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()),
174 v.SetString(d.buf.String())
177 if v.Type().Elem().Kind() != reflect.Uint8 {
180 v.SetBytes(append([]byte(nil), d.buf.Bytes()...))
183 if v.Type().Elem().Kind() != reflect.Uint8 {
186 reflect.Copy(v, reflect.ValueOf(d.buf.Bytes()))
189 // I believe we return here to support "ignore_unmarshal_type_error".
190 return &UnmarshalTypeError{
196 // Info for parsing a dict value.
197 type dictField struct {
198 Value reflect.Value // Storage for the parsed value.
199 // True if field value should be parsed into Value. If false, the value
200 // should be parsed and discarded.
202 Set func() // Call this after parsing into Value.
203 IgnoreUnmarshalTypeError bool
206 // Returns specifics for parsing a dict field value.
207 func getDictField(dict reflect.Value, key string) dictField {
208 // get valuev as a map value or as a struct field
211 value := reflect.New(dict.Type().Elem()).Elem()
216 // Assigns the value into the map.
217 dict.SetMapIndex(reflect.ValueOf(key).Convert(dict.Type().Key()), value)
221 sf, ok := getStructFieldForKey(dict.Type(), key)
225 if sf.PkgPath != "" {
226 panic(&UnmarshalFieldError{
233 Value: dict.FieldByIndex(sf.Index),
236 IgnoreUnmarshalTypeError: getTag(sf.Tag).IgnoreUnmarshalTypeError(),
243 func getStructFieldForKey(struct_ reflect.Type, key string) (f reflect.StructField, ok bool) {
244 for i, n := 0, struct_.NumField(); i < n; i++ {
246 tag := f.Tag.Get("bencode")
254 if parseTag(tag).Key() == key {
264 if strings.EqualFold(f.Name, key) {
272 func (d *Decoder) parseDict(v reflect.Value) error {
276 if t.Key().Kind() != reflect.String {
277 panic(&UnmarshalTypeError{
283 v.Set(reflect.MakeMap(t))
287 panic(&UnmarshalTypeError{
293 // so, at this point 'd' byte was consumed, let's just read key/value
297 keyValue := reflect.ValueOf(&keyStr).Elem()
298 ok, err := d.parseValue(keyValue)
300 return fmt.Errorf("error parsing dict key: %s", err)
306 df := getDictField(v, keyStr)
308 // now we need to actually parse it
310 // log.Printf("parsing ok struct field for key %q", keyStr)
311 ok, err = d.parseValue(df.Value)
313 // Discard the value, there's nowhere to put it.
315 if_, ok = d.parseValueInterface()
317 err = fmt.Errorf("error parsing value for key %q", keyStr)
321 if _, ok := err.(*UnmarshalTypeError); !ok || !df.IgnoreUnmarshalTypeError {
322 return fmt.Errorf("parsing value for key %q: %s", keyStr, err)
326 return fmt.Errorf("missing value for key %q", keyStr)
334 func (d *Decoder) parseList(v reflect.Value) error {
336 case reflect.Array, reflect.Slice:
338 panic(&UnmarshalTypeError{
346 if v.Kind() == reflect.Slice && i >= v.Len() {
347 v.Set(reflect.Append(v, reflect.Zero(v.Type().Elem())))
351 ok, err := d.parseValue(v.Index(i))
359 _, ok := d.parseValueInterface()
367 if v.Kind() == reflect.Array {
368 z := reflect.Zero(v.Type().Elem())
369 for n := v.Len(); i < n; i++ {
377 if i == 0 && v.Kind() == reflect.Slice {
378 v.Set(reflect.MakeSlice(v.Type(), 0, 0))
383 func (d *Decoder) readOneValue() bool {
384 b, err := d.r.ReadByte()
398 // read until there is nothing to read
399 for d.readOneValue() {
401 // consume 'e' as well
406 d.buf.WriteString("e")
408 if b >= '0' && b <= '9' {
409 start := d.buf.Len() - 1
411 s := reflect.StringHeader{
412 uintptr(unsafe.Pointer(&d.buf.Bytes()[start])),
415 length, err := strconv.ParseInt(*(*string)(unsafe.Pointer(&s)), 10, 64)
416 checkForIntParseError(err, d.Offset-1)
418 d.buf.WriteString(":")
419 n, err := io.CopyN(&d.buf, d.r, length)
422 checkForUnexpectedEOF(err, d.Offset)
425 What: errors.New("unexpected I/O error: " + err.Error()),
431 d.raiseUnknownValueType(b, d.Offset-1)
438 func (d *Decoder) parseUnmarshaler(v reflect.Value) bool {
439 m, ok := v.Interface().(Unmarshaler)
441 // T doesn't work, try *T
442 if v.Kind() != reflect.Ptr && v.CanAddr() {
443 m, ok = v.Addr().Interface().(Unmarshaler)
449 if ok && (v.Kind() != reflect.Ptr || !v.IsNil()) {
450 if d.readOneValue() {
451 err := m.UnmarshalBencode(d.buf.Bytes())
454 panic(&UnmarshalerError{v.Type(), err})
464 // Returns true if there was a value and it's now stored in 'v', otherwise
465 // there was an end symbol ("e") and no value was stored.
