frp/vendor/github.com/fatedier/kcp-go/updater.go

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2017-10-24 22:53:20 +08:00
package kcp
import (
"container/heap"
"sync"
"time"
)
var updater updateHeap
func init() {
updater.init()
go updater.updateTask()
}
// entry contains a session update info
type entry struct {
ts time.Time
s *UDPSession
}
// a global heap managed kcp.flush() caller
type updateHeap struct {
entries []entry
mu sync.Mutex
chWakeUp chan struct{}
}
func (h *updateHeap) Len() int { return len(h.entries) }
func (h *updateHeap) Less(i, j int) bool { return h.entries[i].ts.Before(h.entries[j].ts) }
func (h *updateHeap) Swap(i, j int) {
h.entries[i], h.entries[j] = h.entries[j], h.entries[i]
h.entries[i].s.updaterIdx = i
h.entries[j].s.updaterIdx = j
}
func (h *updateHeap) Push(x interface{}) {
h.entries = append(h.entries, x.(entry))
n := len(h.entries)
h.entries[n-1].s.updaterIdx = n - 1
}
func (h *updateHeap) Pop() interface{} {
n := len(h.entries)
x := h.entries[n-1]
h.entries[n-1].s.updaterIdx = -1
h.entries[n-1] = entry{} // manual set nil for GC
h.entries = h.entries[0 : n-1]
return x
}
func (h *updateHeap) init() {
h.chWakeUp = make(chan struct{}, 1)
}
func (h *updateHeap) addSession(s *UDPSession) {
h.mu.Lock()
heap.Push(h, entry{time.Now(), s})
h.mu.Unlock()
h.wakeup()
}
func (h *updateHeap) removeSession(s *UDPSession) {
h.mu.Lock()
if s.updaterIdx != -1 {
heap.Remove(h, s.updaterIdx)
}
h.mu.Unlock()
}
func (h *updateHeap) wakeup() {
select {
case h.chWakeUp <- struct{}{}:
default:
}
}
func (h *updateHeap) updateTask() {
var timer <-chan time.Time
for {
select {
case <-timer:
case <-h.chWakeUp:
}
h.mu.Lock()
hlen := h.Len()
now := time.Now()
for i := 0; i < hlen; i++ {
entry := heap.Pop(h).(entry)
if now.After(entry.ts) {
entry.ts = now.Add(entry.s.update())
heap.Push(h, entry)
} else {
heap.Push(h, entry)
break
}
}
if hlen > 0 {
timer = time.After(h.entries[0].ts.Sub(now))
}
h.mu.Unlock()
}
}