--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/xmpp/layer2.go	Sun Sep 15 12:00:17 2013 -0600
@@ -0,0 +1,160 @@
+// This layer of the XMPP protocol translates between bytes and XMLish
+// structures.
+
+package xmpp
+
+import (
+	"io"
+	"reflect"
+	"encoding/xml"
+	"fmt"
+	"strings"
+)
+
+func readXml(r io.Reader, ch chan<- interface{},
+	extStanza map[xml.Name]reflect.Type) {
+	if _, ok := Debug.(*noLog); !ok {
+		pr, pw := io.Pipe()
+		go tee(r, pw, "S: ")
+		r = pr
+	}
+	defer close(ch)
+
+	// This trick loads our namespaces into the parser.
+	nsstr := fmt.Sprintf(`<a xmlns="%s" xmlns:stream="%s">`,
+		NsClient, NsStream)
+	nsrdr := strings.NewReader(nsstr)
+	p := xml.NewDecoder(io.MultiReader(nsrdr, r))
+	p.Token()
+
+Loop:
+	for {
+		// Sniff the next token on the stream.
+		t, err := p.Token()
+		if t == nil {
+			if err != io.EOF {
+				Warn.Logf("read: %s", err)
+			}
+			break
+		}
+		var se xml.StartElement
+		var ok bool
+		if se, ok = t.(xml.StartElement); !ok {
+			continue
+		}
+
+		// Allocate the appropriate structure for this token.
+		var obj interface{}
+		switch se.Name.Space + " " + se.Name.Local {
+		case NsStream + " stream":
+			st, err := parseStream(se)
+			if err != nil {
+				Warn.Logf("unmarshal stream: %s", err)
+				break Loop
+			}
+			ch <- st
+			continue
+		case "stream error", NsStream + " error":
+			obj = &streamError{}
+		case NsStream + " features":
+			obj = &Features{}
+		case NsTLS + " proceed", NsTLS + " failure":
+			obj = &starttls{}
+		case NsSASL + " challenge", NsSASL + " failure",
+			NsSASL + " success":
+			obj = &auth{}
+		case NsClient + " iq":
+			obj = &Iq{}
+		case NsClient + " message":
+			obj = &Message{}
+		case NsClient + " presence":
+			obj = &Presence{}
+		default:
+			obj = &Generic{}
+			Info.Logf("Ignoring unrecognized: %s %s", se.Name.Space,
+				se.Name.Local)
+		}
+
+		// Read the complete XML stanza.
+		err = p.DecodeElement(obj, &se)
+		if err != nil {
+			Warn.Logf("unmarshal: %s", err)
+			break Loop
+		}
+
+		// If it's a Stanza, we try to unmarshal its innerxml
+		// into objects of the appropriate respective
+		// types. This is specified by our extensions.
+		if st, ok := obj.(Stanza); ok {
+			err = parseExtended(st.GetHeader(), extStanza)
+			if err != nil {
+				Warn.Logf("ext unmarshal: %s", err)
+				break Loop
+			}
+		}
+
+		// Put it on the channel.
+		ch <- obj
+	}
+}
+
+func parseExtended(st *Header, extStanza map[xml.Name]reflect.Type) error {
+	// Now parse the stanza's innerxml to find the string that we
+	// can unmarshal this nested element from.
+	reader := strings.NewReader(st.Innerxml)
+	p := xml.NewDecoder(reader)
+	for {
+		t, err := p.Token()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			return err
+		}
+		if se, ok := t.(xml.StartElement); ok {
+			if typ, ok := extStanza[se.Name]; ok {
+				nested := reflect.New(typ).Interface()
+
+				// Unmarshal the nested element and
+				// stuff it back into the stanza.
+				err := p.DecodeElement(nested, &se)
+				if err != nil {
+					return err
+				}
+				st.Nested = append(st.Nested, nested)
+			}
+		}
+	}
+
+	return nil
+}
+
+func writeXml(w io.Writer, ch <-chan interface{}) {
+	if _, ok := Debug.(*noLog); !ok {
+		pr, pw := io.Pipe()
+		go tee(pr, w, "C: ")
+		w = pw
+	}
+	defer func(w io.Writer) {
+		if c, ok := w.(io.Closer); ok {
+			c.Close()
+		}
+	}(w)
+
+	enc := xml.NewEncoder(w)
+
+	for obj := range ch {
+		if st, ok := obj.(*stream); ok {
+			_, err := w.Write([]byte(st.String()))
+			if err != nil {
+				Warn.Logf("write: %s", err)
+			}
+		} else {
+			err := enc.Encode(obj)
+			if err != nil {
+				Warn.Logf("marshal: %s", err)
+				break
+			}
+		}
+	}
+}