20 // Sum of bytes used to Decode values.
25 func (d *Decoder) Decode(v interface{}) (err error) {
31 _, ok := r.(runtime.Error)
41 pv := reflect.ValueOf(v)
42 if pv.Kind() != reflect.Ptr || pv.IsNil() {
43 return &UnmarshalInvalidArgError{reflect.TypeOf(v)}
46 ok, err := d.parseValue(pv.Elem())
51 d.throwSyntaxError(d.Offset-1, errors.New("unexpected 'e'"))
56 func checkForUnexpectedEOF(err error, offset int64) {
60 What: io.ErrUnexpectedEOF,
65 func (d *Decoder) readByte() byte {
66 b, err := d.r.ReadByte()
68 checkForUnexpectedEOF(err, d.Offset)
76 // reads data writing it to 'd.buf' until 'sep' byte is encountered, 'sep' byte
77 // is consumed, but not included into the 'd.buf'
78 func (d *Decoder) readUntil(sep byte) {
88 func checkForIntParseError(err error, offset int64) {
97 func (d *Decoder) throwSyntaxError(offset int64, err error) {
104 // called when 'i' was consumed
105 func (d *Decoder) parseInt(v reflect.Value) {
106 start := d.Offset - 1
108 if d.buf.Len() == 0 {
111 What: errors.New("empty integer value"),
115 s := bytesAsString(d.buf.Bytes())
118 case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
119 n, err := strconv.ParseInt(s, 10, 64)
120 checkForIntParseError(err, start)
122 if v.OverflowInt(n) {
123 panic(&UnmarshalTypeError{
124 Value: "integer " + s,
129 case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
130 n, err := strconv.ParseUint(s, 10, 64)
131 checkForIntParseError(err, start)
133 if v.OverflowUint(n) {
134 panic(&UnmarshalTypeError{
135 Value: "integer " + s,
143 panic(&UnmarshalTypeError{
144 Value: "integer " + s,
151 func (d *Decoder) parseString(v reflect.Value) error {
152 start := d.Offset - 1
154 // read the string length first
156 length, err := strconv.ParseInt(bytesAsString(d.buf.Bytes()), 10, 0)
157 checkForIntParseError(err, start)
161 read := func(b []byte) {
162 n, err := io.ReadFull(d.r, b)
165 checkForUnexpectedEOF(err, d.Offset)
168 What: errors.New("unexpected I/O error: " + err.Error()),
175 b := make([]byte, length)
177 v.SetString(bytesAsString(b))
180 if v.Type().Elem().Kind() != reflect.Uint8 {
183 b := make([]byte, length)
188 if v.Type().Elem().Kind() != reflect.Uint8 {
191 d.buf.Grow(int(length))
192 b := d.buf.Bytes()[:length]
194 reflect.Copy(v, reflect.ValueOf(b))
197 d.buf.Grow(int(length))
198 read(d.buf.Bytes()[:length])
199 // I believe we return here to support "ignore_unmarshal_type_error".
200 return &UnmarshalTypeError{
206 // Info for parsing a dict value.
207 type dictField struct {
209 Get func(value reflect.Value) func(reflect.Value)
213 // Returns specifics for parsing a dict field value.
214 func getDictField(dict reflect.Type, key string) dictField {
215 // get valuev as a map value or as a struct field
220 Get: func(mapValue reflect.Value) func(reflect.Value) {
221 return func(value reflect.Value) {
222 if mapValue.IsNil() {
223 mapValue.Set(reflect.MakeMap(dict))
225 // Assigns the value into the map.
