merge the io-c branch: C implementation of the io module

The main io module now uses the C implementation.  The Python one still exists
in Lib/_pyio.py for ease of testing new features and usefulness to other
implementers.

The rewrite was done by Antoine Pitrou and Amaury Forgeot d'Arc.  I was slightly
helpful at the end. :)


Following are the log messages from the io-c branch:

Merged revisions 68683-68685,68687-68689,68693,68704,68741-68743,68745,68747,68752-68754,68756,68758,68812,68816-68817,68820-68822,68824-68825,68828,68876-68877,69037,69044,69104,69115,69194,69626-69629,69636,69638,69641-69642,69644-69654,69656-69661,69671,69677,69812-69815,69817,69827-69830,69839,69841-69845,69848,69850,69852,69854,69860,69865-69866,69868,69872-69873,69885,69888,69891-69893,69911,69913-69916,69963,70033,70035,70038,70041-70048,70067-70070,70075,70112,70133,70135,70140 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/io-c

........
  r68683 | antoine.pitrou | 2009-01-17 17:13:48 -0600 (Sat, 17 Jan 2009) | 3 lines

  Merge in changes from the io-c sandbox. Tests will follow in separate commits.
........
  r68684 | antoine.pitrou | 2009-01-17 17:17:26 -0600 (Sat, 17 Jan 2009) | 3 lines

  Fixes and additions to test_io.py
........
  r68685 | antoine.pitrou | 2009-01-17 17:22:04 -0600 (Sat, 17 Jan 2009) | 1 line

  Fix test_fileio
........
  r68687 | antoine.pitrou | 2009-01-17 17:35:11 -0600 (Sat, 17 Jan 2009) | 3 lines

  Add dependency to _iomodule.h for the various C sources
........
  r68688 | antoine.pitrou | 2009-01-17 17:38:18 -0600 (Sat, 17 Jan 2009) | 3 lines

  These precautions are not needed anymore!
........
  r68689 | antoine.pitrou | 2009-01-17 17:41:48 -0600 (Sat, 17 Jan 2009) | 3 lines

  Fix another test
........
  r68693 | antoine.pitrou | 2009-01-17 17:49:58 -0600 (Sat, 17 Jan 2009) | 3 lines

  Fix test_uu (which was using private attributes of TextIOWrapper)
........
  r68704 | antoine.pitrou | 2009-01-17 18:45:29 -0600 (Sat, 17 Jan 2009) | 3 lines

  Most io sources are Py_ssize_t-clean (I don't know about bytesio and stringio)
........
  r68741 | antoine.pitrou | 2009-01-18 15:20:30 -0600 (Sun, 18 Jan 2009) | 3 lines

  Check return type in TextIOWrapper.__next__
........
  r68742 | antoine.pitrou | 2009-01-18 15:28:48 -0600 (Sun, 18 Jan 2009) | 4 lines

  Make binary buffered readline and iteration much faster
  (8x as fast as the IOBase generic implementation)
........
  r68743 | antoine.pitrou | 2009-01-18 15:47:47 -0600 (Sun, 18 Jan 2009) | 3 lines

  Reinsert test_io_after_close (was removed by mistake)
........
  r68745 | antoine.pitrou | 2009-01-18 16:16:06 -0600 (Sun, 18 Jan 2009) | 3 lines

  Add read, read1 and write methods to BufferedIOBase
........
  r68747 | antoine.pitrou | 2009-01-18 16:35:58 -0600 (Sun, 18 Jan 2009) | 3 lines

  Kill test failure
........
  r68752 | amaury.forgeotdarc | 2009-01-18 17:05:43 -0600 (Sun, 18 Jan 2009) | 3 lines

  Fix a segfault when e.g a BufferedReader is created with a FileIO in
  read mode.
........
  r68753 | antoine.pitrou | 2009-01-18 17:13:09 -0600 (Sun, 18 Jan 2009) | 3 lines

  Add truncate() to text IO objects
........
  r68754 | antoine.pitrou | 2009-01-18 17:51:08 -0600 (Sun, 18 Jan 2009) | 3 lines

  Remove IOBase.__del__ and replace it with custom code with tp_dealloc
........
  r68756 | antoine.pitrou | 2009-01-18 18:10:16 -0600 (Sun, 18 Jan 2009) | 3 lines

  Remove irrelevant comment.
........
  r68758 | antoine.pitrou | 2009-01-18 18:36:16 -0600 (Sun, 18 Jan 2009) | 3 lines

  in importlib:_fileio._FileIO -> _io.FileIO
........
  r68812 | antoine.pitrou | 2009-01-20 14:15:51 -0600 (Tue, 20 Jan 2009) | 3 lines

  Add garbage collection support to FileIO objects
........
  r68816 | antoine.pitrou | 2009-01-20 14:56:28 -0600 (Tue, 20 Jan 2009) | 3 lines

  Add GC support to Buffered and Text IO objects
........
  r68817 | antoine.pitrou | 2009-01-20 15:19:45 -0600 (Tue, 20 Jan 2009) | 3 lines

  Add some file headers
........
  r68820 | antoine.pitrou | 2009-01-20 15:29:59 -0600 (Tue, 20 Jan 2009) | 3 lines

  Add class TextIOBase
........
  r68821 | antoine.pitrou | 2009-01-20 15:36:16 -0600 (Tue, 20 Jan 2009) | 3 lines

  Add properties to TextIOBase
........
  r68822 | antoine.pitrou | 2009-01-20 15:41:19 -0600 (Tue, 20 Jan 2009) | 3 lines

  Disable the pure Python TextIOBase class, and inject C the implementation instead
........
  r68824 | antoine.pitrou | 2009-01-20 16:36:28 -0600 (Tue, 20 Jan 2009) | 3 lines

  Fix two leaks
........
  r68825 | antoine.pitrou | 2009-01-20 16:38:29 -0600 (Tue, 20 Jan 2009) | 3 lines

  FileIO.name is just a plain attribute, we can set it directly
........
  r68828 | antoine.pitrou | 2009-01-20 17:06:33 -0600 (Tue, 20 Jan 2009) | 3 lines

  Speed up closed checks on text IO objects. Good for a 25% speedup on small ops.
........
  r68876 | antoine.pitrou | 2009-01-23 17:01:25 -0600 (Fri, 23 Jan 2009) | 3 lines

  Two typos
........
  r68877 | antoine.pitrou | 2009-01-23 18:13:20 -0600 (Fri, 23 Jan 2009) | 3 lines

  Remove two unused functions
........
  r69037 | amaury.forgeotdarc | 2009-01-27 17:10:25 -0600 (Tue, 27 Jan 2009) | 2 lines

  Update the win32 project files
........
  r69044 | antoine.pitrou | 2009-01-27 18:51:07 -0600 (Tue, 27 Jan 2009) | 3 lines

