cpython/Lib/idlelib/run.py

import sys
import linecache
import time
import traceback
import _thread as thread
import threading
import queue
import tkinter

from idlelib import CallTips
from idlelib import AutoComplete

from idlelib import RemoteDebugger
from idlelib import RemoteObjectBrowser
from idlelib import StackViewer
from idlelib import rpc
from idlelib import PyShell
from idlelib import IOBinding

import __main__

LOCALHOST = '127.0.0.1'

import warnings

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

    The only difference is the formatter called.
    """
    if file is None:
        file = sys.stderr
    try:
        file.write(PyShell.idle_formatwarning(
                message, category, filename, lineno, line))
    except IOError:
        pass # the file (probably stderr) is invalid - this warning gets lost.

_warnings_showwarning = None

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

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

capture_warnings(True)
tcl = tkinter.Tcl()

def handle_tk_events(tcl=tcl):
    """Process any tk events that are ready to be dispatched if tkinter
    has been imported, a tcl interpreter has been created and tk has been
    loaded."""
    tcl.eval("update")

# Thread shared globals: Establish a queue between a subthread (which handles
# the socket) and the main thread (which runs user code), plus global
# completion, exit and interruptable (the main thread) flags:

exit_now = False
quitting = False
interruptable = False

def main(del_exitfunc=False):
    """Start the Python execution server in a subprocess

    In the Python subprocess, RPCServer is instantiated with handlerclass
    MyHandler, which inherits register/unregister methods from RPCHandler via
    the mix-in class SocketIO.

    When the RPCServer 'server' is instantiated, the TCPServer initialization
    creates an instance of run.MyHandler and calls its handle() method.
    handle() instantiates a run.Executive object, passing it a reference to the
    MyHandler object.  That reference is saved as attribute rpchandler of the
    Executive instance.  The Executive methods have access to the reference and
    can pass it on to entities that they command
    (e.g. RemoteDebugger.Debugger.start_debugger()).  The latter, in turn, can
    call MyHandler(SocketIO) register/unregister methods via the reference to
    register and unregister themselves.

    """
    global exit_now
    global quitting
    global no_exitfunc
    no_exitfunc = del_exitfunc
    #time.sleep(15) # test subprocess not responding
    try:
        assert(len(sys.argv) > 1)
        port = int(sys.argv[-1])
    except:
        print("IDLE Subprocess: no IP port passed in sys.argv.",
              file=sys.__stderr__)
        return

    capture_warnings(True)
    sys.argv[:] = [""]
    sockthread = threading.Thread(target=manage_socket,
                                  name='SockThread',
                                  args=((LOCALHOST, port),))
    sockthread.daemon = True
    sockthread.start()
    while 1:
        try:
            if exit_now:
                try:
                    exit()
                except KeyboardInterrupt:
                    # exiting but got an extra KBI? Try again!
                    continue
            try:
                seq, request = rpc.request_queue.get(block=True, timeout=0.05)
            except queue.Empty:
                handle_tk_events()
                continue
            method, args, kwargs = request
            ret = method(*args, **kwargs)
            rpc.response_queue.put((seq, ret))
        except KeyboardInterrupt:
            if quitting:
                exit_now = True
            continue
        except SystemExit:
            capture_warnings(False)
            raise
        except:
            type, value, tb = sys.exc_info()
            try:
                print_exception()
                rpc.response_queue.put((seq, None))
            except:
                # Link didn't work, print same exception to __stderr__
                traceback.print_exception(type, value, tb, file=sys.__stderr__)
                exit()
            else:
                continue

def manage_socket(address):
    for i in range(3):
        time.sleep(i)
        try:
            server = MyRPCServer(address, MyHandler)
            break
        except OSError as err:
            print("IDLE Subprocess: OSError: " + err.args[1] +
                  ", retrying....", file=sys.__stderr__)
            socket_error = err
    else:
        print("IDLE Subprocess: Connection to "
              "IDLE GUI failed, exiting.", file=sys.__stderr__)
        show_socket_error(socket_error, address)
        global exit_now
        exit_now = True
        return
    server.handle_request() # A single request only

