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// Copyright 2018 The dexon-consensus-core Authors
// This file is part of the dexon-consensus-core library.
//
// The dexon-consensus-core library is free software: you can redistribute it
// and/or modify it under the terms of the GNU Lesser General Public License as
// published by the Free Software Foundation, either version 3 of the License,
// or (at your option) any later version.
//
// The dexon-consensus-core library is distributed in the hope that it will be
// useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
// General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the dexon-consensus-core library. If not, see
// <http://www.gnu.org/licenses/>.
package common
import (
"container/heap"
"sync"
"time"
)
type timeEventFn func(time.Time)
type timeEvent struct {
t time.Time
fn timeEventFn
}
// timeEvents implements a Min-Heap structure.
type timeEvents []timeEvent
func (h timeEvents) Len() int { return len(h) }
func (h timeEvents) Less(i, j int) bool { return h[i].t.Before(h[j].t) }
func (h timeEvents) Swap(i, j int) { h[i], h[j] = h[j], h[i] }
func (h *timeEvents) Push(x interface{}) {
*h = append(*h, x.(timeEvent))
}
func (h *timeEvents) Pop() interface{} {
old := *h
n := len(old)
x := old[n-1]
*h = old[0 : n-1]
return x
}
// Event implements the Observer pattern.
type Event struct {
timeEvents timeEvents
timeEventsLock sync.Mutex
}
// NewEvent creates a new event instance.
func NewEvent() *Event {
te := timeEvents{}
heap.Init(&te)
return &Event{
timeEvents: te,
}
}
// RegisterTime to get notified on and after specific time.
func (e *Event) RegisterTime(t time.Time, fn timeEventFn) {
e.timeEventsLock.Lock()
defer e.timeEventsLock.Unlock()
heap.Push(&e.timeEvents, timeEvent{
t: t,
fn: fn,
})
}
// NotifyTime and trigger function callback.
func (e *Event) NotifyTime(t time.Time) {
fns := func() (fns []timeEventFn) {
e.timeEventsLock.Lock()
defer e.timeEventsLock.Unlock()
if len(e.timeEvents) == 0 {
return
}
for !t.Before(e.timeEvents[0].t) {
te := heap.Pop(&e.timeEvents).(timeEvent)
fns = append(fns, te.fn)
if len(e.timeEvents) == 0 {
return
}
}
return
}()
for _, fn := range fns {
fn(t)
}
}
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