text: # -*- coding: utf-8 -*-
  #
  # Copyright © Spyder Project Contributors
  # Licensed under the terms of the MIT License
  # (see spyder/__init__.py for details)
  
  """
  Shell Widget for the IPython Console
  """
  
  # Standard library imports
  import os
  import os.path as osp
  import uuid
  from textwrap import dedent
  
  # Third party imports
  from qtpy.QtCore import Signal, QThread
  from qtpy.QtWidgets import QMessageBox
  from qtpy import QtCore, QtWidgets, QtGui
  
  # Local imports
  from spyder.config.base import (
      _, is_pynsist, running_in_mac_app, running_under_pytest)
  from spyder.py3compat import to_text_string
  from spyder.utils.palette import SpyderPalette
  from spyder.utils import encoding
  from spyder.utils.clipboard_helper import CLIPBOARD_HELPER
  from spyder.utils import syntaxhighlighters as sh
  from spyder.plugins.ipythonconsole.utils.style import (
      create_qss_style, create_style_class)
  from spyder.widgets.helperwidgets import MessageCheckBox
  from spyder.plugins.ipythonconsole.comms.kernelcomm import KernelComm
  from spyder.plugins.ipythonconsole.widgets import (
      ControlWidget, DebuggingWidget, FigureBrowserWidget, HelpWidget,
      NamepaceBrowserWidget, PageControlWidget)
  
  
  MODULES_FAQ_URL = (
      "https://docs.spyder-ide.org/5/faq.html#using-packages-installer")
  
  
  class ShellWidget(NamepaceBrowserWidget, HelpWidget, DebuggingWidget,
                    FigureBrowserWidget):
      """
      Shell widget for the IPython Console
  
      This is the widget in charge of executing code
      """
      # NOTE: Signals can't be assigned separately to each widget
      #       That's why we define all needed signals here.
  
      # For NamepaceBrowserWidget
      sig_show_syspath = Signal(object)
      sig_show_env = Signal(object)
  
      # For FigureBrowserWidget
      sig_new_inline_figure = Signal(object, str)
  
      # For DebuggingWidget
      sig_pdb_step = Signal(str, int)
      sig_pdb_state_changed = Signal(bool, dict)
      sig_pdb_prompt_ready = Signal()
  
      # For ShellWidget
      sig_focus_changed = Signal()
      new_client = Signal()
      sig_is_spykernel = Signal(object)
      sig_kernel_restarted_message = Signal(str)
      sig_kernel_restarted = Signal()
      sig_prompt_ready = Signal()
      sig_remote_execute = Signal()
  
      # For global working directory
      sig_working_directory_changed = Signal(str)
  
      # For printing internal errors
      sig_exception_occurred = Signal(dict)
  
      def __init__(self, ipyclient, additional_options, interpreter_versions,
                   is_external_kernel, is_spyder_kernel, *args, **kw):
          # To override the Qt widget used by RichJupyterWidget
          self.custom_control = ControlWidget
          self.custom_page_control = PageControlWidget
          self.custom_edit = True
          self.spyder_kernel_comm = KernelComm()
          self.spyder_kernel_comm.sig_exception_occurred.connect(
              self.sig_exception_occurred)
          super(ShellWidget, self).__init__(*args, **kw)
  
          self.ipyclient = ipyclient
          self.additional_options = additional_options
          self.interpreter_versions = interpreter_versions
          self.is_external_kernel = is_external_kernel
          self.is_spyder_kernel = is_spyder_kernel
          self._cwd = ''
  
          # Keyboard shortcuts
          self.shortcuts = self.create_shortcuts()
  
          # Set the color of the matched parentheses here since the qtconsole
          # uses a hard-coded value that is not modified when the color scheme is
          # set in the qtconsole constructor. See spyder-ide/spyder#4806.
          self.set_bracket_matcher_color_scheme(self.syntax_style)
  
          self.shutdown_called = False
          self.kernel_manager = None
          self.kernel_client = None
          self.shutdown_thread = None
          handlers = {
              'pdb_state': self.set_pdb_state,
              'pdb_execute': self.pdb_execute,
              'get_pdb_settings': self.get_pdb_settings,
              'run_cell': self.handle_run_cell,
              'cell_count': self.handle_cell_count,
              'current_filename': self.handle_current_filename,
              'get_file_code': self.handle_get_file_code,
              'set_debug_state': self.set_debug_state,
              'update_syspath': self.update_syspath,
              'do_where': self.do_where,
              'pdb_input': self.pdb_input,
              'request_interrupt_eventloop': self.request_interrupt_eventloop,
          }
          for request_id in handlers:
              self.spyder_kernel_comm.register_call_handler(
                  request_id, handlers[request_id])
  
          self._execute_queue = []
          self.executed.connect(self.pop_execute_queue)
  
