use constant for write buffer size

python · gpshead · May 8, 2023 · Jan 22, 2023 · Jan 22, 2023 · Jan 22, 2023
commit fe31588314f11c40d5a9de54bd15ec746898bf6e
diff --git a/Lib/gzip.py b/Lib/gzip.py
@@ -22,12 +22,11 @@
 _COMPRESS_LEVEL_BEST = 9

 READ_BUFFER_SIZE = 128 * 1024
-DEFAULT_WRITE_BUFFER_SIZE = 4 * io.DEFAULT_BUFFER_SIZE
+_WRITE_BUFFER_SIZE = 4 * io.DEFAULT_BUFFER_SIZE


 def open(filename, mode="rb", compresslevel=_COMPRESS_LEVEL_BEST,
-         encoding=None, errors=None, newline=None,
-         buffer_size=DEFAULT_WRITE_BUFFER_SIZE):
+         encoding=None, errors=None, newline=None):
    """Open a gzip-compressed file in binary or text mode.

    The filename argument can be an actual filename (a str or bytes object), or
@@ -59,9 +58,9 @@ def open(filename, mode="rb", compresslevel=_COMPRESS_LEVEL_BEST,

    gz_mode = mode.replace("t", "")
    if isinstance(filename, (str, bytes, os.PathLike)):
-        binary_file = GzipFile(filename, gz_mode, compresslevel, buffer_size=buffer_size)
+        binary_file = GzipFile(filename, gz_mode, compresslevel)
    elif hasattr(filename, "read") or hasattr(filename, "write"):
-        binary_file = GzipFile(None, gz_mode, compresslevel, filename, buffer_size=buffer_size)
+        binary_file = GzipFile(None, gz_mode, compresslevel, filename)
    else:
        raise TypeError("filename must be a str or bytes object, or a file")

@@ -151,8 +150,7 @@ class GzipFile(_compression.BaseStream):
    myfileobj = None

    def __init__(self, filename=None, mode=None,
-                 compresslevel=_COMPRESS_LEVEL_BEST, fileobj=None, mtime=None,
-                 buffer_size=DEFAULT_WRITE_BUFFER_SIZE):
+                 compresslevel=_COMPRESS_LEVEL_BEST, fileobj=None, mtime=None):
        """Constructor for the GzipFile class.

        At least one of fileobj and filename must be given a
@@ -202,7 +200,6 @@ def __init__(self, filename=None, mode=None,
        if mode is None:
            mode = getattr(fileobj, 'mode', 'rb')

-        self.buffer_size = buffer_size

        if mode.startswith('r'):
            self.mode = READ
@@ -226,8 +223,9 @@ def __init__(self, filename=None, mode=None,
                                             zlib.DEF_MEM_LEVEL,
                                             0)
            self._write_mtime = mtime
+            self._buffer_size = _WRITE_BUFFER_SIZE
            self._buffer = io.BufferedWriter(_WriteBufferStream(self),
-                                             buffer_size=buffer_size)
+                                             buffer_size=self._buffer_size)
        else:
            raise ValueError("Invalid mode: {!r}".format(mode))

@@ -410,10 +408,10 @@ def seek(self, offset, whence=io.SEEK_SET):
            if offset < self.offset:
                raise OSError('Negative seek in write mode')
            count = offset - self.offset
-            chunk = b'\0' * self.buffer_size
-            for i in range(count // self.buffer_size):
+            chunk = b'\0' * self._buffer_size
+            for i in range(count // self._buffer_size):
                self.write(chunk)
-            self.write(b'\0' * (count % self.buffer_size))
+            self.write(b'\0' * (count % self._buffer_size))
        elif self.mode == READ:
            self._check_not_closed()
            return self._buffer.seek(offset, whence)