github.com/linapex/ethereum-dpos-chinese@v0.0.0-20190316121959-b78b3a4a1ece/accounts/keystore/watch.go (about)

     1  
     2  //<developer>
     3  //    <name>linapex 曹一峰</name>
     4  //    <email>linapex@163.com</email>
     5  //    <wx>superexc</wx>
     6  //    <qqgroup>128148617</qqgroup>
     7  //    <url>https://jsq.ink</url>
     8  //    <role>pku engineer</role>
     9  //    <date>2019-03-16 12:09:27</date>
    10  //</624342586072502272>
    11  
    12  
    13  //+建立达尔文，！iOS Freebsd Linux，！ARM64 NetBSD Solaris
    14  
    15  package keystore
    16  
    17  import (
    18  	"time"
    19  
    20  	"github.com/ethereum/go-ethereum/log"
    21  	"github.com/rjeczalik/notify"
    22  )
    23  
    24  type watcher struct {
    25  	ac       *accountCache
    26  	starting bool
    27  	running  bool
    28  	ev       chan notify.EventInfo
    29  	quit     chan struct{}
    30  }
    31  
    32  func newWatcher(ac *accountCache) *watcher {
    33  	return &watcher{
    34  		ac:   ac,
    35  		ev:   make(chan notify.EventInfo, 10),
    36  		quit: make(chan struct{}),
    37  	}
    38  }
    39  
    40  //在后台启动观察程序循环。
    41  //如果尚未进行，请在后台启动观察程序。
    42  //呼叫方必须持有W.AC.MU。
    43  func (w *watcher) start() {
    44  	if w.starting || w.running {
    45  		return
    46  	}
    47  	w.starting = true
    48  	go w.loop()
    49  }
    50  
    51  func (w *watcher) close() {
    52  	close(w.quit)
    53  }
    54  
    55  func (w *watcher) loop() {
    56  	defer func() {
    57  		w.ac.mu.Lock()
    58  		w.running = false
    59  		w.starting = false
    60  		w.ac.mu.Unlock()
    61  	}()
    62  	logger := log.New("path", w.ac.keydir)
    63  
    64  	if err := notify.Watch(w.ac.keydir, w.ev, notify.All); err != nil {
    65  		logger.Trace("Failed to watch keystore folder", "err", err)
    66  		return
    67  	}
    68  	defer notify.Stop(w.ev)
    69  	logger.Trace("Started watching keystore folder")
    70  	defer logger.Trace("Stopped watching keystore folder")
    71  
    72  	w.ac.mu.Lock()
    73  	w.running = true
    74  	w.ac.mu.Unlock()
    75  
    76  //等待文件系统事件并重新加载。
    77  //当事件发生时，重新加载调用会延迟一点，以便
    78  //多个事件快速到达只会导致一次重新加载。
    79  	var (
    80  		debounceDuration = 500 * time.Millisecond
    81  		rescanTriggered  = false
    82  		debounce         = time.NewTimer(0)
    83  	)
    84  //忽略初始触发器
    85  	if !debounce.Stop() {
    86  		<-debounce.C
    87  	}
    88  	defer debounce.Stop()
    89  	for {
    90  		select {
    91  		case <-w.quit:
    92  			return
    93  		case <-w.ev:
    94  //触发扫描（延迟），如果尚未触发
    95  			if !rescanTriggered {
    96  				debounce.Reset(debounceDuration)
    97  				rescanTriggered = true
    98  			}
    99  		case <-debounce.C:
   100  			w.ac.scanAccounts()
   101  			rescanTriggered = false
   102  		}
   103  	}
   104  }
   105