Index: Doc/library/gzip.rst =================================================================== --- Doc/library/gzip.rst (revision 67109) +++ Doc/library/gzip.rst (working copy) @@ -24,7 +24,7 @@ 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 @@ 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 Index: Lib/gzip.py =================================================================== --- Lib/gzip.py (revision 67109) +++ Lib/gzip.py (working copy) @@ -42,7 +42,7 @@ 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 @@ -69,6 +69,15 @@ 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 @@ -107,6 +116,7 @@ self.fileobj = fileobj self.offset = 0 + self.mtime = mtime if self.mode == WRITE: self._write_gzip_header() @@ -140,7 +150,10 @@ if fname: flags = FNAME self.fileobj.write(chr(flags)) - write32u(self.fileobj, long(time.time())) + mtime = self.mtime + if mtime is None: + mtime = time.time() + write32u(self.fileobj, long(mtime)) self.fileobj.write('\002') self.fileobj.write('\377') if fname: @@ -158,10 +171,10 @@ 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 Index: Lib/test/test_gzip.py =================================================================== --- Lib/test/test_gzip.py (revision 67109) +++ Lib/test/test_gzip.py (working copy) @@ -6,6 +6,7 @@ from test import test_support import os import gzip +import struct data1 = """ int length=DEFAULTALLOC, err = Z_OK; @@ -160,6 +161,82 @@ 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, '\x1f\x8b') # gzip ID + + cmByte = fRead.read(1) + self.assertEqual(cmByte, '\x08') # deflate + + flagsByte = fRead.read(1) + self.assertEqual(flagsByte, '\x08') # only the FNAME flag is set + + mtimeBytes = fRead.read(4) + self.assertEqual(mtimeBytes, struct.pack('