// defaultConfigDir returns the default configuration directory, as figured
// out by various the environment variables present on each platform, or dies
// trying.
func defaultConfigDir() string {
	switch runtime.GOOS {
	case "windows":
		if p := os.Getenv("LocalAppData"); p != "" {
			return filepath.Join(p, "Syncthing")
		}
		return filepath.Join(os.Getenv("AppData"), "Syncthing")

	case "darwin":
		dir, err := osutil.ExpandTilde("~/Library/Application Support/Syncthing")
		if err != nil {
			l.Fatalln(err)
		}
		return dir

	default:
		if xdgCfg := os.Getenv("XDG_CONFIG_HOME"); xdgCfg != "" {
			return filepath.Join(xdgCfg, "syncthing")
		}
		dir, err := osutil.ExpandTilde("~/.config/syncthing")
		if err != nil {
			l.Fatalln(err)
		}
		return dir
	}
}

func (s *apiService) getSystemBrowse(w http.ResponseWriter, r *http.Request) {
	qs := r.URL.Query()
	current := qs.Get("current")
	if current == "" {
		if roots, err := osutil.GetFilesystemRoots(); err == nil {
			sendJSON(w, roots)
		} else {
			http.Error(w, err.Error(), 500)
		}
		return
	}
	search, _ := osutil.ExpandTilde(current)
	pathSeparator := string(os.PathSeparator)
	if strings.HasSuffix(current, pathSeparator) && !strings.HasSuffix(search, pathSeparator) {
		search = search + pathSeparator
	}
	subdirectories, _ := osutil.Glob(search + "*")
	ret := make([]string, 0, len(subdirectories))
	for _, subdirectory := range subdirectories {
		info, err := os.Stat(subdirectory)
		if err == nil && info.IsDir() {
			ret = append(ret, subdirectory+pathSeparator)
		}
	}

	sendJSON(w, ret)
}

func (f FolderConfiguration) Path() string {
	// This is intentionally not a pointer method, because things like
	// cfg.Folders["default"].Path() should be valid.

	// Attempt tilde expansion; leave unchanged in case of error
	if path, err := osutil.ExpandTilde(f.RawPath); err == nil {
		f.RawPath = path
	}

	// Attempt absolutification; leave unchanged in case of error
	if !filepath.IsAbs(f.RawPath) {
		// Abs() looks like a fairly expensive syscall on Windows, while
		// IsAbs() is a whole bunch of string mangling. I think IsAbs() may be
		// somewhat faster in the general case, hence the outer if...
		if path, err := filepath.Abs(f.RawPath); err == nil {
			f.RawPath = path
		}
	}

	// Attempt to enable long filename support on Windows. We may still not
	// have an absolute path here if the previous steps failed.
	if runtime.GOOS == "windows" && filepath.IsAbs(f.RawPath) && !strings.HasPrefix(f.RawPath, `\\`) {
		return `\\?\` + f.RawPath
	}

	return f.RawPath
}

func (f *FolderConfiguration) cleanedPath() string {
	cleaned := f.RawPath

	// Attempt tilde expansion; leave unchanged in case of error
	if path, err := osutil.ExpandTilde(cleaned); err == nil {
		cleaned = path
	}

	// Attempt absolutification; leave unchanged in case of error
	if !filepath.IsAbs(cleaned) {
		// Abs() looks like a fairly expensive syscall on Windows, while
		// IsAbs() is a whole bunch of string mangling. I think IsAbs() may be
		// somewhat faster in the general case, hence the outer if...
		if path, err := filepath.Abs(cleaned); err == nil {
			cleaned = path
		}
	}

	// Attempt to enable long filename support on Windows. We may still not
	// have an absolute path here if the previous steps failed.
	if runtime.GOOS == "windows" && filepath.IsAbs(cleaned) && !strings.HasPrefix(f.RawPath, `\\`) {
		return `\\?\` + cleaned
	}

	return cleaned
}

func (s *apiSvc) getSystemStatus(w http.ResponseWriter, r *http.Request) {
	var m runtime.MemStats
	runtime.ReadMemStats(&m)

