Method addIfNotPresent

tools/cache/delta_fifo.go:248–257

addIfNotPresent inserts deltas under id if it does not exist, and assumes the caller already holds the fifo lock.

(id string, deltas Deltas)

// addIfNotPresent inserts deltas under id if it does not exist, and assumes the caller
// already holds the fifo lock.
func (f *DeltaFIFO) addIfNotPresent(id string, deltas Deltas) {
	f.populated = true
	if _, exists := f.items[id]; exists {
		return
	}

	f.queue = append(f.queue, id)
	f.items[id] = deltas
	f.cond.Broadcast()
}

// re-listing and watching can deliver the same update multiple times in any
// order. This will combine the most recent two deltas if they are the same.