  Improve heuristic in IncrementalNewlineDecoder + some micro-optimizations
........
  r69104 | antoine.pitrou | 2009-01-29 15:23:42 -0600 (Thu, 29 Jan 2009) | 3 lines

  Fix some crashers found by Victor
........
  r69115 | hirokazu.yamamoto | 2009-01-29 20:36:28 -0600 (Thu, 29 Jan 2009) | 1 line

  Updated VC6 project file.
........
  r69194 | antoine.pitrou | 2009-02-01 16:57:18 -0600 (Sun, 01 Feb 2009) | 3 lines

  Fix downcasting warnings in 32-bit mode with 64-bit offsets (Windows)
........
  r69626 | benjamin.peterson | 2009-02-14 17:33:34 -0600 (Sat, 14 Feb 2009) | 1 line

  only catch AttributeError and UnsupportedOperation
........
  r69627 | benjamin.peterson | 2009-02-14 21:35:28 -0600 (Sat, 14 Feb 2009) | 1 line

  give the IO module its own state and store the os and locale modules in it
........
  r69628 | benjamin.peterson | 2009-02-14 22:08:32 -0600 (Sat, 14 Feb 2009) | 1 line

  put interned strings in the module state structure
........
  r69629 | benjamin.peterson | 2009-02-14 22:15:29 -0600 (Sat, 14 Feb 2009) | 1 line

  put UnsupportedOperation in the module state
........
  r69636 | benjamin.peterson | 2009-02-15 08:31:42 -0600 (Sun, 15 Feb 2009) | 1 line

  dealloc unsupported_operation
........
  r69638 | benjamin.peterson | 2009-02-15 09:24:45 -0600 (Sun, 15 Feb 2009) | 1 line

  actually test the C implementation
........
  r69641 | benjamin.peterson | 2009-02-15 10:12:37 -0600 (Sun, 15 Feb 2009) | 5 lines

  make interned strings globals again ;(

  putting them in the module state was asking for trouble when the module
  was dealloced before the classes in it were
........
  r69642 | benjamin.peterson | 2009-02-15 10:19:45 -0600 (Sun, 15 Feb 2009) | 1 line

  actually test the python implementations
........
  r69644 | antoine.pitrou | 2009-02-15 11:59:30 -0600 (Sun, 15 Feb 2009) | 3 lines

  Fix memory leak in destructor when a Python class inherits from IOBase (or an IOBase-derived type)
........
  r69645 | antoine.pitrou | 2009-02-15 12:23:26 -0600 (Sun, 15 Feb 2009) | 3 lines

  Add a warning about the embarassing state of IOBase finalization
........
  r69646 | antoine.pitrou | 2009-02-15 13:14:42 -0600 (Sun, 15 Feb 2009) | 3 lines

  Fix opening of 8-bit filenames with FileIO
........
  r69647 | antoine.pitrou | 2009-02-15 13:20:22 -0600 (Sun, 15 Feb 2009) | 3 lines

  Fix leak in FileIO constructor
........
  r69648 | antoine.pitrou | 2009-02-15 13:58:16 -0600 (Sun, 15 Feb 2009) | 3 lines

  Fix some refleaks
........
  r69649 | antoine.pitrou | 2009-02-15 14:05:13 -0600 (Sun, 15 Feb 2009) | 3 lines

  Fix a leak in IOBase.writelines
........
  r69650 | antoine.pitrou | 2009-02-15 14:11:56 -0600 (Sun, 15 Feb 2009) | 3 lines

  Fix memory leak in BufferedWriter.truncate
........
  r69651 | antoine.pitrou | 2009-02-15 14:25:34 -0600 (Sun, 15 Feb 2009) | 3 lines

  Fix a leak in TextIOWrapper.seek
........
  r69652 | antoine.pitrou | 2009-02-15 14:26:28 -0600 (Sun, 15 Feb 2009) | 3 lines

  Unify implementations of truncate for buffered objects
........
  r69653 | antoine.pitrou | 2009-02-15 15:15:15 -0600 (Sun, 15 Feb 2009) | 3 lines

  Fix more leaks in TextIOWrapper
........
  r69654 | antoine.pitrou | 2009-02-15 15:21:57 -0600 (Sun, 15 Feb 2009) | 3 lines

  Smaller chunk size for a faster test
........
  r69656 | benjamin.peterson | 2009-02-15 17:29:48 -0600 (Sun, 15 Feb 2009) | 1 line

  braces make this much clearer
........
  r69657 | benjamin.peterson | 2009-02-15 17:46:07 -0600 (Sun, 15 Feb 2009) | 1 line

  use the correct macro
........
  r69658 | antoine.pitrou | 2009-02-15 19:38:59 -0600 (Sun, 15 Feb 2009) | 5 lines

  Fix crash in test_urllib2_localnet in debug mode. It was due to an HTTPResponse
  object being revived when calling its close() method in IOBase's tp_dealloc.
  _PyIOBase_finalize() starts looking scary...
........
  r69659 | benjamin.peterson | 2009-02-15 20:55:48 -0600 (Sun, 15 Feb 2009) | 1 line

  fix segfault on initialization failing
........
  r69660 | benjamin.peterson | 2009-02-15 21:09:31 -0600 (Sun, 15 Feb 2009) | 1 line

  apparently locale.getprefferedencoding() can raise a ImportError, too
........
  r69661 | benjamin.peterson | 2009-02-15 21:54:15 -0600 (Sun, 15 Feb 2009) | 1 line

  it's amazing this worked at all; I was using the wrong structs!
........
  r69671 | benjamin.peterson | 2009-02-16 08:38:27 -0600 (Mon, 16 Feb 2009) | 1 line

  add garbage collection support to bytesio
........
  r69677 | benjamin.peterson | 2009-02-16 10:31:03 -0600 (Mon, 16 Feb 2009) | 5 lines

  reduce ImportError catching code duplication

  I'm not sure this makes the code clearer with its new gotos, but
  at least I added a big fat comment
........
  r69812 | antoine.pitrou | 2009-02-20 13:50:16 -0600 (Fri, 20 Feb 2009) | 3 lines

  _StringIO now belongs to the _io modules, rather to its own _stringio module
........
  r69813 | antoine.pitrou | 2009-02-20 13:58:22 -0600 (Fri, 20 Feb 2009) | 3 lines

  Add a test for StringIO properties
........
  r69814 | antoine.pitrou | 2009-02-20 14:06:03 -0600 (Fri, 20 Feb 2009) | 3 lines

  Reimplement a few trivial StringIO functions and properties in C
........
  r69815 | antoine.pitrou | 2009-02-20 14:13:11 -0600 (Fri, 20 Feb 2009) | 3 lines

  Add the line_buffering property to TextIOWrapper, and test for it
........
  r69817 | antoine.pitrou | 2009-02-20 14:45:50 -0600 (Fri, 20 Feb 2009) | 4 lines

