input-remapper/keymapper/linux.py
2020-11-15 03:01:11 +01:00

155 lines
4.9 KiB
Python

#!/usr/bin/python3
# -*- coding: utf-8 -*-
# key-mapper - GUI for device specific keyboard mappings
# Copyright (C) 2020 sezanzeb <proxima@hip70890b.de>
#
# This file is part of key-mapper.
#
# key-mapper 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.
#
# key-mapper 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 key-mapper. If not, see <https://www.gnu.org/licenses/>.
"""Device and evdev stuff that is independent from the display server."""
import subprocess
import evdev
from keymapper.logger import logger
_devices = None
def can_grab(path):
"""Can input events from the device be read?
Parameters
----------
path : string
Path in dev, for example '/dev/input/event7'
"""
p = subprocess.run(['fuser', '-v', path])
return p.returncode == 1
class KeycodeReader:
"""Keeps reading keycodes in the background for the UI to use.
This was written before I figured out there is get_keycode in GLib.
A new arriving keycode indicates that a button was pressed, so the
UI can keep checking for a new keycode on this object and act like the
keycode went right to the input box.
GTK inputs cannot listen on keys that don't write a character, so
they have to repeatedly ask for new data (in this solution).
"""
def __init__(self):
self.virtual_devices = []
def clear(self):
"""Next time when reading don't return the previous keycode."""
# read all of them to clear the buffer or whatever
for virtual_device in self.virtual_devices:
while virtual_device.read_one():
pass
def start_reading(self, device):
"""Tell the evdev lib to start looking for keycodes.
If read is called without prior start_reading, no keycodes
will be available.
"""
paths = _devices[device]['paths']
logger.debug(
'Starting reading keycodes for %s on %s',
device,
', '.join(paths)
)
# Watch over each one of the potentially multiple devices per hardware
self.virtual_devices = [
evdev.InputDevice(path)
for path in paths
]
def read(self):
"""Get the newest key or None if none was pressed."""
newest_keycode = None
for virtual_device in self.virtual_devices:
while True:
event = virtual_device.read_one()
if event is None:
break
if event.type == evdev.ecodes.EV_KEY and event.value == 1:
# value: 1 for down, 0 for up, 2 for hold.
# this happens to report key codes that are 8 lower
# than the ones reported by xev
newest_keycode = event.code + 8
return newest_keycode
keycode_reader = KeycodeReader()
def get_devices():
"""Group devices and get relevant infos per group.
Returns a list containing mappings of
{group_name: {paths: [paths], devices: [names]} for input devices.
For example, group_name could be "Logitech USB Keyboard", devices might
contain "Logitech USB Keyboard System Control" and "Logitech USB Keyboard".
paths is a list of files in /dev/input that belong to the devices.
They are grouped by usb port.
"""
# cache the result, this takes a second to complete
global _devices
if _devices is not None:
return _devices
devices = [evdev.InputDevice(path) for path in evdev.list_devices()]
# group them together by usb device because there could be stuff like
# "Logitech USB Keyboard" and "Logitech USB Keyboard Consumer Control"
grouped = {}
for device in devices:
# only keyboard devices
# https://www.kernel.org/doc/html/latest/input/event-codes.html
if evdev.ecodes.EV_KEY not in device.capabilities().keys():
continue
usb = device.phys.split('/')[0]
if grouped.get(usb) is None:
grouped[usb] = []
grouped[usb].append((device.name, device.path))
# now write down all the paths of that group
result = {}
for group in grouped.values():
names = [entry[0] for entry in group]
devs = [entry[1] for entry in group]
shortest_name = sorted(names, key=len)[0]
result[shortest_name] = {
'paths': devs,
'devices': names
}
_devices = result
logger.info('Found %s', ', '.join([f'"{name}"' for name in result]))
return result