switch to a Document trait and introduce Script/Head/Style/Meta components (#2635)

* switch to a Document trait and introduce Script/Head/Style/Meta components

* Fix desktop title

* Insert special elements into the head during the inital SSR render

* Make all head component attributes optional

* hydrate head elements

* improve the server streaming head warning

* Document fullstack head hydration approach

* deduplicate head elements by href

* move Link into head::Link

* document head components

* add meta and title examples

* Fix a few doc examples

* fix formatting

* Add title to playwright tests

* serde is optional on web, but it is enabled by hydrate

* remove leftover console log

packages/desktop/src/document.rs

@@ -0,0 +1,75 @@
+use dioxus_html::document::{Document, EvalError, Evaluator};
+use generational_box::{AnyStorage, GenerationalBox, UnsyncStorage};
+
+use crate::{query::Query, DesktopContext};
+
+/// Represents the desktop-target's provider of evaluators.
+pub struct DesktopDocument {
+    pub(crate) desktop_ctx: DesktopContext,
+}
+
+impl DesktopDocument {
+    pub fn new(desktop_ctx: DesktopContext) -> Self {
+        Self { desktop_ctx }
+    }
+}
+
+impl Document for DesktopDocument {
+    fn new_evaluator(&self, js: String) -> GenerationalBox<Box<dyn Evaluator>> {
+        DesktopEvaluator::create(self.desktop_ctx.clone(), js)
+    }
+
+    fn set_title(&self, title: String) {
+        self.desktop_ctx.window.set_title(&title);
+    }
+}
+
+/// Represents a desktop-target's JavaScript evaluator.
+pub(crate) struct DesktopEvaluator {
+    query: Query<serde_json::Value>,
+}
+
+impl DesktopEvaluator {
+    /// Creates a new evaluator for desktop-based targets.
+    pub fn create(desktop_ctx: DesktopContext, js: String) -> GenerationalBox<Box<dyn Evaluator>> {
+        let ctx = desktop_ctx.clone();
+        let query = desktop_ctx.query.new_query(&js, ctx);
+
+        // 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>);
+        desktop_ctx.query.active_requests.slab.borrow_mut()[query_id].owner = Some(owner);
+
+        query
+    }
+}
+
+impl Evaluator for DesktopEvaluator {
+    fn poll_join(
+        &mut self,
+        cx: &mut std::task::Context<'_>,
+    ) -> std::task::Poll<Result<serde_json::Value, EvalError>> {
+        self.query
+            .poll_result(cx)
+            .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.send(data) {
+            return Err(EvalError::Communication(e.to_string()));
+        }
+        Ok(())
+    }
+
+    /// Gets an UnboundedReceiver to receive messages from the evaluated JavaScript.
+    fn poll_recv(
+        &mut self,
+        cx: &mut std::task::Context<'_>,
+    ) -> std::task::Poll<Result<serde_json::Value, EvalError>> {
+        self.query
+            .poll_recv(cx)
+            .map_err(|e| EvalError::Communication(e.to_string()))
+    }
+}