Remove mirror_*_download functions

mirror_target_download and mirror_meta_download functions that
return iterators are causing more troubles than good.

Since there is a need to download and verify each file inside
the mirrors loop (before continuing to the next mirror), feels
like the correct component to do this is the Updater itself.
This means slightly repetitive code inside the Updater class
but with the benefit of better readability and less bug-prone
implementation.

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

Author: sechkova

tuf/client_rework/mirrors.py

@@ -23,15 +23,13 @@
 """
 
 import os
-from typing import BinaryIO, Dict, TextIO
 from urllib import parse
 
 from securesystemslib import exceptions as sslib_exceptions
 from securesystemslib import formats as sslib_formats
 from securesystemslib import util as sslib_util
 
-from tuf import exceptions, formats
-from tuf.client_rework import download
+from tuf import formats
 
 # The type of file to be downloaded from a repository.  The
 # 'get_list_of_mirrors' function supports these file types.
@@ -130,67 +128,3 @@ def get_list_of_mirrors(file_type, file_path, mirrors_dict):
         list_of_mirrors.append(url.replace("\\", "/"))
 
     return list_of_mirrors
-
-
-def mirror_meta_download(
-    filename: str,
-    upper_length: int,
-    mirrors_config: Dict,
-    fetcher: "FetcherInterface",
-) -> TextIO:
-    """
-    Download metadata file from the list of metadata mirrors
-    """
-    file_mirrors = get_list_of_mirrors("meta", filename, mirrors_config)
-
-    file_mirror_errors = {}
-    for file_mirror in file_mirrors:
-        try:
-            temp_obj = download.download_file(
-                file_mirror, upper_length, fetcher, strict_required_length=False
-            )
-
-            temp_obj.seek(0)
-            yield temp_obj
-
-        # pylint cannot figure out that we store the exceptions
-        # in a dictionary to raise them later so we disable
-        # the warning. This should be reviewed in the future still.
-        except Exception as exception:  # pylint:  disable=broad-except
-            file_mirror_errors[file_mirror] = exception
-
-        finally:
-            if file_mirror_errors:
-                raise exceptions.NoWorkingMirrorError(file_mirror_errors)
-
-
-def mirror_target_download(
-    fileinfo: str, mirrors_config: Dict, fetcher: "FetcherInterface"
-) -> BinaryIO:
-    """
-    Download target file from the list of target mirrors
-    """
-    # full_filename = _get_full_name(filename)
-    file_mirrors = get_list_of_mirrors(
-        "target", fileinfo["filepath"], mirrors_config
-    )
-
-    file_mirror_errors = {}
-    for file_mirror in file_mirrors:
-        try:
-            temp_obj = download.download_file(
-                file_mirror, fileinfo["fileinfo"]["length"], fetcher
-            )
-
-            temp_obj.seek(0)
-            yield temp_obj
-
-        # pylint cannot figure out that we store the exceptions
-        # in a dictionary to raise them later so we disable
-        # the warning. This should be reviewed in the future still.
-        except Exception as exception:  # pylint:  disable=broad-except
-            file_mirror_errors[file_mirror] = exception
-
-        finally:
-            if file_mirror_errors:
-                raise exceptions.NoWorkingMirrorError(file_mirror_errors)