init

dtask/job.go

@@ -0,0 +1,99 @@
+package dtask
+
+import (
+	"gitlab.33.cn/chat/im/dtask/pkg/rbtree"
+	"log"
+	"runtime/debug"
+	"sync/atomic"
+	"time"
+)
+
+/*
+This code is based on the following resources:
+source code:	https://github.com/alex023/clock.git
+*/
+// Job External access interface for timed tasks
+type Job interface {
+	C() <-chan Job     //C Get a Chan，which can get message if Job is executed
+	Count() uint64     //计数器，表示已执行（或触发）的次数
+	Max() uint64       //允许执行的最大次数
+	Cancel()           //撤销加载的任务，不再定时执行
+	isAvailable() bool //return true，if job not action or not cancel
+}
+
+// jobItem implementation of  "Job" interface and "rbtree.Item" interface
+type jobItem struct {
+	id           uint64        //唯一键值，内部由管理器生成，以区分同一时刻的不同任务事件
+	actionCount  uint64        //计数器，表示已执行（或触发）的次数
+	actionMax    uint64        //允许执行的最大次数
+	intervalTime time.Duration //间隔时间
+	createTime   time.Time     //创建时间，略有误差
+	actionTime   time.Time     //计算得出的最近一次执行时间点
+	fn           func()        //事件函数
+	msgChan      chan Job      //消息通道，执行时，控制器通过该通道向外部传递消息
+	cancelFlag   int32
+	clock        *Clock
+}
+
+// Less Based rbtree ，implements Item interface for sort
+func (je jobItem) Less(another rbtree.Item) bool {
+	item, ok := another.(*jobItem)
+	if !ok {
+		return false
+	}
+	if !je.actionTime.Equal(item.actionTime) {
+		return je.actionTime.Before(item.actionTime)
+	}
+	return je.id < item.id
+}
+
+func (je *jobItem) C() <-chan Job {
+	return je.msgChan
+}
+
+func (je *jobItem) action(async bool) {
+	je.actionCount++
+	if async {
+		go safeCall(je.fn)
+	} else {
+		safeCall(je.fn)
+	}
+	select {
+	case je.msgChan <- je:
+	default:
+		//some times,client should not receive msgChan,so must discard jobItem when blocking
+	}
+}
+
+func (je *jobItem) Cancel() {
+	if atomic.CompareAndSwapInt32(&je.cancelFlag, 0, 1) {
+		je.clock.rmJob(je)
+		je.innerCancel()
+	}
+}
+func (je *jobItem) isAvailable() bool {
+	return je.cancelFlag == 0
+}
+func (je *jobItem) innerCancel() {
+	je.clock = nil
+	close(je.msgChan)
+}
+
+// Count implement for Job
+func (je jobItem) Count() uint64 {
+	return je.actionCount
+}
+
+// Max implement for Job
+func (je jobItem) Max() uint64 {
+	return je.actionMax
+}
+func safeCall(fn func()) {
+	defer func() {
+		if err := recover(); err != nil {
+			log.Printf("[clock] recovering reason is %+v. More detail:", err)
+			log.Println(string(debug.Stack()))
+		}
+	}()
+	fn()
+}