source: code/trunk/conn.go@ 293

package soju

import (
        "fmt"
        "net"
        "sync"
        "time"

        "gopkg.in/irc.v3"
)

func setKeepAlive(c net.Conn) error {
        tcpConn, ok := c.(*net.TCPConn)
        if !ok {
                return fmt.Errorf("cannot enable keep-alive on a non-TCP connection")
        }
        if err := tcpConn.SetKeepAlive(true); err != nil {
                return err
        }
        return tcpConn.SetKeepAlivePeriod(keepAlivePeriod)
}

type conn struct {
        net    net.Conn
        irc    *irc.Conn
        srv    *Server
        logger Logger

        lock     sync.Mutex
        outgoing chan<- *irc.Message
        closed   bool
}

func newConn(srv *Server, netConn net.Conn, logger Logger) *conn {
        setKeepAlive(netConn)

        outgoing := make(chan *irc.Message, 64)
        c := &conn{
                net:      netConn,
                irc:      irc.NewConn(netConn),
                srv:      srv,
                outgoing: outgoing,
                logger:   logger,
        }

        go func() {
                for msg := range outgoing {
                        if c.srv.Debug {
                                c.logger.Printf("sent: %v", msg)
                        }
                        c.net.SetWriteDeadline(time.Now().Add(writeTimeout))
                        if err := c.irc.WriteMessage(msg); err != nil {
                                c.logger.Printf("failed to write message: %v", err)
                                break
                        }
                }
                if err := c.net.Close(); err != nil {
                        c.logger.Printf("failed to close connection: %v", err)
                } else {
                        c.logger.Printf("connection closed")
                }
                // Drain the outgoing channel to prevent SendMessage from blocking
                for range outgoing {
                        // This space is intentionally left blank
                }
        }()

        c.logger.Printf("new connection")
        return c
}

func (c *conn) isClosed() bool {
        c.lock.Lock()
        defer c.lock.Unlock()
        return c.closed
}

// Close closes the connection. It is safe to call from any goroutine.
func (c *conn) Close() error {
        c.lock.Lock()
        defer c.lock.Unlock()

        if c.closed {
                return fmt.Errorf("connection already closed")
        }

        c.closed = true
        close(c.outgoing)
        return nil
}

func (c *conn) ReadMessage() (*irc.Message, error) {
        msg, err := c.irc.ReadMessage()
        if err != nil {
                return nil, err
        }

        if c.srv.Debug {
                c.logger.Printf("received: %v", msg)
        }

        return msg, nil
}

// SendMessage queues a new outgoing message. It is safe to call from any
// goroutine.
//
// If the connection is closed before the message is sent, SendMessage silently
// drops the message.
func (c *conn) SendMessage(msg *irc.Message) {
        c.lock.Lock()
        defer c.lock.Unlock()

        if c.closed {
                return
        }
        c.outgoing <- msg
}