Class BoundedSet

praw/models/util.py:14–40

A set with a maximum size that evicts the oldest items when necessary. This class does not implement the complete set interface.

class BoundedSet:
    """A set with a maximum size that evicts the oldest items when necessary.

    This class does not implement the complete set interface.

    """

    def __contains__(self, item: Any) -> bool:
        """Test if the :class:`.BoundedSet` contains item."""
        self._access(item)
        return item in self._set

    def __init__(self, max_items: int) -> None:
        """Initialize a :class:`.BoundedSet` instance."""
        self.max_items = max_items
        self._set = OrderedDict()

    def _access(self, item: Any) -> None:
        if item in self._set:
            self._set.move_to_end(item)

    def add(self, item: Any) -> None:
        """Add an item to the set discarding the oldest item if necessary."""
        self._access(item)
        self._set[item] = None
        if len(self._set) > self.max_items:
            self._set.popitem(last=False)


class ExponentialCounter: