Prelude/Main: rework hook system

youmubot-osu/src/discord/hook.rs

@@ -25,7 +25,11 @@ lazy_static! {
     ).unwrap();
 }
 
-pub async fn hook(ctx: &Context, msg: &Message) -> Result<()> {
+pub fn hook<'a>(
+    ctx: &'a Context,
+    msg: &'a Message,
+) -> std::pin::Pin<Box<dyn future::Future<Output = Result<()>> + Send + 'a>> {
+    Box::pin(async move {
         if msg.author.bot {
             return Ok(());
         }
@@ -68,6 +72,7 @@ pub async fn hook(ctx: &Context, msg: &Message) -> Result<()> {
             super::cache::save_beatmap(&*ctx.data.read().await, msg.channel_id, &t)?;
         }
         Ok(())
+    })
 }
 
 enum EmbedType {

youmubot-osu/src/discord/mod.rs

@@ -49,7 +49,7 @@ impl TypeMapKey for OsuClient {
 ///  - Commands on the "osu" prefix
 ///  - Hooks. Hooks are completely opt-in.
 ///  
-pub async fn setup(
+pub fn setup(
     path: &std::path::Path,
     data: &mut TypeMap,
     announcers: &mut AnnouncerHandler,

youmubot-prelude/src/hook.rs

@@ -0,0 +1,24 @@
+use crate::{async_trait, future, Context, Result};
+use serenity::model::channel::Message;
+
+/// Hook represents the asynchronous hook that is run on every message.
+#[async_trait]
+pub trait Hook: Send + Sync {
+    async fn call(&mut self, ctx: &Context, message: &Message) -> Result<()>;
+}
+
+#[async_trait]
+impl<T> Hook for T
+where
+    T: for<'a> FnMut(
+            &'a Context,
+            &'a Message,
+        )
+            -> std::pin::Pin<Box<dyn future::Future<Output = Result<()>> + 'a + Send>>
+        + Send
+        + Sync,
+{
+    async fn call(&mut self, ctx: &Context, message: &Message) -> Result<()> {
+        self(ctx, message).await
+    }
+}

youmubot-prelude/src/lib.rs

@@ -5,11 +5,13 @@ use std::sync::Arc;
 
 pub mod announcer;
 pub mod args;
+pub mod hook;
 pub mod pagination;
 pub mod setup;
 
 pub use announcer::{Announcer, AnnouncerHandler};
 pub use args::{Duration, UsernameArg};
+pub use hook::Hook;
 pub use pagination::paginate;
 
 /// Re-exporting async_trait helps with implementing Announcer.

youmubot/src/main.rs

@@ -13,13 +13,17 @@ use serenity::{
 use youmubot_prelude::*;
 
 struct Handler {
-    hooks: Vec<fn(&mut Context, &Message) -> ()>,
+    hooks: Vec<RwLock<Box<dyn Hook>>>,
 }
 
 impl Handler {
     fn new() -> Handler {
         Handler { hooks: vec![] }
     }
+
+    fn push_hook<T: Hook + 'static>(&mut self, f: T) {
+        self.hooks.push(RwLock::new(Box::new(f)));
+    }
 }
 
 #[async_trait]
@@ -28,8 +32,22 @@ impl EventHandler for Handler {
         println!("{} is connected!", ready.user.name);
     }
 
-    async fn message(&self, mut ctx: Context, message: Message) {
+    async fn message(&self, ctx: Context, message: Message) {
-        self.hooks.iter().for_each(|f| f(&mut ctx, &message));
+        self.hooks
+            .iter()
+            .map(|hook| {
+                let ctx = ctx.clone();
+                let message = message.clone();
+                hook.write()
+                    .then(|mut h| async move { h.call(&ctx, &message).await })
+            })
+            .collect::<stream::FuturesUnordered<_>>()
+            .for_each(|v| async move {
+                if let Err(e) = v {
+                    eprintln!("{}", e)
+                }
+            })
+            .await;
     }
 }
 
@@ -53,12 +71,12 @@ async fn main() {
         println!("Loaded dotenv from {:?}", path);
     }
 
-    let handler = Handler::new();
+    let mut handler = Handler::new();
     // Set up hooks
     #[cfg(feature = "osu")]
-    handler.hooks.push(youmubot_osu::discord::hook);
+    handler.push_hook(youmubot_osu::discord::hook);
     #[cfg(feature = "codeforces")]
-    handler.hooks.push(youmubot_cf::codeforces_info_hook);
+    handler.push_hook(youmubot_cf::codeforces_info_hook);
 
     // Collect the token
     let token = var("TOKEN").expect("Please set TOKEN as the Discord Bot's token to be used.");