Refactor to use dedicated thread for jvm

rust/src/events/join.rs

@@ -6,19 +6,19 @@ use pumpkin::{
 };
 use pumpkin_api_macros::with_runtime;
 use pumpkin_util::text::{TextComponent, color::NamedColor};
-use tokio::sync::Mutex;
+use tokio::sync::mpsc;
 
-use crate::plugin::manager::PluginManager;
+use crate::java::jvm::commands::JvmCommand;
 
 pub struct PatchBukkitJoinHandler {
-    pub plugin_manager: Arc<Mutex<PluginManager>>,
+    pub command_tx: mpsc::Sender<JvmCommand>,
 }
 
 #[with_runtime(global)]
 impl EventHandler<PlayerJoinEvent> for PatchBukkitJoinHandler {
     fn handle_blocking<'a>(
         &self,
-        server: &Arc<Server>,
+        _server: &Arc<Server>,
         event: &'a mut PlayerJoinEvent,
     ) -> BoxFuture<'a, ()> {
         Box::pin(async {

rust/src/events/mod.rs

@@ -1,16 +1,16 @@
 use std::sync::Arc;
 
 use pumpkin::plugin::{Context, EventPriority};
-use tokio::sync::Mutex;
+use tokio::sync::mpsc;
 
-use crate::{events::join::PatchBukkitJoinHandler, plugin::manager::PluginManager};
+use crate::{events::join::PatchBukkitJoinHandler, java::jvm::commands::JvmCommand};
 
 pub mod join;
 
-pub async fn register_handlers(plugin_manager: Arc<Mutex<PluginManager>>, server: &Arc<Context>) {
+pub async fn register_handlers(command_tx: mpsc::Sender<JvmCommand>, server: &Arc<Context>) {
     server
         .register_event(
-            Arc::new(PatchBukkitJoinHandler { plugin_manager }),
+            Arc::new(PatchBukkitJoinHandler { command_tx }),
             EventPriority::Highest,
             true,
         )

rust/src/java/jvm.rs

@@ -1,27 +0,0 @@
-use std::path::PathBuf;
-
-use j4rs::{InvocationArg, Jvm, JvmBuilder};
-
-pub fn initialize_jvm(j4rs_folder: &PathBuf) -> Result<Jvm, String> {
-    let jvm = JvmBuilder::new()
-        .with_base_path(j4rs_folder)
-        .build()
-        .map_err(|err| format!("JVM failed to init: {:?}", err))?;
-
-    Ok(jvm)
-}
-
-pub fn setup_patchbukkit_server(jvm: &Jvm) -> Result<(), String> {
-    let patchbukkit_server = jvm
-        .create_instance("org.patchbukkit.PatchBukkitServer", InvocationArg::empty())
-        .map_err(|err| format!("Failed to create PatchBukkitServer instance: {:?}", err))?;
-
-    jvm.invoke_static(
-        "org.bukkit.Bukkit",
-        "setServer",
-        &[InvocationArg::from(patchbukkit_server)],
-    )
-    .map_err(|err| format!("Failed to set Bukkit server: {:?}", err))?;
-
-    Ok(())
-}

rust/src/java/jvm/commands.rs

@@ -0,0 +1,41 @@
+use std::path::PathBuf;
+
+use anyhow::Result;
+use j4rs::Instance;
+use tokio::sync::oneshot;
+
+pub enum LoadPluginResult {
+    SuccessfullyLoadedSpigot,
+    SuccessfullyLoadedPaper,
+    FailedToLoadSpigotPlugin(anyhow::Error),
+    FailedToLoadPaperPlugin(anyhow::Error),
+    FailedToReadConfigurationFile(anyhow::Error),
+    NoConfigurationFile,
+}
+
+pub enum JvmCommand {
+    Initialize {
+        j4rs_path: PathBuf,
+        respond_to: oneshot::Sender<Result<()>>,
+    },
+    JavaCallback {
+        instance: Instance,
+        respond_to: oneshot::Sender<Result<()>>,
+    },
+    LoadPlugin {
+        plugin_path: PathBuf,
+        respond_to: oneshot::Sender<LoadPluginResult>,
+    },
+    InstantiateAllPlugins {
+        respond_to: oneshot::Sender<Result<()>>,
+    },
+    EnableAllPlugins {
+        respond_to: oneshot::Sender<Result<()>>,
+    },
+    DisableAllPlugins {
+        respond_to: oneshot::Sender<Result<()>>,
+    },
+    Shutdown {
+        respond_to: oneshot::Sender<Result<()>>,
+    },
+}

