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")
246 type structField struct {
247 r reflect.StructField
252 structFieldsMu sync.Mutex
253 structFields = map[reflect.Type]map[string]dictField{}
256 func parseStructFields(struct_ reflect.Type, each func(string, dictField)) {
257 for _i, n := 0, struct_.NumField(); _i < n; _i++ {
259 f := struct_.Field(i)
263 tagStr := f.Tag.Get("bencode")
267 tag := parseTag(tagStr)
272 each(key, dictField{f.Type, func(value reflect.Value) func(reflect.Value) {
273 return value.Field(i).Set
278 func saveStructFields(struct_ reflect.Type) {
279 m := make(map[string]dictField)
280 parseStructFields(struct_, func(key string, sf dictField) {
283 structFields[struct_] = m
286 func getStructFieldForKey(struct_ reflect.Type, key string) (f dictField) {
287 structFieldsMu.Lock()
288 if _, ok := structFields[struct_]; !ok {
289 saveStructFields(struct_)
291 f, ok := structFields[struct_][key]
292 structFieldsMu.Unlock()
294 var discard interface{}
296 Type: reflect.TypeOf(discard),
297 Get: func(reflect.Value) func(reflect.Value) { return func(reflect.Value) {} },
304 func (d *Decoder) parseDict(v reflect.Value) error {
305 // so, at this point 'd' byte was consumed, let's just read key/value
309 keyValue := reflect.ValueOf(&keyStr).Elem()
310 ok, err := d.parseValue(keyValue)
312 return fmt.Errorf("error parsing dict key: %s", err)
318 df := getDictField(v.Type(), keyStr)
320 // now we need to actually parse it
322 // Discard the value, there's nowhere to put it.
324 if_, ok = d.parseValueInterface()
326 return fmt.Errorf("error parsing value for key %q", keyStr)
329 return fmt.Errorf("missing value for key %q", keyStr)
333 setValue := reflect.New(df.Type).Elem()
334 //log.Printf("parsing into %v", setValue.Type())
335 ok, err = d.parseValue(setValue)
337 if _, ok := err.(*UnmarshalTypeError); !ok || !df.Tags.IgnoreUnmarshalTypeError() {
338 return fmt.Errorf("parsing value for key %q: %s", keyStr, err)
342 return fmt.Errorf("missing value for key %q", keyStr)
348 func (d *Decoder) parseList(v reflect.Value) error {
351 // If the list is a singleton of the expected type, use that value. See
352 // https://github.com/anacrolix/torrent/issues/297.
353 l := reflect.New(reflect.SliceOf(v.Type()))
354 if err := d.parseList(l.Elem()); err != nil {
357 if l.Elem().Len() != 1 {
358 return &UnmarshalTypeError{
363 v.Set(l.Elem().Index(0))
365 case reflect.Array, reflect.Slice:
366 // We can work with this. Normal case, fallthrough.
371 if v.Kind() == reflect.Slice && i >= v.Len() {
372 v.Set(reflect.Append(v, reflect.Zero(v.Type().Elem())))
376 ok, err := d.parseValue(v.Index(i))
384 _, ok := d.parseValueInterface()
392 if v.Kind() == reflect.Array {
393 z := reflect.Zero(v.Type().Elem())
394 for n := v.Len(); i < n; i++ {
402 if i == 0 && v.Kind() == reflect.Slice {
403 v.Set(reflect.MakeSlice(v.Type(), 0, 0))
408 func (d *Decoder) readOneValue() bool {
409 b, err := d.r.ReadByte()
423 // read until there is nothing to read
424 for d.readOneValue() {
426 // consume 'e' as well
431 d.buf.WriteString("e")
433 if b >= '0' && b <= '9' {
434 start := d.buf.Len() - 1
436 length, err := strconv.ParseInt(bytesAsString(d.buf.Bytes()[start:]), 10, 64)
437 checkForIntParseError(err, d.Offset-1)
439 d.buf.WriteString(":")
440 n, err := io.CopyN(&d.buf, d.r, length)
443 checkForUnexpectedEOF(err, d.Offset)
446 What: errors.New("unexpected I/O error: " + err.Error()),
452 d.raiseUnknownValueType(b, d.Offset-1)
459 func (d *Decoder) parseUnmarshaler(v reflect.Value) bool {
460 if !v.Type().Implements(unmarshalerType) {
461 if v.Addr().Type().Implements(unmarshalerType) {
468 if !d.readOneValue() {
471 m := v.Interface().(Unmarshaler)
472 err := m.UnmarshalBencode(d.buf.Bytes())
474 panic(&UnmarshalerError{v.Type(), err})
479 // Returns true if there was a value and it's now stored in 'v', otherwise
480 // there was an end symbol ("e") and no value was stored.
481 func (d *Decoder) parseValue(v reflect.Value) (bool, error) {
482 // we support one level of indirection at the moment
483 if v.Kind() == reflect.Ptr {
484 // if the pointer is nil, allocate a new element of the type it
487 v.Set(reflect.New(v.Type().Elem()))
492 if d.parseUnmarshaler(v) {
496 // common case: interface{}
497 if v.Kind() == reflect.Interface && v.NumMethod() == 0 {
498 iface, _ := d.parseValueInterface()
499 v.Set(reflect.ValueOf(iface))
503 b, err := d.r.ReadByte()
513 return true, d.parseDict(v)
515 return true, d.parseList(v)
520 if b >= '0' && b <= '9' {
523 // Write the first digit of the length to the buffer.
525 return true, d.parseString(v)
528 d.raiseUnknownValueType(b, d.Offset-1)
533 // An unknown bencode type character was encountered.
534 func (d *Decoder) raiseUnknownValueType(b byte, offset int64) {
537 What: fmt.Errorf("unknown value type %+q", b),
541 func (d *Decoder) parseValueInterface() (interface{}, bool) {
542 b, err := d.r.ReadByte()
552 return d.parseDictInterface(), true
554 return d.parseListInterface(), true
556 return d.parseIntInterface(), true
558 if b >= '0' && b <= '9' {
560 // append first digit of the length to the buffer
562 return d.parseStringInterface(), true
565 d.raiseUnknownValueType(b, d.Offset-1)
570 func (d *Decoder) parseIntInterface() (ret interface{}) {
571 start := d.Offset - 1
573 if d.buf.Len() == 0 {
576 What: errors.New("empty integer value"),
580 n, err := strconv.ParseInt(d.buf.String(), 10, 64)
581 if ne, ok := err.(*strconv.NumError); ok && ne.Err == strconv.ErrRange {
583 _, ok := i.SetString(d.buf.String(), 10)
587 What: errors.New("failed to parse integer"),
592 checkForIntParseError(err, start)
600 func (d *Decoder) parseStringInterface() interface{} {
601 start := d.Offset - 1
603 // read the string length first
605 length, err := strconv.ParseInt(d.buf.String(), 10, 64)
606 checkForIntParseError(err, start)
609 n, err := io.CopyN(&d.buf, d.r, length)
612 checkForUnexpectedEOF(err, d.Offset)
615 What: errors.New("unexpected I/O error: " + err.Error()),
624 func (d *Decoder) parseDictInterface() interface{} {
625 dict := make(map[string]interface{})
627 keyi, ok := d.parseValueInterface()
632 key, ok := keyi.(string)
636 What: errors.New("non-string key in a dict"),
640 valuei, ok := d.parseValueInterface()
650 func (d *Decoder) parseListInterface() interface{} {
651 var list []interface{}
653 valuei, ok := d.parseValueInterface()
658 list = append(list, valuei)
661 list = make([]interface{}, 0, 0)