indent-converter.py

# -*- coding: utf-8 -*-
from gi.repository import GObject, Gedit, Gtk, Gio
from gettext import gettext as _
import re


UI_XML = """<ui>
    <menubar name='MenuBar'>
        <menu name='EditMenu' action='Edit'>
            <placeholder name='EditOps_6'>
                <menu action='TabConvert'>
                    <menuitem action='SpacesToTabs'/>
                    <menuitem action='TabsToSpaces'/>
                </menu>
            </placeholder>
        </menu>
    </menubar>
</ui>"""


class IndentConverterPlugin(GObject.Object, Gedit.WindowActivatable):

    __gtype_name__ = "IndentConverterPlugin"

    window = GObject.property(type=Gedit.Window)

    def __init__(self):
        GObject.Object.__init__(self)

    def do_activate(self):
        self.insert_menu()

    def do_deactivate(self):
        self.remove_menu()

    def do_update_state(self):
        view = self.window.get_active_view()
        self.action_group.set_sensitive(bool(view and view.get_editable()))

    def tab_size(self):
        settings = Gio.Settings.new('org.gnome.gedit.preferences.editor')
        tab_size = settings.get_uint('tabs-size')
        return tab_size

    def insert_menu(self):
        manager = self.window.get_ui_manager()
        self.action_group = Gtk.ActionGroup('IndentConverterActions')
        self.action_group.add_actions([
            ('TabConvert', None, _('Convert Tabs'), None, None, None),
            ('SpacesToTabs', Gtk.STOCK_INDENT, _('Convert spaces to tabs'),
                None, _('Convert spaces to tabs'), self.do_spaces_to_tabs),
            ('TabsToSpaces', Gtk.STOCK_INDENT, _('Convert tabs to spaces'),
                None, _('Convert tabs to spaces'), self.do_tabs_to_spaces),
        ])
        manager.insert_action_group(self.action_group, -1)
        self.ui_id = manager.add_ui_from_string(UI_XML)

    def remove_menu(self):
        manager = self.window.get_ui_manager()
        manager.remove_ui(self.ui_id)
        manager.remove_action_group(self.action_group)
        manager.ensure_update()

    def guess_tab_size(self, text):
        def gcd(a, b):
            return a if b == 0 else gcd(b, a % b);

        r = re.compile('^ +', re.MULTILINE)
        matches = r.findall(text)
        freq = {}

        # `key` - length of leading spaces, `value` - it's frequency
        for spaces in matches:
            spaces = len(spaces)
            if spaces in freq:
                freq[spaces] += 1
            else:
                freq[spaces] = 1

        # sort frequencies by value:
        items = [ [i[1], i[0]] for i in freq.items() ]
        items.sort()
        items.reverse()
        items = [i[1] for i in items]

        if len(items) == 0:
            return 0
        elif len(items) == 1:
            return items[0]
        else:
            return gcd(items[0], items[1])

    def do_spaces_to_tabs(self, action):
        doc = self.window.get_active_document()
        start, end = doc.get_bounds()
        text = doc.get_text(start, end, True)

        tab_size = self.guess_tab_size(text)
        if (tab_size < 2):
            tab_size = self.tab_size()
        r = re.compile('^(?:' +  (' ' * tab_size) + ')+', re.MULTILINE)

        def replacer(match):
            return '\t' * (len(match.group(0)) / tab_size)

        text = r.sub(replacer, text)

        doc.begin_user_action()
        doc.set_text(text)
        doc.end_user_action()

    def do_tabs_to_spaces(self, action):
        doc = self.window.get_active_document()
        start, end = doc.get_bounds()
        text = doc.get_text(start, end, True)
        text = text.expandtabs(self.tab_size())

        doc.begin_user_action()
        doc.set_text(text)
        doc.end_user_action()