          # Show a message in our installers to explain users how to use
          # modules that don't come with them.
          self.show_modules_message = is_pynsist() or running_in_mac_app()
  
      def __del__(self):
          """Avoid destroying shutdown_thread."""
          if (self.shutdown_thread is not None
                  and self.shutdown_thread.isRunning()):
              self.shutdown_thread.wait()
  
      # ---- Public API ---------------------------------------------------------
      def shutdown(self):
          """Shutdown kernel"""
          self.shutdown_called = True
          self.spyder_kernel_comm.close()
          self.kernel_manager.stop_restarter()
  
          self.shutdown_thread = QThread()
          self.shutdown_thread.run = self.kernel_manager.shutdown_kernel
          if self.kernel_client is not None:
              self.shutdown_thread.finished.connect(
                  self.kernel_client.stop_channels)
          self.shutdown_thread.start()
          super(ShellWidget, self).shutdown()
  
      def will_close(self, externally_managed):
          """
          Close communication channels with the kernel if shutdown was not
          called. If the kernel is not externally managed, shutdown the kernel
          as well.
          """
          if not self.shutdown_called and not externally_managed:
              # Make sure the channels are stopped
              self.spyder_kernel_comm.close()
              self.kernel_manager.stop_restarter()
              self.kernel_manager.shutdown_kernel(now=True)
              if self.kernel_client is not None:
                  self.kernel_client.stop_channels()
          if externally_managed:
              self.spyder_kernel_comm.close(shutdown_channel=False)
              if self.kernel_client is not None:
                  self.kernel_client.stop_channels()
          super(ShellWidget, self).will_close(externally_managed)
  
      def call_kernel(self, interrupt=False, blocking=False, callback=None,
                      timeout=None, display_error=False):
          """
          Send message to Spyder kernel connected to this console.
  
          Parameters
          ----------
          interrupt: bool
              Interrupt the kernel while running or in Pdb to perform
              the call.
          blocking: bool
              Make a blocking call, i.e. wait on this side until the
              kernel sends its response.
          callback: callable
              Callable to process the response sent from the kernel
              on the Spyder side.
          timeout: int or None
              Maximum time (in seconds) before giving up when making a
              blocking call to the kernel. If None, a default timeout
              (defined in commbase.py, present in spyder-kernels) is
              used.
          display_error: bool
              If an error occurs, should it be printed to the console.
          """
          return self.spyder_kernel_comm.remote_call(
              interrupt=interrupt,
              blocking=blocking,
              callback=callback,
              timeout=timeout,
              display_error=display_error
          )
  
      def set_kernel_client_and_manager(self, kernel_client, kernel_manager):
          """Set the kernel client and manager"""
          self.kernel_manager = kernel_manager
          self.kernel_client = kernel_client
          if self.is_spyder_kernel:
              self.spyder_kernel_comm.open_comm(kernel_client)
  
          # Redefine the complete method to work while debugging.
          self._redefine_complete_for_dbg(self.kernel_client)
  
      def pop_execute_queue(self):
          """Pop one waiting instruction."""
          if self._execute_queue:
              self.execute(*self._execute_queue.pop(0))
  
      # ---- Public API ---------------------------------------------------------
      def interrupt_kernel(self):
          """Attempts to interrupt the running kernel."""
          # Empty queue when interrupting
          # Fixes spyder-ide/spyder#7293.
          self._execute_queue = []
          super(ShellWidget, self).interrupt_kernel()
  
      def execute(self, source=None, hidden=False, interactive=False):
          """
          Executes source or the input buffer, possibly prompting for more
          input.
          """
          if self._executing:
              self._execute_queue.append((source, hidden, interactive))
              return
          super(ShellWidget, self).execute(source, hidden, interactive)
  
      def request_interrupt_eventloop(self):
          """Send a message to the kernel to interrupt the eventloop."""
          self.call_kernel()._interrupt_eventloop()
  
