1  """GUI support for the IPython ZeroMQ kernel - GTK toolkit support.
   2  """
   3  # -----------------------------------------------------------------------------
   4  #  Copyright (C) 2010-2011  The IPython Development Team
   5  #
   6  #  Distributed under the terms of the BSD License.  The full license is in
   7  #  the file LICENSE, distributed as part of this software.
   8  # -----------------------------------------------------------------------------
   9  
  10  # -----------------------------------------------------------------------------
  11  # Imports
  12  # -----------------------------------------------------------------------------
  13  # stdlib
  14  import sys
  15  import warnings
  16  
  17  # Third-party
  18  import gobject
  19  import gtk
  20  
  21  warnings.warn(
  22      "The Gtk3 event loop for ipykernel is deprecated", category=DeprecationWarning, stacklevel=2
  23  )
  24  
  25  # -----------------------------------------------------------------------------
  26  # Classes and functions
  27  # -----------------------------------------------------------------------------
  28  
  29  
  30  class GTKEmbed:
  31      """A class to embed a kernel into the GTK main event loop."""
  32  
  33      def __init__(self, kernel):
  34          """Initialize the embed."""
  35          self.kernel = kernel
  36          # These two will later store the real gtk functions when we hijack them
  37          self.gtk_main = None
  38          self.gtk_main_quit = None
  39  
  40      def start(self):
  41          """Starts the GTK main event loop and sets our kernel startup routine."""
  42          # Register our function to initiate the kernel and start gtk
  43          gobject.idle_add(self._wire_kernel)
  44          gtk.main()
  45  
  46      def _wire_kernel(self):
  47          """Initializes the kernel inside GTK.
  48  
  49          This is meant to run only once at startup, so it does its job and
  50          returns False to ensure it doesn't get run again by GTK.
  51          """
  52          self.gtk_main, self.gtk_main_quit = self._hijack_gtk()
  53          gobject.timeout_add(int(1000 * self.kernel._poll_interval), self.iterate_kernel)
  54          return False
  55  
  56      def iterate_kernel(self):
  57          """Run one iteration of the kernel and return True.
  58  
  59          GTK timer functions must return True to be called again, so we make the
  60          call to :meth:`do_one_iteration` and then return True for GTK.
  61          """
  62          self.kernel.do_one_iteration()
  63          return True
  64  
  65      def stop(self):
  66          """Stop the embed."""
  67          # FIXME: this one isn't getting called because we have no reliable
  68          # kernel shutdown.  We need to fix that: once the kernel has a
  69          # shutdown mechanism, it can call this.
  70          if self.gtk_main_quit:
  71              self.gtk_main_quit()
  72          sys.exit()
  73  
  74      def _hijack_gtk(self):
  75          """Hijack a few key functions in GTK for IPython integration.
  76  
  77          Modifies pyGTK's main and main_quit with a dummy so user code does not
  78          block IPython.  This allows us to use %run to run arbitrary pygtk
  79          scripts from a long-lived IPython session, and when they attempt to
  80          start or stop
  81  
  82          Returns
  83          -------
  84          The original functions that have been hijacked:
  85          - gtk.main
  86          - gtk.main_quit
  87          """
  88  
  89          def dummy(*args, **kw):
  90              """No-op."""
  91  
  92          # save and trap main and main_quit from gtk
  93          orig_main, gtk.main = gtk.main, dummy
  94          orig_main_quit, gtk.main_quit = gtk.main_quit, dummy
  95          return orig_main, orig_main_quit
  96