# Standard library imports
import signal
import sys
# System library imports
from pygments.lexers import PythonLexer
from PyQt4 import QtCore, QtGui
# Local imports
from IPython.core.inputsplitter import InputSplitter
from IPython.frontend.qt.base_frontend_mixin import BaseFrontendMixin
from IPython.utils.traitlets import Bool, Type
from call_tip_widget import CallTipWidget
from completion_lexer import CompletionLexer
from console_widget import HistoryConsoleWidget
from pygments_highlighter import PygmentsHighlighter
class FrontendHighlighter(PygmentsHighlighter):
""" A PygmentsHighlighter that can be turned on and off and that ignores
prompts.
"""
def __init__(self, frontend):
super(FrontendHighlighter, self).__init__(frontend._control.document())
self._current_offset = 0
self._frontend = frontend
self.highlighting_on = False
def highlightBlock(self, qstring):
""" Highlight a block of text. Reimplemented to highlight selectively.
"""
if not self.highlighting_on:
return
# The input to this function is unicode string that may contain
# paragraph break characters, non-breaking spaces, etc. Here we acquire
# the string as plain text so we can compare it.
current_block = self.currentBlock()
string = self._frontend._get_block_plain_text(current_block)
# Decide whether to check for the regular or continuation prompt.
if current_block.contains(self._frontend._prompt_pos):
prompt = self._frontend._prompt
else:
prompt = self._frontend._continuation_prompt
# Don't highlight the part of the string that contains the prompt.
if string.startswith(prompt):
self._current_offset = len(prompt)
qstring.remove(0, len(prompt))
else:
self._current_offset = 0
PygmentsHighlighter.highlightBlock(self, qstring)
def rehighlightBlock(self, block):
""" Reimplemented to temporarily enable highlighting if disabled.
"""
old = self.highlighting_on
self.highlighting_on = True
super(FrontendHighlighter, self).rehighlightBlock(block)
self.highlighting_on = old
def setFormat(self, start, count, format):
""" Reimplemented to highlight selectively.
"""
start += self._current_offset
PygmentsHighlighter.setFormat(self, start, count, format)
class FrontendWidget(HistoryConsoleWidget, BaseFrontendMixin):
""" A Qt frontend for a generic Python kernel.
"""
# An option and corresponding signal for overriding the default kernel
# interrupt behavior.
custom_interrupt = Bool(False)
custom_interrupt_requested = QtCore.pyqtSignal()
# An option and corresponding signal for overriding the default kernel
# restart behavior.
custom_restart = Bool(False)
custom_restart_requested = QtCore.pyqtSignal()
# Emitted when an 'execute_reply' has been received from the kernel and
# processed by the FrontendWidget.
executed = QtCore.pyqtSignal(object)
# Protected class variables.
_highlighter_class = Type(FrontendHighlighter)
_input_splitter_class = Type(InputSplitter)
#---------------------------------------------------------------------------
# 'object' interface
#---------------------------------------------------------------------------
def __init__(self, *args, **kw):
super(FrontendWidget, self).__init__(*args, **kw)
# FrontendWidget protected variables.
self._call_tip_widget = CallTipWidget(self._control)
self._completion_lexer = CompletionLexer(PythonLexer())
self._hidden = False
self._highlighter = self._highlighter_class(self)
self._input_splitter = self._input_splitter_class(input_mode='block')
self._kernel_manager = None
# Configure the ConsoleWidget.
self.tab_width = 4
self._set_continuation_prompt('... ')
# Connect signal handlers.
document = self._control.document()
document.contentsChange.connect(self._document_contents_change)
#---------------------------------------------------------------------------
# 'ConsoleWidget' abstract interface
#---------------------------------------------------------------------------
def _is_complete(self, source, interactive):
""" Returns whether 'source' can be completely processed and a new
prompt created. When triggered by an Enter/Return key press,
'interactive' is True; otherwise, it is False.
"""
complete = self._input_splitter.push(source.expandtabs(4))
if interactive:
complete = not self._input_splitter.push_accepts_more()
return complete
def _execute(self, source, hidden):
""" Execute 'source'. If 'hidden', do not show any output.
"""
self.kernel_manager.xreq_channel.execute(source, hidden)
self._hidden = hidden
def _prompt_started_hook(self):
""" Called immediately after a new prompt is displayed.