      def set_exit_callback(self):
          """Set exit callback for this shell."""
          self.exit_requested.connect(self.ipyclient.exit_callback)
  
      def is_running(self):
          if self.kernel_client is not None and \
            self.kernel_client.channels_running:
              return True
          else:
              return False
  
      def check_spyder_kernel(self):
          """Determine if the kernel is from Spyder."""
          code = u"getattr(get_ipython().kernel, 'set_value', False)"
          if self._reading:
              return
          else:
              self.silent_exec_method(code)
  
      def set_cwd(self, dirname):
          """Set shell current working directory."""
          if os.name == 'nt':
              # Use normpath instead of replacing '\' with '\\'
              # See spyder-ide/spyder#10785
              dirname = osp.normpath(dirname)
  
          if self.ipyclient.hostname is None:
              self.call_kernel(interrupt=self.is_debugging()).set_cwd(dirname)
              self._cwd = dirname
  
      def update_cwd(self):
          """Update current working directory in the kernel."""
          if self.kernel_client is None:
              return
          self.call_kernel(callback=self.remote_set_cwd).get_cwd()
  
      def remote_set_cwd(self, cwd):
          """Get current working directory from kernel."""
          self._cwd = cwd
          self.sig_working_directory_changed.emit(self._cwd)
  
      def set_bracket_matcher_color_scheme(self, color_scheme):
          """Set color scheme for matched parentheses."""
          bsh = sh.BaseSH(parent=self, color_scheme=color_scheme)
          mpcolor = bsh.get_matched_p_color()
          self._bracket_matcher.format.setBackground(mpcolor)
  
      def set_color_scheme(self, color_scheme, reset=True):
          """Set color scheme of the shell."""
          self.set_bracket_matcher_color_scheme(color_scheme)
          self.style_sheet, dark_color = create_qss_style(color_scheme)
          self.syntax_style = color_scheme
          self._style_sheet_changed()
          self._syntax_style_changed()
          if reset:
              self.reset(clear=True)
          if not dark_color:
              # Needed to change the colors of tracebacks
              self.silent_execute("%colors linux")
              self.call_kernel().set_sympy_forecolor(background_color='dark')
          else:
              self.silent_execute("%colors lightbg")
              self.call_kernel().set_sympy_forecolor(background_color='light')
  
      def update_syspath(self, path_dict, new_path_dict):
          """Update sys.path contents on kernel."""
          self.call_kernel(
              interrupt=True,
              blocking=False).update_syspath(path_dict, new_path_dict)
  
      def request_syspath(self):
          """Ask the kernel for sys.path contents."""
          self.call_kernel(
              interrupt=True, callback=self.sig_show_syspath.emit).get_syspath()
  
      def request_env(self):
          """Ask the kernel for environment variables."""
          self.call_kernel(
              interrupt=True, callback=self.sig_show_env.emit).get_env()
  
      def set_show_calltips(self, show_calltips):
          """Enable/Disable showing calltips."""
          self.enable_calltips = show_calltips
  
      def set_buffer_size(self, buffer_size):
          """Set buffer size for the shell."""
          self.buffer_size = buffer_size
  
      def set_completion_type(self, completion_type):
          """Set completion type (Graphical, Terminal, Plain) for the shell."""
          self.gui_completion = completion_type
  
      def set_in_prompt(self, in_prompt):
          """Set appereance of the In prompt."""
          self.in_prompt = in_prompt
  
      def set_out_prompt(self, out_prompt):
          """Set appereance of the Out prompt."""
          self.out_prompt = out_prompt
  
      def get_matplotlib_backend(self):
          """Call kernel to get current backend."""
          return self.call_kernel(
              interrupt=True,
              blocking=True).get_matplotlib_backend()
  
      def set_matplotlib_backend(self, backend_option, pylab=False):
          """Set matplotlib backend given a backend name."""
          cmd = "get_ipython().kernel.set_matplotlib_backend('{}', {})"
          self.execute(cmd.format(backend_option, pylab), hidden=True)
  
      def set_mpl_inline_figure_format(self, figure_format):
          """Set matplotlib inline figure format."""
          cmd = "get_ipython().kernel.set_mpl_inline_figure_format('{}')"
          self.execute(cmd.format(figure_format), hidden=True)
  
