[fbsync] cleanup download utils (#8273)

Reviewed By: vmoens

Differential Revision: D55062790

fbshipit-source-id: d85114aa859d025a467642ee53197ff1d88b1d1d

Author: NicolasHug

torchvision/datasets/utils.py

@@ -12,7 +12,7 @@
 import urllib.error
 import urllib.request
 import zipfile
-from typing import Any, Callable, Dict, IO, Iterable, Iterator, List, Optional, Tuple, TypeVar, Union
+from typing import Any, Callable, Dict, IO, Iterable, List, Optional, Tuple, TypeVar, Union
 from urllib.parse import urlparse
 
 import numpy as np
@@ -24,24 +24,12 @@
 USER_AGENT = "pytorch/vision"
 
 
-def _save_response_content(
-    content: Iterator[bytes],
-    destination: Union[str, pathlib.Path],
-    length: Optional[int] = None,
-) -> None:
-    with open(destination, "wb") as fh, tqdm(total=length) as pbar:
-        for chunk in content:
-            # filter out keep-alive new chunks
-            if not chunk:
-                continue
-
-            fh.write(chunk)
-            pbar.update(len(chunk))
-
-
 def _urlretrieve(url: str, filename: Union[str, pathlib.Path], chunk_size: int = 1024 * 32) -> None:
     with urllib.request.urlopen(urllib.request.Request(url, headers={"User-Agent": USER_AGENT})) as response:
-        _save_response_content(iter(lambda: response.read(chunk_size), b""), filename, length=response.length)
+        with open(filename, "wb") as fh, tqdm(total=response.length) as pbar:
+            while chunk := response.read(chunk_size):
+                fh.write(chunk)
+                pbar.update(len(chunk))
 
 
 def calculate_md5(fpath: Union[str, pathlib.Path], chunk_size: int = 1024 * 1024) -> str: