terminatorlib.borg — terminatorlib 0.98 documentation

# Source code for terminatorlib.borg

    #!/usr/bin/python
    # Terminator by Chris Jones <cmsj@tenshu.net>
    # GPL v2 only
    """borg.py - We are the borg. Resistance is futile.

    http://code.activestate.com/recipes/66531/
    ActiveState's policy appears to be that snippets
    exist to encourage re-use, but I can not find any
    specific licencing terms.
    """

    from util import dbg

    # pylint: disable-msg=R0903
    # pylint: disable-msg=R0921
    class Borg:
        """Definition of a class that can never be duplicated. Correct usage is
        thus:

        >>> from borg import Borg
        >>> class foo(Borg):
        ...     # All attributes on a borg class *must* = None
        ...     attribute = None
        ...     def __init__(self):
        ...         Borg.__init__(self, self.__class__.__name__)
        ...     def prepare_attributes(self):
        ...         if not self.attribute:
        ...             self.attribute = []
        ...
        >>> bar = foo()
        >>> bar.prepare_attributes()

        The important thing to note is that all attributes of borg classes *must* be
        declared as being None. If you attempt to use static class attributes you
        will get unpredicted behaviour. Instead, prepare_attributes() must be called
        which will then see the attributes in the shared state, and initialise them
        if necessary."""
        __shared_state = {}

        def __init__(self, borgtype=None):
            """Class initialiser. Overwrite our class dictionary with the shared
            state. This makes us identical to every other instance of this class
            type."""
            if borgtype is None:
                raise TypeError('Borg::__init__: You must pass a borgtype')
            if not self.__shared_state.has_key(borgtype):
                dbg('Borg::__init__: Preparing borg state for %s' % borgtype)
                self.__shared_state[borgtype] = {}
            self.__dict__ = self.__shared_state[borgtype]

        def prepare_attributes(self):
            """This should be used to prepare any attributes of the borg class."""
            raise NotImplementedError('prepare_attributes')