virt-manager/virtManager/baseclass.py

# Copyright (C) 2010, 2013 Red Hat, Inc.
# Copyright (C) 2010 Cole Robinson <crobinso@redhat.com>
#
# This work is licensed under the GNU GPLv2 or later.
# See the COPYING file in the top-level directory.

import os
import sys
import threading
import traceback
import types

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

from virtinst import log

from . import config


class vmmGObject(GObject.GObject):
    # Objects can set this to false to disable leak tracking
    _leak_check = True

    # Singleton reference, if applicable (vmmSystray, vmmInspection, ...)
    _instance = None

    # windowlist mapping, if applicable (vmmVMWindow, vmmHost, ...)
    _instances = None

    # This saves a bunch of imports and typing
    RUN_FIRST = GObject.SignalFlags.RUN_FIRST

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

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

        self.__cleaned_up = False

        self._gobject_handles = []
        self._gobject_handles_map = {}
        self._gobject_timeouts = []
        self._gsettings_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 config.vmmConfig.is_initialized() and self._leak_check:
            self.config.add_object(self.object_key)

    def _get_err(self):
        from . import error
        return error.vmmErrorDialog.get_instance()
    err = property(_get_err)

    def cleanup(self):
        if self.__cleaned_up:
            return

        # Do any cleanup required to drop reference counts so object is
        # actually reaped by python. Usually means unregistering callbacks
        try:
            # pylint: disable=protected-access
            if self.__class__._instance == self:
                # We set this to True which can help us catch instances
                # where cleanup routines try to reinit singleton classes
                self.__class__._instance = True

            _instances = self.__class__._instances or {}
            for k, v in list(_instances.items()):
                if v == self:
                    _instances.pop(k)

            self._cleanup()

            for h in self._gsettings_handles[:]:
                self.remove_gsettings_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)
        except Exception:
            log.exception("Error cleaning up %s", self)

        self.__cleaned_up = True

    def _cleanup_on_app_close(self):
        from .engine import vmmEngine
        vmmEngine.get_instance().connect(
                "app-closing", lambda src: self.cleanup())

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

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

    @property
    def config(self):
        return config.vmmConfig.get_instance()


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

    def connect(self, name, callback, *args):
        """
        GObject connect() wrapper to simplify callers, and track handles
        for easy cleanup
        """
        ret = GObject.GObject.connect(self, name, callback, *args)

        # If the passed callback is a method of a class instance,
        # keep a mapping of id(instance):[handles]. This lets us
        # implement disconnect_by_obj to simplify signal removal
        if isinstance(callback, types.MethodType):
            i = id(callback.__self__)
            if i not in self._gobject_handles_map:
                self._gobject_handles_map[i] = []
            self._gobject_handles_map[i].append(ret)

        self._gobject_handles.append(ret)
        return ret

    def disconnect(self, handle):
        """
        GObject disconnect() wrapper to simplify callers
        """
        ret = GObject.GObject.disconnect(self, handle)
        self._gobject_handles.remove(handle)
        return ret

    def disconnect_by_obj(self, instance):
        """
        disconnect() every signal attached to a method of the passed instance
        """
        i = id(instance)
        for handle in self._gobject_handles_map.get(i, []):
            if handle in self._gobject_handles:
                self.disconnect(handle)
        self._gobject_handles_map.pop(i, None)

    def timeout_add(self, timeout, func, *args):
        """
        GLib timeout_add wrapper to simplify callers, and track handles
        for easy cleanup
        """
        ret = GLib.timeout_add(timeout, func, *args)
        self.add_gobject_timeout(ret)
        return ret

    def emit(self, signal_name, *args):
        """
        GObject emit() wrapper to simplify callers
        """
        if not self._is_main_thread():
            log.error("emitting signal from non-main thread. This is a bug "
                    "please report it. thread=%s self=%s signal=%s",
                    self._thread_name(), self, signal_name)
        return GObject.GObject.emit(self, signal_name, *args)

    def add_gsettings_handle(self, handle):
        self._gsettings_handles.append(handle)
    def remove_gsettings_handle(self, handle):
        self.config.remove_notifier(handle)
        self._gsettings_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 _refcount(self):
        return sys.getrefcount(self)

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

    def _gc_get_referrers(self):
        import gc
        import pprint
        pprint.pprint(gc.get_referrers(self))

    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 _thread_name(self):
        return threading.current_thread().name

    def _is_main_thread(self):
        return self._thread_name() == "MainThread"


    ##############################
    # Custom signal/idle helpers #
    ##############################

    def connect_once(self, signal, func, *args):
        """
        Like standard glib connect(), but only runs the signal handler
        once, then unregisters it
        """
        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):
        """
        Like standard glib connect(), but allows the signal handler to
        unregister itself if it returns True
        """
        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)


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

        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_file(uifile)

            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 . 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):
        if self.__cleaned_up:
            return

        try:
            self.close()
            vmmGObject.cleanup(self)
            self.builder = None
            if not self._external_topwin:
                self.topwin.destroy()
            self.topwin = None
            self._err = None
        except Exception:
            log.exception("Error cleaning up %s", self)

        self.__cleaned_up = True

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

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

    def is_visible(self):
        return bool(self.topwin and self.topwin.get_visible())

    def bind_escape_key_close(self):
        def close_on_escape(src_ignore, event):
            if Gdk.keyval_name(event.keyval) == "Escape":
                self.close()
        self.topwin.connect("key-press-event", close_on_escape)

    def _set_cursor(self, cursor_type):
        gdk_window = self.topwin.get_window()
        if not gdk_window:
            return

        try:
            cursor = Gdk.Cursor.new_from_name(
                    gdk_window.get_display(), cursor_type)
            gdk_window.set_cursor(cursor)
        except Exception:
            # If a cursor icon theme isn't installed this can cause errors
            # https://bugzilla.redhat.com/show_bug.cgi?id=1516588
            log.debug("Error setting cursor_type=%s",
                    cursor_type, exc_info=True)

    def set_finish_cursor(self):
        self.topwin.set_sensitive(False)
        self._set_cursor("progress")

    def reset_finish_cursor(self, topwin=None):
        if not topwin:
            topwin = self.topwin
        topwin.set_sensitive(True)
        self._set_cursor("default")

    def _cleanup_on_conn_removed(self):
        from .connmanager import vmmConnectionManager
        connmanager = vmmConnectionManager.get_instance()

        def _cb(_src, uri):
            _conn = getattr(self, "conn", None)
            if _conn and _conn.get_uri() == uri:
                self.cleanup()
                return True
        connmanager.connect_opt_out("conn-removed", _cb)