summaryrefslogtreecommitdiff
path: root/coverage/backward.py
blob: 8d72811710696e6f00ad2775541ed38443d47e97 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
"""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=redefined-builtin
# pylint: disable=import-error
# pylint: disable=no-member
# pylint: disable=unused-import
# pylint: disable=no-name-in-module

import os, re, sys

# 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

# A function to iterate listlessly over a dict's items.
try:
    {}.iteritems
except AttributeError:
    def iitems(d):
        """Produce the items from dict `d`."""
        return d.items()
else:
    def iitems(d):
        """Produce the items from dict `d`."""
        return d.iteritems()

# Reading Python source and interpreting the coding comment is a big deal.
if sys.version_info >= (3, 0):
    # Python 3.2 provides `tokenize.open`, the best way to open source files.
    import tokenize
    try:
        open_python_source = tokenize.open     # pylint: disable=E1101
    except AttributeError:
        from io import TextIOWrapper
        detect_encoding = tokenize.detect_encoding  # pylint: disable=E1101
        # Copied from the 3.2 stdlib:
        def open_python_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
else:
    def open_python_source(fname):
        """Open a source file the best way."""
        return open(fname, "rU")


# 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')

    def binary_bytes(byte_values):
        """Produce a byte string with the ints from `byte_values`."""
        return bytes(byte_values)

    def byte_to_int(byte_value):
        """Turn an element of a bytes object into an int."""
        return byte_value

    def bytes_to_ints(bytes_value):
        """Turn a bytes object into a sequence of ints."""
        # In Py3, iterating bytes gives ints.
        return bytes_value

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

    def binary_bytes(byte_values):
        """Produce a byte string with the ints from `byte_values`."""
        return "".join(chr(b) for b in byte_values)

    def byte_to_int(byte_value):
        """Turn an element of a bytes object into an int."""
        return ord(byte_value)

    def bytes_to_ints(bytes_value):
        """Turn a bytes object into a sequence of ints."""
        for byte in bytes_value:
            yield ord(byte)

# Md5 is available in different places.
try:
    import hashlib
    md5 = hashlib.md5
except ImportError:
    import md5
    md5 = md5.new


# imp was deprecated in Python 3.4
try:
    import importlib, importlib.util
    imp = None
except ImportError:
    importlib = None

# we only want to use importlib if it has everything we need.
try:
    importlib.util.find_spec
except Exception:
    import imp
    importlib = None

try:
    PYC_MAGIC_NUMBER = importlib.util.MAGIC_NUMBER
except AttributeError:
    PYC_MAGIC_NUMBER = imp.get_magic()