Make background image check way more efficient

cmd/backend/images.go

@@ -17,6 +17,53 @@ import (
 
 var ErrUnsupportedFormat error = image.ErrFormat // used internally by imaging
 
+func checkImageUsage(c *Config, db *DB, name string) (bool, error) {
+	imageWasFound := false
+
+	if err := filepath.Walk(c.ArticleDir, func(path string, info fs.FileInfo, err error) error {
+		if err != nil {
+			return fmt.Errorf("error walking articles filepath: %v", err)
+		}
+
+		if !info.IsDir() {
+			mdFile, err := os.Open(path)
+			if err != nil {
+				return fmt.Errorf("error opening article %v: %v", info.Name(), err)
+			}
+			defer mdFile.Close()
+
+			scanner := bufio.NewScanner(mdFile)
+			for scanner.Scan() {
+				if strings.Contains(scanner.Text(), name) {
+					imageWasFound = true
+					return nil
+				}
+			}
+
+			return scanner.Err()
+		}
+
+		return nil
+	}); err != nil {
+		return false, fmt.Errorf("error walking articles filepath: %v", err)
+	}
+
+	if !imageWasFound {
+		users, err := db.GetAllUsers(c)
+		if err != nil {
+			return false, fmt.Errorf("error getting all users: %v", err)
+		}
+
+		for _, user := range users {
+			if name == user.ProfilePicLink {
+				return true, nil
+			}
+		}
+	}
+
+	return imageWasFound, nil
+}
+
 func SaveImage(src io.Reader, maxHeight, maxWidth int, path string) (string, error) {
 	img, err := imaging.Decode(src, imaging.AutoOrientation(true))
 	if err != nil {
@@ -56,45 +103,10 @@ func CleanUpImages(c *Config, db *DB) error {
 		if !info.IsDir() {
 			imageName := info.Name()
 			imagePath := path
-			imageWasFound := false
 
-			if err = filepath.Walk(c.ArticleDir, func(path string, info fs.FileInfo, err error) error {
+			imageWasFound, err := checkImageUsage(c, db, imageName)
 			if err != nil {
-					return fmt.Errorf("error walking articles filepath: %v", err)
+				return fmt.Errorf("error checking image usage: %v", err)
-				}
-
-				if !info.IsDir() {
-					mdFile, err := os.Open(path)
-					if err != nil {
-						return fmt.Errorf("error opening article %v: %v", info.Name(), err)
-					}
-					defer mdFile.Close()
-
-					scanner := bufio.NewScanner(mdFile)
-
-					for scanner.Scan() {
-						if strings.Contains(scanner.Text(), imageName) {
-							imageWasFound = true
-						}
-					}
-
-					return scanner.Err()
-				}
-
-				return nil
-			}); err != nil {
-				return fmt.Errorf("error walking articles filepath: %v", err)
-			}
-
-			users, err := db.GetAllUsers(c)
-			if err != nil {
-				return fmt.Errorf("error getting all users: %v", err)
-			}
-
-			for _, user := range users {
-				if imageName == user.ProfilePicLink {
-					imageWasFound = true
-				}
 			}
 
 			if !imageWasFound {