Fix SIGSEGV in xmpp_component (#126)

* SIGSEGV in xmpp_component example with Prosody #126

component.go

@@ -7,9 +7,8 @@ import (
 	"encoding/xml"
 	"errors"
 	"fmt"
-	"io"
-
 	"gosrc.io/xmpp/stanza"
+	"io"
 )
 
 type ComponentOptions struct {
@@ -50,7 +49,6 @@ type Component struct {
 
 	// read / write
 	socketProxy io.ReadWriter // TODO
-	decoder     *xml.Decoder
 }
 
 func NewComponent(opts ComponentOptions, r *Router) (*Component, error) {
@@ -90,7 +88,7 @@ func (c *Component) Resume(sm SMState) error {
 	}
 
 	// Check server response for authentication
-	val, err := stanza.NextPacket(c.decoder)
+	val, err := stanza.NextPacket(c.transport.GetDecoder())
 	if err != nil {
 		c.updateState(StatePermanentError)
 		return NewConnError(err, true)
@@ -125,7 +123,7 @@ func (c *Component) SetHandler(handler EventHandler) {
 // Receiver Go routine receiver
 func (c *Component) recv() (err error) {
 	for {
-		val, err := stanza.NextPacket(c.decoder)
+		val, err := stanza.NextPacket(c.transport.GetDecoder())
 		if err != nil {
 			c.updateState(StateDisconnected)
 			return err

component_test.go

@@ -1,9 +1,13 @@
 package xmpp
 
 import (
+	"fmt"
 	"testing"
 )
 
+const testComponentDomain = "localhost"
+const testComponentPort = "15222"
+
 func TestHandshake(t *testing.T) {
 	opts := ComponentOptions{
 		Domain: "test.localhost",
@@ -30,3 +34,41 @@ func TestGenerateHandshake(t *testing.T) {
 func TestStreamManager(t *testing.T) {
 	NewStreamManager(&Component{}, nil)
 }
+
+// Tests that the decoder is properly initialized when connecting a component to a server.
+// The decoder is expected to be built after a valid connection
+// Based on the xmpp_component example.
+func TestDecoder(t *testing.T) {
+	testComponentAddess := fmt.Sprintf("%s:%s", testComponentDomain, testComponentPort)
+	mock := ServerMock{}
+	mock.Start(t, testComponentAddess, handlerConnectSuccess)
+
+	opts := ComponentOptions{
+		TransportConfiguration: TransportConfiguration{
+			Address: testComponentAddess,
+			Domain:  "localhost",
+		},
+		Domain:   testComponentDomain,
+		Secret:   "mypass",
+		Name:     "Test Component",
+		Category: "gateway",
+		Type:     "service",
+	}
+	router := NewRouter()
+	c, err := NewComponent(opts, router)
+	if err != nil {
+		t.Errorf("%+v", err)
+	}
+	c.transport, err = NewComponentTransport(c.ComponentOptions.TransportConfiguration)
+	if err != nil {
+		t.Errorf("%+v", err)
+	}
+	_, err = c.transport.Connect()
+	if err != nil {
+		t.Errorf("%+v", err)
+	}
+	if c.transport.GetDecoder() == nil {
+		t.Errorf("Failed to initialize decoder. Decoder is nil.")
+	}
+
+}

websocket_transport.go

@@ -20,6 +20,7 @@ const pingTimeout = time.Duration(5) * time.Second
 
 var ServerDoesNotSupportXmppOverWebsocket = errors.New("The websocket server does not support the xmpp subprotocol")
 
+// The decoder is expected to be initialized after connecting to a server.
 type WebsocketTransport struct {
 	Config  TransportConfiguration
 	decoder *xml.Decoder

xmpp_transport.go

@@ -14,6 +14,7 @@ import (
 )
 
 // XMPPTransport implements the XMPP native TCP transport
+// The decoder is expected to be initialized after connecting to a server.
 type XMPPTransport struct {
 	openStatement string
 	Config        TransportConfiguration