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Diffstat (limited to 'scripts/external_libs/zmq/eventloop/minitornado/util.py')
| -rw-r--r-- | scripts/external_libs/zmq/eventloop/minitornado/util.py | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/scripts/external_libs/zmq/eventloop/minitornado/util.py b/scripts/external_libs/zmq/eventloop/minitornado/util.py new file mode 100644 index 00000000..c1e2eb95 --- /dev/null +++ b/scripts/external_libs/zmq/eventloop/minitornado/util.py @@ -0,0 +1,184 @@ +"""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 + + +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 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]) + + +# 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 type('') is not type(b''): + def u(s): + return s + bytes_type = bytes + unicode_type = str + basestring_type = str +else: + def u(s): + return s.decode('unicode_escape') + bytes_type = str + unicode_type = unicode + basestring_type = basestring + + +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 +""") + + +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, **kwargs): + base = cls.configurable_base() + args = {} + if cls is base: + impl = cls.configured_class() + if base.__impl_kwargs: + args.update(base.__impl_kwargs) + else: + impl = cls + args.update(kwargs) + instance = super(Configurable, cls).__new__(impl) + # initialize vs __init__ chosen for compatiblity with AsyncHTTPClient + # singleton magic. If we get rid of that we can switch to __init__ + # here too. + instance.initialize(**args) + 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__``. + """ + + @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_type)): + 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] + |