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input-remapper/keymapper/injection/injector.py

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#!/usr/bin/python3
# -*- coding: utf-8 -*-
# key-mapper - GUI for device specific keyboard mappings
# Copyright (C) 2021 sezanzeb <proxima@sezanzeb.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/>.
"""Keeps injecting keycodes in the background based on the mapping."""
import asyncio
import time
import multiprocessing
import evdev
from evdev.ecodes import EV_KEY, EV_REL
from keymapper.logger import logger
from keymapper.groups import classify, GAMEPAD, groups
from keymapper import utils
from keymapper.mapping import DISABLE_CODE
from keymapper.injection.keycode_mapper import KeycodeMapper
from keymapper.injection.context import Context
from keymapper.injection.event_producer import EventProducer
from keymapper.injection.numlock import set_numlock, is_numlock_on, \
ensure_numlock
DEV_NAME = 'key-mapper'
# messages
CLOSE = 0
OK = 1
# states
UNKNOWN = -1
STARTING = 2
FAILED = 3
RUNNING = 4
STOPPED = 5
# for both states and messages
NO_GRAB = 6
def is_in_capabilities(key, capabilities):
"""Are this key or one of its sub keys in the capabilities?
Parameters
----------
key : Key
"""
for sub_key in key:
if sub_key[1] in capabilities.get(sub_key[0], []):
return True
return False
class Injector(multiprocessing.Process):
"""Keeps injecting events in the background based on mapping and config.
Is a process to make it non-blocking for the rest of the code and to
make running multiple injector easier. There is one process per
hardware-device that is being mapped.
"""
regrab_timeout = 0.5
def __init__(self, group, mapping):
"""Setup a process to start injecting keycodes based on custom_mapping.
Parameters
----------
group : _Group
the device group
mapping : Mapping
"""
self.group = group
self._event_producer = None
self._state = UNKNOWN
self._msg_pipe = multiprocessing.Pipe()
self.mapping = mapping
self.context = None # only needed inside the injection process
super().__init__()
"""Functions to interact with the running process"""
def get_state(self):
"""Get the state of the injection.
Can be safely called from the main process.
"""
# slowly figure out what is going on
alive = self.is_alive()
if self._state == UNKNOWN and not alive:
# didn't start yet
return self._state
# if it is alive, it is definitely at least starting up
if self._state == UNKNOWN and alive:
self._state = STARTING
# if there is a message available, it might have finished starting up
if self._state == STARTING and self._msg_pipe[1].poll():
msg = self._msg_pipe[1].recv()
if msg == OK:
self._state = RUNNING
if msg == NO_GRAB:
self._state = NO_GRAB
if self._state in [STARTING, RUNNING] and not alive:
self._state = FAILED
logger.error('Injector was unexpectedly found stopped')
return self._state
@ensure_numlock
def stop_injecting(self):
"""Stop injecting keycodes.
Can be safely called from the main procss.
"""
logger.info(
'Stopping injecting keycodes for group "%s"',
self.group.key
)
self._msg_pipe[1].send(CLOSE)
self._state = STOPPED
"""Process internal stuff"""
def _grab_device(self, path):
"""Try to grab the device, return None if not needed/possible."""
try:
device = evdev.InputDevice(path)
except (FileNotFoundError, OSError):
logger.error('Could not find "%s"', path)
return None
capabilities = device.capabilities(absinfo=False)
needed = False
for key, _ in self.context.mapping:
if is_in_capabilities(key, capabilities):
logger.debug('Grabbing "%s" because of "%s"', path, key)
needed = True
break
gamepad = classify(device) == GAMEPAD
if gamepad and self.context.maps_joystick():
logger.debug('Grabbing "%s" because of maps_joystick', path)
needed = True
if not needed:
# skipping reading and checking on events from those devices
# may be beneficial for performance.
logger.debug('No need to grab %s', path)
return None
attempts = 0
while True:
try:
# grab to avoid e.g. the disabled keycode of 10 to confuse
# X, especially when one of the buttons of your mouse also
# uses 10. This also avoids having to load an empty xkb
# symbols file to prevent writing any unwanted keys.
device.grab()
logger.debug('Grab %s', path)
break
except IOError as error:
attempts += 1
# it might take a little time until the device is free if
# it was previously grabbed.
logger.debug('Failed attempts to grab %s: %d', path, attempts)
if attempts >= 4:
logger.error('Cannot grab %s, it is possibly in use', path)
logger.error(str(error))
return None
time.sleep(self.regrab_timeout)
return device
def _copy_capabilities(self, input_device):
"""Copy capabilities for a new device."""
