X-Git-Url: https://wannabe.guru.org/gitweb/?a=blobdiff_plain;f=directory_filter.py;h=69e5547255e20ac66cfea81658867c8697501126;hb=532df2c5b57c7517dfb3dddd8c1358fbadf8baf3;hp=b076badf25dff7e34e2358b3e45d52c49692a424;hpb=5317c50ce7a96a37acfab3800c0935580766dbbf;p=python_utils.git

diff --git a/directory_filter.py b/directory_filter.py
index b076bad..69e5547 100644
--- a/directory_filter.py
+++ b/directory_filter.py
@@ -1,5 +1,15 @@
 #!/usr/bin/env python3
 
+# © Copyright 2021-2022, Scott Gasch
+
+"""Two predicates that can help avoid unnecessary disk I/O by
+detecting if a particular file is identical to the contents about to
+be written or if a particular directory already contains a file that
+is identical to the one to be written.  See class docs below for
+examples.
+
+"""
+
 import hashlib
 import logging
 import os
@@ -55,21 +65,21 @@ class DirectoryFileFilter(object):
         assert file_utils.does_file_exist(filename)
         if mtime is None:
             mtime = file_utils.get_file_raw_mtime(filename)
-        assert mtime
+        assert mtime is not None
         if self.mtime_by_filename.get(filename, 0) != mtime:
             md5 = file_utils.get_file_md5(filename)
-            logger.debug(f'Computed/stored {filename}\'s MD5 at ts={mtime} ({md5})')
+            logger.debug('Computed/stored %s\'s MD5 at ts=%.2f (%s)', filename, mtime, md5)
             self.mtime_by_filename[filename] = mtime
             self.md5_by_filename[filename] = md5
 
     def apply(self, item: Any, filename: str) -> bool:
         self._update_file(filename)
         file_md5 = self.md5_by_filename.get(filename, 0)
-        logger.debug(f'{filename}\'s checksum is {file_md5}')
+        logger.debug('%s\'s checksum is %s', filename, file_md5)
         mem_hash = hashlib.md5()
         mem_hash.update(item)
         md5 = mem_hash.hexdigest()
-        logger.debug(f'Item\'s checksum is {md5}')
+        logger.debug('Item\'s checksum is %s', md5)
         return md5 != file_md5
 
 
@@ -112,7 +122,7 @@ class DirectoryAllFilesFilter(DirectoryFileFilter):
         assert file_utils.does_file_exist(filename)
         if mtime is None:
             mtime = file_utils.get_file_raw_mtime(filename)
-        assert mtime
+        assert mtime is not None
         if self.mtime_by_filename.get(filename, 0) != mtime:
             md5 = file_utils.get_file_md5(filename)
             self.mtime_by_filename[filename] = mtime
@@ -120,7 +130,7 @@ class DirectoryAllFilesFilter(DirectoryFileFilter):
             self.all_md5s.add(md5)
 
     def apply(self, item: Any, ignored_filename: str = None) -> bool:
-        assert not ignored_filename
+        assert ignored_filename is None
         self._update()
         mem_hash = hashlib.md5()
         mem_hash.update(item)