stop channels in background threads

stop_channels() *must* be called, to prevent fd count rising, but
stop_channels waits up to 0.2s up to 4 times, and it shouldn't get in the
way of the UI.  This just calls stop_channels in a thread, to protect
UI responsiveness.

IPython/frontend/qt/console/mainwindow.py

@@ -1,829 +1,839 b''
 """The Qt MainWindow for the QtConsole
 
 This is a tabbed pseudo-terminal of IPython sessions, with a menu bar for
 common actions.
 
 Authors:
 
 * Evan Patterson
 * Min RK
 * Erik Tollerud
 * Fernando Perez
 * Bussonnier Matthias
 * Thomas Kluyver
 
 """
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 # stdlib imports
 import sys
 import webbrowser
+from threading import Thread
 
 # System library imports
 from IPython.external.qt import QtGui,QtCore
 
+def background(f):
+    """call a function in a simple thread, to prevent blocking"""
+    t = Thread(target=f)
+    t.start()
+    return t
+
 #-----------------------------------------------------------------------------
 # Classes
 #-----------------------------------------------------------------------------
 
 class MainWindow(QtGui.QMainWindow):
 
     #---------------------------------------------------------------------------
     # 'object' interface
     #---------------------------------------------------------------------------
 
     def __init__(self, app,
                     confirm_exit=True,
                     new_frontend_factory=None, slave_frontend_factory=None,
                 ):
         """ Create a tabbed MainWindow for managing IPython FrontendWidgets
         
         Parameters
         ----------
         
         app : reference to QApplication parent
         confirm_exit : bool, optional
             Whether we should prompt on close of tabs
         new_frontend_factory : callable
             A callable that returns a new IPythonWidget instance, attached to
             its own running kernel.
         slave_frontend_factory : callable
             A callable that takes an existing IPythonWidget, and  returns a new 
             IPythonWidget instance, attached to the same kernel.
         """
 
         super(MainWindow, self).__init__()
         self._app = app
         self.confirm_exit = confirm_exit
         self.new_frontend_factory = new_frontend_factory
         self.slave_frontend_factory = slave_frontend_factory
 
         self.tab_widget = QtGui.QTabWidget(self)
         self.tab_widget.setDocumentMode(True)
         self.tab_widget.setTabsClosable(True)
         self.tab_widget.tabCloseRequested[int].connect(self.close_tab)
 
         self.setCentralWidget(self.tab_widget)
         # hide tab bar at first, since we have no tabs:
         self.tab_widget.tabBar().setVisible(False)
         # prevent focus in tab bar
         self.tab_widget.setFocusPolicy(QtCore.Qt.NoFocus)
 
     def update_tab_bar_visibility(self):
         """ update visibility of the tabBar depending of the number of tab
 
         0 or 1 tab, tabBar hidden
         2+ tabs, tabBar visible
 
         send a self.close if number of tab ==0
 
         need to be called explicitely, or be connected to tabInserted/tabRemoved
         """
         if self.tab_widget.count() <= 1:
             self.tab_widget.tabBar().setVisible(False)
         else:
             self.tab_widget.tabBar().setVisible(True)
         if self.tab_widget.count()==0 :
             self.close()
 
     @property
     def active_frontend(self):
         return self.tab_widget.currentWidget()
     
     def create_tab_with_new_frontend(self):
         """create a new frontend and attach it to a new tab"""
         widget = self.new_frontend_factory()
         self.add_tab_with_frontend(widget)
     
     def create_tab_with_current_kernel(self):
         """create a new frontend attached to the same kernel as the current tab"""
         current_widget = self.tab_widget.currentWidget()
         current_widget_index = self.tab_widget.indexOf(current_widget)
         current_widget_name = self.tab_widget.tabText(current_widget_index)
         widget = self.slave_frontend_factory(current_widget)
         if 'slave' in current_widget_name:
             # don't keep stacking slaves
             name = current_widget_name
         else:
             name = str('('+current_widget_name+') slave')
         self.add_tab_with_frontend(widget,name=name)
 
     def close_tab(self,current_tab):
         """ Called when you need to try to close a tab.
 
         It takes the number of the tab to be closed as argument, or a referece
         to the wiget insite this tab
         """
 
         # let's be sure "tab" and "closing widget are respectivey the index of the tab to close
         # and a reference to the trontend to close
         if type(current_tab) is not int :
             current_tab = self.tab_widget.indexOf(current_tab)
         closing_widget=self.tab_widget.widget(current_tab)
 
 
         # when trying to be closed, widget might re-send a request to be closed again, but will
         # be deleted when event will be processed. So need to check that widget still exist and
         # skip if not. One example of this is when 'exit' is send in a slave tab. 'exit' will be
         # re-send by this fonction on the master widget, which ask all slaves widget to exit
         if closing_widget==None:
             return
 
         #get a list of all slave widgets on the same kernel.
         slave_tabs = self.find_slave_widgets(closing_widget)
 
         keepkernel = None #Use the prompt by default
         if hasattr(closing_widget,'_keep_kernel_on_exit'): #set by exit magic
             keepkernel = closing_widget._keep_kernel_on_exit
             # If signal sent by exit magic (_keep_kernel_on_exit, exist and not None)
             # we set local slave tabs._hidden to True to avoid prompting for kernel
             # restart when they get the signal. and then "forward" the 'exit'
             # to the main window
             if keepkernel is not None:
                 for tab in slave_tabs:
                     tab._hidden = True
                 if closing_widget in slave_tabs:
                     try :
                         self.find_master_tab(closing_widget).execute('exit')
                     except AttributeError:
                         self.log.info("Master already closed or not local, closing only current tab")
                         self.tab_widget.removeTab(current_tab)
                     self.update_tab_bar_visibility()
                     return
 
         kernel_manager = closing_widget.kernel_manager
 
         if keepkernel is None and not closing_widget._confirm_exit:
             # don't prompt, just terminate the kernel if we own it
             # or leave it alone if we don't
             keepkernel = closing_widget._existing
         if keepkernel is None: #show prompt
             if kernel_manager and kernel_manager.channels_running:
                 title = self.window().windowTitle()
                 cancel = QtGui.QMessageBox.Cancel
                 okay = QtGui.QMessageBox.Ok
                 if closing_widget._may_close:
                     msg = "You are closing the tab : "+'"'+self.tab_widget.tabText(current_tab)+'"'
                     info = "Would you like to quit the Kernel and close all attached Consoles as well?"
                     justthis = QtGui.QPushButton("&No, just this Tab", self)
                     justthis.setShortcut('N')
                     closeall = QtGui.QPushButton("&Yes, close all", self)
                     closeall.setShortcut('Y')
                     box = QtGui.QMessageBox(QtGui.QMessageBox.Question,
                                             title, msg)
                     box.setInformativeText(info)
                     box.addButton(cancel)
                     box.addButton(justthis, QtGui.QMessageBox.NoRole)
                     box.addButton(closeall, QtGui.QMessageBox.YesRole)
                     box.setDefaultButton(closeall)
                     box.setEscapeButton(cancel)
                     pixmap = QtGui.QPixmap(self._app.icon.pixmap(QtCore.QSize(64,64)))
                     box.setIconPixmap(pixmap)
                     reply = box.exec_()
                     if reply == 1: # close All
                         for slave in slave_tabs:
+                            background(slave.kernel_manager.stop_channels)
                             self.tab_widget.removeTab(self.tab_widget.indexOf(slave))
                         closing_widget.execute("exit")
                         self.tab_widget.removeTab(current_tab)
+                        background(kernel_manager.stop_channels)
                     elif reply == 0: # close Console
                         if not closing_widget._existing:
                             # Have kernel: don't quit, just close the tab
                             closing_widget.execute("exit True")
                         self.tab_widget.removeTab(current_tab)
+                        background(kernel_manager.stop_channels)
                 else:
                     reply = QtGui.QMessageBox.question(self, title,
                         "Are you sure you want to close this Console?"+
                         "\nThe Kernel and other Consoles will remain active.",
                         okay|cancel,
                         defaultButton=okay
                         )
                     if reply == okay:
                         self.tab_widget.removeTab(current_tab)
         elif keepkernel: #close console but leave kernel running (no prompt)
             self.tab_widget.removeTab(current_tab)
-            if kernel_manager and kernel_manager.channels_running:
-                kernel_manager.stop_channels()
+            background(kernel_manager.stop_channels)
         else: #close console and kernel (no prompt)
             self.tab_widget.removeTab(current_tab)
             if kernel_manager and kernel_manager.channels_running:
-                kernel_manager.shutdown_kernel()
                 for slave in slave_tabs:
-                    slave.kernel_manager.stop_channels()
+                    background(slave.kernel_manager.stop_channels)
                     self.tab_widget.removeTab(self.tab_widget.indexOf(slave))
+                kernel_manager.shutdown_kernel()
+                background(kernel_manager.stop_channels)
         
