fix wasm assets (#714)

fix wasm assets

crates/bevy_asset/Cargo.toml

@@ -37,7 +37,6 @@ log = { version = "0.4", features = ["release_max_level_info"] }
 notify = { version = "5.0.0-pre.2", optional = true }
 parking_lot = "0.11.0"
 rand = "0.7.3"
-async-trait = "0.1.40"
 
 [target.'cfg(target_arch = "wasm32")'.dependencies]
 wasm-bindgen = { version = "0.2" }

crates/bevy_asset/src/io/file_asset_io.rs

@@ -1,7 +1,6 @@
 use crate::{filesystem_watcher::FilesystemWatcher, AssetIo, AssetIoError, AssetServer};
 use anyhow::Result;
-use async_trait::async_trait;
+use bevy_ecs::{bevy_utils::BoxedFuture, Res};
-use bevy_ecs::Res;
 use bevy_utils::HashSet;
 use crossbeam_channel::TryRecvError;
 use fs::File;
@@ -42,9 +41,9 @@ impl FileAssetIo {
     }
 }
 
-#[async_trait]
 impl AssetIo for FileAssetIo {
-    async fn load_path(&self, path: &Path) -> Result<Vec<u8>, AssetIoError> {
+    fn load_path<'a>(&'a self, path: &'a Path) -> BoxedFuture<'a, Result<Vec<u8>, AssetIoError>> {
+        Box::pin(async move {
             let mut bytes = Vec::new();
             match File::open(self.root_path.join(path)) {
                 Ok(mut file) => {
@@ -59,6 +58,7 @@ impl AssetIo for FileAssetIo {
                 }
             }
             Ok(bytes)
+        })
     }
 
     fn read_directory(
@@ -103,7 +103,7 @@ impl AssetIo for FileAssetIo {
     }
 }
 
-#[cfg(feature = "filesystem_watcher")]
+#[cfg(all(feature = "filesystem_watcher", not(target_arch = "wasm32")))]
 pub fn filesystem_watcher_system(asset_server: Res<AssetServer>) {
     let mut changed = HashSet::default();
     let asset_io =

crates/bevy_asset/src/io/mod.rs

@@ -9,7 +9,7 @@ pub use file_asset_io::*;
 pub use wasm_asset_io::*;
 
 use anyhow::Result;
-use async_trait::async_trait;
+use bevy_ecs::bevy_utils::BoxedFuture;
 use downcast_rs::{impl_downcast, Downcast};
 use std::{
     io,
@@ -29,10 +29,8 @@ pub enum AssetIoError {
 }
 
 /// Handles load requests from an AssetServer
-#[cfg_attr(target_arch = "wasm32", async_trait(?Send))]
-#[cfg_attr(not(target_arch = "wasm32"), async_trait)]
 pub trait AssetIo: Downcast + Send + Sync + 'static {
-    async fn load_path(&self, path: &Path) -> Result<Vec<u8>, AssetIoError>;
+    fn load_path<'a>(&'a self, path: &'a Path) -> BoxedFuture<'a, Result<Vec<u8>, AssetIoError>>;
     fn read_directory(
         &self,
         path: &Path,

crates/bevy_asset/src/io/wasm_asset_io.rs

@@ -1,6 +1,6 @@
 use crate::{AssetIo, AssetIoError};
 use anyhow::Result;
-use async_trait::async_trait;
+use bevy_ecs::bevy_utils::BoxedFuture;
 use js_sys::Uint8Array;
 use std::path::{Path, PathBuf};
 use wasm_bindgen::JsCast;
@@ -19,9 +19,9 @@ impl WasmAssetIo {
     }
 }
 
-#[async_trait(?Send)]
 impl AssetIo for WasmAssetIo {
-    async fn load_path(&self, path: &Path) -> Result<Vec<u8>, AssetIoError> {
+    fn load_path<'a>(&'a self, path: &'a Path) -> BoxedFuture<'a, Result<Vec<u8>, AssetIoError>> {
+        Box::pin(async move {
             let path = self.root_path.join(path);
             let window = web_sys::window().unwrap();
             let resp_value = JsFuture::from(window.fetch_with_str(path.to_str().unwrap()))
@@ -31,6 +31,7 @@ impl AssetIo for WasmAssetIo {
             let data = JsFuture::from(resp.array_buffer().unwrap()).await.unwrap();
             let bytes = Uint8Array::new(&data).to_vec();
             Ok(bytes)
+        })
     }
 
     fn read_directory(

crates/bevy_utils/src/lib.rs

@@ -3,7 +3,12 @@ use std::{future::Future, pin::Pin};
 
 pub use ahash::AHasher;
 
+#[cfg(not(target_arch = "wasm32"))]
 pub type BoxedFuture<'a, T> = Pin<Box<dyn Future<Output = T> + Send + 'a>>;
+
+#[cfg(target_arch = "wasm32")]
+pub type BoxedFuture<'a, T> = Pin<Box<dyn Future<Output = T> + 'a>>;
+
 pub type HashMap<K, V> = std::collections::HashMap<K, V, RandomState>;
 pub type HashSet<K> = std::collections::HashSet<K, RandomState>;