fix: avoid superfluous calls to os.walk when relinking missing files (#610)

Author: Toby222

tagstudio/src/core/library/json/library.py

@@ -304,6 +304,8 @@ class Library:
     def __init__(self) -> None:
         # Library Info =========================================================
         self.library_dir: Path = None
+        # Cached result of os.walk when relinking library files
+        self._library_file_cache: list[(string, list[string], list[string])] = None
 
         # Entries ==============================================================
         # List of every Entry object.
@@ -1092,6 +1094,7 @@ def fix_missing_files(self):
                     yield (i, True)
                 else:
                     yield (i, False)
+        self._library_file_cache = None
 
         # self._purge_empty_missing_entries()
 
@@ -1124,9 +1127,12 @@ def _match_missing_file(self, file: str) -> list[Path]:
 
         matches = []
 
+        if self._library_file_cache is None:
+            self._library_file_cache = list(os.walk(self.library_dir))
+
         # for file in self.missing_files:
         path = Path(file)
-        for root, dirs, files in os.walk(self.library_dir):
+        for root, dirs, files in self._library_file_cache:
             for f in files:
                 # print(f'{tail} --- {f}')
                 if path.name == f and "$recycle.bin" not in str(root).lower():