         self.update_tab_bar_visibility()
 
     def add_tab_with_frontend(self,frontend,name=None):
         """ insert a tab with a given frontend in the tab bar, and give it a name
 
         """
         if not name:
             name=str('kernel '+str(self.tab_widget.count()))
         self.tab_widget.addTab(frontend,name)
         self.update_tab_bar_visibility()
         self.make_frontend_visible(frontend)
         frontend.exit_requested.connect(self.close_tab)
 
     def next_tab(self):
         self.tab_widget.setCurrentIndex((self.tab_widget.currentIndex()+1))
 
     def prev_tab(self):
         self.tab_widget.setCurrentIndex((self.tab_widget.currentIndex()-1))
 
     def make_frontend_visible(self,frontend):
         widget_index=self.tab_widget.indexOf(frontend)
         if widget_index > 0 :
             self.tab_widget.setCurrentIndex(widget_index)
 
     def find_master_tab(self,tab,as_list=False):
         """
         Try to return the frontend that own the kernel attached to the given widget/tab.
 
             Only find frontend owed by the current application. Selection
             based on port of the kernel, might be inacurate if several kernel
             on different ip use same port number.
 
             This fonction does the conversion tabNumber/widget if needed.
             Might return None if no master widget (non local kernel)
             Will crash IPython if more than 1 masterWidget
 
             When asList set to True, always return a list of widget(s) owning
             the kernel. The list might be empty or containing several Widget.
         """
 
         #convert from/to int/richIpythonWidget if needed
         if isinstance(tab, int):
             tab = self.tab_widget.widget(tab)
         km=tab.kernel_manager
 
         #build list of all widgets
         widget_list = [self.tab_widget.widget(i) for i in range(self.tab_widget.count())]
 
         # widget that are candidate to be the owner of the kernel does have all the same port of the curent widget
         # And should have a _may_close attribute
         filtered_widget_list = [ widget for widget in widget_list if
                                 widget.kernel_manager.connection_file == km.connection_file and
                                 hasattr(widget,'_may_close') ]
         # the master widget is the one that may close the kernel
         master_widget= [ widget for widget in filtered_widget_list if widget._may_close]
         if as_list:
             return master_widget
         assert(len(master_widget)<=1 )
         if len(master_widget)==0:
             return None
 
         return master_widget[0]
 
     def find_slave_widgets(self,tab):
         """return all the frontends that do not own the kernel attached to the given widget/tab.
 
             Only find frontends owned by the current application. Selection
             based on connection file of the kernel.
 
