go-pulse/accounts/keystore/watch.go
2023-11-20 08:44:05 +01:00

135 lines
3.5 KiB
Go

// 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 (
"os"
"time"
"github.com/ethereum/go-ethereum/log"
"github.com/fsnotify/fsnotify"
)
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
quit chan struct{}
}
func newWatcher(ac *accountCache) *watcher {
return &watcher{
ac: ac,
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)
// Create new watcher.
watcher, err := fsnotify.NewWatcher()
if err != nil {
log.Error("Failed to start filesystem watcher", "err", err)
return
}
defer watcher.Close()
if err := watcher.Add(w.ac.keydir); err != nil {
if !os.IsNotExist(err) {
logger.Warn("Failed to watch keystore folder", "err", err)
}
return
}
logger.Trace("Started watching keystore folder", "folder", w.ac.keydir)
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 _, ok := <-watcher.Events:
if !ok {
return
}
// Trigger the scan (with delay), if not already triggered
if !rescanTriggered {
debounce.Reset(debounceDuration)
rescanTriggered = true
}
// The fsnotify library does provide more granular event-info, it
// would be possible to refresh individual affected files instead
// of scheduling a full rescan. For most cases though, the
// full rescan is quick and obviously simplest.
case err, ok := <-watcher.Errors:
if !ok {
return
}
log.Info("Filesystem watcher error", "err", err)
case <-debounce.C:
w.ac.scanAccounts()
rescanTriggered = false
}
}
}