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)
257 if t.Kind() == reflect.Ptr {
260 parseStructFields(t, func(key string, df dictField) {
262 df.Get = func(value reflect.Value) func(reflect.Value) {
263 anonPtr := value.Field(i)
264 if anonPtr.Kind() == reflect.Ptr && anonPtr.IsNil() {
265 anonPtr.Set(reflect.New(f.Type.Elem()))
266 anonPtr = anonPtr.Elem()
268 return innerGet(anonPtr)
274 tagStr := f.Tag.Get("bencode")
278 tag := parseTag(tagStr)
283 each(key, dictField{f.Type, func(value reflect.Value) func(reflect.Value) {
284 return value.Field(i).Set
289 func saveStructFields(struct_ reflect.Type) {
290 m := make(map[string]dictField)
291 parseStructFields(struct_, func(key string, sf dictField) {
294 structFields[struct_] = m
297 func getStructFieldForKey(struct_ reflect.Type, key string) (f dictField) {
298 structFieldsMu.Lock()
299 if _, ok := structFields[struct_]; !ok {
300 saveStructFields(struct_)
302 f, ok := structFields[struct_][key]
303 structFieldsMu.Unlock()
305 var discard interface{}
307 Type: reflect.TypeOf(discard),
308 Get: func(reflect.Value) func(reflect.Value) { return func(reflect.Value) {} },
315 func (d *Decoder) parseDict(v reflect.Value) error {
316 // so, at this point 'd' byte was consumed, let's just read key/value
320 keyValue := reflect.ValueOf(&keyStr).Elem()
321 ok, err := d.parseValue(keyValue)
323 return fmt.Errorf("error parsing dict key: %s", err)
329 df := getDictField(v.Type(), keyStr)
331 // now we need to actually parse it
333 // Discard the value, there's nowhere to put it.
335 if_, ok = d.parseValueInterface()
337 return fmt.Errorf("error parsing value for key %q", keyStr)
340 return fmt.Errorf("missing value for key %q", keyStr)
344 setValue := reflect.New(df.Type).Elem()
345 //log.Printf("parsing into %v", setValue.Type())
346 ok, err = d.parseValue(setValue)
348 if _, ok := err.(*UnmarshalTypeError); !ok || !df.Tags.IgnoreUnmarshalTypeError() {
349 return fmt.Errorf("parsing value for key %q: %s", keyStr, err)
353 return fmt.Errorf("missing value for key %q", keyStr)
359 func (d *Decoder) parseList(v reflect.Value) error {
362 // If the list is a singleton of the expected type, use that value. See
363 // https://github.com/anacrolix/torrent/issues/297.
364 l := reflect.New(reflect.SliceOf(v.Type()))
365 if err := d.parseList(l.Elem()); err != nil {
368 if l.Elem().Len() != 1 {
369 return &UnmarshalTypeError{
374 v.Set(l.Elem().Index(0))
376 case reflect.Array, reflect.Slice:
377 // We can work with this. Normal case, fallthrough.