  Allow IncrementalNewlineDecoder to take unicode objects as decoding input if the decoder parameter is None
  This will help rewriting StringIO to C
........
  r69827 | antoine.pitrou | 2009-02-20 19:00:30 -0600 (Fri, 20 Feb 2009) | 3 lines

  Rewrite most of StringIO in C. Some almost empty stubs remain to be converted.
........
  r69828 | antoine.pitrou | 2009-02-20 19:09:25 -0600 (Fri, 20 Feb 2009) | 3 lines

  Plug a leak, and remove an unused string
........
  r69829 | benjamin.peterson | 2009-02-20 20:02:28 -0600 (Fri, 20 Feb 2009) | 1 line

  this assertions makes more sense here
........
  r69830 | benjamin.peterson | 2009-02-20 20:03:04 -0600 (Fri, 20 Feb 2009) | 1 line

  PyModule_AddObject can fail; simplify this code with a macro
........
  r69839 | antoine.pitrou | 2009-02-21 12:54:01 -0600 (Sat, 21 Feb 2009) | 3 lines

  StringIO is now written entirely in C (and blazingly fast)
........
  r69841 | benjamin.peterson | 2009-02-21 14:05:40 -0600 (Sat, 21 Feb 2009) | 1 line

  split the Python implementation of io into another module and rewrite the tests to test both implementations
........
  r69842 | benjamin.peterson | 2009-02-21 14:10:00 -0600 (Sat, 21 Feb 2009) | 1 line

  closed is not a function
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  r69843 | benjamin.peterson | 2009-02-21 14:13:04 -0600 (Sat, 21 Feb 2009) | 1 line

  fix __all__ test
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  r69844 | benjamin.peterson | 2009-02-21 14:21:24 -0600 (Sat, 21 Feb 2009) | 1 line

  fix the rest of the Misc tests
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  r69845 | benjamin.peterson | 2009-02-21 14:26:59 -0600 (Sat, 21 Feb 2009) | 1 line

  RawIOBase is better for FileIO
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  r69848 | benjamin.peterson | 2009-02-21 15:33:53 -0600 (Sat, 21 Feb 2009) | 1 line

  fix some more tests broken by bag argument validation
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  r69850 | benjamin.peterson | 2009-02-21 16:16:42 -0600 (Sat, 21 Feb 2009) | 1 line

  make the python IncrementalNewineDecoder support a None decoder
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  r69852 | benjamin.peterson | 2009-02-21 16:36:09 -0600 (Sat, 21 Feb 2009) | 1 line

  fix a BlockingIOError.characters_written bug
........
  r69854 | benjamin.peterson | 2009-02-21 16:49:02 -0600 (Sat, 21 Feb 2009) | 1 line

  check whence
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  r69860 | benjamin.peterson | 2009-02-21 17:42:50 -0600 (Sat, 21 Feb 2009) | 1 line

  fix some of these Misbehaving io tests
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  r69865 | benjamin.peterson | 2009-02-21 18:59:52 -0600 (Sat, 21 Feb 2009) | 1 line

  don't use super here()
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  r69866 | benjamin.peterson | 2009-02-21 19:05:28 -0600 (Sat, 21 Feb 2009) | 1 line

  use implementation specific classes
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  r69868 | benjamin.peterson | 2009-02-21 22:12:05 -0600 (Sat, 21 Feb 2009) | 1 line

  use a more DRY friendly approach to injecting module contents into test classes
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  r69872 | antoine.pitrou | 2009-02-22 13:39:45 -0600 (Sun, 22 Feb 2009) | 3 lines

  Sanitize destructor behaviour of IOBase. Now Python-defined attributes can be accessed from close().
........
  r69873 | antoine.pitrou | 2009-02-22 13:50:14 -0600 (Sun, 22 Feb 2009) | 4 lines

  Only set the internal fd after it has been checked to be valid
  (otherwise, the destructor will attempt to close it)
........
  r69885 | benjamin.peterson | 2009-02-22 15:30:14 -0600 (Sun, 22 Feb 2009) | 1 line

  convert some other tests to use both io implementations
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  r69888 | antoine.pitrou | 2009-02-22 17:03:16 -0600 (Sun, 22 Feb 2009) | 3 lines

  Silence all exceptions when finalizing
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  r69891 | benjamin.peterson | 2009-02-22 17:27:24 -0600 (Sun, 22 Feb 2009) | 1 line

  convert another test to test both io implementations
........
  r69892 | benjamin.peterson | 2009-02-22 17:32:15 -0600 (Sun, 22 Feb 2009) | 1 line

  help poor people like me to find their io tests (did I miss any?)
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  r69893 | benjamin.peterson | 2009-02-22 17:37:56 -0600 (Sun, 22 Feb 2009) | 1 line

  put a big note in the test telling people to write tests for both implementations now
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  r69911 | antoine.pitrou | 2009-02-23 13:57:18 -0600 (Mon, 23 Feb 2009) | 3 lines

  expose DEFAULT_BUFFER_SIZE again (fixes a bunch of test failures)
........
  r69913 | antoine.pitrou | 2009-02-23 14:10:30 -0600 (Mon, 23 Feb 2009) | 4 lines

  Do the cyclic garbage collection tests only on the C version.
  The Python version is helpless as it uses __del__.
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  r69914 | antoine.pitrou | 2009-02-23 14:21:41 -0600 (Mon, 23 Feb 2009) | 3 lines

  Adapt test_largefile to test both implementations
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  r69915 | antoine.pitrou | 2009-02-23 14:25:14 -0600 (Mon, 23 Feb 2009) | 3 lines

  One small failure
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  r69916 | antoine.pitrou | 2009-02-23 14:28:33 -0600 (Mon, 23 Feb 2009) | 3 lines

  Add a comment, at BP's request
........
  r69963 | antoine.pitrou | 2009-02-25 09:42:59 -0600 (Wed, 25 Feb 2009) | 3 lines

  Add a test of ABC inheritance
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  r70033 | antoine.pitrou | 2009-02-27 15:49:50 -0600 (Fri, 27 Feb 2009) | 3 lines

  The base classes now are ABCs.
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  r70035 | benjamin.peterson | 2009-02-27 15:57:41 -0600 (Fri, 27 Feb 2009) | 1 line

  good house keeping
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  r70038 | antoine.pitrou | 2009-02-27 17:05:23 -0600 (Fri, 27 Feb 2009) | 4 lines

  Make the buffer allocation overflow tests specific to the C implementation, since the Python implementation resizes its buffers when needed rather than allocating them up front.
........
  r70041 | benjamin.peterson | 2009-02-27 18:26:12 -0600 (Fri, 27 Feb 2009) | 1 line

  kill java naming for sanity
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  r70042 | benjamin.peterson | 2009-02-27 18:28:53 -0600 (Fri, 27 Feb 2009) | 2 lines

  timingTest is superseded by iobench
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  r70043 | antoine.pitrou | 2009-02-27 19:13:50 -0600 (Fri, 27 Feb 2009) | 3 lines

