"""Frontend widget for the Qt Console""" # Copyright (c) Jupyter Development Team # Distributed under the terms of the Modified BSD License. from __future__ import print_function from collections import namedtuple import sys import uuid import re from qtpy import QtCore, QtGui, QtWidgets from ipython_genutils import py3compat from ipython_genutils.importstring import import_item from qtconsole.base_frontend_mixin import BaseFrontendMixin from traitlets import Any, Bool, Instance, Unicode, DottedObjectName, default from .bracket_matcher import BracketMatcher from .call_tip_widget import CallTipWidget from .history_console_widget import HistoryConsoleWidget from .pygments_highlighter import PygmentsHighlighter class FrontendHighlighter(PygmentsHighlighter): """ A PygmentsHighlighter that understands and ignores prompts. """ def __init__(self, frontend, lexer=None): super(FrontendHighlighter, self).__init__(frontend._control.document(), lexer=lexer) self._current_offset = 0 self._frontend = frontend self.highlighting_on = False self._classic_prompt_re = re.compile( r'^(%s)?([ \t]*>>> |^[ \t]*\.\.\. )' % re.escape(frontend.other_output_prefix) ) self._ipy_prompt_re = re.compile( r'^(%s)?([ \t]*In \[\d+\]: |[ \t]*\ \ \ \.\.\.+: )' % re.escape(frontend.other_output_prefix) ) def transform_classic_prompt(self, line): """Handle inputs that start with '>>> ' syntax.""" if not line or line.isspace(): return line m = self._classic_prompt_re.match(line) if m: return line[len(m.group(0)):] else: return line def transform_ipy_prompt(self, line): """Handle inputs that start classic IPython prompt syntax.""" if not line or line.isspace(): return line m = self._ipy_prompt_re.match(line) if m: return line[len(m.group(0)):] else: return line def highlightBlock(self, string): """ Highlight a block of text. Reimplemented to highlight selectively. """ if not hasattr(self, 'highlighting_on') or not self.highlighting_on: return # The input to this function is a 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) # Only highlight if we can identify a prompt, but make sure not to # highlight the prompt. without_prompt = self.transform_ipy_prompt(string) diff = len(string) - len(without_prompt) if diff > 0: self._current_offset = diff super(FrontendHighlighter, self).highlightBlock(without_prompt) 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 super(FrontendHighlighter, self).setFormat(start, count, format) class FrontendWidget(HistoryConsoleWidget, BaseFrontendMixin): """ A Qt frontend for a generic Python kernel. """ # The text to show when the kernel is (re)started. banner = Unicode(config=True) kernel_banner = Unicode() # Whether to show the banner _display_banner = Bool(False) # An option and corresponding signal for overriding the default kernel # interrupt behavior. custom_interrupt = Bool(False) custom_interrupt_requested = QtCore.Signal() # An option and corresponding signals for overriding the default kernel # restart behavior. custom_restart = Bool(False) custom_restart_kernel_died = QtCore.Signal(float) custom_restart_requested = QtCore.Signal() # Whether to automatically show calltips on open-parentheses. enable_calltips = Bool(True, config=True, help="Whether to draw information calltips on open-parentheses.") clear_on_kernel_restart = Bool(True, config=True, help="Whether to clear the console when the kernel is restarted") confirm_restart = Bool(True, config=True, help="Whether to ask for user confirmation when restarting kernel") lexer_class = DottedObjectName(config=True, help="The pygments lexer class to use." ) def _lexer_class_changed(self, name, old, new): lexer_class = import_item(new) self.lexer = lexer_class() def _lexer_class_default(self): if py3compat.PY3: return 'pygments.lexers.Python3Lexer' else: return 'pygments.lexers.PythonLexer' lexer = Any() def _lexer_default(self): lexer_class = import_item(self.lexer_class) return lexer_class() # Emitted when a user visible 'execute_request' has been submitted to the # kernel from the FrontendWidget. Contains the code to be executed. executing = QtCore.Signal(object) # Emitted when a user-visible 'execute_reply' has been received from the # kernel and processed by the FrontendWidget. Contains the response message. executed = QtCore.Signal(object) # Emitted when an exit request has been received from the kernel. exit_requested = QtCore.Signal(object) _CallTipRequest = namedtuple('_CallTipRequest', ['id', 'pos']) _CompletionRequest = namedtuple('_CompletionRequest', ['id', 'code', 'pos']) _ExecutionRequest = namedtuple('_ExecutionRequest', ['id', 'kind']) _local_kernel = False _highlighter = Instance(FrontendHighlighter, allow_none=True) # ------------------------------------------------------------------------- # 'Object' interface # ------------------------------------------------------------------------- def __init__(self, local_kernel=_local_kernel, *args, **kw): super(FrontendWidget, self).