path: root/Lib/idlelib/pyshell.py

#! /usr/bin/env python3

try:
    from tkinter import *
except ImportError:
    print("** IDLE can't import Tkinter.\n"
          "Your Python may not be configured for Tk. **", file=sys.__stderr__)
    sys.exit(1)
import tkinter.messagebox as tkMessageBox
if TkVersion < 8.5:
    root = Tk()  # otherwise create root in main
    root.withdraw()
    tkMessageBox.showerror("Idle Cannot Start",
            "Idle requires tcl/tk 8.5+, not $s." % TkVersion,
            parent=root)
    sys.exit(1)

import getopt
import os
import os.path
import re
import socket
import subprocess
import sys
import threading
import time
import tokenize

import linecache
from code import InteractiveInterpreter
from platform import python_version, system

from idlelib.editor import EditorWindow, fixwordbreaks
from idlelib.filelist import FileList
from idlelib.colorizer import ColorDelegator
from idlelib.undo import UndoDelegator
from idlelib.outwin import OutputWindow
from idlelib.config import idleConf
from idlelib.run import idle_formatwarning, PseudoInputFile, PseudoOutputFile
from idlelib import rpc
from idlelib import debugger
from idlelib import debugger_r
from idlelib import macosx

HOST = '127.0.0.1' # python execution server on localhost loopback
PORT = 0  # someday pass in host, port for remote debug capability

# Override warnings module to write to warning_stream.  Initialize to send IDLE
# internal warnings to the console.  ScriptBinding.check_syntax() will
# temporarily redirect the stream to the shell window to display warnings when
# checking user's code.
warning_stream = sys.__stderr__  # None, at least on Windows, if no console.
import warnings

def idle_showwarning(
        message, category, filename, lineno, file=None, line=None):
    """Show Idle-format warning (after replacing warnings.showwarning).

    The differences are the formatter called, the file=None replacement,
    which can be None, the capture of the consequence AttributeError,
    and the output of a hard-coded prompt.
    """
    if file is None:
        file = warning_stream
    try:
        file.write(idle_formatwarning(
                message, category, filename, lineno, line=line))
        file.write(">>> ")
    except (AttributeError, OSError):
        pass  # if file (probably __stderr__) is invalid, skip warning.

_warnings_showwarning = None

def capture_warnings(capture):
    "Replace warning.showwarning with idle_showwarning, or reverse."

    global _warnings_showwarning
    if capture:
        if _warnings_showwarning is None:
            _warnings_showwarning = warnings.showwarning
            warnings.showwarning = idle_showwarning
    else:
        if _warnings_showwarning is not None:
            warnings.showwarning = _warnings_showwarning
            _warnings_showwarning = None

capture_warnings(True)

def extended_linecache_checkcache(filename=None,
                                  orig_checkcache=linecache.checkcache):
    """Extend linecache.checkcache to preserve the <pyshell#...> entries

    Rather than repeating the linecache code, patch it to save the
    <pyshell#...> entries, call the original linecache.checkcache()
    (skipping them), and then restore the saved entries.

    orig_checkcache is bound at definition time to the original
    method, allowing it to be patched.
    """
    cache = linecache.cache
    save = {}
    for key in list(cache):
        if key[:1] + key[-1:] == '<>':
            save[key] = cache.pop(key)
    orig_checkcache(filename)
    cache.update(save)

# Patch linecache.checkcache():
linecache.checkcache = extended_linecache_checkcache


class PyShellEditorWindow(EditorWindow):
    "Regular text edit window in IDLE, supports breakpoints"

    def __init__(self, *args):
        self.breakpoints = []
        EditorWindow.__init__(self, *args)
        self.text.bind("<<set-breakpoint-here>>", self.set_breakpoint_here)
        self.text.bind("<<clear-breakpoint-here>>", self.clear_breakpoint_here)
        self.text.bind("<<open-python-shell>>", self.flist.open_shell)

        self.breakpointPath = os.path.join(idleConf.GetUserCfgDir(),
                                           'breakpoints.lst')
        # whenever a file is changed, restore breakpoints
        def filename_changed_hook(old_hook=self.io.filename_change_hook,
                                  self=self):
            self.restore_file_breaks()
            old_hook()
        self.io.set_filename_change_hook(filename_changed_hook)
        if self.io.filename:
            self.restore_file_breaks()
        self.color_breakpoint_text()

    rmenu_specs = [
        ("Cut", "<<cut>>", "rmenu_check_cut"),
        ("Copy", "<<copy>>", "rmenu_check_copy"),
        ("Paste", "<<paste>>", "rmenu_check_paste"),
        (None, None, None),
        ("Set Breakpoint", "<<set-breakpoint-here>>", None),
        ("Clear Breakpoint", "<<clear-breakpoint-here>>", None)
    ]

    def color_breakpoint_text(self, color=True):
        "Turn colorizing of breakpoint text on or off"
        if self.io is None:
            # possible due to update in restore_file_breaks
            return
        if color:
            theme = idleConf.CurrentTheme()
            cfg = idleConf.GetHighlight(theme, "break")
        else:
            cfg = {'foreground': '', 'background': ''}
        self.text.tag_config('BREAK', cfg)

    def set_breakpoint(self, lineno):
        text = self.text
        filename = self.io.filename
        text.tag_add("BREAK", "%d.0" % lineno, "%d.0" % (lineno+1))
        try:
            self.breakpoints.index(lineno)
        except ValueError:  # only add if missing, i.e. do once
            self.breakpoints.append(lineno)
        try:    # update the subprocess debugger
            debug = self.flist.pyshell.interp.debugger
            debug.set_breakpoint_here(filename, lineno)
        except: # but debugger may not be active right now....
            pass

    def set_breakpoint_here(self, event=None):
        text = self.text
        filename = self.io.filename
        if not filename:
            text.bell()
            return
        lineno = int(float(text.index("insert")))
        self.set_breakpoint(lineno)

    def clear_breakpoint_here(self, event=None):
        text = self.text
        filename = self.io.filename
        if not filename:
            text.bell()
            return
        lineno = int(float(text.index("insert")))
        try:
            self.breakpoints.remove(lineno)
        except:
            pass
        text.tag_remove("BREAK", "insert linestart",\
                        "insert lineend +1char")
        try:
            debug = self.flist.pyshell.interp.debugger
            debug.clear_breakpoint_here(filename, lineno)
        except:
            pass

    def clear_file_breaks(self):
        if self.breakpoints:
            text = self.text
            filename = self.io.filename
            if not filename:
                text.bell()
                return
            self.breakpoints = []
            text.tag_remove("BREAK", "1.0", END)
            try:
                debug = self.flist.pyshell.interp.debugger
                debug.clear_file_breaks(filename)
            except:
                pass

    def store_file_breaks(self):
        "Save breakpoints when file is saved"
        # XXX 13 Dec 2002 KBK Currently the file must be saved before it can
        #     be run.  The breaks are saved at that time.  If we introduce
        #     a temporary file save feature the save breaks functionality
        #     needs to be re-verified, since the breaks at the time the
        #     temp file is created may differ from the breaks at the last
        #     permanent save of the file.  Currently, a break introduced
        #     after a save will be effective, but not persistent.
        #     This is necessary to keep the saved breaks synched with the
        #     saved file.
        #
        #     Breakpoints are set as tagged ranges in the text.
        #     Since a modified file has to be saved before it is
        #     run, and since self.breakpoints (from which the subprocess
        #     debugger is loaded) is updated during the save, the visible
        #     breaks stay synched with the subprocess even if one of these
        #     unexpected breakpoint deletions occurs.
        breaks = self.breakpoints
        filename = self.io.filename
        try:
            with open(self.breakpointPath, "r") as fp:
                lines = fp.readlines()
        except OSError:
            lines = []
        try:
            with open(self.breakpointPath, "w") as new_file:
                for line in lines:
                    if not line.startswith(filename + '='):
                        new_file.write(line)
                self.update_breakpoints()
                breaks = self.breakpoints
                if breaks:
                    new_file.write(filename + '=' + str(breaks) + '\n')
        except OSError as err:
            if not getattr(self.root, "breakpoint_error_displayed", False):
                self.root.breakpoint_error_displayed = True
                tkMessageBox.showerror(title='IDLE Error',
                    message='Unable to update breakpoint list:\n%s'
                        % str(err),
                    parent=self.text)

    def restore_file_breaks(self):
        self.text.update()   # this enables setting "BREAK" tags to be visible
        if self.io is None:
            # can happen if IDLE closes due to the .update() call
            return
        filename = self.io.filename
        if filename is None:
            return
        if os.path.isfile(self.breakpointPath):
            with open(self.breakpointPath, "r") as fp:
                lines = fp.readlines()
            for line in lines:
                if line.startswith(filename + '='):
                    breakpoint_linenumbers = eval(line[len(filename)+1:])
                    for breakpoint_linenumber in breakpoint_linenumbers:
                        self.set_breakpoint(breakpoint_linenumber)

    def update_breakpoints(self):
        "Retrieves all the breakpoints in the current window"
        text = self.text
        ranges = text.tag_ranges("BREAK")
        linenumber_list = self.ranges_to_linenumbers(ranges)
        self.breakpoints = linenumber_list

    def ranges_to_linenumbers(self, ranges):
        lines = []
        for index in range(0, len(ranges), 2):
            lineno = int(float(ranges[index].string))
            end = int(float(ranges[index+1].string))
            while lineno < end:
                lines.append(lineno)
                lineno += 1
        return lines

# XXX 13 Dec 2002 KBK Not used currently
#    def saved_change_hook(self):
#        "Extend base method - clear breaks if module is modified"
#        if not self.get_saved():
#            self.clear_file_breaks()
#        EditorWindow.saved_change_hook(self)

    def _close(self):
        "Extend base method - clear breaks when module is closed"
        self.clear_file_breaks()
        EditorWindow._close(self)


class PyShellFileList(FileList):
    "Extend base class: IDLE supports a shell and breakpoints"

    # override FileList's class variable, instances return PyShellEditorWindow
    # instead of EditorWindow when new edit windows are created.
    EditorWindow = PyShellEditorWindow

    pyshell = None

    def open_shell(self, event=None):
        if self.pyshell:
            self.pyshell.top.wakeup()
        else:
            self.pyshell = PyShell(self)
            if self.pyshell:
                if not self.pyshell.begin():
                    return None
        return self.pyshell


class ModifiedColorDelegator(ColorDelegator):
    "Extend base class: colorizer for the shell window itself"

    def __init__(self):
        ColorDelegator.__init__(self)
        self.LoadTagDefs()

    def recolorize_main(self):
        self.tag_remove("TODO", "1.0", "iomark")
        self.tag_add("SYNC", "1.0", "iomark")
        ColorDelegator.recolorize_main(self)

    def LoadTagDefs(self):
        ColorDelegator.LoadTagDefs(self)
        theme = idleConf.CurrentTheme()
        self.tagdefs.update({
            "stdin": {'background':None,'foreground':None},
            "stdout": idleConf.GetHighlight(theme, "stdout"),
            "stderr": idleConf.GetHighlight(theme, "stderr"),
            "console": idleConf.GetHighlight(theme, "console"),
        })

    def removecolors(self):
        # Don't remove shell color tags before "iomark"
        for tag in self.tagdefs:
            self.tag_remove(tag, "iomark", "end")

class ModifiedUndoDelegator(UndoDelegator):
    "Extend base class: forbid insert/delete before the I/O mark"

    def insert(self, index, chars, tags=None):
        try:
            if self.delegate.compare(index, "<", "iomark"):
                self.delegate.bell()
                return
        except TclError:
            pass
        UndoDelegator.insert(self, index, chars, tags)

    def delete(self, index1, index2=None):
        try:
            if self.delegate.compare(index1, "<", "iomark"):
                self.delegate.bell()
                return
        except TclError:
            pass
        UndoDelegator.delete(self, index1, index2)


class MyRPCClient(rpc.RPCClient):

    def handle_EOF(self):
        "Override the base class - just re-raise EOFError"
        raise EOFError


class ModifiedInterpreter(InteractiveInterpreter):

    def __init__(self, tkconsole):
        self.tkconsole = tkconsole
        locals = sys.modules['__main__'].__dict__
        InteractiveInterpreter.__init__(self, locals=locals)
        self.save_warnings_filters = None
        self.restarting = False
        self.subprocess_arglist = None
        self.port = PORT
        self.original_compiler_flags = self.compile.compiler.flags

