feat: add authenticated IPC and feresectl

feresectl/src/main.rs

@@ -0,0 +1,108 @@
+use std::env;
+use std::error::Error;
+use std::io;
+use std::os::unix::net::UnixStream;
+use std::path::PathBuf;
+
+use ferese_ipc::{Request, Response, VERSION, read_frame, write_frame};
+use serde_json::{Value, json};
+
+fn main() -> Result<(), Box<dyn Error>> {
+    let (command, args) = parse_args(env::args().skip(1))?;
+    let request = Request {
+        version: VERSION,
+        id: 1,
+        kind: "command".to_owned(),
+        command,
+        args,
+    };
+    let mut stream = UnixStream::connect(socket_path()?)?;
+
+    write_frame(&mut stream, &request)?;
+    let response: Response = read_frame(&mut stream)?;
+    if let Some(error) = response.error {
+        return Err(format!("{}: {}", error.code, error.message).into());
+    }
+
+    println!(
+        "{}",
+        serde_json::to_string_pretty(&response.result.unwrap_or(Value::Null))?
+    );
+    Ok(())
+}
+
+fn parse_args(args: impl IntoIterator<Item = String>) -> Result<(String, Value), String> {
+    let mut args = args.into_iter();
+    let command = args.next().ok_or_else(usage)?;
+    let positional = args.collect::<Vec<_>>();
+    let payload = match command.as_str() {
+        "focus" | "move" | "resize" => {
+            exactly_one(&command, &positional, "direction")?;
+            json!({ "direction": positional[0] })
+        }
+        "workspace" | "move-to-workspace" => {
+            exactly_one(&command, &positional, "index")?;
+            let index = positional[0]
+                .parse::<u32>()
+                .map_err(|_| format!("{} requires a positive workspace index", command))?;
+            json!({ "index": index })
+        }
+        "toggle-floating" | "toggle-fullscreen" | "close" | "get-focused-window"
+        | "get-workspaces" | "get-outputs" => {
+            if !positional.is_empty() {
+                return Err(format!("{command} does not accept arguments"));
+            }
+            json!({})
+        }
+        _ => return Err(format!("unknown command {command:?}\n{}", usage())),
+    };
+
+    Ok((command, payload))
+}
+
+fn exactly_one(command: &str, args: &[String], name: &str) -> Result<(), String> {
+    if args.len() == 1 {
+        Ok(())
+    } else {
+        Err(format!("{command} requires exactly one {name}"))
+    }
+}
+
+fn socket_path() -> Result<PathBuf, io::Error> {
+    env::var_os("XDG_RUNTIME_DIR")
+        .filter(|value| !value.is_empty())
+        .map(PathBuf::from)
+        .map(|directory| directory.join("ferese/control.sock"))
+        .ok_or_else(|| io::Error::new(io::ErrorKind::NotFound, "XDG_RUNTIME_DIR is not set"))
+}
+
+fn usage() -> String {
+    "usage: feresectl <focus|move|resize> <direction>\n       feresectl <workspace|move-to-workspace> <index>\n       feresectl <toggle-floating|toggle-fullscreen|close|get-focused-window|get-workspaces|get-outputs>".to_owned()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn parses_direction_and_workspace_commands() {
+        assert_eq!(
+            parse_args(["focus".to_owned(), "left".to_owned()])
+                .unwrap()
+                .1,
+            json!({ "direction": "left" })
+        );
+        assert_eq!(
+            parse_args(["workspace".to_owned(), "7".to_owned()])
+                .unwrap()
+                .1,
+            json!({ "index": 7 })
+        );
+    }
+
+    #[test]
+    fn rejects_unknown_or_missing_arguments() {
+        assert!(parse_args(["focus".to_owned()]).is_err());
+        assert!(parse_args(["reload-config".to_owned()]).is_err());
+    }
+}