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ergo/irc/ircconn.go
2021-05-26 15:55:24 -04:00

147 lines
3.5 KiB
Go

// Copyright (c) 2020 Shivaram Lingamneni
// released under the MIT license
package irc
import (
"bytes"
"net"
"unicode/utf8"
"github.com/gorilla/websocket"
"github.com/goshuirc/irc-go/ircmsg"
"github.com/goshuirc/irc-go/ircreader"
"github.com/ergochat/ergo/irc/utils"
)
const (
initialBufferSize = 1024
)
var (
crlf = []byte{'\r', '\n'}
)
// maximum total length, in bytes, of a single IRC message:
func maxReadQBytes() int {
return ircmsg.MaxlenTagsFromClient + MaxLineLen + 1024
}
// IRCConn abstracts away the distinction between a regular
// net.Conn (which includes both raw TCP and TLS) and a websocket.
// it doesn't expose the net.Conn, io.Reader, or io.Writer interfaces
// because websockets are message-oriented, not stream-oriented, and
// therefore this abstraction is message-oriented as well.
type IRCConn interface {
UnderlyingConn() *utils.WrappedConn
// these take an IRC line or lines, correctly terminated with CRLF:
WriteLine([]byte) error
WriteLines([][]byte) error
// this returns an IRC line, possibly terminated with CRLF, LF, or nothing:
ReadLine() (line []byte, err error)
Close() error
}
// IRCStreamConn is an IRCConn over a regular stream connection.
type IRCStreamConn struct {
conn *utils.WrappedConn
reader ircreader.Reader
}
func NewIRCStreamConn(conn *utils.WrappedConn) *IRCStreamConn {
var c IRCStreamConn
c.conn = conn
c.reader.Initialize(conn.Conn, initialBufferSize, maxReadQBytes())
return &c
}
func (cc *IRCStreamConn) UnderlyingConn() *utils.WrappedConn {
return cc.conn
}
func (cc *IRCStreamConn) WriteLine(buf []byte) (err error) {
_, err = cc.conn.Write(buf)
return
}
func (cc *IRCStreamConn) WriteLines(buffers [][]byte) (err error) {
// on Linux, with a plaintext TCP or Unix domain socket,
// the Go runtime will optimize this into a single writev(2) call:
_, err = (*net.Buffers)(&buffers).WriteTo(cc.conn)
return
}
func (cc *IRCStreamConn) ReadLine() ([]byte, error) {
line, err := cc.reader.ReadLine()
if err != nil {
return nil, err
} else if globalUtf8EnforcementSetting && !utf8.Valid(line) {
return line, errInvalidUtf8
} else {
return line, nil
}
}
func (cc *IRCStreamConn) Close() (err error) {
return cc.conn.Close()
}
// IRCWSConn is an IRCConn over a websocket.
type IRCWSConn struct {
conn *websocket.Conn
binary bool
}
func NewIRCWSConn(conn *websocket.Conn) IRCWSConn {
binary := conn.Subprotocol() == "binary.ircv3.net"
return IRCWSConn{conn: conn, binary: binary}
}
func (wc IRCWSConn) UnderlyingConn() *utils.WrappedConn {
// just assume that the type is OK
wConn, _ := wc.conn.UnderlyingConn().(*utils.WrappedConn)
return wConn
}
func (wc IRCWSConn) WriteLine(buf []byte) (err error) {
buf = bytes.TrimSuffix(buf, crlf)
// #1483: if we have websockets at all, then we're enforcing utf8
messageType := websocket.TextMessage
if wc.binary {
messageType = websocket.BinaryMessage
}
return wc.conn.WriteMessage(messageType, buf)
}
func (wc IRCWSConn) WriteLines(buffers [][]byte) (err error) {
for _, buf := range buffers {
err = wc.WriteLine(buf)
if err != nil {
return
}
}
return
}
func (wc IRCWSConn) ReadLine() (line []byte, err error) {
messageType, line, err := wc.conn.ReadMessage()
if err == nil {
if messageType == websocket.BinaryMessage && !utf8.Valid(line) {
return line, errInvalidUtf8
}
return line, nil
} else if err == websocket.ErrReadLimit {
return line, ircreader.ErrReadQ
} else {
return line, err
}
}
func (wc IRCWSConn) Close() (err error) {
return wc.conn.Close()
}