accounts, cmd, eth, internal, mobile, node: split account backends

accounts/keystore/watch.go

@@ -0,0 +1,113 @@
+// Copyright 2016 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum 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 go-ethereum 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 go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// +build darwin,!ios freebsd linux,!arm64 netbsd solaris
+
+package keystore
+
+import (
+	"time"
+
+	"github.com/ethereum/go-ethereum/logger"
+	"github.com/ethereum/go-ethereum/logger/glog"
+	"github.com/rjeczalik/notify"
+)
+
+type watcher struct {
+	ac       *addressCache
+	starting bool
+	running  bool
+	ev       chan notify.EventInfo
+	quit     chan struct{}
+}
+
+func newWatcher(ac *addressCache) *watcher {
+	return &watcher{
+		ac:   ac,
+		ev:   make(chan notify.EventInfo, 10),
+		quit: make(chan struct{}),
+	}
+}
+
+// starts the watcher loop in the background.
+// Start a watcher in the background if that's not already in progress.
+// The caller must hold w.ac.mu.
+func (w *watcher) start() {
+	if w.starting || w.running {
+		return
+	}
+	w.starting = true
+	go w.loop()
+}
+
+func (w *watcher) close() {
+	close(w.quit)
+}
+
+func (w *watcher) loop() {
+	defer func() {
+		w.ac.mu.Lock()
+		w.running = false
+		w.starting = false
+		w.ac.mu.Unlock()
+	}()
+
+	err := notify.Watch(w.ac.keydir, w.ev, notify.All)
+	if err != nil {
+		glog.V(logger.Detail).Infof("can't watch %s: %v", w.ac.keydir, err)
+		return
+	}
+	defer notify.Stop(w.ev)
+	glog.V(logger.Detail).Infof("now watching %s", w.ac.keydir)
+	defer glog.V(logger.Detail).Infof("no longer watching %s", w.ac.keydir)
+
+	w.ac.mu.Lock()
+	w.running = true
+	w.ac.mu.Unlock()
+
+	// Wait for file system events and reload.
+	// When an event occurs, the reload call is delayed a bit so that
+	// multiple events arriving quickly only cause a single reload.
+	var (
+		debounce          = time.NewTimer(0)
+		debounceDuration  = 500 * time.Millisecond
+		inCycle, hadEvent bool
+	)
+	defer debounce.Stop()
+	for {
+		select {
+		case <-w.quit:
+			return
+		case <-w.ev:
+			if !inCycle {
+				debounce.Reset(debounceDuration)
+				inCycle = true
+			} else {
+				hadEvent = true
+			}
+		case <-debounce.C:
+			w.ac.mu.Lock()
+			w.ac.reload()
+			w.ac.mu.Unlock()
+			if hadEvent {
+				debounce.Reset(debounceDuration)
+				inCycle, hadEvent = true, false
+			} else {
+				inCycle, hadEvent = false, false
+			}
+		}
+	}
+}