kallithea Files · rhodecode/lib/vcs/utils/lazy.py

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Mads Kiilerich

settings: simplify handling of form values for hooks and extensions

This makes simpler to follow the code path and search for input input field
names. The form field names are hardcoded in the template, so generating them
programmatically in the controller do not really add any flexibility.

class _Missing(object):

    def __repr__(self):
        return 'no value'

    def __reduce__(self):
        return '_missing'

_missing = _Missing()


class LazyProperty(object):
    """
    Decorator for easier creation of ``property`` from potentially expensive to
    calculate attribute of the class.

    Usage::

      class Foo(object):
          @LazyProperty
          def bar(self):
              print 'Calculating self._bar'
              return 42

    Taken from http://blog.pythonisito.com/2008/08/lazy-descriptors.html and
    used widely.
    """

    def __init__(self, func):
        self._func = func
        self.__module__ = func.__module__
        self.__name__ = func.__name__
        self.__doc__ = func.__doc__

    def __get__(self, obj, klass=None):
        if obj is None:
            return self
        value = obj.__dict__.get(self.__name__, _missing)
        if value is _missing:
            value = self._func(obj)
            obj.__dict__[self.__name__] = value
        return value

import threading


class ThreadLocalLazyProperty(LazyProperty):
    """
    Same as above but uses thread local dict for cache storage.
    """

    def __get__(self, obj, klass=None):
        if obj is None:
            return self
        if not hasattr(obj, '__tl_dict__'):
            obj.__tl_dict__ = threading.local().__dict__

        value = obj.__tl_dict__.get(self.__name__, _missing)
        if value is _missing:
            value = self._func(obj)
            obj.__tl_dict__[self.__name__] = value
        return value