feat(theme): add sway bar color integration

[him-cyber]

Summary

This PR introduces optional integration with the user's Sway configuration to automatically apply bar colors (background and foreground) from the ~/.config/sway/config file. Fix for the open issue #2145

Motivation

As a Wayland-native window manager, Sway allows defining custom bar colors. This enhancement bridges the theme configuration in i3status-rust with Sway’s color settings, improving visual consistency and user experience for Sway users.

Implementation

• Introduced a sway_integration section in config.toml
• Parsed Sway bar colors (background, statusline) from the local Sway config
• Applied parsed colors to the theme's idle_bg and idle_fg fields
• Added necessary Rust glue code with minimal footprint

Config Usage

To enable this, add to your config.toml:

[sway_integration]
use_sway_bar_colors = true

[bim9262]

Instead of trying to read the config from disk, I'd recommend using swayipc_async to get the values.

Here's a toy program that reads the background and statusline colors:

use swayipc_async::Connection;

#[tokio::main]
async fn main() {
    let mut connection = Connection::new().await.unwrap();
    if let Some(bar_id) = connection.get_bar_ids().await.unwrap().first() {
        let bar_config = connection.get_bar_config(bar_id).await.unwrap();
        println!(
            "Bar config for {}: background {:?} statusline {:?}",
            bar_id, bar_config.colors.background, bar_config.colors.statusline
        );
    }
}

Here's another extension of this that finds the bar id for the current i3status-rust that's running:

use std::{os::unix::process::parent_id, path::Path};
use swayipc_async::Connection;
use tokio::io::AsyncReadExt as _;

pub async fn read_file(path: impl AsRef<Path>) -> std::io::Result<String> {
    let mut file = tokio::fs::File::open(path).await?;
    let mut content = String::new();
    file.read_to_string(&mut content).await?;
    Ok(content.trim_end().to_string())
}

#[tokio::main]
async fn main() {
    let mut connection = Connection::new().await.unwrap();
    eprintln!("Parent process ID: {}", parent_id());
    let ppid_stat = read_file(
        Path::new("/proc")
            .join(parent_id().to_string())
            .join("stat"),
    )
    .await
    .unwrap();
    let grandppid = ppid_stat.split(' ').nth(3).unwrap();
    eprintln!("Grandparent process ID: {}", grandppid);
    let grandppid_cmdline = read_file(Path::new("/proc").join(grandppid).join("cmdline"))
        .await
        .unwrap();
    let grandppid_cmdline_parts: Vec<_> = grandppid_cmdline.split('\0').collect();
    if let Some(bar_id) = grandppid_cmdline_parts
        .iter()
        .position(|&s| s == "-b" || s == "--bar_id")
        .and_then(|pos| grandppid_cmdline_parts.get(pos + 1))
    {
        let bar_config = connection.get_bar_config(&bar_id).await.unwrap();
        eprintln!(
            "Bar config for {}: background {:?} statusline {:?}",
            bar_id, bar_config.colors.background, bar_config.colors.statusline
        );
    }

    println!("{{\"version\": 1, \"click_events\": true}}\n[");
    loop {
        println!("[],")
    }
}

This will be able to get the arguments that are used to start bar:

(excerpt from pstree -ap)

  |           |-swaybar,2147460 -b bar-1
  |           |   |-sh,2147520 -c /tmp/sway_test/target/debug/sway_test 2> /tmp/l
  |           |   |   `-sway_test,2147521

and the sway config:

set $background #ffdddd
bar {
  position top
  strip_workspace_numbers yes
  height $bar_height
  status_padding 0

  # When the status_command prints a new line to stdout, swaybar updates.
  status_command /tmp/sway_test/target/debug/sway_test 2> /tmp/l

  colors {
          background $background
          statusline #222222
          separator #666666

  #                          border  backgr. text
          focused_workspace #0088CC #0088CC #ffffff
          active_workspace #333333 #333333 #ffffff
          inactive_workspace #333333 #333333 #888888
          urgent_workspace #2f343a #900000 #ffffff
  }
}