xcrab/src/main.rs

// Copyright (C) 2022 Infoshock Tech

// 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.  If not, see <http://www.gnu.org/licenses/>.

#![warn(clippy::pedantic)]

use std::fmt::{Debug, Display};

use breadx::{
    auto::xproto::{GrabKeyRequest, GrabMode, KeyButMask, Keycode, Keysym, ModMask},
    keyboard::KeyboardState,
    prelude::{AsyncDisplay, AsyncDisplayXprotoExt, MapState},
    traits::DisplayBase,
    AsyncDisplayConnection, AsyncDisplayExt, BreadError, ConfigureWindowParameters, Event,
    EventMask, Window,
};

use lazy_static::lazy_static;

use tokio::sync::mpsc::unbounded_channel;

mod config;
mod msg_listener;
mod x11;

use x11::client::{may_not_exist, XcrabWindowManager};

use std::collections::HashMap;

#[non_exhaustive]
pub enum XcrabError {
    Bread(BreadError),
    Io(std::io::Error),
    Toml(toml::de::Error),
    Var(std::env::VarError),
    ClientDoesntExist,
    Custom(String),
}

impl From<BreadError> for XcrabError {
    fn from(v: BreadError) -> Self {
        Self::Bread(v)
    }
}

impl From<std::io::Error> for XcrabError {
    fn from(v: std::io::Error) -> Self {
        Self::Io(v)
    }
}

impl From<toml::de::Error> for XcrabError {
    fn from(v: toml::de::Error) -> Self {
        Self::Toml(v)
    }
}

impl From<std::env::VarError> for XcrabError {
    fn from(v: std::env::VarError) -> Self {
        Self::Var(v)
    }
}

impl From<String> for XcrabError {
    fn from(v: String) -> Self {
        Self::Custom(v)
    }
}

lazy_static! {
    pub static ref CONFIG: config::XcrabConfig = config::load_file().unwrap_or_else(|e| {
        println!("[CONFIG] Error parsing config: {e}");
        println!("[CONFIG] Falling back to default config");
        config::XcrabConfig::default()
    });
}

impl Display for XcrabError {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::Bread(be) => Display::fmt(&be, f)?,
            Self::Io(ie) => Display::fmt(&ie, f)?,
            Self::Toml(te) => Display::fmt(&te, f)?,
            Self::Var(ve) => Display::fmt(&ve, f)?,
            Self::ClientDoesntExist => Display::fmt("client didn't exist", f)?,
            Self::Custom(fe) => Display::fmt(fe, f)?,
        };

        Ok(())
    }
}

impl Debug for XcrabError {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        Display::fmt(self, f)
    }
}

type Result<T> = std::result::Result<T, XcrabError>;

#[tokio::main]
async fn main() -> Result<()> {
    // connect to the x server
    let mut conn = AsyncDisplayConnection::create_async(None, None).await?;

    let root = conn.default_root();

    // listen for substructure redirects to intercept events like window creation
    root.set_event_mask_async(
        &mut conn,
        EventMask::SUBSTRUCTURE_REDIRECT | EventMask::SUBSTRUCTURE_NOTIFY | EventMask::KEY_PRESS,
    )
    .await?;

    let mut manager = XcrabWindowManager::new();

    conn.grab_server_async().await?;

    let top_level_windows = root.query_tree_immediate_async(&mut conn).await?.children;

    for &win in top_level_windows.iter() {
        let attrs = win.window_attributes_immediate_async(&mut conn).await?;

        if !attrs.override_redirect && attrs.map_state == MapState::Viewable {
            manager.add_client(&mut conn, win).await?;
        }
    }

    conn.ungrab_server_async().await?;

    let mut mask = ModMask::new(false, false, true, false, false, false, false, false, false);
    let mut keyboard_state = KeyboardState::new_async(&mut conn).await?;
    let keymap = keymap(&mut keyboard_state);
    let mut request_key = *keymap.get(&120).ok_or_else(|| {
        XcrabError::Custom("At least one letter could not be found in the keymap".to_string())
    })?;