      def set_mpl_inline_resolution(self, resolution):
          """Set matplotlib inline resolution (savefig.dpi/figure.dpi)."""
          cmd = "get_ipython().kernel.set_mpl_inline_resolution({})"
          self.execute(cmd.format(resolution), hidden=True)
  
      def set_mpl_inline_figure_size(self, width, height):
          """Set matplotlib inline resolution (savefig.dpi/figure.dpi)."""
          cmd = "get_ipython().kernel.set_mpl_inline_figure_size({}, {})"
          self.execute(cmd.format(width, height), hidden=True)
  
      def set_mpl_inline_bbox_inches(self, bbox_inches):
          """Set matplotlib inline print figure bbox_inches ('tight' or not)."""
          cmd = "get_ipython().kernel.set_mpl_inline_bbox_inches({})"
          self.execute(cmd.format(bbox_inches), hidden=True)
  
      def set_jedi_completer(self, use_jedi):
          """Set if jedi completions should be used."""
          cmd = "get_ipython().kernel.set_jedi_completer({})"
          self.execute(cmd.format(use_jedi), hidden=True)
  
      def set_greedy_completer(self, use_greedy):
          """Set if greedy completions should be used."""
          cmd = "get_ipython().kernel.set_greedy_completer({})"
          self.execute(cmd.format(use_greedy), hidden=True)
  
      def set_autocall(self, autocall):
          """Set if autocall functionality is enabled or not."""
          cmd = "get_ipython().kernel.set_autocall({})"
          self.execute(cmd.format(autocall), hidden=True)
  
      # --- To handle the banner
      def long_banner(self):
          """Banner for clients with additional content."""
          # Default banner
          py_ver = self.interpreter_versions['python_version'].split('\n')[0]
          ipy_ver = self.interpreter_versions['ipython_version']
  
          banner_parts = [
              'Python %s\n' % py_ver,
              'Type "copyright", "credits" or "license" for more information.\n\n',
              'IPython %s -- An enhanced Interactive Python.\n' % ipy_ver
          ]
          banner = ''.join(banner_parts)
  
          # Pylab additions
          pylab_o = self.additional_options['pylab']
          autoload_pylab_o = self.additional_options['autoload_pylab']
          if pylab_o and autoload_pylab_o:
              pylab_message = ("\nPopulating the interactive namespace from "
                               "numpy and matplotlib\n")
              banner = banner + pylab_message
  
          # Sympy additions
          sympy_o = self.additional_options['sympy']
          if sympy_o:
              lines = """
  These commands were executed:
  >>> from __future__ import division
  >>> from sympy import *
  >>> x, y, z, t = symbols('x y z t')
  >>> k, m, n = symbols('k m n', integer=True)
  >>> f, g, h = symbols('f g h', cls=Function)
  """
              banner = banner + lines
          if (pylab_o and sympy_o):
              lines = """
  Warning: pylab (numpy and matplotlib) and symbolic math (sympy) are both
  enabled at the same time. Some pylab functions are going to be overrided by
  the sympy module (e.g. plot)
  """
              banner = banner + lines
  
          return banner
  
      def short_banner(self):
          """Short banner with Python and IPython versions only."""
          py_ver = self.interpreter_versions['python_version'].split(' ')[0]
          ipy_ver = self.interpreter_versions['ipython_version']
          banner = 'Python %s -- IPython %s' % (py_ver, ipy_ver)
          return banner
  
      # --- To define additional shortcuts
      def clear_console(self):
          self.execute("%clear")
          # Stop reading as any input has been removed.
          self._reading = False
  
      def _reset_namespace(self):
          warning = self.get_conf('show_reset_namespace_warning')
          self.reset_namespace(warning=warning)
  
      def reset_namespace(self, warning=False, message=False):
          """Reset the namespace by removing all names defined by the user."""
          # Don't show the warning when running our tests.
          if running_under_pytest():
              warning = False
  
          if warning:
              reset_str = _("Remove all variables")
              warn_str = _("All user-defined variables will be removed. "
                           "Are you sure you want to proceed?")
              box = MessageCheckBox(icon=QMessageBox.Warning, parent=self)
              box.setWindowTitle(reset_str)
              box.setStandardButtons(QMessageBox.Yes | QMessageBox.No)
              box.setDefaultButton(QMessageBox.Yes)
  
              box.set_checkbox_text(_("Don't show again."))
              box.set_checked(False)
              box.set_check_visible(True)
              box.setText(warn_str)
  
              box.buttonClicked.connect(
                  lambda button: self.handle_reset_message_answer(
                      box, button, message)
              )
              box.show()
          else:
              self._perform_reset(message)
  
      def handle_reset_message_answer(self, message_box, button, message):
          """
          Handle the answer of the reset namespace message box.
  
