make eval copy

packages/liveview/src/eval.rs

@@ -1,9 +1,7 @@
-#![allow(clippy::await_holding_refcell_ref)]
-
-use async_trait::async_trait;
 use dioxus_core::ScopeId;
 use dioxus_html::prelude::{EvalError, EvalProvider, Evaluator};
-use std::{cell::RefCell, rc::Rc};
+use generational_box::{AnyStorage, GenerationalBox, UnsyncStorage};
+use std::rc::Rc;
 
 use crate::query::{Query, QueryEngine};
 
@@ -14,48 +12,51 @@ pub fn init_eval() {
     ScopeId::ROOT.provide_context(provider);
 }
 
-/// Reprents the desktop-target's provider of evaluators.
+/// Reprints the desktop-target's provider of evaluators.
 pub struct DesktopEvalProvider {
     query: QueryEngine,
 }
 
 impl EvalProvider for DesktopEvalProvider {
-    fn new_evaluator(&self, js: String) -> Result<Box<dyn Evaluator>, EvalError> {
-        Ok(Box::new(DesktopEvaluator::new(self.query.clone(), js)))
+    fn new_evaluator(&self, js: String) -> Result<GenerationalBox<Box<dyn Evaluator>>, EvalError> {
+        Ok(DesktopEvaluator::create(self.query.clone(), js))
     }
 }
 
 /// Reprents a desktop-target's JavaScript evaluator.
 pub(crate) struct DesktopEvaluator {
-    query: Rc<RefCell<Query<serde_json::Value>>>,
+    query: Query<serde_json::Value>,
 }
 
 impl DesktopEvaluator {
     /// Creates a new evaluator for desktop-based targets.
-    pub fn new(query: QueryEngine, js: String) -> Self {
-        let query = query.new_query(&js);
+    pub fn create(query_engine: QueryEngine, js: String) -> GenerationalBox<Box<dyn Evaluator>> {
+        let query = query_engine.new_query(&js);
+        // We create a generational box that is owned by the query slot so that when we drop the query slot, the generational box is also dropped.
+        let owner = UnsyncStorage::owner();
+        let query_id = query.id;
+        let query = owner.insert(Box::new(DesktopEvaluator { query }) as Box<dyn Evaluator>);
+        query_engine.active_requests.slab.borrow_mut()[query_id].owner = Some(owner);
 
-        Self {
-            query: Rc::new(RefCell::new(query)),
-        }
+        query
     }
 }
 
-#[async_trait(?Send)]
 impl Evaluator for DesktopEvaluator {
     /// # Panics
     /// This will panic if the query is currently being awaited.
-    async fn join(&self) -> Result<serde_json::Value, EvalError> {
+    fn poll_join(
+        &mut self,
+        context: &mut std::task::Context<'_>,
+    ) -> std::task::Poll<Result<serde_json::Value, EvalError>> {
         self.query
-            .borrow_mut()
-            .result()
-            .await
+            .poll_result(context)
             .map_err(|e| EvalError::Communication(e.to_string()))
     }
 
     /// Sends a message to the evaluated JavaScript.
     fn send(&self, data: serde_json::Value) -> Result<(), EvalError> {
-        if let Err(e) = self.query.borrow_mut().send(data) {
+        if let Err(e) = self.query.send(data) {
             return Err(EvalError::Communication(e.to_string()));
         }
         Ok(())
@@ -65,11 +66,12 @@ impl Evaluator for DesktopEvaluator {
     ///
     /// # Panics
     /// This will panic if the query is currently being awaited.
-    async fn recv(&mut self) -> Result<serde_json::Value, EvalError> {
+    fn poll_recv(
+        &mut self,
+        context: &mut std::task::Context<'_>,
+    ) -> std::task::Poll<Result<serde_json::Value, EvalError>> {
         self.query
-            .borrow_mut()
-            .recv()
-            .await
+            .poll_recv(context)
             .map_err(|e| EvalError::Communication(e.to_string()))
     }
 }

packages/liveview/src/query.rs

@@ -1,5 +1,7 @@
 use std::{cell::RefCell, rc::Rc};
 
