From 74266d5bbd95ac07882b09230aec876bf7704f69 Mon Sep 17 00:00:00 2001
From: Felix Lange <fjl@twurst.com>
Date: Thu, 13 Nov 2014 20:31:48 +0100
Subject: [PATCH] rlp: new package for streaming RLP decoder
---
rlp/decode.go | 666 +++++++++++++++++++++++++++++++++++++++++++++
rlp/decode_test.go | 469 +++++++++++++++++++++++++++++++
rlp/doc.go | 17 ++
rlp/typecache.go | 91 +++++++
4 files changed, 1243 insertions(+)
create mode 100644 rlp/decode.go
create mode 100644 rlp/decode_test.go
create mode 100644 rlp/doc.go
create mode 100644 rlp/typecache.go
diff --git a/rlp/decode.go b/rlp/decode.go
new file mode 100644
index 000000000..1a51e7130
--- /dev/null
+++ b/rlp/decode.go
@@ -0,0 +1,666 @@
+package rlp
+
+import (
+ "encoding/binary"
+ "errors"
+ "fmt"
+ "io"
+ "math/big"
+ "reflect"
+)
+
+var (
+ errNoPointer = errors.New("rlp: interface given to Decode must be a pointer")
+ errDecodeIntoNil = errors.New("rlp: pointer given to Decode must not be nil")
+)
+
+// Decoder is implemented by types that require custom RLP
+// decoding rules or need to decode into private fields.
+//
+// The DecodeRLP method should read one value from the given
+// Stream. It is not forbidden to read less or more, but it might
+// be confusing.
+type Decoder interface {
+ DecodeRLP(*Stream) error
+}
+
+// Decode parses RLP-encoded data from r and stores the result
+// in the value pointed to by val. Val must be a non-nil pointer.
+//
+// Decode uses the following type-dependent decoding rules:
+//
+// If the type implements the Decoder interface, decode calls
+// DecodeRLP.
+//
+// To decode into a pointer, Decode will set the pointer to nil if the
+// input has size zero or the input is a single byte with value zero.
+// If the input has nonzero size, Decode will allocate a new value of
+// the type being pointed to.
+//
+// To decode into a struct, Decode expects the input to be an RLP
+// list. The decoded elements of the list are assigned to each public
+// field in the order given by the struct's definition. If the input
+// list has too few elements, no error is returned and the remaining
+// fields will have the zero value.
+// Recursive struct types are supported.
+//
+// To decode into a slice, the input must be a list and the resulting
+// slice will contain the input elements in order.
+// As a special case, if the slice has a byte-size element type, the input
+// can also be an RLP string.
+//
+// To decode into a Go string, the input must be an RLP string. The
+// bytes are taken as-is and will not necessarily be valid UTF-8.
+//
+// To decode into an integer type, the input must also be an RLP
+// string. The bytes are interpreted as a big endian representation of
+// the integer. If the RLP string is larger than the bit size of the
+// type, Decode will return an error. Decode also supports *big.Int.
+// There is no size limit for big integers.
+//
+// To decode into an interface value, Decode stores one of these
+// in the value:
+//
+// []interface{}, for RLP lists
+// []byte, for RLP strings
+//
+// Non-empty interface types are not supported, nor are bool, float32,
+// float64, maps, channel types and functions.
+func Decode(r ByteReader, val interface{}) error {
+ return NewStream(r).Decode(val)
+}
+
+func makeNumDecoder(typ reflect.Type) decoder {
+ kind := typ.Kind()
+ switch {
+ case kind <= reflect.Int64:
+ return decodeInt
+ case kind <= reflect.Uint64:
+ return decodeUint
+ default:
+ panic("fallthrough")
+ }
+}
+
+func decodeInt(s *Stream, val reflect.Value) error {
+ num, err := s.uint(val.Type().Bits())
+ 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 {
+ return err
+ }
+ val.SetUint(num)
+ return nil
+}
+
+func decodeString(s *Stream, val reflect.Value) error {
+ b, err := s.Bytes()
+ if err != nil {
+ return err
+ }
+ val.SetString(string(b))
+ return nil
+}
+
+func decodeBigIntNoPtr(s *Stream, val reflect.Value) error {
+ return decodeBigInt(s, val.Addr())
+}
+
+func decodeBigInt(s *Stream, val reflect.Value) error {
+ b, err := s.Bytes()
+ if err != nil {
+ return err
+ }
+ i := val.Interface().(*big.Int)
+ if i == nil {
+ i = new(big.Int)
+ val.Set(reflect.ValueOf(i))
+ }
+ i.SetBytes(b)
+ return nil
+}
+
+const maxInt = int(^uint(0) >> 1)
+
+func makeListDecoder(typ reflect.Type) (decoder, error) {
+ etype := typ.Elem()
+ if etype.Kind() == reflect.Uint8 && !reflect.PtrTo(etype).Implements(decoderInterface) {
+ if typ.Kind() == reflect.Array {
+ return decodeByteArray, nil
+ } else {
+ return decodeByteSlice, nil
+ }
+ }
+ etypeinfo, err := cachedTypeInfo1(etype)
+ if err != nil {
+ return nil, err
+ }
+ var maxLen = maxInt
+ if typ.Kind() == reflect.Array {
+ maxLen = typ.Len()
+ }
+ dec := func(s *Stream, val reflect.Value) error {
+ return decodeList(s, val, etypeinfo.decoder, maxLen)
+ }
+ return dec, nil
+}
+
+// decodeList decodes RLP list elements into slices and arrays.