    _afterid = None
    rpcclt = None
    rpcsubproc = None

    def spawn_subprocess(self):
        if self.subprocess_arglist is None:
            self.subprocess_arglist = self.build_subprocess_arglist()
        self.rpcsubproc = subprocess.Popen(self.subprocess_arglist)

    def build_subprocess_arglist(self):
        assert (self.port!=0), (
            "Socket should have been assigned a port number.")
        w = ['-W' + s for s in sys.warnoptions]
        # Maybe IDLE is installed and is being accessed via sys.path,
        # or maybe it's not installed and the idle.py script is being
        # run from the IDLE source directory.
        del_exitf = idleConf.GetOption('main', 'General', 'delete-exitfunc',
                                       default=False, type='bool')
        if __name__ == 'idlelib.pyshell':
            command = "__import__('idlelib.run').run.main(%r)" % (del_exitf,)
        else:
            command = "__import__('run').main(%r)" % (del_exitf,)
        return [sys.executable] + w + ["-c", command, str(self.port)]

    def start_subprocess(self):
        addr = (HOST, self.port)
        # GUI makes several attempts to acquire socket, listens for connection
        for i in range(3):
            time.sleep(i)
            try:
                self.rpcclt = MyRPCClient(addr)
                break
            except OSError:
                pass
        else:
            self.display_port_binding_error()
            return None
        # if PORT was 0, system will assign an 'ephemeral' port. Find it out:
        self.port = self.rpcclt.listening_sock.getsockname()[1]
        # if PORT was not 0, probably working with a remote execution server
        if PORT != 0:
            # To allow reconnection within the 2MSL wait (cf. Stevens TCP
            # V1, 18.6),  set SO_REUSEADDR.  Note that this can be problematic
            # on Windows since the implementation allows two active sockets on
            # the same address!
            self.rpcclt.listening_sock.setsockopt(socket.SOL_SOCKET,
                                           socket.SO_REUSEADDR, 1)
        self.spawn_subprocess()
        #time.sleep(20) # test to simulate GUI not accepting connection
        # Accept the connection from the Python execution server
        self.rpcclt.listening_sock.settimeout(10)
        try:
            self.rpcclt.accept()
        except socket.timeout:
            self.display_no_subprocess_error()
            return None
        self.rpcclt.register("console", self.tkconsole)
        self.rpcclt.register("stdin", self.tkconsole.stdin)
        self.rpcclt.register("stdout", self.tkconsole.stdout)
        self.rpcclt.register("stderr", self.tkconsole.stderr)
        self.rpcclt.register("flist", self.tkconsole.flist)
        self.rpcclt.register("linecache", linecache)
        self.rpcclt.register("interp", self)
        self.transfer_path(with_cwd=True)
        self.poll_subprocess()
        return self.rpcclt

    def restart_subprocess(self, with_cwd=False, filename=''):
        if self.restarting:
            return self.rpcclt
        self.restarting = True
        # close only the subprocess debugger
        debug = self.getdebugger()
        if debug:
            try:
                # Only close subprocess debugger, don't unregister gui_adap!
                debugger_r.close_subprocess_debugger(self.rpcclt)
            except:
                pass
        # Kill subprocess, spawn a new one, accept connection.
        self.rpcclt.close()
        self.terminate_subprocess()
        console = self.tkconsole
        was_executing = console.executing
        console.executing = False
        self.spawn_subprocess()
        try:
            self.rpcclt.accept()
        except socket.timeout:
            self.display_no_subprocess_error()
            return None
        self.transfer_path(with_cwd=with_cwd)
        console.stop_readline()
        # annotate restart in shell window and mark it
        console.text.delete("iomark", "end-1c")
        tag = 'RESTART: ' + (filename if filename else 'Shell')
        halfbar = ((int(console.width) -len(tag) - 4) // 2) * '='
        console.write("\n{0} {1} {0}".format(halfbar, tag))
        console.text.mark_set("restart", "end-1c")
        console.text.mark_gravity("restart", "left")
        if not filename:
            console.showprompt()
        # restart subprocess debugger
        if debug:
            # Restarted debugger connects to current instance of debug GUI
            debugger_r.restart_subprocess_debugger(self.rpcclt)
            # reload remote debugger breakpoints for all PyShellEditWindows
            debug.load_breakpoints()
        self.compile.compiler.flags = self.original_compiler_flags
        self.restarting = False
        return self.rpcclt

    def __request_interrupt(self):
        self.rpcclt.remotecall("exec", "interrupt_the_server", (), {})

    def interrupt_subprocess(self):
        threading.Thread(target=self.__request_interrupt).start()

    def kill_subprocess(self):
        if self._afterid is not None:
            self.tkconsole.text.after_cancel(self._afterid)
        try:
            self.rpcclt.listening_sock.close()
        except AttributeError:  # no socket
            pass
        try:
            self.rpcclt.close()
        except AttributeError:  # no socket
            pass
        self.terminate_subprocess()
        self.tkconsole.executing = False
        self.rpcclt = None

    def terminate_subprocess(self):
        "Make sure subprocess is terminated"
        try:
            self.rpcsubproc.kill()
        except OSError:
            # process already terminated
            return
        else:
            try:
                self.rpcsubproc.wait()
            except OSError:
                return

    def transfer_path(self, with_cwd=False):
        if with_cwd:        # Issue 13506
            path = ['']     # include Current Working Directory
            path.extend(sys.path)
        else:
            path = sys.path

        self.runcommand("""if 1:
        import sys as _sys
        _sys.path = %r
        del _sys
        \n""" % (path,))

    active_seq = None

    def poll_subprocess(self):
        clt = self.rpcclt
        if clt is None:
            return
        try:
            response = clt.pollresponse(self.active_seq, wait=0.05)
        except (EOFError, OSError, KeyboardInterrupt):
            # lost connection or subprocess terminated itself, restart
            # [the KBI is from rpc.SocketIO.handle_EOF()]
            if self.tkconsole.closing:
                return
            response = None
            self.restart_subprocess()
        if response:
            self.tkconsole.resetoutput()
            self.active_seq = None
            how, what = response
            console = self.tkconsole.console
            if how == "OK":
                if what is not None:
                    print(repr(what), file=console)
            elif how == "EXCEPTION":
                if self.tkconsole.getvar("<<toggle-jit-stack-viewer>>"):
                    self.remote_stack_viewer()
            elif how == "ERROR":
                errmsg = "pyshell.ModifiedInterpreter: Subprocess ERROR:\n"
                print(errmsg, what, file=sys.__stderr__)
                print(errmsg, what, file=console)
            # we received a response to the currently active seq number:
            try:
                self.tkconsole.endexecuting()
            except AttributeError:  # shell may have closed
                pass
        # Reschedule myself
        if not self.tkconsole.closing:
            self._afterid = self.tkconsole.text.after(
                self.tkconsole.pollinterval, self.poll_subprocess)

    debugger = None

    def setdebugger(self, debugger):
        self.debugger = debugger

    def getdebugger(self):
        return self.debugger

    def open_remote_stack_viewer(self):
        """Initiate the remote stack viewer from a separate thread.

