feat: lockfile to prevent overlapping locks

Cargo.toml

@@ -12,6 +12,7 @@ calloop = { version = "0.13.0" }
 chrono = "0.4.38"
 clap = { version = "4.5.4", features = ["derive"] }
 env_logger = "0.11.2"
+filelock-rs = "0.1.0-beta.2"
 futures-intrusive = "0.5.0"
 iced_runtime = "0.12.1"
 iced_wgpu = { version = "0.12.1", features = ["image"] }

src/main.rs

@@ -9,6 +9,7 @@ mod config;
 mod event;
 mod graphics;
 mod lock;
+mod pid;
 
 use crate::config::{Config, Settings};
 
@@ -112,12 +113,12 @@ impl Cli {
 }
 
 fn main() -> Result<()> {
-    // enable log and set default level
-    if std::env::var("RUST_LOG").is_err() {
-        std::env::set_var("RUST_LOG", "info");
-    }
     env_logger::init();
 
+    // ensure only one lock instance runs at a time
+    println!("making lock?");
+    let _lock = pid::PidLock::new()?;
+
     // parse cli and run lockscreen
     let cli = Cli::parse();
     let settings = cli.settings()?;

src/pid.rs

@@ -0,0 +1,33 @@
+//! PidLock Implementation
+
+use std::fs::{remove_file, File};
+use std::path::PathBuf;
+
+use anyhow::{Context, Result};
+use filelock_rs::FdLock;
+
+pub struct PidLock {
+    path: PathBuf,
+    lock: File,
+}
+
+impl PidLock {
+    pub fn new() -> Result<Self> {
+        let path = xdg::BaseDirectories::new()
+            .context("failed to read xdg base-dirs")?
+            .get_runtime_file("dynlock.lock")
+            .context("failed to locate lockfile")?;
+        println!("path {path:?}");
+        let lock = File::create(&path).context("failed to create lockfile")?;
+        lock.try_lock_exclusive()
+            .context("failed to lock lockfile")?;
+        Ok(Self { path, lock })
+    }
+}
+
+impl Drop for PidLock {
+    fn drop(&mut self) {
+        self.lock.unlock().expect("failed to unlock lockfile");
+        remove_file(&self.path).expect("failed to remove lockfile");
+    }
+}