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accounts/abi: added output parsing & added call mechanism

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Added calling mechanism and return value parsing
pull/2003/head
Jeffrey Wilcke 9 years ago
parent b0fb48c389
commit a0bf2ea7e7
6 changed files with 243 additions and 88 deletions
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  1. 146
      accounts/abi/abi.go
  2. 47
      accounts/abi/abi_test.go
  3. 48
      accounts/abi/argument.go
  4. 76
      accounts/abi/method.go
  5. 2
      accounts/abi/numbers.go
  6. 12
      accounts/abi/type.go

146
accounts/abi/abi.go
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@ -20,75 +20,17 @@ import (
"encoding/json"
"fmt"
"io"
"strings"
"math"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/logger"
"github.com/ethereum/go-ethereum/logger/glog"
)
// Callable method given a `Name` and whether the method is a constant.
// If the method is `Const` no transaction needs to be created for this
// particular Method call. It can easily be simulated using a local VM.
// For example a `Balance()` method only needs to retrieve something
// from the storage and therefor requires no Tx to be send to the
// network. A method such as `Transact` does require a Tx and thus will
// be flagged `true`.
// Input specifies the required input parameters for this gives method.
type Method struct {
Name string
Const bool
Inputs []Argument
Return Type // not yet implemented
}
// Returns the methods string signature according to the ABI spec.
//
// Example
//
// function foo(uint32 a, int b) = "foo(uint32,int256)"
//
// Please note that "int" is substitute for its canonical representation "int256"
func (m Method) String() (out string) {
out += m.Name
types := make([]string, len(m.Inputs))
i := 0
for _, input := range m.Inputs {
types[i] = input.Type.String()
i++
}
out += "(" + strings.Join(types, ",") + ")"
return
}
func (m Method) Id() []byte {
return crypto.Sha3([]byte(m.String()))[:4]
}
// 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
}
func (a *Argument) UnmarshalJSON(data []byte) error {
var extarg struct {
Name string
Type string
}
err := json.Unmarshal(data, &extarg)
if err != nil {
return fmt.Errorf("argument json err: %v", err)
}
a.Type, err = NewType(extarg.Type)
if err != nil {
return err
}
a.Name = extarg.Name
return nil
}
// 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
@ -97,6 +39,18 @@ type ABI struct {
Methods map[string]Method
}
// 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) {
@ -145,6 +99,55 @@ func (abi ABI) Pack(name string, args ...interface{}) ([]byte, error) {
return packed, nil
}
// toGoType parses the input and casts it to the proper type defined by the ABI
// argument in t.
func toGoType(t Argument, input []byte) interface{} {
switch t.Type.T {
case IntTy:
return common.BytesToBig(input)
case UintTy:
return common.BytesToBig(input)
case BoolTy:
return common.BytesToBig(input).Uint64() > 0
case AddressTy:
return common.BytesToAddress(input)
case HashTy:
return common.BytesToHash(input)
}
return nil
}
// Call executes a call and attemps to parse the return values and returns it as
// an interface. It uses the executer method to perform the actual call since
// the abi knows nothing of the lower level calling mechanism.
//
// Call supports all abi types and includes multiple return values. When only
// one item is returned a single interface{} will be returned, if a contract
// method returns multiple values an []interface{} slice is returned.
func (abi ABI) Call(executer Executer, name string, args ...interface{}) interface{} {
callData, err := abi.Pack(name, args...)
if err != nil {
glog.V(logger.Debug).Infoln("pack error:", err)
return nil
}
output := executer(callData)
method := abi.Methods[name]
ret := make([]interface{}, int(math.Max(float64(len(method.Outputs)), float64(len(output)/32))))
for i := 0; i < len(ret); i += 32 {
index := i / 32
ret[index] = toGoType(method.Outputs[index], output[i:i+32])
}
// return single interface
if len(ret) == 1 {
return ret[0]
}
return ret
}
func (abi *ABI) UnmarshalJSON(data []byte) error {
var methods []Method
if err := json.Unmarshal(data, &methods); err != nil {
@ -158,14 +161,3 @@ func (abi *ABI) UnmarshalJSON(data []byte) error {
return nil
}
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
}

