Create tcp server

src/app.rs

@@ -18,7 +18,7 @@ use crate::{
     emulator::{EmulatorClient, EmulatorCommand, SimId},
     input::MappingProvider,
     persistence::Persistence,
-    window::{AboutWindow, AppWindow, GameWindow, InputWindow},
+    window::{AboutWindow, AppWindow, GameWindow, GdbServerWindow, InputWindow},
 };
 
 fn load_icon() -> anyhow::Result<IconData> {
@@ -183,6 +183,10 @@ impl ApplicationHandler<UserEvent> for Application {
                 let about = AboutWindow;
                 self.open(event_loop, Box::new(about));
             }
+            UserEvent::OpenDebugger(sim_id) => {
+                let debugger = GdbServerWindow::new(sim_id, self.client.clone());
+                self.open(event_loop, Box::new(debugger));
+            }
             UserEvent::OpenInput => {
                 let input = InputWindow::new(self.mappings.clone());
                 self.open(event_loop, Box::new(input));
@@ -374,6 +378,7 @@ impl Drop for Viewport {
 pub enum UserEvent {
     GamepadEvent(gilrs::Event),
     OpenAbout,
+    OpenDebugger(SimId),
     OpenInput,
     OpenPlayer2,
 }

src/emulator.rs

@@ -1,5 +1,6 @@
 use std::{
     collections::HashMap,
+    fmt::Display,
     fs::{self, File},
     io::{Read, Seek, SeekFrom, Write},
     path::{Path, PathBuf},
@@ -45,6 +46,14 @@ impl SimId {
         }
     }
 }
+impl Display for SimId {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str(match self {
+            Self::Player1 => "Player 1",
+            Self::Player2 => "Player 2",
+        })
+    }
+}
 
 struct Cart {
     rom_path: PathBuf,

src/gdbserver.rs

@@ -0,0 +1,154 @@
+use std::{
+    error::Error,
+    sync::{Arc, Mutex},
+    thread,
+};
+use tokio::{
+    io::{AsyncReadExt, AsyncWriteExt as _, BufReader, BufWriter},
+    net::{
+        tcp::{OwnedReadHalf, OwnedWriteHalf},
+        TcpListener, TcpStream,
+    },
+    select,
+    sync::oneshot,
+};
+
+use crate::emulator::{EmulatorClient, EmulatorCommand, SimId};
+
+pub struct GdbServer {
+    sim_id: SimId,
+    client: EmulatorClient,
+    status: Arc<Mutex<GdbServerStatus>>,
+    killer: Option<oneshot::Sender<()>>,
+}
+
+impl GdbServer {
+    pub fn new(sim_id: SimId, client: EmulatorClient) -> Self {
+        Self {
+            sim_id,
+            client,
+            status: Arc::new(Mutex::new(GdbServerStatus::Stopped)),
+            killer: None,
+        }
+    }
+
+    pub fn status(&self) -> GdbServerStatus {
+        self.status.lock().unwrap().clone()
+    }
+
+    pub fn start(&mut self, port: u16) {
+        let sim_id = self.sim_id;
+        let client = self.client.clone();
+        let status = self.status.clone();
+        let (tx, rx) = oneshot::channel();
+        self.killer = Some(tx);
+        thread::spawn(move || {
+            tokio::runtime::Builder::new_current_thread()
+                .enable_all()
+                .build()
+                .unwrap()
+                .block_on(async move {
+                    select! {
+                        _ = run_server(sim_id, client, port, &status) => {}
+                        _ = rx => {
+                            *status.lock().unwrap() = GdbServerStatus::Stopped;
+                        }
+                    }
+                })
+        });
+    }
+
+    pub fn stop(&mut self) {
+        if let Some(killer) = self.killer.take() {
+            let _ = killer.send(());
+        }
+    }
+}
+
+async fn run_server(
+    sim_id: SimId,
+    client: EmulatorClient,
+    port: u16,
+    status: &Mutex<GdbServerStatus>,
+) {
+    client.send_command(EmulatorCommand::Pause);
+    let Some(stream) = try_connect(port, status).await else {
+        return;
+    };
+    let connection = GdbConnection::new(sim_id, client, stream);
+    match connection.run().await {
+        Ok(()) => {
+            *status.lock().unwrap() = GdbServerStatus::Stopped;
+        }
+        Err(error) => {
+            *status.lock().unwrap() = GdbServerStatus::Error(error.to_string());
+        }
+    }
+}
+
+async fn try_connect(port: u16, status: &Mutex<GdbServerStatus>) -> Option<TcpStream> {
+    *status.lock().unwrap() = GdbServerStatus::Connecting;
+    let listener = match TcpListener::bind(("127.0.0.1", port)).await {
+        Ok(l) => l,
+        Err(err) => {
+            *status.lock().unwrap() = GdbServerStatus::Error(err.to_string());
+            return None;
+        }
+    };
+    match listener.accept().await {
+        Ok((stream, _)) => {
+            *status.lock().unwrap() = GdbServerStatus::Running;
+            Some(stream)
+        }
+        Err(err) => {
+            *status.lock().unwrap() = GdbServerStatus::Error(err.to_string());
+            None
+        }
+    }
+}
+
+#[derive(Clone)]
+pub enum GdbServerStatus {
+    Stopped,
+    Connecting,
+    Running,
+    Error(String),
+}
+
+impl GdbServerStatus {
+    pub fn running(&self) -> bool {
+        matches!(self, Self::Connecting | Self::Running)
+    }
+}
+
+struct GdbConnection {
+    sim_id: SimId,
+    client: EmulatorClient,
+    stream_in: BufReader<OwnedReadHalf>,
+    stream_out: BufWriter<OwnedWriteHalf>,
+}
+
+impl GdbConnection {
+    fn new(sim_id: SimId, client: EmulatorClient, stream: TcpStream) -> Self {
+        let (rx, tx) = stream.into_split();
+        Self {
+            sim_id,
+            client,
+            stream_in: BufReader::new(rx),
+            stream_out: BufWriter::new(tx),
+        }
+    }
+    async fn run(mut self) -> Result<(), Box<dyn Error>> {
+        println!("Connected for {}", self.sim_id);
+        self.client.send_command(EmulatorCommand::Resume);
+        loop {
+            let byte = self.read_byte().await?;
+            println!("{byte}");
+            self.stream_out.write_u8(byte).await?;
+        }
+    }
+
+    async fn read_byte(&mut self) -> std::io::Result<u8> {
+        self.stream_in.read_u8().await
+    }
+}

