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rlp: include target type in decoder error messages
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@fjl
fjl committed Nov 25, 2014
1 parent 6049fcd commit f816fdc
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Showing 2 changed files with 42 additions and 28 deletions.
37 changes: 26 additions & 11 deletions rlp/decode.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -72,6 +72,15 @@ func Decode(r io.Reader, val interface{}) error {
return NewStream(r).Decode(val)
}

type decodeError struct {
msg string
typ reflect.Type
}

func (err decodeError) Error() string {
return fmt.Sprintf("rlp: %s for %v", err.msg, err.typ)
}

func makeNumDecoder(typ reflect.Type) decoder {
kind := typ.Kind()
switch {
Expand All @@ -85,17 +94,23 @@ func makeNumDecoder(typ reflect.Type) decoder {
}

func decodeInt(s *Stream, val reflect.Value) error {
num, err := s.uint(val.Type().Bits())
if err != nil {
typ := val.Type()
num, err := s.uint(typ.Bits())
if err == errUintOverflow {
return decodeError{"input string too long", typ}
} else if err != nil {
return err
}
val.SetInt(int64(num))
return nil
}

func decodeUint(s *Stream, val reflect.Value) error {
num, err := s.uint(val.Type().Bits())
if err != nil {
typ := val.Type()
num, err := s.uint(typ.Bits())
if err == errUintOverflow {
return decodeError{"input string too big", typ}
} else if err != nil {
return err
}
val.SetUint(num)
Expand Down Expand Up @@ -177,7 +192,7 @@ func decodeList(s *Stream, val reflect.Value, elemdec decoder, maxelem int) erro
i := 0
for {
if i > maxelem {
return fmt.Errorf("rlp: input List has more than %d elements", maxelem)
return decodeError{"input list has too many elements", val.Type()}
}
if val.Kind() == reflect.Slice {
// grow slice if necessary
Expand Down Expand Up @@ -228,8 +243,6 @@ func decodeByteSlice(s *Stream, val reflect.Value) error {
return err
}

var errStringDoesntFitArray = errors.New("rlp: string value doesn't fit into target array")

func decodeByteArray(s *Stream, val reflect.Value) error {
kind, size, err := s.Kind()
if err != nil {
Expand All @@ -238,14 +251,14 @@ func decodeByteArray(s *Stream, val reflect.Value) error {
switch kind {
case Byte:
if val.Len() == 0 {
return errStringDoesntFitArray
return decodeError{"input string too big", val.Type()}
}
bv, _ := s.Uint()
val.Index(0).SetUint(bv)
zero(val, 1)
case String:
if uint64(val.Len()) < size {
return errStringDoesntFitArray
return decodeError{"input string too big", val.Type()}
}
slice := val.Slice(0, int(size)).Interface().([]byte)
if err := s.readFull(slice); err != nil {
Expand Down Expand Up @@ -295,7 +308,7 @@ func makeStructDecoder(typ reflect.Type) (decoder, error) {
}
}
if err = s.ListEnd(); err == errNotAtEOL {
err = errors.New("rlp: input List has too many elements")
err = decodeError{"input list has too many elements", typ}
}
return err
}
Expand Down Expand Up @@ -476,6 +489,8 @@ func (s *Stream) Bytes() ([]byte, error) {
}
}

var errUintOverflow = errors.New("rlp: uint overflow")

// Uint reads an RLP string of up to 8 bytes and returns its contents
// as an unsigned integer. If the input does not contain an RLP string, the
// returned error will be ErrExpectedString.
Expand All @@ -494,7 +509,7 @@ func (s *Stream) uint(maxbits int) (uint64, error) {
return uint64(s.byteval), nil
case String:
if size > uint64(maxbits/8) {
return 0, fmt.Errorf("rlp: string is larger than %d bits", maxbits)
return 0, errUintOverflow
}
return s.readUint(byte(size))
default:
Expand Down
33 changes: 16 additions & 17 deletions rlp/decode_test.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,6 @@ package rlp
import (
"bytes"
"encoding/hex"
"errors"
"fmt"
"io"
"math/big"
Expand Down Expand Up @@ -87,7 +86,7 @@ func TestStreamErrors(t *testing.T) {
{"81", calls{"Bytes"}, io.ErrUnexpectedEOF},
{"81", calls{"Uint"}, io.ErrUnexpectedEOF},
{"BFFFFFFFFFFFFFFF", calls{"Bytes"}, io.ErrUnexpectedEOF},
{"89000000000000000001", calls{"Uint"}, errors.New("rlp: string is larger than 64 bits")},
{"89000000000000000001", calls{"Uint"}, errUintOverflow},
{"00", calls{"List"}, ErrExpectedList},
{"80", calls{"List"}, ErrExpectedList},
{"C0", calls{"List", "Uint"}, EOL},
Expand Down Expand Up @@ -181,7 +180,7 @@ type decodeTest struct {
input string
ptr interface{}
value interface{}
error error
error string
}

type simplestruct struct {
Expand Down Expand Up @@ -214,8 +213,8 @@ var decodeTests = []decodeTest{
{input: "820505", ptr: new(uint32), value: uint32(0x0505)},
{input: "83050505", ptr: new(uint32), value: uint32(0x050505)},
{input: "8405050505", ptr: new(uint32), value: uint32(0x05050505)},
{input: "850505050505", ptr: new(uint32), error: errors.New("rlp: string is larger than 32 bits")},
{input: "C0", ptr: new(uint32), error: ErrExpectedString},
{input: "850505050505", ptr: new(uint32), error: "rlp: input string too big for uint32"},
{input: "C0", ptr: new(uint32), error: ErrExpectedString.Error()},