  Remove the last traces of java naming in test_io
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  r70044 | antoine.pitrou | 2009-02-27 19:18:34 -0600 (Fri, 27 Feb 2009) | 3 lines

  Better resource cleanup
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  r70045 | antoine.pitrou | 2009-02-27 19:29:00 -0600 (Fri, 27 Feb 2009) | 3 lines

  Remove dubious uses of super(), and fix one test
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  r70046 | antoine.pitrou | 2009-02-27 19:31:00 -0600 (Fri, 27 Feb 2009) | 3 lines

  Bump up CHUNK_SIZE (no need to make the Python version look slower than it is)
........
  r70047 | benjamin.peterson | 2009-02-27 20:03:26 -0600 (Fri, 27 Feb 2009) | 1 line

  fix typo
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  r70048 | benjamin.peterson | 2009-02-27 21:35:11 -0600 (Fri, 27 Feb 2009) | 1 line

  move code to a better place
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  r70067 | benjamin.peterson | 2009-02-28 10:43:20 -0600 (Sat, 28 Feb 2009) | 4 lines

  1. make sure to undo buffered read aheads in BufferedRandom.seek()
  2. refill the buffer if have <= 0
  3. fix the last failing test_io test!
........
  r70068 | benjamin.peterson | 2009-02-28 10:57:50 -0600 (Sat, 28 Feb 2009) | 1 line

  define read1() on the python implementation's BufferedIOBase
........
  r70069 | benjamin.peterson | 2009-02-28 11:01:17 -0600 (Sat, 28 Feb 2009) | 1 line

  document read1() in BufferedIOBase
........
  r70070 | benjamin.peterson | 2009-02-28 11:06:42 -0600 (Sat, 28 Feb 2009) | 1 line

  give credit where credit is due
........
  r70075 | antoine.pitrou | 2009-02-28 13:34:59 -0600 (Sat, 28 Feb 2009) | 3 lines

  Amaury's name
........
  r70112 | antoine.pitrou | 2009-03-02 17:11:55 -0600 (Mon, 02 Mar 2009) | 4 lines

  Looks like this is necessary in order to build cleanly under Windows
  (someone correct this if it's wrong, I'm no Windows user)
........
  r70133 | benjamin.peterson | 2009-03-03 15:23:32 -0600 (Tue, 03 Mar 2009) | 1 line

  fix test_newline_property on _pyio.StringIO
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  r70135 | benjamin.peterson | 2009-03-03 15:47:30 -0600 (Tue, 03 Mar 2009) | 1 line

  fix typos and inconsistencies. thanks to Daniel Diniz
........
  r70140 | benjamin.peterson | 2009-03-03 16:21:10 -0600 (Tue, 03 Mar 2009) | 1 line

