[Python-checkins] cpython: Issue #23688: Added support of arbitrary bytes-like objects and avoided

Mon Mar 23 14:28:03 CET 2015

https://hg.python.org/cpython/rev/4dc69e5124f8
changeset: 95140:4dc69e5124f8
user: Serhiy Storchaka <storchaka at gmail.com>
date: Mon Mar 23 14:59:48 2015 +0200
summary:
 Issue #23688: Added support of arbitrary bytes-like objects and avoided
unnecessary copying of memoryview in gzip.GzipFile.write().
Original patch by Wolfgang Maier.
files:
 Doc/library/gzip.rst | 4 +++
 Lib/gzip.py | 19 +++++++++------
 Lib/test/test_gzip.py | 37 +++++++++++++++++++++++++++++++
 Misc/NEWS | 4 +++
 4 files changed, 56 insertions(+), 8 deletions(-)

diff --git a/Doc/library/gzip.rst b/Doc/library/gzip.rst
--- a/Doc/library/gzip.rst
+++ b/Doc/library/gzip.rst
@@ -137,6 +137,10 @@
 .. versionchanged:: 3.4
 Added support for the ``'x'`` and ``'xb'`` modes.
 
+ .. versionchanged:: 3.5
+ Added support for writing arbitrary
+ :term:`bytes-like objects <bytes-like object>`.
+
 
 .. function:: compress(data, compresslevel=9)
 
diff --git a/Lib/gzip.py b/Lib/gzip.py
--- a/Lib/gzip.py
+++ b/Lib/gzip.py
@@ -334,17 +334,20 @@
 if self.fileobj is None:
 raise ValueError("write() on closed GzipFile object")
 
- # Convert data type if called by io.BufferedWriter.
- if isinstance(data, memoryview):
- data = data.tobytes()
+ if isinstance(data, bytes):
+ length = len(data)
+ else:
+ # accept any data that supports the buffer protocol
+ data = memoryview(data)
+ length = data.nbytes
 
- if len(data) > 0:
- self.size = self.size + len(data)
+ if length > 0:
+ self.fileobj.write(self.compress.compress(data))
+ self.size += length
 self.crc = zlib.crc32(data, self.crc) & 0xffffffff
- self.fileobj.write( self.compress.compress(data) )
- self.offset += len(data)
+ self.offset += length
 
- return len(data)
+ return length
 
 def read(self, size=-1):
 self._check_closed()
diff --git a/Lib/test/test_gzip.py b/Lib/test/test_gzip.py
--- a/Lib/test/test_gzip.py
+++ b/Lib/test/test_gzip.py
@@ -6,6 +6,7 @@
 import os
 import io
 import struct
+import array
 gzip = support.import_module('gzip')
 
 data1 = b""" int length=DEFAULTALLOC, err = Z_OK;
@@ -43,6 +44,14 @@
 
 
 class TestGzip(BaseTest):
+ def write_and_read_back(self, data, mode='b'):
+ b_data = bytes(data)
+ with gzip.GzipFile(self.filename, 'w'+mode) as f:
+ l = f.write(data)
+ self.assertEqual(l, len(b_data))
+ with gzip.GzipFile(self.filename, 'r'+mode) as f:
+ self.assertEqual(f.read(), b_data)
+
 def test_write(self):
 with gzip.GzipFile(self.filename, 'wb') as f:
 f.write(data1 * 50)
@@ -57,6 +66,34 @@
 # Test multiple close() calls.
 f.close()
 
+ # The following test_write_xy methods test that write accepts
+ # the corresponding bytes-like object type as input
+ # and that the data written equals bytes(xy) in all cases.
+ def test_write_memoryview(self):
+ self.write_and_read_back(memoryview(data1 * 50))
+ m = memoryview(bytes(range(256)))
+ data = m.cast('B', shape=[8,8,4])
+ self.write_and_read_back(data)
+
+ def test_write_bytearray(self):
+ self.write_and_read_back(bytearray(data1 * 50))
+
+ def test_write_array(self):
+ self.write_and_read_back(array.array('I', data1 * 40))
+
+ def test_write_incompatible_type(self):
+ # Test that non-bytes-like types raise TypeError.
+ # Issue #21560: attempts to write incompatible types
+ # should not affect the state of the fileobject
+ with gzip.GzipFile(self.filename, 'wb') as f:
+ with self.assertRaises(TypeError):
+ f.write('')
+ with self.assertRaises(TypeError):
+ f.write([])
+ f.write(data1)
+ with gzip.GzipFile(self.filename, 'rb') as f:
+ self.assertEqual(f.read(), data1)
+
 def test_read(self):
 self.test_write()
 # Try reading.
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -23,6 +23,10 @@
 Library
 -------
 
+- Issue #23688: Added support of arbitrary bytes-like objects and avoided
+ unnecessary copying of memoryview in gzip.GzipFile.write().
+ Original patch by Wolfgang Maier.
+
 - Issue #23252: Added support for writing ZIP files to unseekable streams.
 
 - Issue #21526: Tkinter now supports new boolean type in Tcl 8.5.
-- 
Repository URL: https://hg.python.org/cpython