             This function does the conversion tabNumber/widget if needed.
         """
         #convert from/to int/richIpythonWidget if needed
         if isinstance(tab, int):
             tab = self.tab_widget.widget(tab)
         km=tab.kernel_manager
 
         #build list of all widgets
         widget_list = [self.tab_widget.widget(i) for i in range(self.tab_widget.count())]
 
         # widget that are candidate not to be the owner of the kernel does have all the same port of the curent widget
         filtered_widget_list = ( widget for widget in widget_list if
                                 widget.kernel_manager.connection_file == km.connection_file)
         # Get a list of all widget owning the same kernel and removed it from
         # the previous cadidate. (better using sets ?)
         master_widget_list = self.find_master_tab(tab, as_list=True)
         slave_list = [widget for widget in filtered_widget_list if widget not in master_widget_list]
 
         return slave_list
 
     # Populate the menu bar with common actions and shortcuts
     def add_menu_action(self, menu, action, defer_shortcut=False):
         """Add action to menu as well as self
         
         So that when the menu bar is invisible, its actions are still available.
         
         If defer_shortcut is True, set the shortcut context to widget-only,
         where it will avoid conflict with shortcuts already bound to the
         widgets themselves.
         """
         menu.addAction(action)
         self.addAction(action)
 
         if defer_shortcut:
             action.setShortcutContext(QtCore.Qt.WidgetShortcut)
     
     def init_menu_bar(self):
         #create menu in the order they should appear in the menu bar
         self.init_file_menu()
         self.init_edit_menu()
         self.init_view_menu()
         self.init_kernel_menu()
         self.init_magic_menu()
         self.init_window_menu()
         self.init_help_menu()
     
     def init_file_menu(self):
         self.file_menu = self.menuBar().addMenu("&File")
         
         self.new_kernel_tab_act = QtGui.QAction("New Tab with &New kernel",
             self,
             shortcut="Ctrl+T",
             triggered=self.create_tab_with_new_frontend)
         self.add_menu_action(self.file_menu, self.new_kernel_tab_act)
 
         self.slave_kernel_tab_act = QtGui.QAction("New Tab with Sa&me kernel",
             self,
             shortcut="Ctrl+Shift+T",
             triggered=self.create_tab_with_current_kernel)
         self.add_menu_action(self.file_menu, self.slave_kernel_tab_act)
         
         self.file_menu.addSeparator()
 
         self.close_action=QtGui.QAction("&Close Tab",
             self,
             shortcut=QtGui.QKeySequence.Close,
             triggered=self.close_active_frontend
             )
         self.add_menu_action(self.file_menu, self.close_action)
 
         self.export_action=QtGui.QAction("&Save to HTML/XHTML",
             self,
             shortcut=QtGui.QKeySequence.Save,
             triggered=self.export_action_active_frontend
             )
         self.add_menu_action(self.file_menu, self.export_action, True)
 
         self.file_menu.addSeparator()
         
         printkey = QtGui.QKeySequence(QtGui.QKeySequence.Print)
         if printkey.matches("Ctrl+P") and sys.platform != 'darwin':
             # Only override the default if there is a collision.
             # Qt ctrl = cmd on OSX, so the match gets a false positive on OSX.
             printkey = "Ctrl+Shift+P"
         self.print_action = QtGui.QAction("&Print",
             self,
             shortcut=printkey,
             triggered=self.print_action_active_frontend)
         self.add_menu_action(self.file_menu, self.print_action, True)
         
         if sys.platform != 'darwin':
             # OSX always has Quit in the Application menu, only add it
             # to the File menu elsewhere.
 
             self.file_menu.addSeparator()
 
             self.quit_action = QtGui.QAction("&Quit",
                 self,
                 shortcut=QtGui.QKeySequence.Quit,
                 triggered=self.close,
             )
             self.add_menu_action(self.file_menu, self.quit_action)
 
     
     def init_edit_menu(self):
         self.edit_menu = self.menuBar().addMenu("&Edit")
         
         self.undo_action = QtGui.QAction("&Undo",
             self,
             shortcut=QtGui.QKeySequence.Undo,
             statusTip="Undo last action if possible",
             triggered=self.undo_active_frontend
             )
         self.add_menu_action(self.edit_menu, self.undo_action)
 
         self.redo_action = QtGui.QAction("&Redo",
             self,
             shortcut=QtGui.QKeySequence.Redo,
             statusTip="Redo last action if possible",
             triggered=self.redo_active_frontend)
         self.add_menu_action(self.edit_menu, self.redo_action)
 