          Parameters
          ----------
          message_box
              Instance of the message box shown to the user.
          button: QPushButton
              Instance of the button clicked by the user on the dialog.
          message: bool
              Whether to show a message in the console telling users the
              namespace was reset.
          """
          if message_box.buttonRole(button) == QMessageBox.YesRole:
              self._update_reset_options(message_box)
              self._perform_reset(message)
          else:
              self._update_reset_options(message_box)
  
      def _perform_reset(self, message):
          """
          Perform the reset namespace operation.
  
          Parameters
          ----------
          message: bool
              Whether to show a message in the console telling users the
              namespace was reset.
          """
          # This is necessary to make resetting variables work in external
          # kernels.
          # See spyder-ide/spyder#9505.
          try:
              kernel_env = self.kernel_manager._kernel_spec.env
          except AttributeError:
              kernel_env = {}
  
          try:
              if self.is_waiting_pdb_input():
                  self.execute('%reset -f')
              else:
                  if message:
                      self.reset()
                      self._append_html(
                          _("<br><br>Removing all variables...<br>"),
                          before_prompt=False
                      )
                      self.insert_horizontal_ruler()
                  self.silent_execute("%reset -f")
                  if kernel_env.get('SPY_AUTOLOAD_PYLAB_O') == 'True':
                      self.silent_execute("from pylab import *")
                  if kernel_env.get('SPY_SYMPY_O') == 'True':
                      sympy_init = """
                          from __future__ import division
                          from sympy import *
                          x, y, z, t = symbols('x y z t')
                          k, m, n = symbols('k m n', integer=True)
                          f, g, h = symbols('f g h', cls=Function)
                          init_printing()"""
                      self.silent_execute(dedent(sympy_init))
                  if kernel_env.get('SPY_RUN_CYTHON') == 'True':
                      self.silent_execute("%reload_ext Cython")
  
                  # This doesn't need to interrupt the kernel because
                  # "%reset -f" is being executed before it.
                  # Fixes spyder-ide/spyder#12689
                  self.refresh_namespacebrowser(interrupt=False)
  
                  if self.is_spyder_kernel:
                      self.call_kernel().close_all_mpl_figures()
          except AttributeError:
              pass
  
      def _update_reset_options(self, message_box):
          """
          Update options and variables based on the interaction in the
          reset warning message box shown to the user.
          """
          self.set_conf(
              'show_reset_namespace_warning',
              not message_box.is_checked()
          )
          self.ipyclient.reset_warning = not message_box.is_checked()
  
      def create_shortcuts(self):
          """Create shortcuts for ipyconsole."""
          inspect = self.config_shortcut(
              self._control.inspect_current_object,
              context='Console',
              name='Inspect current object',
              parent=self)
  
          clear_console = self.config_shortcut(
              self.clear_console,
              context='Console',
              name='Clear shell',
              parent=self)
  
          restart_kernel = self.config_shortcut(
              self.ipyclient.restart_kernel,
              context='ipython_console',
              name='Restart kernel',
              parent=self)
  
          new_tab = self.config_shortcut(
              lambda: self.new_client.emit(),
              context='ipython_console',
              name='new tab',
              parent=self)
  
          reset_namespace = self.config_shortcut(
              lambda: self._reset_namespace(),
              context='ipython_console',
              name='reset namespace',
              parent=self)
  
          array_inline = self.config_shortcut(
              self._control.enter_array_inline,
              context='array_builder',
              name='enter array inline',
              parent=self)
  
          array_table = self.config_shortcut(
              self._control.enter_array_table,
              context='array_builder',
              name='enter array table',
              parent=self)
  
          clear_line = self.config_shortcut(
              self.ipyclient.clear_line,
              context='console',
              name='clear line',
              parent=self)
  
          return [inspect, clear_console, restart_kernel, new_tab,
                  reset_namespace, array_inline, array_table, clear_line]
  
      # --- To communicate with the kernel
      def silent_execute(self, code):
          """Execute code in the kernel without increasing the prompt"""
          try:
              if self.is_debugging():
                  self.pdb_execute(code, hidden=True)
              else:
                  self.kernel_client.execute(to_text_string(code), silent=True)
          except AttributeError:
              pass
  
      def silent_exec_method(self, code):
          """Silently execute a kernel method and save its reply
  
          The methods passed here **don't** involve getting the value
          of a variable but instead replies that can be handled by
          ast.literal_eval.
  