        This method is called from the subprocess, and by returning from this
        method we allow the subprocess to unblock.  After a bit the shell
        requests the subprocess to open the remote stack viewer which returns a
        static object looking at the last exception.  It is queried through
        the RPC mechanism.

        """
        self.tkconsole.text.after(300, self.remote_stack_viewer)
        return

    def remote_stack_viewer(self):
        from idlelib import debugobj_r
        oid = self.rpcclt.remotequeue("exec", "stackviewer", ("flist",), {})
        if oid is None:
            self.tkconsole.root.bell()
            return
        item = debugobj_r.StubObjectTreeItem(self.rpcclt, oid)
        from idlelib.tree import ScrolledCanvas, TreeNode
        top = Toplevel(self.tkconsole.root)
        theme = idleConf.CurrentTheme()
        background = idleConf.GetHighlight(theme, 'normal')['background']
        sc = ScrolledCanvas(top, bg=background, highlightthickness=0)
        sc.frame.pack(expand=1, fill="both")
        node = TreeNode(sc.canvas, None, item)
        node.expand()
        # XXX Should GC the remote tree when closing the window

    gid = 0

    def execsource(self, source):
        "Like runsource() but assumes complete exec source"
        filename = self.stuffsource(source)
        self.execfile(filename, source)

    def execfile(self, filename, source=None):
        "Execute an existing file"
        if source is None:
            with tokenize.open(filename) as fp:
                source = fp.read()
        try:
            code = compile(source, filename, "exec")
        except (OverflowError, SyntaxError):
            self.tkconsole.resetoutput()
            print('*** Error in script or command!\n'
                 'Traceback (most recent call last):',
                  file=self.tkconsole.stderr)
            InteractiveInterpreter.showsyntaxerror(self, filename)
            self.tkconsole.showprompt()
        else:
            self.runcode(code)

    def runsource(self, source):
        "Extend base class method: Stuff the source in the line cache first"
        filename = self.stuffsource(source)
        self.more = 0
        self.save_warnings_filters = warnings.filters[:]
        warnings.filterwarnings(action="error", category=SyntaxWarning)
        # at the moment, InteractiveInterpreter expects str
        assert isinstance(source, str)
        #if isinstance(source, str):
        #    from idlelib import iomenu
        #    try:
        #        source = source.encode(iomenu.encoding)
        #    except UnicodeError:
        #        self.tkconsole.resetoutput()
        #        self.write("Unsupported characters in input\n")
        #        return
        try:
            # InteractiveInterpreter.runsource() calls its runcode() method,
            # which is overridden (see below)
            return InteractiveInterpreter.runsource(self, source, filename)
        finally:
            if self.save_warnings_filters is not None:
                warnings.filters[:] = self.save_warnings_filters
                self.save_warnings_filters = None

    def stuffsource(self, source):
        "Stuff source in the filename cache"
        filename = "<pyshell#%d>" % self.gid
        self.gid = self.gid + 1
        lines = source.split("\n")
        linecache.cache[filename] = len(source)+1, 0, lines, filename
        return filename

    def prepend_syspath(self, filename):
        "Prepend sys.path with file's directory if not already included"
        self.runcommand("""if 1:
            _filename = %r
            import sys as _sys
            from os.path import dirname as _dirname
            _dir = _dirname(_filename)
            if not _dir in _sys.path:
                _sys.path.insert(0, _dir)
            del _filename, _sys, _dirname, _dir
            \n""" % (filename,))

    def showsyntaxerror(self, filename=None):
        """Override Interactive Interpreter method: Use Colorizing

        Color the offending position instead of printing it and pointing at it
        with a caret.

        """
        tkconsole = self.tkconsole
        text = tkconsole.text
        text.tag_remove("ERROR", "1.0", "end")
        type, value, tb = sys.exc_info()
        msg = getattr(value, 'msg', '') or value or "<no detail available>"
        lineno = getattr(value, 'lineno', '') or 1
        offset = getattr(value, 'offset', '') or 0
        if offset == 0:
            lineno += 1 #mark end of offending line
        if lineno == 1:
            pos = "iomark + %d chars" % (offset-1)
        else:
            pos = "iomark linestart + %d lines + %d chars" % \
                  (lineno-1, offset-1)
        tkconsole.colorize_syntax_error(text, pos)
        tkconsole.resetoutput()
        self.write("SyntaxError: %s\n" % msg)
        tkconsole.showprompt()

    def showtraceback(self):
        "Extend base class method to reset output properly"
        self.tkconsole.resetoutput()
        self.checklinecache()
        InteractiveInterpreter.showtraceback(self)
        if self.tkconsole.getvar("<<toggle-jit-stack-viewer>>"):
            self.tkconsole.open_stack_viewer()

    def checklinecache(self):
        c = linecache.cache
        for key in list(c.keys()):
            if key[:1] + key[-1:] != "<>":
                del c[key]

    def runcommand(self, code):
        "Run the code without invoking the debugger"
        # The code better not raise an exception!
        if self.tkconsole.executing:
            self.display_executing_dialog()
            return 0
        if self.rpcclt:
            self.rpcclt.remotequeue("exec", "runcode", (code,), {})
        else:
            exec(code, self.locals)
        return 1

