Simpler file chunking (#7673)

Co-authored-by: Philip Meier <github.pmeier@posteo.de>

packaging/wheel/relocate.py

@@ -2,7 +2,6 @@
 
 import glob
 import hashlib
-import io
 
 # Standard library imports
 import os
@@ -65,21 +64,12 @@ PLATFORM_ARCH = platform.machine()
 PYTHON_VERSION = sys.version_info
 
 
-def read_chunks(file, size=io.DEFAULT_BUFFER_SIZE):
-    """Yield pieces of data from a file-like object until EOF."""
-    while True:
-        chunk = file.read(size)
-        if not chunk:
-            break
-        yield chunk
-
-
 def rehash(path, blocksize=1 << 20):
     """Return (hash, length) for path using hashlib.sha256()"""
     h = hashlib.sha256()
     length = 0
     with open(path, "rb") as f:
-        for block in read_chunks(f, size=blocksize):
+        while block := f.read(blocksize):
             length += len(block)
             h.update(block)
     digest = "sha256=" + urlsafe_b64encode(h.digest()).decode("latin1").rstrip("=")

torchvision/datasets/utils.py

@@ -57,7 +57,7 @@ def calculate_md5(fpath: str, chunk_size: int = 1024 * 1024) -> str:
     else:
         md5 = hashlib.md5()
     with open(fpath, "rb") as f:
-        for chunk in iter(lambda: f.read(chunk_size), b""):
+        while chunk := f.read(chunk_size):
             md5.update(chunk)
     return md5.hexdigest()
 

torchvision/prototype/datasets/_builtin/README.md

@@ -91,7 +91,7 @@ import hashlib
 def sha256sum(path, chunk_size=1024 * 1024):
     checksum = hashlib.sha256()
     with open(path, "rb") as f:
-        for chunk in iter(lambda: f.read(chunk_size), b""):
+        while chunk := f.read(chunk_size):
             checksum.update(chunk)
     print(checksum.hexdigest())
 ```

torchvision/prototype/datasets/utils/_resource.py

@@ -136,7 +136,7 @@ class OnlineResource(abc.ABC):
     def _check_sha256(self, path: pathlib.Path, *, chunk_size: int = 1024 * 1024) -> None:
         hash = hashlib.sha256()
         with open(path, "rb") as file:
-            for chunk in iter(lambda: file.read(chunk_size), b""):
+            while chunk := file.read(chunk_size):
                 hash.update(chunk)
         sha256 = hash.hexdigest()
         if sha256 != self.sha256: