Support manual/automatic ROM reloading

Cargo.lock

@@ -1449,6 +1449,15 @@ dependencies = [
  "windows-sys 0.59.0",
 ]
 
+[[package]]
+name = "fsevent-sys"
+version = "4.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "76ee7a02da4d231650c7cea31349b889be2f45ddb3ef3032d2ec8185f6313fd2"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "futures-channel"
 version = "0.3.31"
@@ -2157,6 +2166,26 @@ version = "3.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e2db585e1d738fc771bf08a151420d3ed193d9d895a36df7f6f8a9456b911ddc"
 
+[[package]]
+name = "kqueue"
+version = "1.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "eac30106d7dce88daf4a3fcb4879ea939476d5074a9b7ddd0fb97fa4bed5596a"
+dependencies = [
+ "kqueue-sys",
+ "libc",
+]
+
+[[package]]
+name = "kqueue-sys"
+version = "1.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ed9625ffda8729b85e45cf04090035ac368927b8cebc34898e7c120f52e4838b"
+dependencies = [
+ "bitflags 1.3.2",
+ "libc",
+]
+
 [[package]]
 name = "lazy_static"
 version = "1.5.0"
@@ -2189,6 +2218,7 @@ dependencies = [
  "image",
  "itertools 0.14.0",
  "normpath",
+ "notify",
  "num-derive",
  "num-traits",
  "object 0.37.3",
@@ -2482,6 +2512,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "78bed444cc8a2160f01cbcf811ef18cac863ad68ae8ca62092e8db51d51c761c"
 dependencies = [
  "libc",
+ "log",
  "wasi 0.11.1+wasi-snapshot-preview1",
  "windows-sys 0.59.0",
 ]
@@ -2624,6 +2655,30 @@ dependencies = [
  "windows-sys 0.59.0",
 ]
 
+[[package]]
+name = "notify"
+version = "8.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4d3d07927151ff8575b7087f245456e549fea62edf0ec4e565a5ee50c8402bc3"
+dependencies = [
+ "bitflags 2.9.3",
+ "fsevent-sys",
+ "inotify",
+ "kqueue",
+ "libc",
+ "log",
+ "mio",
+ "notify-types",
+ "walkdir",
+ "windows-sys 0.60.2",
+]
+
+[[package]]
+name = "notify-types"
+version = "2.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5e0826a989adedc2a244799e823aece04662b66609d96af8dff7ac6df9a8925d"
+
 [[package]]
 name = "nu-ansi-term"
 version = "0.46.0"

Cargo.toml

@@ -29,6 +29,7 @@ hex = "0.4"
 image = { version = "0.25", default-features = false, features = ["png"] }
 itertools = "0.14"
 normpath = "1"
+notify = "8"
 num-derive = "0.4"
 num-traits = "0.2"
 object = "0.37"

src/config.rs

@@ -26,7 +26,7 @@ pub struct CliArgs {
     #[arg(short, long)]
     pub object_data: bool,
     /// Open worlds window
-    #[arg(short, long)]
+    #[arg(long)]
     pub worlds: bool,
     /// Open frame buffers window
     #[arg(short, long)]
@@ -37,6 +37,9 @@ pub struct CliArgs {
     /// Open terminal
     #[arg(short, long)]
     pub terminal: bool,
+    /// Watch ROM files for changes, automatically reload
+    #[arg(short, long)]
+    pub watch: bool,
 }
 
 pub const COLOR_PRESETS: [[Color32; 2]; 3] = [

src/emulator.rs

@@ -5,7 +5,7 @@ use std::{
     sync::{
         Arc, Weak,
         atomic::{AtomicBool, Ordering},
-        mpsc::{self, RecvError, TryRecvError},
+        mpsc::{self, RecvTimeoutError, TryRecvError},
     },
     time::Duration,
 };
@@ -75,6 +75,7 @@ pub struct EmulatorBuilder {
     audio_on: Arc<[AtomicBool; 2]>,
     linked: Arc<AtomicBool>,
     start_paused: bool,
+    watch_rom: Arc<[AtomicBool; 2]>,
 }
 
 impl EmulatorBuilder {
@@ -91,11 +92,13 @@ impl EmulatorBuilder {
             audio_on: Arc::new([AtomicBool::new(true), AtomicBool::new(true)]),
             linked: Arc::new(AtomicBool::new(false)),
             start_paused: false,
+            watch_rom: Arc::new([AtomicBool::new(false), AtomicBool::new(false)]),
         };
         let client = EmulatorClient {
             queue,
             sim_state: builder.sim_state.clone(),
             state: builder.state.clone(),
+            watch_rom: builder.watch_rom.clone(),
             linked: builder.linked.clone(),
         };
         (builder, client)
@@ -121,12 +124,19 @@ impl EmulatorBuilder {
         self
     }
 
+    pub fn with_watch_rom(self, p1: bool, p2: bool) -> Self {
+        self.watch_rom[0].store(p1, Ordering::Relaxed);
+        self.watch_rom[1].store(p2, Ordering::Relaxed);
+        self
+    }
+
     pub fn build(self) -> Result<Emulator> {
         let mut emulator = Emulator::new(
             self.commands,
             self.sim_state,
             self.state,
             self.audio_on,
+            self.watch_rom,
             self.linked,
         )?;
         if let Some(path) = self.rom {
@@ -147,6 +157,7 @@ pub struct Emulator {
     sim_state: Arc<[Atomic<SimState>; 2]>,
     state: Arc<Atomic<EmulatorState>>,
     audio_on: Arc<[AtomicBool; 2]>,
+    watch_rom: Arc<[AtomicBool; 2]>,
     linked: Arc<AtomicBool>,
     profilers: [Option<ProfileSender>; 2],
     renderers: HashMap<SimId, TextureSink>,
@@ -165,6 +176,7 @@ impl Emulator {
         sim_state: Arc<[Atomic<SimState>; 2]>,
         state: Arc<Atomic<EmulatorState>>,
         audio_on: Arc<[AtomicBool; 2]>,
+        watch_rom: Arc<[AtomicBool; 2]>,
         linked: Arc<AtomicBool>,
     ) -> Result<Self> {
         Ok(Self {
@@ -175,6 +187,7 @@ impl Emulator {
             sim_state,
             state,
             audio_on,
+            watch_rom,
             linked,
             profilers: [None, None],
             renderers: HashMap::new(),
@@ -188,9 +201,18 @@ impl Emulator {
         })
     }
 
+    pub fn reload_cart(&mut self, sim_id: SimId) -> Result<()> {
+        let Some(cart) = &self.carts[sim_id.to_index()] else {
+            return Ok(());
+        };
+        let path = cart.file_path.clone();
+        self.load_cart(sim_id, &path)
+    }
+
     pub fn load_cart(&mut self, sim_id: SimId, path: &Path) -> Result<()> {
-        let cart = Cart::load(path, sim_id)?;
+        let watch = self.watch_rom[sim_id.to_index()].load(Ordering::Acquire);
-        self.reset_sim(sim_id, Some(cart))?;
+        let cart = Cart::load(path, sim_id, watch)?;
+        self.try_reset_sim(sim_id, Some(cart))?;
         Ok(())
     }
 
@@ -200,16 +222,26 @@ impl Emulator {
         } else {
             self.carts[0].as_ref().map(|c| c.file_path.clone())
         };
+        let watch = self.watch_rom[SimId::Player2.to_index()].load(Ordering::Acquire);
         let cart = match file_path {
-            Some(rom_path) => Some(Cart::load(&rom_path, SimId::Player2)?),
+            Some(rom_path) => Some(Cart::load(&rom_path, SimId::Player2, watch)?),
             None => None,
         };
-        self.reset_sim(SimId::Player2, cart)?;
+        self.try_reset_sim(SimId::Player2, cart)?;
         self.link_sims();
         Ok(())
     }
 
-    fn reset_sim(&mut self, sim_id: SimId, new_cart: Option<Cart>) -> Result<()> {
+    fn reset_sim(&mut self, sim_id: SimId, new_cart: Option<Cart>) -> bool {
+        if let Err(error) = self.try_reset_sim(sim_id, new_cart) {
+            self.report_error(sim_id, format!("Error resetting sim: {error}"));
+            false
+        } else {
+            true
+        }
+    }
+
+    fn try_reset_sim(&mut self, sim_id: SimId, new_cart: Option<Cart>) -> Result<()> {
         self.save_sram(sim_id)?;
 
         let index = sim_id.to_index();
@@ -230,6 +262,10 @@ impl Emulator {
             sim.load_cart(cart.rom.clone(), cart.sram.clone())?;
             self.carts[index] = Some(cart);
             self.sim_state[index].store(SimState::Ready, Ordering::Release);
+        } else if let Some(cart) = self.carts[index].as_mut()
+            && cart.is_watching()
+        {
+            cart.restart_watching();
         }
         let mut profiling = false;
         if let Some(profiler) = self.profilers[sim_id.to_index()].as_ref()
@@ -346,7 +382,7 @@ impl Emulator {
 
     fn start_profiling(&mut self, sim_id: SimId, sender: ProfileSender) -> Result<()> {
         self.profilers[sim_id.to_index()] = Some(sender);
-        self.reset_sim(sim_id, None)
+        self.try_reset_sim(sim_id, None)
     }
 
     fn start_debugging(&mut self, sim_id: SimId, sender: DebugSender) {
@@ -422,11 +458,30 @@ impl Emulator {
             let idle = self.tick();
             if idle {
                 // The game is paused, and we have output all the video/audio we have.
-                // Block the thread until a new command comes in.
+                // Block the thread until a new command comes in, or a ROM changes.
-                match self.commands.recv() {
+                loop {
-                    Ok(command) => self.handle_command(command),
+                    match self.commands.recv_timeout(Duration::from_millis(250)) {
-                    Err(RecvError) => {
+                        Ok(command) => {
-                        return;
+                            self.handle_command(command);
+                            break;
+                        }
+                        Err(RecvTimeoutError::Timeout) => {
+                            let mut changed = false;
+                            for sim_id in SimId::values() {
+                                let Some(cart) = self.carts[sim_id.to_index()].as_ref() else {
+                                    continue;
+                                };
+                                if cart.changed() {
+                                    changed |= self.reset_sim(sim_id, None);
+                                }
+                            }
+                            if changed {
+                                break;
+                            }
+                        }
+                        Err(RecvTimeoutError::Disconnected) => {
+                            return;
+                        }
                     }
                 }
             }
@@ -441,6 +496,14 @@ impl Emulator {
                     }
                 }
             }
+            for sim_id in SimId::values() {
+                let Some(cart) = self.carts[sim_id.to_index()].as_ref() else {
+                    continue;
+                };
+                if cart.changed() {
+                    self.reset_sim(sim_id, None);
+                }
+            }
             self.watched_regions.retain(|range, region| {
                 let Some(region) = region.upgrade() else {
                     return false;
@@ -607,6 +670,22 @@ impl Emulator {
                     self.report_error(sim_id, format!("Error loading rom: {error}"));
                 }
             }
+            EmulatorCommand::ReloadRom(sim_id) => {
+                if let Err(error) = self.reload_cart(sim_id) {
+                    self.report_error(sim_id, format!("Error loading rom: {error}"));
+                }
+            }
+            EmulatorCommand::WatchRom(sim_id, watch) => {
+                self.watch_rom[sim_id.to_index()].store(watch, Ordering::Release);
+                let Some(cart) = self.carts[sim_id.to_index()].as_mut() else {
+                    return;
+                };
+                if watch {
+                    cart.restart_watching();
+                } else {
+                    cart.stop_watching();
+                }
+            }
             EmulatorCommand::StartSecondSim(path) => {
                 if let Err(error) = self.start_second_sim(path) {
                     self.report_error(
@@ -730,9 +809,7 @@ impl Emulator {
                 self.unlink_sims();
             }
             EmulatorCommand::Reset(sim_id) => {
-                if let Err(error) = self.reset_sim(sim_id, None) {
+                self.reset_sim(sim_id, None);
-                    self.report_error(sim_id, format!("Error resetting sim: {error}"));
-                }
             }
             EmulatorCommand::SetKeys(sim_id, keys) => {
                 if let Some(sim) = self.sims.get_mut(sim_id.to_index()) {
@@ -774,6 +851,8 @@ impl Emulator {
 pub enum EmulatorCommand {
     ConnectToSim(SimId, TextureSink, mpsc::Sender<Toast>),
     LoadGame(SimId, PathBuf),
+    ReloadRom(SimId),
+    WatchRom(SimId, bool),
     StartSecondSim(Option<PathBuf>),
     StopSecondSim,
     Pause,
@@ -863,6 +942,7 @@ pub struct EmulatorClient {
     sim_state: Arc<[Atomic<SimState>; 2]>,
     state: Arc<Atomic<EmulatorState>>,
     linked: Arc<AtomicBool>,
+    watch_rom: Arc<[AtomicBool; 2]>,
 }
 
 impl EmulatorClient {
@@ -875,6 +955,9 @@ impl EmulatorClient {
     pub fn are_sims_linked(&self) -> bool {
         self.linked.load(Ordering::Acquire)
     }
+    pub fn is_rom_watched(&self, sim_id: SimId) -> bool {
+        self.watch_rom[sim_id.to_index()].load(Ordering::Acquire)
+    }
     pub fn send_command(&self, command: EmulatorCommand) -> bool {
         match self.queue.send(command) {
             Ok(()) => true,

src/emulator/cart.rs

@@ -1,10 +1,11 @@
 use anyhow::Result;
+use notify::Watcher;
 use rand::Rng;
 use std::{
     fs::{self, File},
     io::{Read, Seek as _, SeekFrom, Write as _},
     path::{Path, PathBuf},
-    sync::Arc,
+    sync::{Arc, atomic::AtomicBool},
 };
 
 use crate::emulator::{SimId, game_info::GameInfo, shrooms_vb_util::rom_from_isx};
@@ -15,10 +16,12 @@ pub struct Cart {
     sram_file: File,
     pub sram: Vec<u8>,
     pub info: Arc<GameInfo>,
+    watcher: Option<notify::RecommendedWatcher>,
+    changed: Arc<AtomicBool>,
 }
 
 impl Cart {
-    pub fn load(file_path: &Path, sim_id: SimId) -> Result<Self> {
+    pub fn load(file_path: &Path, sim_id: SimId, watch: bool) -> Result<Self> {
         let rom = fs::read(file_path)?;
         let (rom, info) = try_parse_isx(file_path, &rom)
             .or_else(|| try_parse_elf(file_path, &rom))
@@ -45,12 +48,21 @@ impl Cart {
             sram
         };
 
+        let changed = Arc::new(AtomicBool::new(false));
+        let watcher = if watch {
+            build_watcher(file_path, changed.clone())
+        } else {
+            None
+        };
+
         Ok(Cart {
             file_path: file_path.to_path_buf(),
             rom,
             sram_file,
             sram,
             info: Arc::new(info),
+            watcher,
+            changed,
         })
     }
 
@@ -59,6 +71,50 @@ impl Cart {
         self.sram_file.write_all(&self.sram)?;
         Ok(())
     }
+
+    pub fn changed(&self) -> bool {
+        self.changed.load(std::sync::atomic::Ordering::Relaxed)
+    }
+
+    pub fn is_watching(&self) -> bool {
+        self.watcher.is_some()
+    }
+
+    pub fn restart_watching(&mut self) {
+        self.changed = Arc::new(AtomicBool::new(false));
+        if let Some(mut watcher) = self.watcher.take() {
+            let _ = watcher.unwatch(&self.file_path);
+        };
+        self.watcher = build_watcher(&self.file_path, self.changed.clone());
+    }
+
+    pub fn stop_watching(&mut self) {
+        self.changed = Arc::new(AtomicBool::new(false));
+        self.watcher = None;
+    }
+}
+
+fn build_watcher(file_path: &Path, changed: Arc<AtomicBool>) -> Option<notify::RecommendedWatcher> {
+    let file_path = file_path.to_path_buf();
+    let mut watcher =
+        notify::recommended_watcher(move |event: Result<notify::Event, notify::Error>| {
+            let Ok(e) = event else {
+                return;
+            };
+            let modified = !matches!(
+                e.kind,
+                notify::EventKind::Access(_)
+                    | notify::EventKind::Modify(notify::event::ModifyKind::Metadata(_))
+            );
+            if modified {
+                changed.store(true, std::sync::atomic::Ordering::Relaxed);
+            }
+        })
+        .ok()?;
+    watcher
+        .watch(&file_path, notify::RecursiveMode::NonRecursive)
+        .ok()?;
+    Some(watcher)
 }
 