__init__(*args, **kw) # FrontendWidget protected variables. self._bracket_matcher = BracketMatcher(self._control) self._call_tip_widget = CallTipWidget(self._control) self._copy_raw_action = QtWidgets.QAction('Copy (Raw Text)', None) self._hidden = False self._highlighter = FrontendHighlighter(self, lexer=self.lexer) self._kernel_manager = None self._kernel_client = None self._request_info = {} self._request_info['execute'] = {} self._callback_dict = {} self._display_banner = True # Configure the ConsoleWidget. self.tab_width = 4 self._set_continuation_prompt('... ') # Configure the CallTipWidget. self._call_tip_widget.setFont(self.font) self.font_changed.connect(self._call_tip_widget.setFont) # Configure actions. action = self._copy_raw_action key = QtCore.Qt.CTRL | QtCore.Qt.SHIFT | QtCore.Qt.Key_C action.setEnabled(False) action.setShortcut(QtGui.QKeySequence(key)) action.setShortcutContext(QtCore.Qt.WidgetWithChildrenShortcut) action.triggered.connect(self.copy_raw) self.copy_available.connect(action.setEnabled) self.addAction(action) # Connect signal handlers. document = self._control.document() document.contentsChange.connect(self._document_contents_change) # Set flag for whether we are connected via localhost. self._local_kernel = local_kernel # Whether or not a clear_output call is pending new output. self._pending_clearoutput = False #--------------------------------------------------------------------------- # 'ConsoleWidget' public interface #--------------------------------------------------------------------------- def copy(self): """ Copy the currently selected text to the clipboard, removing prompts. """ if self._page_control is not None and self._page_control.hasFocus(): self._page_control.copy() elif self._control.hasFocus(): text = self._control.textCursor().selection().toPlainText() if text: # Remove prompts. lines = text.splitlines() lines = map(self._highlighter.transform_classic_prompt, lines) lines = map(self._highlighter.transform_ipy_prompt, lines) text = '\n'.join(lines) # Needed to prevent errors when copying the prompt. # See issue 264 try: was_newline = text[-1] == '\n' except IndexError: was_newline = False if was_newline: # user doesn't need newline text = text[:-1] QtWidgets.QApplication.clipboard().setText(text) else: self.log.debug("frontend widget : unknown copy target") #--------------------------------------------------------------------------- # 'ConsoleWidget' abstract interface #--------------------------------------------------------------------------- def _execute(self, source, hidden): """ Execute 'source'. If 'hidden', do not show any output. See parent class :meth:`execute` docstring for full details. """ msg_id = self.kernel_client.execute(source, hidden) self._request_info['execute'][msg_id] = self._ExecutionRequest(msg_id, 'user') self._hidden = hidden if not hidden: self.executing.emit(source) 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. # 3) There is no active selection. text = self._get_input_buffer_cursor_line() if text is None: return False non_ws_before = bool(text[:self._get_input_buffer_cursor_column()].strip()) complete = non_ws_before and self._get_cursor().selectedText() == '' if complete: self._complete() return not complete #--------------------------------------------------------------------------- # 'ConsoleWidget' protected interface #--------------------------------------------------------------------------- def _context_menu_make(self, pos): """ Reimplemented to add an action for raw copy. """ menu = super(FrontendWidget, self)._context_menu_make(pos) for before_action in menu.actions(): if before_action.shortcut().matches(QtGui.QKeySequence.Paste) == \ QtGui.QKeySequence.ExactMatch: menu.insertAction(before_action, self._copy_raw_action) break return menu def request_interrupt_kernel(self): if self._executing: self.interrupt_kernel() def request_restart_kernel(self): message = 'Are you sure you want to restart the kernel?' self.restart_kernel(message, now=False) def _event_filter_console_keypress(self, event): """ Reimplemented for execution interruption and smart backspace. """ key = event.key() if self._control_key_down(event.modifiers(), include_command=False): if key == QtCore.Qt.Key_C and self._executing: self.request_interrupt_kernel() return True elif key == QtCore.Qt.Key_Period: self.request_restart_kernel() return True elif not event.modifiers() & QtCore.Qt.AltModifier: # Smart backspace: remove four characters in one backspace if: # 1) everything left of the cursor is whitespace # 2) the four characters immediately left of the cursor are spaces if key == QtCore.Qt.Key_Backspace: col = self._get_input_buffer_cursor_column() cursor = self._control.textCursor() if col > 3 and not cursor.hasSelection(): text = self._get_input_buffer_cursor_line()[:col] if text.endswith(' ') and not text.strip(): cursor.movePosition(QtGui.QTextCursor.Left, QtGui.QTextCursor.KeepAnchor, 4) cursor.removeSelectedText() return True return super(FrontendWidget, self)._event_filter_console_keypress(event) #--------------------------------------------------------------------------- # 'BaseFrontendMixin' abstract interface #--------------------------------------------------------------------------- def _handle_clear_output(self, msg): """Handle clear output messages.""" if self.include_output(msg): wait = msg['content'].get('wait', True) if wait: self._pending_clearoutput = True else: self.clear_output() def _silent_exec_callback(self, expr, callback): """Silently execute `expr` in the kernel and call `callback` with reply the `expr` is evaluated silently in the kernel (without) output in the frontend. Call `callback` with the `repr `_ as first argument Parameters ---------- expr : string valid string to be executed by the kernel. callback : function function accepting one argument, as a string. The string will be the `repr` of the result of evaluating `expr` The `callback` is called with the `repr()` of the result of `expr` as first argument. To get the object, do `eval()` on the passed value. See Also -------- _handle_exec_callback : private method, deal with calling callback with reply """ # generate uuid, which would be used as an indication of whether or # not the unique request originated from here (can use msg id ?) local_uuid = str(uuid.uuid1()) msg_id = self.kernel_client.execute('', silent=True, user_expressions={ local_uuid:expr }) self._callback_dict[local_uuid] = callback self._request_info['execute'][msg_id] = self._ExecutionRequest(msg_id, 'silent_exec_callback') def _handle_exec_callback(self, msg): """Execute `callback` corresponding to `msg` reply, after ``_silent_exec_callback`` Parameters ---------- msg : raw message send by the kernel containing an `user_expressions` and having a 'silent_exec_callback' kind. Notes ----- This function will look for a `callback` associated with the corresponding message id. Association has been made by `_silent_exec_callback`. `callback` is then called with the `repr()` of the value of corresponding `user_expressions` as argument. `callback` is then removed from the known list so that any message coming again with the same id won't trigger it. """ user_exp = msg['content'].get('user_expressions') if not user_exp: return for expression in user_exp: if expression in self._callback_dict: self._callback_dict.pop(expression)(user_exp[expression]) def _handle_execute_reply(self, msg): """ Handles replies for code execution. """ self.log.debug("execute_reply: %s", msg.get('content', '')) msg_id = msg['parent_header']['msg_id'] info = self._request_info['execute'].get(msg_id) # unset reading flag, because if execute finished, raw_input can't # still be pending. self._reading = False # Note: If info is NoneType, this is ignored if info and info.kind == 'user' and not self._hidden: # Make sure that all output from the SUB channel has been processed # before writing a new prompt. self.kernel_client.iopub_channel.flush() # Reset the ANSI style information to prevent bad text in stdout # from messing up our colors. We're not a true terminal so we're # allowed to do this. if self.ansi_codes: self._ansi_processor.reset_sgr() content = msg['content'] status = content['status'] if status == 'ok': self._process_execute_ok(msg) elif status == 'aborted': self._process_execute_abort(msg) self._show_interpreter_prompt_for_reply(msg) self.executed.emit(msg) self._request_info['execute'].pop(msg_id) elif info and info.kind == 'silent_exec_callback' and not self._hidden: self._handle_exec_callback(msg) self._request_info['execute'].pop(msg_id) elif info and not self._hidden: raise RuntimeError("Unknown handler for %s" % info.kind) def _handle_error(self, msg): """ Handle error messages. """ self._process_execute_error(msg) def _handle_input_request(self, msg): """ Handle requests for raw_input. """ self.log.debug("input: %s", msg.get('content', '')) 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_client.iopub_channel.flush() def callback(line): self._finalize_input_request() self.kernel_client.input(line) if self._reading: self.log.debug("Got second input request, assuming first was interrupted.") self._reading = False self._readline(msg['content']['prompt'], callback=callback, password=msg['content']['password']) def _kernel_restarted_message(self, died=True): msg = "Kernel died, restarting" if died else "Kernel restarting" self._append_html("
