feat: wayland connection, niri IPC and valw doctor

src/niri.rs

@@ -0,0 +1,61 @@
+use anyhow::{Context, Result, anyhow};
+use niri_ipc::{Request, Response, socket::Socket};
+
+/// The niri release the pinned `niri-ipc` crate belongs to. Keep in sync
+/// with the `niri-ipc = "=X.Y.0"` line in Cargo.toml (a test checks this).
+pub const IPC_VERSION: (u32, u32) = (26, 4);
+
+fn request(request: Request) -> Result<Response> {
+    let mut socket =
+        Socket::connect().context("could not connect to niri (is NIRI_SOCKET set?)")?;
+    socket
+        .send(request)
+        .context("niri IPC request failed")?
+        .map_err(|e| anyhow!("niri replied with an error: {e}"))
+}
+
+/// Name of the output niri has focused, if any.
+pub fn focused_output() -> Result<Option<String>> {
+    match request(Request::FocusedOutput)? {
+        Response::FocusedOutput(output) => Ok(output.map(|o| o.name)),
+        other => Err(anyhow!("unexpected niri reply: {other:?}")),
+    }
+}
+
+/// niri's version string, e.g. "26.04 (Nixpkgs)".
+pub fn version() -> Result<String> {
+    match request(Request::Version)? {
+        Response::Version(v) => Ok(v),
+        other => Err(anyhow!("unexpected niri reply: {other:?}")),
+    }
+}
+
+/// `(year, month)` from a niri version string like "26.04 (Nixpkgs)".
+pub fn parse_version(v: &str) -> Option<(u32, u32)> {
+    let (year, rest) = v.split_once('.')?;
+    let month: String = rest.chars().take_while(char::is_ascii_digit).collect();
+    Some((year.parse().ok()?, month.parse().ok()?))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn parses_versions() {
+        assert_eq!(parse_version("26.04 (Nixpkgs)"), Some((26, 4)));
+        assert_eq!(parse_version("25.11"), Some((25, 11)));
+        assert_eq!(parse_version("26.04.1-dev"), Some((26, 4)));
+        assert_eq!(parse_version("unknown"), None);
+    }
+
+    #[test]
+    fn ipc_version_matches_cargo_toml() {
+        let (y, m) = IPC_VERSION;
+        let pin = format!("niri-ipc = \"={y}.{m}.0\"");
+        assert!(
+            include_str!("../Cargo.toml").contains(&pin),
+            "Cargo.toml should pin {pin}"
+        );
+    }
+}