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 gi
  19  
  20  gi.require_version("Gdk", "3.0")
  21  gi.require_version("Gtk", "3.0")
  22  from gi.repository import GObject, Gtk  # noqa: E402
  23  
  24  warnings.warn(
  25      "The Gtk3 event loop for ipykernel is deprecated", category=DeprecationWarning, stacklevel=2
  26  )
  27  
  28  # -----------------------------------------------------------------------------
  29  # Classes and functions
  30  # -----------------------------------------------------------------------------
  31  
  32  
  33  class GTKEmbed:
  34      """A class to embed a kernel into the GTK main event loop."""
  35  
  36      def __init__(self, kernel):
  37          """Initialize the embed."""
  38          self.kernel = kernel
  39          # These two will later store the real gtk functions when we hijack them
  40          self.gtk_main = None
  41          self.gtk_main_quit = None
  42  
  43      def start(self):
  44          """Starts the GTK main event loop and sets our kernel startup routine."""
  45          # Register our function to initiate the kernel and start gtk
  46          GObject.idle_add(self._wire_kernel)
  47          Gtk.main()
  48  
  49      def _wire_kernel(self):
  50          """Initializes the kernel inside GTK.
  51  
  52          This is meant to run only once at startup, so it does its job and
  53          returns False to ensure it doesn't get run again by GTK.
  54          """
  55          self.gtk_main, self.gtk_main_quit = self._hijack_gtk()
  56          GObject.timeout_add(int(1000 * self.kernel._poll_interval), self.iterate_kernel)
  57          return False
  58  
  59      def iterate_kernel(self):
  60          """Run one iteration of the kernel and return True.
  61  
  62          GTK timer functions must return True to be called again, so we make the
  63          call to :meth:`do_one_iteration` and then return True for GTK.
  64          """
  65          self.kernel.do_one_iteration()
  66          return True
  67  
  68      def stop(self):
  69          """Stop the embed."""
  70          # FIXME: this one isn't getting called because we have no reliable
  71          # kernel shutdown.  We need to fix that: once the kernel has a
  72          # shutdown mechanism, it can call this.
  73          if self.gtk_main_quit:
  74              self.gtk_main_quit()
  75          sys.exit()
  76  
  77      def _hijack_gtk(self):
  78          """Hijack a few key functions in GTK for IPython integration.
  79  
  80          Modifies pyGTK's main and main_quit with a dummy so user code does not
  81          block IPython.  This allows us to use %run to run arbitrary pygtk
  82          scripts from a long-lived IPython session, and when they attempt to
  83          start or stop
  84  
  85          Returns
  86          -------
  87          The original functions that have been hijacked:
  88          - Gtk.main
  89          - Gtk.main_quit
  90          """
  91  
  92          def dummy(*args, **kw):
  93              """No-op."""
  94  
  95          # save and trap main and main_quit from gtk
  96          orig_main, Gtk.main = Gtk.main, dummy
  97          orig_main_quit, Gtk.main_quit = Gtk.main_quit, dummy
  98          return orig_main, orig_main_quit
  99