%s

" % msg, before_prompt=False ) def _handle_kernel_died(self, since_last_heartbeat): """Handle the kernel's death (if we do not own the kernel). """ self.log.warning("kernel died: %s", since_last_heartbeat) if self.custom_restart: self.custom_restart_kernel_died.emit(since_last_heartbeat) else: self._kernel_restarted_message(died=True) self.reset() def _handle_kernel_restarted(self, died=True): """Notice that the autorestarter restarted the kernel. There's nothing to do but show a message. """ self.log.warning("kernel restarted") self._kernel_restarted_message(died=died) self.reset() def _handle_inspect_reply(self, rep): """Handle replies for call tips.""" self.log.debug("oinfo: %s", rep.get('content', '')) cursor = self._get_cursor() info = self._request_info.get('call_tip') if info and info.id == rep['parent_header']['msg_id'] and \ info.pos == cursor.position(): content = rep['content'] if content.get('status') == 'ok' and content.get('found', False): self._call_tip_widget.show_inspect_data(content) def _handle_execute_result(self, msg): """ Handle display hook output. """ self.log.debug("execute_result: %s", msg.get('content', '')) if self.include_output(msg): self.flush_clearoutput() text = msg['content']['data'] self._append_plain_text(text + '\n', before_prompt=True) def _handle_stream(self, msg): """ Handle stdout, stderr, and stdin. """ self.log.debug("stream: %s", msg.get('content', '')) if self.include_output(msg): self.flush_clearoutput() self.append_stream(msg['content']['text']) def _handle_shutdown_reply(self, msg): """ Handle shutdown signal, only if from other console. """ self.log.debug("shutdown: %s", msg.get('content', '')) restart = msg.get('content', {}).get('restart', False) if not self._hidden and not self.from_here(msg): # got shutdown reply, request came from session other than ours if restart: # someone restarted the kernel, handle it self._handle_kernel_restarted(died=False) else: # kernel was shutdown permanently # this triggers exit_requested if the kernel was local, # and a dialog if the kernel was remote, # so we don't suddenly clear the qtconsole without asking. if self._local_kernel: self.exit_requested.emit(self) else: title = self.window().windowTitle() reply = QtWidgets.QMessageBox.question(self, title, "Kernel has been shutdown permanently. " "Close the Console?", QtWidgets.QMessageBox.Yes,QtWidgets.QMessageBox.No) if reply == QtWidgets.QMessageBox.Yes: self.exit_requested.emit(self) def _handle_status(self, msg): """Handle status message""" # This is where a busy/idle indicator would be triggered, # when we make one. state = msg['content'].get('execution_state', '') if state == 'starting': # kernel started while we were running if self._executing: self._handle_kernel_restarted(died=True) elif state == 'idle': pass elif state == 'busy': pass def _started_channels(self): """ Called when the KernelManager channels have started listening or when the frontend is assigned an already listening KernelManager. """ self.reset(clear=True) #--------------------------------------------------------------------------- # 'FrontendWidget' public interface #--------------------------------------------------------------------------- def copy_raw(self): """ Copy the currently selected text to the clipboard without attempting to remove prompts or otherwise alter the text. """ self._control.copy() def interrupt_kernel(self): """ Attempts to interrupt the running kernel. Also unsets _reading flag, to avoid runtime errors if raw_input is called again. """ if self.custom_interrupt: self._reading = False self.custom_interrupt_requested.emit() elif self.kernel_manager: self._reading = False self.kernel_manager.interrupt_kernel() else: self._append_plain_text('Cannot interrupt a kernel I did not start.