Remove unsafe_download option for target files

Remove the boolean switch to toggle safe or unsafe download
in Updater._get_file since the method is private and is always
called with the download_safely option enabled.

Signed-off-by: Teodora Sechkova <[email protected]>

Author: sechkova

tests/test_updater.py

@@ -1771,10 +1771,7 @@ def verify_target_file(targets_path):
       self.repository_updater._check_hashes(targets_path, file_hashes)
 
     self.repository_updater._get_file('targets.json', verify_target_file,
-        file_type, file_size, download_safely=True).close()
-
-    self.repository_updater._get_file('targets.json', verify_target_file,
-        file_type, file_size, download_safely=False).close()
+        file_type, file_size).close()
 
   def test_13__targets_of_role(self):
     # Test case where a list of targets is given.  By default, the 'targets'

tuf/client/updater.py

@@ -1370,7 +1370,7 @@ def verify_target_file(target_file_object):
       target_filepath = os.path.join(dirname, target_digest + '.' + basename)
 
     return self._get_file(target_filepath, verify_target_file,
-        'target', file_length, download_safely=True)
+        'target', file_length)
 
 
 
@@ -1654,8 +1654,7 @@ def _get_metadata_file(self, metadata_role, remote_filename,
 
 
 
-  def _get_file(self, filepath, verify_file_function, file_type, file_length,
-      download_safely=True):
+  def _get_file(self, filepath, verify_file_function, file_type, file_length):
     """
     <Purpose>
       Non-public method that tries downloading, up to a certain length, a
@@ -1682,9 +1681,6 @@ def _get_file(self, filepath, verify_file_function, file_type, file_length,
         The expected length, or upper bound, of the target or metadata file to
         be downloaded.
 
-      download_safely:
-        A boolean switch to toggle safe or unsafe download of the file.
-
     <Exceptions>
       tuf.exceptions.NoWorkingMirrorError:
         The metadata could not be fetched. This is raised only when all known
@@ -1708,15 +1704,9 @@ def _get_file(self, filepath, verify_file_function, file_type, file_length,
 
     for file_mirror in file_mirrors:
       try:
-        # TODO: Instead of the more fragile 'download_safely' switch, unroll
-        # the function into two separate ones: one for "safe" download, and the
-        # other one for "unsafe" download? This should induce safer and more
-        # readable code.
-        if download_safely:
-          file_object = tuf.download.safe_download(file_mirror, file_length)
-
-        else:
-          file_object = tuf.download.unsafe_download(file_mirror, file_length)
+        # Eensure the length of the downloaded file matches 'file_length'
+        # exactly.
+        file_object = tuf.download.safe_download(file_mirror, file_length)
 
         # Verify 'file_object' according to the callable function.
         # 'file_object' is also verified if decompressed above (i.e., the