+//
+// The approach here is stolen from package json, although we differ
+// in the semantics for arrays. package json discards remaining
+// elements that would not fit into the array. We generate an error in
+// this case because we'd be losing information.
+func decodeList(s *Stream, val reflect.Value, elemdec decoder, maxelem int) error {
+ size, err := s.List()
+ if err != nil {
+ return err
+ }
+ if size == 0 {
+ if val.Kind() == reflect.Slice {
+ val.Set(reflect.MakeSlice(val.Type(), 0, 0))
+ } else {
+ zero(val, 0)
+ }
+ return s.ListEnd()
+ }
+
+ i := 0
+ for {
+ if i > maxelem {
+ return fmt.Errorf("rlp: input List has more than %d elements", maxelem)
+ }
+ if val.Kind() == reflect.Slice {
+ // grow slice if necessary
+ if i >= val.Cap() {
+ newcap := val.Cap() + val.Cap()/2
+ if newcap < 4 {
+ newcap = 4
+ }
+ newv := reflect.MakeSlice(val.Type(), val.Len(), newcap)
+ reflect.Copy(newv, val)
+ val.Set(newv)
+ }
+ if i >= val.Len() {
+ val.SetLen(i + 1)
+ }
+ }
+ // decode into element
+ if err := elemdec(s, val.Index(i)); err == EOL {
+ break
+ } else if err != nil {
+ return err
+ }
+ i++
+ }
+ if i < val.Len() {
+ if val.Kind() == reflect.Array {
+ // zero the rest of the array.
+ zero(val, i)
+ } else {
+ val.SetLen(i)
+ }
+ }
+ return s.ListEnd()
+}
+
+func decodeByteSlice(s *Stream, val reflect.Value) error {
+ kind, _, err := s.Kind()
+ if err != nil {
+ return err
+ }
+ if kind == List {
+ return decodeList(s, val, decodeUint, maxInt)
+ }
+ b, err := s.Bytes()
+ if err == nil {
+ val.SetBytes(b)
+ }
+ 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 {
+ return err
+ }
+ switch kind {
+ case Byte:
+ if val.Len() == 0 {
+ return errStringDoesntFitArray
+ }
+ bv, _ := s.Uint()
+ val.Index(0).SetUint(bv)
+ zero(val, 1)
+ case String:
+ if uint64(val.Len()) < size {
+ return errStringDoesntFitArray
+ }
+ slice := val.Slice(0, int(size)).Interface().([]byte)
+ if err := s.readFull(slice); err != nil {
+ return err
+ }
+ zero(val, int(size))
+ case List:
+ return decodeList(s, val, decodeUint, val.Len())
+ }
+ return nil
+}
+
+func zero(val reflect.Value, start int) {
+ z := reflect.Zero(val.Type().Elem())
+ for i := start; i < val.Len(); i++ {
+ val.Index(i).Set(z)
+ }
+}
+
+type field struct {
+ index int
+ info *typeinfo
+}
+
+func makeStructDecoder(typ reflect.Type) (decoder, error) {
+ var fields []field
+ for i := 0; i < typ.NumField(); i++ {
+ if f := typ.Field(i); f.PkgPath == "" { // exported
+ info, err := cachedTypeInfo1(f.Type)
+ if err != nil {
+ return nil, err
+ }
+ fields = append(fields, field{i, info})
+ }
+ }
+ dec := func(s *Stream, val reflect.Value) (err error) {
+ if _, err = s.List(); err != nil {
+ return err
+ }
+ for _, f := range fields {
+ err = f.info.decoder(s, val.Field(f.index))
+ if err == EOL {
+ // too few elements. leave the rest at their zero value.
+ break
+ } else if err != nil {
+ return err
+ }
+ }
+ if err = s.ListEnd(); err == errNotAtEOL {
+ err = errors.New("rlp: input List has too many elements")
+ }
+ return err
+ }
+ return dec, nil
+}
+
+func makePtrDecoder(typ reflect.Type) (decoder, error) {
+ etype := typ.Elem()
+ etypeinfo, err := cachedTypeInfo1(etype)
+ if err != nil {
+ return nil, err
+ }
+ dec := func(s *Stream, val reflect.Value) (err error) {
+ _, size, err := s.Kind()
+ if err != nil || size == 0 && s.byteval == 0 {
+ return err
+ }
+ newval := val
+ if val.IsNil() {
+ newval = reflect.New(etype)
+ }
+ if err = etypeinfo.decoder(s, newval.Elem()); err == nil {
+ val.Set(newval)
+ }
+ return err
+ }
+ return dec, nil
+}
+
+var ifsliceType = reflect.TypeOf([]interface{}{})
+
+func decodeInterface(s *Stream, val reflect.Value) error {
+ kind, _, err := s.Kind()
+ if err != nil {
+ return err
+ }
+ if kind == List {
+ slice := reflect.New(ifsliceType).Elem()
+ if err := decodeList(s, slice, decodeInterface, maxInt); err != nil {
+ return err
+ }
+ val.Set(slice)
+ } else {
+ b, err := s.Bytes()
+ if err != nil {
+ return err
+ }
+ val.Set(reflect.ValueOf(b))
+ }
+ return nil
+}
+
+// This decoder is used for non-pointer values of types
+// that implement the Decoder interface using a pointer receiver.
