[Python-checkins] cpython: Issue #21717: tarfile.open() now supports 'x' (exclusive creation) mode.
berker.peksag
python-checkins at python.org
Fri Feb 13 20:01:54 CET 2015
https://hg.python.org/cpython/rev/ed9e9e6b3c1e
changeset: 94604:ed9e9e6b3c1e
user: Berker Peksag <berker.peksag at gmail.com>
date: Fri Feb 13 21:02:12 2015 +0200
summary:
Issue #21717: tarfile.open() now supports 'x' (exclusive creation) mode.
files:
Doc/library/tarfile.rst | 37 +++++++++--
Doc/whatsnew/3.5.rst | 6 ++
Lib/tarfile.py | 37 +++++++----
Lib/test/test_tarfile.py | 82 ++++++++++++++++++++++++++++
Misc/NEWS | 2 +
5 files changed, 142 insertions(+), 22 deletions(-)
diff --git a/Doc/library/tarfile.rst b/Doc/library/tarfile.rst
--- a/Doc/library/tarfile.rst
+++ b/Doc/library/tarfile.rst
@@ -62,6 +62,23 @@
+------------------+---------------------------------------------+
| ``'r:xz'`` | Open for reading with lzma compression. |
+------------------+---------------------------------------------+
+ | ``'x'`` or | Create a tarfile exclusively without |
+ | ``'x:'`` | compression. |
+ | | Raise an :exc:`FileExistsError` exception |
+ | | if it is already exists. |
+ +------------------+---------------------------------------------+
+ | ``'x:gz'`` | Create a tarfile with gzip compression. |
+ | | Raise an :exc:`FileExistsError` exception |
+ | | if it is already exists. |
+ +------------------+---------------------------------------------+
+ | ``'x:bz2'`` | Create a tarfile with bzip2 compression. |
+ | | Raise an :exc:`FileExistsError` exception |
+ | | if it is already exists. |
+ +------------------+---------------------------------------------+
+ | ``'x:xz'`` | Create a tarfile with lzma compression. |
+ | | Raise an :exc:`FileExistsError` exception |
+ | | if it is already exists. |
+ +------------------+---------------------------------------------+
| ``'a' or 'a:'`` | Open for appending with no compression. The |
| | file is created if it does not exist. |
+------------------+---------------------------------------------+
@@ -82,9 +99,9 @@
If *fileobj* is specified, it is used as an alternative to a :term:`file object`
opened in binary mode for *name*. It is supposed to be at position 0.
- For modes ``'w:gz'``, ``'r:gz'``, ``'w:bz2'``, ``'r:bz2'``, :func:`tarfile.open`
- accepts the keyword argument *compresslevel* to specify the compression level of
- the file.
+ For modes ``'w:gz'``, ``'r:gz'``, ``'w:bz2'``, ``'r:bz2'``, ``'x:gz'``,
+ ``'x:bz2'``, :func:`tarfile.open` accepts the keyword argument
+ *compresslevel* to specify the compression level of the file.
For special purposes, there is a second format for *mode*:
``'filemode|[compression]'``. :func:`tarfile.open` will return a :class:`TarFile`
@@ -127,6 +144,8 @@
| | writing. |
+-------------+--------------------------------------------+
+ .. versionchanged:: 3.5
+ The ``'x'`` (exclusive creation) mode was added.
.. class:: TarFile
@@ -252,8 +271,8 @@
In this case, the file object's :attr:`name` attribute is used if it exists.
*mode* is either ``'r'`` to read from an existing archive, ``'a'`` to append
- data to an existing file or ``'w'`` to create a new file overwriting an existing
- one.
+ data to an existing file, ``'w'`` to create a new file overwriting an existing
+ one or ``'x'`` to create a new file only if it's not exists.
If *fileobj* is given, it is used for reading or writing data. If it can be
determined, *mode* is overridden by *fileobj*'s mode. *fileobj* will be used
@@ -292,12 +311,14 @@
to be handled. The default settings will work for most users.
See section :ref:`tar-unicode` for in-depth information.
+ The *pax_headers* argument is an optional dictionary of strings which
+ will be added as a pax global header if *format* is :const:`PAX_FORMAT`.