\n') def reset(self, clear=False): """ Resets the widget to its initial state if ``clear`` parameter is True, otherwise prints a visual indication of the fact that the kernel restarted, but does not clear the traces from previous usage of the kernel before it was restarted. With ``clear=True``, it is similar to ``%clear``, but also re-writes the banner and aborts execution if necessary. """ if self._executing: self._executing = False self._request_info['execute'] = {} self._reading = False self._highlighter.highlighting_on = False if clear: self._control.clear() if self._display_banner: self._append_plain_text(self.banner) if self.kernel_banner: self._append_plain_text(self.kernel_banner) # update output marker for stdout/stderr, so that startup # messages appear after banner: self._show_interpreter_prompt() def restart_kernel(self, message, now=False): """ Attempts to restart the running kernel. """ # FIXME: now should be configurable via a checkbox in the dialog. Right # now at least the heartbeat path sets it to True and the manual restart # to False. But those should just be the pre-selected states of a # checkbox that the user could override if so desired. But I don't know # enough Qt to go implementing the checkbox now. if self.custom_restart: self.custom_restart_requested.emit() return if self.kernel_manager: # Pause the heart beat channel to prevent further warnings. self.kernel_client.hb_channel.pause() # Prompt the user to restart the kernel. Un-pause the heartbeat if # they decline. (If they accept, the heartbeat will be un-paused # automatically when the kernel is restarted.) if self.confirm_restart: buttons = QtWidgets.QMessageBox.Yes | QtWidgets.QMessageBox.No result = QtWidgets.QMessageBox.question(self, 'Restart kernel?', message, buttons) do_restart = result == QtWidgets.QMessageBox.Yes else: # confirm_restart is False, so we don't need to ask user # anything, just do the restart do_restart = True if do_restart: try: self.kernel_manager.restart_kernel(now=now) except RuntimeError as e: self._append_plain_text( 'Error restarting kernel: %s\n' % e, before_prompt=True ) else: self._append_html("
Restarting kernel...\n

", before_prompt=True, ) else: self.kernel_client.hb_channel.unpause() else: self._append_plain_text( 'Cannot restart a Kernel I did not start\n', before_prompt=True ) def append_stream(self, text): """Appends text to the output stream.""" self._append_plain_text(text, before_prompt=True) def flush_clearoutput(self): """If a clearoutput is pending, execute it.""" if self._pending_clearoutput: self._pending_clearoutput = False self.clear_output() def clear_output(self): """Clears the current line of output.""" cursor = self._control.textCursor() cursor.beginEditBlock() cursor.movePosition(cursor.StartOfLine, cursor.KeepAnchor) cursor.insertText('') cursor.endEditBlock() #--------------------------------------------------------------------------- # 'FrontendWidget' protected interface #--------------------------------------------------------------------------- def _auto_call_tip(self): """Trigger call tip automatically on open parenthesis Call tips can be requested explcitly with `_call_tip`. """ cursor = self._get_cursor() cursor.movePosition(QtGui.QTextCursor.Left) if cursor.document().characterAt(cursor.position()) == '(': # trigger auto call tip on open paren self._call_tip() 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 if not self.enable_calltips or not self.kernel_client.shell_channel.is_alive(): return False cursor_pos = self._get_input_buffer_cursor_pos() code = self.input_buffer # Send the metadata request to the kernel msg_id = self.kernel_client.inspect(code, cursor_pos) pos = self._get_cursor().position() self._request_info['call_tip'] = self._CallTipRequest(msg_id, pos) return True def _complete(self): """ Performs completion at the current cursor location. """ code = self.input_buffer cursor_pos = self._get_input_buffer_cursor_pos() # Send the completion request to the kernel msg_id = self.kernel_client.complete(code=code, cursor_pos=cursor_pos) info = self._CompletionRequest(msg_id, code, cursor_pos) self._request_info['complete'] = info 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'] # If a SystemExit is passed along, this means exit() was called - also # all the ipython %exit magic syntax of '-k' to be used to keep # the kernel running if content['ename']=='SystemExit': keepkernel = content['evalue']=='-k' or content['evalue']=='True' self._keep_kernel_on_exit = keepkernel self.exit_requested.emit(self) else: traceback = ''.join(content['traceback']) self._append_plain_text(traceback) def _process_execute_ok(self, msg): """ Process a reply for a successful execution request. """ payload = msg['content'].get('payload', []) for item in payload: if not self._process_execute_payload(item): warning = 'Warning: received unknown payload of type %s' print(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._auto_call_tip() #------ Trait default initializers ----------------------------------------- @default('banner') def _banner_default(self): """ Returns the standard Python banner. """ banner = 'Python %s on %s\nType "help", "copyright", "credits" or ' \ '"license" for more information.' return banner % (sys.version, sys.platform)