  add the test from #5266
........
diff --git a/Modules/_iobase.c b/Modules/_iobase.c
new file mode 100644
index 0000000..9ee2326
--- /dev/null
+++ b/Modules/_iobase.c
@@ -0,0 +1,905 @@
+/*
+    An implementation of the I/O abstract base classes hierarchy
+    as defined by PEP 3116 - "New I/O"
+    
+    Classes defined here: IOBase, RawIOBase.
+    
+    Written by Amaury Forgeot d'Arc and Antoine Pitrou
+*/
+
+
+#define PY_SSIZE_T_CLEAN
+#include "Python.h"
+#include "structmember.h"
+#include "_iomodule.h"
+
+/*
+ * IOBase class, an abstract class
+ */
+
+typedef struct {
+    PyObject_HEAD
+    
+    PyObject *dict;
+    PyObject *weakreflist;
+} IOBaseObject;
+
+PyDoc_STRVAR(IOBase_doc,
+    "The abstract base class for all I/O classes, acting on streams of\n"
+    "bytes. There is no public constructor.\n"
+    "\n"
+    "This class provides dummy implementations for many methods that\n"
+    "derived classes can override selectively; the default implementations\n"
+    "represent a file that cannot be read, written or seeked.\n"
+    "\n"
+    "Even though IOBase does not declare read, readinto, or write because\n"
+    "their signatures will vary, implementations and clients should\n"
+    "consider those methods part of the interface. Also, implementations\n"
+    "may raise a IOError when operations they do not support are called.\n"
+    "\n"
+    "The basic type used for binary data read from or written to a file is\n"
+    "bytes. bytearrays are accepted too, and in some cases (such as\n"
+    "readinto) needed. Text I/O classes work with str data.\n"
+    "\n"
+    "Note that calling any method (even inquiries) on a closed stream is\n"
+    "undefined. Implementations may raise IOError in this case.\n"
+    "\n"
+    "IOBase (and its subclasses) support the iterator protocol, meaning\n"
+    "that an IOBase object can be iterated over yielding the lines in a\n"
+    "stream.\n"
+    "\n"
+    "IOBase also supports the :keyword:`with` statement. In this example,\n"
+    "fp is closed after the suite of the with statment is complete:\n"
+    "\n"
+    "with open('spam.txt', 'r') as fp:\n"
+    "    fp.write('Spam and eggs!')\n");
+
+/* Use this macro whenever you want to check the internal `closed` status
+   of the IOBase object rather than the virtual `closed` attribute as returned
+   by whatever subclass. */
+
+#define IS_CLOSED(self) \
+    PyObject_HasAttrString(self, "__IOBase_closed")
+
+/* Internal methods */
+static PyObject *
+IOBase_unsupported(const char *message)
+{
+    PyErr_SetString(IO_STATE->unsupported_operation, message);
+    return NULL;
+}
+
+/* Positionning */
+
+PyDoc_STRVAR(IOBase_seek_doc,
+    "Change stream position.\n"
+    "\n"
+    "Change the stream position to byte offset offset. offset is\n"
+    "interpreted relative to the position indicated by whence.  Values\n"
+    "for whence are:\n"
+    "\n"
+    "* 0 -- start of stream (the default); offset should be zero or positive\n"
+    "* 1 -- current stream position; offset may be negative\n"
+    "* 2 -- end of stream; offset is usually negative\n"
+    "\n"
+    "Return the new absolute position.");
+
+static PyObject *
+IOBase_seek(PyObject *self, PyObject *args)
+{
+    return IOBase_unsupported("seek");
+}
+
+PyDoc_STRVAR(IOBase_tell_doc,
+             "Return current stream position.");
+
+static PyObject *
+IOBase_tell(PyObject *self, PyObject *args)
+{
+    return PyObject_CallMethod(self, "seek", "ii", 0, 1);
+}
+
+PyDoc_STRVAR(IOBase_truncate_doc,
+    "Truncate file to size bytes.\n"
+    "\n"
+    "Size defaults to the current IO position as reported by tell().  Return\n"
+    "the new size.");
+
+static PyObject *
+IOBase_truncate(PyObject *self, PyObject *args)
+{
+    return IOBase_unsupported("truncate");
+}
+
+/* Flush and close methods */
+
+PyDoc_STRVAR(IOBase_flush_doc,
+    "Flush write buffers, if applicable.\n"
+    "\n"
+    "This is not implemented for read-only and non-blocking streams.\n");
+
+static PyObject *
+IOBase_flush(PyObject *self, PyObject *args)
+{
+    /* XXX Should this return the number of bytes written??? */
+    if (IS_CLOSED(self)) {
+        PyErr_SetString(PyExc_ValueError, "I/O operation on closed file.");
+        return NULL;
+    }
+    Py_RETURN_NONE;
+}
+
+PyDoc_STRVAR(IOBase_close_doc,
+    "Flush and close the IO object.\n"
+    "\n"
+    "This method has no effect if the file is already closed.\n");
+
+static int
+IOBase_closed(PyObject *self)
+{
+    PyObject *res;
+    int closed;
+    /* This gets the derived attribute, which is *not* __IOBase_closed
+       in most cases! */
+    res = PyObject_GetAttr(self, _PyIO_str_closed);
+    if (res == NULL)
+        return 0;
+    closed = PyObject_IsTrue(res);
+    Py_DECREF(res);
+    return closed;
+}
+
+static PyObject *
+IOBase_closed_get(PyObject *self, void *context)
+{
+    return PyBool_FromLong(IS_CLOSED(self));
+}
+
+PyObject *
+_PyIOBase_checkClosed(PyObject *self, PyObject *args)
+{
+    if (IOBase_closed(self)) {
+        PyErr_SetString(PyExc_ValueError, "I/O operation on closed file.");
+        return NULL;
+    }
+    if (args == Py_True)
+        return Py_None;
+    else
+        Py_RETURN_NONE;
+}
+
+/* XXX: IOBase thinks it has to maintain its own internal state in
+   `__IOBase_closed` and call flush() by itself, but it is redundant with
+   whatever behaviour a non-trivial derived class will implement. */
+
+static PyObject *
+IOBase_close(PyObject *self, PyObject *args)
+{
+    PyObject *res;
+
+    if (IS_CLOSED(self))
+        Py_RETURN_NONE;
+
+    res = PyObject_CallMethodObjArgs(self, _PyIO_str_flush, NULL);
+    PyObject_SetAttrString(self, "__IOBase_closed", Py_True);
+    if (res == NULL) {
+        /* If flush() fails, just give up */
+        if (PyErr_ExceptionMatches(PyExc_IOError))
+            PyErr_Clear();
+        else
+            return NULL;
+    }
+    Py_XDECREF(res);
+    Py_RETURN_NONE;
+}
+
+/* Finalization and garbage collection support */
+
+int
+_PyIOBase_finalize(PyObject *self)
+{
+    PyObject *res;
+    PyObject *tp, *v, *tb;
+    int closed = 1;
+    int is_zombie;
+
+    /* If _PyIOBase_finalize() is called from a destructor, we need to
+       resurrect the object as calling close() can invoke arbitrary code. */
+    is_zombie = (Py_REFCNT(self) == 0);
+    if (is_zombie) {
+        ++Py_REFCNT(self);
+    }
+    PyErr_Fetch(&tp, &v, &tb);
+    /* If `closed` doesn't exist or can't be evaluated as bool, then the
+       object is probably in an unusable state, so ignore. */
+    res = PyObject_GetAttr(self, _PyIO_str_closed);
+    if (res == NULL)
+        PyErr_Clear();
+    else {
+        closed = PyObject_IsTrue(res);
+        Py_DECREF(res);
+        if (closed == -1)
+            PyErr_Clear();
+    }
+    if (closed == 0) {
+        res = PyObject_CallMethodObjArgs((PyObject *) self, _PyIO_str_close,
