| """Add things to old Pythons so I can pretend they are newer.""" |
| |
| # This file does lots of tricky stuff, so disable a bunch of lintisms. |
| # pylint: disable=F0401,W0611,W0622 |
| # F0401: Unable to import blah |
| # W0611: Unused import blah |
| # W0622: Redefining built-in blah |
| |
| import os, sys |
| |
| # Python 2.3 doesn't have `set` |
| try: |
| set = set # new in 2.4 |
| except NameError: |
| from sets import Set as set |
| |
| # Python 2.3 doesn't have `sorted`. |
| try: |
| sorted = sorted |
| except NameError: |
| def sorted(iterable): |
| """A 2.3-compatible implementation of `sorted`.""" |
| lst = list(iterable) |
| lst.sort() |
| return lst |
| |
| # Pythons 2 and 3 differ on where to get StringIO |
| try: |
| from cStringIO import StringIO |
| BytesIO = StringIO |
| except ImportError: |
| from io import StringIO, BytesIO |
| |
| # What's a string called? |
| try: |
| string_class = basestring |
| except NameError: |
| string_class = str |
| |
| # Where do pickles come from? |
| try: |
| import cPickle as pickle |
| except ImportError: |
| import pickle |
| |
| # range or xrange? |
| try: |
| range = xrange |
| except NameError: |
| range = range |
| |
| # Exec is a statement in Py2, a function in Py3 |
| if sys.version_info >= (3, 0): |
| def exec_code_object(code, global_map): |
| """A wrapper around exec().""" |
| exec(code, global_map) |
| else: |
| # OK, this is pretty gross. In Py2, exec was a statement, but that will |
| # be a syntax error if we try to put it in a Py3 file, even if it is never |
| # executed. So hide it inside an evaluated string literal instead. |
| eval( |
| compile( |
| "def exec_code_object(code, global_map):\n" |
| " exec code in global_map\n", |
| "<exec_function>", "exec" |
| ) |
| ) |
| |
| # ConfigParser was renamed to the more-standard configparser |
| try: |
| import configparser |
| except ImportError: |
| import ConfigParser as configparser |
| |
| # Python 3.2 provides `tokenize.open`, the best way to open source files. |
| import tokenize |
| try: |
| open_source = tokenize.open # pylint: disable=E1101 |
| except AttributeError: |
| try: |
| detect_encoding = tokenize.detect_encoding # pylint: disable=E1101 |
| except AttributeError: |
| def open_source(fname): |
| """Open a source file the best way.""" |
| return open(fname, "rU") |
| else: |
| from io import TextIOWrapper |
| # Copied from the 3.2 stdlib: |
| def open_source(fname): |
| """Open a file in read only mode using the encoding detected by |
| detect_encoding(). |
| """ |
| buffer = open(fname, 'rb') |
| encoding, _ = detect_encoding(buffer.readline) |
| buffer.seek(0) |
| text = TextIOWrapper(buffer, encoding, line_buffering=True) |
| text.mode = 'r' |
| return text |
| |
| # Python 3.x is picky about bytes and strings, so provide methods to |
| # get them right, and make them no-ops in 2.x |
| if sys.version_info >= (3, 0): |
| def to_bytes(s): |
| """Convert string `s` to bytes.""" |
| return s.encode('utf8') |
| |
| def to_string(b): |
| """Convert bytes `b` to a string.""" |
| return b.decode('utf8') |
| |
| else: |
| def to_bytes(s): |
| """Convert string `s` to bytes (no-op in 2.x).""" |
| return s |
| |
| def to_string(b): |
| """Convert bytes `b` to a string (no-op in 2.x).""" |
| return b |
| |
| # A few details about writing encoded text are different in 2.x and 3.x. |
| if sys.version_info >= (3, 0): |
| def write_encoded(fname, text, encoding='utf8', errors='strict'): |
| '''Write string `text` to file names `fname`, with encoding.''' |
| # Don't use "with", so that this file is still good for old 2.x. |
| f = open(fname, 'w', encoding=encoding, errors=errors) |
| try: |
| f.write(text) |
| finally: |
| f.close() |
| else: |
| # It's not clear that using utf8 strings in 2.x is the right thing to do. |
| def write_encoded(fname, text, encoding='utf8', errors='strict'): |
| '''Write utf8 string `text` to file names `fname`, with encoding.''' |
| import codecs |
| f = codecs.open(fname, 'w', encoding=encoding, errors=errors) |
| try: |
| f.write(text.decode('utf8')) |
| finally: |
| f.close() |
| |
| # Md5 is available in different places. |
| try: |
| import hashlib |
| md5 = hashlib.md5 |
| except ImportError: |
| import md5 |
| md5 = md5.new |