         self.edit_menu.addSeparator()
 
         self.cut_action = QtGui.QAction("&Cut",
             self,
             shortcut=QtGui.QKeySequence.Cut,
             triggered=self.cut_active_frontend
             )
         self.add_menu_action(self.edit_menu, self.cut_action, True)
 
         self.copy_action = QtGui.QAction("&Copy",
             self,
             shortcut=QtGui.QKeySequence.Copy,
             triggered=self.copy_active_frontend
             )
         self.add_menu_action(self.edit_menu, self.copy_action, True)
 
         self.copy_raw_action = QtGui.QAction("Copy (&Raw Text)",
             self,
             shortcut="Ctrl+Shift+C",
             triggered=self.copy_raw_active_frontend
             )
         self.add_menu_action(self.edit_menu, self.copy_raw_action, True)
 
         self.paste_action = QtGui.QAction("&Paste",
             self,
             shortcut=QtGui.QKeySequence.Paste,
             triggered=self.paste_active_frontend
             )
         self.add_menu_action(self.edit_menu, self.paste_action, True)
 
         self.edit_menu.addSeparator()
         
         selectall = QtGui.QKeySequence(QtGui.QKeySequence.SelectAll)
         if selectall.matches("Ctrl+A") and sys.platform != 'darwin':
             # Only override the default if there is a collision.
             # Qt ctrl = cmd on OSX, so the match gets a false positive on OSX.
             selectall = "Ctrl+Shift+A"
         self.select_all_action = QtGui.QAction("Select &All",
             self,
             shortcut=selectall,
             triggered=self.select_all_active_frontend
             )
         self.add_menu_action(self.edit_menu, self.select_all_action, True)
 
     
     def init_view_menu(self):
         self.view_menu = self.menuBar().addMenu("&View")
 
         if sys.platform != 'darwin':
             # disable on OSX, where there is always a menu bar
             self.toggle_menu_bar_act = QtGui.QAction("Toggle &Menu Bar",
                 self,
                 shortcut="Ctrl+Shift+M",
                 statusTip="Toggle visibility of menubar",
                 triggered=self.toggle_menu_bar)
             self.add_menu_action(self.view_menu, self.toggle_menu_bar_act)
         
         fs_key = "Ctrl+Meta+F" if sys.platform == 'darwin' else "F11"
         self.full_screen_act = QtGui.QAction("&Full Screen",
             self,
             shortcut=fs_key,
             statusTip="Toggle between Fullscreen and Normal Size",
             triggered=self.toggleFullScreen)
         self.add_menu_action(self.view_menu, self.full_screen_act)
 
         self.view_menu.addSeparator()
 
         self.increase_font_size = QtGui.QAction("Zoom &In",
             self,
             shortcut=QtGui.QKeySequence.ZoomIn,
             triggered=self.increase_font_size_active_frontend
             )
         self.add_menu_action(self.view_menu, self.increase_font_size, True)
 
         self.decrease_font_size = QtGui.QAction("Zoom &Out",
             self,
             shortcut=QtGui.QKeySequence.ZoomOut,
             triggered=self.decrease_font_size_active_frontend
             )
         self.add_menu_action(self.view_menu, self.decrease_font_size, True)
 
         self.reset_font_size = QtGui.QAction("Zoom &Reset",
             self,
             shortcut="Ctrl+0",
             triggered=self.reset_font_size_active_frontend
             )
         self.add_menu_action(self.view_menu, self.reset_font_size, True)
 
         self.view_menu.addSeparator()
 
         self.clear_action = QtGui.QAction("&Clear Screen",
             self,
             shortcut='Ctrl+L',
             statusTip="Clear the console",
             triggered=self.clear_magic_active_frontend)
         self.add_menu_action(self.view_menu, self.clear_action)
     
     def init_kernel_menu(self):
         self.kernel_menu = self.menuBar().addMenu("&Kernel")
         # Qt on OSX maps Ctrl to Cmd, and Meta to Ctrl
         # keep the signal shortcuts to ctrl, rather than 
         # platform-default like we do elsewhere.
 
