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package amqp
import "sync"
// confirms resequences and notifies one or multiple publisher confirmation listeners
type confirms struct {
m sync.Mutex
listeners []chan Confirmation
sequencer map[uint64]Confirmation
published uint64
expecting uint64
}
// newConfirms allocates a confirms
func newConfirms() *confirms {
return &confirms{
sequencer: map[uint64]Confirmation{},
published: 0,
expecting: 1,
}
}
func (c *confirms) Listen(l chan Confirmation) {
c.m.Lock()
defer c.m.Unlock()
c.listeners = append(c.listeners, l)
}
// publish increments the publishing counter
func (c *confirms) Publish() uint64 {
c.m.Lock()
defer c.m.Unlock()
c.published++
return c.published
}
// confirm confirms one publishing, increments the expecting delivery tag, and
// removes bookkeeping for that delivery tag.
func (c *confirms) confirm(confirmation Confirmation) {
delete(c.sequencer, c.expecting)
c.expecting++
for _, l := range c.listeners {
l <- confirmation
}
}
// resequence confirms any out of order delivered confirmations
func (c *confirms) resequence() {
for c.expecting <= c.published {
sequenced, found := c.sequencer[c.expecting]
if !found {
return
}
c.confirm(sequenced)
}
}
// one confirms one publishing and all following in the publishing sequence
func (c *confirms) One(confirmed Confirmation) {
c.m.Lock()
defer c.m.Unlock()
if c.expecting == confirmed.DeliveryTag {
c.confirm(confirmed)
} else {
c.sequencer[confirmed.DeliveryTag] = confirmed
}
c.resequence()
}
// multiple confirms all publishings up until the delivery tag
func (c *confirms) Multiple(confirmed Confirmation) {
c.m.Lock()
defer c.m.Unlock()
for c.expecting <= confirmed.DeliveryTag {
c.confirm(Confirmation{c.expecting, confirmed.Ack})
}
c.resequence()
}
// Close closes all listeners, discarding any out of sequence confirmations
func (c *confirms) Close() error {
c.m.Lock()
defer c.m.Unlock()
for _, l := range c.listeners {
close(l)
}
c.listeners = nil
return nil
}
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