Source code for blessed.keyboard

"""Sub-module providing 'keyboard awareness'."""

# std imports
import re
import time
import platform
from collections import OrderedDict

# 3rd party
import six

# isort: off
# curses
if platform.system() == 'Windows':
    # pylint: disable=import-error
    import jinxed as curses
    from jinxed.has_key import _capability_names as capability_names
    import curses
    from curses.has_key import _capability_names as capability_names

[docs]class Keystroke(six.text_type): """ A unicode-derived class for describing a single keystroke. A class instance describes a single keystroke received on input, which may contain multiple characters as a multibyte sequence, which is indicated by properties :attr:`is_sequence` returning ``True``. When the string is a known sequence, :attr:`code` matches terminal class attributes for comparison, such as ``term.KEY_LEFT``. The string-name of the sequence, such as ``u'KEY_LEFT'`` is accessed by property :attr:`name`, and is used by the :meth:`__repr__` method to display a human-readable form of the Keystroke this class instance represents. It may otherwise by joined, split, or evaluated just as as any other unicode string. """
[docs] def __new__(cls, ucs='', code=None, name=None): """Class constructor.""" new = six.text_type.__new__(cls, ucs) new._name = name new._code = code return new
@property def is_sequence(self): """Whether the value represents a multibyte sequence (bool).""" return self._code is not None def __repr__(self): """Docstring overwritten.""" return (six.text_type.__repr__(self) if self._name is None else self._name) __repr__.__doc__ = six.text_type.__doc__ @property def name(self): """String-name of key sequence, such as ``u'KEY_LEFT'`` (str).""" return self._name @property def code(self): """Integer keycode value of multibyte sequence (int).""" return self._code
def get_curses_keycodes(): """ Return mapping of curses key-names paired by their keycode integer value. :rtype: dict :returns: Dictionary of (name, code) pairs for curses keyboard constant values and their mnemonic name. Such as code ``260``, with the value of its key-name identity, ``u'KEY_LEFT'``. """ _keynames = [attr for attr in dir(curses) if attr.startswith('KEY_')] return {keyname: getattr(curses, keyname) for keyname in _keynames}
[docs]def get_keyboard_codes(): """ Return mapping of keycode integer values paired by their curses key-name. :rtype: dict :returns: Dictionary of (code, name) pairs for curses keyboard constant values and their mnemonic name. Such as key ``260``, with the value of its identity, ``u'KEY_LEFT'``. These keys are derived from the attributes by the same of the curses module, with the following exceptions: * ``KEY_DELETE`` in place of ``KEY_DC`` * ``KEY_INSERT`` in place of ``KEY_IC`` * ``KEY_PGUP`` in place of ``KEY_PPAGE`` * ``KEY_PGDOWN`` in place of ``KEY_NPAGE`` * ``KEY_ESCAPE`` in place of ``KEY_EXIT`` * ``KEY_SUP`` in place of ``KEY_SR`` * ``KEY_SDOWN`` in place of ``KEY_SF`` This function is the inverse of :func:`get_curses_keycodes`. With the given override "mixins" listed above, the keycode for the delete key will map to our imaginary ``KEY_DELETE`` mnemonic, effectively erasing the phrase ``KEY_DC`` from our code vocabulary for anyone that wishes to use the return value to determine the key-name by keycode. """ keycodes = OrderedDict(get_curses_keycodes()) keycodes.update(CURSES_KEYCODE_OVERRIDE_MIXIN) # merge _CURSES_KEYCODE_ADDINS added to our module space keycodes.update( (name, value) for name, value in globals().copy().items() if name.startswith('KEY_') ) # invert dictionary (key, values) => (values, key), preferring the # last-most inserted value ('KEY_DELETE' over 'KEY_DC'). return dict(zip(keycodes.values(), keycodes.keys()))