466 func (d *Decoder) parseValue(v reflect.Value) (bool, error) {
467 // we support one level of indirection at the moment
468 if v.Kind() == reflect.Ptr {
469 // if the pointer is nil, allocate a new element of the type it
472 v.Set(reflect.New(v.Type().Elem()))
477 if d.parseUnmarshaler(v) {
481 // common case: interface{}
482 if v.Kind() == reflect.Interface && v.NumMethod() == 0 {
483 iface, _ := d.parseValueInterface()
484 v.Set(reflect.ValueOf(iface))
488 b, err := d.r.ReadByte()
498 return true, d.parseDict(v)
500 return true, d.parseList(v)
505 if b >= '0' && b <= '9' {
508 // Write the first digit of the length to the buffer.
510 return true, d.parseString(v)
513 d.raiseUnknownValueType(b, d.Offset-1)
518 // An unknown bencode type character was encountered.
519 func (d *Decoder) raiseUnknownValueType(b byte, offset int64) {
522 What: fmt.Errorf("unknown value type %+q", b),
526 func (d *Decoder) parseValueInterface() (interface{}, bool) {
527 b, err := d.r.ReadByte()
537 return d.parseDictInterface(), true
539 return d.parseListInterface(), true
541 return d.parseIntInterface(), true
543 if b >= '0' && b <= '9' {
545 // append first digit of the length to the buffer
547 return d.parseStringInterface(), true
550 d.raiseUnknownValueType(b, d.Offset-1)
555 func (d *Decoder) parseIntInterface() (ret interface{}) {
556 start := d.Offset - 1
558 if d.buf.Len() == 0 {
561 What: errors.New("empty integer value"),
565 n, err := strconv.ParseInt(d.buf.String(), 10, 64)
566 if ne, ok := err.(*strconv.NumError); ok && ne.Err == strconv.ErrRange {
568 _, ok := i.SetString(d.buf.String(), 10)
572 What: errors.New("failed to parse integer"),
577 checkForIntParseError(err, start)
585 func (d *Decoder) parseStringInterface() interface{} {
586 start := d.Offset - 1
588 // read the string length first
590 length, err := strconv.ParseInt(d.buf.String(), 10, 64)
591 checkForIntParseError(err, start)
594 n, err := io.CopyN(&d.buf, d.r, length)
597 checkForUnexpectedEOF(err, d.Offset)
600 What: errors.New("unexpected I/O error: " + err.Error()),
609 func (d *Decoder) parseDictInterface() interface{} {
610 dict := make(map[string]interface{})
612 keyi, ok := d.parseValueInterface()
617 key, ok := keyi.(string)
621 What: errors.New("non-string key in a dict"),
625 valuei, ok := d.parseValueInterface()
635 func (d *Decoder) parseListInterface() interface{} {
636 var list []interface{}
638 valuei, ok := d.parseValueInterface()
643 list = append(list, valuei)
646 list = make([]interface{}, 0, 0)