diff -r f464f14e39a7 -r 367e76b3028e xmpp/roster.go
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/xmpp/roster.go	Sat Sep 07 10:04:44 2013 -0700
@@ -0,0 +1,155 @@
+// Copyright 2011 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package xmpp
+
+// This file contains support for roster management, RFC 3921, Section 7.
+
+import (
+	"encoding/xml"
+)
+
+// Roster query/result
+type RosterQuery struct {
+	XMLName xml.Name     `xml:"jabber:iq:roster query"`
+	Item    []RosterItem `xml:"item"`
+}
+
+// See RFC 3921, Section 7.1.
+type RosterItem struct {
+	XMLName      xml.Name `xml:"jabber:iq:roster item"`
+	Jid          string   `xml:"jid,attr"`
+	Subscription string   `xml:"subscription,attr"`
+	Name         string   `xml:"name,attr"`
+	Group        []string
+}
+
+type rosterCb struct {
+	id string
+	cb func()
+}
+
+type Roster struct {
+	Extension
+	get chan []RosterItem
+	callbacks chan rosterCb
+	toServer chan Stanza
+}
+
+type rosterClient struct {
+	rosterChan   <-chan []RosterItem
+	rosterUpdate chan<- RosterItem
+}
+
+// Implicitly becomes part of NewClient's extStanza arg.
+func newRosterQuery(name *xml.Name) interface{} {
+	return &RosterQuery{}
+}
+
+func (r *Roster) rosterMgr(upd <-chan Stanza) {
+	roster := make(map[string]RosterItem)
+	waits := make(map[string]func())
+	var snapshot []RosterItem
+	for {
+		select {
+		case stan, ok := <- upd:
+			if !ok {
+				return
+			}
+			hdr := stan.GetHeader()
+			if f := waits[hdr.Id] ; f != nil {
+				delete(waits, hdr.Id)
+				f()
+			}
+			iq, ok := stan.(*Iq)
+			if iq.Type != "set" {
+				continue
+			}
+			var rq *RosterQuery
+			for _, ele := range iq.Nested {
+				if q, ok := ele.(*RosterQuery); ok {
+					rq = q
+					break
+				}
+			}
+			if rq == nil {
+				continue
+			}
+			for _, item := range rq.Item {
+				roster[item.Jid] = item
+			}
+			snapshot = []RosterItem{}
+			for _, ri := range roster {
+				snapshot = append(snapshot, ri)
+			}
+		case r.get <- snapshot:
+		case cb := <- r.callbacks:
+			waits[cb.id] = cb.cb
+		}
+	}
+}
+
+func (r *Roster) makeFilters() (Filter, Filter) {
+	rosterUpdate := make(chan Stanza)
+	go r.rosterMgr(rosterUpdate)
+	recv := func(in <-chan Stanza, out chan<- Stanza) {
+		defer close(out)
+		for stan := range in {
+			rosterUpdate <- stan
+			out <- stan
+		}
+	}
+	send := func(in <-chan Stanza, out chan<- Stanza) {
+		defer close(out)
+		for {
+			select {
+			case stan, ok := <- in:
+				if !ok {
+					return
+				}
+				out <- stan
+			case stan := <- r.toServer:
+				out <- stan
+			}
+		}
+	}
+	return recv, send
+}
+
+func newRosterExt() *Roster {
+	r := Roster{}
+	r.StanzaHandlers = make(map[string]func(*xml.Name) interface{})
+	r.StanzaHandlers[NsRoster] = newRosterQuery
+	r.RecvFilter, r.SendFilter = r.makeFilters()
+	r.get = make(chan []RosterItem)
+	r.callbacks = make(chan rosterCb)
+	r.toServer = make(chan Stanza)
+	return &r
+}
+
+// Return the most recent snapshot of the roster status. This is
+// updated automatically as roster updates are received from the
+// server, but especially in response to calls to Update().
+func (r *Roster) Get() []RosterItem {
+	return <-r.get
+}
+
+// Synchronously fetch this entity's roster from the server and cache
+// that information. The client can access the roster by watching for
+// RosterQuery objects or by calling Get().
+func (r *Roster) Update() {
+	iq := &Iq{Header: Header{Type: "get", Id: NextId(),
+		Nested: []interface{}{RosterQuery{}}}}
+	waitchan := make(chan int)
+	done := func() {
+		close(waitchan)
+	}
+	r.waitFor(iq.Id, done)
+	r.toServer <- iq
+	<-waitchan
+}
+
+func (r *Roster) waitFor(id string, cb func()) {
+	r.callbacks <- rosterCb{id: id, cb: cb}
+}