Introduce IPC socket

crates/popcorn-d/Cargo.toml

@@ -21,6 +21,7 @@ toml = "0.9.8"
 popcorn-conf = { path = "../popcorn-conf" }
 serde = { version = "1.0.228", features = ["derive"] }
 popcorn-proto = { path = "../popcorn-proto" }
+bincode = "1.3.3"
 
 [build-dependencies]
 slint-build = "1.14.1"

crates/popcorn-d/src/ipc.rs

@@ -0,0 +1,56 @@
+use std::fs;
+use std::io::Read;
+use std::os::unix::net::{UnixListener, UnixStream};
+use std::path::PathBuf;
+use std::sync::mpsc::Sender;
+
+use dirs::runtime_dir;
+use popcorn_proto::OsdArgs;
+
+/// Start a Unix socket server and forward received messages to the UI thread.
+pub fn start_ipc(tx: Sender<OsdArgs>) -> std::io::Result<()> {
+    let sock_path = socket_path();
+
+    // Remove leftover socket from a previous run.
+    let _ = fs::remove_file(&sock_path);
+
+    // Create parent directory if missing.
+    if let Some(parent) = sock_path.parent() {
+        fs::create_dir_all(parent)?;
+    }
+
+    // Bind the Unix domain socket.
+    let listener = UnixListener::bind(&sock_path)?;
+
+    // Run the IPC accept loop in a background thread.
+    std::thread::spawn(move || {
+        // Accept short-lived connections.
+        for stream in listener.incoming() {
+            if let Ok(stream) = stream {
+                // Read one message per connection.
+                if let Ok(args) = read_message(stream) {
+                    // Forward to UI thread via channel.
+                    let _ = tx.send(args);
+                }
+            }
+        }
+    });
+
+    Ok(())
+}
+
+/// Read a single serialized OsdArgs message from a socket.
+fn read_message(mut stream: UnixStream) -> bincode::Result<OsdArgs> {
+    let mut buf = Vec::new();
+    // Read until client closes the connection.
+    stream.read_to_end(&mut buf)?;
+    // Deserialize binary message.
+    bincode::deserialize(&buf)
+}
+
+/// Compute the per-user runtime socket path.
+fn socket_path() -> PathBuf {
+    // Prefer XDG runtime dir. Fallback to /tmp.
+    let base = runtime_dir().unwrap_or_else(|| PathBuf::from("/tmp"));
+    base.join("candywidgets").join("popcorn.sock")
+}

crates/popcorn-d/src/main.rs

@@ -1,18 +1,38 @@
+mod ipc;
 mod osd;
 
 use osd::OsdUi;
 use popcorn_conf::PopcornConfig;
+use popcorn_proto::OsdArgs;
+
+use std::sync::mpsc;
 
 fn main() -> Result<(), Box<dyn std::error::Error>> {
+    // Load configuration once at startup.
     let cfg = PopcornConfig::load_or_default();
+
+    // Create the OSD UI on the main (UI) thread.
     let osd = OsdUi::new(&cfg)?;
 
-    // start IPC loop here
-    // for each message:
-    //   osd.update(&args, &cfg)
-    //   reset timer
+    // Channel used to send IPC messages to the UI thread.
+    let (tx, rx) = mpsc::channel::<OsdArgs>();
 
-    let _ = slint::run_event_loop();
+    // Start IPC server in a background thread.
+    ipc::start_ipc(tx)?;
 
+    // Poll IPC messages on the UI thread.
+    slint::Timer::default().start(
+        slint::TimerMode::Repeated,
+        std::time::Duration::from_millis(16),
+        move || {
+            // Process all pending messages.
+            while let Ok(args) = rx.try_recv() {
+                let _ = osd.update(&args, &cfg);
+            }
+        },
+    );
+
+    // Run the Slint event loop.
+    slint::run_event_loop();
     Ok(())
 }

crates/popcorn/Cargo.toml

@@ -12,5 +12,6 @@ keywords = ["OSD", "popup", "desktop", "cli"]
 license = "GPL-3+"
 
 [dependencies]
+bincode = "1.3.3"
 clap = { version = "4.5.53", features = ["derive"] }
 popcorn-proto = { path = "../popcorn-proto" }

crates/popcorn/src/main.rs

@@ -1,8 +1,8 @@
 mod args;
 
 use args::CliArgs;
-use popcorn_proto::OsdArgs;
 use clap::Parser;
+use popcorn_proto::OsdArgs;
 
 fn main() {
     let cli = CliArgs::parse();