+func decodeDecoderNoPtr(s *Stream, val reflect.Value) error {
+ return val.Addr().Interface().(Decoder).DecodeRLP(s)
+}
+
+func decodeDecoder(s *Stream, val reflect.Value) error {
+ // Decoder instances are not handled using the pointer rule if the type
+ // implements Decoder with pointer receiver (i.e. always)
+ // because it might handle empty values specially.
+ // We need to allocate one here in this case, like makePtrDecoder does.
+ if val.Kind() == reflect.Ptr && val.IsNil() {
+ val.Set(reflect.New(val.Type().Elem()))
+ }
+ return val.Interface().(Decoder).DecodeRLP(s)
+}
+
+// Kind represents the kind of value contained in an RLP stream.
+type Kind int
+
+const (
+ Byte Kind = iota
+ String
+ List
+)
+
+func (k Kind) String() string {
+ switch k {
+ case Byte:
+ return "Byte"
+ case String:
+ return "String"
+ case List:
+ return "List"
+ default:
+ return fmt.Sprintf("Unknown(%d)", k)
+ }
+}
+
+var (
+ // EOL is returned when the end of the current list
+ // has been reached during streaming.
+ EOL = errors.New("rlp: end of list")
+
+ // Other errors
+ ErrExpectedString = errors.New("rlp: expected String or Byte")
+ ErrExpectedList = errors.New("rlp: expected List")
+ ErrElemTooLarge = errors.New("rlp: element is larger than containing list")
+
+ // internal errors
+ errNotInList = errors.New("rlp: call of ListEnd outside of any list")
+ errNotAtEOL = errors.New("rlp: call of ListEnd not positioned at EOL")
+)
+
+// ByteReader must be implemented by any input reader for a Stream. It
+// is implemented by e.g. bufio.Reader and bytes.Reader.
+type ByteReader interface {
+ io.Reader
+ io.ByteReader
+}
+
+// Stream can be used for piecemeal decoding of an input stream. This
+// is useful if the input is very large or if the decoding rules for a
+// type depend on the input structure. Stream does not keep an
+// internal buffer. After decoding a value, the input reader will be
+// positioned just before the type information for the next value.
+//
+// When decoding a list and the input position reaches the declared
+// length of the list, all operations will return error EOL.
+// The end of the list must be acknowledged using ListEnd to continue
+// reading the enclosing list.
+//
+// Stream is not safe for concurrent use.
+type Stream struct {
+ r ByteReader
+ uintbuf []byte
+
+ kind Kind // kind of value ahead
+ size uint64 // size of value ahead
+ byteval byte // value of single byte in type tag
+ stack []listpos
+}
+
+type listpos struct{ pos, size uint64 }
+
+func NewStream(r ByteReader) *Stream {
+ return &Stream{r: r, uintbuf: make([]byte, 8), kind: -1}
+}
+
+// Bytes reads an RLP string and returns its contents as a byte slice.
+// If the input does not contain an RLP string, the returned
+// error will be ErrExpectedString.
+func (s *Stream) Bytes() ([]byte, error) {
+ kind, size, err := s.Kind()
+ if err != nil {
+ return nil, err
+ }
+ switch kind {
+ case Byte:
+ s.kind = -1 // rearm Kind
+ return []byte{s.byteval}, nil
+ case String:
+ b := make([]byte, size)
+ if err = s.readFull(b); err != nil {
+ return nil, err
+ }
+ return b, nil
+ default:
+ return nil, ErrExpectedString
+ }
+}
+
+// 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.
+func (s *Stream) Uint() (uint64, error) {
+ return s.uint(64)
+}
+
+func (s *Stream) uint(maxbits int) (uint64, error) {
+ kind, size, err := s.Kind()
+ if err != nil {
+ return 0, err
+ }
+ switch kind {
+ case Byte:
+ s.kind = -1 // rearm Kind
+ 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 s.readUint(byte(size))
+ default:
+ return 0, ErrExpectedString
+ }
+}
+
+// List starts decoding an RLP list. If the input does not contain a
+// list, the returned error will be ErrExpectedList. When the list's
+// end has been reached, any Stream operation will return EOL.
+func (s *Stream) List() (size uint64, err error) {
+ kind, size, err := s.Kind()
+ if err != nil {
+ return 0, err
+ }
+ if kind != List {
+ return 0, ErrExpectedList
+ }
+ s.stack = append(s.stack, listpos{0, size})
+ s.kind = -1
+ s.size = 0
+ return size, nil
+}
+
+// ListEnd returns to the enclosing list.