+use futures_util::FutureExt;
+use generational_box::{Owner, UnsyncStorage};
 use serde::{de::DeserializeOwned, Deserialize};
 use serde_json::Value;
 use slab::Slab;
@@ -42,8 +44,8 @@ let dioxus = {
 
 /// Tracks what query ids are currently active
 
-struct SharedSlab<T = ()> {
-    slab: Rc<RefCell<Slab<T>>>,
+pub(crate) struct SharedSlab<T = ()> {
+    pub(crate) slab: Rc<RefCell<Slab<T>>>,
 }
 
 impl<T> Clone for SharedSlab<T> {
@@ -62,9 +64,10 @@ impl<T> Default for SharedSlab<T> {
     }
 }
 
-struct QueryEntry {
+pub(crate) struct QueryEntry {
     channel_sender: tokio::sync::mpsc::UnboundedSender<Value>,
     return_sender: Option<tokio::sync::oneshot::Sender<Value>>,
+    pub(crate) owner: Option<Owner<UnsyncStorage>>,
 }
 
 const QUEUE_NAME: &str = "__msg_queues";
@@ -72,7 +75,7 @@ const QUEUE_NAME: &str = "__msg_queues";
 /// Handles sending and receiving arbitrary queries from the webview. Queries can be resolved non-sequentially, so we use ids to track them.
 #[derive(Clone)]
 pub(crate) struct QueryEngine {
-    active_requests: SharedSlab<QueryEntry>,
+    pub(crate) active_requests: SharedSlab<QueryEntry>,
     query_tx: tokio::sync::mpsc::UnboundedSender<String>,
 }
 
@@ -91,6 +94,7 @@ impl QueryEngine {
         let request_id = self.active_requests.slab.borrow_mut().insert(QueryEntry {
             channel_sender: tx,
             return_sender: Some(return_tx),
+            owner: None,
         });
 
         // start the query
@@ -162,7 +166,7 @@ pub(crate) struct Query<V: DeserializeOwned> {
     query_engine: QueryEngine,
     pub receiver: tokio::sync::mpsc::UnboundedReceiver<Value>,
     pub return_receiver: Option<tokio::sync::oneshot::Receiver<Value>>,
-    id: usize,
+    pub id: usize,
     phantom: std::marker::PhantomData<V>,
 }
 
@@ -198,12 +202,14 @@ impl<V: DeserializeOwned> Query<V> {
         Ok(())
     }
 
-    /// Receive a message from the query
-    pub async fn recv(&mut self) -> Result<Value, QueryError> {
+    /// Poll the query for a message
+    pub fn poll_recv(
+        &mut self,
+        cx: &mut std::task::Context<'_>,
+    ) -> std::task::Poll<Result<Value, QueryError>> {
         self.receiver
-            .recv()
-            .await
-            .ok_or(QueryError::Recv(RecvError::Closed))
+            .poll_recv(cx)
+            .map(|result| result.ok_or(QueryError::Recv(RecvError::Closed)))
     }
 
     /// Receive the result of the query
@@ -215,6 +221,19 @@ impl<V: DeserializeOwned> Query<V> {
             None => Err(QueryError::Finished),
         }
     }
+
+    /// Poll the query for a result
+    pub fn poll_result(
+        &mut self,
+        cx: &mut std::task::Context<'_>,
+    ) -> std::task::Poll<Result<Value, QueryError>> {
+        match self.return_receiver.as_mut() {
+            Some(receiver) => receiver
+                .poll_unpin(cx)
+                .map_err(|_| QueryError::Recv(RecvError::Closed)),
+            None => std::task::Poll::Ready(Err(QueryError::Finished)),
+        }
+    }
 }
 
 impl<V: DeserializeOwned> Drop for Query<V> {