very early version of plugin system

src/server/plugins/backend_lua.rs

@@ -0,0 +1,38 @@
+use super::Backend;
+use mlua::prelude::*;
+
+pub struct BackendLua {
+    lua: Lua,
+}
+
+impl BackendLua {
+    pub fn new() -> Self {
+        let lua = Lua::new();
+
+        Self {
+            lua,
+        }
+    }
+}
+
+impl Backend for BackendLua {
+    fn load(&mut self, code: String) -> anyhow::Result<()> {
+        self.lua.load(code).exec().map_err(|e| { error!("[LUA] {:?}", e); e })?;
+        Ok(())
+    }
+
+    fn load_api(&mut self) -> anyhow::Result<()> {
+        let print_fn = self.lua.create_function(|_lua, (msg,): (String,)| {
+            info!("[LUA] {}", msg);
+            Ok(())
+        })?;
+
+        let api = self.lua.create_table()?;
+
+        api.set("print", print_fn)?;
+
+        self.lua.globals().set("MP", api)?;
+
+        Ok(())
+    }
+}

src/server/plugins/mod.rs

@@ -0,0 +1,51 @@
+pub mod backend_lua;
+
+use tokio::runtime::Runtime;
+use tokio::sync::mpsc::{self, Sender, Receiver};
+
+pub trait Backend {
+    fn load(&mut self, code: String) -> anyhow::Result<()>;
+    fn load_api(&mut self) -> anyhow::Result<()> { Ok(()) }
+}
+
+#[derive(Debug)]
+pub enum PluginBoundPluginEvent {
+
+}
+
+#[derive(Debug)]
+pub enum ServerBoundPluginEvent {
+    PluginLoaded,
+}
+
+pub struct Plugin {
+    runtime: Runtime,
+    tx: Sender<PluginBoundPluginEvent>,
+    rx: Receiver<ServerBoundPluginEvent>,
+}
+
+impl Plugin {
+    pub fn new(backend: Box<dyn Backend>) -> Self {
+        let runtime = Runtime::new().expect("Failed to create a tokio Runtime!");
+        let (pb_tx, mut pb_rx) = mpsc::channel(1_000);
+        let (sb_tx, sb_rx) = mpsc::channel(1_000);
+        runtime.spawn(async move {
+            if sb_tx.send(ServerBoundPluginEvent::PluginLoaded).await.is_err() {
+                error!("Plugin communication channels somehow already closed!");
+                return;
+            }
+            loop {
+                if let Some(message) = pb_rx.recv().await {
+                    debug!("Received message: {:?}", message);
+                } else {
+                    return;
+                }
+            }
+        });
+        Self {
+            runtime,
+            tx: pb_tx,
+            rx: sb_rx,
+        }
+    }
+}