path: root/ranger/ext/accumulator.py

# This file is part of ranger, the console file manager.
# License: GNU GPL version 3, see the file "AUTHORS" for details.

from __future__ import (absolute_import, division, print_function)

from ranger.ext.direction import Direction


class Accumulator(object):

    def __init__(self):
        self.pointer = 0
        self.pointed_obj = None

    def move(self, narg=None, **keywords):
        direction = Direction(keywords)
        lst = self.get_list()
        if not lst:
            return self.pointer
        pointer = direction.move(
            direction=direction.down(),
            maximum=len(lst),
            override=narg,
            pagesize=self.get_height(),
            current=self.pointer)
        self.pointer = pointer
        self.correct_pointer()
        return pointer

    def move_to_obj(self, arg, attr=None):
        if not arg:
            return None

        lst = self.get_list()

        if not lst:
            return None

        do_get_attr = isinstance(attr, str)

        good = arg
        if do_get_attr:
            try:
                good = getattr(arg, attr)
            except (TypeError, AttributeError):
                pass

        for obj, i in zip(lst, range(len(lst))):
            if do_get_attr:
                try:
                    test = getattr(obj, attr)
                except AttributeError:
                    continue
            else:
                test = obj

            if test == good:
                self.move(to=i)
                return True

        return self.move(to=self.pointer)

    # XXX Is this still necessary?  move() ensures correct pointer position
    def correct_pointer(self):
        lst = self.get_list()

        if not lst:
            self.pointer = 0
            self.pointed_obj = None

        else:
            i = self.pointer

            if i is None:
                i = 0
            if i >= len(lst):
                i = len(lst) - 1
            i = max(0, i)

            self.pointer = i
            self.pointed_obj = lst[i]

    def pointer_is_synced(self):
        lst = self.get_list()
        try:
            return lst[self.pointer] == self.pointed_obj
        except (IndexError, KeyError):
            return False

    def sync_index(self, **kw):
        self.move_to_obj(self.pointed_obj, **kw)

    @staticmethod
    def get_list():
        """OVERRIDE THIS"""
        return []

    @staticmethod
    def get_height():
        """OVERRIDE THIS"""
        return 25