Fix a race in killing subprocesses.

IPython/frontend/wx/wx_frontend.py

@@ -1,523 +1,524 b''
 # encoding: utf-8 -*- test-case-name:
 # FIXME: Need to add tests.
 # ipython1.frontend.wx.tests.test_wx_frontend -*-
 
 """Classes to provide a Wx frontend to the
 IPython.kernel.core.interpreter.
 
 This class inherits from ConsoleWidget, that provides a console-like
 widget to provide a text-rendering widget suitable for a terminal.
 """
 
 __docformat__ = "restructuredtext en"
 
 #-------------------------------------------------------------------------------
 #       Copyright (C) 2008  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-------------------------------------------------------------------------------
 
 #-------------------------------------------------------------------------------
 # Imports
 #-------------------------------------------------------------------------------
 
 # Major library imports
 import re
 import __builtin__
 from time import sleep
 import sys
 from threading import Lock
 import string
 
 import wx
 from wx import stc
 
 # Ipython-specific imports.
 from IPython.frontend._process import PipedProcess
 from console_widget import ConsoleWidget
 from IPython.frontend.prefilterfrontend import PrefilterFrontEnd
 
 #-------------------------------------------------------------------------------
 # Constants 
 #-------------------------------------------------------------------------------
 
 _COMPLETE_BUFFER_BG = '#FAFAF1' # Nice green
 _INPUT_BUFFER_BG = '#FDFFD3' # Nice yellow
 _ERROR_BG = '#FFF1F1' # Nice red
 
 _COMPLETE_BUFFER_MARKER = 31
 _ERROR_MARKER = 30
 _INPUT_MARKER = 29
 
 prompt_in1 = \
         '\n\x01\x1b[0;34m\x02In [\x01\x1b[1;34m\x02$number\x01\x1b[0;34m\x02]: \x01\x1b[0m\x02'
 
 prompt_out = \
     '\x01\x1b[0;31m\x02Out[\x01\x1b[1;31m\x02$number\x01\x1b[0;31m\x02]: \x01\x1b[0m\x02'
 
 #-------------------------------------------------------------------------------
 # Classes to implement the Wx frontend
 #-------------------------------------------------------------------------------
 class WxController(ConsoleWidget, PrefilterFrontEnd):
     """Classes to provide a Wx frontend to the
     IPython.kernel.core.interpreter.
 
     This class inherits from ConsoleWidget, that provides a console-like
     widget to provide a text-rendering widget suitable for a terminal.
     """
 
     output_prompt_template = string.Template(prompt_out)
 
     input_prompt_template = string.Template(prompt_in1)
 
     # Print debug info on what is happening to the console.
     debug = False
 
     # The title of the terminal, as captured through the ANSI escape
     # sequences.
     def _set_title(self, title):
             return self.Parent.SetTitle(title)
 
     def _get_title(self):
             return self.Parent.GetTitle()
 
     title = property(_get_title, _set_title)
 
 
     # The buffer being edited.
     # We are duplicating the definition here because of multiple
     # inheritence
     def _set_input_buffer(self, string):
         ConsoleWidget._set_input_buffer(self, string)
         self._colorize_input_buffer()
 
     def _get_input_buffer(self):
         """ Returns the text in current edit buffer.
         """
         return ConsoleWidget._get_input_buffer(self)
 
     input_buffer = property(_get_input_buffer, _set_input_buffer)
 
 
     #--------------------------------------------------------------------------
     # Private Attributes
     #--------------------------------------------------------------------------
 
     # A flag governing the behavior of the input. Can be:
     #
     #       'readline' for readline-like behavior with a prompt 
     #            and an edit buffer.
     #       'raw_input' similar to readline, but triggered by a raw-input
     #           call. Can be used by subclasses to act differently.
     #       'subprocess' for sending the raw input directly to a
     #           subprocess.
     #       'buffering' for buffering of the input, that will be used
     #           when the input state switches back to another state.
     _input_state = 'readline'
 
     # Attribute to store reference to the pipes of a subprocess, if we
     # are running any.
     _running_process = False
 
     # A queue for writing fast streams to the screen without flooding the
     # event loop
     _out_buffer = []
 
     # A lock to lock the _out_buffer to make sure we don't empty it
     # while it is being swapped
     _out_buffer_lock = Lock()
 
     # The different line markers used to higlight the prompts.
     _markers = dict()
 
     #--------------------------------------------------------------------------
     # Public API
     #--------------------------------------------------------------------------
  
     def __init__(self, parent, id=wx.ID_ANY, pos=wx.DefaultPosition,
                  size=wx.DefaultSize,
                  style=wx.CLIP_CHILDREN|wx.WANTS_CHARS,
                  *args, **kwds):
         """ Create Shell instance.
         """
         ConsoleWidget.__init__(self, parent, id, pos, size, style)
         PrefilterFrontEnd.__init__(self, **kwds)
 
