espanso/espanso-detect/src/evdev/mod.rs

// This code is a port of the libxkbcommon "interactive-evdev.c" example
// https://github.com/xkbcommon/libxkbcommon/blob/master/tools/interactive-evdev.c

/*
 * This file is part of espanso.
 *
 * Copyright (C) 2019-2021 Federico Terzi
 *
 * espanso 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.
 *
 * espanso 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 espanso.  If not, see <https://www.gnu.org/licenses/>.
 */

mod context;
mod device;
mod ffi;
mod keymap;

use context::Context;
use device::{get_devices, Device};
use keymap::Keymap;
use libc::{
  __errno_location, close, epoll_ctl, epoll_event, epoll_wait, EINTR, EPOLLIN, EPOLL_CTL_ADD,
};
use log::{error, trace};

use crate::event::Status::*;
use crate::event::Variant::*;
use crate::event::{InputEvent, Key, KeyboardEvent, Variant};
use crate::event::{Key::*, MouseButton, MouseEvent};

use self::device::{DeviceError, RawInputEvent};

const BTN_LEFT: u16 = 0x110;
const BTN_RIGHT: u16 = 0x111;
const BTN_MIDDLE: u16 = 0x112;
const BTN_SIDE: u16 = 0x113;
const BTN_EXTRA: u16 = 0x114;

pub type EVDEVSourceCallback = Box<dyn Fn(InputEvent)>;
pub struct EVDEVSource {
  devices: Vec<Device>,
}

#[allow(clippy::new_without_default)]
impl EVDEVSource {
  pub fn new() -> EVDEVSource {
    Self {
      devices: Vec::new(),
    }
  }

  pub fn initialize(&mut self) {
    let context = Context::new().expect("unable to obtain xkb context");
    let keymap = Keymap::new(&context).expect("unable to create xkb keymap");
    match get_devices(&keymap) {
      Ok(devices) => self.devices = devices,
      Err(error) => {
        if let Some(device_error) = error.downcast_ref::<DeviceError>() {
          if matches!(device_error, DeviceError::NoDevicesFound()) {
            error!("Unable to open EVDEV devices, this usually has to do with permissions.");
            error!(
              "You can either add the current user to the 'input' group or run espanso as root"
            );
          }
        }
        panic!("error when initilizing EVDEV source {}", error);
      }
    }
  }

  pub fn eventloop(&self, event_callback: EVDEVSourceCallback) {
    if self.devices.is_empty() {
      panic!("can't start eventloop without evdev devices");
    }

    let raw_epfd = unsafe { libc::epoll_create1(0) };
    let epfd = scopeguard::guard(raw_epfd, |raw_epfd| unsafe {
      close(raw_epfd);
    });

    if *epfd < 0 {
      panic!("could not create epoll instance");
    }

    // Setup epoll for all input devices
    let errno_ptr = unsafe { __errno_location() };
    for (i, device) in self.devices.iter().enumerate() {
      let mut ev: epoll_event = unsafe { std::mem::zeroed() };
      ev.events = EPOLLIN as u32;
      ev.u64 = i as u64;
      if unsafe { epoll_ctl(*epfd, EPOLL_CTL_ADD, device.get_raw_fd(), &mut ev) } != 0 {
        panic!(format!(
          "Could not add {} to epoll, errno {}",
          device.get_path(),
          unsafe { *errno_ptr }
        ));
      }
    }

    // Read events indefinitely
    let mut evs: [epoll_event; 16] = unsafe { std::mem::zeroed() };
    loop {
      let ret = unsafe { epoll_wait(*epfd, evs.as_mut_ptr(), 16, -1) };
      if ret < 0 {
        if unsafe { *errno_ptr } == EINTR {
          continue;
        } else {
          panic!(format!("Could not poll for events, {}", unsafe {
            *errno_ptr
          }))
        }
      }

      for ev in evs.iter() {
        let device = &self.devices[ev.u64 as usize];
        match device.read() {
          Ok(events) if !events.is_empty() => {
            // Convert raw events to the common format and invoke the callback
            events.into_iter().for_each(|raw_event| {
              let event: Option<InputEvent> = raw_event.into();
              if let Some(event) = event {
                event_callback(event);
              } else {
                trace!("unable to convert raw event to input event");
              }
            });
          }
          Ok(_) => { /* SKIP EMPTY */ }
          Err(err) => error!("Can't read from device {}: {}", device.get_path(), err),
        }
      }
    }
  }
}

impl From<RawInputEvent> for Option<InputEvent> {
  fn from(raw: RawInputEvent) -> Option<InputEvent> {
    match raw {
      RawInputEvent::Keyboard(keyboard_event) => {
        let (key, variant) = key_sym_to_key(keyboard_event.sym as i32);
        let value = if keyboard_event.value.is_empty() {
          None
        } else {
          Some(keyboard_event.value)
        };

        let status = if keyboard_event.is_down { Pressed } else { Released };

        return Some(InputEvent::Keyboard(KeyboardEvent {
          key,
          value,
          status,
          variant,
        }));
      }
      RawInputEvent::Mouse(mouse_event) => {
        let button = raw_to_mouse_button(mouse_event.code);

        let status = if mouse_event.is_down { Pressed } else { Released };

        if let Some(button) = button {
          return Some(InputEvent::Mouse(MouseEvent { button, status }));
        }
      }
    }

