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rlp: display decoder target type in more error messages
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Decode error messages now say "expected input list for foo.MyStruct"
instead of just "expected List".
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@fjl
fjl committed Dec 9, 2014
1 parent 829730d commit 6cf4e03
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Showing 2 changed files with 33 additions and 27 deletions.
42 changes: 24 additions & 18 deletions rlp/decode.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -82,6 +82,20 @@ func (err decodeError) Error() string {
return fmt.Sprintf("rlp: %s for %v", err.msg, err.typ)
}

func wrapStreamError(err error, typ reflect.Type) error {
switch err {
case ErrExpectedList:
return decodeError{"expected input list", typ}
case ErrExpectedString:
return decodeError{"expected input string or byte", typ}
case errUintOverflow:
return decodeError{"input string too long", typ}
case errNotAtEOL:
return decodeError{"input list has too many elements", typ}
}
return err
}

var (
decoderInterface = reflect.TypeOf(new(Decoder)).Elem()
bigInt = reflect.TypeOf(big.Int{})
Expand Down Expand Up @@ -118,10 +132,8 @@ func makeDecoder(typ reflect.Type) (dec decoder, err error) {
func decodeUint(s *Stream, val reflect.Value) error {
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
if err != nil {
return wrapStreamError(err, val.Type())
}
val.SetUint(num)
return nil
Expand All @@ -130,7 +142,7 @@ func decodeUint(s *Stream, val reflect.Value) error {
func decodeString(s *Stream, val reflect.Value) error {
b, err := s.Bytes()
if err != nil {
return err
return wrapStreamError(err, val.Type())
}
val.SetString(string(b))
return nil
Expand All @@ -143,7 +155,7 @@ func decodeBigIntNoPtr(s *Stream, val reflect.Value) error {
func decodeBigInt(s *Stream, val reflect.Value) error {
b, err := s.Bytes()
if err != nil {
return err
return wrapStreamError(err, val.Type())
}
i := val.Interface().(*big.Int)
if i == nil {
Expand Down Expand Up @@ -181,7 +193,7 @@ func makeListDecoder(typ reflect.Type) (decoder, error) {
func decodeListSlice(s *Stream, val reflect.Value, elemdec decoder) error {
size, err := s.List()
if err != nil {
return err
return wrapStreamError(err, val.Type())
}
if size == 0 {
val.Set(reflect.MakeSlice(val.Type(), 0, 0))
Expand Down Expand Up @@ -242,10 +254,7 @@ func decodeListArray(s *Stream, val reflect.Value, elemdec decoder) error {
if i < vlen {
zero(val, i)
}
if err = s.ListEnd(); err == errNotAtEOL {
return decodeError{"input list has too many elements", val.Type()}
}
return err
return wrapStreamError(s.ListEnd(), val.Type())
}

func decodeByteSlice(s *Stream, val reflect.Value) error {
Expand All @@ -271,14 +280,14 @@ func decodeByteArray(s *Stream, val reflect.Value) error {
switch kind {
case Byte:
if val.Len() == 0 {
return decodeError{"input string too big", val.Type()}
return decodeError{"input string too long", val.Type()}
}
bv, _ := s.Uint()
val.Index(0).SetUint(bv)
zero(val, 1)
case String:
if uint64(val.Len()) < size {
return decodeError{"input string too big", val.Type()}
return decodeError{"input string too long", val.Type()}
}
slice := val.Slice(0, int(size)).Interface().([]byte)
if err := s.readFull(slice); err != nil {
Expand Down Expand Up @@ -317,7 +326,7 @@ func makeStructDecoder(typ reflect.Type) (decoder, error) {
}
dec := func(s *Stream, val reflect.Value) (err error) {
if _, err = s.List(); err != nil {
return err
return wrapStreamError(err, typ)
}
for _, f := range fields {
err = f.info.decoder(s, val.Field(f.index))
Expand All @@ -328,10 +337,7 @@ func makeStructDecoder(typ reflect.Type) (decoder, error) {
return err
}
}
if err = s.ListEnd(); err == errNotAtEOL {
err = decodeError{"input list has too many elements", typ}
}
return err
return wrapStreamError(s.ListEnd(), typ)
}
return dec, nil
}
Expand Down
18 changes: 9 additions & 9 deletions rlp/decode_test.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -213,8 +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: "rlp: input string too big for uint32"},
{input: "C0", ptr: new(uint32), error: ErrExpectedString.Error()},
{input: "850505050505", ptr: new(uint32), error: "rlp: input string too long for uint32"},
{input: "C0", ptr: new(uint32), error: "rlp: expected input string or byte for uint32"},

// slices
{input: "C0", ptr: new([]uint), value: []uint{}},
Expand All @@ -231,16 +231,16 @@ var decodeTests = []decodeTest{
{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: "rlp: input string too big for uint8"},
{input: "C3820102", ptr: new([]byte), error: "rlp: input string too long 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: "rlp: input string too big for uint8"},
{input: "86010203040506", ptr: new([5]byte), error: "rlp: input string too big for [5]uint8"},
{input: "C3820102", ptr: new([5]byte), error: "rlp: input string too long for uint8"},
{input: "86010203040506", ptr: new([5]byte), error: "rlp: input string too long for [5]uint8"},
{input: "850101", ptr: new([5]byte), error: io.ErrUnexpectedEOF.Error()},

// byte array reuse (should be zeroed)
Expand All @@ -254,19 +254,19 @@ 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: "rlp: input string too big for [0]uint8"},
{input: "8101", ptr: new([0]byte), error: "rlp: input string too big for [0]uint8"},
{input: "01", ptr: new([0]byte), error: "rlp: input string too long for [0]uint8"},
{input: "8101", ptr: new([0]byte), error: "rlp: input string too long 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.Error()},
{input: "C0", ptr: new(string), error: "rlp: expected input string or byte for string"},

// 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.Error()},
{input: "C0", ptr: new(*big.Int), error: "rlp: expected input string or byte for *big.Int"},

// structs
{input: "C0", ptr: new(simplestruct), value: simplestruct{0, ""}},
Expand Down

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