Process Asset File Extensions With Multiple Dots

Fixes #1276

crates/bevy_asset/src/asset_server.rs

@@ -18,7 +18,7 @@ use thiserror::Error;
 pub enum AssetServerError {
     #[error("asset folder path is not a directory")]
     AssetFolderNotADirectory(String),
-    #[error("no AssetLoader found for the given extension")]
+    #[error("no AssetLoader found{}", format_missing_asset_ext(.0))]
     MissingAssetLoader(Option<String>),
     #[error("the given type does not match the type of the loaded asset")]
     IncorrectHandleType,
@@ -28,6 +28,13 @@ pub enum AssetServerError {
     PathLoaderError(#[from] AssetIoError),
 }
 
+fn format_missing_asset_ext(ext: &Option<String>) -> String {
+    return ext
+        .as_ref()
+        .map(|x| format!(" for the following extension(s): {}", x))
+        .unwrap_or_default();
+}
+
 #[derive(Default)]
 pub(crate) struct AssetRefCounter {
     pub(crate) channel: Arc<RefChangeChannel>,
@@ -132,11 +139,25 @@ impl AssetServer {
         &self,
         path: P,
     ) -> Result<Arc<Box<dyn AssetLoader>>, AssetServerError> {
-        path.as_ref()
-            .extension()
-            .and_then(|e| e.to_str())
-            .ok_or(AssetServerError::MissingAssetLoader(None))
-            .and_then(|extension| self.get_asset_loader(extension))
+        let s = path
+            .as_ref()
+            .file_name()
+            .ok_or(AssetServerError::MissingAssetLoader(None))?
+            .to_str()
+            .ok_or(AssetServerError::MissingAssetLoader(None))?;
+
+        let mut exts = Vec::new();
+        let mut ext = s;
+        while let Some(idx) = ext.find('.') {
+            ext = &ext[idx + 1..];
+            exts.push(ext);
+            if let Ok(loader) = self.get_asset_loader(ext) {
+                return Ok(loader);
+            }
+        }
+        let e = AssetServerError::MissingAssetLoader(Some(exts.join(", ")));
+        eprintln!("{}", e);
+        Err(e)
     }
 
     pub fn get_handle_path<H: Into<HandleId>>(&self, handle: H) -> Option<AssetPath<'_>> {
@@ -444,3 +465,100 @@ impl AssetServer {
 pub fn free_unused_assets_system(asset_server: Res<AssetServer>) {
     asset_server.free_unused_assets();
 }
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use bevy_utils::BoxedFuture;
+
+    struct FakePngLoader;
+    impl AssetLoader for FakePngLoader {
+        fn load<'a>(
+            &'a self,
+            _: &'a [u8],
+            _: &'a mut LoadContext,
+        ) -> BoxedFuture<'a, Result<(), anyhow::Error>> {
+            Box::pin(async move { Ok(()) })
+        }
+
+        fn extensions(&self) -> &[&str] {
+            &["png"]
+        }
+    }
+
+    struct FakeMultipleDotLoader;
+    impl AssetLoader for FakeMultipleDotLoader {
+        fn load<'a>(
+            &'a self,
+            _: &'a [u8],
+            _: &'a mut LoadContext,
+        ) -> BoxedFuture<'a, Result<(), anyhow::Error>> {
+            Box::pin(async move { Ok(()) })
+        }
+
+        fn extensions(&self) -> &[&str] {
+            &["test.png"]
+        }
+    }
+
+    fn setup() -> AssetServer {
+        use crate::FileAssetIo;
+
+        let asset_server = AssetServer {
+            server: Arc::new(AssetServerInternal {
+                loaders: Default::default(),
+                extension_to_loader_index: Default::default(),
+                asset_sources: Default::default(),
+                asset_ref_counter: Default::default(),
+                handle_to_path: Default::default(),
+                asset_lifecycles: Default::default(),
+                task_pool: Default::default(),
+                asset_io: Box::new(FileAssetIo::new(&".")),
+            }),
+        };
+        asset_server.add_loader::<FakePngLoader>(FakePngLoader);
+        asset_server.add_loader::<FakeMultipleDotLoader>(FakeMultipleDotLoader);
+        asset_server
+    }
+
+    #[test]
+    fn extensions() {
+        let asset_server = setup();
+        let t = asset_server.get_path_asset_loader("test.png");
+        assert_eq!(t.unwrap().extensions()[0], "png");
+    }
+
+    #[test]
+    fn no_loader() {
+        let asset_server = setup();
+        let t = asset_server.get_path_asset_loader("test.pong");
+        assert!(t.is_err());
+    }
+
+    #[test]
+    fn multiple_extensions_no_loader() {
+        let asset_server = setup();
+
+        assert!(
+            match asset_server.get_path_asset_loader("test.v1.2.3.pong") {
+                Err(AssetServerError::MissingAssetLoader(Some(ext))) =>
+                    ext == "v1.2.3.pong, 2.3.pong, 3.pong, pong",
+                _ => false,
+            }
+        )
+    }
+
+    #[test]
+    fn filename_with_dots() {
+        let asset_server = setup();
+        let t = asset_server.get_path_asset_loader("test-v1.2.3.png");
+        assert_eq!(t.unwrap().extensions()[0], "png");
+    }
+
+    #[test]
+    fn multiple_extensions() {
+        let asset_server = setup();
+        let t = asset_server.get_path_asset_loader("test.test.png");
+        assert_eq!(t.unwrap().extensions()[0], "test.png");
+    }
+}