"""
if not self._reading:
self._highlighter.highlighting_on = True
def _prompt_finished_hook(self):
""" Called immediately after a prompt is finished, i.e. when some input
will be processed and a new prompt displayed.
"""
if not self._reading:
self._highlighter.highlighting_on = False
def _tab_pressed(self):
""" Called when the tab key is pressed. Returns whether to continue
processing the event.
"""
# Perform tab completion if:
# 1) The cursor is in the input buffer.
# 2) There is a non-whitespace character before the cursor.
text = self._get_input_buffer_cursor_line()
if text is None:
return False
complete = bool(text[:self._get_input_buffer_cursor_column()].strip())
if complete:
self._complete()
return not complete
#---------------------------------------------------------------------------
# 'ConsoleWidget' protected interface
#---------------------------------------------------------------------------
def _event_filter_console_keypress(self, event):
""" Reimplemented to allow execution interruption.
"""
key = event.key()
if self._executing and self._control_key_down(event.modifiers()):
if key == QtCore.Qt.Key_C:
self._kernel_interrupt()
return True
elif key == QtCore.Qt.Key_Period:
self._kernel_restart()
return True
return super(FrontendWidget, self)._event_filter_console_keypress(event)
def _show_continuation_prompt(self):
""" Reimplemented for auto-indentation.
"""
super(FrontendWidget, self)._show_continuation_prompt()
spaces = self._input_splitter.indent_spaces
self._append_plain_text('\t' * (spaces / self.tab_width))
self._append_plain_text(' ' * (spaces % self.tab_width))
#---------------------------------------------------------------------------
# 'BaseFrontendMixin' abstract interface
#---------------------------------------------------------------------------
def _handle_complete_reply(self, rep):
""" Handle replies for tab completion.
"""
cursor = self._get_cursor()
if rep['parent_header']['msg_id'] == self._complete_id and \
cursor.position() == self._complete_pos:
text = '.'.join(self._get_context())
cursor.movePosition(QtGui.QTextCursor.Left, n=len(text))
self._complete_with_items(cursor, rep['content']['matches'])
def _handle_execute_reply(self, msg):
""" Handles replies for code execution.
"""
if not self._hidden:
# Make sure that all output from the SUB channel has been processed
# before writing a new prompt.
self.kernel_manager.sub_channel.flush()
content = msg['content']
status = content['status']
if status == 'ok':
self._process_execute_ok(msg)
elif status == 'error':
self._process_execute_error(msg)
elif status == 'abort':
self._process_execute_abort(msg)
self._show_interpreter_prompt_for_reply(msg)
self.executed.emit(msg)
def _handle_input_request(self, msg):
""" Handle requests for raw_input.
"""
if self._hidden:
raise RuntimeError('Request for raw input during hidden execution.')
# Make sure that all output from the SUB channel has been processed
# before entering readline mode.
self.kernel_manager.sub_channel.flush()
def callback(line):
self.kernel_manager.rep_channel.input(line)
self._readline(msg['content']['prompt'], callback=callback)
def _handle_object_info_reply(self, rep):
""" Handle replies for call tips.
"""
cursor = self._get_cursor()
if rep['parent_header']['msg_id'] == self._call_tip_id and \
cursor.position() == self._call_tip_pos:
doc = rep['content']['docstring']
if doc:
self._call_tip_widget.show_docstring(doc)
def _handle_pyout(self, msg):
""" Handle display hook output.
"""
if not self._hidden and self._is_from_this_session(msg):
self._append_plain_text(msg['content']['data'] + '\n')
def _handle_stream(self, msg):
""" Handle stdout, stderr, and stdin.
"""
if not self._hidden and self._is_from_this_session(msg):
self._append_plain_text(msg['content']['data'])
self._control.moveCursor(QtGui.QTextCursor.End)
def _started_channels(self):
""" Called when the KernelManager channels have started listening or
when the frontend is assigned an already listening KernelManager.
"""
self._control.clear()
self._append_plain_text(self._get_banner())
self._show_interpreter_prompt()
def _stopped_channels(self):
""" Called when the KernelManager channels have stopped listening or
when a listening KernelManager is removed from the frontend.
"""
self._executing = self._reading = False
self._highlighter.highlighting_on = False
#---------------------------------------------------------------------------
# 'FrontendWidget' interface
#---------------------------------------------------------------------------
def execute_file(self, path, hidden=False):
""" Attempts to execute file with 'path'. If 'hidden', no output is
shown.
