1# vim: ft=python fileencoding=utf-8 sts=4 sw=4 et:
2
3# Copyright 2017-2021 Florian Bruhin (The Compiler) <mail@qutebrowser.org>
4#
5# This file is part of qutebrowser.
6#
7# qutebrowser is free software: you can redistribute it and/or modify
8# it under the terms of the GNU General Public License as published by
9# the Free Software Foundation, either version 3 of the License, or
10# (at your option) any later version.
11#
12# qutebrowser is distributed in the hope that it will be useful,
13# but WITHOUT ANY WARRANTY; without even the implied warranty of
14# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15# GNU General Public License for more details.
16#
17# You should have received a copy of the GNU General Public License
18# along with qutebrowser.  If not, see <https://www.gnu.org/licenses/>.
19
20"""Navigation (back/forward) indicator displayed in the statusbar."""
21
22from qutebrowser.mainwindow.statusbar import textbase
23
24
25class Backforward(textbase.TextBase):
26
27    """Shows navigation indicator (if you can go backward and/or forward)."""
28
29    def __init__(self, parent=None):
30        super().__init__(parent)
31        self.enabled = False
32
33    def on_tab_cur_url_changed(self, tabs):
34        """Called on URL changes."""
35        tab = tabs.widget.currentWidget()
36        if tab is None:  # pragma: no cover
37            self.setText('')
38            self.hide()
39            return
40        self.on_tab_changed(tab)
41
42    def on_tab_changed(self, tab):
43        """Update the text based on the given tab."""
44        text = ''
45        if tab.history.can_go_back():
46            text += '<'
47        if tab.history.can_go_forward():
48            text += '>'
49        if text:
50            text = '[' + text + ']'
51        self.setText(text)
52        self.setVisible(bool(text) and self.enabled)
53