+
.. versionchanged:: 3.2
Use ``'surrogateescape'`` as the default for the *errors* argument.
- The *pax_headers* argument is an optional dictionary of strings which
- will be added as a pax global header if *format* is :const:`PAX_FORMAT`.
-
+ .. versionchanged:: 3.5
+ The ``'x'`` (exclusive creation) mode was added.
.. classmethod:: TarFile.open(...)
diff --git a/Doc/whatsnew/3.5.rst b/Doc/whatsnew/3.5.rst
--- a/Doc/whatsnew/3.5.rst
+++ b/Doc/whatsnew/3.5.rst
@@ -334,6 +334,12 @@
:meth:`socket.socket.send`.
(Contributed by Giampaolo Rodola' in :issue:`17552`.)
+tarfile
+-------
+
+* The :func:`tarfile.open` function now supports ``'x'`` (exclusive creation)
+ mode. (Contributed by Berker Peksag in :issue:`21717`.)
+
time
----
diff --git a/Lib/tarfile.py b/Lib/tarfile.py
--- a/Lib/tarfile.py
+++ b/Lib/tarfile.py
@@ -1409,9 +1409,9 @@
can be determined, `mode' is overridden by `fileobj's mode.
`fileobj' is not closed, when TarFile is closed.
"""
- modes = {"r": "rb", "a": "r+b", "w": "wb"}
+ modes = {"r": "rb", "a": "r+b", "w": "wb", "x": "xb"}
if mode not in modes:
- raise ValueError("mode must be 'r', 'a' or 'w'")
+ raise ValueError("mode must be 'r', 'a', 'w' or 'x'")
self.mode = mode
self._mode = modes[mode]
@@ -1524,6 +1524,15 @@
'w:bz2' open for writing with bzip2 compression
'w:xz' open for writing with lzma compression
+ 'x' or 'x:' create a tarfile exclusively without compression, raise
+ an exception if the file is already created
+ 'x:gz' create an gzip compressed tarfile, raise an exception
+ if the file is already created
+ 'x:bz2' create an bzip2 compressed tarfile, raise an exception
+ if the file is already created
+ 'x:xz' create an lzma compressed tarfile, raise an exception
+ if the file is already created
+
'r|*' open a stream of tar blocks with transparent compression
'r|' open an uncompressed stream of tar blocks for reading
'r|gz' open a gzip compressed stream of tar blocks
@@ -1582,7 +1591,7 @@
t._extfileobj = False
return t
- elif mode in ("a", "w"):
+ elif mode in ("a", "w", "x"):
return cls.taropen(name, mode, fileobj, **kwargs)
raise ValueError("undiscernible mode")
@@ -1591,8 +1600,8 @@
def taropen(cls, name, mode="r", fileobj=None, **kwargs):
"""Open uncompressed tar archive name for reading or writing.
"""
- if mode not in ("r", "a", "w"):
- raise ValueError("mode must be 'r', 'a' or 'w'")
+ if mode not in ("r", "a", "w", "x"):
+ raise ValueError("mode must be 'r', 'a', 'w' or 'x'")
return cls(name, mode, fileobj, **kwargs)
@classmethod
@@ -1600,8 +1609,8 @@
"""Open gzip compressed tar archive name for reading or writing.
Appending is not allowed.
"""
- if mode not in ("r", "w"):
- raise ValueError("mode must be 'r' or 'w'")
+ if mode not in ("r", "w", "x"):
+ raise ValueError("mode must be 'r', 'w' or 'x'")
try:
import gzip
@@ -1634,8 +1643,8 @@
"""Open bzip2 compressed tar archive name for reading or writing.
Appending is not allowed.
"""
- if mode not in ("r", "w"):
- raise ValueError("mode must be 'r' or 'w'.")
+ if mode not in ("r", "w", "x"):
+ raise ValueError("mode must be 'r', 'w' or 'x'")
try:
import bz2
@@ -1663,8 +1672,8 @@
"""Open lzma compressed tar archive name for reading or writing.
Appending is not allowed.