rust/src/java/jvm/mod.rs

@@ -0,0 +1,2 @@
+pub mod commands;
+pub mod worker;

rust/src/java/jvm/worker.rs

@@ -0,0 +1,244 @@
+use std::path::PathBuf;
+
+use anyhow::bail;
+use j4rs::{Instance, InvocationArg, Jvm, JvmBuilder};
+use tokio::sync::{mpsc, oneshot};
+
+use crate::{
+    java::{
+        jar::read_configs_from_jar,
+        jvm::commands::{JvmCommand, LoadPluginResult},
+    },
+    plugin::manager::PluginManager,
+};
+
+pub struct JvmWorker {
+    command_rx: mpsc::Receiver<JvmCommand>,
+    command_tx: mpsc::Sender<JvmCommand>,
+    pub plugin_manager: PluginManager,
+    jvm: Option<j4rs::Jvm>,
+}
+
+impl JvmWorker {
+    pub fn new(
+        command_tx: mpsc::Sender<JvmCommand>,
+        command_rx: mpsc::Receiver<JvmCommand>,
+    ) -> Self {
+        Self {
+            command_rx,
+            command_tx,
+            plugin_manager: PluginManager::new(),
+            jvm: None,
+        }
+    }
+
+    pub fn attach_thread(mut self) {
+        log::info!("JVM worker thread started");
+
+        while let Some(command) = self.command_rx.blocking_recv() {
+            match command {
+                JvmCommand::Initialize {
+                    j4rs_path,
+                    respond_to,
+                } => {
+                    let result = self.initialize_jvm(&j4rs_path);
+                    let _ = respond_to.send(result);
+                }
+                JvmCommand::JavaCallback {
+                    instance,
+                    respond_to,
+                } => {
+                    let result = self.process_java_callback(instance);
+                    let _ = respond_to.send(result);
+                }
+                JvmCommand::LoadPlugin {
+                    plugin_path,
+                    respond_to,
+                } => {
+                    let _ = match read_configs_from_jar(&plugin_path) {
+                        Ok(configs) => match configs {
+                            (Some(paper_plugin_config), spigot @ _) => {
+                                match self.plugin_manager.load_paper_plugin(
+                                    &plugin_path,
+                                    &paper_plugin_config,
+                                    &spigot,
+                                ) {
+                                    Ok(_) => {
+                                        respond_to.send(LoadPluginResult::SuccessfullyLoadedPaper)
+                                    }
+                                    Err(err) => respond_to
+                                        .send(LoadPluginResult::FailedToLoadPaperPlugin(err)),
+                                }
+                            }
+                            (None, Some(spigot)) => {
+                                match self
+                                    .plugin_manager
+                                    .load_spigot_plugin(&plugin_path, &spigot)
+                                {
+                                    Ok(_) => {
+                                        respond_to.send(LoadPluginResult::SuccessfullyLoadedSpigot)
+                                    }
+                                    Err(err) => respond_to
+                                        .send(LoadPluginResult::FailedToLoadSpigotPlugin(err)),
+                                }
+                            }
+                            (None, None) => respond_to.send(LoadPluginResult::NoConfigurationFile),
+                        },
+                        Err(err) => {
+                            respond_to.send(LoadPluginResult::FailedToReadConfigurationFile(err))
+                        }
+                    };
+                }
+                JvmCommand::InstantiateAllPlugins { respond_to } => {
+                    match self.jvm {
+                        Some(ref jvm) => {
+                            let _ =
+                                respond_to.send(self.plugin_manager.instantiate_all_plugins(jvm));
+                        }
+                        None => {
+                            unreachable!("Shouldn't be able to instantiate plugins without a JVM")
+                        }
+                    };
+                }
+                JvmCommand::EnableAllPlugins { respond_to } => {
+                    match self.jvm {
+                        Some(ref jvm) => {
+                            let _ = respond_to.send(self.plugin_manager.enable_all_plugins(jvm));
+                        }
+                        None => {
+                            unreachable!("Shouldn't be able to enable plugins without a JVM")
+                        }
+                    };
+                }
+                JvmCommand::DisableAllPlugins { respond_to } => {
+                    match self.jvm {
+                        Some(ref jvm) => {
+                            let _ = respond_to.send(self.plugin_manager.disable_all_plugins(jvm));
