func (z *zeroconf) updatePrinterTXT(name, ty, url, id string, online bool) error {
z.spMutex.Lock()
defer z.spMutex.Unlock()
r, exists := z.printers[name]
if !exists {
return fmt.Errorf("printer %s cannot be updated for Avahi publishing; it was never added", name)
}
r.ty = ty
r.url = url
r.id = id
r.online = online
if z.state == C.AVAHI_CLIENT_S_RUNNING && r.group != nil {
txt := prepareTXT(ty, url, id, online)
defer C.avahi_string_list_free(txt)
C.avahi_threaded_poll_lock(z.threadedPoll)
defer C.avahi_threaded_poll_unlock(z.threadedPoll)
if errstr := C.updateAvahiGroup(z.threadedPoll, r.group, r.name, txt); errstr != nil {
err := fmt.Errorf("Failed to update Avahi group: %s", C.GoString(errstr))
return err
}
}
z.printers[name] = r
return nil
}
func (z *zeroconf) addPrinter(name string, port uint16, ty, url, id string, online bool) error {
r := record{
name: C.CString(name),
port: port,
ty: ty,
url: url,
id: id,
online: online,
}
z.spMutex.Lock()
defer z.spMutex.Unlock()
if _, exists := z.printers[name]; exists {
return fmt.Errorf("printer %s was already added to Avahi publishing", name)
}
if z.state == C.AVAHI_CLIENT_S_RUNNING {
txt := prepareTXT(ty, url, id, online)
defer C.avahi_string_list_free(txt)
C.avahi_threaded_poll_lock(z.threadedPoll)
defer C.avahi_threaded_poll_unlock(z.threadedPoll)
if errstr := C.addAvahiGroup(z.threadedPoll, z.client, &r.group, r.name, C.ushort(r.port), txt); errstr != nil {
err := fmt.Errorf("Failed to add Avahi group: %s", C.GoString(errstr))
return err
}
}
z.printers[name] = r
return nil
}
// handleClientStateChange makes clean transitions as the connection with
// avahi-daemon changes.
//export handleClientStateChange
func handleClientStateChange(client *C.AvahiClient, newState C.AvahiClientState, userdata unsafe.Pointer) {
z := instance
z.spMutex.Lock()
defer z.spMutex.Unlock()
// Name conflict.
if newState == C.AVAHI_CLIENT_S_COLLISION {
log.Warning("Avahi reports a host name collision.")
}
// Transition from not connecting to connecting. Warn in logs.
if newState == C.AVAHI_CLIENT_CONNECTING {
log.Warning("Cannot find Avahi daemon. Is it running?")
}
// Transition from running to not running. Free all groups.
if newState != C.AVAHI_CLIENT_S_RUNNING {
log.Info("Local printing disabled (Avahi client is not running).")
for name, r := range z.printers {
if r.group != nil {
if errstr := C.removeAvahiGroup(z.threadedPoll, r.group); errstr != nil {
err := errors.New(C.GoString(errstr))
log.Errorf("Failed to remove Avahi group: %s", err)
}
r.group = nil
z.printers[name] = r
}
}
}
// Transition from not running to running. Recreate all groups.
if newState == C.AVAHI_CLIENT_S_RUNNING {
log.Info("Local printing enabled (Avahi client is running).")
for name, r := range z.printers {
txt := prepareTXT(r.ty, r.url, r.id, r.online)
defer C.avahi_string_list_free(txt)
if errstr := C.addAvahiGroup(z.threadedPoll, z.client, &r.group, r.name, C.ushort(r.port), txt); errstr != nil {
err := errors.New(C.GoString(errstr))
log.Errorf("Failed to add Avahi group: %s", err)
}
z.printers[name] = r
}
}
// Transition from not failure to failure. Recreate thread poll and client.
if newState == C.AVAHI_CLIENT_FAILURE {
z.restart <- struct{}{}
}
z.state = newState
}