More cleanup work

packages/desktop/src/assets.rs

@@ -0,0 +1,138 @@
+use crate::edits::EditQueue;
+use crate::DesktopContext;
+use dioxus_core::ScopeState;
+use slab::Slab;
+use std::{
+    borrow::Cow,
+    future::Future,
+    ops::Deref,
+    path::{Path, PathBuf},
+    pin::Pin,
+    rc::Rc,
+    sync::Arc,
+};
+use tokio::{
+    runtime::Handle,
+    sync::{OnceCell, RwLock},
+};
+use wry::{
+    http::{status::StatusCode, Request, Response},
+    Result,
+};
+
+/// An arbitrary asset is an HTTP response containing a binary body.
+pub type AssetResponse = Response<Cow<'static, [u8]>>;
+
+/// A future that returns an [`AssetResponse`]. This future may be spawned in a new thread,
+/// so it must be [`Send`], [`Sync`], and `'static`.
+pub trait AssetFuture: Future<Output = Option<AssetResponse>> + Send + Sync + 'static {}
+impl<T: Future<Output = Option<AssetResponse>> + Send + Sync + 'static> AssetFuture for T {}
+
+#[derive(Debug, Clone)]
+/// A request for an asset. This is a wrapper around [`Request<Vec<u8>>`] that provides methods specific to asset requests.
+pub struct AssetRequest {
+    pub(crate) path: PathBuf,
+    pub(crate) request: Arc<Request<Vec<u8>>>,
+}
+
+impl AssetRequest {
+    /// Get the path the asset request is for
+    pub fn path(&self) -> &Path {
+        &self.path
+    }
+}
+
+impl From<Request<Vec<u8>>> for AssetRequest {
+    fn from(request: Request<Vec<u8>>) -> Self {
+        let decoded = urlencoding::decode(request.uri().path().trim_start_matches('/'))
+            .expect("expected URL to be UTF-8 encoded");
+        let path = PathBuf::from(&*decoded);
+        Self {
+            request: Arc::new(request),
+            path,
+        }
+    }
+}
+
+impl Deref for AssetRequest {
+    type Target = Request<Vec<u8>>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.request
+    }
+}
+
+/// A handler that takes an [`AssetRequest`] and returns a future that either loads the asset, or returns `None`.
+/// This handler is stashed indefinitely in a context object, so it must be `'static`.
+pub trait AssetHandler<F: AssetFuture>: Send + Sync + 'static {
+    /// Handle an asset request, returning a future that either loads the asset, or returns `None`
+    fn handle_request(&self, request: &AssetRequest) -> F;
+}
+
+impl<F: AssetFuture, T: Fn(&AssetRequest) -> F + Send + Sync + 'static> AssetHandler<F> for T {
+    fn handle_request(&self, request: &AssetRequest) -> F {
+        self(request)
+    }
+}
+
+type AssetHandlerRegistryInner =
+    Slab<Box<dyn Fn(&AssetRequest) -> Pin<Box<dyn AssetFuture>> + Send + Sync + 'static>>;
+
+#[derive(Clone)]
+pub struct AssetHandlerRegistry(Arc<RwLock<AssetHandlerRegistryInner>>);
+
+impl AssetHandlerRegistry {
+    pub fn new() -> Self {
+        AssetHandlerRegistry(Arc::new(RwLock::new(Slab::new())))
+    }
+
+    pub async fn register_handler<F: AssetFuture>(&self, f: impl AssetHandler<F>) -> usize {
+        let mut registry = self.0.write().await;
+        registry.insert(Box::new(move |req| Box::pin(f.handle_request(req))))
+    }
+
+    pub async fn remove_handler(&self, id: usize) -> Option<()> {
+        let mut registry = self.0.write().await;
+        registry.try_remove(id).map(|_| ())
+    }
+
+    pub async fn try_handlers(&self, req: &AssetRequest) -> Option<AssetResponse> {
+        let registry = self.0.read().await;
+        for (_, handler) in registry.iter() {
+            if let Some(response) = handler(req).await {
+                return Some(response);
+            }
+        }
+        None
+    }
+}
+
+/// A handle to a registered asset handler.
+pub struct AssetHandlerHandle {
+    pub(crate) desktop: DesktopContext,
+    pub(crate) handler_id: Rc<OnceCell<usize>>,
+}
+
+impl AssetHandlerHandle {
+    /// Returns the ID for this handle.
+    ///
+    /// Because registering an ID is asynchronous, this may return `None` if the
+    /// registration has not completed yet.
+    pub fn handler_id(&self) -> Option<usize> {
+        self.handler_id.get().copied()
+    }
+}
+
+impl Drop for AssetHandlerHandle {
+    fn drop(&mut self) {
+        let cell = Rc::clone(&self.handler_id);
+        let desktop = Rc::clone(&self.desktop);
+        tokio::task::block_in_place(move || {
+            Handle::current().block_on(async move {
+                if let Some(id) = cell.get() {
+                    desktop.asset_handlers.remove_handler(*id).await;
+                }
+            })
+        });
+    }
+}