/usr/lib/python2.7/dist-packages/zmq/eventloop/minitornado/util.py is in python-zmq 15.2.0-0ubuntu4.
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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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 | """Miscellaneous utility functions and classes.
This module is used internally by Tornado. It is not necessarily expected
that the functions and classes defined here will be useful to other
applications, but they are documented here in case they are.
The one public-facing part of this module is the `Configurable` class
and its `~Configurable.configure` method, which becomes a part of the
interface of its subclasses, including `.AsyncHTTPClient`, `.IOLoop`,
and `.Resolver`.
"""
from __future__ import absolute_import, division, print_function, with_statement
import sys
# Fake unicode literal support: Python 3.2 doesn't have the u'' marker for
# literal strings, and alternative solutions like "from __future__ import
# unicode_literals" have other problems (see PEP 414). u() can be applied
# to ascii strings that include \u escapes (but they must not contain
# literal non-ascii characters).
if not isinstance(b'', type('')):
def u(s):
return s
unicode_type = str
basestring_type = str
else:
def u(s):
return s.decode('unicode_escape')
# These names don't exist in py3, so use noqa comments to disable
# warnings in flake8.
unicode_type = unicode # noqa
basestring_type = basestring # noqa
def import_object(name):
"""Imports an object by name.
import_object('x') is equivalent to 'import x'.
import_object('x.y.z') is equivalent to 'from x.y import z'.
>>> import tornado.escape
>>> import_object('tornado.escape') is tornado.escape
True
>>> import_object('tornado.escape.utf8') is tornado.escape.utf8
True
>>> import_object('tornado') is tornado
True
>>> import_object('tornado.missing_module')
Traceback (most recent call last):
...
ImportError: No module named missing_module
"""
if isinstance(name, unicode_type) and str is not unicode_type:
# On python 2 a byte string is required.
name = name.encode('utf-8')
if name.count('.') == 0:
return __import__(name, None, None)
parts = name.split('.')
obj = __import__('.'.join(parts[:-1]), None, None, [parts[-1]], 0)
try:
return getattr(obj, parts[-1])
except AttributeError:
raise ImportError("No module named %s" % parts[-1])
# Deprecated alias that was used before we dropped py25 support.
# Left here in case anyone outside Tornado is using it.
bytes_type = bytes
if sys.version_info > (3,):
exec("""
def raise_exc_info(exc_info):
raise exc_info[1].with_traceback(exc_info[2])
def exec_in(code, glob, loc=None):
if isinstance(code, str):
code = compile(code, '<string>', 'exec', dont_inherit=True)
exec(code, glob, loc)
""")
else:
exec("""
def raise_exc_info(exc_info):
raise exc_info[0], exc_info[1], exc_info[2]
def exec_in(code, glob, loc=None):
if isinstance(code, basestring):
# exec(string) inherits the caller's future imports; compile
# the string first to prevent that.
code = compile(code, '<string>', 'exec', dont_inherit=True)
exec code in glob, loc
""")
def errno_from_exception(e):
"""Provides the errno from an Exception object.
There are cases that the errno attribute was not set so we pull
the errno out of the args but if someone instantiates an Exception
without any args you will get a tuple error. So this function
abstracts all that behavior to give you a safe way to get the
errno.
"""
if hasattr(e, 'errno'):
return e.errno
elif e.args:
return e.args[0]
else:
return None
class Configurable(object):
"""Base class for configurable interfaces.
A configurable interface is an (abstract) class whose constructor
acts as a factory function for one of its implementation subclasses.
The implementation subclass as well as optional keyword arguments to
its initializer can be set globally at runtime with `configure`.
By using the constructor as the factory method, the interface
looks like a normal class, `isinstance` works as usual, etc. This
pattern is most useful when the choice of implementation is likely
to be a global decision (e.g. when `~select.epoll` is available,
always use it instead of `~select.select`), or when a
previously-monolithic class has been split into specialized
subclasses.
Configurable subclasses must define the class methods
`configurable_base` and `configurable_default`, and use the instance
method `initialize` instead of ``__init__``.
"""
__impl_class = None
__impl_kwargs = None
def __new__(cls, *args, **kwargs):
base = cls.configurable_base()
init_kwargs = {}
if cls is base:
impl = cls.configured_class()
if base.__impl_kwargs:
init_kwargs.update(base.__impl_kwargs)
else:
impl = cls
init_kwargs.update(kwargs)
instance = super(Configurable, cls).__new__(impl)
# initialize vs __init__ chosen for compatibility with AsyncHTTPClient
# singleton magic. If we get rid of that we can switch to __init__
# here too.
instance.initialize(*args, **init_kwargs)
return instance
@classmethod
def configurable_base(cls):
"""Returns the base class of a configurable hierarchy.
This will normally return the class in which it is defined.
(which is *not* necessarily the same as the cls classmethod parameter).
"""
raise NotImplementedError()
@classmethod
def configurable_default(cls):
"""Returns the implementation class to be used if none is configured."""
raise NotImplementedError()
def initialize(self):
"""Initialize a `Configurable` subclass instance.
Configurable classes should use `initialize` instead of ``__init__``.
.. versionchanged:: 4.2
Now accepts positional arguments in addition to keyword arguments.
"""
@classmethod
def configure(cls, impl, **kwargs):
"""Sets the class to use when the base class is instantiated.
Keyword arguments will be saved and added to the arguments passed
to the constructor. This can be used to set global defaults for
some parameters.
"""
base = cls.configurable_base()
if isinstance(impl, (unicode_type, bytes)):
impl = import_object(impl)
if impl is not None and not issubclass(impl, cls):
raise ValueError("Invalid subclass of %s" % cls)
base.__impl_class = impl
base.__impl_kwargs = kwargs
@classmethod
def configured_class(cls):
"""Returns the currently configured class."""
base = cls.configurable_base()
if cls.__impl_class is None:
base.__impl_class = cls.configurable_default()
return base.__impl_class
@classmethod
def _save_configuration(cls):
base = cls.configurable_base()
return (base.__impl_class, base.__impl_kwargs)
@classmethod
def _restore_configuration(cls, saved):
base = cls.configurable_base()
base.__impl_class = saved[0]
base.__impl_kwargs = saved[1]
def timedelta_to_seconds(td):
"""Equivalent to td.total_seconds() (introduced in python 2.7)."""
return (td.microseconds + (td.seconds + td.days * 24 * 3600) * 10 ** 6) / float(10 ** 6)
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