+                        }
+                        None => {
+                            unreachable!("Shouldn't be able to disable plugins without a JVM")
+                        }
+                    };
+                }
+                JvmCommand::Shutdown { respond_to } => {
+                    let _ = respond_to.send(self.plugin_manager.unload_all_plugins());
+                    break;
+                }
+            }
+        }
+
+        log::info!("JVM worker thread exited");
+    }
+
+    fn process_java_callback(&mut self, instance: Instance) -> anyhow::Result<()> {
+        let jvm = match self.jvm {
+            Some(ref jvm) => jvm,
+            None => bail!("JVM not initialized"),
+        };
+
+        let result = jvm.invoke(&instance, "getCallbackName", InvocationArg::empty())?;
+
+        let callback_name: String = jvm.to_rust(result)?;
+        match callback_name.as_str() {
+            "REGISTER_EVENT_CALLBACK" => {
+                let listener_name: String = jvm.to_rust(jvm.invoke(
+                    &instance,
+                    "getArg",
+                    &[&InvocationArg::try_from(0_i32)?],
+                )?)?;
+                let listener = jvm.cast(
+                    &jvm.invoke(&instance, "getArg", &[&InvocationArg::try_from(1_i32)?])?,
+                    "org.bukkit.event.Listener",
+                )?;
+                let plugin_instance = jvm.cast(
+                    &jvm.invoke(&instance, "getArg", &[&InvocationArg::try_from(2_i32)?])?,
+                    "org.bukkit.plugin.Plugin",
+                )?;
+                let plugin_name: String = jvm.to_rust(jvm.invoke(
+                    &plugin_instance,
+                    "getName",
+                    InvocationArg::empty(),
+                )?)?;
+
+                match self.plugin_manager.plugins.get_mut(&plugin_name) {
+                    Some(rust_plugin) => rust_plugin.listeners.insert(listener_name, listener),
+                    None => todo!(),
+                };
+            }
+            _ => log::warn!("Received unknown callback: {:?}", callback_name),
+        }
+
+        Ok(())
+    }
+
+    fn initialize_jvm(&mut self, j4rs_path: &PathBuf) -> anyhow::Result<()> {
+        log::info!("Initializing JVM with path: {:?}", j4rs_path);
+
+        let jvm = JvmBuilder::new().with_base_path(j4rs_path).build()?;
+
+        setup_patchbukkit_server(&jvm)?;
+
+        let callback_instance =
+            jvm.create_instance("org.patchbukkit.NativeCallbacks", InvocationArg::empty())?;
+
+        let callback_receiver = jvm.init_callback_channel(&callback_instance)?;
+
+        let command_tx = self.command_tx.clone();
+        std::thread::Builder::new()
+            .name("patchbukkit-jvm-callbacks".to_string())
+            .spawn(move || {
+                let thread_runtime = tokio::runtime::Builder::new_current_thread()
+                    .enable_all()
+                    .build()
+                    .unwrap();
+
+                thread_runtime.block_on(async {
+                    loop {
+                        match callback_receiver.rx().recv() {
+                            Ok(instance) => {
+                                let (sender, receiver) = oneshot::channel();
+                                if command_tx
+                                    .blocking_send(JvmCommand::JavaCallback {
+                                        instance,
+                                        respond_to: sender,
+                                    })
+                                    .is_err()
+                                {
+                                    log::info!(
+                                        "Command channel closed, stopping callback forwarder"
+                                    );
+                                    break;
+                                }
+
+                                if let Err(e) = receiver.await {
+                                    log::error!("Callback failed: {}", e);
+                                }
+                            }
+                            Err(e) => {
+                                log::error!("Java callback channel closed: {}", e);
+                                break;
+                            }
+                        }
+                    }
+                });
+            })?;
+
+        self.jvm = Some(jvm);
+
+        log::info!("JVM initialized successfully");
+        Ok(())
+    }
+}
+
+pub fn setup_patchbukkit_server(jvm: &Jvm) -> anyhow::Result<()> {
+    let patchbukkit_server =
+        jvm.create_instance("org.patchbukkit.PatchBukkitServer", InvocationArg::empty())?;
+
+    jvm.invoke_static(
+        "org.bukkit.Bukkit",
+        "setServer",
+        &[InvocationArg::from(patchbukkit_server)],
+    )?;
+
+    Ok(())
+}

rust/src/lib.rs

@@ -1,6 +1,5 @@
 use std::sync::Arc;
 