def show_socket_error(err, address):
    import tkinter
    import tkinter.messagebox as tkMessageBox
    root = tkinter.Tk()
    root.withdraw()
    if err.args[0] == 61: # connection refused
        msg = "IDLE's subprocess can't connect to %s:%d.  This may be due "\
              "to your personal firewall configuration.  It is safe to "\
              "allow this internal connection because no data is visible on "\
              "external ports." % address
        tkMessageBox.showerror("IDLE Subprocess Error", msg, parent=root)
    else:
        tkMessageBox.showerror("IDLE Subprocess Error",
                               "Socket Error: %s" % err.args[1])
    root.destroy()

def print_exception():
    import linecache
    linecache.checkcache()
    flush_stdout()
    efile = sys.stderr
    typ, val, tb = excinfo = sys.exc_info()
    sys.last_type, sys.last_value, sys.last_traceback = excinfo
    seen = set()

    def print_exc(typ, exc, tb):
        seen.add(exc)
        context = exc.__context__
        cause = exc.__cause__
        if cause is not None and cause not in seen:
            print_exc(type(cause), cause, cause.__traceback__)
            print("\nThe above exception was the direct cause "
                  "of the following exception:\n", file=efile)
        elif (context is not None and
              not exc.__suppress_context__ and
              context not in seen):
            print_exc(type(context), context, context.__traceback__)
            print("\nDuring handling of the above exception, "
                  "another exception occurred:\n", file=efile)
        if tb:
            tbe = traceback.extract_tb(tb)
            print('Traceback (most recent call last):', file=efile)
            exclude = ("run.py", "rpc.py", "threading.py", "queue.py",
                       "RemoteDebugger.py", "bdb.py")
            cleanup_traceback(tbe, exclude)
            traceback.print_list(tbe, file=efile)
        lines = traceback.format_exception_only(typ, exc)
        for line in lines:
            print(line, end='', file=efile)

    print_exc(typ, val, tb)

def cleanup_traceback(tb, exclude):
    "Remove excluded traces from beginning/end of tb; get cached lines"
    orig_tb = tb[:]
    while tb:
        for rpcfile in exclude:
            if tb[0][0].count(rpcfile):
                break    # found an exclude, break for: and delete tb[0]
        else:
            break        # no excludes, have left RPC code, break while:
        del tb[0]
    while tb:
        for rpcfile in exclude:
            if tb[-1][0].count(rpcfile):
                break
        else:
            break
        del tb[-1]
    if len(tb) == 0:
        # exception was in IDLE internals, don't prune!
        tb[:] = orig_tb[:]
        print("** IDLE Internal Exception: ", file=sys.stderr)
    rpchandler = rpc.objecttable['exec'].rpchandler
    for i in range(len(tb)):
        fn, ln, nm, line = tb[i]
        if nm == '?':
            nm = "-toplevel-"
        if not line and fn.startswith("<pyshell#"):
            line = rpchandler.remotecall('linecache', 'getline',
                                              (fn, ln), {})
        tb[i] = fn, ln, nm, line

def flush_stdout():
    """XXX How to do this now?"""

def exit():
    """Exit subprocess, possibly after first clearing exit functions.

    If config-main.cfg/.def 'General' 'delete-exitfunc' is True, then any
    functions registered with atexit will be removed before exiting.
    (VPython support)

    """
    if no_exitfunc:
        import atexit
        atexit._clear()
    capture_warnings(False)
    sys.exit(0)

class MyRPCServer(rpc.RPCServer):

    def handle_error(self, request, client_address):
        """Override RPCServer method for IDLE

        Interrupt the MainThread and exit server if link is dropped.

        """
        global quitting
        try:
            raise
        except SystemExit:
            raise
        except EOFError:
            global exit_now
            exit_now = True
            thread.interrupt_main()
        except:
            erf = sys.__stderr__
            print('\n' + '-'*40, file=erf)
            print('Unhandled server exception!', file=erf)
            print('Thread: %s' % threading.current_thread().name, file=erf)
            print('Client Address: ', client_address, file=erf)
            print('Request: ', repr(request), file=erf)
            traceback.print_exc(file=erf)
            print('\n*** Unrecoverable, server exiting!', file=erf)
            print('-'*40, file=erf)
            quitting = True
            thread.interrupt_main()

class MyHandler(rpc.RPCHandler):

    def handle(self):
        """Override base method"""
        executive = Executive(self)
        self.register("exec", executive)
        self.console = self.get_remote_proxy("console")
        sys.stdin = PyShell.PseudoInputFile(self.console, "stdin",
                IOBinding.encoding)
        sys.stdout = PyShell.PseudoOutputFile(self.console, "stdout",
                IOBinding.encoding)
        sys.stderr = PyShell.PseudoOutputFile(self.console, "stderr",
                IOBinding.encoding)

        sys.displayhook = rpc.displayhook
        # page help() text to shell.
        import pydoc # import must be done here to capture i/o binding
        pydoc.pager = pydoc.plainpager

        # Keep a reference to stdin so that it won't try to exit IDLE if
        # sys.stdin gets changed from within IDLE's shell. See issue17838.
        self._keep_stdin = sys.stdin

        self.interp = self.get_remote_proxy("interp")
        rpc.RPCHandler.getresponse(self, myseq=None, wait=0.05)

    def exithook(self):
        "override SocketIO method - wait for MainThread to shut us down"
        time.sleep(10)

    def EOFhook(self):
        "Override SocketIO method - terminate wait on callback and exit thread"
        global quitting
        quitting = True
        thread.interrupt_main()

    def decode_interrupthook(self):
        "interrupt awakened thread"
        global quitting
        quitting = True
        thread.interrupt_main()


class Executive(object):

    def __init__(self, rpchandler):
        self.rpchandler = rpchandler
        self.locals = __main__.__dict__
        self.calltip = CallTips.CallTips()
        self.autocomplete = AutoComplete.AutoComplete()

    def runcode(self, code):
        global interruptable
        try:
            self.usr_exc_info = None
            interruptable = True
            try:
                exec(code, self.locals)
            finally:
                interruptable = False
        except SystemExit:
            # Scripts that raise SystemExit should just
            # return to the interactive prompt
            pass
        except:
            self.usr_exc_info = sys.exc_info()
            if quitting:
                exit()
            # even print a user code SystemExit exception, continue
            print_exception()
            jit = self.rpchandler.console.getvar("<<toggle-jit-stack-viewer>>")
            if jit:
                self.rpchandler.interp.open_remote_stack_viewer()
        else:
            flush_stdout()

    def interrupt_the_server(self):
        if interruptable:
            thread.interrupt_main()

    def start_the_debugger(self, gui_adap_oid):
        return RemoteDebugger.start_debugger(self.rpchandler, gui_adap_oid)

    def stop_the_debugger(self, idb_adap_oid):
        "Unregister the Idb Adapter.  Link objects and Idb then subject to GC"
        self.rpchandler.unregister(idb_adap_oid)

    def get_the_calltip(self, name):
        return self.calltip.fetch_tip(name)

    def get_the_completion_list(self, what, mode):
        return self.autocomplete.fetch_completions(what, mode)

    def stackviewer(self, flist_oid=None):
        if self.usr_exc_info:
            typ, val, tb = self.usr_exc_info
        else:
            return None
        flist = None
        if flist_oid is not None:
            flist = self.rpchandler.get_remote_proxy(flist_oid)
        while tb and tb.tb_frame.f_globals["__name__"] in ["rpc", "run"]:
            tb = tb.tb_next
        sys.last_type = typ
        sys.last_value = val
        item = StackViewer.StackTreeItem(flist, tb)
        return RemoteObjectBrowser.remote_object_tree_item(item)

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