gd-wireportal-full/rust/src/portals/screencast.rs

use ashpd::desktop::{
    screencast::{CursorMode, Screencast, SourceType},
    PersistMode,
};
use gdext_coroutines::prelude::*;
use godot::prelude::*;
use godot_tokio::AsyncRuntime;
use smol::{channel, lock::Mutex};
use std::sync::Arc;

#[derive(GodotClass)]
#[class(base = Node)]
/// Runner node for requesting a pipewire screencast
struct ScreencastRunner {
    base: Base<Node>,
    runner: Arc<Mutex<Runner>>,
    receiver: channel::Receiver<Result<u32, String>>,
    sender: channel::Sender<Result<u32, String>>,
    last_result: Option<Result<u32, String>>,
}

struct Runner;

#[godot_api]
impl INode for ScreencastRunner {
    fn init(base: Base<Node>) -> Self {
        #[cfg(not(target_os = "linux"))]
        panic!("Not supported on Windows");
        let (sender, receiver) = channel::unbounded();
        Self {
            base,
            receiver,
            sender,
            runner: Arc::new(Mutex::new(Runner {})),
            last_result: None,
        }
    }

    fn process(&mut self, _delta: f64) {
        let channel_elements = self.receiver.len();
        for _ in 0..channel_elements {
            let result = self.receiver.recv();
            let result = AsyncRuntime::block_on(result)
                .expect("Failed to receive screencast request result");
            self.last_result = Some(result.clone());
            match result {
                Ok(pipewire_node_id) => self
                    .base_mut()
                    .emit_signal("screencast_sucess", &[pipewire_node_id.to_variant()]),
                Err(reason) => self
                    .base_mut()
                    .emit_signal("screencast_failure", &[reason.to_variant()]),
            };
        }
    }
}

#[godot_api]
impl ScreencastRunner {
    /// Emited after a request to capture a window, if that request is successful.
    /// Contains the id of the pipewire node with the stream
    #[signal]
    fn screencast_sucess(pipewire_node_id: u32);
    /// Emited after a request to capture a window, if that request has failed.
    /// Contains the reason (as string) for why the request failed
    #[signal]
    fn screencast_failure(reason: String);
    /// Emited after a request to capture a window completes
    /// pipe_wire_node_id will contain the id of the pipewire node with the stream if ok is true
    /// reason will contain the reason (as String) why the request failed if ok is false
    /// ok indicates whether the request was successful or not
    #[signal]
    fn screencast_result(pipewire_node_id: u32, reason: String, ok: bool);
    /// Request a new window/screen capture from the user.
    /// Returns the async runner node.
    /// You can either await the `completed` result on that node
    #[func]
    fn request_capture(&mut self) -> Gd<SpireCoroutine> {
        let sender = self.sender.clone();
        let binding = self.runner.clone();
        // This is cursed. First having to spawn the task on the background runtime
        let x = AsyncRuntime::spawn(async move {
            let runner = binding.lock().await;
            runner.run_capture(sender).await;
        });
        // And then using the engine's runtime to await the completion in the background
        self.start_async_task(async move {
            let _ = x.await;
        })
    }
}
impl Runner {
    async fn run_capture(&self, result_chan: smol::channel::Sender<Result<u32, String>>) {
        let proxy = Screencast::new().await.expect("Screencast proxy failed");
        let session = match proxy.create_session().await {
            Ok(x) => x,
            Err(err) => {
                godot_warn!("Failed to create session: {}", err);
                return;
            }
        };
        match proxy
            .select_sources(
                &session,
                CursorMode::Metadata,
                SourceType::Monitor | SourceType::Window,
                true,
                None,
                PersistMode::DoNot,
            )
            .await
        {
            Ok(_) => {}
            Err(err) => {
                godot_warn!("Err while selecting source: {}", err);
                return;
            }
        }

        let starter = match proxy.start(&session, None).await {
            Ok(x) => x,
            Err(err) => {
                godot_warn!("Error while starting: {}", err);
                return;
            }
        };
        let result = match starter.response() {
            Ok(x) => x,
            Err(err) => {
                godot_warn!("Err for response: {}", err);
                return;
            }
        };
        godot_print!("Got response");
        // This is ugly. But I can't await inside for_each
        // so instead just collect all futures and await them in a manual loop
        let things: Vec<_> = result
            .streams()
            .iter()
            .map(|stream| {
                godot_print!("node id: {}", stream.pipe_wire_node_id());
                godot_print!("size: {:?}", stream.size());
                godot_print!("position: {:?}", stream.position());
                result_chan.send(Ok(stream.pipe_wire_node_id()))
            })
            .collect();
        for future in things {
            let _ = future.await;
        }
    }
}