input.py

# -*- coding: utf-8 -*-
#
#    Copyright (C) 2015 Rodrigo Silva (MestreLion) <linux@rodrigosilva.com>
#
#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation, either version 3 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program. See <http://www.gnu.org/licenses/gpl.html>

'''
Abstraction layer to deal with terminal keyboard input
and related curses methods and constants
'''

import os
import sys
import curses.ascii
import locale

# enum from stdlib doesn't allow re-assignments, so we use our custom one
from . import enum2 as enum


if sys.version < '3':
    def b2s(b):
        return b
else:
    def b2s(b):
        return str(b, encoding=locale.getpreferredencoding())


class MOVE(enum.Enum):
    UP         = (curses.KEY_UP,    ord('k'))
    DOWN       = (curses.KEY_DOWN,  ord('j'))
    LEFT       = (curses.KEY_LEFT,  ord('h'))
    RIGHT      = (curses.KEY_RIGHT, ord('l'))
    UP_RIGHT   = (curses.KEY_PPAGE, ord('u'), curses.KEY_A3)
    DOWN_RIGHT = (curses.KEY_NPAGE, ord('n'), curses.KEY_C3)
    UP_LEFT    = (curses.KEY_HOME,  ord('y'), curses.KEY_A1, curses.KEY_FIND)
    DOWN_LEFT  = (curses.KEY_END,   ord('b'), curses.KEY_C1, curses.KEY_SELECT)


class KEY(enum.Enum):
    RESIZE = curses.KEY_RESIZE
    F1  = curses.KEY_F1
    F2  = curses.KEY_F2
    F3  = curses.KEY_F3
    F4  = curses.KEY_F4
    F5  = curses.KEY_F5
    F6  = curses.KEY_F6
    F7  = curses.KEY_F7
    F8  = curses.KEY_F8
    F9  = curses.KEY_F9
    F10 = curses.KEY_F10
    F11 = curses.KEY_F11
    F12 = curses.KEY_F12

    # Some aliases
    INSERT = curses.KEY_IC
    DELETE = curses.KEY_DC
    NUM_5  = curses.KEY_B2
    ALT_F9 = curses.KEY_F57
    ESC    = curses.ascii.ESC


# The above make static analyzers like Pylint and Pydev happy
# Now generate all other KEY constants
for __ in dir(curses):
    if __.startswith("KEY_"):
        setattr(KEY, __[4:], getattr(curses, __))


def ctrl(c):
    return curses.ascii.ctrl(ord(c))


def getch(window):
    '''Get a character from user. Blocks until input.
        Wrapper for curses.window.getch()
    '''
    return window.window.getch()


def unctrl(ch):
    '''Return a a printable representation of character ch.
        Control characters are displayed with a caret, for example ^C.
        Printing characters are left as they are.
        Wrapper for curses.unctrl()
    '''
    return b2s(curses.unctrl(ch))


if os.environ.get('DISPLAY') is None:

    is_console = True

    def keyboard_leds():
        import struct
        import fcntl

        DEVICE = '/dev/tty'
        KDGETLED = 0x4B31
        SCRLOCK = 0x01
        NUMLOCK = 0x02
        CAPLOCK = 0x04

        leds = 0
        try:
            fd = os.open(DEVICE, os.O_RDONLY | os.O_NOCTTY)
            retbytes = fcntl.ioctl(fd, KDGETLED, struct.pack('I', 0))
            [leds] = struct.unpack('I', retbytes)
        except IOError:  # not a true tty console, but an X11 terminal emulator
            pass

        return (("NUM LOCK", bool(leds & NUMLOCK)),
                ("CAP LOCK", bool(leds & CAPLOCK)),
                ("SCR LOCK", bool(leds & SCRLOCK)))


else:

    is_console = False

    def keyboard_leds():
        import subprocess

        SCRLOCK = 0x04
        NUMLOCK = 0x02
        CAPLOCK = 0x01

        leds = 0
        try:
            for line in (subprocess.check_output(["xset", "-q"]).
                         decode(locale.getpreferredencoding()).
                         split('\n')):
                if 'LED mask' in line:
                    leds = int(line.split(' ')[-1])
                    break
        except subprocess.CalledProcessError:
            pass

        return (("NUM LOCK", bool(leds & NUMLOCK)),
                ("CAP LOCK", bool(leds & CAPLOCK)),
                ("SCR LOCK", bool(leds & SCRLOCK)))