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/*
* Copyright (C) 2017 ~ 2018 Deepin Technology Co., Ltd.
*
* Author: jouyouyun <jouyouwen717@gmail.com>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package tasker
import (
"fmt"
"reflect"
"sync"
"time"
)
type DelayTask struct {
timer *time.Timer
handler reflect.Value
argsType []reflect.Type
duration time.Duration
termination chan struct{}
locker sync.Mutex
}
func NewDelayTask(duration time.Duration,
cb interface{}) (*DelayTask, error) {
handler, argsType, err := handleFuncSignature(cb)
if err != nil {
return nil, err
}
return &DelayTask{
handler: *handler,
argsType: argsType,
duration: duration,
}, nil
}
func (task *DelayTask) Start(args ...interface{}) error {
// if started, stop it, else nothing to do
task.Stop()
task.locker.Lock()
defer task.locker.Unlock()
if len(task.argsType) != len(args) {
return fmt.Errorf("argument length expected %d, but got %d",
len(task.argsType), len(args))
}
// check each arg type
for i, t := range task.argsType {
t0 := reflect.TypeOf(args[i])
if t != t0 {
return fmt.Errorf("args[%d] type expected %s, but got %s",
i, t, t0)
}
}
var values = make([]reflect.Value, len(args))
for i, v := range args {
values[i] = reflect.ValueOf(v)
}
task.doStart(values)
return nil
}
func (task *DelayTask) doStart(values []reflect.Value) {
task.termination = make(chan struct{})
task.timer = time.NewTimer(task.duration)
go func() {
exit := task.termination
timer := task.timer
select {
case <-exit:
return
case <-timer.C:
task.handler.Call(values)
return
}
}()
}
func (task *DelayTask) Stop() {
task.locker.Lock()
defer task.locker.Unlock()
if task.termination != nil {
close(task.termination)
task.termination = nil
// TODO: delete
time.Sleep(time.Millisecond * 50)
}
if task.timer != nil {
task.timer.Stop()
}
}
func handleFuncSignature(f interface{}) (*reflect.Value,
[]reflect.Type, error) {
fn := reflect.ValueOf(f)
if fn.Kind() != reflect.Func {
return nil, nil, fmt.Errorf("not a function")
}
fnType := fn.Type()
fnNum := fnType.NumIn()
argTypes := make([]reflect.Type, fnNum)
for i := 0; i < fnNum; i++ {
argTypes[i] = fnType.In(i)
}
return &fn, argTypes, nil
}
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