    def runcode(self, code):
        "Override base class method"
        if self.tkconsole.executing:
            self.interp.restart_subprocess()
        self.checklinecache()
        if self.save_warnings_filters is not None:
            warnings.filters[:] = self.save_warnings_filters
            self.save_warnings_filters = None
        debugger = self.debugger
        try:
            self.tkconsole.beginexecuting()
            if not debugger and self.rpcclt is not None:
                self.active_seq = self.rpcclt.asyncqueue("exec", "runcode",
                                                        (code,), {})
            elif debugger:
                debugger.run(code, self.locals)
            else:
                exec(code, self.locals)
        except SystemExit:
            if not self.tkconsole.closing:
                if tkMessageBox.askyesno(
                    "Exit?",
                    "Do you want to exit altogether?",
                    default="yes",
                    parent=self.tkconsole.text):
                    raise
                else:
                    self.showtraceback()
            else:
                raise
        except:
            if use_subprocess:
                print("IDLE internal error in runcode()",
                      file=self.tkconsole.stderr)
                self.showtraceback()
                self.tkconsole.endexecuting()
            else:
                if self.tkconsole.canceled:
                    self.tkconsole.canceled = False
                    print("KeyboardInterrupt", file=self.tkconsole.stderr)
                else:
                    self.showtraceback()
        finally:
            if not use_subprocess:
                try:
                    self.tkconsole.endexecuting()
                except AttributeError:  # shell may have closed
                    pass

    def write(self, s):
        "Override base class method"
        return self.tkconsole.stderr.write(s)

    def display_port_binding_error(self):
        tkMessageBox.showerror(
            "Port Binding Error",
            "IDLE can't bind to a TCP/IP port, which is necessary to "
            "communicate with its Python execution server.  This might be "
            "because no networking is installed on this computer.  "
            "Run IDLE with the -n command line switch to start without a "
            "subprocess and refer to Help/IDLE Help 'Running without a "
            "subprocess' for further details.",
            parent=self.tkconsole.text)

    def display_no_subprocess_error(self):
        tkMessageBox.showerror(
            "Subprocess Startup Error",
            "IDLE's subprocess didn't make connection.  Either IDLE can't "
            "start a subprocess or personal firewall software is blocking "
            "the connection.",
            parent=self.tkconsole.text)

    def display_executing_dialog(self):
        tkMessageBox.showerror(
            "Already executing",
            "The Python Shell window is already executing a command; "
            "please wait until it is finished.",
            parent=self.tkconsole.text)


class PyShell(OutputWindow):

    shell_title = "Python " + python_version() + " Shell"

    # Override classes
    ColorDelegator = ModifiedColorDelegator
    UndoDelegator = ModifiedUndoDelegator

    # Override menus
    menu_specs = [
        ("file", "_File"),
        ("edit", "_Edit"),
        ("debug", "_Debug"),
        ("options", "_Options"),
        ("windows", "_Window"),
        ("help", "_Help"),
    ]


    # New classes
    from idlelib.history import History

    def __init__(self, flist=None):
        if use_subprocess:
            ms = self.menu_specs
            if ms[2][0] != "shell":
                ms.insert(2, ("shell", "She_ll"))
        self.interp = ModifiedInterpreter(self)
        if flist is None:
            root = Tk()
            fixwordbreaks(root)
            root.withdraw()
            flist = PyShellFileList(root)
        #
        OutputWindow.__init__(self, flist, None, None)
        #
##        self.config(usetabs=1, indentwidth=8, context_use_ps1=1)
        self.usetabs = True
        # indentwidth must be 8 when using tabs.  See note in EditorWindow:
        self.indentwidth = 8
        self.context_use_ps1 = True
        #
        text = self.text
        text.configure(wrap="char")
        text.bind("<<newline-and-indent>>", self.enter_callback)
        text.bind("<<plain-newline-and-indent>>", self.linefeed_callback)
        text.bind("<<interrupt-execution>>", self.cancel_callback)
        text.bind("<<end-of-file>>", self.eof_callback)
        text.bind("<<open-stack-viewer>>", self.open_stack_viewer)
        text.bind("<<toggle-debugger>>", self.toggle_debugger)
        text.bind("<<toggle-jit-stack-viewer>>", self.toggle_jit_stack_viewer)
        if use_subprocess:
            text.bind("<<view-restart>>", self.view_restart_mark)
            text.bind("<<restart-shell>>", self.restart_shell)
        #
        self.save_stdout = sys.stdout
        self.save_stderr = sys.stderr
        self.save_stdin = sys.stdin
        from idlelib import iomenu
        self.stdin = PseudoInputFile(self, "stdin", iomenu.encoding)
        self.stdout = PseudoOutputFile(self, "stdout", iomenu.encoding)
        self.stderr = PseudoOutputFile(self, "stderr", iomenu.encoding)
        self.console = PseudoOutputFile(self, "console", iomenu.encoding)
        if not use_subprocess:
            sys.stdout = self.stdout
            sys.stderr = self.stderr
            sys.stdin = self.stdin
        try:
            # page help() text to shell.
            import pydoc # import must be done here to capture i/o rebinding.
            # XXX KBK 27Dec07 use TextViewer someday, but must work w/o subproc
            pydoc.pager = pydoc.plainpager
        except:
            sys.stderr = sys.__stderr__
            raise
        #
        self.history = self.History(self.text)
        #
        self.pollinterval = 50  # millisec

    def get_standard_extension_names(self):
        return idleConf.GetExtensions(shell_only=True)

    reading = False
    executing = False
    canceled = False
    endoffile = False
    closing = False
    _stop_readline_flag = False

    def set_warning_stream(self, stream):
        global warning_stream
        warning_stream = stream

    def get_warning_stream(self):
        return warning_stream

    def toggle_debugger(self, event=None):
        if self.executing:
            tkMessageBox.showerror("Don't debug now",
                "You can only toggle the debugger when idle",
                parent=self.text)
            self.set_debugger_indicator()
            return "break"
        else:
            db = self.interp.getdebugger()
            if db:
                self.close_debugger()
            else:
                self.open_debugger()

    def set_debugger_indicator(self):
        db = self.interp.getdebugger()
        self.setvar("<<toggle-debugger>>", not not db)

    def toggle_jit_stack_viewer(self, event=None):
        pass # All we need is the variable