[docs]def _alternative_left_right(term): r""" Determine and return mapping of left and right arrow keys sequences. :arg blessed.Terminal term: :class:`~.Terminal` instance. :rtype: dict :returns: Dictionary of sequences ``term._cuf1``, and ``term._cub1``, valued as ``KEY_RIGHT``, ``KEY_LEFT`` (when appropriate). This function supports :func:`get_terminal_sequences` to discover the preferred input sequence for the left and right application keys. It is necessary to check the value of these sequences to ensure we do not use ``u' '`` and ``u'\b'`` for ``KEY_RIGHT`` and ``KEY_LEFT``, preferring their true application key sequence, instead. """ # pylint: disable=protected-access keymap = {} if term._cuf1 and term._cuf1 != u' ': keymap[term._cuf1] = curses.KEY_RIGHT if term._cub1 and term._cub1 != u'\b': keymap[term._cub1] = curses.KEY_LEFT return keymap
[docs]def get_keyboard_sequences(term): r""" Return mapping of keyboard sequences paired by keycodes. :arg blessed.Terminal term: :class:`~.Terminal` instance. :returns: mapping of keyboard unicode sequences paired by keycodes as integer. This is used as the argument ``mapper`` to the supporting function :func:`resolve_sequence`. :rtype: OrderedDict Initialize and return a keyboard map and sequence lookup table, (sequence, keycode) from :class:`~.Terminal` instance ``term``, where ``sequence`` is a multibyte input sequence of unicode characters, such as ``u'\x1b[D'``, and ``keycode`` is an integer value, matching curses constant such as term.KEY_LEFT. The return value is an OrderedDict instance, with their keys sorted longest-first. """ # A small gem from curses.has_key that makes this all possible, # _capability_names: a lookup table of terminal capability names for # keyboard sequences (fe. kcub1, key_left), keyed by the values of # constants found beginning with KEY_ in the main curses module # (such as KEY_LEFT). # # latin1 encoding is used so that bytes in 8-bit range of 127-255 # have equivalent chr() and unichr() values, so that the sequence # of a kermit or avatar terminal, for example, remains unchanged # in its byte sequence values even when represented by unicode. # sequence_map = dict(( (seq.decode('latin1'), val) for (seq, val) in ( (curses.tigetstr(cap), val) for (val, cap) in capability_names.items() ) if seq ) if term.does_styling else ()) sequence_map.update(_alternative_left_right(term)) sequence_map.update(DEFAULT_SEQUENCE_MIXIN) # This is for fast lookup matching of sequences, preferring # full-length sequence such as ('\x1b[D', KEY_LEFT) # over simple sequences such as ('\x1b', KEY_EXIT). return OrderedDict(( (seq, sequence_map[seq]) for seq in sorted( sequence_map.keys(), key=len, reverse=True)))
def get_leading_prefixes(sequences): """ Return a set of proper prefixes for given sequence of strings. :arg iterable sequences :rtype: set :return: Set of all string prefixes Given an iterable of strings, all textparts leading up to the final string is returned as a unique set. This function supports the :meth:`~.Terminal.inkey` method by determining whether the given input is a sequence that **may** lead to a final matching pattern. >>> prefixes(['abc', 'abdf', 'e', 'jkl']) set([u'a', u'ab', u'abd', u'j', u'jk']) """ return {seq[:i] for seq in sequences for i in range(1, len(seq))} def resolve_sequence(text, mapper, codes): r""" Return a single :class:`Keystroke` instance for given sequence ``text``. :arg str text: string of characters received from terminal input stream. :arg OrderedDict mapper: unicode multibyte sequences, such as ``u'\x1b[D'`` paired by their integer value (260) :arg dict codes: a :type:`dict` of integer values (such as 260) paired by their mnemonic name, such as ``'KEY_LEFT'``. :rtype: Keystroke :returns: Keystroke instance for the given sequence The given ``text`` may extend beyond a matching sequence, such as ``u\x1b[Dxxx`` returns a :class:`Keystroke` instance of attribute :attr:`Keystroke.sequence` valued only ``u\x1b[D``. It is up to calls to determine that ``xxx`` remains unresolved. """ for