diff options
| -rw-r--r-- | Doc/library/gzip.rst | 11 | ||||
| -rw-r--r-- | Lib/gzip.py | 21 | ||||
| -rw-r--r-- | Lib/test/test_gzip.py | 63 | ||||
| -rw-r--r-- | Misc/NEWS | 5 |
4 files changed, 95 insertions, 5 deletions
diff --git a/Doc/library/gzip.rst b/Doc/library/gzip.rst index c6f9ef8..fa73bba 100644 --- a/Doc/library/gzip.rst +++ b/Doc/library/gzip.rst @@ -24,7 +24,7 @@ For other archive formats, see the :mod:`bz2`, :mod:`zipfile`, and The module defines the following items: -.. class:: GzipFile([filename[, mode[, compresslevel[, fileobj]]]]) +.. class:: GzipFile([filename[, mode[, compresslevel[, fileobj[, mtime]]]]]) Constructor for the :class:`GzipFile` class, which simulates most of the methods of a file object, with the exception of the :meth:`readinto` and @@ -52,6 +52,15 @@ The module defines the following items: level of compression; ``1`` is fastest and produces the least compression, and ``9`` is slowest and produces the most compression. The default is ``9``. + The *mtime* argument is an optional numeric timestamp to be written to + the stream when compressing. All :program:`gzip`compressed streams are + required to contain a timestamp. If omitted or ``None``, the current + time is used. This module ignores the timestamp when decompressing; + however, some programs, such as :program:`gunzip`\ , make use of it. + The format of the timestamp is the same as that of the return value of + ``time.time()`` and of the ``st_mtime`` member of the object returned + by ``os.stat()``. + Calling a :class:`GzipFile` object's :meth:`close` method does not close *fileobj*, since you might wish to append more material after the compressed data. This also allows you to pass a :class:`StringIO` object opened for diff --git a/Lib/gzip.py b/Lib/gzip.py index 11d5571..560a722 100644 --- a/Lib/gzip.py +++ b/Lib/gzip.py @@ -54,7 +54,7 @@ class GzipFile: max_read_chunk = 10 * 1024 * 1024 # 10Mb def __init__(self, filename=None, mode=None, - compresslevel=9, fileobj=None): + compresslevel=9, fileobj=None, mtime=None): """Constructor for the GzipFile class. At least one of fileobj and filename must be given a @@ -81,6 +81,15 @@ class GzipFile: level of compression; 1 is fastest and produces the least compression, and 9 is slowest and produces the most compression. The default is 9. + The mtime argument is an optional numeric timestamp to be written + to the stream when compressing. All gzip compressed streams + are required to contain a timestamp. If omitted or None, the + current time is used. This module ignores the timestamp when + decompressing; however, some programs, such as gunzip, make use + of it. The format of the timestamp is the same as that of the + return value of time.time() and of the st_mtime member of the + object returned by os.stat(). + """ # guarantee the file is opened in binary mode on platforms @@ -119,6 +128,7 @@ class GzipFile: self.fileobj = fileobj self.offset = 0 + self.mtime = mtime if self.mode == WRITE: self._write_gzip_header() @@ -157,7 +167,10 @@ class GzipFile: if fname: flags = FNAME self.fileobj.write(chr(flags).encode('latin-1')) - write32u(self.fileobj, int(time.time())) + mtime = self.mtime + if mtime is None: + mtime = time.time() + write32u(self.fileobj, int(mtime)) self.fileobj.write(b'\002') self.fileobj.write(b'\377') if fname: @@ -175,10 +188,10 @@ class GzipFile: if method != 8: raise IOError('Unknown compression method') flag = ord( self.fileobj.read(1) ) - # modtime = self.fileobj.read(4) + self.mtime = read32(self.fileobj) # extraflag = self.fileobj.read(1) # os = self.fileobj.read(1) - self.fileobj.read(6) + self.fileobj.read(2) if flag & FEXTRA: # Read & discard the extra field, if present diff --git a/Lib/test/test_gzip.py b/Lib/test/test_gzip.py index d28c024..e758826 100644 --- a/Lib/test/test_gzip.py +++ b/Lib/test/test_gzip.py @@ -6,6 +6,7 @@ import unittest from test import support import os import gzip +import struct data1 = b""" int length=DEFAULTALLOC, err = Z_OK; @@ -160,6 +161,68 @@ class TestGzip(unittest.TestCase): self.assertEqual(f.name, self.filename) f.close() + def test_mtime(self): + mtime = 123456789 + fWrite = gzip.GzipFile(self.filename, 'w', mtime = mtime) + fWrite.write(data1) + fWrite.close() + + fRead = gzip.GzipFile(self.filename) + dataRead = fRead.read() + self.assertEqual(dataRead, data1) + self.assert_(hasattr(fRead, 'mtime')) + self.assertEqual(fRead.mtime, mtime) + fRead.close() + + def test_metadata(self): + mtime = 123456789 + + fWrite = gzip.GzipFile(self.filename, 'w', mtime = mtime) + fWrite.write(data1) + fWrite.close() + + fRead = open(self.filename, 'rb') + + # see RFC 1952: http://www.faqs.org/rfcs/rfc1952.html + + idBytes = fRead.read(2) + self.assertEqual(idBytes, b'\x1f\x8b') # gzip ID + + cmByte = fRead.read(1) + self.assertEqual(cmByte, b'\x08') # deflate + + flagsByte = fRead.read(1) + self.assertEqual(flagsByte, b'\x08') # only the FNAME flag is set + + mtimeBytes = fRead.read(4) + self.assertEqual(mtimeBytes, struct.pack('<i', mtime)) # little-endian + + xflByte = fRead.read(1) + self.assertEqual(xflByte, b'\x02') # maximum compression + + osByte = fRead.read(1) + self.assertEqual(osByte, b'\xff') # OS "unknown" (OS-independent) + + # Since the FNAME flag is set, the zero-terminated filename follows. + # RFC 1952 specifies that this is the name of the input file, if any. + # However, the gzip module defaults to storing the name of the output + # file in this field. + expected = self.filename.encode('Latin-1') + b'\x00' + nameBytes = fRead.read(len(expected)) + self.assertEqual(nameBytes, expected) + + # Since no other flags were set, the header ends here. + # Rather than process the compressed data, let's seek to the trailer. + fRead.seek(os.stat(self.filename).st_size - 8) + + crc32Bytes = fRead.read(4) # CRC32 of uncompressed data [data1] + self.assertEqual(crc32Bytes, b'\xaf\xd7d\x83') + + isizeBytes = fRead.read(4) + self.assertEqual(isizeBytes, struct.pack('<i', len(data1))) + + fRead.close() + def test_main(verbose=None): support.run_unittest(TestGzip) @@ -82,6 +82,11 @@ Core and Builtins Library ------- +- Issue #4272: Add an optional argument to the GzipFile constructor to override + the timestamp in the gzip stream. The default value remains the current time. + The information can be used by e.g. gunzip when decompressing. Patch by + Jacques Frechet. + - Restore Python 2.3 compatibility for decimal.py. - Issue #3638: Remove functions from _tkinter module level that depend on |