src/main.rs

@@ -14,6 +14,7 @@ mod app;
 mod audio;
 mod controller;
 mod emulator;
+mod gdbserver;
 mod graphics;
 mod input;
 mod persistence;

src/window.rs

@@ -1,12 +1,14 @@
 pub use about::AboutWindow;
 use egui::{Context, ViewportBuilder, ViewportId};
 pub use game::GameWindow;
+pub use gdb::GdbServerWindow;
 pub use input::InputWindow;
 use winit::event::KeyEvent;
 
 mod about;
 mod game;
 mod game_screen;
+mod gdb;
 mod input;
 
 pub trait AppWindow {

src/window/game.rs

@@ -121,6 +121,14 @@ impl GameWindow {
                 }
             }
         });
+        ui.menu_button("Tools", |ui| {
+            if ui.button("GDB Server").clicked() {
+                self.proxy
+                    .send_event(UserEvent::OpenDebugger(self.sim_id))
+                    .unwrap();
+                ui.close_menu();
+            }
+        });
         ui.menu_button("About", |ui| {
             self.proxy.send_event(UserEvent::OpenAbout).unwrap();
             ui.close_menu();

src/window/gdb.rs

@@ -0,0 +1,80 @@
+use egui::{Button, CentralPanel, TextEdit, ViewportBuilder, ViewportId};
+
+use crate::{
+    emulator::{EmulatorClient, SimId},
+    gdbserver::{GdbServer, GdbServerStatus},
+};
+
+use super::AppWindow;
+
+pub struct GdbServerWindow {
+    sim_id: SimId,
+    port_str: String,
+    server: GdbServer,
+}
+
+impl GdbServerWindow {
+    pub fn new(sim_id: SimId, client: EmulatorClient) -> Self {
+        Self {
+            sim_id,
+            port_str: (8080 + sim_id.to_index()).to_string(),
+            server: GdbServer::new(sim_id, client),
+        }
+    }
+}
+
+impl AppWindow for GdbServerWindow {
+    fn viewport_id(&self) -> ViewportId {
+        ViewportId::from_hash_of(format!("Debugger-{}", self.sim_id))
+    }
+
+    fn initial_viewport(&self) -> ViewportBuilder {
+        ViewportBuilder::default()
+            .with_title(format!("GDB Server ({})", self.sim_id))
+            .with_inner_size((300.0, 200.0))
+    }
+
+    fn show(&mut self, ctx: &egui::Context) {
+        let port_num: Option<u16> = self.port_str.parse().ok();
+        let status = self.server.status();
+        CentralPanel::default().show(ctx, |ui| {
+            ui.horizontal(|ui| {
+                if port_num.is_none() {
+                    let style = ui.style_mut();
+                    let error = style.visuals.error_fg_color;
+                    style.visuals.widgets.active.bg_stroke.color = error;
+                    style.visuals.widgets.hovered.bg_stroke.color = error;
+                }
+                ui.label("Port");
+                let port_editor = TextEdit::singleline(&mut self.port_str).desired_width(100.0);
+                ui.add_enabled(!status.running(), port_editor);
+            });
+
+            if !status.running() {
+                let start_button = Button::new("Start");
+                if ui.add_enabled(port_num.is_some(), start_button).clicked() {
+                    let port = port_num.unwrap();
+                    self.server.start(port);
+                }
+            } else {
+                let stop_button = Button::new("Stop");
+                if ui.add(stop_button).clicked() {
+                    self.server.stop();
+                }
+            }
+
+            match &status {
+                GdbServerStatus::Stopped => {}
+                GdbServerStatus::Connecting => {
+                    ui.label("Connecting...");
+                }
+                GdbServerStatus::Running => {
+                    ui.label("Running");
+                }
+                GdbServerStatus::Error(message) => {
+                    ui.label(message);
+                }
+            }
+        });
+    }
+}