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Diffstat (limited to 'src/prompt_toolkit/input/vt100.py')
| -rw-r--r-- | src/prompt_toolkit/input/vt100.py | 320 |
1 files changed, 320 insertions, 0 deletions
diff --git a/src/prompt_toolkit/input/vt100.py b/src/prompt_toolkit/input/vt100.py new file mode 100644 index 0000000..45ce372 --- /dev/null +++ b/src/prompt_toolkit/input/vt100.py @@ -0,0 +1,320 @@ +import sys + +assert sys.platform != "win32" + +import contextlib +import io +import termios +import tty +from asyncio import AbstractEventLoop +from typing import ( + Callable, + ContextManager, + Dict, + Generator, + List, + Optional, + Set, + TextIO, + Tuple, + Union, +) + +from prompt_toolkit.eventloop import get_event_loop + +from ..key_binding import KeyPress +from .base import Input +from .posix_utils import PosixStdinReader +from .vt100_parser import Vt100Parser + +__all__ = [ + "Vt100Input", + "raw_mode", + "cooked_mode", +] + + +class Vt100Input(Input): + """ + Vt100 input for Posix systems. + (This uses a posix file descriptor that can be registered in the event loop.) + """ + + # For the error messages. Only display "Input is not a terminal" once per + # file descriptor. + _fds_not_a_terminal: Set[int] = set() + + def __init__(self, stdin: TextIO) -> None: + # Test whether the given input object has a file descriptor. + # (Idle reports stdin to be a TTY, but fileno() is not implemented.) + try: + # This should not raise, but can return 0. + stdin.fileno() + except io.UnsupportedOperation as e: + if "idlelib.run" in sys.modules: + raise io.UnsupportedOperation( + "Stdin is not a terminal. Running from Idle is not supported." + ) from e + else: + raise io.UnsupportedOperation("Stdin is not a terminal.") from e + + # Even when we have a file descriptor, it doesn't mean it's a TTY. + # Normally, this requires a real TTY device, but people instantiate + # this class often during unit tests as well. They use for instance + # pexpect to pipe data into an application. For convenience, we print + # an error message and go on. + isatty = stdin.isatty() + fd = stdin.fileno() + + if not isatty and fd not in Vt100Input._fds_not_a_terminal: + msg = "Warning: Input is not a terminal (fd=%r).\n" + sys.stderr.write(msg % fd) + sys.stderr.flush() + Vt100Input._fds_not_a_terminal.add(fd) + + # + self.stdin = stdin + + # Create a backup of the fileno(). We want this to work even if the + # underlying file is closed, so that `typeahead_hash()` keeps working. + self._fileno = stdin.fileno() + + self._buffer: List[KeyPress] = [] # Buffer to collect the Key objects. + self.stdin_reader = PosixStdinReader(self._fileno, encoding=stdin.encoding) + self.vt100_parser = Vt100Parser( + lambda key_press: self._buffer.append(key_press) + ) + + def attach(self, input_ready_callback: Callable[[], None]) -> ContextManager[None]: + """ + Return a context manager that makes this input active in the current + event loop. + """ + return _attached_input(self, input_ready_callback) + + def detach(self) -> ContextManager[None]: + """ + Return a context manager that makes sure that this input is not active + in the current event loop. + """ + return _detached_input(self) + + def read_keys(self) -> List[KeyPress]: + "Read list of KeyPress." + # Read text from stdin. + data = self.stdin_reader.read() + + # Pass it through our vt100 parser. + self.vt100_parser.feed(data) + + # Return result. + result = self._buffer + self._buffer = [] + return result + + def flush_keys(self) -> List[KeyPress]: + """ + Flush pending keys and return them. + (Used for flushing the 'escape' key.) + """ + # Flush all pending keys. (This is most important to flush the vt100 + # 'Escape' key early when nothing else follows.) + self.vt100_parser.flush() + + # Return result. + result = self._buffer + self._buffer = [] + return result + + @property + def closed(self) -> bool: + return self.stdin_reader.closed + + def raw_mode(self) -> ContextManager[None]: + return raw_mode(self.stdin.fileno()) + + def cooked_mode(self) -> ContextManager[None]: + return cooked_mode(self.stdin.fileno()) + + def fileno(self) -> int: + return self.stdin.fileno() + + def typeahead_hash(self) -> str: + return f"fd-{self._fileno}" + + +_current_callbacks: Dict[ + Tuple[AbstractEventLoop, int], Optional[Callable[[], None]] +] = {} # (loop, fd) -> current callback + + +@contextlib.contextmanager +def _attached_input( + input: Vt100Input, callback: Callable[[], None] +) -> Generator[None, None, None]: + """ + Context manager that makes this input active in the current event loop. + + :param input: :class:`~prompt_toolkit.input.Input` object. + :param callback: Called when the input is ready to read. + """ + loop = get_event_loop() + fd = input.fileno() + previous = _current_callbacks.get((loop, fd)) + + def callback_wrapper() -> None: + """Wrapper around the callback that already removes the reader when + the input is closed. Otherwise, we keep continuously calling this + callback, until we leave the context manager (which can happen a bit + later). This fixes issues when piping /dev/null into a prompt_toolkit + application.""" + if input.closed: + loop.remove_reader(fd) + callback() + + try: + loop.add_reader(fd, callback_wrapper) + except PermissionError: + # For `EPollSelector`, adding /dev/null to the event loop will raise + # `PermisisonError` (that doesn't happen for `SelectSelector` + # apparently). Whenever we get a `PermissionError`, we can raise + # `EOFError`, because there's not more to be read anyway. `EOFError` is + # an exception that people expect in + # `prompt_toolkit.application.Application.run()`. + # To reproduce, do: `ptpython 0< /dev/null 1< /dev/null` + raise EOFError + + _current_callbacks[loop, fd] = callback + + try: + yield + finally: + loop.remove_reader(fd) + + if previous: + loop.add_reader(fd, previous) + _current_callbacks[loop, fd] = previous + else: + del _current_callbacks[loop, fd] + + +@contextlib.contextmanager +def _detached_input(input: Vt100Input) -> Generator[None, None, None]: + loop = get_event_loop() + fd = input.fileno() + previous = _current_callbacks.get((loop, fd)) + + if previous: + loop.remove_reader(fd) + _current_callbacks[loop, fd] = None + + try: + yield + finally: + if previous: + loop.add_reader(fd, previous) + _current_callbacks[loop, fd] = previous + + +class raw_mode: + """ + :: + + with raw_mode(stdin): + ''' the pseudo-terminal stdin is now used in raw mode ''' + + We ignore errors when executing `tcgetattr` fails. + """ + + # There are several reasons for ignoring errors: + # 1. To avoid the "Inappropriate ioctl for device" crash if somebody would + # execute this code (In a Python REPL, for instance): + # + # import os; f = open(os.devnull); os.dup2(f.fileno(), 0) + # + # The result is that the eventloop will stop correctly, because it has + # to logic to quit when stdin is closed. However, we should not fail at + # this point. See: + # https://github.com/jonathanslenders/python-prompt-toolkit/pull/393 + # https://github.com/jonathanslenders/python-prompt-toolkit/issues/392 + + # 2. Related, when stdin is an SSH pipe, and no full terminal was allocated. + # See: https://github.com/jonathanslenders/python-prompt-toolkit/pull/165 + def __init__(self, fileno: int) -> None: + self.fileno = fileno + self.attrs_before: Optional[List[Union[int, List[Union[bytes, int]]]]] + try: + self.attrs_before = termios.tcgetattr(fileno) + except termios.error: + # Ignore attribute errors. + self.attrs_before = None + + def __enter__(self) -> None: + # NOTE: On os X systems, using pty.setraw() fails. Therefor we are using this: + try: + newattr = termios.tcgetattr(self.fileno) + except termios.error: + pass + else: + newattr[tty.LFLAG] = self._patch_lflag(newattr[tty.LFLAG]) + newattr[tty.IFLAG] = self._patch_iflag(newattr[tty.IFLAG]) + + # VMIN defines the number of characters read at a time in + # non-canonical mode. It seems to default to 1 on Linux, but on + # Solaris and derived operating systems it defaults to 4. (This is + # because the VMIN slot is the same as the VEOF slot, which + # defaults to ASCII EOT = Ctrl-D = 4.) + newattr[tty.CC][termios.VMIN] = 1 + + termios.tcsetattr(self.fileno, termios.TCSANOW, newattr) + + @classmethod + def _patch_lflag(cls, attrs: int) -> int: + return attrs & ~(termios.ECHO | termios.ICANON | termios.IEXTEN | termios.ISIG) + + @classmethod + def _patch_iflag(cls, attrs: int) -> int: + return attrs & ~( + # Disable XON/XOFF flow control on output and input. + # (Don't capture Ctrl-S and Ctrl-Q.) + # Like executing: "stty -ixon." + termios.IXON + | termios.IXOFF + | + # Don't translate carriage return into newline on input. + termios.ICRNL + | termios.INLCR + | termios.IGNCR + ) + + def __exit__(self, *a: object) -> None: + if self.attrs_before is not None: + try: + termios.tcsetattr(self.fileno, termios.TCSANOW, self.attrs_before) + except termios.error: + pass + + # # Put the terminal in application mode. + # self._stdout.write('\x1b[?1h') + + +class cooked_mode(raw_mode): + """ + The opposite of ``raw_mode``, used when we need cooked mode inside a + `raw_mode` block. Used in `Application.run_in_terminal`.:: + + with cooked_mode(stdin): + ''' the pseudo-terminal stdin is now used in cooked mode. ''' + """ + + @classmethod + def _patch_lflag(cls, attrs: int) -> int: + return attrs | (termios.ECHO | termios.ICANON | termios.IEXTEN | termios.ISIG) + + @classmethod + def _patch_iflag(cls, attrs: int) -> int: + # Turn the ICRNL flag back on. (Without this, calling `input()` in + # run_in_terminal doesn't work and displays ^M instead. Ptpython + # evaluates commands using `run_in_terminal`, so it's important that + # they translate ^M back into ^J.) + return attrs | termios.ICRNL |