[Python-checkins] r85100 - in python/branches/py3k: Doc/library/gzip.rst Lib/gzip.py Lib/test/test_gzip.py Misc/NEWS

Wed Sep 29 12:49:46 CEST 2010

Author: antoine.pitrou
Date: Wed Sep 29 12:49:46 2010
New Revision: 85100
Log:
Issue #9962: GzipFile now has the peek() method.
Modified:
 python/branches/py3k/Doc/library/gzip.rst
 python/branches/py3k/Lib/gzip.py
 python/branches/py3k/Lib/test/test_gzip.py
 python/branches/py3k/Misc/NEWS
Modified: python/branches/py3k/Doc/library/gzip.rst
==============================================================================

--- python/branches/py3k/Doc/library/gzip.rst	(original)
+++ python/branches/py3k/Doc/library/gzip.rst	Wed Sep 29 12:49:46 2010
@@ -25,10 +25,10 @@
 
 .. class:: GzipFile(filename=None, mode=None, compresslevel=9, fileobj=None, mtime=None)
 
- Constructor for the :class:`GzipFile` class, which simulates most of the methods
- of a :term:`file object`, with the exception of the :meth:`readinto` and
- :meth:`truncate` methods. At least one of *fileobj* and *filename* must be
- given a non-trivial value.
+ Constructor for the :class:`GzipFile` class, which simulates most of the
+ methods of a :term:`file object`, with the exception of the :meth:`truncate`
+ method. At least one of *fileobj* and *filename* must be given a non-trivial
+ value.
 
 The new class instance is based on *fileobj*, which can be a regular file, a
 :class:`StringIO` object, or any other object which simulates a file. It
@@ -66,8 +66,9 @@
 writing as *fileobj*, and retrieve the resulting memory buffer using the
 :class:`io.BytesIO` object's :meth:`~io.BytesIO.getvalue` method.
 
- :class:`GzipFile` supports the whole :class:`io.BufferedIOBase` interface,
- including iteration and the :keyword:`with` statement.
+ :class:`GzipFile` supports the :class:`io.BufferedIOBase` interface,
+ including iteration and the :keyword:`with` statement. Only the
+ :meth:`truncate` method isn't implemented.
 
 .. versionchanged:: 3.1
 Support for the :keyword:`with` statement was added.
@@ -78,6 +79,9 @@
 .. versionchanged:: 3.2
 Support for unseekable files was added.
 
+ .. versionchanged:: 3.2
+ The :meth:`peek` method was implemented.
+
 
 .. function:: open(filename, mode='rb', compresslevel=9)
 
Modified: python/branches/py3k/Lib/gzip.py
==============================================================================
--- python/branches/py3k/Lib/gzip.py	(original)
+++ python/branches/py3k/Lib/gzip.py	Wed Sep 29 12:49:46 2010
@@ -204,7 +204,10 @@
 return self.name
 
 def __repr__(self):
- s = repr(self.fileobj)
+ fileobj = self.fileobj
+ if isinstance(fileobj, _PaddedFile):
+ fileobj = fileobj.file
+ s = repr(fileobj)
 return '<gzip ' + s[1:-1] + ' ' + hex(id(self)) + '>'
 
 def _init_write(self, filename):
@@ -336,6 +339,26 @@
 self.offset += size
 return chunk
 
+ def peek(self, n):
+ if self.mode != READ:
+ import errno
+ raise IOError(errno.EBADF, "read() on write-only GzipFile object")
+
+ # Do not return ridiculously small buffers
+ if n < 100:
+ n = 100
+ if self.extrasize == 0:
+ if self.fileobj is None:
+ return b''
+ try:
+ self._read(max(self.max_read_chunk, n))
+ except EOFError:
+ pass
+ offset = self.offset - self.extrastart
+ remaining = self.extrasize
+ assert remaining == len(self.extrabuf) - offset
+ return self.extrabuf[offset:offset + n]
+
 def _unread(self, buf):
 self.extrasize = len(buf) + self.extrasize
 self.offset -= len(buf)
Modified: python/branches/py3k/Lib/test/test_gzip.py
==============================================================================
--- python/branches/py3k/Lib/test/test_gzip.py	(original)
+++ python/branches/py3k/Lib/test/test_gzip.py	Wed Sep 29 12:49:46 2010
@@ -286,6 +286,28 @@
 with gzip.GzipFile(fileobj=buf, mode="rb") as f:
 self.assertEqual(f.read(), uncompressed)
 
+ def test_peek(self):
+ uncompressed = data1 * 200
+ with gzip.GzipFile(self.filename, "wb") as f:
+ f.write(uncompressed)
+
+ def sizes():
+ while True:
+ for n in range(5, 50, 10):
+ yield n
+
+ with gzip.GzipFile(self.filename, "rb") as f:
+ f.max_read_chunk = 33
+ nread = 0
+ for n in sizes():
+ s = f.peek(n)
+ if s == b'':
+ break
+ self.assertEqual(f.read(len(s)), s)
+ nread += len(s)
+ self.assertEqual(f.read(100), b'')
+ self.assertEqual(nread, len(uncompressed))
+
 # Testing compress/decompress shortcut functions
 
 def test_compress(self):
Modified: python/branches/py3k/Misc/NEWS
==============================================================================
--- python/branches/py3k/Misc/NEWS	(original)
+++ python/branches/py3k/Misc/NEWS	Wed Sep 29 12:49:46 2010
@@ -76,6 +76,8 @@
 Library
 -------
 
+- Issue #9962: GzipFile now has the peek() method.
+
 - Issue #9090: When a socket with a timeout fails with EWOULDBLOCK or EAGAIN,
 retry the select() loop instead of bailing out. This is because select()
 can incorrectly report a socket as ready for reading (for example, if it