-use j4rs::{InvocationArg, Jvm};
 use pumpkin::plugin::Context;
 use pumpkin_api_macros::{plugin_impl, plugin_method};
 
@@ -13,162 +12,133 @@ pub mod plugin;
 use directories::setup_directories;
 use java::{
     jar::discover_jar_files,
-    jvm::{initialize_jvm, setup_patchbukkit_server},
     resources::{cleanup_stale_files, sync_embedded_resources},
 };
-use tokio::sync::Mutex;
+use tokio::sync::{mpsc, oneshot};
 
 use crate::{
-    events::register_handlers, java::jar::read_configs_from_jar, plugin::manager::PluginManager,
+    events::register_handlers,
+    java::jvm::{
+        commands::{JvmCommand, LoadPluginResult},
+        worker::JvmWorker,
+    },
 };
 
 async fn on_load_inner(plugin: &mut PatchBukkitPlugin, server: Arc<Context>) -> Result<(), String> {
     server.init_log();
     log::info!("Starting PatchBukkit");
 
-    register_handlers(plugin.plugin_manager.clone(), &server).await;
+    register_handlers(plugin.command_tx.clone(), &server).await;
 
     // Setup directories
     let dirs = setup_directories(&server)?;
 
     // Discover and prepare JAR files
     let jar_paths = discover_jar_files(&dirs.plugins);
-    for jar_path in &jar_paths {
-        match read_configs_from_jar(jar_path) {
-            Ok(configs) => match configs {
-                (Some(paper_plugin_config), spigot @ _) => {
-                    match plugin.plugin_manager.lock().await.load_paper_plugin(
-                        jar_path,
-                        &paper_plugin_config,
-                        &spigot,
-                    ) {
-                        Ok(_) => log::info!("Loaded Paper plugin from JAR: {}", jar_path.display()),
-                        Err(err) => log::error!("Failed to load Paper plugin from JAR: {}", err),
-                    }
-                }
-                (None, Some(spigot)) => {
-                    match plugin
-                        .plugin_manager
-                        .lock()
-                        .await
-                        .load_spigot_plugin(jar_path, &spigot)
+    for jar_path in jar_paths {
         {
-                        Ok(_) => {
-                            log::info!("Loaded Spigot plugin from JAR: {}", jar_path.display())
-                        }
-                        Err(err) => log::error!("Failed to load Spigot plugin from JAR: {}", err),
-                    }
-                }
-                (None, None) => log::warn!(
-                    "Could not find any plugin configuration in JAR: {}",
-                    jar_path.display()
-                ),
-            },
-            Err(err) => {
+            let (tx, rx) = oneshot::channel();
+            let result = plugin
+                .command_tx
+                .send(JvmCommand::LoadPlugin {
+                    plugin_path: jar_path.clone(),
+                    respond_to: tx,
+                })
+                .await;
+            if let Err(e) = result {
                 log::error!(
-                    "Failed to read configs from PatchBukkit plugin jar: {}",
-                    err
+                    "Failed to send command to load plugin {}: {}",
+                    jar_path.display(),
+                    e
                 );
             }
+            match rx.await {
+                Ok(result) => match result {
+                    LoadPluginResult::SuccessfullyLoadedSpigot => {
+                        log::info!("Loaded Spigot plugin from JAR `{}`", jar_path.display())
                     }
+                    LoadPluginResult::SuccessfullyLoadedPaper => {
+                        log::info!("Loaded Paper plugin from JAR `{}`", jar_path.display())
+                    }
+                    LoadPluginResult::FailedToLoadSpigotPlugin(error) => {
+                        log::error!(
+                            "Failed to load Spigot plugin from JAR `{}` with error: {}",
+                            jar_path.display(),
+                            error
+                        )
+                    }
+                    LoadPluginResult::FailedToLoadPaperPlugin(error) => {
+                        log::error!(
+                            "Failed to load Paper plugin from JAR `{}` with error: {}",
+                            jar_path.display(),
+                            error
+                        )
+                    }
+                    LoadPluginResult::FailedToReadConfigurationFile(error) => {
+                        log::error!(
+                            "Failed to read configuration file from JAR `{}`: {}",
+                            jar_path.display(),
+                            error
+                        )
+                    }
+                    LoadPluginResult::NoConfigurationFile => {
+                        log::warn!(
+                            "No configuration file found for plugin from JAR `{}`",
+                            jar_path.display()
+                        )
+                    }
+                },
+                Err(e) => log::error!(
+                    "Failed to receive load plugin response for JAR `{}`: {}",
+                    jar_path.display(),
+                    e
+                ),
+            }
+        };
     }
 