    def close_debugger(self):
        db = self.interp.getdebugger()
        if db:
            self.interp.setdebugger(None)
            db.close()
            if self.interp.rpcclt:
                debugger_r.close_remote_debugger(self.interp.rpcclt)
            self.resetoutput()
            self.console.write("[DEBUG OFF]\n")
            sys.ps1 = ">>> "
            self.showprompt()
        self.set_debugger_indicator()

    def open_debugger(self):
        if self.interp.rpcclt:
            dbg_gui = debugger_r.start_remote_debugger(self.interp.rpcclt,
                                                           self)
        else:
            dbg_gui = debugger.Debugger(self)
        self.interp.setdebugger(dbg_gui)
        dbg_gui.load_breakpoints()
        sys.ps1 = "[DEBUG ON]\n>>> "
        self.showprompt()
        self.set_debugger_indicator()

    def beginexecuting(self):
        "Helper for ModifiedInterpreter"
        self.resetoutput()
        self.executing = 1

    def endexecuting(self):
        "Helper for ModifiedInterpreter"
        self.executing = 0
        self.canceled = 0
        self.showprompt()

    def close(self):
        "Extend EditorWindow.close()"
        if self.executing:
            response = tkMessageBox.askokcancel(
                "Kill?",
                "Your program is still running!\n Do you want to kill it?",
                default="ok",
                parent=self.text)
            if response is False:
                return "cancel"
        self.stop_readline()
        self.canceled = True
        self.closing = True
        return EditorWindow.close(self)

    def _close(self):
        "Extend EditorWindow._close(), shut down debugger and execution server"
        self.close_debugger()
        if use_subprocess:
            self.interp.kill_subprocess()
        # Restore std streams
        sys.stdout = self.save_stdout
        sys.stderr = self.save_stderr
        sys.stdin = self.save_stdin
        # Break cycles
        self.interp = None
        self.console = None
        self.flist.pyshell = None
        self.history = None
        EditorWindow._close(self)

    def ispythonsource(self, filename):
        "Override EditorWindow method: never remove the colorizer"
        return True

    def short_title(self):
        return self.shell_title

    COPYRIGHT = \
          'Type "copyright", "credits" or "license()" for more information.'

    def begin(self):
        self.text.mark_set("iomark", "insert")
        self.resetoutput()
        if use_subprocess:
            nosub = ''
            client = self.interp.start_subprocess()
            if not client:
                self.close()
                return False
        else:
            nosub = ("==== No Subprocess ====\n\n" +
                    "WARNING: Running IDLE without a Subprocess is deprecated\n" +
                    "and will be removed in a later version. See Help/IDLE Help\n" +
                    "for details.\n\n")
            sys.displayhook = rpc.displayhook

        self.write("Python %s on %s\n%s\n%s" %
                   (sys.version, sys.platform, self.COPYRIGHT, nosub))
        self.text.focus_force()
        self.showprompt()
        import tkinter
        tkinter._default_root = None # 03Jan04 KBK What's this?
        return True

    def stop_readline(self):
        if not self.reading:  # no nested mainloop to exit.
            return
        self._stop_readline_flag = True
        self.top.quit()

    def readline(self):
        save = self.reading
        try:
            self.reading = 1
            self.top.mainloop()  # nested mainloop()
        finally:
            self.reading = save
        if self._stop_readline_flag:
            self._stop_readline_flag = False
            return ""
        line = self.text.get("iomark", "end-1c")
        if len(line) == 0:  # may be EOF if we quit our mainloop with Ctrl-C
            line = "\n"
        self.resetoutput()
        if self.canceled:
            self.canceled = 0
            if not use_subprocess:
                raise KeyboardInterrupt
        if self.endoffile:
            self.endoffile = 0
            line = ""
        return line

    def isatty(self):
        return True

    def cancel_callback(self, event=None):
        try:
            if self.text.compare("sel.first", "!=", "sel.last"):
                return # Active selection -- always use default binding
        except:
            pass
        if not (self.executing or self.reading):
            self.resetoutput()
            self.interp.write("KeyboardInterrupt\n")
            self.showprompt()
            return "break"
        self.endoffile = 0
        self.canceled = 1
        if (self.executing and self.interp.rpcclt):
            if self.interp.getdebugger():
                self.interp.restart_subprocess()
            else:
                self.interp.interrupt_subprocess()
        if self.reading:
            self.top.quit()  # exit the nested mainloop() in readline()
        return "break"

    def eof_callback(self, event):
        if self.executing and not self.reading:
            return # Let the default binding (delete next char) take over
        if not (self.text.compare("iomark", "==", "insert") and
                self.text.compare("insert", "==", "end-1c")):
            return # Let the default binding (delete next char) take over
        if not self.executing:
            self.resetoutput()
            self.close()
        else:
            self.canceled = 0
            self.endoffile = 1
            self.top.quit()
        return "break"

    def linefeed_callback(self, event):
        # Insert a linefeed without entering anything (still autoindented)
        if self.reading:
            self.text.insert("insert", "\n")
            self.text.see("insert")
        else:
            self.newline_and_indent_event(event)
        return "break"

    def enter_callback(self, event):
        if self.executing and not self.reading:
            return # Let the default binding (insert '\n') take over
        # If some text is selected, recall the selection
        # (but only if this before the I/O mark)
        try:
            sel = self.text.get("sel.first", "sel.last")
            if sel:
                if self.text.compare("sel.last", "<=", "iomark"):
                    self.recall(sel, event)
                    return "break"
        except:
            pass
        # If we're strictly before the line containing iomark, recall
        # the current line, less a leading prompt, less leading or
        # trailing whitespace
        if self.text.compare("insert", "<", "iomark linestart"):
            # Check if there's a relevant stdin range -- if so, use it
            prev = self.text.tag_prevrange("stdin", "insert")
            if prev and self.text.compare("insert", "<", prev[1]):
                self.recall(self.text.get(prev[0], prev[1]), event)
                return "break"
            next = self.text.tag_nextrange("stdin", "insert")
            if next and self.text.compare("insert lineend", ">=", next[0]):
                self.recall(self.text.get(next[0], next[1]), event)
                return "break"
            # No stdin mark -- just get the current line, less any prompt
            indices = self.text.tag_nextrange("console", "insert linestart")
            if indices and \
               self.text.compare(indices[0], "<=", "insert linestart"):
                self.recall(self.text.get(indices[1], "insert lineend"), event)
            else:
                self.recall(self.text.get("insert linestart", "insert lineend"), event)
            return "break"
        # If we're between the beginning of the line and the iomark, i.e.
        # in the prompt area, move to the end of the prompt
        if self.text.compare("insert", "<", "iomark"):
            self.text.mark_set("insert", "iomark")
        # If we're in the current input and there's only whitespace
        # beyond the cursor, erase that whitespace first
        s = self.text.get("insert", "end-1c")
        if s and not s.strip():
            self.text.delete("insert", "end-1c")
        # If we're in the current input before its last line,
        # insert a newline right at the insert point
        if self.text.compare("insert", "<", "end-1c linestart"):
            self.newline_and_indent_event(event)
            return "break"
        # We're in the last line; append a newline and submit it
        self.text.mark_set("insert", "end-1c")
        if self.reading:
            self.text.insert("insert", "\n")
            self.text.see("insert")
        else:
            self.newline_and_indent_event(event)
        self.text.tag_add("stdin", "iomark", "end-1c")
        self.text.update_idletasks()
        if self.reading:
            self.top.quit() # Break out of recursive mainloop()
        else:
            self.runit()
        return "break"