         ctrl = "Meta" if sys.platform == 'darwin' else "Ctrl"
 
         self.interrupt_kernel_action = QtGui.QAction("Interrupt current Kernel",
             self,
             triggered=self.interrupt_kernel_active_frontend,
             shortcut=ctrl+"+C",
             )
         self.add_menu_action(self.kernel_menu, self.interrupt_kernel_action)
 
         self.restart_kernel_action = QtGui.QAction("Restart current Kernel",
             self,
             triggered=self.restart_kernel_active_frontend,
             shortcut=ctrl+"+.",
             )
         self.add_menu_action(self.kernel_menu, self.restart_kernel_action)
 
         self.kernel_menu.addSeparator()
 
     def init_magic_menu(self):
         self.magic_menu = self.menuBar().addMenu("&Magic")
         self.all_magic_menu = self.magic_menu.addMenu("&All Magics")
         
         self.reset_action = QtGui.QAction("&Reset",
             self,
             statusTip="Clear all varible from workspace",
             triggered=self.reset_magic_active_frontend)
         self.add_menu_action(self.magic_menu, self.reset_action)
 
         self.history_action = QtGui.QAction("&History",
             self,
             statusTip="show command history",
             triggered=self.history_magic_active_frontend)
         self.add_menu_action(self.magic_menu, self.history_action)
 
         self.save_action = QtGui.QAction("E&xport History ",
             self,
             statusTip="Export History as Python File",
             triggered=self.save_magic_active_frontend)
         self.add_menu_action(self.magic_menu, self.save_action)
 
         self.who_action = QtGui.QAction("&Who",
             self,
             statusTip="List interactive variable",
             triggered=self.who_magic_active_frontend)
         self.add_menu_action(self.magic_menu, self.who_action)
 
         self.who_ls_action = QtGui.QAction("Wh&o ls",
             self,
             statusTip="Return a list of interactive variable",
             triggered=self.who_ls_magic_active_frontend)
         self.add_menu_action(self.magic_menu, self.who_ls_action)
 
         self.whos_action = QtGui.QAction("Who&s",
             self,
             statusTip="List interactive variable with detail",
             triggered=self.whos_magic_active_frontend)
         self.add_menu_action(self.magic_menu, self.whos_action)
         
         # allmagics submenu:
         
         #for now this is just a copy and paste, but we should get this dynamically
         magiclist=["%alias", "%autocall", "%automagic", "%bookmark", "%cd", "%clear",
             "%colors", "%debug", "%dhist", "%dirs", "%doctest_mode", "%ed", "%edit", "%env", "%gui",
             "%guiref", "%hist", "%history", "%install_default_config", "%install_profiles",
             "%less", "%load_ext", "%loadpy", "%logoff", "%logon", "%logstart", "%logstate",
             "%logstop", "%lsmagic", "%macro", "%magic", "%man", "%more", "%notebook", "%page",
             "%pastebin", "%pdb", "%pdef", "%pdoc", "%pfile", "%pinfo", "%pinfo2", "%popd", "%pprint",
             "%precision", "%profile", "%prun", "%psearch", "%psource", "%pushd", "%pwd", "%pycat",
             "%pylab", "%quickref", "%recall", "%rehashx", "%reload_ext", "%rep", "%rerun",
             "%reset", "%reset_selective", "%run", "%save", "%sc", "%sx", "%tb", "%time", "%timeit",
             "%unalias", "%unload_ext", "%who", "%who_ls", "%whos", "%xdel", "%xmode"]
 
         def make_dynamic_magic(i):
                 def inner_dynamic_magic():
                     self.active_frontend.execute(i)
                 inner_dynamic_magic.__name__ = "dynamics_magic_%s" % i
                 return inner_dynamic_magic
 
         for magic in magiclist:
             xaction = QtGui.QAction(magic,
                 self,
                 triggered=make_dynamic_magic(magic)
                 )
             self.all_magic_menu.addAction(xaction)
     