+// The input reader must be positioned at the end of a list.
+func (s *Stream) ListEnd() error {
+ if len(s.stack) == 0 {
+ return errNotInList
+ }
+ tos := s.stack[len(s.stack)-1]
+ if tos.pos != tos.size {
+ return errNotAtEOL
+ }
+ s.stack = s.stack[:len(s.stack)-1] // pop
+ if len(s.stack) > 0 {
+ s.stack[len(s.stack)-1].pos += tos.size
+ }
+ s.kind = -1
+ s.size = 0
+ return nil
+}
+
+// Decode decodes a value and stores the result in the value pointed
+// to by val. Please see the documentation for the Decode function
+// to learn about the decoding rules.
+func (s *Stream) Decode(val interface{}) error {
+ if val == nil {
+ return errDecodeIntoNil
+ }
+ rval := reflect.ValueOf(val)
+ rtyp := rval.Type()
+ if rtyp.Kind() != reflect.Ptr {
+ return errNoPointer
+ }
+ if rval.IsNil() {
+ return errDecodeIntoNil
+ }
+ info, err := cachedTypeInfo(rtyp.Elem())
+ if err != nil {
+ return err
+ }
+ return info.decoder(s, rval.Elem())
+}
+
+// Kind returns the kind and size of the next value in the
+// input stream.
+//
+// The returned size is the number of bytes that make up the value.
+// For kind == Byte, the size is zero because the value is
+// contained in the type tag.
+//
+// The first call to Kind will read size information from the input
+// reader and leave it positioned at the start of the actual bytes of
+// the value. Subsequent calls to Kind (until the value is decoded)
+// will not advance the input reader and return cached information.
+func (s *Stream) Kind() (kind Kind, size uint64, err error) {
+ var tos *listpos
+ if len(s.stack) > 0 {
+ tos = &s.stack[len(s.stack)-1]
+ }
+ if s.kind < 0 {
+ if tos != nil && tos.pos == tos.size {
+ return 0, 0, EOL
+ }
+ kind, size, err = s.readKind()
+ if err != nil {
+ return 0, 0, err
+ }
+ s.kind, s.size = kind, size
+ }
+ if tos != nil && tos.pos+s.size > tos.size {
+ return 0, 0, ErrElemTooLarge
+ }
+ return s.kind, s.size, nil
+}
+
+func (s *Stream) readKind() (kind Kind, size uint64, err error) {
+ b, err := s.readByte()
+ if err != nil {
+ return 0, 0, err
+ }
+ s.byteval = 0
+ switch {
+ case b < 0x80:
+ // For a single byte whose value is in the [0x00, 0x7F] range, that byte
+ // is its own RLP encoding.
+ s.byteval = b
+ return Byte, 0, nil
+ case b < 0xB8:
+ // Otherwise, if a string is 0-55 bytes long,
+ // the RLP encoding consists of a single byte with value 0x80 plus the
+ // length of the string followed by the string. The range of the first
+ // byte is thus [0x80, 0xB7].
+ return String, uint64(b - 0x80), nil
+ case b < 0xC0:
+ // If a string is more than 55 bytes long, the
+ // RLP encoding consists of a single byte with value 0xB7 plus the length
+ // of the length of the string in binary form, followed by the length of
+ // the string, followed by the string. For example, a length-1024 string
+ // would be encoded as 0xB90400 followed by the string. The range of
+ // the first byte is thus [0xB8, 0xBF].
+ size, err = s.readUint(b - 0xB7)
+ return String, size, err
+ case b < 0xF8:
+ // If the total payload of a list
+ // (i.e. the combined length of all its items) is 0-55 bytes long, the
+ // RLP encoding consists of a single byte with value 0xC0 plus the length
+ // of the list followed by the concatenation of the RLP encodings of the
+ // items. The range of the first byte is thus [0xC0, 0xF7].
+ return List, uint64(b - 0xC0), nil
+ default:
+ // If the total payload of a list is more than 55 bytes long,
+ // the RLP encoding consists of a single byte with value 0xF7
+ // plus the length of the length of the payload in binary
+ // form, followed by the length of the payload, followed by
+ // the concatenation of the RLP encodings of the items. The
+ // range of the first byte is thus [0xF8, 0xFF].