"""
- if mode not in ("r", "w"):
- raise ValueError("mode must be 'r' or 'w'")
+ if mode not in ("r", "w", "x"):
+ raise ValueError("mode must be 'r', 'w' or 'x'")
try:
import lzma
@@ -1751,7 +1760,7 @@
addfile(). If given, `arcname' specifies an alternative name for the
file in the archive.
"""
- self._check("aw")
+ self._check("awx")
# When fileobj is given, replace name by
# fileobj's real name.
@@ -1885,7 +1894,7 @@
TarInfo object, if it returns None the TarInfo object will be
excluded from the archive.
"""
- self._check("aw")
+ self._check("awx")
if arcname is None:
arcname = name
@@ -1942,7 +1951,7 @@
On Windows platforms, `fileobj' should always be opened with mode
'rb' to avoid irritation about the file size.
"""
- self._check("aw")
+ self._check("awx")
tarinfo = copy.copy(tarinfo)
diff --git a/Lib/test/test_tarfile.py b/Lib/test/test_tarfile.py
--- a/Lib/test/test_tarfile.py
+++ b/Lib/test/test_tarfile.py
@@ -1428,6 +1428,88 @@
("longlnk/" * 127) + "longlink_")
+class CreateTest(TarTest, unittest.TestCase):
+
+ prefix = "x:"
+
+ file_path = os.path.join(TEMPDIR, "spameggs42")
+
+ def setUp(self):
+ support.unlink(tmpname)
+
+ @classmethod
+ def setUpClass(cls):
+ with open(cls.file_path, "wb") as fobj:
+ fobj.write(b"aaa")
+
+ @classmethod
+ def tearDownClass(cls):
+ support.unlink(cls.file_path)
+
+ def test_create(self):
+ with tarfile.open(tmpname, self.mode) as tobj:
+ tobj.add(self.file_path)
+
+ with self.taropen(tmpname) as tobj:
+ names = tobj.getnames()
+ self.assertEqual(len(names), 1)
+ self.assertIn('spameggs42', names[0])
+
+ def test_create_existing(self):
+ with tarfile.open(tmpname, self.mode) as tobj:
+ tobj.add(self.file_path)
+
+ with self.assertRaises(FileExistsError):
+ tobj = tarfile.open(tmpname, self.mode)
+
+ with self.taropen(tmpname) as tobj:
+ names = tobj.getnames()
+ self.assertEqual(len(names), 1)
+ self.assertIn('spameggs42', names[0])
+
+ def test_create_taropen(self):
+ with self.taropen(tmpname, "x") as tobj:
+ tobj.add(self.file_path)
+
+ with self.taropen(tmpname) as tobj:
+ names = tobj.getnames()
+ self.assertEqual(len(names), 1)
+ self.assertIn('spameggs42', names[0])
+
+ def test_create_existing_taropen(self):
+ with self.taropen(tmpname, "x") as tobj:
+ tobj.add(self.file_path)
+
+ with self.assertRaises(FileExistsError):
+ with self.taropen(tmpname, "x"):
+ pass
+
+ with self.taropen(tmpname) as tobj:
+ names = tobj.getnames()
+ self.assertEqual(len(names), 1)
+ self.assertIn("spameggs42", names[0])
+
+
+class GzipCreateTest(GzipTest, CreateTest):
+ pass
+
+
+class Bz2CreateTest(Bz2Test, CreateTest):
+ pass
+
+
+class LzmaCreateTest(LzmaTest, CreateTest):
+ pass
+
+
+class CreateWithXModeTest(CreateTest):
+
+ prefix = "x"
+
+ test_create_taropen = None
+ test_create_existing_taropen = None
+
+
@unittest.skipUnless(hasattr(os, "link"), "Missing hardlink implementation")
class HardlinkTest(unittest.TestCase):
# Test the creation of LNKTYPE (hardlink) members in an archive.
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -13,6 +13,8 @@
Library
-------
+- Issue #21717: tarfile.open() now supports 'x' (exclusive creation) mode.
+
- Issue #23344: marshal.dumps() is now 20-25% faster on average.
- Issue #20416: marshal.dumps() with protocols 3 and 4 is now 40-50% faster on
--
Repository URL: https://hg.python.org/cpython
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