    def recall(self, s, event):
        # remove leading and trailing empty or whitespace lines
        s = re.sub(r'^\s*\n', '' , s)
        s = re.sub(r'\n\s*$', '', s)
        lines = s.split('\n')
        self.text.undo_block_start()
        try:
            self.text.tag_remove("sel", "1.0", "end")
            self.text.mark_set("insert", "end-1c")
            prefix = self.text.get("insert linestart", "insert")
            if prefix.rstrip().endswith(':'):
                self.newline_and_indent_event(event)
                prefix = self.text.get("insert linestart", "insert")
            self.text.insert("insert", lines[0].strip())
            if len(lines) > 1:
                orig_base_indent = re.search(r'^([ \t]*)', lines[0]).group(0)
                new_base_indent  = re.search(r'^([ \t]*)', prefix).group(0)
                for line in lines[1:]:
                    if line.startswith(orig_base_indent):
                        # replace orig base indentation with new indentation
                        line = new_base_indent + line[len(orig_base_indent):]
                    self.text.insert('insert', '\n'+line.rstrip())
        finally:
            self.text.see("insert")
            self.text.undo_block_stop()

    def runit(self):
        line = self.text.get("iomark", "end-1c")
        # Strip off last newline and surrounding whitespace.
        # (To allow you to hit return twice to end a statement.)
        i = len(line)
        while i > 0 and line[i-1] in " \t":
            i = i-1
        if i > 0 and line[i-1] == "\n":
            i = i-1
        while i > 0 and line[i-1] in " \t":
            i = i-1
        line = line[:i]
        self.interp.runsource(line)

    def open_stack_viewer(self, event=None):
        if self.interp.rpcclt:
            return self.interp.remote_stack_viewer()
        try:
            sys.last_traceback
        except:
            tkMessageBox.showerror("No stack trace",
                "There is no stack trace yet.\n"
                "(sys.last_traceback is not defined)",
                parent=self.text)
            return
        from idlelib.stackviewer import StackBrowser
        StackBrowser(self.root, self.flist)

    def view_restart_mark(self, event=None):
        self.text.see("iomark")
        self.text.see("restart")

    def restart_shell(self, event=None):
        "Callback for Run/Restart Shell Cntl-F6"
        self.interp.restart_subprocess(with_cwd=True)

    def showprompt(self):
        self.resetoutput()
        try:
            s = str(sys.ps1)
        except:
            s = ""
        self.console.write(s)
        self.text.mark_set("insert", "end-1c")
        self.set_line_and_column()
        self.io.reset_undo()

    def resetoutput(self):
        source = self.text.get("iomark", "end-1c")
        if self.history:
            self.history.store(source)
        if self.text.get("end-2c") != "\n":
            self.text.insert("end-1c", "\n")
        self.text.mark_set("iomark", "end-1c")
        self.set_line_and_column()

    def write(self, s, tags=()):
        if isinstance(s, str) and len(s) and max(s) > '\uffff':
            # Tk doesn't support outputting non-BMP characters
            # Let's assume what printed string is not very long,
            # find first non-BMP character and construct informative
            # UnicodeEncodeError exception.
            for start, char in enumerate(s):
                if char > '\uffff':
                    break
            raise UnicodeEncodeError("UCS-2", char, start, start+1,
                                     'Non-BMP character not supported in Tk')
        try:
            self.text.mark_gravity("iomark", "right")
            count = OutputWindow.write(self, s, tags, "iomark")
            self.text.mark_gravity("iomark", "left")
        except:
            raise ###pass  # ### 11Aug07 KBK if we are expecting exceptions
                           # let's find out what they are and be specific.
        if self.canceled:
            self.canceled = 0
            if not use_subprocess:
                raise KeyboardInterrupt
        return count

    def rmenu_check_cut(self):
        try:
            if self.text.compare('sel.first', '<', 'iomark'):
                return 'disabled'
        except TclError: # no selection, so the index 'sel.first' doesn't exist
            return 'disabled'
        return super().rmenu_check_cut()

    def rmenu_check_paste(self):
        if self.text.compare('insert','<','iomark'):
            return 'disabled'
        return super().rmenu_check_paste()


def fix_x11_paste(root):
    "Make paste replace selection on x11.  See issue #5124."
    if root._windowingsystem == 'x11':
        for cls in 'Text', 'Entry', 'Spinbox':
            root.bind_class(
                cls,
                '<<Paste>>',
                'catch {%W delete sel.first sel.last}\n' +
                        root.bind_class(cls, '<<Paste>>'))


usage_msg = """\

USAGE: idle  [-deins] [-t title] [file]*
       idle  [-dns] [-t title] (-c cmd | -r file) [arg]*
       idle  [-dns] [-t title] - [arg]*

  -h         print this help message and exit
  -n         run IDLE without a subprocess (DEPRECATED,
             see Help/IDLE Help for details)

The following options will override the IDLE 'settings' configuration:

  -e         open an edit window
  -i         open a shell window

The following options imply -i and will open a shell:

  -c cmd     run the command in a shell, or
  -r file    run script from file

  -d         enable the debugger
  -s         run $IDLESTARTUP or $PYTHONSTARTUP before anything else
  -t title   set title of shell window

A default edit window will be bypassed when -c, -r, or - are used.

