9 "github.com/anacrolix/missinggo/expect"
12 //----------------------------------------------------------------------------
14 //----------------------------------------------------------------------------
16 // In case if marshaler cannot encode a type, it will return this error. Typical
17 // example of such type is float32/float64 which has no bencode representation.
18 type MarshalTypeError struct {
22 func (e *MarshalTypeError) Error() string {
23 return "bencode: unsupported type: " + e.Type.String()
26 // Unmarshal argument must be a non-nil value of some pointer type.
27 type UnmarshalInvalidArgError struct {
31 func (e *UnmarshalInvalidArgError) Error() string {
33 return "bencode: Unmarshal(nil)"
36 if e.Type.Kind() != reflect.Ptr {
37 return "bencode: Unmarshal(non-pointer " + e.Type.String() + ")"
39 return "bencode: Unmarshal(nil " + e.Type.String() + ")"
42 // Unmarshaler spotted a value that was not appropriate for a given Go value.
43 type UnmarshalTypeError struct {
44 BencodeTypeName string
45 UnmarshalTargetType reflect.Type
48 // This could probably be a value type, but we may already have users assuming
49 // that it's passed by pointer.
50 func (e *UnmarshalTypeError) Error() string {
52 "can't unmarshal a bencode %v into a %v",
54 e.UnmarshalTargetType,
58 // Unmarshaler tried to write to an unexported (therefore unwritable) field.
59 type UnmarshalFieldError struct {
62 Field reflect.StructField
65 func (e *UnmarshalFieldError) Error() string {
66 return "bencode: key \"" + e.Key + "\" led to an unexported field \"" +
67 e.Field.Name + "\" in type: " + e.Type.String()
70 // Malformed bencode input, unmarshaler failed to parse it.
71 type SyntaxError struct {
72 Offset int64 // location of the error
73 What error // error description
76 func (e *SyntaxError) Error() string {
77 return fmt.Sprintf("bencode: syntax error (offset: %d): %s", e.Offset, e.What)
80 // A non-nil error was returned after calling MarshalBencode on a type which
81 // implements the Marshaler interface.
82 type MarshalerError struct {
87 func (e *MarshalerError) Error() string {
88 return "bencode: error calling MarshalBencode for type " + e.Type.String() + ": " + e.Err.Error()
91 // A non-nil error was returned after calling UnmarshalBencode on a type which
92 // implements the Unmarshaler interface.
93 type UnmarshalerError struct {
98 func (e *UnmarshalerError) Error() string {
99 return "bencode: error calling UnmarshalBencode for type " + e.Type.String() + ": " + e.Err.Error()
102 //----------------------------------------------------------------------------
104 //----------------------------------------------------------------------------
106 // Any type which implements this interface, will be marshaled using the
108 type Marshaler interface {
109 MarshalBencode() ([]byte, error)
112 // Any type which implements this interface, will be unmarshaled using the
114 type Unmarshaler interface {
115 UnmarshalBencode([]byte) error
118 // Marshal the value 'v' to the bencode form, return the result as []byte and
120 func Marshal(v interface{}) ([]byte, error) {
122 e := Encoder{w: &buf}
127 return buf.Bytes(), nil
130 func MustMarshal(v interface{}) []byte {
136 // Unmarshal the bencode value in the 'data' to a value pointed by the 'v' pointer, return a non-nil
137 // error if any. If there are trailing bytes, this results in ErrUnusedTrailingBytes, but the value
138 // will be valid. It's probably more consistent to use Decoder.Decode if you want to rely on this
139 // behaviour (inspired by Rust's serde here).
140 func Unmarshal(data []byte, v interface{}) (err error) {
141 buf := bytes.NewReader(data)
144 if err == nil && buf.Len() != 0 {
145 err = ErrUnusedTrailingBytes{buf.Len()}
150 type ErrUnusedTrailingBytes struct {
154 func (me ErrUnusedTrailingBytes) Error() string {
155 return fmt.Sprintf("%d unused trailing bytes", me.NumUnusedBytes)
158 func NewDecoder(r io.Reader) *Decoder {
159 return &Decoder{r: &scanner{r: r}}
162 func NewEncoder(w io.Writer) *Encoder {
163 return &Encoder{w: w}