+                                          NULL);
+        /* Silencing I/O errors is bad, but printing spurious tracebacks is
+           equally as bad, and potentially more frequent (because of
+           shutdown issues). */
+        if (res == NULL)
+            PyErr_Clear();
+        else
+            Py_DECREF(res);
+    }
+    PyErr_Restore(tp, v, tb);
+    if (is_zombie) {
+        if (--Py_REFCNT(self) != 0) {
+            /* The object lives again. The following code is taken from
+               slot_tp_del in typeobject.c. */
+            Py_ssize_t refcnt = Py_REFCNT(self);
+            _Py_NewReference(self);
+            Py_REFCNT(self) = refcnt;
+            /* If Py_REF_DEBUG, _Py_NewReference bumped _Py_RefTotal, so
+             * we need to undo that. */
+            _Py_DEC_REFTOTAL;
+            /* If Py_TRACE_REFS, _Py_NewReference re-added self to the object
+             * chain, so no more to do there.
+             * If COUNT_ALLOCS, the original decref bumped tp_frees, and
+             * _Py_NewReference bumped tp_allocs:  both of those need to be
+             * undone.
+             */
+#ifdef COUNT_ALLOCS
+            --Py_TYPE(self)->tp_frees;
+            --Py_TYPE(self)->tp_allocs;
+#endif
+            return -1;
+        }
+    }
+    return 0;
+}
+
+static int
+IOBase_traverse(IOBaseObject *self, visitproc visit, void *arg)
+{
+    Py_VISIT(self->dict);
+    return 0;
+}
+
+static int
+IOBase_clear(IOBaseObject *self)
+{
+    if (_PyIOBase_finalize((PyObject *) self) < 0)
+        return -1;
+    Py_CLEAR(self->dict);
+    return 0;
+}
+
+/* Destructor */
+
+static void
+IOBase_dealloc(IOBaseObject *self)
+{
+    /* NOTE: since IOBaseObject has its own dict, Python-defined attributes
+       are still available here for close() to use.
+       However, if the derived class declares a __slots__, those slots are
+       already gone.
+    */
+    if (_PyIOBase_finalize((PyObject *) self) < 0) {
+        /* When called from a heap type's dealloc, the type will be
+           decref'ed on return (see e.g. subtype_dealloc in typeobject.c). */
+        if (PyType_HasFeature(Py_TYPE(self), Py_TPFLAGS_HEAPTYPE))
+            Py_INCREF(Py_TYPE(self));
+        return;
+    }
+    _PyObject_GC_UNTRACK(self);
+    if (self->weakreflist != NULL)
+        PyObject_ClearWeakRefs((PyObject *) self);
+    Py_CLEAR(self->dict);
+    Py_TYPE(self)->tp_free((PyObject *) self);
+}
+
+/* Inquiry methods */
+
+PyDoc_STRVAR(IOBase_seekable_doc,
+    "Return whether object supports random access.\n"
+    "\n"
+    "If False, seek(), tell() and truncate() will raise IOError.\n"
+    "This method may need to do a test seek().");
+
+static PyObject *
+IOBase_seekable(PyObject *self, PyObject *args)
+{
+    Py_RETURN_FALSE;
+}
+
+PyObject *
+_PyIOBase_checkSeekable(PyObject *self, PyObject *args)
+{
+    PyObject *res  = PyObject_CallMethodObjArgs(self, _PyIO_str_seekable, NULL);
+    if (res == NULL)
+        return NULL;
+    if (res != Py_True) {
+        Py_CLEAR(res);
+        PyErr_SetString(PyExc_IOError, "File or stream is not seekable.");
+        return NULL;
+    }
+    if (args == Py_True) {
+        Py_DECREF(res);
+    }
+    return res;
+}
+
+PyDoc_STRVAR(IOBase_readable_doc,
+    "Return whether object was opened for reading.\n"
+    "\n"
+    "If False, read() will raise IOError.");
+
+static PyObject *
+IOBase_readable(PyObject *self, PyObject *args)
+{
+    Py_RETURN_FALSE;
+}
+
+/* May be called with any object */
+PyObject *
+_PyIOBase_checkReadable(PyObject *self, PyObject *args)
+{
+    PyObject *res  = PyObject_CallMethodObjArgs(self, _PyIO_str_readable, NULL);
+    if (res == NULL)
+        return NULL;
+    if (res != Py_True) {
+        Py_CLEAR(res);
+        PyErr_SetString(PyExc_IOError, "File or stream is not readable.");
+        return NULL;
+    }
+    if (args == Py_True) {
+        Py_DECREF(res);
+    }
+    return res;
+}
+
+PyDoc_STRVAR(IOBase_writable_doc,
+    "Return whether object was opened for writing.\n"
+    "\n"
+    "If False, read() will raise IOError.");
+
+static PyObject *
+IOBase_writable(PyObject *self, PyObject *args)
+{
+    Py_RETURN_FALSE;
+}
+
+/* May be called with any object */
+PyObject *
+_PyIOBase_checkWritable(PyObject *self, PyObject *args)
+{
+    PyObject *res  = PyObject_CallMethodObjArgs(self, _PyIO_str_writable, NULL);
+    if (res == NULL)
+        return NULL;
+    if (res != Py_True) {
+        Py_CLEAR(res);
+        PyErr_SetString(PyExc_IOError, "File or stream is not writable.");
+        return NULL;
+    }
+    if (args == Py_True) {
+        Py_DECREF(res);
+    }
+    return res;
+}
+
+/* Context manager */
+
+static PyObject *
+IOBase_enter(PyObject *self, PyObject *args)
+{
+    if (_PyIOBase_checkClosed(self, Py_True) == NULL)
+        return NULL;
+
+    Py_INCREF(self);
+    return self;
+}
+
+static PyObject *
+IOBase_exit(PyObject *self, PyObject *args)
+{
+    return PyObject_CallMethodObjArgs(self, _PyIO_str_close, NULL);
+}
+
+/* Lower-level APIs */
+
+/* XXX Should these be present even if unimplemented? */
+
+PyDoc_STRVAR(IOBase_fileno_doc,
+    "Returns underlying file descriptor if one exists.\n"
+    "\n"
+    "An IOError is raised if the IO object does not use a file descriptor.\n");
+
+static PyObject *
+IOBase_fileno(PyObject *self, PyObject *args)
+{
+    return IOBase_unsupported("fileno");
+}
+
+PyDoc_STRVAR(IOBase_isatty_doc,
+    "Return whether this is an 'interactive' stream.\n"
+    "\n"
+    "Return False if it can't be determined.\n");
+
+static PyObject *
+IOBase_isatty(PyObject *self, PyObject *args)
+{
+    if (_PyIOBase_checkClosed(self, Py_True) == NULL)
+        return NULL;
+    Py_RETURN_FALSE;
+}
+
+/* Readline(s) and writelines */
+
+PyDoc_STRVAR(IOBase_readline_doc,
+    "Read and return a line from the stream.\n"
+    "\n"
+    "If limit is specified, at most limit bytes will be read.\n"
+    "\n"
+    "The line terminator is always b'\n' for binary files; for text\n"
+    "files, the newlines argument to open can be used to select the line\n"
+    "terminator(s) recognized.\n");
+
+static PyObject *
+IOBase_readline(PyObject *self, PyObject *args)
+{
+    /* For backwards compatibility, a (slowish) readline(). */
+
+    Py_ssize_t limit = -1;
+    int has_peek = 0;
+    PyObject *buffer, *result;
+    Py_ssize_t old_size = -1;
+
+    if (!PyArg_ParseTuple(args, "|n:readline", &limit)) {
+        return NULL;
+    }
+
+    if (_PyIOBase_checkClosed(self, Py_True) == NULL)
+        return NULL;
+
+    if (PyObject_HasAttrString(self, "peek"))
+        has_peek = 1;
+
+    buffer = PyByteArray_FromStringAndSize(NULL, 0);
+    if (buffer == NULL)
+        return NULL;
+
+    while (limit < 0 || Py_SIZE(buffer) < limit) {
+        Py_ssize_t nreadahead = 1;
+        PyObject *b;
+
+        if (has_peek) {
+            PyObject *readahead = PyObject_CallMethod(self, "peek", "i", 1);
