esp-idf/tools/idf_monitor_base/console_reader.py

# Copyright 2015-2021 Espressif Systems (Shanghai) CO LTD
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.


import os
import time

from serial.tools.miniterm import Console

from .console_parser import ConsoleParser
from .constants import CMD_STOP, TAG_CMD
from .stoppable_thread import StoppableThread

try:
    import queue
except ImportError:
    import Queue as queue  # type: ignore


class ConsoleReader(StoppableThread):
    """ Read input keys from the console and push them to the queue,
    until stopped.
    """

    def __init__(self, console, event_queue, cmd_queue, parser, test_mode):
        # type: (Console, queue.Queue, queue.Queue, ConsoleParser, bool) -> None
        super(ConsoleReader, self).__init__()
        self.console = console
        self.event_queue = event_queue
        self.cmd_queue = cmd_queue
        self.parser = parser
        self.test_mode = test_mode

    def run(self):
        # type: () -> None
        self.console.setup()
        try:
            while self.alive:
                try:
                    if os.name == 'nt':
                        # Windows kludge: because the console.cancel() method doesn't
                        # seem to work to unblock getkey() on the Windows implementation.
                        #
                        # So we only call getkey() if we know there's a key waiting for us.
                        import msvcrt
                        while not msvcrt.kbhit() and self.alive:  # type: ignore
                            time.sleep(0.1)
                        if not self.alive:
                            break
                    elif self.test_mode:
                        # In testing mode the stdin is connected to PTY but is not used for input anything. For PTY
                        # the canceling by fcntl.ioctl isn't working and would hang in self.console.getkey().
                        # Therefore, we avoid calling it.
                        while self.alive:
                            time.sleep(0.1)
                        break
                    c = self.console.getkey()
                except KeyboardInterrupt:
                    c = '\x03'
                if c is not None:
                    ret = self.parser.parse(c)
                    if ret is not None:
                        (tag, cmd) = ret
                        # stop command should be executed last
                        if tag == TAG_CMD and cmd != CMD_STOP:
                            self.cmd_queue.put(ret)
                        else:
                            self.event_queue.put(ret)

        finally:
            self.console.cleanup()

    def _cancel(self):
        # type: () -> None
        if os.name == 'posix' and not self.test_mode:
            # this is the way cancel() is implemented in pyserial 3.3 or newer,
            # older pyserial (3.1+) has cancellation implemented via 'select',
            # which does not work when console sends an escape sequence response
            #
            # even older pyserial (<3.1) does not have this method
            #
            # on Windows there is a different (also hacky) fix, applied above.
            #
            # note that TIOCSTI is not implemented in WSL / bash-on-Windows.
            # TODO: introduce some workaround to make it work there.
            #
            # Note: This would throw exception in testing mode when the stdin is connected to PTY.
            import fcntl
            import termios
            fcntl.ioctl(self.console.fd, termios.TIOCSTI, b'\0')