     def init_window_menu(self):
         self.window_menu = self.menuBar().addMenu("&Window")
         if sys.platform == 'darwin':
             # add min/maximize actions to OSX, which lacks default bindings.
             self.minimizeAct = QtGui.QAction("Mini&mize",
                 self,
                 shortcut="Ctrl+m",
                 statusTip="Minimize the window/Restore Normal Size",
                 triggered=self.toggleMinimized)
             # maximize is called 'Zoom' on OSX for some reason
             self.maximizeAct = QtGui.QAction("&Zoom",
                 self,
                 shortcut="Ctrl+Shift+M",
                 statusTip="Maximize the window/Restore Normal Size",
                 triggered=self.toggleMaximized)
 
             self.add_menu_action(self.window_menu, self.minimizeAct)
             self.add_menu_action(self.window_menu, self.maximizeAct)
             self.window_menu.addSeparator()
 
         prev_key = "Ctrl+Shift+Left" if sys.platform == 'darwin' else "Ctrl+PgUp"
         self.prev_tab_act = QtGui.QAction("Pre&vious Tab",
             self,
             shortcut=prev_key,
             statusTip="Select previous tab",
             triggered=self.prev_tab)
         self.add_menu_action(self.window_menu, self.prev_tab_act)
 
         next_key = "Ctrl+Shift+Right" if sys.platform == 'darwin' else "Ctrl+PgDown"
         self.next_tab_act = QtGui.QAction("Ne&xt Tab",
             self,
             shortcut=next_key,
             statusTip="Select next tab",
             triggered=self.next_tab)
         self.add_menu_action(self.window_menu, self.next_tab_act)
     
     def init_help_menu(self):
         # please keep the Help menu in Mac Os even if empty. It will
         # automatically contain a search field to search inside menus and
         # please keep it spelled in English, as long as Qt Doesn't support
         # a QAction.MenuRole like HelpMenuRole otherwise it will loose
         # this search field fonctionality
 
         self.help_menu = self.menuBar().addMenu("&Help")
         
 
         # Help Menu
 
         self.intro_active_frontend_action = QtGui.QAction("&Intro to IPython",
             self,
             triggered=self.intro_active_frontend
             )
         self.add_menu_action(self.help_menu, self.intro_active_frontend_action)
 
         self.quickref_active_frontend_action = QtGui.QAction("IPython &Cheat Sheet",
             self,
             triggered=self.quickref_active_frontend
             )
         self.add_menu_action(self.help_menu, self.quickref_active_frontend_action)
 
         self.guiref_active_frontend_action = QtGui.QAction("&Qt Console",
             self,
             triggered=self.guiref_active_frontend
             )
         self.add_menu_action(self.help_menu, self.guiref_active_frontend_action)
 
         self.onlineHelpAct = QtGui.QAction("Open Online &Help",
             self,
             triggered=self._open_online_help)
         self.add_menu_action(self.help_menu, self.onlineHelpAct)
 
     # minimize/maximize/fullscreen actions:
 
     def toggle_menu_bar(self):
         menu_bar = self.menuBar()
         if menu_bar.isVisible():
             menu_bar.setVisible(False)
         else:
             menu_bar.setVisible(True)
 
     def toggleMinimized(self):
         if not self.isMinimized():
             self.showMinimized()
         else:
             self.showNormal()
 
     def _open_online_help(self):
         filename="http://ipython.org/ipython-doc/stable/index.html"
         webbrowser.open(filename, new=1, autoraise=True)
 
     def toggleMaximized(self):
         if not self.isMaximized():
             self.showMaximized()
         else:
             self.showNormal()
 
