// 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 tests
import (
"bytes"
"encoding/hex"
"errors"
"fmt"
"math/big"
"strings"
"github.com/dexon-foundation/dexon/rlp"
)
// RLPTest is the JSON structure of a single RLP test.
type RLPTest struct {
// If the value of In is "INVALID" or "VALID", the test
// checks whether Out can be decoded into a value of
// type interface{}.
//
// For other JSON values, In is treated as a driver for
// calls to rlp.Stream. The test also verifies that encoding
// In produces the bytes in Out.
In interface{}
// Out is a hex-encoded RLP value.
Out string
}
// FromHex returns the bytes represented by the hexadecimal string s.
// s may be prefixed with "0x".
// This is copy-pasted from bytes.go, which does not return the error
func FromHex(s string) ([]byte, error) {
if len(s) > 1 && (s[0:2] == "0x" || s[0:2] == "0X") {
s = s[2:]
}
if len(s)%2 == 1 {
s = "0" + s
}
return hex.DecodeString(s)
}
// Run executes the test.
func (t *RLPTest) Run() error {
outb, err := FromHex(t.Out)
if err != nil {
return fmt.Errorf("invalid hex in Out")
}
// Handle simple decoding tests with no actual In value.
if t.In == "VALID" || t.In == "INVALID" {
return checkDecodeInterface(outb, t.In == "VALID")
}
// Check whether encoding the value produces the same bytes.
in := translateJSON(t.In)
b, err := rlp.EncodeToBytes(in)
if err != nil {
return fmt.Errorf("encode failed: %v", err)
}
if !bytes.Equal(b, outb) {
return fmt.Errorf("encode produced %x, want %x", b, outb)
}
// Test stream decoding.
s := rlp.NewStream(bytes.NewReader(outb), 0)
return checkDecodeFromJSON(s, in)
}
func checkDecodeInterface(b []byte, isValid bool) error {
err := rlp.DecodeBytes(b, new(interface{}))
switch {
case isValid && err != nil:
return fmt.Errorf("decoding failed: %v", err)
case !isValid && err == nil:
return fmt.Errorf("decoding of invalid value succeeded")
}
return nil
}
// translateJSON makes test json values encodable with RLP.
func translateJSON(v interface{}) interface{} {
switch v := v.(type) {
case float64:
return uint64(v)
case string:
if len(v) > 0 && v[0] == '#' { // # starts a faux big int.
big, ok := new(big.Int).SetString(v[1:], 10)
if !ok {
panic(fmt.Errorf("bad test: bad big int: %q", v))
}
return big
}
return []byte(v)
case []interface{}:
new := make([]interface{}, len(v))
for i := range v {
new[i] = translateJSON(v[i])
}
return new
default:
panic(fmt.Errorf("can't handle %T", v))
}
}
// checkDecodeFromJSON decodes from s guided by exp. exp drives the
// Stream by invoking decoding operations (Uint, Big, List, ...) based
// on the type of each value. The value decoded from the RLP stream
// must match the JSON value.
func checkDecodeFromJSON(s *rlp.Stream, exp interface{}) error {
switch exp := exp.(type) {
case uint64:
i, err := s.Uint()
if err != nil {
return addStack("Uint", exp, err)
}
if i != exp {
return addStack("Uint", exp, fmt.Errorf("result mismatch: got %d", i))
}
case *big.Int:
big := new(big.Int)
if err := s.Decode(&big); err != nil {
return addStack("Big", exp, err)
}
if big.Cmp(exp) != 0 {
return addStack("Big", exp, fmt.Errorf("result mismatch: got %d", big))
}
case []byte:
b, err := s.Bytes()
if err != nil {
return addStack("Bytes", exp, err)
}
if !bytes.Equal(b, exp) {
return addStack("Bytes", exp, fmt.Errorf("result mismatch: got %x", b))
}
case []interface{}:
if _, err := s.List(); err != nil {
return addStack("List", exp, err)
}
for i, v := range exp {
if err := checkDecodeFromJSON(s, v); err != nil {
return addStack(fmt.Sprintf("[%d]", i), exp, err)
}
}
if err := s.ListEnd(); err != nil {
return addStack("ListEnd", exp, err)
}
default:
panic(fmt.Errorf("unhandled type: %T", exp))
}
return nil
}
func addStack(op string, val interface{}, err error) error {
lines := strings.Split(err.Error(), "\n")
lines = append(lines, fmt.Sprintf("\t%s: %v", op, val))
return errors.New(strings.Join(lines, "\n"))
}