ecodes = evdev.ecodes
# copy the capabilities because the uinput is going
# to act like the device.
capabilities = input_device.capabilities(absinfo=True)
# just like what python-evdev does in from_device
if ecodes.EV_SYN in capabilities:
del capabilities[ecodes.EV_SYN]
if ecodes.EV_FF in capabilities:
del capabilities[ecodes.EV_FF]
if ecodes.ABS_VOLUME in capabilities.get(ecodes.EV_ABS, []):
# For some reason an ABS_VOLUME capability likes to appear
# for some users. It prevents mice from moving around and
# keyboards from writing symbols
capabilities[ecodes.EV_ABS].remove(ecodes.ABS_VOLUME)
return capabilities
def _construct_capabilities(self, gamepad):
"""Adds all used keycodes into a copy of a devices capabilities.
Sometimes capabilities are a bit tricky and change how the system
interprets the device.
Parameters
----------
gamepad : bool
If gamepad events can be translated to mouse events. (also
depends on the configured purpose)
Returns
-------
a mapping of int event type to an array of int event codes.
"""
ecodes = evdev.ecodes
capabilities = {
EV_KEY: []
}
# support all injected keycodes
for code in self.context.key_to_code.values():
if code == DISABLE_CODE:
continue
if code not in capabilities[EV_KEY]:
capabilities[EV_KEY].append(code)
# and all keycodes that are injected by macros
for macro in self.context.macros.values():
macro_capabilities = macro.get_capabilities()
for ev_type in macro_capabilities:
if len(macro_capabilities[ev_type]) == 0:
continue
if ev_type not in capabilities:
capabilities[ev_type] = []
capabilities[ev_type] += list(macro_capabilities[ev_type])
if gamepad and self.context.joystick_as_mouse():
# REL_WHEEL was also required to recognize the gamepad
# as mouse, even if no joystick is used as wheel.
capabilities[EV_REL] = [
evdev.ecodes.REL_X,
evdev.ecodes.REL_Y,
evdev.ecodes.REL_WHEEL,
evdev.ecodes.REL_HWHEEL,
]
if capabilities.get(EV_KEY) is None:
capabilities[EV_KEY] = []
if ecodes.BTN_MOUSE not in capabilities[EV_KEY]:
# to be able to move the cursor, this key capability is
# needed
capabilities[EV_KEY].append(ecodes.BTN_MOUSE)
return capabilities
async def _msg_listener(self):
"""Wait for messages from the main process to do special stuff."""
loop = asyncio.get_event_loop()
while True:
frame_available = asyncio.Event()
loop.add_reader(self._msg_pipe[0].fileno(), frame_available.set)
await frame_available.wait()
frame_available.clear()
msg = self._msg_pipe[0].recv()
if msg == CLOSE:
logger.debug('Received close signal')
# stop the event loop and cause the process to reach its end
# cleanly. Using .terminate prevents coverage from working.
loop.stop()
return
def get_udev_name(self, name, suffix):
"""Make sure the generated name is not longer than 80 chars."""
max_len = 80 # based on error messages
remaining_len = max_len - len(DEV_NAME) - len(suffix) - 2
middle = name[:remaining_len]
name = f'{DEV_NAME} {middle} {suffix}'
return name
def run(self):
"""The injection worker that keeps injecting until terminated.
Stuff is non-blocking by using asyncio in order to do multiple things
somewhat concurrently.
Use this function as starting point in a process. It creates
the loops needed to read and map events and keeps running them.
