diff options
| -rw-r--r-- | Doc/library/tarfile.rst | 15 | ||||
| -rw-r--r-- | Lib/tarfile.py | 14 | ||||
| -rw-r--r-- | Lib/test/test_tarfile.py | 60 | ||||
| -rw-r--r-- | Misc/NEWS | 3 |
4 files changed, 92 insertions, 0 deletions
diff --git a/Doc/library/tarfile.rst b/Doc/library/tarfile.rst index 4d0a995..8b53b57 100644 --- a/Doc/library/tarfile.rst +++ b/Doc/library/tarfile.rst @@ -209,6 +209,14 @@ a header block followed by data blocks. It is possible to store a file in a tar archive several times. Each archive member is represented by a :class:`TarInfo` object, see :ref:`tarinfo-objects` for details. +A :class:`TarFile` object can be used as a context manager in a :keyword:`with` +statement. It will automatically be closed when the block is completed. Please +note that in the event of an exception an archive opened for writing will not +be finalized, only the internally used file object will be closed. See the +:ref:`tar-examples` section for a use case. + +.. versionadded:: 3.2 + Added support for the context manager protocol. .. class:: TarFile(name=None, mode='r', fileobj=None, format=DEFAULT_FORMAT, tarinfo=TarInfo, dereference=False, ignore_zeros=False, encoding=ENCODING, errors=None, pax_headers=None, debug=0, errorlevel=0) @@ -593,6 +601,13 @@ How to create an uncompressed tar archive from a list of filenames:: tar.add(name) tar.close() +The same example using the :keyword:`with` statement:: + + import tarfile + with tarfile.open("sample.tar", "w") as tar: + for name in ["foo", "bar", "quux"]: + tar.add(name) + How to read a gzip compressed tar archive and display some member information:: import tarfile diff --git a/Lib/tarfile.py b/Lib/tarfile.py index 7f08a98..e28b1c7 100644 --- a/Lib/tarfile.py +++ b/Lib/tarfile.py @@ -2391,6 +2391,20 @@ class TarFile(object): """ if level <= self.debug: print(msg, file=sys.stderr) + + def __enter__(self): + self._check() + return self + + def __exit__(self, type, value, traceback): + if type is None: + self.close() + else: + # An exception occurred. We must not call close() because + # it would try to write end-of-archive blocks and padding. + if not self._extfileobj: + self.fileobj.close() + self.closed = True # class TarFile class TarIter: diff --git a/Lib/test/test_tarfile.py b/Lib/test/test_tarfile.py index 792f2b9..12cf2fb 100644 --- a/Lib/test/test_tarfile.py +++ b/Lib/test/test_tarfile.py @@ -1274,6 +1274,65 @@ class MiscTest(unittest.TestCase): self.assertEqual(tarfile.itn(0xffffffff), b"\x80\x00\x00\x00\xff\xff\xff\xff") +class ContextManagerTest(unittest.TestCase): + + def test_basic(self): + with tarfile.open(tarname) as tar: + self.assertFalse(tar.closed, "closed inside runtime context") + self.assertTrue(tar.closed, "context manager failed") + + def test_closed(self): + # The __enter__() method is supposed to raise IOError + # if the TarFile object is already closed. + tar = tarfile.open(tarname) + tar.close() + with self.assertRaises(IOError): + with tar: + pass + + def test_exception(self): + # Test if the IOError exception is passed through properly. + with self.assertRaises(Exception) as exc: + with tarfile.open(tarname) as tar: + raise IOError + self.assertIsInstance(exc.exception, IOError, + "wrong exception raised in context manager") + self.assertTrue(tar.closed, "context manager failed") + + def test_no_eof(self): + # __exit__() must not write end-of-archive blocks if an + # exception was raised. + try: + with tarfile.open(tmpname, "w") as tar: + raise Exception + except: + pass + self.assertEqual(os.path.getsize(tmpname), 0, + "context manager wrote an end-of-archive block") + self.assertTrue(tar.closed, "context manager failed") + + def test_eof(self): + # __exit__() must write end-of-archive blocks, i.e. call + # TarFile.close() if there was no error. + with tarfile.open(tmpname, "w"): + pass + self.assertNotEqual(os.path.getsize(tmpname), 0, + "context manager wrote no end-of-archive block") + + def test_fileobj(self): + # Test that __exit__() did not close the external file + # object. + fobj = open(tmpname, "wb") + try: + with tarfile.open(fileobj=fobj, mode="w") as tar: + raise Exception + except: + pass + self.assertFalse(fobj.closed, "external file object was closed") + self.assertTrue(tar.closed, "context manager failed") + fobj.close() + + class GzipMiscReadTest(MiscReadTest): tarname = gzipname mode = "r:gz" @@ -1354,6 +1413,7 @@ def test_main(): AppendTest, LimitsTest, MiscTest, + ContextManagerTest, ] if hasattr(os, "link"): @@ -265,6 +265,9 @@ C-API Library ------- +- Issue #7232: Add support for the context manager protocol to the TarFile + class. + - Issue #7250: Fix info leak of os.environ across multi-run uses of wsgiref.handlers.CGIHandler. |