     // Manage embedded resources
     cleanup_stale_files(&dirs.j4rs);
     sync_embedded_resources(&dirs.j4rs)?;
 
-    // Initialize JVM and PatchBukkit server
-    let jvm = initialize_jvm(&dirs.j4rs)?;
-    setup_patchbukkit_server(&jvm)?;
-
-    let i = jvm
-        .create_instance("org.patchbukkit.NativeCallbacks", InvocationArg::empty())
-        .map_err(|err| err.to_string())?;
-    let r = jvm.init_callback_channel(&i).unwrap();
-
-    let plugin_manager = plugin.plugin_manager.clone();
-    tokio::spawn(async move {
-        loop {
-            match r.rx().recv() {
-                Ok(ret) => {
-                    let result: anyhow::Result<()> = (async || {
-                        let jvm = match Jvm::attach_thread() {
-                            Ok(jvm) => jvm,
-                            Err(e) => {
-                                log::error!("Failed to attach callback thread to JVM: {}", e);
-                                return Ok(());
-                            }
-                        };
-
-                        let result = jvm.invoke(&ret, "getCallbackName", InvocationArg::empty())?;
-
-                        let callback_name: String = jvm.to_rust(result)?;
-                        match callback_name.as_str() {
-                            "REGISTER_EVENT_CALLBACK" => {
-                                let listener_name: String = jvm.to_rust(jvm.invoke(
-                                    &ret,
-                                    "getArg",
-                                    &[&InvocationArg::try_from(0_i32)?],
-                                )?)?;
-                                let listener = jvm.cast(
-                                    &jvm.invoke(
-                                        &ret,
-                                        "getArg",
-                                        &[&InvocationArg::try_from(1_i32)?],
-                                    )?,
-                                    "org.bukkit.event.Listener",
-                                )?;
-                                let plugin_instance = jvm.cast(
-                                    &jvm.invoke(
-                                        &ret,
-                                        "getArg",
-                                        &[&InvocationArg::try_from(2_i32)?],
-                                    )?,
-                                    "org.bukkit.plugin.Plugin",
-                                )?;
-                                let plugin_name: String = jvm.to_rust(jvm.invoke(
-                                    &plugin_instance,
-                                    "getName",
-                                    InvocationArg::empty(),
-                                )?)?;
-
-                                match plugin_manager.lock().await.plugins.get_mut(&plugin_name) {
-                                    Some(rust_plugin) => {
-                                        rust_plugin.listeners.insert(listener_name, listener)
-                                    }
-                                    None => todo!(),
-                                };
-                            }
-                            _ => log::warn!("Received unknown callback: {:?}", callback_name),
-                        }
-
-                        return Ok(());
-                    })()
-                    .await;
-
-                    result.unwrap();
-                }
-                Err(e) => {
-                    log::error!("Callback channel closed: {}", e);
-                    break;
-                }
-            }
-        }
-    });
-
+    {
+        let (tx, rx) = oneshot::channel();
         plugin
-        .plugin_manager
-        .lock()
+            .command_tx
+            .send(JvmCommand::Initialize {
+                j4rs_path: dirs.j4rs,
+                respond_to: tx,
+            })
             .await
-        .load_all_plugins(&jvm)
-        .map_err(|err| format!("Failed to load PatchBukkit plugins: {}", err))?;
+            .map_err(|e| format!("Failed to send command to initialize J4RS: {}", e))?;
+        rx.await
+            .map_err(|e| format!("Unable to receive response from J4RS initialization: {}", e))?
+            .map_err(|e| format!("Failed to initialize all plugins: {}", e))?;
+    }
 