"""
logger.info('Starting injecting the mapping for "%s"', self.group.key)
# create a new event loop, because somehow running an infinite loop
# that sleeps on iterations (event_producer) in one process causes
# another injection process to screw up reading from the grabbed
# device.
loop = asyncio.new_event_loop()
asyncio.set_event_loop(loop)
# create this within the process after the event loop creation,
# so that the macros use the correct loop
self.context = Context(self.mapping)
self._event_producer = EventProducer(self.context)
numlock_state = is_numlock_on()
coroutines = []
# where mapped events go to.
# See the Context docstring on why this is needed.
self.context.uinput = evdev.UInput(
name=self.get_udev_name(self.group.key, 'mapped'),
phys=DEV_NAME,
events=self._construct_capabilities(GAMEPAD in self.group.types)
)
# Watch over each one of the potentially multiple devices per hardware
for path in self.group.paths:
source = self._grab_device(path)
if source is None:
# this path doesn't need to be grabbed for injection, because
# it doesn't provide the events needed to execute the mapping
continue
# certain capabilities can have side effects apparently. with an
# EV_ABS capability, EV_REL won't move the mouse pointer anymore.
# so don't merge all InputDevices into one UInput device.
gamepad = classify(source) == GAMEPAD
forward_to = evdev.UInput(
name=self.get_udev_name(source.name, 'forwarded'),
phys=DEV_NAME,
events=self._copy_capabilities(source)
)
# actual reading of events
coroutines.append(self._event_consumer(source, forward_to))
# The event source of the current iteration will deliver events
# that are needed for this. It is that one that will be mapped
# to a mouse-like devnode.
if gamepad and self.context.joystick_as_mouse():
self._event_producer.set_abs_range_from(source)
if len(coroutines) == 0:
logger.error('Did not grab any device')
self._msg_pipe[0].send(NO_GRAB)
return
coroutines.append(self._msg_listener())
# run besides this stuff
coroutines.append(self._event_producer.run())
# set the numlock state to what it was before injecting, because
# grabbing devices screws this up
set_numlock(numlock_state)
self._msg_pipe[0].send(OK)
try:
loop.run_until_complete(asyncio.gather(*coroutines))
except RuntimeError:
# stopped event loop most likely
pass
except OSError as error:
logger.error(str(error))
if len(coroutines) > 0:
# expected when stop_injecting is called,
# during normal operation as well as tests this point is not
# reached otherwise.
logger.debug('asyncio coroutines ended')
async def _event_consumer(self, source, forward_to):
"""Reads input events to inject keycodes or talk to the event_producer.
Can be stopped by stopping the asyncio loop. This loop
reads events from a single device only. Other devnodes may be
present for the hardware device, in which case this needs to be
started multiple times.
Parameters
----------
source : evdev.InputDevice
where to read keycodes from
forward_to : evdev.UInput
where to write keycodes to that were not mapped to anything.
Should be an UInput with capabilities that work for all forwarded
events, so ideally they should be copied from source.
"""
logger.debug(
'Started consumer to inject to %s, fd %s',
source.path, source.fd
)
gamepad = classify(source) == GAMEPAD
keycode_handler = KeycodeMapper(self.context, source, forward_to)
async for event in source.async_read_loop():
if self._event_producer.is_handled(event):
# the event_producer will take care of it
self._event_producer.notify(event)
continue
# for mapped stuff
if utils.should_map_as_btn(event, self.context.mapping, gamepad):
will_report_key_up = utils.will_report_key_up(event)
keycode_handler.handle_keycode(event)
if not will_report_key_up:
# simulate a key-up event if no down event arrives anymore.
# this may release macros, combinations or keycodes.
release = evdev.InputEvent(0, 0, event.type, event.code, 0)
self._event_producer.debounce(
debounce_id=(event.type, event.code, event.value),
func=keycode_handler.handle_keycode,
args=(release, False),
ticks=3,
)
continue
# forward the rest
forward_to.write(event.type, event.code, event.value)
# this already includes SYN events, so need to syn here again
# This happens all the time in tests because the async_read_loop
# stops when there is nothing to read anymore. Otherwise tests
# would block.
logger.error('The consumer for "%s" stopped early', source.path)
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