	tilde, _ := osutil.ExpandTilde("~")
	res := make(map[string]interface{})
	res["myID"] = myID.String()
	res["goroutines"] = runtime.NumGoroutine()
	res["alloc"] = m.Alloc
	res["sys"] = m.Sys - m.HeapReleased
	res["tilde"] = tilde
	if cfg.Options().GlobalAnnEnabled && s.discoverer != nil {
		res["extAnnounceOK"] = s.discoverer.ExtAnnounceOK()
	}
	if relaySvc != nil {
		res["relayClientStatus"] = relaySvc.ClientStatus()
	}
	cpuUsageLock.RLock()
	var cpusum float64
	for _, p := range cpuUsagePercent {
		cpusum += p
	}
	cpuUsageLock.RUnlock()
	res["cpuPercent"] = cpusum / float64(len(cpuUsagePercent)) / float64(runtime.NumCPU())
	res["pathSeparator"] = string(filepath.Separator)
	res["uptime"] = int(time.Since(startTime).Seconds())
	res["startTime"] = startTime

	w.Header().Set("Content-Type", "application/json; charset=utf-8")
	json.NewEncoder(w).Encode(res)
}

// homeDir returns the user's home directory, or dies trying.
func homeDir() string {
	home, err := osutil.ExpandTilde("~")
	if err != nil {
		l.Fatalln(err)
	}
	return home
}

// expandLocations replaces the variables in the location map with actual
// directory locations.
func expandLocations() error {
	for key, dir := range locations {
		for varName, value := range baseDirs {
			dir = strings.Replace(dir, "${"+varName+"}", value, -1)
		}
		var err error
		dir, err = osutil.ExpandTilde(dir)
		if err != nil {
			return err
		}
		locations[key] = dir
	}
	return nil
}

func (s *apiService) getSystemStatus(w http.ResponseWriter, r *http.Request) {
	var m runtime.MemStats
	runtime.ReadMemStats(&m)

	tilde, _ := osutil.ExpandTilde("~")
	res := make(map[string]interface{})
	res["myID"] = myID.String()
	res["goroutines"] = runtime.NumGoroutine()
	res["alloc"] = m.Alloc
	res["sys"] = m.Sys - m.HeapReleased
	res["tilde"] = tilde
	if s.cfg.Options().LocalAnnEnabled || s.cfg.Options().GlobalAnnEnabled {
		res["discoveryEnabled"] = true
		discoErrors := make(map[string]string)
		discoMethods := 0
		for disco, err := range s.discoverer.ChildErrors() {
			discoMethods++
			if err != nil {
				discoErrors[disco] = err.Error()
			}
		}
		res["discoveryMethods"] = discoMethods
		res["discoveryErrors"] = discoErrors
	}
	if s.relayService != nil {
		res["relaysEnabled"] = true
		relayClientStatus := make(map[string]bool)
		relayClientLatency := make(map[string]int)
		for _, relay := range s.relayService.Relays() {
			latency, ok := s.relayService.RelayStatus(relay)
			relayClientStatus[relay] = ok
			relayClientLatency[relay] = int(latency / time.Millisecond)
		}
		res["relayClientStatus"] = relayClientStatus
		res["relayClientLatency"] = relayClientLatency
	}
	cpuUsageLock.RLock()
	var cpusum float64
	for _, p := range cpuUsagePercent {
		cpusum += p
	}
	cpuUsageLock.RUnlock()
	res["cpuPercent"] = cpusum / float64(len(cpuUsagePercent)) / float64(runtime.NumCPU())
	res["pathSeparator"] = string(filepath.Separator)
	res["uptime"] = int(time.Since(startTime).Seconds())
	res["startTime"] = startTime
	res["themes"] = s.themes

	sendJSON(w, res)
}

func generate(generateDir string) {
	dir, err := osutil.ExpandTilde(generateDir)
	if err != nil {
		l.Fatalln("generate:", err)
	}

	info, err := os.Stat(dir)
	if err == nil && !info.IsDir() {
		l.Fatalln(dir, "is not a directory")
	}
	if err != nil && os.IsNotExist(err) {
		err = osutil.MkdirAll(dir, 0700)
		if err != nil {
			l.Fatalln("generate:", err)
		}
	}