          To get a value see `get_value`
  
          Parameters
          ----------
          code : string
              Code that contains the kernel method as part of its
              string
  
          See Also
          --------
          handle_exec_method : Method that deals with the reply
  
          Note
          ----
          This is based on the _silent_exec_callback method of
          RichJupyterWidget. Therefore this is licensed BSD
          """
          # Generate uuid, which would be used as an indication of whether or
          # not the unique request originated from here
          local_uuid = to_text_string(uuid.uuid1())
          code = to_text_string(code)
          if self.kernel_client is None:
              return
  
          msg_id = self.kernel_client.execute('', silent=True,
                                              user_expressions={ local_uuid:code })
          self._kernel_methods[local_uuid] = code
          self._request_info['execute'][msg_id] = self._ExecutionRequest(msg_id,
                                                            'silent_exec_method')
  
      def handle_exec_method(self, msg):
          """
          Handle data returned by silent executions of kernel methods
  
          This is based on the _handle_exec_callback of RichJupyterWidget.
          Therefore this is licensed BSD.
          """
          user_exp = msg['content'].get('user_expressions')
          if not user_exp:
              return
          for expression in user_exp:
              if expression in self._kernel_methods:
                  # Process kernel reply
                  method = self._kernel_methods[expression]
                  reply = user_exp[expression]
                  data = reply.get('data')
                  if 'getattr' in method:
                      if data is not None and 'text/plain' in data:
                          is_spyder_kernel = data['text/plain']
                          if 'SpyderKernel' in is_spyder_kernel:
                              self.is_spyder_kernel = True
                              self.sig_is_spykernel.emit(self)
  
                  # Remove method after being processed
                  self._kernel_methods.pop(expression)
  
      def set_backend_for_mayavi(self, command):
          """
          Mayavi plots require the Qt backend, so we try to detect if one is
          generated to change backends
          """
          calling_mayavi = False
          lines = command.splitlines()
          for l in lines:
              if not l.startswith('#'):
                  if 'import mayavi' in l or 'from mayavi' in l:
                      calling_mayavi = True
                      break
          if calling_mayavi:
              message = _("Changing backend to Qt for Mayavi")
              self._append_plain_text(message + '\n')
              self.silent_execute("%gui inline\n%gui qt")
  
      def change_mpl_backend(self, command):
          """
          If the user is trying to change Matplotlib backends with
          %matplotlib, send the same command again to the kernel to
          correctly change it.
  
          Fixes spyder-ide/spyder#4002.
          """
          if (command.startswith('%matplotlib') and
                  len(command.splitlines()) == 1):
              if not 'inline' in command:
                  self.silent_execute(command)
  
      def append_html_message(self, html, before_prompt=False,
                              msg_type='warning'):
          """
          Append an html message enclosed in a box.
  
          Parameters
          ----------
          before_prompt: bool
              Whether to add the message before the next prompt.
          msg_type: str
              Type of message to be showm. Possible values are
              'warning' and 'error'.
          """
          # The message is displayed in a table with a single cell.
          table_properties = (
              "border='0.5'" +
              "width='90%'" +
              "cellpadding='8'" +
              "cellspacing='0'"
          )
  
          if msg_type == 'error':
              header = _("Error")
              bgcolor = SpyderPalette.COLOR_ERROR_2
          else:
              header = _("Warning")
              bgcolor = SpyderPalette.COLOR_WARN_1
  
          self._append_html(
              f"<div align='center'><table {table_properties}>" +
              f"<tr><th bgcolor='{bgcolor}'>{header}</th></tr>" +
              "<tr><td>" + html + "</td></tr>" +
              "</table></div>",
              before_prompt=before_prompt
          )
  
      def insert_horizontal_ruler(self):
          """
          Insert a horizontal ruler at the current cursor position.
  
