From 2fe82be3bcb326af04c4c862431237c576ed1152 Mon Sep 17 00:00:00 2001
From: Alex Auvolat <alex@adnab.me>
Date: Thu, 23 Apr 2020 14:40:59 +0000
Subject: RPC to ourself do not pass through serialization + HTTPS

---
 src/rpc_client.rs | 45 ++++++++++++++++++++++++++++++++++++---------
 1 file changed, 36 insertions(+), 9 deletions(-)

(limited to 'src/rpc_client.rs')

diff --git a/src/rpc_client.rs b/src/rpc_client.rs
index 8bc3fe50..e78079c2 100644
--- a/src/rpc_client.rs
+++ b/src/rpc_client.rs
@@ -1,10 +1,13 @@
 use std::borrow::Borrow;
 use std::marker::PhantomData;
 use std::net::SocketAddr;
+use std::pin::Pin;
 use std::sync::Arc;
 use std::time::Duration;
 
+use arc_swap::ArcSwapOption;
 use bytes::IntoBuf;
+use futures::future::Future;
 use futures::stream::futures_unordered::FuturesUnordered;
 use futures::stream::StreamExt;
 use futures_util::future::FutureExt;
@@ -47,10 +50,15 @@ impl RequestStrategy {
 	}
 }
 
+pub type LocalHandlerFn<M> =
+	Box<dyn Fn(Arc<M>) -> Pin<Box<dyn Future<Output = Result<M, Error>> + Send>> + Send + Sync>;
+
 pub struct RpcClient<M: RpcMessage> {
 	status: watch::Receiver<Arc<Status>>,
 	background: Arc<BackgroundRunner>,
 
+	local_handler: ArcSwapOption<(UUID, LocalHandlerFn<M>)>,
+
 	pub rpc_addr_client: RpcAddrClient<M>,
 }
 
@@ -64,19 +72,38 @@ impl<M: RpcMessage + 'static> RpcClient<M> {
 			rpc_addr_client: rac,
 			background,
 			status,
+			local_handler: ArcSwapOption::new(None),
 		})
 	}
 
+	pub fn set_local_handler<F, Fut>(&self, my_id: UUID, handler: F)
+	where
+		F: Fn(Arc<M>) -> Fut + Send + Sync + 'static,
+		Fut: Future<Output = Result<M, Error>> + Send + 'static,
+	{
+		let handler_arc = Arc::new(handler);
+		let handler: LocalHandlerFn<M> = Box::new(move |msg| {
+			let handler_arc2 = handler_arc.clone();
+			Box::pin(async move { handler_arc2(msg).await })
+		});
+		self.local_handler.swap(Some(Arc::new((my_id, handler))));
+	}
+
 	pub fn by_addr(&self) -> &RpcAddrClient<M> {
 		&self.rpc_addr_client
 	}
 
-	pub async fn call<MB: Borrow<M>, N: Borrow<UUID>>(
-		&self,
-		to: N,
-		msg: MB,
-		timeout: Duration,
-	) -> Result<M, Error> {
+	pub async fn call(&self, to: UUID, msg: M, timeout: Duration) -> Result<M, Error> {
+		self.call_arc(to, Arc::new(msg), timeout).await
+	}
+
+	pub async fn call_arc(&self, to: UUID, msg: Arc<M>, timeout: Duration) -> Result<M, Error> {
+		if let Some(lh) = self.local_handler.load_full() {
+			let (my_id, local_handler) = lh.as_ref();
+			if to.borrow() == my_id {
+				return local_handler(msg).await;
+			}
+		}
 		let addr = {
 			let status = self.status.borrow().clone();
 			match status.nodes.get(to.borrow()) {
@@ -96,7 +123,7 @@ impl<M: RpcMessage + 'static> RpcClient<M> {
 		let msg = Arc::new(msg);
 		let mut resp_stream = to
 			.iter()
-			.map(|to| self.call(to, msg.clone(), timeout))
+			.map(|to| self.call_arc(*to, msg.clone(), timeout))
 			.collect::<FuturesUnordered<_>>();
 
 		let mut results = vec![];
@@ -121,7 +148,7 @@ impl<M: RpcMessage + 'static> RpcClient<M> {
 			.map(|to| {
 				let self2 = self.clone();
 				let msg = msg.clone();
-				async move { self2.call(to, msg, timeout).await }
+				async move { self2.call_arc(to, msg, timeout).await }
 			})
 			.collect::<FuturesUnordered<_>>();
 
@@ -155,7 +182,7 @@ impl<M: RpcMessage + 'static> RpcClient<M> {
 					resp_stream.collect::<Vec<_>>().await;
 					Ok(())
 				});
-				self.clone().background.spawn(wait_finished_fut.map(|x| {
+				self.background.spawn(wait_finished_fut.map(|x| {
 					x.unwrap_or_else(|e| Err(Error::Message(format!("Await failed: {}", e))))
 				}));
 			}
-- 
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