	certFile, keyFile := filepath.Join(dir, "cert.pem"), filepath.Join(dir, "key.pem")
	cert, err := tls.LoadX509KeyPair(certFile, keyFile)
	if err == nil {
		l.Warnln("Key exists; will not overwrite.")
		l.Infoln("Device ID:", protocol.NewDeviceID(cert.Certificate[0]))
	} else {
		cert, err = tlsutil.NewCertificate(certFile, keyFile, tlsDefaultCommonName, bepRSABits)
		if err != nil {
			l.Fatalln("Create certificate:", err)
		}
		myID = protocol.NewDeviceID(cert.Certificate[0])
		if err != nil {
			l.Fatalln("Load certificate:", err)
		}
		if err == nil {
			l.Infoln("Device ID:", protocol.NewDeviceID(cert.Certificate[0]))
		}
	}

	cfgFile := filepath.Join(dir, "config.xml")
	if _, err := os.Stat(cfgFile); err == nil {
		l.Warnln("Config exists; will not overwrite.")
		return
	}
	var myName, _ = os.Hostname()
	var newCfg = defaultConfig(myName)
	var cfg = config.Wrap(cfgFile, newCfg)
	err = cfg.Save()
	if err != nil {
		l.Warnln("Failed to save config", err)
	}
}

// defaultConfigDir returns the default configuration directory, as figured
// out by various the environment variables present on each platform, or dies
// trying.
func defaultConfigDir() string {
	switch runtime.GOOS {
	case "darwin":
		dir, err := osutil.ExpandTilde("~/Library/Application Support/SyncthingFUSE")
		if err != nil {
			l.Fatalln(err)
		}
		return dir
	case "linux":
		if xdgCfg := os.Getenv("XDG_CONFIG_HOME"); xdgCfg != "" {
			return filepath.Join(xdgCfg, "syncthing")
		}
		dir, err := osutil.ExpandTilde("~/.config/syncthingfuse")
		if err != nil {
			l.Fatalln(err)
		}
		return dir

	default:
		l.Fatalln("Only OS X and Linux supported right now!")
	}

	return "nil"
}

func (s *apiService) getSystemBrowse(w http.ResponseWriter, r *http.Request) {
	qs := r.URL.Query()
	current := qs.Get("current")
	search, _ := osutil.ExpandTilde(current)
	pathSeparator := string(os.PathSeparator)
	if strings.HasSuffix(current, pathSeparator) && !strings.HasSuffix(search, pathSeparator) {
		search = search + pathSeparator
	}
	subdirectories, _ := osutil.Glob(search + "*")
	ret := make([]string, 0, 10)
	for _, subdirectory := range subdirectories {
		info, err := os.Stat(subdirectory)
		if err == nil && info.IsDir() {
			ret = append(ret, subdirectory+pathSeparator)
			if len(ret) > 9 {
				break
			}
		}
	}

	sendJSON(w, ret)
}

func (s *apiSvc) getSystemBrowse(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/json; charset=utf-8")
	qs := r.URL.Query()
	current := qs.Get("current")
	search, _ := osutil.ExpandTilde(current)
	pathSeparator := string(os.PathSeparator)
	if strings.HasSuffix(current, pathSeparator) && !strings.HasSuffix(search, pathSeparator) {
		search = search + pathSeparator
	}
	subdirectories, _ := osutil.Glob(search + "*")
	ret := make([]string, 0, 10)
	for _, subdirectory := range subdirectories {
		info, err := os.Stat(subdirectory)
		if err == nil && info.IsDir() {
			ret = append(ret, subdirectory+pathSeparator)
			if len(ret) > 9 {
				break
			}
		}
	}
	json.NewEncoder(w).Encode(ret)
}

func (f *FolderConfiguration) cleanedPath() string {
	if f.RawPath == "" {
		return ""
	}

	cleaned := f.RawPath

	// Attempt tilde expansion; leave unchanged in case of error
	if path, err := osutil.ExpandTilde(cleaned); err == nil {
		cleaned = path
	}

	// Attempt absolutification; leave unchanged in case of error
	if !filepath.IsAbs(cleaned) {
		// Abs() looks like a fairly expensive syscall on Windows, while
		// IsAbs() is a whole bunch of string mangling. I think IsAbs() may be
		// somewhat faster in the general case, hence the outer if...
		if path, err := filepath.Abs(cleaned); err == nil {
			cleaned = path
		}
	}

	// Attempt to enable long filename support on Windows. We may still not
	// have an absolute path here if the previous steps failed.
	if runtime.GOOS == "windows" && filepath.IsAbs(cleaned) && !strings.HasPrefix(f.RawPath, `\\`) {
		return `\\?\` + cleaned
	}