         # Marker for complete buffer.
         self.MarkerDefine(_COMPLETE_BUFFER_MARKER, stc.STC_MARK_BACKGROUND,
                                 background=_COMPLETE_BUFFER_BG)
         # Marker for current input buffer.
         self.MarkerDefine(_INPUT_MARKER, stc.STC_MARK_BACKGROUND,
                                 background=_INPUT_BUFFER_BG)
         # Marker for tracebacks.
         self.MarkerDefine(_ERROR_MARKER, stc.STC_MARK_BACKGROUND,
                                 background=_ERROR_BG)
 
         # A time for flushing the write buffer
         BUFFER_FLUSH_TIMER_ID = 100
         self._buffer_flush_timer = wx.Timer(self, BUFFER_FLUSH_TIMER_ID)
         wx.EVT_TIMER(self, BUFFER_FLUSH_TIMER_ID, self._buffer_flush)
 
         if 'debug' in kwds:
             self.debug = kwds['debug']
             kwds.pop('debug')
 
         # Inject self in namespace, for debug
         if self.debug:
             self.shell.user_ns['self'] = self
 
 
     def raw_input(self, prompt):
         """ A replacement from python's raw_input.
         """
         self.new_prompt(prompt)
         self._input_state = 'raw_input'
         if hasattr(self, '_cursor'):
             del self._cursor 
         self.SetCursor(wx.StockCursor(wx.CURSOR_CROSS))
         self.waiting = True
         self.__old_on_enter = self._on_enter
         def my_on_enter():
             self.waiting = False
         self._on_enter = my_on_enter
         # XXX: Busy waiting, ugly.
         while self.waiting:
             wx.Yield()
             sleep(0.1)
         self._on_enter = self.__old_on_enter
         self._input_state = 'buffering'
         self._cursor = wx.BusyCursor()
         return self.input_buffer.rstrip('\n')
 
 
     def system_call(self, command_string):
         self._input_state = 'subprocess'
         self._running_process = PipedProcess(command_string, 
                     out_callback=self.buffered_write,
                     end_callback = self._end_system_call)
         self._running_process.start()
         # XXX: another one of these polling loops to have a blocking
         # call
         wx.Yield()
         while self._running_process:
             wx.Yield()
             sleep(0.1)
         # Be sure to flush the buffer.
         self._buffer_flush(event=None)
 
 
     def do_calltip(self):
         """ Analyse current and displays useful calltip for it.
         """
         if self.debug:
             print >>sys.__stdout__, "do_calltip" 
         separators =  re.compile('[\s\{\}\[\]\(\)\= ,:]')
         symbol = self.input_buffer
         symbol_string = separators.split(symbol)[-1]
         base_symbol_string = symbol_string.split('.')[0]
         if base_symbol_string in self.shell.user_ns:
             symbol = self.shell.user_ns[base_symbol_string]
         elif base_symbol_string in self.shell.user_global_ns:
             symbol = self.shell.user_global_ns[base_symbol_string]
         elif base_symbol_string in __builtin__.__dict__:
             symbol = __builtin__.__dict__[base_symbol_string]
         else:
             return False
         try:
             for name in symbol_string.split('.')[1:] + ['__doc__']:
                 symbol = getattr(symbol, name)
             self.AutoCompCancel()
             wx.Yield()
             self.CallTipShow(self.GetCurrentPos(), symbol)
         except:
             # The retrieve symbol couldn't be converted to a string
             pass
 
 
     def _popup_completion(self, create=False):
         """ Updates the popup completion menu if it exists. If create is 
             true, open the menu.
         """
         if self.debug:
             print >>sys.__stdout__, "_popup_completion" 
         line = self.input_buffer
         if (self.AutoCompActive() and line and not line[-1] == '.') \
                     or create==True:
             suggestion, completions = self.complete(line)
             offset=0
             if completions:
                 complete_sep =  re.compile('[\s\{\}\[\]\(\)\= ,:]')
                 residual = complete_sep.split(line)[-1]
                 offset = len(residual)
                 self.pop_completion(completions, offset=offset)
                 if self.debug:
                     print >>sys.__stdout__, completions 
 
 
     def buffered_write(self, text):
         """ A write method for streams, that caches the stream in order
             to avoid flooding the event loop.
 