[arg]* are passed to the command (-c) or script (-r) in sys.argv[1:].

Examples:

idle
        Open an edit window or shell depending on IDLE's configuration.

idle foo.py foobar.py
        Edit the files, also open a shell if configured to start with shell.

idle -est "Baz" foo.py
        Run $IDLESTARTUP or $PYTHONSTARTUP, edit foo.py, and open a shell
        window with the title "Baz".

idle -c "import sys; print(sys.argv)" "foo"
        Open a shell window and run the command, passing "-c" in sys.argv[0]
        and "foo" in sys.argv[1].

idle -d -s -r foo.py "Hello World"
        Open a shell window, run a startup script, enable the debugger, and
        run foo.py, passing "foo.py" in sys.argv[0] and "Hello World" in
        sys.argv[1].

echo "import sys; print(sys.argv)" | idle - "foobar"
        Open a shell window, run the script piped in, passing '' in sys.argv[0]
        and "foobar" in sys.argv[1].
"""

def main():
    global flist, root, use_subprocess

    capture_warnings(True)
    use_subprocess = True
    enable_shell = False
    enable_edit = False
    debug = False
    cmd = None
    script = None
    startup = False
    try:
        opts, args = getopt.getopt(sys.argv[1:], "c:deihnr:st:")
    except getopt.error as msg:
        print("Error: %s\n%s" % (msg, usage_msg), file=sys.stderr)
        sys.exit(2)
    for o, a in opts:
        if o == '-c':
            cmd = a
            enable_shell = True
        if o == '-d':
            debug = True
            enable_shell = True
        if o == '-e':
            enable_edit = True
        if o == '-h':
            sys.stdout.write(usage_msg)
            sys.exit()
        if o == '-i':
            enable_shell = True
        if o == '-n':
            print(" Warning: running IDLE without a subprocess is deprecated.",
                  file=sys.stderr)
            use_subprocess = False
        if o == '-r':
            script = a
            if os.path.isfile(script):
                pass
            else:
                print("No script file: ", script)
                sys.exit()
            enable_shell = True
        if o == '-s':
            startup = True
            enable_shell = True
        if o == '-t':
            PyShell.shell_title = a
            enable_shell = True
    if args and args[0] == '-':
        cmd = sys.stdin.read()
        enable_shell = True
    # process sys.argv and sys.path:
    for i in range(len(sys.path)):
        sys.path[i] = os.path.abspath(sys.path[i])
    if args and args[0] == '-':
        sys.argv = [''] + args[1:]
    elif cmd:
        sys.argv = ['-c'] + args
    elif script:
        sys.argv = [script] + args
    elif args:
        enable_edit = True
        pathx = []
        for filename in args:
            pathx.append(os.path.dirname(filename))
        for dir in pathx:
            dir = os.path.abspath(dir)
            if not dir in sys.path:
                sys.path.insert(0, dir)
    else:
        dir = os.getcwd()
        if dir not in sys.path:
            sys.path.insert(0, dir)
    # check the IDLE settings configuration (but command line overrides)
    edit_start = idleConf.GetOption('main', 'General',
                                    'editor-on-startup', type='bool')
    enable_edit = enable_edit or edit_start
    enable_shell = enable_shell or not enable_edit

    # Setup root.
    if use_subprocess:  # Don't break user code run in IDLE process
        NoDefaultRoot()
    root = Tk(className="Idle")
    root.withdraw()

    # set application icon
    icondir = os.path.join(os.path.dirname(__file__), 'Icons')
    if system() == 'Windows':
        iconfile = os.path.join(icondir, 'idle.ico')
        root.wm_iconbitmap(default=iconfile)
    else:
        ext = '.png' if TkVersion >= 8.6 else '.gif'
        iconfiles = [os.path.join(icondir, 'idle_%d%s' % (size, ext))
                     for size in (16, 32, 48)]
        icons = [PhotoImage(master=root, file=iconfile)
                 for iconfile in iconfiles]
        root.wm_iconphoto(True, *icons)

    # start editor and/or shell windows:
    fixwordbreaks(root)
    fix_x11_paste(root)
    flist = PyShellFileList(root)
    macosx.setupApp(root, flist)

    if enable_edit:
        if not (cmd or script):
            for filename in args[:]:
                if flist.open(filename) is None:
                    # filename is a directory actually, disconsider it
                    args.remove(filename)
            if not args:
                flist.new()

    if enable_shell:
        shell = flist.open_shell()
        if not shell:
            return # couldn't open shell
        if macosx.isAquaTk() and flist.dict:
            # On OSX: when the user has double-clicked on a file that causes
            # IDLE to be launched the shell window will open just in front of
            # the file she wants to see. Lower the interpreter window when
            # there are open files.
            shell.top.lower()
    else:
        shell = flist.pyshell

    # Handle remaining options. If any of these are set, enable_shell
    # was set also, so shell must be true to reach here.
    if debug:
        shell.open_debugger()
    if startup:
        filename = os.environ.get("IDLESTARTUP") or \
                   os.environ.get("PYTHONSTARTUP")
        if filename and os.path.isfile(filename):
            shell.interp.execfile(filename)
    if cmd or script:
        shell.interp.runcommand("""if 1:
            import sys as _sys
            _sys.argv = %r
            del _sys
            \n""" % (sys.argv,))
        if cmd:
            shell.interp.execsource(cmd)
        elif script:
            shell.interp.prepend_syspath(script)
            shell.interp.execfile(script)
    elif shell:
        # If there is a shell window and no cmd or script in progress,
        # check for problematic OS X Tk versions and print a warning
        # message in the IDLE shell window; this is less intrusive
        # than always opening a separate window.
        tkversionwarning = macosx.tkVersionWarning(root)
        if tkversionwarning:
            shell.interp.runcommand("print('%s')" % tkversionwarning)

    while flist.inversedict:  # keep IDLE running while files are open.
        root.mainloop()
    root.destroy()
    capture_warnings(False)

if __name__ == "__main__":
    sys.modules['pyshell'] = sys.modules['__main__']
    main()

capture_warnings(False)  # Make sure turned off; see issue 18081