47
accounts/abi/abi_test.go
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@ -92,12 +92,12 @@ func TestReader(t *testing.T) {
exp := ABI{
Methods: map[string]Method{
"balance": Method{
"balance", true, nil, Type{},
"balance", true, nil, nil,
},
"send": Method{
"send", false, []Argument{
Argument{"amount", Uint256},
}, Type{},
}, nil,
},
},
}
@ -238,10 +238,10 @@ func TestTestAddress(t *testing.T) {
func TestMethodSignature(t *testing.T) {
String, _ := NewType("string")
String32, _ := NewType("string32")
m := Method{"foo", false, []Argument{Argument{"bar", String32}, Argument{"baz", String}}, Type{}}
m := Method{"foo", false, []Argument{Argument{"bar", String32}, Argument{"baz", String}}, nil}
exp := "foo(string32,string)"
if m.String() != exp {
t.Error("signature mismatch", exp, "!=", m.String())
if m.Sig() != exp {
t.Error("signature mismatch", exp, "!=", m.Sig())
}
idexp := crypto.Sha3([]byte(exp))[:4]
@ -250,10 +250,10 @@ func TestMethodSignature(t *testing.T) {
}
uintt, _ := NewType("uint")
m = Method{"foo", false, []Argument{Argument{"bar", uintt}}, Type{}}
m = Method{"foo", false, []Argument{Argument{"bar", uintt}}, nil}
exp = "foo(uint256)"
if m.String() != exp {
t.Error("signature mismatch", exp, "!=", m.String())
if m.Sig() != exp {
t.Error("signature mismatch", exp, "!=", m.Sig())
}
}
@ -393,3 +393,34 @@ func TestBytes(t *testing.T) {
t.Error("expected error")
}
}
func TestReturn(t *testing.T) {
const definition = `[
{ "name" : "balance", "const" : true, "inputs" : [], "outputs" : [ { "name": "", "type": "hash" } ] },
{ "name" : "name", "const" : true, "inputs" : [], "outputs" : [ { "name": "", "type": "address" } ] }
]`
abi, err := JSON(strings.NewReader(definition))
if err != nil {
t.Fatal(err)
}
r := abi.Call(func([]byte) []byte {
t := make([]byte, 32)
t[0] = 1
return t
}, "balance")
if _, ok := r.(common.Hash); !ok {
t.Errorf("expected type common.Hash, got %T", r)
}
r = abi.Call(func([]byte) []byte {
t := make([]byte, 32)
t[0] = 1
return t
}, "name")
if _, ok := r.(common.Address); !ok {
t.Errorf("expected type common.Address, got %T", r)
}
}

48
accounts/abi/argument.go
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@ -0,0 +1,48 @@
// 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"
)
// 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
}
func (a *Argument) UnmarshalJSON(data []byte) error {
var extarg struct {
Name string
Type string
}
err := json.Unmarshal(data, &extarg)
if err != nil {
return fmt.Errorf("argument json err: %v", err)
}
a.Type, err = NewType(extarg.Type)
if err != nil {
return err
}
a.Name = extarg.Name
return nil
}

76
accounts/abi/method.go
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@ -0,0 +1,76 @@
// 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 (
"fmt"
"strings"
"github.com/ethereum/go-ethereum/crypto"
)
// Callable method given a `Name` and whether the method is a constant.
// If the method is `Const` no transaction needs to be created for this
// particular Method call. It can easily be simulated using a local VM.
// For example a `Balance()` method only needs to retrieve something
// from the storage and therefor requires no Tx to be send to the
// network. A method such as `Transact` does require a Tx and thus will
// be flagged `true`.
// Input specifies the required input parameters for this gives method.
type Method struct {
Name string
Const bool
Inputs []Argument
Outputs []Argument
}
// Sig returns the methods string signature according to the ABI spec.
//
// Example
//
// function foo(uint32 a, int b) = "foo(uint32,int256)"
//
// Please note that "int" is substitute for its canonical representation "int256"
func (m Method) Sig() string {
types := make([]string, len(m.Inputs))
i := 0
for _, input := range m.Inputs {
types[i] = input.Type.String()
i++
}
return fmt.Sprintf("%v(%v)", m.Name, strings.Join(types, ","))
}
func (m Method) String() string {
inputs := make([]string, len(m.Inputs))
for i, input := range m.Inputs {
inputs[i] = fmt.Sprintf("%v %v", input.Name, input.Type)
}
outputs := make([]string, len(m.Outputs))
for i, output := range m.Outputs {
if len(output.Name) > 0 {
outputs[i] = fmt.Sprintf("%v ", output.Name)
}
outputs[i] += output.Type.String()
}
return fmt.Sprintf("function %v(%v) returns(%v)", m.Name, strings.Join(inputs, ", "), strings.Join(outputs, ", "))
}
func (m Method) Id() []byte {
return crypto.Sha3([]byte(m.Sig()))[:4]
}

2
accounts/abi/numbers.go
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@ -37,6 +37,8 @@ var int8_t = reflect.TypeOf(int8(0))
var int16_t = reflect.TypeOf(int16(0))
var int32_t = reflect.TypeOf(int32(0))
var int64_t = reflect.TypeOf(int64(0))
var hash_t = reflect.TypeOf(common.Hash{})
var address_t = reflect.TypeOf(common.Address{})
var uint_ts = reflect.TypeOf([]uint(nil))
var uint8_ts = reflect.TypeOf([]uint8(nil))

12
accounts/abi/type.go
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@ -31,6 +31,7 @@ const (
BoolTy
SliceTy
AddressTy
HashTy
RealTy
)
@ -121,7 +122,7 @@ func NewType(t string) (typ Type, err error) {
typ.Kind = reflect.Invalid
case "address":
typ.Kind = reflect.Slice
typ.Type = byte_ts
typ.Type = address_t
typ.Size = 20
typ.T = AddressTy
case "string":
@ -130,6 +131,11 @@ func NewType(t string) (typ Type, err error) {
if vsize > 0 {
typ.Size = 32
}
case "hash":
typ.Kind = reflect.Slice
typ.Size = 32
typ.Type = hash_t
typ.T = HashTy
case "bytes":
typ.Kind = reflect.Slice
typ.Type = byte_ts
@ -206,9 +212,9 @@ func (t Type) pack(v interface{}) ([]byte, error) {
}
case reflect.Array:
if v, ok := value.Interface().(common.Address); ok {
return t.pack(v[:])
return common.LeftPadBytes(v[:], 32), nil
} else if v, ok := value.Interface().(common.Hash); ok {
return t.pack(v[:])
return v[:], nil
}
}

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