             This can be called outside of the main loop, in separate
             threads.
         """
         self._out_buffer_lock.acquire()
         self._out_buffer.append(text)
         self._out_buffer_lock.release()
         if not self._buffer_flush_timer.IsRunning():
             wx.CallAfter(self._buffer_flush_timer.Start, 
                                         milliseconds=100, oneShot=True)
 
 
     #--------------------------------------------------------------------------
     # LineFrontEnd interface 
     #--------------------------------------------------------------------------
  
     def execute(self, python_string, raw_string=None):
         self._input_state = 'buffering'
         self.CallTipCancel()
         self._cursor = wx.BusyCursor()
         if raw_string is None:
             raw_string = python_string
         end_line = self.current_prompt_line \
                         + max(1,  len(raw_string.split('\n'))-1)
         for i in range(self.current_prompt_line, end_line):
             if i in self._markers:
                 self.MarkerDeleteHandle(self._markers[i])
             self._markers[i] = self.MarkerAdd(i, _COMPLETE_BUFFER_MARKER)
         # Update the display:
         wx.Yield()
         self.GotoPos(self.GetLength())
         PrefilterFrontEnd.execute(self, python_string, raw_string=raw_string)
 
     def save_output_hooks(self):    
         self.__old_raw_input = __builtin__.raw_input
         PrefilterFrontEnd.save_output_hooks(self)
 
     def capture_output(self):
         __builtin__.raw_input = self.raw_input
         self.SetLexer(stc.STC_LEX_NULL)
         PrefilterFrontEnd.capture_output(self)
         
     
     def release_output(self):
         __builtin__.raw_input = self.__old_raw_input
         PrefilterFrontEnd.release_output(self)
         self.SetLexer(stc.STC_LEX_PYTHON)
 
 
     def after_execute(self):
         PrefilterFrontEnd.after_execute(self)
         # Clear the wait cursor
         if hasattr(self, '_cursor'):
             del self._cursor
         self.SetCursor(wx.StockCursor(wx.CURSOR_CHAR))
 
 
     def show_traceback(self):
         start_line = self.GetCurrentLine()
         PrefilterFrontEnd.show_traceback(self)
         wx.Yield()
         for i in range(start_line, self.GetCurrentLine()):
             self._markers[i] = self.MarkerAdd(i, _ERROR_MARKER)
 
     
     #--------------------------------------------------------------------------
     # FrontEndBase interface 
     #--------------------------------------------------------------------------
     
     def render_error(self, e):
         start_line = self.GetCurrentLine()
         self.write('\n' + e + '\n')
         for i in range(start_line, self.GetCurrentLine()):
             self._markers[i] = self.MarkerAdd(i, _ERROR_MARKER)
 
 
     #--------------------------------------------------------------------------
     # ConsoleWidget interface 
     #--------------------------------------------------------------------------
 
     def new_prompt(self, prompt):
         """ Display a new prompt, and start a new input buffer.
         """
         self._input_state = 'readline'
         ConsoleWidget.new_prompt(self, prompt)
         i = self.current_prompt_line
         self._markers[i] = self.MarkerAdd(i, _INPUT_MARKER)
 
 
     def write(self, *args, **kwargs):
         # Avoid multiple inheritence, be explicit about which
         # parent method class gets called
         ConsoleWidget.write(self, *args, **kwargs)
 