 fn try_parse_isx(file_path: &Path, data: &[u8]) -> Option<(Vec<u8>, GameInfo)> {

src/input.rs

@@ -460,6 +460,7 @@ struct PersistedGamepadMapping {
 #[derive(Clone, Copy, Serialize, Deserialize, PartialEq, Eq, Hash)]
 pub enum Command {
     OpenRom,
+    ReloadRom,
     Quit,
     FrameAdvance,
     FastForward(u32),
@@ -470,9 +471,10 @@ pub enum Command {
 }
 
 impl Command {
-    pub fn all() -> [Self; 7] {
+    pub fn all() -> [Self; 8] {
         [
             Self::OpenRom,
+            Self::ReloadRom,
             Self::Quit,
             Self::PauseResume,
             Self::Reset,
@@ -485,6 +487,7 @@ impl Command {
     pub fn name(self) -> &'static str {
         match self {
             Self::OpenRom => "Open ROM",
+            Self::ReloadRom => "Reload ROM",
             Self::Quit => "Exit",
             Self::PauseResume => "Pause/Resume",
             Self::Reset => "Reset",
@@ -516,6 +519,10 @@ impl Default for Shortcuts {
             Command::OpenRom,
             KeyboardShortcut::new(Modifiers::COMMAND, Key::O),
         );
+        shortcuts.set(
+            Command::ReloadRom,
+            KeyboardShortcut::new(Modifiers::COMMAND | Modifiers::SHIFT, Key::F5),
+        );
         shortcuts.set(
             Command::Quit,
             KeyboardShortcut::new(Modifiers::COMMAND, Key::Q),

src/main.rs

@@ -110,9 +110,14 @@ fn main() -> Result<()> {
     if args.profile {
         builder = builder.start_paused(true)
     }
-    let p1_audio_on = SimConfig::load(&persistence, SimId::Player1).audio_enabled;
+    let p1 = SimConfig::load(&persistence, SimId::Player1);
-    let p2_audio_on = SimConfig::load(&persistence, SimId::Player2).audio_enabled;
+    let p2 = SimConfig::load(&persistence, SimId::Player2);
-    builder = builder.with_audio_on(p1_audio_on, p2_audio_on);
+
+    let watch = args.watch;
+
+    builder = builder
+        .with_audio_on(p1.audio_enabled, p2.audio_enabled)
+        .with_watch_rom(watch, watch);
 
     ThreadBuilder::default()
         .name("Emulator".to_owned())

src/window/game.rs

@@ -85,6 +85,10 @@ impl GameWindow {
                             .send_command(EmulatorCommand::LoadGame(self.sim_id, path));
                     }
                 }
+                Command::ReloadRom => {
+                    self.client
+                        .send_command(EmulatorCommand::ReloadRom(self.sim_id));
+                }
                 Command::Quit => {
                     let _ = self.proxy.send_event(UserEvent::Quit(self.sim_id));
                 }
@@ -137,6 +141,18 @@ impl GameWindow {
                         .send_command(EmulatorCommand::LoadGame(self.sim_id, path));
                 }
             }
+            if ui
+                .add(self.button_for(ui.ctx(), "Reload ROM", Command::ReloadRom))
+                .clicked()
+            {
+                self.client
+                    .send_command(EmulatorCommand::ReloadRom(self.sim_id));
+            }
+            let watch_rom = self.client.is_rom_watched(self.sim_id);
+            if ui.selectable_button(watch_rom, "Watch ROM").clicked() {
+                self.client
+                    .send_command(EmulatorCommand::WatchRom(self.sim_id, !watch_rom));
+            }
             if ui
                 .add(self.button_for(ui.ctx(), "Quit", Command::Quit))
                 .clicked()