component.go

package xco

import (
	"encoding/xml"
	"log"
	"net"

	"github.com/pkg/errors"

	"context"
)

type stateFn func() (stateFn, error)

// A Component is an instance of a Jabber Component (XEP-0114)
type Component struct {
	MessageHandler   MessageHandler
	DiscoInfoHandler DiscoInfoHandler
	PresenceHandler  PresenceHandler
	IqHandler        IqHandler
	UnknownHandler   UnknownElementHandler

	ctx      context.Context
	cancelFn context.CancelFunc

	conn net.Conn
	dec  *xml.Decoder
	enc  *xml.Encoder
	log  *log.Logger

	stateFn stateFn

	sharedSecret string
	name         string
}

func (c *Component) init(o Options) error {
	conn, err := net.Dial("tcp", o.Address)
	if err != nil {
		return err
	}

	c.MessageHandler = noOpMessageHandler
	c.DiscoInfoHandler = noOpDiscoInfoHandler
	c.PresenceHandler = noOpPresenceHandler
	c.IqHandler = noOpIqHandler
	c.UnknownHandler = noOpUnknownHandler

	c.conn = conn
	c.name = o.Name
	c.sharedSecret = o.SharedSecret
	if o.Logger == nil {
		c.dec = xml.NewDecoder(conn)
		c.enc = xml.NewEncoder(conn)
	} else {
		c.log = o.Logger
		c.dec = xml.NewDecoder(newReadLogger(c.log, conn))
		c.enc = xml.NewEncoder(newWriteLogger(c.log, conn))
	}
	c.stateFn = c.handshakeState

	return nil
}

// Close closes the Component
func (c *Component) Close() {
	if c == nil {
		return
	}
	c.cancelFn()
}

// Run runs the component handlers loop and waits for it to finish
func (c *Component) Run() (err error) {

	defer func() {
		c.conn.Close()
	}()

	for {
		if c.stateFn == nil {
			return nil
		}
		c.stateFn, err = c.stateFn()
		if err != nil {
			return err
		}
	}
}

// A Sender is an interface which allows sending of arbitrary objects
// as XML to an XMPP server.
type Sender interface {
	Send(i interface{}) error
}

// Send sends the given pointer struct by serializing it to XML.
func (c *Component) Send(i interface{}) error {
	return errors.Wrap(c.enc.Encode(i), "Error encoding object to XML")
}

// Write implements the io.Writer interface to allow direct writing to the XMPP connection
func (c *Component) Write(b []byte) (int, error) {
	return c.conn.Write(b)
}