 
     def _on_key_down(self, event, skip=True):
         """ Capture the character events, let the parent
             widget handle them, and put our logic afterward.
         """
         # FIXME: This method needs to be broken down in smaller ones.
         current_line_number = self.GetCurrentLine()
         if event.KeyCode in (ord('c'), ord('C')) and event.ControlDown():
             # Capture Control-C
             if self._input_state == 'subprocess':
                 if self.debug:
                     print >>sys.__stderr__, 'Killing running process'
-                self._running_process.process.kill()
+                if hasattr(self._running_process, 'process'):
+                    self._running_process.process.kill()
             elif self._input_state == 'buffering':
                 if self.debug:
                     print >>sys.__stderr__, 'Raising KeyboardInterrupt'
                 raise KeyboardInterrupt
                 # XXX: We need to make really sure we
                 # get back to a prompt.
         elif self._input_state == 'subprocess' and (
                 ( event.KeyCode<256 and
                         not event.ControlDown() )
                     or 
                 ( event.KeyCode in (ord('d'), ord('D')) and
                   event.ControlDown())):
             #  We are running a process, we redirect keys.
             ConsoleWidget._on_key_down(self, event, skip=skip)
             char = chr(event.KeyCode)
             # Deal with some inconsistency in wx keycodes:
             if char == '\r':
                 char = '\n'
             elif not event.ShiftDown():
                 char = char.lower()
             if event.ControlDown() and event.KeyCode in (ord('d'), ord('D')):
                 char = '\04'
             self._running_process.process.stdin.write(char)
             self._running_process.process.stdin.flush()
         elif event.KeyCode in (ord('('), 57):
             # Calltips
             event.Skip()
             self.do_calltip()
         elif self.AutoCompActive() and not event.KeyCode == ord('\t'):
             event.Skip()
             if event.KeyCode in (wx.WXK_BACK, wx.WXK_DELETE): 
                 wx.CallAfter(self._popup_completion, create=True)
             elif not event.KeyCode in (wx.WXK_UP, wx.WXK_DOWN, wx.WXK_LEFT,
                             wx.WXK_RIGHT, wx.WXK_ESCAPE):
                 wx.CallAfter(self._popup_completion)
         else:
             # Up history
             if event.KeyCode == wx.WXK_UP and (
                     ( current_line_number == self.current_prompt_line and
                         event.Modifiers in (wx.MOD_NONE, wx.MOD_WIN) ) 
                     or event.ControlDown() ):
                 new_buffer = self.get_history_previous(
                                             self.input_buffer)
                 if new_buffer is not None:
                     self.input_buffer = new_buffer
                     if self.GetCurrentLine() > self.current_prompt_line:
                         # Go to first line, for seemless history up.
                         self.GotoPos(self.current_prompt_pos)
             # Down history
             elif event.KeyCode == wx.WXK_DOWN and (
                     ( current_line_number == self.LineCount -1 and
                         event.Modifiers in (wx.MOD_NONE, wx.MOD_WIN) ) 
                     or event.ControlDown() ):
                 new_buffer = self.get_history_next()
                 if new_buffer is not None:
                     self.input_buffer = new_buffer
             # Tab-completion
             elif event.KeyCode == ord('\t'):
                 last_line = self.input_buffer.split('\n')[-1]
                 if not re.match(r'^\s*$', last_line):
                     self.complete_current_input()
                     if self.AutoCompActive():
                         wx.CallAfter(self._popup_completion, create=True)
                 else:
                     event.Skip()
             else:
                 ConsoleWidget._on_key_down(self, event, skip=skip)
 
 
     def _on_key_up(self, event, skip=True):
         """ Called when any key is released.
         """
         if event.KeyCode in (59, ord('.')):
             # Intercepting '.'
             event.Skip()
             wx.CallAfter(self._popup_completion, create=True)
         else:
             ConsoleWidget._on_key_up(self, event, skip=skip)
 
 
     def _on_enter(self):
         """ Called on return key down, in readline input_state.
         """
         if self.debug:
             print >>sys.__stdout__, repr(self.input_buffer)
         PrefilterFrontEnd._on_enter(self)
 
 
     #--------------------------------------------------------------------------
     # EditWindow API
     #--------------------------------------------------------------------------
 
     def OnUpdateUI(self, event):
         """ Override the OnUpdateUI of the EditWindow class, to prevent 
             syntax highlighting both for faster redraw, and for more
             consistent look and feel.
         """
         if not self._input_state == 'readline':
             ConsoleWidget.OnUpdateUI(self, event)
 
     #--------------------------------------------------------------------------
     # Private API
     #--------------------------------------------------------------------------
  
     def _end_system_call(self):
         """ Called at the end of a system call.
         """
         self._input_state = 'buffering'
         self._running_process = False
 
 
     def _buffer_flush(self, event):
         """ Called by the timer to flush the write buffer.
             
             This is always called in the mainloop, by the wx timer.
         """
         self._out_buffer_lock.acquire()
         _out_buffer = self._out_buffer
         self._out_buffer = []
         self._out_buffer_lock.release()
         self.write(''.join(_out_buffer), refresh=False)
 
 
     def _colorize_input_buffer(self):
         """ Keep the input buffer lines at a bright color.
         """
         if not self._input_state in ('readline', 'raw_input'):
             return
         end_line = self.GetCurrentLine()
         if not sys.platform == 'win32':
             end_line += 1
         for i in range(self.current_prompt_line, end_line):
             if i in self._markers:
                 self.MarkerDeleteHandle(self._markers[i])
             self._markers[i] = self.MarkerAdd(i, _INPUT_MARKER)
 
 
 if __name__ == '__main__':
     class MainWindow(wx.Frame):
         def __init__(self, parent, id, title):
             wx.Frame.__init__(self, parent, id, title, size=(300,250))
             self._sizer = wx.BoxSizer(wx.VERTICAL)
             self.shell = WxController(self)
             self._sizer.Add(self.shell, 1, wx.EXPAND)
             self.SetSizer(self._sizer)
             self.SetAutoLayout(1)
             self.Show(True)
 
     app = wx.PySimpleApp()
     frame = MainWindow(None, wx.ID_ANY, 'Ipython')
     frame.shell.SetFocus()
     frame.SetSize((680, 460))
     self = frame.shell
 
     app.MainLoop()