+    {
+        let (tx, rx) = oneshot::channel();
         plugin
-        .plugin_manager
-        .lock()
+            .command_tx
+            .send(JvmCommand::InstantiateAllPlugins { respond_to: tx })
             .await
-        .enable_all_plugins(&jvm)
-        .map_err(|err| format!("Failed to enable PatchBukkit plugins: {}", err))?;
+            .map_err(|e| format!("Failed to send command to instantiate plugins: {}", e))?;
+        rx.await
+            .map_err(|e| format!("Unable to receive response from instantiate plugins: {}", e))?
+            .map_err(|e| format!("Failed to instantiate all plugins: {}", e))?;
+    }
+
+    {
+        let (tx, rx) = oneshot::channel();
+        plugin
+            .command_tx
+            .send(JvmCommand::EnableAllPlugins { respond_to: tx })
+            .await
+            .map_err(|e| format!("Failed to send command to enable all plugins: {}", e))?;
+        rx.await
+            .map_err(|e| format!("Unable to receive response from enable all plugins: {}", e))?
+            .map_err(|e| format!("Failed to enable all plugins: {}", e))?;
+    };
 
     Ok(())
 }
@@ -177,21 +147,29 @@ async fn on_unload_inner(
     plugin: &mut PatchBukkitPlugin,
     _server: Arc<Context>,
 ) -> Result<(), String> {
-    let jvm = Jvm::attach_thread().map_err(|e| format!("Failed to attach thread to JVM: {}", e))?;
-
+    {
+        let (tx, rx) = oneshot::channel();
         plugin
-        .plugin_manager
-        .lock()
+            .command_tx
+            .send(JvmCommand::DisableAllPlugins { respond_to: tx })
             .await
-        .disable_all_plugins(&jvm)
-        .map_err(|err| format!("Failed to disable PatchBukkit plugins: {}", err))?;
+            .map_err(|e| format!("Failed to send command to disable all plugins: {}", e))?;
+        rx.await
+            .map_err(|e| format!("Unable to receive response from disable all plugins: {}", e))?
+            .map_err(|e| format!("Failed to disable all plugins: {}", e))?;
+    }
 
+    {
+        let (tx, rx) = oneshot::channel();
         plugin
-        .plugin_manager
-        .lock()
+            .command_tx
+            .send(JvmCommand::Shutdown { respond_to: tx })
             .await
-        .unload_all_plugins()
-        .map_err(|err| format!("Failed to unload PatchBukkit plugins: {}", err))?;
+            .map_err(|e| format!("Failed to send command to shutdown: {}", e))?;
+        rx.await
+            .map_err(|e| format!("Unable to receive response from shutdown: {}", e))?
+            .map_err(|e| format!("Failed to shutdown: {}", e))?;
+    }
 
     Ok(())
 }
@@ -208,14 +186,20 @@ async fn on_unload(&mut self, server: Arc<Context>) -> Result<(), String> {
 
 #[plugin_impl]
 pub struct PatchBukkitPlugin {
-    plugin_manager: Arc<Mutex<PluginManager>>,
+    pub command_tx: mpsc::Sender<JvmCommand>,
 }
 
 impl PatchBukkitPlugin {
     pub fn new() -> Self {
-        PatchBukkitPlugin {
-            plugin_manager: Arc::new(Mutex::new(PluginManager::new())),
-        }
+        let (tx, rx) = mpsc::channel(100);
+        let command_tx = tx.clone();
+        std::thread::Builder::new()
+            .name("patchbukkit-jvm-worker".to_string())
+            .spawn(move || {
+                JvmWorker::new(command_tx.clone(), rx).attach_thread();
+            })
+            .unwrap();
+        PatchBukkitPlugin { command_tx: tx }
     }
 }
 

rust/src/plugin/manager.rs

@@ -181,7 +181,7 @@ impl PluginManager {
         Ok(())
     }
 
-    pub fn load_all_plugins(&mut self, jvm: &Jvm) -> Result<()> {
+    pub fn instantiate_all_plugins(&mut self, jvm: &Jvm) -> Result<()> {
         for (_plugin_name, plugin) in &mut self.plugins {
             let result = jvm.invoke_static(
                 "org.patchbukkit.loader.PatchBukkitPluginLoader",