    None
  }
}

// Mappings from: https://developer.mozilla.org/en-US/docs/Web/API/KeyboardEvent/key/Key_Values
fn key_sym_to_key(key_sym: i32) -> (Key, Option<Variant>) {
  match key_sym {
    // Modifiers
    0xFFE9 => (Alt, Some(Left)),
    0xFFEA => (Alt, Some(Right)),
    0xFFE5 => (CapsLock, None),
    0xFFE3 => (Control, Some(Left)),
    0xFFE4 => (Control, Some(Right)),
    0xFFE7 | 0xFFEB => (Meta, Some(Left)),
    0xFFE8 | 0xFFEC => (Meta, Some(Right)),
    0xFF7F => (NumLock, None),
    0xFFE1 => (Shift, Some(Left)),
    0xFFE2 => (Shift, Some(Right)),

    // Whitespace
    0xFF0D => (Enter, None),
    0xFF09 => (Tab, None),
    0x20 => (Space, None),

    // Navigation
    0xFF54 => (ArrowDown, None),
    0xFF51 => (ArrowLeft, None),
    0xFF53 => (ArrowRight, None),
    0xFF52 => (ArrowUp, None),
    0xFF57 => (End, None),
    0xFF50 => (Home, None),
    0xFF56 => (PageDown, None),
    0xFF55 => (PageUp, None),

    // Editing keys
    0xFF08 => (Backspace, None),

    // Function keys
    0xFFBE => (F1, None),
    0xFFBF => (F2, None),
    0xFFC0 => (F3, None),
    0xFFC1 => (F4, None),
    0xFFC2 => (F5, None),
    0xFFC3 => (F6, None),
    0xFFC4 => (F7, None),
    0xFFC5 => (F8, None),
    0xFFC6 => (F9, None),
    0xFFC7 => (F10, None),
    0xFFC8 => (F11, None),
    0xFFC9 => (F12, None),
    0xFFCA => (F13, None),
    0xFFCB => (F14, None),
    0xFFCC => (F15, None),
    0xFFCD => (F16, None),
    0xFFCE => (F17, None),
    0xFFCF => (F18, None),
    0xFFD0 => (F19, None),
    0xFFD1 => (F20, None),

    // Other keys, includes the raw code provided by the operating system
    _ => (Other(key_sym), None),
  }
}

// These codes can be found in the "input-event-codes.h" header file
fn raw_to_mouse_button(raw: u16) -> Option<MouseButton> {
  match raw {
    BTN_LEFT => Some(MouseButton::Left),
    BTN_RIGHT=> Some(MouseButton::Right),
    BTN_MIDDLE=> Some(MouseButton::Middle),
    BTN_SIDE=> Some(MouseButton::Button1),
    BTN_EXTRA=> Some(MouseButton::Button2),
    _ => None,
  }
}

/* TODO convert tests
#[cfg(test)]
mod tests {
  use std::ffi::CString;

    use super::*;

  fn default_raw_input_event() -> RawInputEvent {
    RawInputEvent {
      event_type: INPUT_EVENT_TYPE_KEYBOARD,
      buffer: [0; 24],
      buffer_len: 0,
      key_code: 0,
      key_sym: 0,
      status: INPUT_STATUS_PRESSED,
    }
  }

  #[test]
  fn raw_to_input_event_keyboard_works_correctly() {
    let c_string = CString::new("k".to_string()).unwrap();
    let mut buffer: [u8; 24] = [0; 24];
    buffer[..1].copy_from_slice(c_string.as_bytes());

    let mut raw = default_raw_input_event();
    raw.buffer = buffer;
    raw.buffer_len = 1;
    raw.status = INPUT_STATUS_RELEASED;
    raw.key_sym = 0x4B;

    let result: Option<InputEvent> = raw.into();
    assert_eq!(
      result.unwrap(),
      InputEvent::Keyboard(KeyboardEvent {
        key: Other(0x4B),
        status: Released,
        value: Some("k".to_string()),
        variant: None,
      })
    );
  }

  #[test]
  fn raw_to_input_event_mouse_works_correctly() {
    let mut raw = default_raw_input_event();
    raw.event_type = INPUT_EVENT_TYPE_MOUSE;
    raw.status = INPUT_STATUS_RELEASED;
    raw.key_code = INPUT_MOUSE_RIGHT_BUTTON;

    let result: Option<InputEvent> = raw.into();
    assert_eq!(
      result.unwrap(),
      InputEvent::Mouse(MouseEvent {
        status: Released,
        button: MouseButton::Right,
      })
    );
  }

  #[test]
  fn raw_to_input_invalid_buffer() {
    let buffer: [u8; 24] = [123; 24];

    let mut raw = default_raw_input_event();
    raw.buffer = buffer;
    raw.buffer_len = 5;

    let result: Option<InputEvent> = raw.into();
    assert!(result.unwrap().into_keyboard().unwrap().value.is_none());
  }

  #[test]
  fn raw_to_input_event_returns_none_when_missing_type() {
    let mut raw = default_raw_input_event();
    raw.event_type = 0;
    let result: Option<InputEvent> = raw.into();
    assert!(result.is_none());
  }
}

*/