+            if (readahead == NULL)
+                goto fail;
+            if (!PyBytes_Check(readahead)) {
+                PyErr_Format(PyExc_IOError,
+                             "peek() should have returned a bytes object, "
+                             "not '%.200s'", Py_TYPE(readahead)->tp_name);
+                Py_DECREF(readahead);
+                goto fail;
+            }
+            if (PyBytes_GET_SIZE(readahead) > 0) {
+                Py_ssize_t n = 0;
+                const char *buf = PyBytes_AS_STRING(readahead);
+                if (limit >= 0) {
+                    do {
+                        if (n >= PyBytes_GET_SIZE(readahead) || n >= limit)
+                            break;
+                        if (buf[n++] == '\n')
+                            break;
+                    } while (1);
+                }
+                else {
+                    do {
+                        if (n >= PyBytes_GET_SIZE(readahead))
+                            break;
+                        if (buf[n++] == '\n')
+                            break;
+                    } while (1);
+                }
+                nreadahead = n;
+            }
+            Py_DECREF(readahead);
+        }
+
+        b = PyObject_CallMethod(self, "read", "n", nreadahead);
+        if (b == NULL)
+            goto fail;
+        if (!PyBytes_Check(b)) {
+            PyErr_Format(PyExc_IOError,
+                         "read() should have returned a bytes object, "
+                         "not '%.200s'", Py_TYPE(b)->tp_name);
+            Py_DECREF(b);
+            goto fail;
+        }
+        if (PyBytes_GET_SIZE(b) == 0) {
+            Py_DECREF(b);
+            break;
+        }
+
+        old_size = PyByteArray_GET_SIZE(buffer);
+        PyByteArray_Resize(buffer, old_size + PyBytes_GET_SIZE(b));
+        memcpy(PyByteArray_AS_STRING(buffer) + old_size,
+               PyBytes_AS_STRING(b), PyBytes_GET_SIZE(b));
+
+        Py_DECREF(b);
+
+        if (PyByteArray_AS_STRING(buffer)[PyByteArray_GET_SIZE(buffer) - 1] == '\n')
+            break;
+    }
+
+    result = PyBytes_FromStringAndSize(PyByteArray_AS_STRING(buffer),
+                                       PyByteArray_GET_SIZE(buffer));
+    Py_DECREF(buffer);
+    return result;
+  fail:
+    Py_DECREF(buffer);
+    return NULL;
+}
+
+static PyObject *
+IOBase_iter(PyObject *self)
+{
+    if (_PyIOBase_checkClosed(self, Py_True) == NULL)
+        return NULL;
+
+    Py_INCREF(self);
+    return self;
+}
+
+static PyObject *
+IOBase_iternext(PyObject *self)
+{
+    PyObject *line = PyObject_CallMethodObjArgs(self, _PyIO_str_readline, NULL);
+
+    if (line == NULL)
+        return NULL;
+
+    if (PyObject_Size(line) == 0) {
+        Py_DECREF(line);
+        return NULL;
+    }
+
+    return line;
+}
+
+PyDoc_STRVAR(IOBase_readlines_doc,
+    "Return a list of lines from the stream.\n"
+    "\n"
+    "hint can be specified to control the number of lines read: no more\n"
+    "lines will be read if the total size (in bytes/characters) of all\n"
+    "lines so far exceeds hint.");
+
+static PyObject *
+IOBase_readlines(PyObject *self, PyObject *args)
+{
+    Py_ssize_t hint = -1, length = 0;
+    PyObject *hintobj = Py_None, *result;
+
+    if (!PyArg_ParseTuple(args, "|O:readlines", &hintobj)) {
+        return NULL;
+    }
+    if (hintobj != Py_None) {
+        hint = PyNumber_AsSsize_t(hintobj, PyExc_ValueError);
+        if (hint == -1 && PyErr_Occurred())
+            return NULL;
+    }
+
+    result = PyList_New(0);
+    if (result == NULL)
+        return NULL;
+
+    if (hint <= 0) {
+        /* XXX special-casing this made sense in the Python version in order
+           to remove the bytecode interpretation overhead, but it could
+           probably be removed here. */
+        PyObject *ret = PyObject_CallMethod(result, "extend", "O", self);
+        if (ret == NULL) {
+            Py_DECREF(result);
+            return NULL;
+        }
+        Py_DECREF(ret);
+        return result;
+    }
+
+    while (1) {
+        PyObject *line = PyIter_Next(self);
+        if (line == NULL) {
+            if (PyErr_Occurred()) {
+                Py_DECREF(result);
+                return NULL;
+            }
+            else
+                break; /* StopIteration raised */
+        }
+
+        if (PyList_Append(result, line) < 0) {
+            Py_DECREF(line);
+            Py_DECREF(result);
+            return NULL;
+        }
+        length += PyObject_Size(line);
+        Py_DECREF(line);
+
+        if (length > hint)
+            break;
+    }
+    return result;
+}
+
+static PyObject *
+IOBase_writelines(PyObject *self, PyObject *args)
+{
+    PyObject *lines, *iter, *res;
+
+    if (!PyArg_ParseTuple(args, "O:writelines", &lines)) {
+        return NULL;
+    }
+
+    if (_PyIOBase_checkClosed(self, Py_True) == NULL)
+        return NULL;
+
+    iter = PyObject_GetIter(lines);
+    if (iter == NULL)
+        return NULL;
+
+    while (1) {
+        PyObject *line = PyIter_Next(iter);
+        if (line == NULL) {
+            if (PyErr_Occurred()) {
+                Py_DECREF(iter);
+                return NULL;
+            }
+            else
+                break; /* Stop Iteration */
+        }
+
+        res = PyObject_CallMethodObjArgs(self, _PyIO_str_write, line, NULL);
+        Py_DECREF(line);
+        if (res == NULL) {
+            Py_DECREF(iter);
+            return NULL;
+        }
+        Py_DECREF(res);
+    }
+    Py_DECREF(iter);
+    Py_RETURN_NONE;
+}
+
+static PyMethodDef IOBase_methods[] = {
+    {"seek", IOBase_seek, METH_VARARGS, IOBase_seek_doc},
+    {"tell", IOBase_tell, METH_NOARGS, IOBase_tell_doc},
+    {"truncate", IOBase_truncate, METH_VARARGS, IOBase_truncate_doc},
+    {"flush", IOBase_flush, METH_NOARGS, IOBase_flush_doc},
+    {"close", IOBase_close, METH_NOARGS, IOBase_close_doc},
+
+    {"seekable", IOBase_seekable, METH_NOARGS, IOBase_seekable_doc},
+    {"readable", IOBase_readable, METH_NOARGS, IOBase_readable_doc},
+    {"writable", IOBase_writable, METH_NOARGS, IOBase_writable_doc},
+
+    {"_checkClosed",   _PyIOBase_checkClosed, METH_NOARGS},
+    {"_checkSeekable", _PyIOBase_checkSeekable, METH_NOARGS},
+    {"_checkReadable", _PyIOBase_checkReadable, METH_NOARGS},
+    {"_checkWritable", _PyIOBase_checkWritable, METH_NOARGS},
+
+    {"fileno", IOBase_fileno, METH_NOARGS, IOBase_fileno_doc},
+    {"isatty", IOBase_isatty, METH_NOARGS, IOBase_isatty_doc},
+
+    {"__enter__", IOBase_enter, METH_NOARGS},
+    {"__exit__", IOBase_exit, METH_VARARGS},
+
+    {"readline", IOBase_readline, METH_VARARGS, IOBase_readline_doc},
+    {"readlines", IOBase_readlines, METH_VARARGS, IOBase_readlines_doc},
+    {"writelines", IOBase_writelines, METH_VARARGS},
+
+    {NULL, NULL}
+};
+
+static PyGetSetDef IOBase_getset[] = {