"""
self.execute('execfile("%s")' % path, hidden=hidden)
#---------------------------------------------------------------------------
# 'FrontendWidget' protected interface
#---------------------------------------------------------------------------
def _call_tip(self):
""" Shows a call tip, if appropriate, at the current cursor location.
"""
# Decide if it makes sense to show a call tip
cursor = self._get_cursor()
cursor.movePosition(QtGui.QTextCursor.Left)
if cursor.document().characterAt(cursor.position()).toAscii() != '(':
return False
context = self._get_context(cursor)
if not context:
return False
# Send the metadata request to the kernel
name = '.'.join(context)
self._call_tip_id = self.kernel_manager.xreq_channel.object_info(name)
self._call_tip_pos = self._get_cursor().position()
return True
def _complete(self):
""" Performs completion at the current cursor location.
"""
context = self._get_context()
if context:
# Send the completion request to the kernel
self._complete_id = self.kernel_manager.xreq_channel.complete(
'.'.join(context), # text
self._get_input_buffer_cursor_line(), # line
self._get_input_buffer_cursor_column(), # cursor_pos
self.input_buffer) # block
self._complete_pos = self._get_cursor().position()
def _get_banner(self):
""" Gets a banner to display at the beginning of a session.
"""
banner = 'Python %s on %s\nType "help", "copyright", "credits" or ' \
'"license" for more information.'
return banner % (sys.version, sys.platform)
def _get_context(self, cursor=None):
""" Gets the context for the specified cursor (or the current cursor
if none is specified).
"""
if cursor is None:
cursor = self._get_cursor()
cursor.movePosition(QtGui.QTextCursor.StartOfBlock,
QtGui.QTextCursor.KeepAnchor)
text = str(cursor.selection().toPlainText())
return self._completion_lexer.get_context(text)
def _kernel_interrupt(self):
""" Attempts to interrupt the running kernel.
"""
if self.custom_interrupt:
self.custom_interrupt_requested.emit()
elif self.kernel_manager.has_kernel:
self.kernel_manager.signal_kernel(signal.SIGINT)
else:
self._append_plain_text('Kernel process is either remote or '
'unspecified. Cannot interrupt.\n')
def _kernel_restart(self):
""" Attempts to restart the running kernel.
"""
if self.custom_restart:
self.custom_restart_requested.emit()
elif self.kernel_manager.has_kernel:
try:
self.kernel_manager.restart_kernel()
except RuntimeError:
message = 'Kernel started externally. Cannot restart.\n'
self._append_plain_text(message)
else:
self._stopped_channels()
self._append_plain_text('Kernel restarting...\n')
self._show_interpreter_prompt()
else:
self._append_plain_text('Kernel process is either remote or '
'unspecified. Cannot restart.\n')
def _process_execute_abort(self, msg):
""" Process a reply for an aborted execution request.
"""
self._append_plain_text("ERROR: execution aborted\n")
def _process_execute_error(self, msg):
""" Process a reply for an execution request that resulted in an error.
"""
content = msg['content']
traceback = ''.join(content['traceback'])
self._append_plain_text(traceback)
def _process_execute_ok(self, msg):
""" Process a reply for a successful execution equest.
"""
payload = msg['content']['payload']
for item in payload:
if not self._process_execute_payload(item):
warning = 'Received unknown payload of type %s\n'
self._append_plain_text(warning % repr(item['source']))
def _process_execute_payload(self, item):
""" Process a single payload item from the list of payload items in an
execution reply. Returns whether the payload was handled.
"""
# The basic FrontendWidget doesn't handle payloads, as they are a
# mechanism for going beyond the standard Python interpreter model.
return False
def _show_interpreter_prompt(self):
""" Shows a prompt for the interpreter.
"""
self._show_prompt('>>> ')
def _show_interpreter_prompt_for_reply(self, msg):
""" Shows a prompt for the interpreter given an 'execute_reply' message.
"""
self._show_interpreter_prompt()
#------ Signal handlers ----------------------------------------------------
def _document_contents_change(self, position, removed, added):
""" Called whenever the document's content changes. Display a call tip
if appropriate.
"""
# Calculate where the cursor should be *after* the change:
position += added
document = self._control.document()
if position == self._get_cursor().position():
self._call_tip()