From 876dda83f2ff9f4dddf06733d5d14d38ab8f320a Mon Sep 17 00:00:00 2001
From: Deluan <deluan@navidrome.org>
Date: Wed, 21 Jul 2021 22:17:37 -0400
Subject: [PATCH] Reduce number of calls to `lstat`.

Should make the scanner a bit faster, specially in networked filesystems
---
 scanner/tag_scanner.go | 44 ++++++++++++++++++++----------------------
 1 file changed, 21 insertions(+), 23 deletions(-)

diff --git a/scanner/tag_scanner.go b/scanner/tag_scanner.go
index 2f8dabeff..598a132b4 100644
--- a/scanner/tag_scanner.go
+++ b/scanner/tag_scanner.go
@@ -2,6 +2,7 @@ package scanner
 
 import (
 	"context"
+	"io/fs"
 	"os"
 	"path/filepath"
 	"sort"
@@ -249,7 +250,7 @@ func (s *TagScanner) processChangedDir(ctx context.Context, dir string, fullScan
 		currentTracks[t.Path] = t
 	}
 
-	// Load tracks FileInfo from the folder
+	// Load track list from the folder
 	files, err := loadAllAudioFiles(dir)
 	if err != nil {
 		return err
@@ -268,15 +269,21 @@ func (s *TagScanner) processChangedDir(ctx context.Context, dir string, fullScan
 	// If track from folder is newer than the one in DB, select for update/insert in DB
 	log.Trace(ctx, "Processing changed folder", "dir", dir, "tracksInDB", len(currentTracks), "tracksInFolder", len(files))
 	var filesToUpdate []string
-	for filePath, info := range files {
-		c, ok := currentTracks[filePath]
-		if !ok {
+	for filePath, entry := range files {
+		c, inDB := currentTracks[filePath]
+		if !inDB || fullScan {
 			filesToUpdate = append(filesToUpdate, filePath)
 			s.cnt.added++
-		}
-		if ok && (info.ModTime().After(c.UpdatedAt) || fullScan) {
-			filesToUpdate = append(filesToUpdate, filePath)
-			s.cnt.updated++
+		} else {
+			info, err := entry.Info()
+			if err != nil {
+				log.Error("Could not stat file", "filePath", filePath, err)
+				continue
+			}
+			if info.ModTime().After(c.UpdatedAt) {
+				filesToUpdate = append(filesToUpdate, filePath)
+				s.cnt.updated++
+			}
 		}
 
 		// Force a refresh of the album and artist, to cater for cover art files
@@ -311,7 +318,7 @@ func (s *TagScanner) processChangedDir(ctx context.Context, dir string, fullScan
 
 	err = buffer.flush()
 	log.Info(ctx, "Finished processing changed folder", "dir", dir, "updated", numUpdatedTracks,
-		"purged", numPurgedTracks, "elapsed", time.Since(start))
+		"deleted", numPurgedTracks, "elapsed", time.Since(start))
 	return err
 }
 
@@ -393,16 +400,12 @@ func (s *TagScanner) withAdminUser(ctx context.Context) context.Context {
 	return request.WithUser(ctx, *u)
 }
 
-func loadAllAudioFiles(dirPath string) (map[string]os.FileInfo, error) {
-	dir, err := os.Open(dirPath)
+func loadAllAudioFiles(dirPath string) (map[string]fs.DirEntry, error) {
+	files, err := fs.ReadDir(os.DirFS(dirPath), ".")
 	if err != nil {
 		return nil, err
 	}
-	files, err := dir.Readdir(-1)
-	if err != nil {
-		return nil, err
-	}
-	audioFiles := make(map[string]os.FileInfo)
+	fileInfos := make(map[string]fs.DirEntry)
 	for _, f := range files {
 		if f.IsDir() {
 			continue
@@ -414,13 +417,8 @@ func loadAllAudioFiles(dirPath string) (map[string]os.FileInfo, error) {
 		if !utils.IsAudioFile(filePath) {
 			continue
 		}
-		fi, err := os.Stat(filePath)
-		if err != nil {
-			log.Error("Could not stat file", "filePath", filePath, err)
-		} else {
-			audioFiles[filePath] = fi
-		}
+		fileInfos[filePath] = f
 	}
 
-	return audioFiles, nil
+	return fileInfos, nil
 }