Add ability to use kdotool as a dependency to upstream projects

Cargo.toml

@@ -9,6 +9,9 @@ keywords = ["xdotool", "wayland", "kde"]
 categories = ["command-line-utilities"]
 edition = "2024"
 
+[lib]
+path = "src/lib.rs"
+
 [profile.release]
 strip = true  # Automatically strip symbols from the binary.
 opt-level = "z"  # Optimize for size.

examples/active_window.rs

@@ -0,0 +1,18 @@
+fn main() {
+    match kdotool::get_active_window_info() {
+        Ok(info) => {
+            println!("id: {}", info.id);
+            println!("title: {}", info.title);
+            println!("class_name: {}", info.class_name);
+            println!("pid: {}", info.pid);
+            println!("x: {}", info.x);
+            println!("y: {}", info.y);
+            println!("width: {}", info.width);
+            println!("height: {}", info.height);
+        }
+        Err(err) => {
+            eprintln!("error: {err}");
+            std::process::exit(1);
+        }
+    }
+}

src/lib.rs

@@ -0,0 +1,227 @@
+use std::error::Error;
+use std::io::Write;
+use std::sync::mpsc;
+use std::time::{Duration, Instant, SystemTime, UNIX_EPOCH};
+
+use anyhow::{anyhow, Context};
+use dbus::{
+    blocking::{Connection, SyncConnection},
+    channel::MatchingReceiver,
+    message::MatchRule,
+};
+use serde::{Deserialize, Serialize};
+
+mod templates;
+use templates::{SCRIPT_FOOTER, SCRIPT_HEADER};
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ActiveWindowInfo {
+    pub id: String,
+    pub title: String,
+    pub class_name: String,
+    pub pid: u32,
+    pub x: f64,
+    pub y: f64,
+    pub width: f64,
+    pub height: f64,
+}
+
+#[derive(Default, Serialize)]
+struct Globals {
+    dbus_addr: String,
+    cmdline: String,
+    debug: bool,
+    kde5: bool,
+    marker: String,
+    script_name: String,
+    shortcut: String,
+}
+
+const STEP_ACTIVE_WINDOW_INFO: &str = r#"
+    output_debug("STEP getactivewindowinfo")
+    let w = workspace_activeWindow();
+    if (w == null) {
+        output_error("No active window");
+    } else {
+        output_result(JSON.stringify({
+            id: w.internalId,
+            title: w.caption,
+            class_name: w.resourceClass,
+            pid: w.pid,
+            x: w.x,
+            y: w.y,
+            width: w.width,
+            height: w.height
+        }));
+    }
+"#;
+
+pub fn get_active_window_info() -> Result<ActiveWindowInfo, Box<dyn Error + Send + Sync>> {
+    get_active_window_info_impl().map_err(|err| err.into())
+}
+
+fn get_active_window_info_impl() -> anyhow::Result<ActiveWindowInfo> {
+    let mut context = Globals {
+        cmdline: "kdotool::get_active_window_info".to_string(),
+        ..Default::default()
+    };
+
+    if let Ok(version) = std::env::var("KDE_SESSION_VERSION") {
+        if version == "5" {
+            context.kde5 = true;
+        }
+    }
+
+    let unique_suffix = SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .context("failed to read system time")?
+        .as_millis();
+    context.marker = format!("kdotool-lib-{unique_suffix}");
+    context.script_name = context.marker.clone();
+
+    // Establish the DBus listener connection first so we know the address
+    // to embed in the generated KWin script.
+    let self_conn = SyncConnection::new_session()?;
+    context.dbus_addr = self_conn.unique_name().to_string();
+
+    let script_contents = generate_script(&context)?;
+    let result_payload = run_script(&script_contents, &context, self_conn)?;
+    parse_active_window_info(&result_payload)
+}
+
+pub(crate) fn generate_script(globals: &Globals) -> anyhow::Result<String> {
+    let mut full_script = String::new();
+    let mut reg = handlebars::Handlebars::new();
+    reg.set_strict_mode(true);
+    let render_context = handlebars::Context::wraps(globals)?;
+
+    full_script.push_str(&reg.render_template_with_context(SCRIPT_HEADER, &render_context)?);
+    full_script.push_str(&reg.render_template_with_context(STEP_ACTIVE_WINDOW_INFO, &render_context)?);
+    full_script.push_str(&reg.render_template_with_context(SCRIPT_FOOTER, &render_context)?);
+
+    Ok(full_script)
+}
+
+pub(crate) fn run_script(script_contents: &str, context: &Globals, self_conn: SyncConnection) -> anyhow::Result<String> {
+    enum ScriptMessage {