sequence, code in mapper.items(): if text.startswith(sequence): return Keystroke(ucs=sequence, code=code, name=codes[code]) return Keystroke(ucs=text and text[0] or u'') def _time_left(stime, timeout): """ Return time remaining since ``stime`` before given ``timeout``. This function assists determining the value of ``timeout`` for class method :meth:`~.Terminal.kbhit` and similar functions. :arg float stime: starting time for measurement :arg float timeout: timeout period, may be set to None to indicate no timeout (where None is always returned). :rtype: float or int :returns: time remaining as float. If no time is remaining, then the integer ``0`` is returned. """ return max(0, timeout - (time.time() - stime)) if timeout else timeout def _read_until(term, pattern, timeout): """ Convenience read-until-pattern function, supporting :meth:`~.get_location`. :arg blessed.Terminal term: :class:`~.Terminal` instance. :arg float timeout: timeout period, may be set to None to indicate no timeout (where 0 is always returned). :arg str pattern: target regular expression pattern to seek. :rtype: tuple :returns: tuple in form of ``(match, str)``, *match* may be :class:`re.MatchObject` if pattern is discovered in input stream before timeout has elapsed, otherwise None. ``str`` is any remaining text received exclusive of the matching pattern). The reason a tuple containing non-matching data is returned, is that the consumer should push such data back into the input buffer by :meth:`~.Terminal.ungetch` if any was received. For example, when a user is performing rapid input keystrokes while its terminal emulator surreptitiously responds to this in-band sequence, we must ensure any such keyboard data is well-received by the next call to term.inkey() without delay. """ stime = time.time() match, buf = None, u'' # first, buffer all pending data. pexpect library provides a # 'searchwindowsize' attribute that limits this memory region. We're not # concerned about OOM conditions: only (human) keyboard input and terminal # response sequences are expected. while True: # pragma: no branch # block as long as necessary to ensure at least one character is # received on input or remaining timeout has elapsed. ucs = term.inkey(timeout=_time_left(stime, timeout)) # while the keyboard buffer is "hot" (has input), we continue to # aggregate all awaiting data. We do this to ensure slow I/O # calls do not unnecessarily give up within the first 'while' loop # for short timeout periods. while ucs: buf += ucs ucs = term.inkey(timeout=0) match =, string=buf) if match is not None: # match break if timeout is not None and not _time_left(stime, timeout): # timeout break return match, buf #: Though we may determine *keynames* and codes for keyboard input that #: generate multibyte sequences, it is also especially useful to aliases #: a few basic ASCII characters such as ``KEY_TAB`` instead of ``u'\t'`` for #: uniformity. #: #: Furthermore, many key-names for application keys enabled only by context #: manager :meth:`~.Terminal.keypad` are surprisingly absent. We inject them #: here directly into the curses module. _CURSES_KEYCODE_ADDINS = ( 'TAB', 'KP_MULTIPLY', 'KP_ADD', 'KP_SEPARATOR', 'KP_SUBTRACT', 'KP_DECIMAL', 'KP_DIVIDE', 'KP_EQUAL', 'KP_0', 'KP_1', 'KP_2', 'KP_3', 'KP_4', 'KP_5', 'KP_6', 'KP_7', 'KP_8', 'KP_9') _LASTVAL = max(get_curses_keycodes().values()) for keycode_name in _CURSES_KEYCODE_ADDINS: _LASTVAL += 1 globals()['KEY_' + keycode_name] = _LASTVAL #: In a perfect world, terminal emulators would always send exactly what #: the terminfo(5) capability database plans for them, accordingly by the #: value of the ``TERM`` name they declare. #: #: But this isn't a perfect world. Many vt220-derived terminals, such as #: those declaring 'xterm', will continue to send vt220 codes instead of #: their native-declared codes, for backwards-compatibility. #: #: This goes for many: rxvt, putty, iTerm. #: #: These "mixins" are used for *all* terminals, regardless of their type. #: #: Furthermore, curses does not provide sequences sent by the keypad, #: at least, it does not provide a way to distinguish between keypad 0 #: and numeric 0. DEFAULT_SEQUENCE_MIXIN = ( # these common control characters (and 127, ctrl+'?') mapped to # an application key definition. (six.unichr(10), curses.KEY_ENTER), (six.unichr(13), curses.KEY_ENTER), (six.unichr(8), curses.KEY_BACKSPACE), (six.unichr(9), KEY_TAB), # noqa # pylint: disable=undefined-variable (six.unichr(27), curses.KEY_EXIT), (six.unichr(127), curses.KEY_BACKSPACE), (u"\x1b[A", curses.KEY_UP), (u"\x1b[B", curses.KEY_DOWN), (u"\x1b[C", curses.KEY_RIGHT), (u"\x1b[D", curses.KEY_LEFT), (u"\x1b[1;2A", curses.KEY_SR), (u"\x1b[1;2B", curses.KEY_SF), (u"\x1b[1;2C", curses.KEY_SRIGHT), (u"\x1b[1;2D", curses.KEY_SLEFT), (u"\x1b[F", curses.KEY_END), (u"\x1b[H", curses.KEY_HOME), # not sure where these are from .. please report (u"\x1b[K", curses.KEY_END), (u"\x1b[U", curses.KEY_NPAGE), (u"\x1b[V", curses.KEY_PPAGE), # keys sent after term.smkx (keypad_xmit) is emitted, source: # # # # keypad, numlock on (u"\x1bOM", curses.KEY_ENTER), # noqa return (u"\x1bOj", KEY_KP_MULTIPLY), # noqa * # pylint: disable=undefined-variable (u"\x1bOk", KEY_KP_ADD), # noqa + # pylint: disable=undefined-variable (u"\x1bOl", KEY_KP_SEPARATOR), # noqa , # pylint: disable=undefined-variable (u"\x1bOm", KEY_KP_SUBTRACT), # noqa - # pylint: disable=undefined-variable (u"\x1bOn", KEY_KP_DECIMAL), # noqa . # pylint: disable=undefined-variable (u"\x1bOo", KEY_KP_DIVIDE), # noqa / # pylint: disable=undefined-variable (u"\x1bOX", KEY_KP_EQUAL), # noqa = # pylint: disable=undefined-variable (u"\x1bOp", KEY_KP_0), # noqa 0 # pylint: disable=undefined-variable (u"\x1bOq", KEY_KP_1), # noqa 1 # pylint: disable=undefined-variable (u"\x1bOr", KEY_KP_2), # noqa 2 # pylint: disable=undefined-variable (u"\x1bOs", KEY_KP_3), # noqa 3 # pylint: disable=undefined-variable (u"\x1bOt", KEY_KP_4), # noqa 4 # pylint: disable=undefined-variable (u"\x1bOu", KEY_KP_5), # noqa 5 # pylint: disable=undefined-variable (u"\x1bOv", KEY_KP_6), # noqa 6 # pylint: disable=undefined-variable (u"\x1bOw", KEY_KP_7), # noqa 7 # pylint: disable=undefined-variable (u"\x1bOx", KEY_KP_8), # noqa 8 # pylint: disable=undefined-variable (u"\x1bOy", KEY_KP_9), # noqa 9 # pylint: disable=undefined-variable # keypad, numlock off (u"\x1b[1~", curses.KEY_FIND), # find (u"\x1b[2~", curses.KEY_IC), # insert (0) (u"\x1b[3~", curses.KEY_DC), # delete (.), "Execute" (u"\x1b[4~", curses.KEY_SELECT), # select (u"\x1b[5~", curses.KEY_PPAGE), # pgup (9) (u"\x1b[6~", curses.KEY_NPAGE), # pgdown (3) (u"\x1b[7~", curses.KEY_HOME), # home (u"\x1b[8~", curses.KEY_END), # end (u"\x1b[OA", curses.KEY_UP), # up (8) (u"\x1b[OB", curses.KEY_DOWN), # down (2) (u"\x1b[OC", curses.KEY_RIGHT), # right (6) (u"\x1b[OD", curses.KEY_LEFT), # left (4) (u"\x1b[OF", curses.KEY_END), # end (1) (u"\x1b[OH", curses.KEY_HOME), # home (7) # The vt220 placed F1-F4 above the keypad, in place of actual # F1-F4 were local functions (hold screen, print screen, # set up, data/talk, break). (u"\x1bOP", curses.KEY_F1), (u"\x1bOQ", curses.KEY_F2), (u"\x1bOR", curses.KEY_F3), (u"\x1bOS", curses.KEY_F4), ) #: Override mixins for a few curses constants with easier #: mnemonics: there may only be a 1:1 mapping when only a #: keycode (int) is given, where these phrases are preferred. CURSES_KEYCODE_OVERRIDE_MIXIN = ( ('KEY_DELETE', curses.KEY_DC), ('KEY_INSERT', curses.KEY_IC), ('KEY_PGUP', curses.KEY_PPAGE), ('KEY_PGDOWN', curses.KEY_NPAGE), ('KEY_ESCAPE', curses.KEY_EXIT), ('KEY_SUP', curses.KEY_SR), ('KEY_SDOWN', curses.KEY_SF), ('KEY_UP_LEFT', curses.KEY_A1), ('KEY_UP_RIGHT', curses.KEY_A3), ('KEY_CENTER', curses.KEY_B2), ('KEY_BEGIN', curses.KEY_BEG), ) __all__ = ('Keystroke', 'get_keyboard_codes', 'get_keyboard_sequences',)