+ size, err = s.readUint(b - 0xF7)
+ return List, size, err
+ }
+}
+
+func (s *Stream) readUint(size byte) (uint64, error) {
+ if size == 1 {
+ b, err := s.readByte()
+ if err == io.EOF {
+ err = io.ErrUnexpectedEOF
+ }
+ return uint64(b), err
+ }
+ start := int(8 - size)
+ for i := 0; i < start; i++ {
+ s.uintbuf[i] = 0
+ }
+ err := s.readFull(s.uintbuf[start:])
+ return binary.BigEndian.Uint64(s.uintbuf), err
+}
+
+func (s *Stream) readFull(buf []byte) (err error) {
+ s.willRead(uint64(len(buf)))
+ var nn, n int
+ for n < len(buf) && err == nil {
+ nn, err = s.r.Read(buf[n:])
+ n += nn
+ }
+ if err == io.EOF {
+ err = io.ErrUnexpectedEOF
+ }
+ return err
+}
+
+func (s *Stream) readByte() (byte, error) {
+ s.willRead(1)
+ b, err := s.r.ReadByte()
+ if len(s.stack) > 0 && err == io.EOF {
+ err = io.ErrUnexpectedEOF
+ }
+ return b, err
+}
+
+func (s *Stream) willRead(n uint64) {
+ s.kind = -1 // rearm Kind
+ if len(s.stack) > 0 {
+ s.stack[len(s.stack)-1].pos += n
+ }
+}
diff --git a/rlp/decode_test.go b/rlp/decode_test.go
new file mode 100644
index 000000000..5cb42b870
--- /dev/null
+++ b/rlp/decode_test.go
@@ -0,0 +1,469 @@
+package rlp
+
+import (
+ "bytes"
+ "encoding/hex"
+ "errors"
+ "fmt"
+ "io"
+ "math/big"
+ "reflect"
+ "testing"
+
+ "github.com/ethereum/go-ethereum/ethutil"
+)
+
+func TestStreamKind(t *testing.T) {
+ tests := []struct {
+ input string
+ wantKind Kind
+ wantLen uint64
+ }{
+ {"00", Byte, 0},
+ {"01", Byte, 0},
+ {"7F", Byte, 0},
+ {"80", String, 0},
+ {"B7", String, 55},
+ {"B800", String, 0},
+ {"B90400", String, 1024},
+ {"BA000400", String, 1024},
+ {"BB00000400", String, 1024},
+ {"BFFFFFFFFFFFFFFFFF", String, ^uint64(0)},
+ {"C0", List, 0},
+ {"C8", List, 8},
+ {"F7", List, 55},
+ {"F800", List, 0},
+ {"F804", List, 4},
+ {"F90400", List, 1024},
+ {"FFFFFFFFFFFFFFFFFF", List, ^uint64(0)},
+ }
+
+ for i, test := range tests {
+ s := NewStream(bytes.NewReader(unhex(test.input)))
+ kind, len, err := s.Kind()
+ if err != nil {
+ t.Errorf("test %d: Type returned error: %v", i, err)
+ continue
+ }
+ if kind != test.wantKind {
+ t.Errorf("test %d: kind mismatch: got %d, want %d", i, kind, test.wantKind)
+ }
+ if len != test.wantLen {
+ t.Errorf("test %d: len mismatch: got %d, want %d", i, len, test.wantLen)
+ }
+ }
+}
+
+func TestStreamErrors(t *testing.T) {
+ type calls []string
+ tests := []struct {
+ string
+ calls
+ error
+ }{
+ {"", calls{"Kind"}, io.EOF},
+ {"", calls{"List"}, io.EOF},
+ {"", calls{"Uint"}, io.EOF},
+ {"C0", calls{"Bytes"}, ErrExpectedString},
+ {"C0", calls{"Uint"}, ErrExpectedString},
+ {"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")},
+ {"00", calls{"List"}, ErrExpectedList},
+ {"80", calls{"List"}, ErrExpectedList},
+ {"C0", calls{"List", "Uint"}, EOL},
+ {"C801", calls{"List", "Uint", "Uint"}, io.ErrUnexpectedEOF},
+ {"C8C9", calls{"List", "Kind"}, ErrElemTooLarge},
+ {"C3C2010201", calls{"List", "List", "Uint", "Uint", "ListEnd", "Uint"}, EOL},
+ {"00", calls{"ListEnd"}, errNotInList},
+ {"C40102", calls{"List", "Uint", "ListEnd"}, errNotAtEOL},
+ }
+
+testfor:
+ for i, test := range tests {
+ s := NewStream(bytes.NewReader(unhex(test.string)))
+ rs := reflect.ValueOf(s)
+ for j, call := range test.calls {
+ fval := rs.MethodByName(call)
+ ret := fval.Call(nil)
+ err := "<nil>"
+ if lastret := ret[len(ret)-1].Interface(); lastret != nil {
+ err = lastret.(error).Error()
+ }
+ if j == len(test.calls)-1 {
+ if err != test.error.Error() {
+ t.Errorf("test %d: last call (%s) error mismatch\ngot: %s\nwant: %v",
+ i, call, err, test.error)
+ }
+ } else if err != "<nil>" {
+ t.Errorf("test %d: call %d (%s) unexpected error: %q", i, j, call, err)
+ continue testfor
+ }
+ }
+ }
+}
+
+func TestStreamList(t *testing.T) {
+ s := NewStream(bytes.NewReader(unhex("C80102030405060708")))
+
+ len, err := s.List()
+ if err != nil {
+ t.Fatalf("List error: %v", err)
+ }
+ if len != 8 {
+ t.Fatalf("List returned invalid length, got %d, want 8", len)
+ }
+
+ for i := uint64(1); i <= 8; i++ {
+ v, err := s.Uint()
+ if err != nil {
+ t.Fatalf("Uint error: %v", err)
+ }
+ if i != v {
+ t.Errorf("Uint returned wrong value, got %d, want %d", v, i)
+ }
+ }
+
+ if _, err := s.Uint(); err != EOL {