226 //log.Printf("map type: %v", mapValue.Type())
227 mapValue.SetMapIndex(reflect.ValueOf(key).Convert(dict.Key()), value)
232 return getStructFieldForKey(dict, key)
233 //if sf.r.PkgPath != "" {
234 // panic(&UnmarshalFieldError{
236 // Type: dict.Type(),
241 panic("unimplemented")
247 structFieldsMu sync.Mutex
248 structFields = map[reflect.Type]map[string]dictField{}
251 func parseStructFields(struct_ reflect.Type, each func(key string, df dictField)) {
252 for _i, n := 0, struct_.NumField(); _i < n; _i++ {
254 f := struct_.Field(i)
256 parseStructFields(f.Type.Elem(), func(key string, df dictField) {
258 df.Get = func(value reflect.Value) func(reflect.Value) {
259 anonPtr := value.Field(i)
261 anonPtr.Set(reflect.New(f.Type.Elem()))
263 return innerGet(anonPtr.Elem())
269 tagStr := f.Tag.Get("bencode")
273 tag := parseTag(tagStr)
278 each(key, dictField{f.Type, func(value reflect.Value) func(reflect.Value) {
279 return value.Field(i).Set
284 func saveStructFields(struct_ reflect.Type) {
285 m := make(map[string]dictField)
286 parseStructFields(struct_, func(key string, sf dictField) {
289 structFields[struct_] = m
292 func getStructFieldForKey(struct_ reflect.Type, key string) (f dictField) {
293 structFieldsMu.Lock()
294 if _, ok := structFields[struct_]; !ok {
295 saveStructFields(struct_)
297 f, ok := structFields[struct_][key]
298 structFieldsMu.Unlock()
300 var discard interface{}
302 Type: reflect.TypeOf(discard),
303 Get: func(reflect.Value) func(reflect.Value) { return func(reflect.Value) {} },
310 func (d *Decoder) parseDict(v reflect.Value) error {
311 // so, at this point 'd' byte was consumed, let's just read key/value
315 keyValue := reflect.ValueOf(&keyStr).Elem()
316 ok, err := d.parseValue(keyValue)
318 return fmt.Errorf("error parsing dict key: %s", err)
324 df := getDictField(v.Type(), keyStr)
326 // now we need to actually parse it
328 // Discard the value, there's nowhere to put it.
330 if_, ok = d.parseValueInterface()
332 return fmt.Errorf("error parsing value for key %q", keyStr)
335 return fmt.Errorf("missing value for key %q", keyStr)
339 setValue := reflect.New(df.Type).Elem()
340 //log.Printf("parsing into %v", setValue.Type())
341 ok, err = d.parseValue(setValue)
343 if _, ok := err.(*UnmarshalTypeError); !ok || !df.Tags.IgnoreUnmarshalTypeError() {
344 return fmt.Errorf("parsing value for key %q: %s", keyStr, err)
348 return fmt.Errorf("missing value for key %q", keyStr)
354 func (d *Decoder) parseList(v reflect.Value) error {
357 // If the list is a singleton of the expected type, use that value. See
358 // https://github.com/anacrolix/torrent/issues/297.
359 l := reflect.New(reflect.SliceOf(v.Type()))
360 if err := d.parseList(l.Elem()); err != nil {
363 if l.Elem().Len() != 1 {
364 return &UnmarshalTypeError{
369 v.Set(l.Elem().Index(0))
371 case reflect.Array, reflect.Slice:
372 // We can work with this. Normal case, fallthrough.
