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package protocol
import (
"bytes"
"fmt"
"io"
)
func (c *Client) Receive() (Message, error) {
var cmd [3]byte
_, err := io.ReadFull(c.rx, cmd[:])
if err != nil {
return nil, err
}
typ := Command(cmd[:])
switch typ {
case CmdMsg:
var length uint64
err = c.read(&length)
if err != nil {
return nil, err
}
data := make([]byte, length)
_, err = io.ReadFull(c.rx, data)
if err != nil {
return nil, err
}
return commandMsg{
data: data,
}, nil
case CmdNop:
fallthrough
case CmdBye:
fallthrough
case CmdNil:
return trivialCommand(typ), nil
default:
return nil, fmt.Errorf("unknown command from server: %v", string(cmd[:]))
}
}
type Message interface {
Command() Command
// Consume calls messageConsumer is this message contains a data message to the upper level.
Consume(messageConsumer func(reader io.Reader, length int64))
}
type trivialCommand Command
func (t trivialCommand) Consume(func(reader io.Reader, length int64)) {}
func (t trivialCommand) Command() Command {
return Command(t)
}
type commandMsg struct {
data []byte
}
func (c commandMsg) Consume(messageConsumer func(reader io.Reader, length int64)) {
messageConsumer(bytes.NewReader(c.data), int64(len(c.data)))
}
func (c commandMsg) Command() Command {
return CmdMsg
}
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