+ t.Errorf("Uint error mismatch, got %v, want %v", err, EOL)
+ }
+ if err = s.ListEnd(); err != nil {
+ t.Fatalf("ListEnd error: %v", err)
+ }
+}
+
+func TestDecodeErrors(t *testing.T) {
+ r := bytes.NewReader(nil)
+
+ if err := Decode(r, nil); err != errDecodeIntoNil {
+ t.Errorf("Decode(r, nil) error mismatch, got %q, want %q", err, errDecodeIntoNil)
+ }
+
+ var nilptr *struct{}
+ if err := Decode(r, nilptr); err != errDecodeIntoNil {
+ t.Errorf("Decode(r, nilptr) error mismatch, got %q, want %q", err, errDecodeIntoNil)
+ }
+
+ if err := Decode(r, struct{}{}); err != errNoPointer {
+ t.Errorf("Decode(r, struct{}{}) error mismatch, got %q, want %q", err, errNoPointer)
+ }
+
+ expectErr := "rlp: type chan bool is not RLP-serializable"
+ if err := Decode(r, new(chan bool)); err == nil || err.Error() != expectErr {
+ t.Errorf("Decode(r, new(chan bool)) error mismatch, got %q, want %q", err, expectErr)
+ }
+
+ if err := Decode(r, new(int)); err != io.EOF {
+ t.Errorf("Decode(r, new(int)) error mismatch, got %q, want %q", err, io.EOF)
+ }
+}
+
+type decodeTest struct {
+ input string
+ ptr interface{}
+ value interface{}
+ error error
+}
+
+type simplestruct struct {
+ A int
+ B string
+}
+
+type recstruct struct {
+ I int
+ Child *recstruct
+}
+
+var sharedByteArray [5]byte
+
+var (
+ veryBigInt = big.NewInt(0).Add(
+ big.NewInt(0).Lsh(big.NewInt(0xFFFFFFFFFFFFFF), 16),
+ big.NewInt(0xFFFF),
+ )
+)
+
+var decodeTests = []decodeTest{
+ // integers
+ {input: "05", ptr: new(uint32), value: uint32(5)},
+ {input: "80", ptr: new(uint32), value: uint32(0)},
+ {input: "8105", ptr: new(uint32), value: uint32(5)},
+ {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},
+
+ // slices
+ {input: "C0", ptr: new([]int), value: []int{}},
+ {input: "C80102030405060708", ptr: new([]int), value: []int{1, 2, 3, 4, 5, 6, 7, 8}},
+
+ // 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")},
+
+ // 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")},
+
+ // 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},
+
+ // byte array reuse (should be zeroed)
+ {input: "850102030405", ptr: &sharedByteArray, value: [5]byte{1, 2, 3, 4, 5}},
+ {input: "8101", ptr: &sharedByteArray, value: [5]byte{1}}, // kind: String
+ {input: "850102030405", ptr: &sharedByteArray, value: [5]byte{1, 2, 3, 4, 5}},
+ {input: "01", ptr: &sharedByteArray, value: [5]byte{1}}, // kind: Byte
+ {input: "C3010203", ptr: &sharedByteArray, value: [5]byte{1, 2, 3, 0, 0}},
+ {input: "C101", ptr: &sharedByteArray, value: [5]byte{1}}, // kind: List
+
+ // 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},
+
+ // strings
+ {input: "00", ptr: new(string), value: "\000"},
+ {input: "8D6162636465666768696A6B6C6D", ptr: new(string), value: "abcdefghijklm"},
+ {input: "C0", ptr: new(string), error: ErrExpectedString},
+
+ // 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},
+
+ // 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: "C501C302C103",
+ ptr: new(recstruct),
+ value: recstruct{1, &recstruct{2, &recstruct{3, nil}}},
+ },
+
+ // pointers
+ {input: "00", ptr: new(*int), value: (*int)(nil)},
+ {input: "80", ptr: new(*int), value: (*int)(nil)},
+ {input: "C0", ptr: new(*int), value: (*int)(nil)},
+ {input: "07", ptr: new(*int), value: intp(7)},
+ {input: "8108", ptr: new(*int), value: intp(8)},
+ {input: "C109", ptr: new(*[]int), value: &[]int{9}},
+ {input: "C58403030303", ptr: new(*[][]byte), value: &[][]byte{{3, 3, 3, 3}}},
+
+ // interface{}
+ {input: "00", ptr: new(interface{}), value: []byte{0}},
+ {input: "01", ptr: new(interface{}), value: []byte{1}},
+ {input: "80", ptr: new(interface{}), value: []byte{}},
+ {input: "850505050505", ptr: new(interface{}), value: []byte{5, 5, 5, 5, 5}},
+ {input: "C0", ptr: new(interface{}), value: []interface{}{}},
+ {input: "C50183040404", ptr: new(interface{}), value: []interface{}{[]byte{1}, []byte{4, 4, 4}}},
+}
+
+func intp(i int) *int { return &i }
+
+func TestDecode(t *testing.T) {
+ for i, test := range decodeTests {
+ input, err := hex.DecodeString(test.input)
+ if err != nil {
+ t.Errorf("test %d: invalid hex input %q", i, test.input)
+ continue
+ }
+ err = Decode(bytes.NewReader(input), test.ptr)
+ if err != nil && test.error == nil {
