Official Go implementation of the Ethereum protocol
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go-ethereum/accounts/keystore/watch.go

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// 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/>.
//go:build (darwin && !ios && cgo) || freebsd || (linux && !arm64) || netbsd || solaris
// +build darwin,!ios,cgo freebsd linux,!arm64 netbsd solaris
package keystore
import (
"time"
"github.com/ethereum/go-ethereum/log"
"github.com/rjeczalik/notify"
)
type watcher struct {
ac *accountCache
running bool // set to true when runloop begins
runEnded bool // set to true when runloop ends
starting bool // set to true prior to runloop starting
ev chan notify.EventInfo
quit chan struct{}
}
func newWatcher(ac *accountCache) *watcher {
return &watcher{
ac: ac,
ev: make(chan notify.EventInfo, 10),
quit: make(chan struct{}),
}
}
// enabled returns false on systems not supported.
func (*watcher) enabled() bool { return true }
// 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.runEnded = true
w.ac.mu.Unlock()
}()
logger := log.New("path", w.ac.keydir)
if err := notify.Watch(w.ac.keydir, w.ev, notify.All); err != nil {
logger.Trace("Failed to watch keystore folder", "err", err)
return
}
defer notify.Stop(w.ev)
logger.Trace("Started watching keystore folder")
defer logger.Trace("Stopped watching keystore folder")
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 (
debounceDuration = 500 * time.Millisecond
rescanTriggered = false
debounce = time.NewTimer(0)
)
// Ignore initial trigger
if !debounce.Stop() {
<-debounce.C
}
defer debounce.Stop()
for {
select {
case <-w.quit:
return
case <-w.ev:
// Trigger the scan (with delay), if not already triggered
if !rescanTriggered {
debounce.Reset(debounceDuration)
rescanTriggered = true
}
case <-debounce.C:
w.ac.scanAccounts()
rescanTriggered = false
}
}
}