implemented FileIndex class

src/jarklin/common/fileindex.py

@@ -0,0 +1,49 @@
+# -*- coding=utf-8 -*-
+r"""
+
+"""
+import typing as t
+from os import PathLike
+from pathlib import Path
+
+
+__all__ = ['FileIndex']
+
+
+class FileIndex:
+    fp: Path
+    root: Path = None
+    _index: t.List[Path]
+
+    def __init__(self, fp: PathLike):
+        self.fp = Path(fp)
+        self.root = self.fp.parent
+        self._index = []
+
+    def load(self) -> None:
+        r""" loads the index from disk """
+        with open(self.fp, "r") as f:
+            self._index.clear()
+            for line in f:
+                line = line.strip()
+                if not line or line.startswith("#"): continue
+                self._index.append(self.root / line)
+
+    def save(self) -> None:
+        r""" saves the index to disk """
+        with open(self.fp, "w") as f:
+            for fp in self._index:
+                f.write(f"{fp.relative_to(self.root)!s}")
+
+    def add_file(self, file: PathLike):
+        r""" add a file to the index (memory only) """
+        self._index.append(self.root / file)
+
+    def unlink(self, missing_ok: bool=False) -> None:
+        r""" unlinks the file-index itself """
+        self.fp.unlink(missing_ok=missing_ok)
+
+    def unlink_indexed(self) -> None:
+        r""" unlinks all indexed files """
+        for fp in self._index:
+            fp.unlink(missing_ok=True)