py3compat.py

# -*- coding: utf-8 -*-
#
# Copyright © 2012-2013 Pierre Raybaut
# Licensed under the terms of the MIT License
# (see spyderlib/__init__.py for details)

"""
spyderlib.py3compat
-------------------

Transitional module providing compatibility functions intended to help 
migrating from Python 2 to Python 3.

This module should be fully compatible with:
    * Python >=v2.6
    * Python 3
"""

from __future__ import print_function

import sys
import os

PY2 = sys.version[0] == '2'
PY3 = sys.version[0] == '3'


#==============================================================================
# Data types
#==============================================================================
if PY2:
    # Python 2
    TEXT_TYPES = (str, unicode)
    INT_TYPES = (int, long)
else:
    # Python 3
    TEXT_TYPES = (str,)
    INT_TYPES = (int,)
NUMERIC_TYPES = tuple(list(INT_TYPES) + [float, complex])


#==============================================================================
# Renamed/Reorganized modules
#==============================================================================
if PY2:
    # Python 2
    import __builtin__ as builtins
    import ConfigParser as configparser
    try:
        import _winreg as winreg
    except ImportError:
        pass
    from sys import maxint as maxsize
    try:
        import CStringIO as io
    except ImportError:
        import StringIO as io
    try:
        import cPickle as pickle
    except ImportError:
        import pickle
    from UserDict import DictMixin as MutableMapping
    import thread as _thread
    import repr as reprlib
else:
    # Python 3
    import builtins
    import configparser
    try:
        import winreg
    except ImportError:
        pass
    from sys import maxsize
    import io
    import pickle
    from collections import MutableMapping
    import _thread
    import reprlib


#==============================================================================
# Strings
#==============================================================================
if PY2:
    # Python 2
    import codecs
    def u(obj):
        """Make unicode object"""
        return codecs.unicode_escape_decode(obj)[0]
else:
    # Python 3
    def u(obj):
        """Return string as it is"""
        return obj

def is_text_string(obj):
    """Return True if `obj` is a text string, False if it is anything else,
    like binary data (Python 3) or QString (Python 2, PyQt API #1)"""
    if PY2:
        # Python 2
        return isinstance(obj, basestring)
    else:
        # Python 3
        return isinstance(obj, str)

def is_binary_string(obj):
    """Return True if `obj` is a binary string, False if it is anything else"""
    if PY2:
        # Python 2
        return isinstance(obj, str)
    else:
        # Python 3
        return isinstance(obj, bytes)

def is_string(obj):
    """Return True if `obj` is a text or binary Python string object,
    False if it is anything else, like a QString (Python 2, PyQt API #1)"""
    return is_text_string(obj) or is_binary_string(obj)

def is_unicode(obj):
    """Return True if `obj` is unicode"""
    if PY2:
        # Python 2
        return isinstance(obj, unicode)
    else:
        # Python 3
        return isinstance(obj, str)

def to_text_string(obj, encoding=None):
    """Convert `obj` to (unicode) text string"""
    if PY2:
        # Python 2
        if encoding is None:
            return unicode(obj)
        else:
            return unicode(obj, encoding)
    else:
        # Python 3
        if encoding is None:
            return str(obj)
        elif isinstance(obj, str):
            # In case this function is not used properly, this could happen
            return obj
        else:
            return str(obj, encoding)

def to_binary_string(obj, encoding=None):
    """Convert `obj` to binary string (bytes in Python 3, str in Python 2)"""
    if PY2:
        # Python 2
        if encoding is None:
            return str(obj)
        else:
            return obj.encode(encoding)
    else:
        # Python 3
        return bytes(obj, 'utf-8' if encoding is None else encoding)


#==============================================================================
# Function attributes
#==============================================================================
def get_func_code(func):
    """Return function code object"""
    if PY2:
        # Python 2
        return func.func_code
    else:
        # Python 3
        return func.__code__

def get_func_name(func):
    """Return function name"""
    if PY2:
        # Python 2
        return func.func_name
    else:
        # Python 3
        return func.__name__

def get_func_defaults(func):
    """Return function default argument values"""
    if PY2:
        # Python 2
        return func.func_defaults
    else:
        # Python 3
        return func.__defaults__


#==============================================================================
# Special method attributes
#==============================================================================
def get_meth_func(obj):
    """Return method function object"""
    if PY2:
        # Python 2
        return obj.im_func
    else:
        # Python 3
        return obj.__func__

def get_meth_class_inst(obj):
    """Return method class instance"""
    if PY2:
        # Python 2
        return obj.im_self
    else:
        # Python 3
        return obj.__self__

def get_meth_class(obj):
    """Return method class"""
    if PY2:
        # Python 2
        return obj.im_class
    else:
        # Python 3
        return obj.__self__.__class__


#==============================================================================
# Misc.
#==============================================================================
if PY2:
    # Python 2
    input = raw_input
    getcwd = os.getcwdu
    cmp = cmp
    import string
    str_lower = string.lower
    from itertools import izip_longest as zip_longest
else:
    # Python 3
    input = input
    getcwd = os.getcwd
    def cmp(a, b):
        return (a > b) - (a < b)
    str_lower = str.lower
    from itertools import zip_longest

def qbytearray_to_str(qba):
    """Convert QByteArray object to str in a way compatible with Python 2/3"""
    return str(bytes(qba.toHex().data()).decode())


if __name__ == '__main__':
    pass