source: code/trunk/vendor/gopkg.in/irc.v3/conn.go@ 822

package irc

import (
        "bufio"
        "fmt"
        "io"
)

// Conn represents a simple IRC client. It embeds an irc.Reader and an
// irc.Writer.
type Conn struct {
        *Reader
        *Writer
}

// NewConn creates a new Conn
func NewConn(rw io.ReadWriter) *Conn {
        return &Conn{
                NewReader(rw),
                NewWriter(rw),
        }
}

// Writer is the outgoing side of a connection.
type Writer struct {
        // DebugCallback is called for each outgoing message. The name of this may
        // not be stable.
        DebugCallback func(line string)

        // Internal fields
        writer        io.Writer
        writeCallback func(w *Writer, line string) error
}

func defaultWriteCallback(w *Writer, line string) error {
        _, err := w.writer.Write([]byte(line + "\r\n"))
        return err
}

// NewWriter creates an irc.Writer from an io.Writer.
func NewWriter(w io.Writer) *Writer {
        return &Writer{nil, w, defaultWriteCallback}
}

// Write is a simple function which will write the given line to the
// underlying connection.
func (w *Writer) Write(line string) error {
        if w.DebugCallback != nil {
                w.DebugCallback(line)
        }

        return w.writeCallback(w, line)
}

// Writef is a wrapper around the connection's Write method and
// fmt.Sprintf. Simply use it to send a message as you would normally
// use fmt.Printf.
func (w *Writer) Writef(format string, args ...interface{}) error {
        return w.Write(fmt.Sprintf(format, args...))
}

// WriteMessage writes the given message to the stream
func (w *Writer) WriteMessage(m *Message) error {
        return w.Write(m.String())
}

// Reader is the incoming side of a connection. The data will be
// buffered, so do not re-use the io.Reader used to create the
// irc.Reader.
type Reader struct {
        // DebugCallback is called for each incoming message. The name of this may
        // not be stable.
        DebugCallback func(string)

        // Internal fields
        reader *bufio.Reader
}

// NewReader creates an irc.Reader from an io.Reader. Note that once a reader is
// passed into this function, you should no longer use it as it is being used
// inside a bufio.Reader so you cannot rely on only the amount of data for a
// Message being read when you call ReadMessage.
func NewReader(r io.Reader) *Reader {
        return &Reader{
                nil,
                bufio.NewReader(r),
        }
}

// ReadMessage returns the next message from the stream or an error.
// It ignores empty messages.
func (r *Reader) ReadMessage() (msg *Message, err error) {
        // It's valid for a message to be empty. Clients should ignore these,
        // so we do to be good citizens.
        err = ErrZeroLengthMessage
        for err == ErrZeroLengthMessage {
                var line string
                line, err = r.reader.ReadString('\n')
                if err != nil {
                        return nil, err
                }

                if r.DebugCallback != nil {
                        r.DebugCallback(line)
                }

                // Parse the message from our line
                msg, err = ParseMessage(line)
        }
        return msg, err
}