virt-manager/virtManager/baseclass.py

#
# Copyright (C) 2010, 2013 Red Hat, Inc.
# Copyright (C) 2010 Cole Robinson <crobinso@redhat.com>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
# MA 02110-1301 USA.
#

import logging
import os
import sys
import threading
import traceback

from virtManager import config

from gi.repository import Gdk
from gi.repository import GLib
from gi.repository import GObject
from gi.repository import Gtk


class vmmGObject(GObject.GObject):
    _leak_check = True

    @staticmethod
    def idle_add(func, *args, **kwargs):
        """
        Make sure idle functions are run thread safe
        """
        def cb():
            try:
                return func(*args, **kwargs)
            except:
                print traceback.format_exc()
            return False
        return GLib.idle_add(cb)

    def __init__(self):
        GObject.GObject.__init__(self)
        self.config = config.running_config

        self._gobject_handles = []
        self._gobject_timeouts = []
        self._gconf_handles = []

        self._signal_id_map = {}
        self._next_signal_id = 1

        self.object_key = str(self)

        # Config might not be available if we error early in startup
        if self.config and self._leak_check:
            self.config.add_object(self.object_key)

    def cleanup(self):
        # Do any cleanup required to drop reference counts so object is
        # actually reaped by python. Usually means unregistering callbacks
        try:
            for h in self._gconf_handles[:]:
                self.remove_gconf_handle(h)
            for h in self._gobject_handles[:]:
                if GObject.GObject.handler_is_connected(self, h):
                    self.disconnect(h)
            for h in self._gobject_timeouts[:]:
                self.remove_gobject_timeout(h)

            self._cleanup()
        except:
            logging.exception("Error cleaning up %s", self)

    def _cleanup(self):
        raise NotImplementedError("_cleanup must be implemented in subclass")

    # pylint: disable=arguments-differ
    # Newer pylint can detect, but warns that overridden arguments are wrong

    def connect(self, name, callback, *args):
        ret = GObject.GObject.connect(self, name, callback, *args)
        self._gobject_handles.append(ret)
        return ret

    def disconnect(self, handle):
        ret = GObject.GObject.disconnect(self, handle)
        self._gobject_handles.remove(handle)
        return ret

    def add_gconf_handle(self, handle):
        self._gconf_handles.append(handle)
    def remove_gconf_handle(self, handle):
        self.config.remove_notifier(handle)
        self._gconf_handles.remove(handle)

    def add_gobject_timeout(self, handle):
        self._gobject_timeouts.append(handle)
    def remove_gobject_timeout(self, handle):
        GLib.source_remove(handle)
        self._gobject_timeouts.remove(handle)

    def _logtrace(self, msg=""):
        if msg:
            msg += " "
        logging.debug("%s(%s %s)\n:%s",
                      msg, self.object_key, self._refcount(),
                       "".join(traceback.format_stack()))

    def _refcount(self):
        # Function generates 2 temporary refs, so adjust total accordingly
        return (sys.getrefcount(self) - 2)

    def _start_thread(self, target=None, name=None, args=None, kwargs=None):
        # Helper for starting a daemonized thread
        t = threading.Thread(target=target, name=name,
            args=args or [], kwargs=kwargs or {})
        t.daemon = True
        t.start()

    def connect_once(self, signal, func, *args):
        id_list = []

        def wrap_func(*wrapargs):
            if id_list:
                self.disconnect(id_list[0])

            return func(*wrapargs)

        conn_id = self.connect(signal, wrap_func, *args)
        id_list.append(conn_id)

        return conn_id

    def connect_opt_out(self, signal, func, *args):
        id_list = []

        def wrap_func(*wrapargs):
            ret = func(*wrapargs)
            if ret and id_list:
                self.disconnect(id_list[0])

        conn_id = self.connect(signal, wrap_func, *args)
        id_list.append(conn_id)

        return conn_id

    def idle_emit(self, signal, *args):
        """
        Safe wrapper for using 'self.emit' with GLib.idle_add
        """
        def emitwrap(_s, *_a):
            self.emit(_s, *_a)
            return False

        self.idle_add(emitwrap, signal, *args)

    def timeout_add(self, timeout, func, *args):
        """
        Make sure timeout functions are run thread safe
        """
        def cb():
            try:
                return func(*args)
            except:
                print traceback.format_exc()
            return False
        ret = GLib.timeout_add(timeout, cb)
        self.add_gobject_timeout(ret)
        return ret

    def emit(self, signal_name, *args):
        return GObject.GObject.emit(self, signal_name, *args)

    def __del__(self):
        try:
            if self.config and self._leak_check:
                self.config.remove_object(self.object_key)
        except:
            logging.exception("Error removing %s", self.object_key)


class vmmGObjectUI(vmmGObject):
    @staticmethod
    def bind_escape_key_close_helper(topwin, close_cb):
        def close_on_escape(src_ignore, event):
            if Gdk.keyval_name(event.keyval) == "Escape":
                close_cb()
        topwin.connect("key-press-event", close_on_escape)

    def __init__(self, filename, windowname, builder=None, topwin=None):
        vmmGObject.__init__(self)
        self._external_topwin = bool(topwin)

        if filename:
            uifile = os.path.join(self.config.get_ui_dir(), filename)

            self.builder = Gtk.Builder()
            self.builder.set_translation_domain("virt-manager")
            self.builder.add_from_string(file(uifile).read())

            if not topwin:
                self.topwin = self.widget(windowname)
                self.topwin.hide()
            else:
                self.topwin = topwin
        else:
            self.builder = builder
            self.topwin = topwin

        self._err = None

    def _get_err(self):
        if self._err is None:
            from virtManager import error
            self._err = error.vmmErrorDialog(self.topwin)
        return self._err
    err = property(_get_err)

    def widget(self, name):
        return self.builder.get_object(name)

    def cleanup(self):
        self.close()
        vmmGObject.cleanup(self)
        self.builder = None
        if not self._external_topwin:
            self.topwin.destroy()
        self.topwin = None
        self._err = None

    def _cleanup(self):
        raise NotImplementedError("_cleanup must be implemented in subclass")

    def close(self, ignore1=None, ignore2=None):
        pass

    def bind_escape_key_close(self):
        self.bind_escape_key_close_helper(self.topwin, self.close)