21 // Sum of bytes used to Decode values.
26 func (d *Decoder) Decode(v interface{}) (err error) {
32 _, ok := r.(runtime.Error)
42 pv := reflect.ValueOf(v)
43 if pv.Kind() != reflect.Ptr || pv.IsNil() {
44 return &UnmarshalInvalidArgError{reflect.TypeOf(v)}
47 ok, err := d.parseValue(pv.Elem())
52 d.throwSyntaxError(d.Offset-1, errors.New("unexpected 'e'"))
57 func checkForUnexpectedEOF(err error, offset int64) {
61 What: io.ErrUnexpectedEOF,
66 func (d *Decoder) readByte() byte {
67 b, err := d.r.ReadByte()
69 checkForUnexpectedEOF(err, d.Offset)
77 // reads data writing it to 'd.buf' until 'sep' byte is encountered, 'sep' byte
78 // is consumed, but not included into the 'd.buf'
79 func (d *Decoder) readUntil(sep byte) {
89 func checkForIntParseError(err error, offset int64) {
98 func (d *Decoder) throwSyntaxError(offset int64, err error) {
105 // called when 'i' was consumed
106 func (d *Decoder) parseInt(v reflect.Value) {
107 start := d.Offset - 1
109 if d.buf.Len() == 0 {
112 What: errors.New("empty integer value"),
119 case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
120 n, err := strconv.ParseInt(s, 10, 64)
121 checkForIntParseError(err, start)
123 if v.OverflowInt(n) {
124 panic(&UnmarshalTypeError{
125 Value: "integer " + s,
130 case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
131 n, err := strconv.ParseUint(s, 10, 64)
132 checkForIntParseError(err, start)
134 if v.OverflowUint(n) {
135 panic(&UnmarshalTypeError{
136 Value: "integer " + s,
144 panic(&UnmarshalTypeError{
145 Value: "integer " + s,
152 func (d *Decoder) parseString(v reflect.Value) error {
153 start := d.Offset - 1
155 // read the string length first
157 length, err := strconv.ParseInt(d.buf.String(), 10, 64)
158 checkForIntParseError(err, start)
161 n, err := io.CopyN(&d.buf, d.r, length)
164 checkForUnexpectedEOF(err, d.Offset)
167 What: errors.New("unexpected I/O error: " + err.Error()),
173 v.SetString(d.buf.String())
175 if v.Type().Elem().Kind() != reflect.Uint8 {
176 panic(&UnmarshalTypeError{
181 v.SetBytes(append([]byte(nil), d.buf.Bytes()...))
183 return &UnmarshalTypeError{
193 // Info for parsing a dict value.
194 type dictField struct {
195 Value reflect.Value // Storage for the parsed value.
196 // True if field value should be parsed into Value. If false, the value
197 // should be parsed and discarded.
199 Set func() // Call this after parsing into Value.
200 IgnoreUnmarshalTypeError bool
203 // Returns specifics for parsing a dict field value.
204 func getDictField(dict reflect.Value, key string) dictField {
205 // get valuev as a map value or as a struct field
208 value := reflect.New(dict.Type().Elem()).Elem()
213 // Assigns the value into the map.
214 dict.SetMapIndex(reflect.ValueOf(key), value)
218 sf, ok := getStructFieldForKey(dict.Type(), key)
222 if sf.PkgPath != "" {
223 panic(&UnmarshalFieldError{
230 Value: dict.FieldByIndex(sf.Index),
233 IgnoreUnmarshalTypeError: getTag(sf.Tag).IgnoreUnmarshalTypeError(),
240 func getStructFieldForKey(struct_ reflect.Type, key string) (f reflect.StructField, ok bool) {
241 for i, n := 0, struct_.NumField(); i < n; i++ {
243 tag := f.Tag.Get("bencode")
251 if parseTag(tag).Key() == key {
261 if strings.EqualFold(f.Name, key) {
269 func (d *Decoder) parseDict(v reflect.Value) error {
273 if t.Key().Kind() != reflect.String {
274 panic(&UnmarshalTypeError{
280 v.Set(reflect.MakeMap(t))
284 panic(&UnmarshalTypeError{
290 // so, at this point 'd' byte was consumed, let's just read key/value
294 keyValue := reflect.ValueOf(&keyStr).Elem()
295 ok, err := d.parseValue(keyValue)
297 return fmt.Errorf("error parsing dict key: %s", err)
303 df := getDictField(v, keyStr)
305 // now we need to actually parse it
307 // log.Printf("parsing ok struct field for key %q", keyStr)
308 ok, err = d.parseValue(df.Value)
310 // Discard the value, there's nowhere to put it.