     # Min/Max imizing while in full screen give a bug
     # when going out of full screen, at least on OSX
     def toggleFullScreen(self):
         if not self.isFullScreen():
             self.showFullScreen()
             if sys.platform == 'darwin':
                 self.maximizeAct.setEnabled(False)
                 self.minimizeAct.setEnabled(False)
         else:
             self.showNormal()
             if sys.platform == 'darwin':
                 self.maximizeAct.setEnabled(True)
                 self.minimizeAct.setEnabled(True)
 
     def close_active_frontend(self):
         self.close_tab(self.active_frontend)
 
     def restart_kernel_active_frontend(self):
         self.active_frontend.request_restart_kernel()
 
     def interrupt_kernel_active_frontend(self):
         self.active_frontend.request_interrupt_kernel()
 
     def cut_active_frontend(self):
         widget = self.active_frontend
         if widget.can_cut():
             widget.cut()
 
     def copy_active_frontend(self):
         widget = self.active_frontend
         if widget.can_copy():
             widget.copy()
 
     def copy_raw_active_frontend(self):
         self.active_frontend._copy_raw_action.trigger()
 
     def paste_active_frontend(self):
         widget = self.active_frontend
         if widget.can_paste():
             widget.paste()
 
     def undo_active_frontend(self):
         self.active_frontend.undo()
 
     def redo_active_frontend(self):
         self.active_frontend.redo()
 
     def reset_magic_active_frontend(self):
         self.active_frontend.execute("%reset")
 
     def history_magic_active_frontend(self):
         self.active_frontend.execute("%history")
 
     def save_magic_active_frontend(self):
         self.active_frontend.save_magic()
 
     def clear_magic_active_frontend(self):
         self.active_frontend.execute("%clear")
 
     def who_magic_active_frontend(self):
         self.active_frontend.execute("%who")
 
     def who_ls_magic_active_frontend(self):
         self.active_frontend.execute("%who_ls")
 
     def whos_magic_active_frontend(self):
         self.active_frontend.execute("%whos")
 
     def print_action_active_frontend(self):
         self.active_frontend.print_action.trigger()
 
     def export_action_active_frontend(self):
         self.active_frontend.export_action.trigger()
 
     def select_all_active_frontend(self):
         self.active_frontend.select_all_action.trigger()
 
     def increase_font_size_active_frontend(self):
         self.active_frontend.increase_font_size.trigger()
 
     def decrease_font_size_active_frontend(self):
         self.active_frontend.decrease_font_size.trigger()
 
     def reset_font_size_active_frontend(self):
         self.active_frontend.reset_font_size.trigger()
 
     def guiref_active_frontend(self):
         self.active_frontend.execute("%guiref")
 
     def intro_active_frontend(self):
         self.active_frontend.execute("?")
 
     def quickref_active_frontend(self):
         self.active_frontend.execute("%quickref")
     #---------------------------------------------------------------------------
     # QWidget interface
     #---------------------------------------------------------------------------
 
     def closeEvent(self, event):
         """ Forward the close event to every tabs contained by the windows
         """
         if self.tab_widget.count() == 0:
             # no tabs, just close
             event.accept()
             return
         # Do Not loop on the widget count as it change while closing
         title = self.window().windowTitle()
         cancel = QtGui.QMessageBox.Cancel
         okay = QtGui.QMessageBox.Ok
         
         if self.confirm_exit:
             msg = "Close all tabs, stop all kernels, and Quit?"
             closeall = QtGui.QPushButton("&Yes, quit everything", self)
             closeall.setShortcut('Y')
             box = QtGui.QMessageBox(QtGui.QMessageBox.Question,
                                     title, msg)
             # box.setInformativeText(info)
             box.addButton(cancel)
             box.addButton(closeall, QtGui.QMessageBox.YesRole)
             box.setDefaultButton(closeall)
             box.setEscapeButton(cancel)
             pixmap = QtGui.QPixmap(self._app.icon.pixmap(QtCore.QSize(64,64)))
             box.setIconPixmap(pixmap)
             reply = box.exec_()
         else:
             reply = okay
         
         if reply == cancel:
             return
         if reply == okay:
             while self.tab_widget.count() >= 1:
                 # prevent further confirmations:
                 widget = self.active_frontend
                 widget._confirm_exit = False
                 self.close_tab(widget)
         
         event.accept()