status-go/vendor/github.com/pion/datachannel/message.go

74 lines
1.6 KiB
Go

package datachannel
import (
"fmt"
)
// message is a parsed DataChannel message
type message interface {
Marshal() ([]byte, error)
Unmarshal([]byte) error
}
// messageType is the first byte in a DataChannel message that specifies type
type messageType byte
// DataChannel Message Types
const (
dataChannelAck messageType = 0x02
dataChannelOpen messageType = 0x03
)
func (t messageType) String() string {
switch t {
case dataChannelAck:
return "DataChannelAck"
case dataChannelOpen:
return "DataChannelOpen"
default:
return fmt.Sprintf("Unknown MessageType: %d", t)
}
}
// parse accepts raw input and returns a DataChannel message
func parse(raw []byte) (message, error) {
if len(raw) == 0 {
return nil, ErrDataChannelMessageTooShort
}
var msg message
switch messageType(raw[0]) {
case dataChannelOpen:
msg = &channelOpen{}
case dataChannelAck:
msg = &channelAck{}
default:
return nil, fmt.Errorf("%w %v", ErrInvalidMessageType, messageType(raw[0]))
}
if err := msg.Unmarshal(raw); err != nil {
return nil, err
}
return msg, nil
}
// parseExpectDataChannelOpen parses a DataChannelOpen message
// or throws an error
func parseExpectDataChannelOpen(raw []byte) (*channelOpen, error) {
if len(raw) == 0 {
return nil, ErrDataChannelMessageTooShort
}
if actualTyp := messageType(raw[0]); actualTyp != dataChannelOpen {
return nil, fmt.Errorf("%w expected(%s) actual(%s)", ErrUnexpectedDataChannelType, actualTyp, dataChannelOpen)
}
msg := &channelOpen{}
if err := msg.Unmarshal(raw); err != nil {
return nil, err
}
return msg, nil
}