312 if_, ok = d.parseValueInterface()
314 err = fmt.Errorf("error parsing value for key %q", keyStr)
318 if _, ok := err.(*UnmarshalTypeError); !ok || !df.IgnoreUnmarshalTypeError {
319 return fmt.Errorf("parsing value for key %q: %s", keyStr, err)
323 return fmt.Errorf("missing value for key %q", keyStr)
331 func (d *Decoder) parseList(v reflect.Value) error {
333 case reflect.Array, reflect.Slice:
335 panic(&UnmarshalTypeError{
343 if v.Kind() == reflect.Slice && i >= v.Len() {
344 v.Set(reflect.Append(v, reflect.Zero(v.Type().Elem())))
348 ok, err := d.parseValue(v.Index(i))
356 _, ok := d.parseValueInterface()
364 if v.Kind() == reflect.Array {
365 z := reflect.Zero(v.Type().Elem())
366 for n := v.Len(); i < n; i++ {
374 if i == 0 && v.Kind() == reflect.Slice {
375 v.Set(reflect.MakeSlice(v.Type(), 0, 0))
380 func (d *Decoder) readOneValue() bool {
381 b, err := d.r.ReadByte()
395 // read until there is nothing to read
396 for d.readOneValue() {
398 // consume 'e' as well
403 d.buf.WriteString("e")
405 if b >= '0' && b <= '9' {
406 start := d.buf.Len() - 1
408 s := reflect.StringHeader{
409 uintptr(unsafe.Pointer(&d.buf.Bytes()[start])),
412 length, err := strconv.ParseInt(*(*string)(unsafe.Pointer(&s)), 10, 64)
413 checkForIntParseError(err, d.Offset-1)
415 d.buf.WriteString(":")
416 n, err := io.CopyN(&d.buf, d.r, length)
419 checkForUnexpectedEOF(err, d.Offset)
422 What: errors.New("unexpected I/O error: " + err.Error()),
428 d.raiseUnknownValueType(b, d.Offset-1)
435 func (d *Decoder) parseUnmarshaler(v reflect.Value) bool {
436 m, ok := v.Interface().(Unmarshaler)
438 // T doesn't work, try *T
439 if v.Kind() != reflect.Ptr && v.CanAddr() {
440 m, ok = v.Addr().Interface().(Unmarshaler)
446 if ok && (v.Kind() != reflect.Ptr || !v.IsNil()) {
447 if d.readOneValue() {
448 err := m.UnmarshalBencode(d.buf.Bytes())
451 panic(&UnmarshalerError{v.Type(), err})
461 // Returns true if there was a value and it's now stored in 'v', otherwise
462 // there was an end symbol ("e") and no value was stored.
463 func (d *Decoder) parseValue(v reflect.Value) (bool, error) {
464 // we support one level of indirection at the moment
465 if v.Kind() == reflect.Ptr {
466 // if the pointer is nil, allocate a new element of the type it
469 v.Set(reflect.New(v.Type().Elem()))
474 if d.parseUnmarshaler(v) {
478 // common case: interface{}
479 if v.Kind() == reflect.Interface && v.NumMethod() == 0 {
480 iface, _ := d.parseValueInterface()
481 v.Set(reflect.ValueOf(iface))
485 b, err := d.r.ReadByte()
495 return true, d.parseDict(v)
497 return true, d.parseList(v)
502 if b >= '0' && b <= '9' {
505 // Write the first digit of the length to the buffer.
507 return true, d.parseString(v)
510 d.raiseUnknownValueType(b, d.Offset-1)
515 // An unknown bencode type character was encountered.
516 func (d *Decoder) raiseUnknownValueType(b byte, offset int64) {
519 What: fmt.Errorf("unknown value type %+q", b),
523 func (d *Decoder) parseValueInterface() (interface{}, bool) {
524 b, err := d.r.ReadByte()
534 return d.parseDictInterface(), true
536 return d.parseListInterface(), true
538 return d.parseIntInterface(), true
540 if b >= '0' && b <= '9' {
542 // append first digit of the length to the buffer
544 return d.parseStringInterface(), true
547 d.raiseUnknownValueType(b, d.Offset-1)
552 func (d *Decoder) parseIntInterface() (ret interface{}) {
553 start := d.Offset - 1
555 if d.buf.Len() == 0 {
558 What: errors.New("empty integer value"),
562 n, err := strconv.ParseInt(d.buf.String(), 10, 64)
563 if ne, ok := err.(*strconv.NumError); ok && ne.Err == strconv.ErrRange {
565 _, ok := i.SetString(d.buf.String(), 10)
569 What: errors.New("failed to parse integer"),
574 checkForIntParseError(err, start)
582 func (d *Decoder) parseStringInterface() interface{} {
583 start := d.Offset - 1
585 // read the string length first
587 length, err := strconv.ParseInt(d.buf.String(), 10, 64)
588 checkForIntParseError(err, start)
591 n, err := io.CopyN(&d.buf, d.r, length)
594 checkForUnexpectedEOF(err, d.Offset)
597 What: errors.New("unexpected I/O error: " + err.Error()),
606 func (d *Decoder) parseDictInterface() interface{} {
607 dict := make(map[string]interface{})
609 keyi, ok := d.parseValueInterface()
614 key, ok := keyi.(string)
618 What: errors.New("non-string key in a dict"),
622 valuei, ok := d.parseValueInterface()
632 func (d *Decoder) parseListInterface() interface{} {
633 var list []interface{}
635 valuei, ok := d.parseValueInterface()
640 list = append(list, valuei)
643 list = make([]interface{}, 0, 0)