server auth

apps/server/internal/app/watcher.go

@@ -7,15 +7,19 @@ import (
 	"os"
 	"path/filepath"
 	"strings"
+	"time"
 
 	"github.com/fsnotify/fsnotify"
 )
 
+const fileWatcherDebounce = 500 * time.Millisecond
+
 type FileWatcher struct {
 	watcher  *fsnotify.Watcher
 	rootDir  string
 	onChange func(path string)
 	logger   *slog.Logger
+	debounce time.Duration
 }
 
 func NewFileWatcher(rootDir string, logger *slog.Logger) (*FileWatcher, error) {
@@ -25,9 +29,10 @@ func NewFileWatcher(rootDir string, logger *slog.Logger) (*FileWatcher, error) {
 	}
 
 	fw := &FileWatcher{
-		watcher: watcher,
-		rootDir: rootDir,
-		logger:  logger,
+		watcher:  watcher,
+		rootDir:  rootDir,
+		logger:   logger,
+		debounce: fileWatcherDebounce,
 	}
 
 	if err := fw.addWatches(); err != nil {
@@ -39,19 +44,150 @@ func NewFileWatcher(rootDir string, logger *slog.Logger) (*FileWatcher, error) {
 }
 
 func (fw *FileWatcher) addWatches() error {
-	return filepath.Walk(fw.rootDir, func(path string, info os.FileInfo, err error) error {
+	return filepath.WalkDir(fw.rootDir, func(path string, entry os.DirEntry, err error) error {
 		if err != nil {
 			return nil
 		}
-		if info.IsDir() {
-			if err := fw.watcher.Add(path); err != nil {
-				fw.logger.Warn("watch directory", "path", path, "error", err)
-			}
+		if !entry.IsDir() {
+			return nil
+		}
+		if path != fw.rootDir && fw.shouldIgnorePath(path) {
+			return filepath.SkipDir
+		}
+		if err := fw.watcher.Add(path); err != nil {
+			fw.logger.Warn("watch directory", "path", path, "error", err)
 		}
 		return nil
 	})
 }
 
+func (fw *FileWatcher) addWatchIfDirectory(path string) {
+	if fw.shouldIgnorePath(path) {
+		return
+	}
+	info, err := os.Stat(path)
+	if err != nil || !info.IsDir() {
+		return
+	}
+	if err := fw.watcher.Add(path); err != nil {
+		fw.logger.Warn("watch new directory", "path", path, "error", err)
+	}
+}
+
+func (fw *FileWatcher) flushPending(pending map[string]struct{}) {
+	if len(pending) == 0 || fw.onChange == nil {
+		return
+	}
+
+	var changedPath string
+	for path := range pending {
+		changedPath = path
+		break
+	}
+	clear(pending)
+	fw.onChange(changedPath)
+}
+
+func (fw *FileWatcher) scheduleSync(path string, pending map[string]struct{}, timer **time.Timer, timerC *<-chan time.Time) {
+	pending[path] = struct{}{}
+
+	if *timer == nil {
+		*timer = time.NewTimer(fw.debounce)
+		*timerC = (*timer).C
+		return
+	}
+
+	if !(*timer).Stop() {
+		select {
+		case <-(*timer).C:
+		default:
+		}
+	}
+	(*timer).Reset(fw.debounce)
+}
+
+func (fw *FileWatcher) stopTimer(timer *time.Timer) {
+	if timer == nil {
+		return
+	}
+	if !timer.Stop() {
+		select {
+		case <-timer.C:
+		default:
+		}
+	}
+}
+
+func (fw *FileWatcher) isMarkdownPath(path string) bool {
+	return strings.EqualFold(filepath.Ext(path), ".md")
+}
+
+func (fw *FileWatcher) shouldIgnorePath(path string) bool {
+	rel, err := filepath.Rel(fw.rootDir, path)
+	if err != nil {
+		return true
+	}
+	if rel == "." {
+		return false
+	}
+	if rel == ".." || strings.HasPrefix(rel, ".."+string(filepath.Separator)) {
+		return true
+	}
+
+	for _, part := range strings.Split(rel, string(filepath.Separator)) {
+		if part == "" {
+			continue
+		}
+		if strings.HasPrefix(part, ".") {
+			return true
+		}
+		if isTempFileName(part) {
+			return true
+		}
+	}
+	return false
+}
+
+func isTempFileName(name string) bool {
+	if strings.HasSuffix(name, "~") {
+		return true
+	}
+	if strings.HasPrefix(name, "#") && strings.HasSuffix(name, "#") {
+		return true
+	}
+
+	switch strings.ToLower(filepath.Ext(name)) {
+	case ".swp", ".swo", ".tmp", ".temp", ".bak", ".orig", ".part", ".crdownload":
+		return true
+	}
+
+	switch name {
+	case ".DS_Store", "Thumbs.db":
+		return true
+	default:
+		return false
+	}
+}
+
+func (fw *FileWatcher) isProcessableEvent(event fsnotify.Event) bool {
+	if event.Op&(fsnotify.Write|fsnotify.Create|fsnotify.Remove|fsnotify.Rename) == 0 {
+		return false
+	}
+	if fw.shouldIgnorePath(event.Name) {
+		return false
+	}
+	return fw.isMarkdownPath(event.Name)
+}
+
+func (fw *FileWatcher) handleEvent(event fsnotify.Event, pending map[string]struct{}, timer **time.Timer, timerC *<-chan time.Time) {
+	if event.Op&(fsnotify.Create|fsnotify.Rename) != 0 {
+		fw.addWatchIfDirectory(event.Name)
+	}
+	if fw.isProcessableEvent(event) {
+		fw.scheduleSync(event.Name, pending, timer, timerC)
+	}
+}
+
 func (fw *FileWatcher) SetOnChange(fn func(path string)) {
 	fw.onChange = fn
 }
@@ -59,24 +195,24 @@ func (fw *FileWatcher) SetOnChange(fn func(path string)) {
 func (fw *FileWatcher) Run(ctx context.Context) {
 	defer fw.watcher.Close()
 
+	pending := make(map[string]struct{})
+	var timer *time.Timer
+	var timerC <-chan time.Time
+	defer fw.stopTimer(timer)
+
 	for {
 		select {
 		case <-ctx.Done():
 			return
+		case <-timerC:
+			fw.flushPending(pending)
+			timer = nil
+			timerC = nil
 		case event, ok := <-fw.watcher.Events:
 			if !ok {
 				return
 			}
-			if fw.shouldProcess(event) {
-				if event.Op&fsnotify.Create == fsnotify.Create {
-					if info, err := os.Stat(event.Name); err == nil && info.IsDir() {
-						fw.watcher.Add(event.Name)
-					}
-				}
-				if fw.onChange != nil {
-					fw.onChange(event.Name)
-				}
-			}
+			fw.handleEvent(event, pending, &timer, &timerC)
 		case err, ok := <-fw.watcher.Errors:
 			if !ok {
 				return
@@ -85,17 +221,3 @@ func (fw *FileWatcher) Run(ctx context.Context) {
 		}
 	}
 }
-
-func (fw *FileWatcher) shouldProcess(event fsnotify.Event) bool {
-	if event.Op&(fsnotify.Write|fsnotify.Create|fsnotify.Remove|fsnotify.Rename) == 0 {
-		return false
-	}
-	name := filepath.Base(event.Name)
-	if strings.HasPrefix(name, ".") || strings.HasSuffix(name, "~") {
-		return false
-	}
-	if filepath.Ext(event.Name) == ".md" || event.Op&fsnotify.Remove != 0 {
-		return true
-	}
-	return false
-}