Since this thing is on the innerwebs I suppose it should have a

[python_utils.git] / file_utils.py

diff --git a/file_utils.py b/file_utils.py
index d1e2eff1fac729b6251179ad7dfc584a0674215f..91aeea072b03d94d670a13ca1a348b407d5734b8 100644 (file)
--- a/file_utils.py
+++ b/file_utils.py
@@ -1,7 +1,10 @@
 #!/usr/bin/env python3
 
+# © Copyright 2021-2022, Scott Gasch
+
 """Utilities for working with files."""
 
+import contextlib
 import datetime
 import errno
 import glob
@@ -12,21 +15,21 @@ import pathlib
 import re
 import time
 from os.path import exists, isfile, join
-from typing import List, Optional, TextIO
+from typing import Callable, List, Literal, Optional, TextIO
 from uuid import uuid4
 
 logger = logging.getLogger(__name__)
 
 
-def remove_newlines(x):
+def remove_newlines(x: str) -> str:
     return x.replace('\n', '')
 
 
-def strip_whitespace(x):
+def strip_whitespace(x: str) -> str:
     return x.strip()
 
 
-def remove_hash_comments(x):
+def remove_hash_comments(x: str) -> str:
     return re.sub(r'#.*$', '', x)
 
 
@@ -34,15 +37,16 @@ def slurp_file(
     filename: str,
     *,
     skip_blank_lines=False,
-    line_transformers=[],
+    line_transformers: Optional[List[Callable[[str], str]]] = None,
 ):
     ret = []
     if not file_is_readable(filename):
         raise Exception(f'{filename} can\'t be read.')
     with open(filename) as rf:
         for line in rf:
-            for transformation in line_transformers:
-                line = transformation(line)
+            if line_transformers is not None:
+                for transformation in line_transformers:
+                    line = transformation(line)
             if skip_blank_lines and line == '':
                 continue
             ret.append(line)
@@ -460,7 +464,7 @@ def get_files_recursive(directory: str):
             yield file_or_directory
 
 
-class FileWriter(object):
+class FileWriter(contextlib.AbstractContextManager):
     """A helper that writes a file to a temporary location and then moves
     it atomically to its ultimate destination on close.
 
@@ -477,14 +481,14 @@ class FileWriter(object):
         self.handle = open(self.tempfile, mode="w")
         return self.handle
 
-    def __exit__(self, exc_type, exc_val, exc_tb) -> Optional[bool]:
+    def __exit__(self, exc_type, exc_val, exc_tb) -> Literal[False]:
         if self.handle is not None:
             self.handle.close()
             cmd = f'/bin/mv -f {self.tempfile} {self.filename}'
             ret = os.system(cmd)
             if (ret >> 8) != 0:
-                raise Exception(f'{cmd} failed, exit value {ret>>8}')
-        return None
+                raise Exception(f'{cmd} failed, exit value {ret>>8}!')
+        return False
 
 
 if __name__ == '__main__':