+ 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) {
+ 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
+ }
+ deref := reflect.ValueOf(test.ptr).Elem().Interface()
+ if err == nil && !reflect.DeepEqual(deref, test.value) {
+ t.Errorf("test %d: value mismatch\ngot %#v\nwant %#v\ndecoding into %T\ninput %q",
+ i, deref, test.value, test.ptr, test.input)
+ }
+ }
+}
+
+type testDecoder struct{ called bool }
+
+func (t *testDecoder) DecodeRLP(s *Stream) error {
+ if _, err := s.Uint(); err != nil {
+ return err
+ }
+ t.called = true
+ return nil
+}
+
+func TestDecodeDecoder(t *testing.T) {
+ var s struct {
+ T1 testDecoder
+ T2 *testDecoder
+ T3 **testDecoder
+ }
+ if err := Decode(bytes.NewReader(unhex("C3010203")), &s); err != nil {
+ t.Fatalf("Decode error: %v", err)
+ }
+
+ if !s.T1.called {
+ t.Errorf("DecodeRLP was not called for (non-pointer) testDecoder")
+ }
+
+ if s.T2 == nil {
+ t.Errorf("*testDecoder has not been allocated")
+ } else if !s.T2.called {
+ t.Errorf("DecodeRLP was not called for *testDecoder")
+ }
+
+ if s.T3 == nil || *s.T3 == nil {
+ t.Errorf("**testDecoder has not been allocated")
+ } else if !(*s.T3).called {
+ t.Errorf("DecodeRLP was not called for **testDecoder")
+ }
+}
+
+type byteDecoder byte
+
+func (bd *byteDecoder) DecodeRLP(s *Stream) error {
+ _, err := s.Uint()
+ *bd = 255
+ return err
+}
+
+func (bd byteDecoder) called() bool {
+ return bd == 255
+}
+
+// This test verifies that the byte slice/byte array logic
+// does not kick in for element types implementing Decoder.
+func TestDecoderInByteSlice(t *testing.T) {
+ var slice []byteDecoder
+ if err := Decode(bytes.NewReader(unhex("C101")), &slice); err != nil {
+ t.Errorf("unexpected Decode error %v", err)
+ } else if !slice[0].called() {
+ t.Errorf("DecodeRLP not called for slice element")
+ }
+
+ var array [1]byteDecoder
+ if err := Decode(bytes.NewReader(unhex("C101")), &array); err != nil {
+ t.Errorf("unexpected Decode error %v", err)
+ } else if !array[0].called() {
+ t.Errorf("DecodeRLP not called for array element")
+ }
+}
+
+func ExampleDecode() {
+ input, _ := hex.DecodeString("C90A1486666F6F626172")
+
+ type example struct {
+ A, B int
+ private int // private fields are ignored
+ String string
+ }
+
+ var s example
+ err := Decode(bytes.NewReader(input), &s)
+ if err != nil {
+ fmt.Printf("Error: %v\n", err)
+ } else {
+ fmt.Printf("Decoded value: %#v\n", s)
+ }
+ // Output:
+ // Decoded value: rlp.example{A:10, B:20, private:0, String:"foobar"}
+}
+
+func ExampleStream() {
+ input, _ := hex.DecodeString("C90A1486666F6F626172")
+ s := NewStream(bytes.NewReader(input))
+
+ // Check what kind of value lies ahead
+ kind, size, _ := s.Kind()
+ fmt.Printf("Kind: %v size:%d\n", kind, size)
+
+ // Enter the list
+ if _, err := s.List(); err != nil {
+ fmt.Printf("List error: %v\n", err)
+ return
+ }
+
+ // Decode elements
+ fmt.Println(s.Uint())
+ fmt.Println(s.Uint())
+ fmt.Println(s.Bytes())
+
+ // Acknowledge end of list
+ if err := s.ListEnd(); err != nil {
+ fmt.Printf("ListEnd error: %v\n", err)
+ }
+ // Output:
+ // Kind: List size:9
+ // 10 <nil>
+ // 20 <nil>
+ // [102 111 111 98 97 114] <nil>
+}
+
+func BenchmarkDecode(b *testing.B) {
+ enc := encTest(90000)
+ b.SetBytes(int64(len(enc)))
+ b.ReportAllocs()
+ b.ResetTimer()
+
+ for i := 0; i < b.N; i++ {
+ var s []int
+ r := bytes.NewReader(enc)
+ if err := Decode(r, &s); err != nil {
+ b.Fatalf("Decode error: %v", err)
+ }
+ }
+}
+
+func BenchmarkDecodeIntSliceReuse(b *testing.B) {
+ enc := encTest(100000)
+ b.SetBytes(int64(len(enc)))
+ b.ReportAllocs()
+ b.ResetTimer()
+
+ var s []int
+ for i := 0; i < b.N; i++ {
+ r := bytes.NewReader(enc)
+ if err := Decode(r, &s); err != nil {
+ b.Fatalf("Decode error: %v", err)
+ }
+ }
+}
+
+func encTest(n int) []byte {
+ s := make([]interface{}, n)
+ for i := 0; i < n; i++ {
+ s[i] = i
+ }
+ return ethutil.Encode(s)
+}
+
+func unhex(str string) []byte {
+ b, err := hex.DecodeString(str)
+ if err != nil {
+ panic(fmt.Sprintf("invalid hex string: %q", str))
+ }
+ return b
+}
diff --git a/rlp/doc.go b/rlp/doc.go
new file mode 100644
index 000000000..aab98ea43
--- /dev/null
+++ b/rlp/doc.go
@@ -0,0 +1,17 @@
+/*
+Package rlp implements the RLP serialization format.