	// If we're not on Windows, we want the path to end with a slash to
	// penetrate symlinks. On Windows, paths must not end with a slash.
	if runtime.GOOS != "windows" && cleaned[len(cleaned)-1] != filepath.Separator {
		cleaned = cleaned + string(filepath.Separator)
	}

	return cleaned
}

func main() {
	if runtime.GOOS == "windows" {
		// On Windows, we use a log file by default. Setting the -logfile flag
		// to "-" disables this behavior.
		flag.StringVar(&logFile, "logfile", "", "Log file name (use \"-\" for stdout)")

		// We also add an option to hide the console window
		flag.BoolVar(&noConsole, "no-console", false, "Hide console window")
	} else {
		flag.StringVar(&logFile, "logfile", "-", "Log file name (use \"-\" for stdout)")
	}

	flag.StringVar(&generateDir, "generate", "", "Generate key and config in specified dir, then exit")
	flag.StringVar(&guiAddress, "gui-address", guiAddress, "Override GUI address")
	flag.StringVar(&guiAPIKey, "gui-apikey", guiAPIKey, "Override GUI API key")
	flag.StringVar(&confDir, "home", "", "Set configuration directory")
	flag.IntVar(&logFlags, "logflags", logFlags, "Select information in log line prefix")
	flag.BoolVar(&noBrowser, "no-browser", false, "Do not start browser")
	flag.BoolVar(&noRestart, "no-restart", noRestart, "Do not restart; just exit")
	flag.BoolVar(&reset, "reset", false, "Reset the database")
	flag.BoolVar(&doUpgrade, "upgrade", false, "Perform upgrade")
	flag.BoolVar(&doUpgradeCheck, "upgrade-check", false, "Check for available upgrade")
	flag.BoolVar(&showVersion, "version", false, "Show version")
	flag.StringVar(&upgradeTo, "upgrade-to", upgradeTo, "Force upgrade directly from specified URL")
	flag.BoolVar(&auditEnabled, "audit", false, "Write events to audit file")
	flag.BoolVar(&verbose, "verbose", false, "Print verbose log output")
	flag.BoolVar(&paused, "paused", false, "Start with all devices paused")

	longUsage := fmt.Sprintf(extraUsage, baseDirs["config"], debugFacilities())
	flag.Usage = usageFor(flag.CommandLine, usage, longUsage)
	flag.Parse()

	if noConsole {
		osutil.HideConsole()
	}

	if confDir != "" {
		// Not set as default above because the string can be really long.
		baseDirs["config"] = confDir
	}

	if err := expandLocations(); err != nil {
		l.Fatalln(err)
	}

	if guiAssets == "" {
		guiAssets = locations[locGUIAssets]
	}

	if logFile == "" {
		// Use the default log file location
		logFile = locations[locLogFile]
	}

	if showVersion {
		fmt.Println(LongVersion)
		return
	}

	l.SetFlags(logFlags)

	if generateDir != "" {
		dir, err := osutil.ExpandTilde(generateDir)
		if err != nil {
			l.Fatalln("generate:", err)
		}

		info, err := os.Stat(dir)
		if err == nil && !info.IsDir() {
			l.Fatalln(dir, "is not a directory")
		}
		if err != nil && os.IsNotExist(err) {
			err = osutil.MkdirAll(dir, 0700)
			if err != nil {
				l.Fatalln("generate:", err)
			}
		}

		certFile, keyFile := filepath.Join(dir, "cert.pem"), filepath.Join(dir, "key.pem")
		cert, err := tls.LoadX509KeyPair(certFile, keyFile)
		if err == nil {
			l.Warnln("Key exists; will not overwrite.")
			l.Infoln("Device ID:", protocol.NewDeviceID(cert.Certificate[0]))
		} else {
			cert, err = tlsutil.NewCertificate(certFile, keyFile, tlsDefaultCommonName, tlsRSABits)
			if err != nil {
				l.Fatalln("Create certificate:", err)
			}
			myID = protocol.NewDeviceID(cert.Certificate[0])
			if err != nil {
				l.Fatalln("Load certificate:", err)
			}
			if err == nil {
				l.Infoln("Device ID:", protocol.NewDeviceID(cert.Certificate[0]))
			}
		}

		cfgFile := filepath.Join(dir, "config.xml")
		if _, err := os.Stat(cfgFile); err == nil {
			l.Warnln("Config exists; will not overwrite.")
//.........这里部分代码省略.........