          Notes
          -----
          This only works when adding a single horizontal line to a
          message. For more complex messages, please use
          append_html_message.
          """
          self._control.insert_horizontal_ruler()
  
      # ---- Spyder-kernels methods ---------------------------------------------
      def get_editor(self, filename):
          """Get editor for filename and set it as the current editor."""
          editorstack = self.get_editorstack()
          if editorstack is None:
              return None
  
          if not filename:
              return None
  
          index = editorstack.has_filename(filename)
          if index is None:
              return None
  
          return editorstack.data[index].editor
  
      def get_editorstack(self):
          """Get the current editorstack."""
          plugin = self.ipyclient.plugin
          if plugin.main.editor is not None:
              editor = plugin.main.editor
              return editor.get_current_editorstack()
          raise RuntimeError('No editorstack found.')
  
      def handle_get_file_code(self, filename, save_all=True):
          """
          Return the bytes that compose the file.
  
          Bytes are returned instead of str to support non utf-8 files.
          """
          editorstack = self.get_editorstack()
          if save_all and self.get_conf(
                  'save_all_before_run', default=True, section='editor'):
              editorstack.save_all(save_new_files=False)
          editor = self.get_editor(filename)
  
          if editor is None:
              # Load it from file instead
              text, _enc = encoding.read(filename)
              return text
  
          return editor.toPlainText()
  
      def handle_run_cell(self, cell_name, filename):
          """
          Get cell code from cell name and file name.
          """
          editorstack = self.get_editorstack()
          editor = self.get_editor(filename)
  
          if editor is None:
              raise RuntimeError(
                  "File {} not open in the editor".format(filename))
  
          editorstack.last_cell_call = (filename, cell_name)
  
          # The file is open, load code from editor
          return editor.get_cell_code(cell_name)
  
      def handle_cell_count(self, filename):
          """Get number of cells in file to loop."""
          editor = self.get_editor(filename)
  
          if editor is None:
              raise RuntimeError(
                  "File {} not open in the editor".format(filename))
  
          # The file is open, get cell count from editor
          return editor.get_cell_count()
  
      def handle_current_filename(self):
          """Get the current filename."""
          return self.get_editorstack().get_current_finfo().filename
  
      # ---- Public methods (overrode by us) ------------------------------------
      def request_restart_kernel(self):
          """Reimplemented to call our own restart mechanism."""
          self.ipyclient.restart_kernel()
  
      def adjust_indentation(self, line, indent_adjustment):
          """Adjust indentation."""
          if indent_adjustment == 0 or line == "":
              return line
  
          if indent_adjustment > 0:
              return ' ' * indent_adjustment + line
  
          max_indent = CLIPBOARD_HELPER.get_line_indentation(line)
          indent_adjustment = min(max_indent, -indent_adjustment)
  
          return line[indent_adjustment:]
  
      def paste(self, mode=QtGui.QClipboard.Clipboard):
          """ Paste the contents of the clipboard into the input region.
  
          Parameters
          ----------
          mode : QClipboard::Mode, optional [default QClipboard::Clipboard]
  
              Controls which part of the system clipboard is used. This can be
              used to access the selection clipboard in X11 and the Find buffer
              in Mac OS. By default, the regular clipboard is used.
          """
          if self._control.textInteractionFlags() & QtCore.Qt.TextEditable:
              # Make sure the paste is safe.
              self._keep_cursor_in_buffer()
              cursor = self._control.textCursor()
  
              # Remove any trailing newline, which confuses the GUI and forces
              # the user to backspace.
              text = QtWidgets.QApplication.clipboard().text(mode).rstrip()
  
              # Adjust indentation of multilines pastes
              if len(text.splitlines()) > 1:
                  lines_adjustment = CLIPBOARD_HELPER.remaining_lines_adjustment(
                      self._get_preceding_text())
                  eol_chars = "\n"
                  first_line, *remaining_lines = (text + eol_chars).splitlines()
                  remaining_lines = [
                      self.adjust_indentation(line, lines_adjustment)
                      for line in remaining_lines]
                  text = eol_chars.join([first_line, *remaining_lines])
  