382 if v.Kind() == reflect.Slice && i >= v.Len() {
383 v.Set(reflect.Append(v, reflect.Zero(v.Type().Elem())))
387 ok, err := d.parseValue(v.Index(i))
395 _, ok := d.parseValueInterface()
403 if v.Kind() == reflect.Array {
404 z := reflect.Zero(v.Type().Elem())
405 for n := v.Len(); i < n; i++ {
413 if i == 0 && v.Kind() == reflect.Slice {
414 v.Set(reflect.MakeSlice(v.Type(), 0, 0))
419 func (d *Decoder) readOneValue() bool {
420 b, err := d.r.ReadByte()
434 // read until there is nothing to read
435 for d.readOneValue() {
437 // consume 'e' as well
442 d.buf.WriteString("e")
444 if b >= '0' && b <= '9' {
445 start := d.buf.Len() - 1
447 length, err := strconv.ParseInt(bytesAsString(d.buf.Bytes()[start:]), 10, 64)
448 checkForIntParseError(err, d.Offset-1)
450 d.buf.WriteString(":")
451 n, err := io.CopyN(&d.buf, d.r, length)
454 checkForUnexpectedEOF(err, d.Offset)
457 What: errors.New("unexpected I/O error: " + err.Error()),
463 d.raiseUnknownValueType(b, d.Offset-1)
470 func (d *Decoder) parseUnmarshaler(v reflect.Value) bool {
471 if !v.Type().Implements(unmarshalerType) {
472 if v.Addr().Type().Implements(unmarshalerType) {
479 if !d.readOneValue() {
482 m := v.Interface().(Unmarshaler)
483 err := m.UnmarshalBencode(d.buf.Bytes())
485 panic(&UnmarshalerError{v.Type(), err})
490 // Returns true if there was a value and it's now stored in 'v', otherwise
491 // there was an end symbol ("e") and no value was stored.
492 func (d *Decoder) parseValue(v reflect.Value) (bool, error) {
493 // we support one level of indirection at the moment
494 if v.Kind() == reflect.Ptr {
495 // if the pointer is nil, allocate a new element of the type it
498 v.Set(reflect.New(v.Type().Elem()))
503 if d.parseUnmarshaler(v) {
507 // common case: interface{}
508 if v.Kind() == reflect.Interface && v.NumMethod() == 0 {
509 iface, _ := d.parseValueInterface()
510 v.Set(reflect.ValueOf(iface))
514 b, err := d.r.ReadByte()
524 return true, d.parseDict(v)
526 return true, d.parseList(v)
531 if b >= '0' && b <= '9' {
534 // Write the first digit of the length to the buffer.
536 return true, d.parseString(v)
539 d.raiseUnknownValueType(b, d.Offset-1)
544 // An unknown bencode type character was encountered.
545 func (d *Decoder) raiseUnknownValueType(b byte, offset int64) {
548 What: fmt.Errorf("unknown value type %+q", b),
552 func (d *Decoder) parseValueInterface() (interface{}, bool) {
553 b, err := d.r.ReadByte()
563 return d.parseDictInterface(), true
565 return d.parseListInterface(), true
567 return d.parseIntInterface(), true
569 if b >= '0' && b <= '9' {
571 // append first digit of the length to the buffer
573 return d.parseStringInterface(), true
576 d.raiseUnknownValueType(b, d.Offset-1)
581 func (d *Decoder) parseIntInterface() (ret interface{}) {
582 start := d.Offset - 1
584 if d.buf.Len() == 0 {
587 What: errors.New("empty integer value"),
591 n, err := strconv.ParseInt(d.buf.String(), 10, 64)
592 if ne, ok := err.(*strconv.NumError); ok && ne.Err == strconv.ErrRange {
594 _, ok := i.SetString(d.buf.String(), 10)
598 What: errors.New("failed to parse integer"),
603 checkForIntParseError(err, start)
611 func (d *Decoder) parseStringInterface() interface{} {
612 start := d.Offset - 1
614 // read the string length first
616 length, err := strconv.ParseInt(d.buf.String(), 10, 64)
617 checkForIntParseError(err, start)
620 n, err := io.CopyN(&d.buf, d.r, length)
623 checkForUnexpectedEOF(err, d.Offset)
626 What: errors.New("unexpected I/O error: " + err.Error()),
635 func (d *Decoder) parseDictInterface() interface{} {
636 dict := make(map[string]interface{})
638 keyi, ok := d.parseValueInterface()
643 key, ok := keyi.(string)
647 What: errors.New("non-string key in a dict"),
651 valuei, ok := d.parseValueInterface()
661 func (d *Decoder) parseListInterface() interface{} {
662 var list []interface{}
664 valuei, ok := d.parseValueInterface()
669 list = append(list, valuei)
672 list = make([]interface{}, 0, 0)