
}
|
|
|
|
// tests, tests whether the given input would result in a successful
|
|
// call. Checks argument list count and matches input to `input`.
|
|
func (abi ABI) pack(name string, args ...interface{}) ([]byte, error) {
|
|
method := abi.Methods[name]
|
|
|
|
var ret []byte
|
|
for i, a := range args {
|
|
input := method.Inputs[i]
|
|
|
|
packed, err := input.Type.pack(a)
|
|
if err != nil {
|
|
return nil, fmt.Errorf("`%s` %v", name, err)
|
|
}
|
|
ret = append(ret, packed...)
|
|
|
|
}
|
|
|
|
return ret, 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) {
|
|
method, exist := abi.Methods[name]
|
|
if !exist {
|
|
return nil, fmt.Errorf("method '%s' not found", name)
|
|
}
|
|
|
|
// start with argument count match
|
|
if len(args) != len(method.Inputs) {
|
|
return nil, fmt.Errorf("argument count mismatch: %d for %d", len(args), len(method.Inputs))
|
|
}
|
|
|
|
arguments, err := abi.pack(name, args...)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
// Set function id
|
|
packed := abi.Methods[name].Id()
|
|
packed = append(packed, arguments...)
|
|
|
|
return packed, nil
|
|
}
|
|
|
|
// 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) {
|
|
index := i * 32
|
|
|
|
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(common.BytesToBig(output[index : index+32]).Uint64())
|
|
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(common.BytesToBig(output[offset : offset+32]).Uint64())
|
|
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)
|
|
}
|
|
|
|
// get the bytes for this return value
|
|
returnOutput = output[offset+32 : offset+32+size]
|
|
default:
|
|
returnOutput = output[index : index+32]
|
|
}
|
|
|
|
// cast bytes to abi return type
|
|
switch t.Type.T {
|
|
case IntTy:
|
|
return common.BytesToBig(returnOutput), nil
|
|
case UintTy:
|
|
return common.BytesToBig(returnOutput), nil
|
|
case BoolTy:
|
|
return common.BytesToBig(returnOutput).Uint64() > 0, nil
|
|
case AddressTy:
|
|
return common.BytesToAddress(returnOutput), nil
|
|
case HashTy:
|
|
return common.BytesToHash(returnOutput), nil
|
|
case BytesTy, FixedBytesTy:
|
|
return returnOutput, nil
|
|
case StringTy:
|
|
return string(returnOutput), nil
|
|
}
|
|
return nil, fmt.Errorf("abi: unknown type %v", t.Type.T)
|
|
}
|
|
|
|
// Call will unmarshal the output of the call in v. It will return an error if
|
|
// invalid type is given or if the output is too short to conform to the ABI
|
|
// spec.
|
|
//
|
|
// Call supports all of the available types and accepts a struct or an interface
|
|
// slice if the return is a tuple.
|
|
func (abi ABI) Call(executer Executer, v interface{}, name string, args ...interface{}) error {
|
|
callData, err := abi.Pack(name, args...)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
return abi.unmarshal(v, name, executer(callData))
|
|
}
|
|
|
|
// these variable are used to determine certain types during type assertion for
|
|
// assignment.
|
|
var (
|
|
r_interSlice = reflect.TypeOf([]interface{}{})
|
|
r_hash = reflect.TypeOf(common.Hash{})
|
|
r_bytes = reflect.TypeOf([]byte{})
|
|
r_byte = reflect.TypeOf(byte(0))
|
|
)
|
|
|
|
// unmarshal output in v according to the abi specification
|
|
func (abi ABI) unmarshal(v interface{}, name string, output []byte) error {
|
|
var method = abi.Methods[name]
|
|
|
|
if len(output) == 0 {
|
|
return fmt.Errorf("abi: unmarshalling empty output")
|
|
}
|
|
|
|
value := reflect.ValueOf(v).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)
|
|
}
|
|
|
|
// 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)
|
|
}
|
|
|
|
} 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 nil
|
|
}
|
|
|
|
// set attempts to assign src to dst by either setting, copying or otherwise.
|
|
//
|
|
// set is a bit more lenient when it comes to assignment and doesn't force an as
|
|
// strict ruleset as bare `reflect` does.
|
|
func set(dst, src reflect.Value, output Argument) error {
|
|
dstType := dst.Type()
|
|
srcType := src.Type()
|
|
|
|
switch {
|
|
case dstType.AssignableTo(src.Type()):
|
|
dst.Set(src)
|
|
case dstType.Kind() == reflect.Array && srcType.Kind() == reflect.Slice:
|
|
if !dstType.Elem().AssignableTo(r_byte) {
|
|
return fmt.Errorf("abi: cannot unmarshal %v in to array of elem %v", src.Type(), dstType.Elem())
|
|
}
|
|
|
|
if dst.Len() < output.Type.Size {
|
|
return fmt.Errorf("abi: cannot unmarshal src (len=%d) in to dst (len=%d)", output.Type.Size, dst.Len())
|
|
}
|
|
reflect.Copy(dst, src)
|
|
default:
|
|
return fmt.Errorf("abi: cannot unmarshal %v in to %v", src.Type(), dst.Type())
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func (abi *ABI) UnmarshalJSON(data []byte) error {
|
|
var fields []struct {
|
|
Type string
|
|
Name string
|
|
Const bool
|
|
Indexed 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 {
|
|
// empty defaults to function according to the abi spec
|
|
case "function", "":
|
|
abi.Methods[field.Name] = Method{
|
|
Name: field.Name,
|
|
Const: field.Const,
|
|
Inputs: field.Inputs,
|
|
Outputs: field.Outputs,
|
|
}
|
|
case "event":
|
|
abi.Events[field.Name] = Event{
|
|
Name: field.Name,
|
|
Inputs: field.Inputs,
|
|
}
|
|
}
|
|
}
|
|
|
|
return nil
|
|
}
|