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()
217 dict.Set(reflect.MakeMap(dict.Type()))
219 // Assigns the value into the map.
220 dict.SetMapIndex(reflect.ValueOf(key).Convert(dict.Type().Key()), value)
224 sf, ok := getStructFieldForKey(dict.Type(), key)
228 if sf.PkgPath != "" {
229 panic(&UnmarshalFieldError{
236 Value: dict.FieldByIndex(sf.Index),
239 IgnoreUnmarshalTypeError: getTag(sf.Tag).IgnoreUnmarshalTypeError(),
247 structFieldsMu sync.Mutex
248 structFields = map[reflect.Type]map[string]reflect.StructField{}
251 func parseStructFields(struct_ reflect.Type, each func(string, reflect.StructField)) {
252 for i, n := 0, struct_.NumField(); i < n; i++ {
253 f := struct_.Field(i)
254 tag := f.Tag.Get("bencode")
261 if key := parseTag(tag).Key(); key != "" {
269 func saveStructFields(struct_ reflect.Type) {
270 m := make(map[string]reflect.StructField)
271 parseStructFields(struct_, func(key string, sf reflect.StructField) {
274 structFields[struct_] = m
277 func getStructFieldForKey(struct_ reflect.Type, key string) (f reflect.StructField, ok bool) {
278 structFieldsMu.Lock()
279 if _, ok := structFields[struct_]; !ok {
280 saveStructFields(struct_)
282 f, ok = structFields[struct_][key]
283 structFieldsMu.Unlock()
287 func (d *Decoder) parseDict(v reflect.Value) error {
288 // so, at this point 'd' byte was consumed, let's just read key/value
292 keyValue := reflect.ValueOf(&keyStr).Elem()
293 ok, err := d.parseValue(keyValue)
295 return fmt.Errorf("error parsing dict key: %s", err)
301 df := getDictField(v, keyStr)
303 // now we need to actually parse it
305 // log.Printf("parsing ok struct field for key %q", keyStr)
306 ok, err = d.parseValue(df.Value)
308 // Discard the value, there's nowhere to put it.
310 if_, ok = d.parseValueInterface()
312 err = fmt.Errorf("error parsing value for key %q", keyStr)
316 if _, ok := err.(*UnmarshalTypeError); !ok || !df.IgnoreUnmarshalTypeError {
317 return fmt.Errorf("parsing value for key %q: %s", keyStr, err)
321 return fmt.Errorf("missing value for key %q", keyStr)
329 func (d *Decoder) parseList(v reflect.Value) error {
331 case reflect.Array, reflect.Slice:
333 panic(&UnmarshalTypeError{
341 if v.Kind() == reflect.Slice && i >= v.Len() {
342 v.Set(reflect.Append(v, reflect.Zero(v.Type().Elem())))
346 ok, err := d.parseValue(v.Index(i))
354 _, ok := d.parseValueInterface()
362 if v.Kind() == reflect.Array {
363 z := reflect.Zero(v.Type().Elem())
364 for n := v.Len(); i < n; i++ {
372 if i == 0 && v.Kind() == reflect.Slice {
373 v.Set(reflect.MakeSlice(v.Type(), 0, 0))
378 func (d *Decoder) readOneValue() bool {
379 b, err := d.r.ReadByte()
393 // read until there is nothing to read
394 for d.readOneValue() {
396 // consume 'e' as well
401 d.buf.WriteString("e")
403 if b >= '0' && b <= '9' {
404 start := d.buf.Len() - 1
406 s := reflect.StringHeader{
407 uintptr(unsafe.Pointer(&d.buf.Bytes()[start])),
410 length, err := strconv.ParseInt(*(*string)(unsafe.Pointer(&s)), 10, 64)
411 checkForIntParseError(err, d.Offset-1)
413 d.buf.WriteString(":")
414 n, err := io.CopyN(&d.buf, d.r, length)
417 checkForUnexpectedEOF(err, d.Offset)
420 What: errors.New("unexpected I/O error: " + err.Error()),
426 d.raiseUnknownValueType(b, d.Offset-1)
433 func (d *Decoder) parseUnmarshaler(v reflect.Value) bool {
434 m, ok := v.Interface().(Unmarshaler)
436 // T doesn't work, try *T
437 if v.Kind() != reflect.Ptr && v.CanAddr() {
438 m, ok = v.Addr().Interface().(Unmarshaler)
444 if ok && (v.Kind() != reflect.Ptr || !v.IsNil()) {
445 if d.readOneValue() {
446 err := m.UnmarshalBencode(d.buf.Bytes())
449 panic(&UnmarshalerError{v.Type(), err})
459 // Returns true if there was a value and it's now stored in 'v', otherwise
460 // there was an end symbol ("e") and no value was stored.
461 func (d *Decoder) parseValue(v reflect.Value) (bool, error) {
462 // we support one level of indirection at the moment
463 if v.Kind() == reflect.Ptr {
464 // if the pointer is nil, allocate a new element of the type it
467 v.Set(reflect.New(v.Type().Elem()))
472 if d.parseUnmarshaler(v) {
476 // common case: interface{}
477 if v.Kind() == reflect.Interface && v.NumMethod() == 0 {
478 iface, _ := d.parseValueInterface()
479 v.Set(reflect.ValueOf(iface))
483 b, err := d.r.ReadByte()
493 return true, d.parseDict(v)
495 return true, d.parseList(v)
500 if b >= '0' && b <= '9' {
503 // Write the first digit of the length to the buffer.
505 return true, d.parseString(v)
508 d.raiseUnknownValueType(b, d.Offset-1)
513 // An unknown bencode type character was encountered.
514 func (d *Decoder) raiseUnknownValueType(b byte, offset int64) {
517 What: fmt.Errorf("unknown value type %+q", b),
521 func (d *Decoder) parseValueInterface() (interface{}, bool) {
522 b, err := d.r.ReadByte()
532 return d.parseDictInterface(), true
534 return d.parseListInterface(), true
536 return d.parseIntInterface(), true
538 if b >= '0' && b <= '9' {
540 // append first digit of the length to the buffer
542 return d.parseStringInterface(), true
545 d.raiseUnknownValueType(b, d.Offset-1)
550 func (d *Decoder) parseIntInterface() (ret interface{}) {
551 start := d.Offset - 1
553 if d.buf.Len() == 0 {
556 What: errors.New("empty integer value"),
560 n, err := strconv.ParseInt(d.buf.String(), 10, 64)
561 if ne, ok := err.(*strconv.NumError); ok && ne.Err == strconv.ErrRange {
563 _, ok := i.SetString(d.buf.String(), 10)
567 What: errors.New("failed to parse integer"),
572 checkForIntParseError(err, start)
580 func (d *Decoder) parseStringInterface() interface{} {
581 start := d.Offset - 1
583 // read the string length first
585 length, err := strconv.ParseInt(d.buf.String(), 10, 64)
586 checkForIntParseError(err, start)
589 n, err := io.CopyN(&d.buf, d.r, length)
592 checkForUnexpectedEOF(err, d.Offset)
595 What: errors.New("unexpected I/O error: " + err.Error()),
604 func (d *Decoder) parseDictInterface() interface{} {
605 dict := make(map[string]interface{})
607 keyi, ok := d.parseValueInterface()
612 key, ok := keyi.(string)
616 What: errors.New("non-string key in a dict"),
620 valuei, ok := d.parseValueInterface()
630 func (d *Decoder) parseListInterface() interface{} {
631 var list []interface{}
633 valuei, ok := d.parseValueInterface()
638 list = append(list, valuei)
641 list = make([]interface{}, 0, 0)