+    {"closed", (getter)IOBase_closed_get, NULL, NULL},
+    {0}
+};
+
+
+PyTypeObject PyIOBase_Type = {
+    PyVarObject_HEAD_INIT(NULL, 0)
+    "_io._IOBase",              /*tp_name*/
+    sizeof(IOBaseObject),       /*tp_basicsize*/
+    0,                          /*tp_itemsize*/
+    (destructor)IOBase_dealloc, /*tp_dealloc*/
+    0,                          /*tp_print*/
+    0,                          /*tp_getattr*/
+    0,                          /*tp_setattr*/
+    0,                          /*tp_compare */
+    0,                          /*tp_repr*/
+    0,                          /*tp_as_number*/
+    0,                          /*tp_as_sequence*/
+    0,                          /*tp_as_mapping*/
+    0,                          /*tp_hash */
+    0,                          /*tp_call*/
+    0,                          /*tp_str*/
+    0,                          /*tp_getattro*/
+    0,                          /*tp_setattro*/
+    0,                          /*tp_as_buffer*/
+    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE
+        | Py_TPFLAGS_HAVE_GC,   /*tp_flags*/
+    IOBase_doc,                 /* tp_doc */
+    (traverseproc)IOBase_traverse, /* tp_traverse */
+    (inquiry)IOBase_clear,      /* tp_clear */
+    0,                          /* tp_richcompare */
+    offsetof(IOBaseObject, weakreflist), /* tp_weaklistoffset */
+    IOBase_iter,                /* tp_iter */
+    IOBase_iternext,            /* tp_iternext */
+    IOBase_methods,             /* tp_methods */
+    0,                          /* tp_members */
+    IOBase_getset,              /* tp_getset */
+    0,                          /* tp_base */
+    0,                          /* tp_dict */
+    0,                          /* tp_descr_get */
+    0,                          /* tp_descr_set */
+    offsetof(IOBaseObject, dict), /* tp_dictoffset */
+    0,                          /* tp_init */
+    0,                          /* tp_alloc */
+    PyType_GenericNew,          /* tp_new */
+};
+
+
+/*
+ * RawIOBase class, Inherits from IOBase.
+ */
+PyDoc_STRVAR(RawIOBase_doc,
+             "Base class for raw binary I/O.");
+
+/*
+ * The read() method is implemented by calling readinto(); derived classes
+ * that want to support read() only need to implement readinto() as a
+ * primitive operation.  In general, readinto() can be more efficient than
+ * read().
+ *
+ * (It would be tempting to also provide an implementation of readinto() in
+ * terms of read(), in case the latter is a more suitable primitive operation,
+ * but that would lead to nasty recursion in case a subclass doesn't implement
+ * either.)
+*/
+
+static PyObject *
+RawIOBase_read(PyObject *self, PyObject *args)
+{
+    Py_ssize_t n = -1;
+    PyObject *b, *res;
+
+    if (!PyArg_ParseTuple(args, "|n:read", &n)) {
+        return NULL;
+    }
+
+    if (n < 0)
+        return PyObject_CallMethod(self, "readall", NULL);
+
+    /* TODO: allocate a bytes object directly instead and manually construct
+       a writable memoryview pointing to it. */
+    b = PyByteArray_FromStringAndSize(NULL, n);
+    if (b == NULL)
+        return NULL;
+
+    res = PyObject_CallMethodObjArgs(self, _PyIO_str_readinto, b, NULL);
+    if (res == NULL) {
+        Py_DECREF(b);
+        return NULL;
+    }
+
+    n = PyNumber_AsSsize_t(res, PyExc_ValueError);
+    Py_DECREF(res);
+    if (n == -1 && PyErr_Occurred()) {
+        Py_DECREF(b);
+        return NULL;
+    }
+
+    res = PyBytes_FromStringAndSize(PyByteArray_AsString(b), n);
+    Py_DECREF(b);
+    return res;
+}
+
+
+PyDoc_STRVAR(RawIOBase_readall_doc,
+             "Read until EOF, using multiple read() call.");
+
+static PyObject *
+RawIOBase_readall(PyObject *self, PyObject *args)
+{
+    PyObject *b = NULL;
+    Py_ssize_t cursize = 0;
+
+    while (1) {
+        Py_ssize_t length;
+        PyObject *data = PyObject_CallMethod(self, "read",
+                                             "i", DEFAULT_BUFFER_SIZE);
+
+        if (!data) {
+            Py_XDECREF(b);
+            return NULL;
+        }
+
+        if (!PyBytes_Check(data)) {
+            Py_XDECREF(b);
+            Py_DECREF(data);
+            PyErr_SetString(PyExc_TypeError, "read() should return bytes");
+            return NULL;
+        }
+
+        length = Py_SIZE(data);
+
+        if (b == NULL)
+            b = data;
+        else if (length != 0) {
+
+            _PyBytes_Resize(&b, cursize + length);
+            if (b == NULL) {
+                Py_DECREF(data);
+                return NULL;
+            }
+
+            memcpy(PyBytes_AS_STRING(b) + cursize,
+                   PyBytes_AS_STRING(data), length);
+            Py_DECREF(data);
+        }
+
+        if (length == 0)
+            break;
+    }
+
+    return b;
+
+}
+
+static PyMethodDef RawIOBase_methods[] = {
+    {"read", RawIOBase_read, METH_VARARGS},
+    {"readall", RawIOBase_readall, METH_NOARGS, RawIOBase_readall_doc},
+    {NULL, NULL}
+};
+
+PyTypeObject PyRawIOBase_Type = {
+    PyVarObject_HEAD_INIT(NULL, 0)
+    "_io._RawIOBase",                /*tp_name*/
+    0,                          /*tp_basicsize*/
+    0,                          /*tp_itemsize*/
+    0,                          /*tp_dealloc*/
+    0,                          /*tp_print*/
+    0,                          /*tp_getattr*/
+    0,                          /*tp_setattr*/
+    0,                          /*tp_compare */
+    0,                          /*tp_repr*/
+    0,                          /*tp_as_number*/
+    0,                          /*tp_as_sequence*/
+    0,                          /*tp_as_mapping*/
+    0,                          /*tp_hash */
+    0,                          /*tp_call*/
+    0,                          /*tp_str*/
+    0,                          /*tp_getattro*/
+    0,                          /*tp_setattro*/
+    0,                          /*tp_as_buffer*/
+    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,  /*tp_flags*/
+    RawIOBase_doc,              /* tp_doc */
+    0,                          /* tp_traverse */
+    0,                          /* tp_clear */
+    0,                          /* tp_richcompare */
+    0,                          /* tp_weaklistoffset */
+    0,                          /* tp_iter */
+    0,                          /* tp_iternext */
+    RawIOBase_methods,          /* tp_methods */
+    0,                          /* tp_members */
+    0,                          /* tp_getset */
+    &PyIOBase_Type,             /* tp_base */
+    0,                          /* tp_dict */
+    0,                          /* tp_descr_get */
+    0,                          /* tp_descr_set */
+    0,                          /* tp_dictoffset */
+    0,                          /* tp_init */
+    0,                          /* tp_alloc */
+    0,                          /* tp_new */
+};