              # dedent removes "common leading whitespace" but to preserve
              # relative indent of multiline code, we have to compensate for any
              # leading space on the first line, if we're pasting into
              # an indented position.
              cursor_offset = cursor.position() - self._get_line_start_pos()
              if text.startswith(' ' * cursor_offset):
                  text = text[cursor_offset:]
  
              self._insert_plain_text_into_buffer(cursor, dedent(text))
  
      def _get_preceding_text(self):
          """Get preciding text."""
          cursor = self._control.textCursor()
          text = cursor.selection().toPlainText()
          if text == "":
              return ""
          first_line_selection = text.splitlines()[0]
          cursor.setPosition(cursor.selectionStart())
          cursor.setPosition(cursor.block().position(),
                             QtGui.QTextCursor.KeepAnchor)
          preceding_text = cursor.selection().toPlainText()
          first_line = preceding_text + first_line_selection
          len_with_prompt = len(first_line)
          # Remove prompt
          first_line = self._highlighter.transform_classic_prompt(first_line)
          first_line = self._highlighter.transform_ipy_prompt(first_line)
  
          prompt_len = len_with_prompt - len(first_line)
          if prompt_len >= len(preceding_text):
              return ""
  
          return preceding_text[prompt_len:]
  
      def _save_clipboard_indentation(self):
          """
          Save the indentation corresponding to the clipboard data.
  
          Must be called right after copying.
          """
          CLIPBOARD_HELPER.save_indentation(self._get_preceding_text(), 4)
  
      def copy(self):
          """
          Copy the currently selected text to the clipboard.
          """
          super().copy()
          self._save_clipboard_indentation()
  
      def cut(self):
          """
          Copy the currently selected text to the clipboard and delete it
          if it's inside the input buffer.
          """
          super().cut()
          self._save_clipboard_indentation()
  
      # ---- Private methods (overrode by us) -----------------------------------
      def _handle_error(self, msg):
          """
          Reimplemented to reset the prompt if the error comes after the reply
          """
          self._process_execute_error(msg)
  
      def _context_menu_make(self, pos):
          """Reimplement the IPython context menu"""
          menu = super(ShellWidget, self)._context_menu_make(pos)
          return self.ipyclient.add_actions_to_context_menu(menu)
  
      def _banner_default(self):
          """
          Reimplement banner creation to let the user decide if he wants a
          banner or not
          """
          # Don't change banner for external kernels
          if self.is_external_kernel:
              return ''
          show_banner_o = self.additional_options['show_banner']
          if show_banner_o:
              return self.long_banner()
          else:
              return self.short_banner()
  
      def _kernel_restarted_message(self, died=True):
          msg = _("Kernel died, restarting") if died else _("Kernel restarting")
          self.sig_kernel_restarted_message.emit(msg)
  
      def _handle_kernel_restarted(self, *args, **kwargs):
          super(ShellWidget, self)._handle_kernel_restarted(*args, **kwargs)
          self.sig_kernel_restarted.emit()
  
      def _syntax_style_changed(self):
          """Refresh the highlighting with the current syntax style by class."""
          if self._highlighter is None:
              # ignore premature calls
              return
          if self.syntax_style:
              self._highlighter._style = create_style_class(self.syntax_style)
              self._highlighter._clear_caches()
          else:
              self._highlighter.set_style_sheet(self.style_sheet)
  
      def _prompt_started_hook(self):
          """Emit a signal when the prompt is ready."""
          if not self._reading:
              self._highlighter.highlighting_on = True
              self.sig_prompt_ready.emit()
  
      def _handle_execute_input(self, msg):
          """Handle an execute_input message"""
          super(ShellWidget, self)._handle_execute_input(msg)
          self.sig_remote_execute.emit()
  
      def _process_execute_error(self, msg):
          """
          Display a message when using our installers to explain users
          how to use modules that doesn't come with them.
          """
          super(ShellWidget, self)._process_execute_error(msg)
          if self.show_modules_message:
              error = msg['content']['traceback']
              if any(['ModuleNotFoundError' in frame or 'ImportError' in frame
                      for frame in error]):
                  self.append_html_message(
                      _("It seems you're trying to use a module that doesn't "
                        "come with our installer. Check "
                        "<a href='{}'>this FAQ</a> in our docs to learn how "
                        "to do this.").format(MODULES_FAQ_URL),
                      before_prompt=True
                  )
              self.show_modules_message = False
  
      #---- Qt methods ----------------------------------------------------------
      def focusInEvent(self, event):
          """Reimplement Qt method to send focus change notification"""
          self.sig_focus_changed.emit()
          return super(ShellWidget, self).focusInEvent(event)
  
      def focusOutEvent(self, event):
          """Reimplement Qt method to send focus change notification"""
          self.sig_focus_changed.emit()
          return super(ShellWidget, self).focusOutEvent(event)
  