Check for unused files in output folder

CHDataManagement/Storage/SecurityBookmark.swift

@@ -388,6 +388,36 @@ struct SecurityBookmark {
         return operation(url)
     }
 
+    func getAllFiles() -> Set<String> {
+        guard url.startAccessingSecurityScopedResource() else {
+            reportError("Failed to start security scope")
+            return []
+        }
+        guard let enumerator = FileManager.default.enumerator(at: url, includingPropertiesForKeys: nil, options: [.skipsHiddenFiles]) else {
+            reportError("Failed to get folder enumerator")
+            return []
+        }
+
+        var relativePaths = Set<String>()
+        let prefix = url.path().withTrailingSlash
+
+        for case let fileURL as URL in enumerator {
+            guard !fileURL.hasDirectoryPath else {
+                continue
+            }
+            let fullPath = fileURL.path()
+            guard fullPath.hasPrefix(prefix) else {
+                print("Expected prefix \(prefix) for \(fullPath)")
+                return []
+            }
+            let relativePath = fullPath.replacingOccurrences(of: prefix, with: "")
+            relativePaths.insert(relativePath)
+        }
+
+        url.stopAccessingSecurityScopedResource()
+        return relativePaths
+    }
+
     // MARK: Unscoped helpers
 
     private func create(folder: URL) -> Bool {