// Copyright 2014 Vic Demuzere
//
// Use of this source code is governed by the MIT license.
package irc
import (
"bufio"
"io"
"net"
"sync"
)
// Messages are delimited with CR and LF line endings,
// we're using the last one to split the stream. Both are removed
// during message parsing.
const delim byte = '\n'
var endline = []byte("\r\n")
// A Conn represents an IRC network protocol connection.
// It consists of an Encoder and Decoder to manage I/O.
type Conn struct {
Encoder
Decoder
conn io.ReadWriteCloser
}
// NewConn returns a new Conn using rwc for I/O.
func NewConn(rwc io.ReadWriteCloser) *Conn {
return &Conn{
Encoder: Encoder{
writer: rwc,
},
Decoder: Decoder{
reader: bufio.NewReader(rwc),
},
conn: rwc,
}
}
// Dial connects to the given address using net.Dial and
// then returns a new Conn for the connection.
func Dial(addr string) (*Conn, error) {
c, err := net.Dial("tcp", addr)
if err != nil {
return nil, err
}
return NewConn(c), nil
}
// Close closes the underlying ReadWriteCloser.
func (c *Conn) Close() error {
return c.conn.Close()
}
// A Decoder reads Message objects from an input stream.
type Decoder struct {
reader *bufio.Reader
line string
mu sync.Mutex
}
// NewDecoder returns a new Decoder that reads from r.
func NewDecoder(r io.Reader) *Decoder {
return &Decoder{
reader: bufio.NewReader(r),
}
}
// Decode attempts to read a single Message from the stream.
//
// Returns a non-nil error if the read failed.
func (dec *Decoder) Decode() (m *Message, err error) {
dec.mu.Lock()
dec.line, err = dec.reader.ReadString(delim)
dec.mu.Unlock()
if err != nil {
return nil, err
}
return ParseMessage(dec.line), nil
}
// An Encoder writes Message objects to an output stream.
type Encoder struct {
writer io.Writer
mu sync.Mutex
}
// NewEncoder returns a new Encoder that writes to w.
func NewEncoder(w io.Writer) *Encoder {
return &Encoder{
writer: w,
}
}
// Encode writes the IRC encoding of m to the stream.
//
// This method may be used from multiple goroutines.
//
// Returns an non-nil error if the write to the underlying stream stopped early.
func (enc *Encoder) Encode(m *Message) (err error) {
_, err = enc.Write(m.Bytes())
return
}
// Write writes len(p) bytes from p followed by CR+LF.
//
// This method can be used simultaneously from multiple goroutines,
// it guarantees to serialize access. However, writing a single IRC message
// using multiple Write calls will cause corruption.
func (enc *Encoder) Write(p []byte) (n int, err error) {
enc.mu.Lock()
n, err = enc.writer.Write(p)
if err != nil {
enc.mu.Unlock()
return
}
_, err = enc.writer.Write(endline)
enc.mu.Unlock()
return
}