// slices
{input: "C0", ptr: new([]int), value: []int{}},
Expand All @@ -224,25 +223,25 @@ var decodeTests = []decodeTest{
// arrays
{input: "C0", ptr: new([5]int), value: [5]int{}},
{input: "C50102030405", ptr: new([5]int), value: [5]int{1, 2, 3, 4, 5}},
{input: "C6010203040506", ptr: new([5]int), error: errors.New("rlp: input List has more than 5 elements")},
{input: "C6010203040506", ptr: new([5]int), error: "rlp: input list has too many elements for [5]int"},

// byte slices
{input: "01", ptr: new([]byte), value: []byte{1}},
{input: "80", ptr: new([]byte), value: []byte{}},
{input: "8D6162636465666768696A6B6C6D", ptr: new([]byte), value: []byte("abcdefghijklm")},
{input: "C0", ptr: new([]byte), value: []byte{}},
{input: "C3010203", ptr: new([]byte), value: []byte{1, 2, 3}},
{input: "C3820102", ptr: new([]byte), error: errors.New("rlp: string is larger than 8 bits")},
{input: "C3820102", ptr: new([]byte), error: "rlp: input string too big for uint8"},

// byte arrays
{input: "01", ptr: new([5]byte), value: [5]byte{1}},
{input: "80", ptr: new([5]byte), value: [5]byte{}},
{input: "850102030405", ptr: new([5]byte), value: [5]byte{1, 2, 3, 4, 5}},
{input: "C0", ptr: new([5]byte), value: [5]byte{}},
{input: "C3010203", ptr: new([5]byte), value: [5]byte{1, 2, 3, 0, 0}},
{input: "C3820102", ptr: new([5]byte), error: errors.New("rlp: string is larger than 8 bits")},
{input: "86010203040506", ptr: new([5]byte), error: errStringDoesntFitArray},
{input: "850101", ptr: new([5]byte), error: io.ErrUnexpectedEOF},
{input: "C3820102", ptr: new([5]byte), error: "rlp: input string too big for uint8"},
{input: "86010203040506", ptr: new([5]byte), error: "rlp: input string too big for [5]uint8"},
{input: "850101", ptr: new([5]byte), error: io.ErrUnexpectedEOF.Error()},

// byte array reuse (should be zeroed)
{input: "850102030405", ptr: &sharedByteArray, value: [5]byte{1, 2, 3, 4, 5}},
Expand All @@ -255,25 +254,25 @@ var decodeTests = []decodeTest{
// zero sized byte arrays
{input: "80", ptr: new([0]byte), value: [0]byte{}},
{input: "C0", ptr: new([0]byte), value: [0]byte{}},
{input: "01", ptr: new([0]byte), error: errStringDoesntFitArray},
{input: "8101", ptr: new([0]byte), error: errStringDoesntFitArray},
{input: "01", ptr: new([0]byte), error: "rlp: input string too big for [0]uint8"},
{input: "8101", ptr: new([0]byte), error: "rlp: input string too big for [0]uint8"},

// strings
{input: "00", ptr: new(string), value: "\000"},
{input: "8D6162636465666768696A6B6C6D", ptr: new(string), value: "abcdefghijklm"},
{input: "C0", ptr: new(string), error: ErrExpectedString},
{input: "C0", ptr: new(string), error: ErrExpectedString.Error()},

// big ints
{input: "01", ptr: new(*big.Int), value: big.NewInt(1)},
{input: "89FFFFFFFFFFFFFFFFFF", ptr: new(*big.Int), value: veryBigInt},
{input: "10", ptr: new(big.Int), value: *big.NewInt(16)}, // non-pointer also works
{input: "C0", ptr: new(*big.Int), error: ErrExpectedString},
{input: "C0", ptr: new(*big.Int), error: ErrExpectedString.Error()},

// structs
{input: "C0", ptr: new(simplestruct), value: simplestruct{0, ""}},
{input: "C105", ptr: new(simplestruct), value: simplestruct{5, ""}},
{input: "C50583343434", ptr: new(simplestruct), value: simplestruct{5, "444"}},
{input: "C3010101", ptr: new(simplestruct), error: errors.New("rlp: input List has too many elements")},
{input: "C3010101", ptr: new(simplestruct), error: "rlp: input list has too many elements for rlp.simplestruct"},
{
input: "C501C302C103",
ptr: new(recstruct),
Expand Down Expand Up @@ -312,12 +311,12 @@ func runTests(t *testing.T, decode func([]byte, interface{}) error) {
continue
}
err = decode(input, test.ptr)
if err != nil && test.error == nil {
if err != nil && test.error == "" {
t.Errorf("test %d: unexpected Decode error: %v\ndecoding into %T\ninput %q",
i, err, test.ptr, test.input)
continue
}
if test.error != nil && fmt.Sprint(err) != fmt.Sprint(test.error) {
if test.error != "" && fmt.Sprint(err) != test.error {
t.Errorf("test %d: Decode error mismatch\ngot %v\nwant %v\ndecoding into %T\ninput %q",
i, err, test.error, test.ptr, test.input)
continue
Expand Down

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