+
+The purpose of RLP (Recursive Linear Prefix) qis to encode arbitrarily
+nested arrays of binary data, and RLP is the main encoding method used
+to serialize objects in Ethereum. The only purpose of RLP is to encode
+structure; encoding specific atomic data types (eg. strings, ints,
+floats) is left up to higher-order protocols; in Ethereum integers
+must be represented in big endian binary form with no leading zeroes
+(thus making the integer value zero be equivalent to the empty byte
+array).
+
+RLP values are distinguished by a type tag. The type tag precedes the
+value in the input stream and defines the size and kind of the bytes
+that follow.
+*/
+package rlp
diff --git a/rlp/typecache.go b/rlp/typecache.go
new file mode 100644
index 000000000..75dbb43c2
--- /dev/null
+++ b/rlp/typecache.go
@@ -0,0 +1,91 @@
+package rlp
+
+import (
+ "fmt"
+ "math/big"
+ "reflect"
+ "sync"
+)
+
+type decoder func(*Stream, reflect.Value) error
+
+type typeinfo struct {
+ decoder
+}
+
+var (
+ typeCacheMutex sync.RWMutex
+ typeCache = make(map[reflect.Type]*typeinfo)
+)
+
+func cachedTypeInfo(typ reflect.Type) (*typeinfo, error) {
+ typeCacheMutex.RLock()
+ info := typeCache[typ]
+ typeCacheMutex.RUnlock()
+ if info != nil {
+ return info, nil
+ }
+ // not in the cache, need to generate info for this type.
+ typeCacheMutex.Lock()
+ defer typeCacheMutex.Unlock()
+ return cachedTypeInfo1(typ)
+}
+
+func cachedTypeInfo1(typ reflect.Type) (*typeinfo, error) {
+ info := typeCache[typ]
+ if info != nil {
+ // another goroutine got the write lock first
+ return info, nil
+ }
+ // put a dummmy value into the cache before generating.
+ // if the generator tries to lookup itself, it will get
+ // the dummy value and won't call itself recursively.
+ typeCache[typ] = new(typeinfo)
+ info, err := genTypeInfo(typ)
+ if err != nil {
+ // remove the dummy value if the generator fails
+ delete(typeCache, typ)
+ return nil, err
+ }
+ *typeCache[typ] = *info
+ return typeCache[typ], err
+}
+
+var (
+ decoderInterface = reflect.TypeOf(new(Decoder)).Elem()
+ bigInt = reflect.TypeOf(big.Int{})
+)
+
+func genTypeInfo(typ reflect.Type) (info *typeinfo, err error) {
+ info = new(typeinfo)
+ kind := typ.Kind()
+ switch {
+ case typ.Implements(decoderInterface):
+ info.decoder = decodeDecoder
+ case kind != reflect.Ptr && reflect.PtrTo(typ).Implements(decoderInterface):
+ info.decoder = decodeDecoderNoPtr
+ case typ.AssignableTo(reflect.PtrTo(bigInt)):
+ info.decoder = decodeBigInt
+ case typ.AssignableTo(bigInt):
+ info.decoder = decodeBigIntNoPtr
+ case isInteger(kind):
+ info.decoder = makeNumDecoder(typ)
+ case kind == reflect.String:
+ info.decoder = decodeString
+ case kind == reflect.Slice || kind == reflect.Array:
+ info.decoder, err = makeListDecoder(typ)
+ case kind == reflect.Struct:
+ info.decoder, err = makeStructDecoder(typ)
+ case kind == reflect.Ptr:
+ info.decoder, err = makePtrDecoder(typ)
+ case kind == reflect.Interface && typ.NumMethod() == 0:
+ info.decoder = decodeInterface
+ default:
+ err = fmt.Errorf("rlp: type %v is not RLP-serializable", typ)
+ }
+ return info, err
+}
+
+func isInteger(k reflect.Kind) bool {
+ return k >= reflect.Int && k <= reflect.Uintptr
+}
--
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