+        Result(String),
+        Error(String),
+    }
+
+    let kwin_conn = Connection::new_session()?;
+    let kwin_proxy = kwin_conn.with_proxy("org.kde.KWin", "/Scripting", Duration::from_millis(5000));
+
+    let (tx, rx) = mpsc::channel();
+
+    let _receiver = self_conn.start_receive(
+        MatchRule::new_method_call(),
+        Box::new(move |message, _connection| -> bool {
+            if let Some(member) = message.member() {
+                if let Some(arg) = message.get1::<String>() {
+                    match member.as_ref() {
+                        "result" => {
+                            let _ = tx.send(ScriptMessage::Result(arg));
+                        }
+                        "error" => {
+                            let _ = tx.send(ScriptMessage::Error(arg));
+                        }
+                        _ => {}
+                    }
+                }
+            }
+            true
+        }),
+    );
+
+    let mut script_file = tempfile::NamedTempFile::with_prefix("kdotool-")?;
+    script_file.write_all(script_contents.as_bytes())?;
+    let script_file_path = script_file.into_temp_path();
+
+    let script_id: i32;
+    (script_id,) = kwin_proxy.method_call(
+        "org.kde.kwin.Scripting",
+        "loadScript",
+        (script_file_path.to_str().unwrap(), &context.script_name),
+    )?;
+    if script_id < 0 {
+        return Err(anyhow!(
+            "Failed to load script. A script with the same name may already exist."
+        ));
+    }
+
+    let script_proxy = kwin_conn.with_proxy(
+        "org.kde.KWin",
+        if context.kde5 {
+            format!("/{script_id}")
+        } else {
+            format!("/Scripting/Script{script_id}")
+        },
+        Duration::from_millis(5000),
+    );
+
+    let _: () = script_proxy.method_call("org.kde.kwin.Script", "run", ())?;
+    let _: () = script_proxy.method_call("org.kde.kwin.Script", "stop", ())?;
+
+    let start = Instant::now();
+    let timeout = Duration::from_secs(5);
+
+    let result = loop {
+        self_conn.process(Duration::from_millis(100))?;
+        match rx.try_recv() {
+            Ok(ScriptMessage::Result(payload)) => break Ok(payload),
+            Ok(ScriptMessage::Error(message)) => {
+                break Err(anyhow!("KWin script error: {message}"));
+            }
+            Err(mpsc::TryRecvError::Empty) => {
+                if start.elapsed() > timeout {
+                    break Err(anyhow!("Timed out waiting for KWin response"));
+                }
+            }
+            Err(mpsc::TryRecvError::Disconnected) => {
+                break Err(anyhow!("KWin response channel disconnected"));
+            }
+        }
+    };
+
+    let _: Result<(), _> = kwin_proxy.method_call(
+        "org.kde.kwin.Scripting",
+        "unloadScript",
+        (&context.script_name,),
+    );
+
+    result
+}
+
+pub(crate) fn parse_active_window_info(payload: &str) -> anyhow::Result<ActiveWindowInfo> {
+    // KWin sends JSON.stringify output as a DBus string, which arrives with
+    // escaped inner quotes. Try parsing directly first; if that fails, try
+    // interpreting as a JSON string literal to unescape it.
+    serde_json::from_str(payload)
+        .or_else(|_| {
+            let unescaped: String = serde_json::from_str(payload)
+                .context("failed to unescape payload")?;
+            serde_json::from_str(&unescaped)
+                .context("failed to parse unescaped payload")
+        })
+        .context("failed to parse active window info")
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn parses_active_window_info() {
+        let payload = r#"{"id":"0x123","title":"Terminal","class_name":"konsole","pid":4242,"x":10,"y":20,"width":800,"height":600}"#;
+        let info = parse_active_window_info(payload).expect("should parse payload");
+
+        assert_eq!(info.id, "0x123");
+        assert_eq!(info.title, "Terminal");
+        assert_eq!(info.class_name, "konsole");
+        assert_eq!(info.pid, 4242);
+        assert!((info.x - 10.0).abs() < f64::EPSILON);
+        assert!((info.y - 20.0).abs() < f64::EPSILON);
+        assert!((info.width - 800.0).abs() < f64::EPSILON);
+        assert!((info.height - 600.0).abs() < f64::EPSILON);
+    }
+}