    for &binds in CONFIG.binds.keys() {
        for keysym in 97..122_u32 {
            let keycode = keymap.get(&keysym).ok_or_else(|| {
                XcrabError::Custom(
                    "At least one letter could not be found in the keymap".to_string(),
                )
            })?;
            let iter_char = keyboard_state
                .process_keycode(*keycode, KeyButMask::default())
                .ok_or_else(|| {
                    XcrabError::Custom(
                        "The keycode returned from the keymap could not be processed".to_string(),
                    )
                })?
                .as_char()
                .ok_or_else(|| {
                    XcrabError::Custom("The processed Key could not be cast as a char".to_string())
                })?;
            if iter_char == binds.key {
                request_key = *keycode;
                mask.inner = binds.mods.inner;
            }
        }
    }

    mask.set_Two(true);

    conn.exchange_request_async(GrabKeyRequest {
        req_type: 33,
        owner_events: false,
        length: 4,
        grab_window: root,
        modifiers: mask,
        key: request_key,
        pointer_mode: GrabMode::Async,
        keyboard_mode: GrabMode::Async,
    })
    .await?;

    let (send, mut recv) = unbounded_channel();
    let (result_send, result_recv) = unbounded_channel();

    tokio::spawn(msg_listener::listener_task(
        CONFIG.msg.clone().unwrap_or_default().socket_path,
        send,
        result_recv,
    ));

    loop {
        // biased mode makes select! poll the channel first in order to keep xcrab-msg from being
        // starved by x11 events. Probably unnecessary, but better safe than sorry.
        tokio::select! {
            biased;
            Some(s) = recv.recv() => msg_listener::on_recv(s, &mut manager, &mut conn, &result_send).await?,
            Ok(ev) = conn.wait_for_event_async() => process_event(ev, &mut manager, &mut conn, root, &mut keyboard_state).await?,
        }
    }
}

async fn process_event<Dpy: AsyncDisplay + ?Sized>(
    ev: Event,
    manager: &mut XcrabWindowManager,
    conn: &mut Dpy,
    root: Window,
    keyboard_state: &mut KeyboardState,
) -> Result<()> {
    match ev {
        Event::MapRequest(ev) => {
            manager.add_client(conn, ev.window).await?;
        }
        Event::ConfigureRequest(ev) => {
            // copy from `ev` to `params`
            let mut params = ConfigureWindowParameters {
                x: Some(ev.x.into()),
                y: Some(ev.y.into()),
                width: Some(ev.width.into()),
                height: Some(ev.height.into()),
                border_width: Some(ev.border_width.into()),
                // without this, it will error when a window tries to set a sibling that is
                // not actually a sibling? idk, all i know is that without it, xterm crashes
                sibling: None,
                stack_mode: Some(ev.stack_mode),
            };

            // if this is a client, deny changing position or size (we are a tiling wm!)
            if manager.has_client(ev.window) {
                params.x = None;
                params.y = None;
                params.width = None;
                params.height = None;
            }

            // forward the request
            // by the time we get here someone may have already deleted their window
            may_not_exist(ev.window.configure_async(conn, params).await)?;
        }
        Event::UnmapNotify(ev) => {
            if ev.event != root && manager.has_client(ev.window) {
                manager.remove_client(conn, ev.window).await?;
            }
        }
        Event::ButtonPress(ev) => {
            if ev.detail == 1 {
                manager.set_focus(conn, ev.event).await?;
            }
        }
        Event::KeyPress(ev) => {
            if let Some(k) = keyboard_state.process_keycode(ev.detail, ev.state) {
                if let Some(c) = k.as_char() {
                    for (&bind, action) in &CONFIG.binds {
                        if bind.key == c {
                            action.eval(manager, conn).await?;
                        }
                    }
                }
            }
        }
        _ => {}
    }
    Ok(())
}

// I will move this to x11/client.rs eventually
// this is just ease of coding for now

fn keymap(state: &mut KeyboardState) -> HashMap<Keysym, Keycode> {
    let mut map: HashMap<Keysym, Keycode> = HashMap::new();
    for keycode in 8..255_u8 {
        let key = state.process_keycode(keycode, KeyButMask::default());
        let keysyms = state.lookup_keysyms(keycode);
        if key != None {
            for keysym in keysyms {
                map.insert(*keysym, keycode);
            }
        }
    }
    map
}