377 if v.Kind() == reflect.Slice && i >= v.Len() {
378 v.Set(reflect.Append(v, reflect.Zero(v.Type().Elem())))
382 ok, err := d.parseValue(v.Index(i))
390 _, ok := d.parseValueInterface()
398 if v.Kind() == reflect.Array {
399 z := reflect.Zero(v.Type().Elem())
400 for n := v.Len(); i < n; i++ {
408 if i == 0 && v.Kind() == reflect.Slice {
409 v.Set(reflect.MakeSlice(v.Type(), 0, 0))
414 func (d *Decoder) readOneValue() bool {
415 b, err := d.r.ReadByte()
429 // read until there is nothing to read
430 for d.readOneValue() {
432 // consume 'e' as well
437 d.buf.WriteString("e")
439 if b >= '0' && b <= '9' {
440 start := d.buf.Len() - 1
442 length, err := strconv.ParseInt(bytesAsString(d.buf.Bytes()[start:]), 10, 64)
443 checkForIntParseError(err, d.Offset-1)
445 d.buf.WriteString(":")
446 n, err := io.CopyN(&d.buf, d.r, length)
449 checkForUnexpectedEOF(err, d.Offset)
452 What: errors.New("unexpected I/O error: " + err.Error()),
458 d.raiseUnknownValueType(b, d.Offset-1)
465 func (d *Decoder) parseUnmarshaler(v reflect.Value) bool {
466 if !v.Type().Implements(unmarshalerType) {
467 if v.Addr().Type().Implements(unmarshalerType) {
474 if !d.readOneValue() {
477 m := v.Interface().(Unmarshaler)
478 err := m.UnmarshalBencode(d.buf.Bytes())
480 panic(&UnmarshalerError{v.Type(), err})
485 // Returns true if there was a value and it's now stored in 'v', otherwise
486 // there was an end symbol ("e") and no value was stored.
487 func (d *Decoder) parseValue(v reflect.Value) (bool, error) {
488 // we support one level of indirection at the moment
489 if v.Kind() == reflect.Ptr {
490 // if the pointer is nil, allocate a new element of the type it
493 v.Set(reflect.New(v.Type().Elem()))
498 if d.parseUnmarshaler(v) {
502 // common case: interface{}
503 if v.Kind() == reflect.Interface && v.NumMethod() == 0 {
504 iface, _ := d.parseValueInterface()
505 v.Set(reflect.ValueOf(iface))
509 b, err := d.r.ReadByte()
519 return true, d.parseDict(v)
521 return true, d.parseList(v)
526 if b >= '0' && b <= '9' {
529 // Write the first digit of the length to the buffer.
531 return true, d.parseString(v)
534 d.raiseUnknownValueType(b, d.Offset-1)
539 // An unknown bencode type character was encountered.
540 func (d *Decoder) raiseUnknownValueType(b byte, offset int64) {
543 What: fmt.Errorf("unknown value type %+q", b),
547 func (d *Decoder) parseValueInterface() (interface{}, bool) {
548 b, err := d.r.ReadByte()
558 return d.parseDictInterface(), true
560 return d.parseListInterface(), true
562 return d.parseIntInterface(), true
564 if b >= '0' && b <= '9' {
566 // append first digit of the length to the buffer
568 return d.parseStringInterface(), true
571 d.raiseUnknownValueType(b, d.Offset-1)
576 func (d *Decoder) parseIntInterface() (ret interface{}) {
577 start := d.Offset - 1
579 if d.buf.Len() == 0 {
582 What: errors.New("empty integer value"),
586 n, err := strconv.ParseInt(d.buf.String(), 10, 64)
587 if ne, ok := err.(*strconv.NumError); ok && ne.Err == strconv.ErrRange {
589 _, ok := i.SetString(d.buf.String(), 10)
593 What: errors.New("failed to parse integer"),
598 checkForIntParseError(err, start)
606 func (d *Decoder) parseStringInterface() interface{} {
607 start := d.Offset - 1
609 // read the string length first
611 length, err := strconv.ParseInt(d.buf.String(), 10, 64)
612 checkForIntParseError(err, start)
615 n, err := io.CopyN(&d.buf, d.r, length)
618 checkForUnexpectedEOF(err, d.Offset)
621 What: errors.New("unexpected I/O error: " + err.Error()),
630 func (d *Decoder) parseDictInterface() interface{} {
631 dict := make(map[string]interface{})
633 keyi, ok := d.parseValueInterface()
638 key, ok := keyi.(string)
642 What: errors.New("non-string key in a dict"),
646 valuei, ok := d.parseValueInterface()
656 func (d *Decoder) parseListInterface() interface{} {
657 var list []interface{}
659 valuei, ok := d.parseValueInterface()
664 list = append(list, valuei)
667 list = make([]interface{}, 0, 0)