func (q *AliveHookQueue) loop(initial *State) {
defer q.tomb.Done()
defer watcher.Stop(q.w, &q.tomb)
// Consume initial event, and reconcile with initial state, by inserting
// a new RelationUnitsChange before the initial event, which schedules
// every missing unit for immediate departure before anything else happens
// (apart from a single potential required post-joined changed event).
ch1, ok := <-q.w.Changes()
if !ok {
q.tomb.Kill(watcher.MustErr(q.w))
return
}
if len(ch1.Departed) != 0 {
panic("AliveHookQueue must be started with a fresh RelationUnitsWatcher")
}
q.changedPending = initial.ChangedPending
ch0 := state.RelationUnitsChange{}
for unit, version := range initial.Members {
q.info[unit] = &unitInfo{
unit: unit,
version: version,
joined: true,
}
if _, found := ch1.Changed[unit]; !found {
ch0.Departed = append(ch0.Departed, unit)
}
}
q.update(ch0)
q.update(ch1)
var next hook.Info
var out chan<- hook.Info
for {
if q.empty() {
out = nil
} else {
out = q.out
next = q.next()
}
select {
case <-q.tomb.Dying():
return
case ch, ok := <-q.w.Changes():
if !ok {
q.tomb.Kill(watcher.MustErr(q.w))
return
}
q.update(ch)
case out <- next:
q.pop()
}
}
}
func (d send) check(c *C, in chan state.RelationUnitsChange, out chan hook.Info) {
ruc := state.RelationUnitsChange{Changed: map[string]state.UnitSettings{}}
for name, version := range d.changed {
ruc.Changed[name] = state.UnitSettings{
Version: version,
Settings: settings(name, version),
}
}
for _, name := range d.departed {
ruc.Departed = append(ruc.Departed, name)
}
in <- ruc
}