Initial commit

Signed-off-by: reisub0 <reisub0@gmail.com>

.gitignore

@@ -0,0 +1,15 @@
+/target
+**/*.rs.bk
+
+# create by https://github.com/iamcco/coc-gitignore (Sat Dec 07 2019 04:18:05 GMT+0530 (India Standard Time))
+# Rust.gitignore:
+# Generated by Cargo
+# will have compiled files and executables
+/target/
+
+# Remove Cargo.lock from gitignore if creating an executable, leave it for libraries
+# More information here https://doc.rust-lang.org/cargo/guide/cargo-toml-vs-cargo-lock.html
+Cargo.lock
+
+# These are backup files generated by rustfmt
+**/*.rs.bk

Cargo.toml

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+[package]
+name = "sway-alttab"
+version = "0.1.0"
+authors = ["reisub0 <reisub0@gmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+swayipc = {"version" = "^2.2.3", "features" = ["async"]}
+signal-hook = {"version" = "^0.1"}

src/main.rs

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+use std::sync::{Arc, Mutex};
+
+use swayipc::reply::Event::Window;
+use swayipc::reply::WindowChange;
+use swayipc::{block_on, Connection, EventType};
+
+type Res<T> = std::result::Result<T, Box<dyn std::error::Error>>;
+
+async fn get_current_focused_id() -> i64 {
+    Connection::new()
+        .await
+        .unwrap()
+        .get_tree()
+        .await
+        .unwrap()
+        .find_focused_as_ref(|n| n.focused)
+        .unwrap()
+        .id
+}
+
+fn handle_signal(last_focused: &Arc<Mutex<i64>>) {
+    block_on(async {
+        Connection::new()
+            .await
+            .unwrap()
+            .run_command(format!(
+                "[con_id={}] focus",
+                (*last_focused).lock().unwrap()
+            ))
+            .await
+            .unwrap();
+    })
+}
+
+fn main() -> Res<()> {
+    block_on(async {
+        let subs = [EventType::Window];
+        let sub = Connection::new().await?;
+        let mut events = sub.subscribe(&subs).await?;
+
+        let last_focus = Arc::new(Mutex::new(0));
+        let mut cur_focus = get_current_focused_id().await;
+        let clone = Arc::clone(&last_focus);
+
+        unsafe { signal_hook::register(signal_hook::SIGUSR1, move || handle_signal(&clone))? };
+        loop {
+            let event = events.next().await?;
+            if let Window(ev) = event {
+                if ev.change == WindowChange::Focus {
+                    let mut last = last_focus.lock().unwrap();
+                    *last = cur_focus;
+                    cur_focus = ev.container.id;
+                }
+            }
+        }
+    })
+}