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

Files @ cdf10b3df899

Branch filter:

Location: kallithea/rhodecode/lib/vcs/utils/lazy.py

cdf10b3df899 1.5 KiB text/x-python Show Annotation Show as Raw Download as Raw

Jonathan Sternberg

Allow RhodeCode maintainers to specify a custom bug tracker.

This allows people who maintain large RhodeCode installations to setup their
own bug tracker and respond to requests against their specific installation.
The maintainer is then free to forward problems with RhodeCode to the
canonical issue tracker on bitbucket.

If the config option "bugtracker" is present, its value will be used with the
"Report a bug" button. If left blank, this disables the button. If no value is
present, then the default is used. This is so that the new config option
doesn't break installations of RhodeCode upgrading to a newer version and to
allow easier installation for the common use case.

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