lyra-resource/Cargo.toml

@@ -8,6 +8,7 @@ edition = "2021"
 [dependencies]
 anyhow = "1.0.75"
 base64 = "0.21.4"
+crossbeam = { version = "0.8.4", features = [ "crossbeam-channel" ] }
 edict = "0.5.0"
 glam = "0.24.1"
 gltf = { version = "1.3.0", features = ["KHR_materials_pbrSpecularGlossiness", "KHR_materials_specular"] }
@@ -15,6 +16,8 @@ image = "0.24.7"
 # not using custom matcher, or file type from file path
 infer = { version = "0.15.0", default-features = false }
 mime = "0.3.17"
+notify = "6.1.1"
+#notify = { version = "6.1.1", default-features = false, features = [ "fsevent-sys", "macos_fsevent" ]} # disables crossbeam-channel
 percent-encoding = "2.3.0"
 thiserror = "1.0.48"
 tracing = "0.1.37"

lyra-resource/src/loader/image.rs

@@ -2,7 +2,7 @@ use std::{fs::File, sync::Arc, io::Read};
 
 use image::ImageError;
 
-use crate::{resource_manager::ResourceStorage, texture::Texture, resource::Resource, ResourceManager};
+use crate::{resource_manager::ResourceStorage, texture::Texture, resource::ResHandle, ResourceManager};
 
 use super::{LoaderError, ResourceLoader};
 
@@ -62,7 +62,7 @@ impl ResourceLoader for ImageLoader {
         let texture = Texture {
             image,
         };
-        let res = Resource::with_data(path, texture);
+        let res = ResHandle::with_data(path, texture);
 
         Ok(Arc::new(res))
     }
@@ -76,7 +76,7 @@ impl ResourceLoader for ImageLoader {
         let texture = Texture {
             image,
         };
-        let res = Resource::with_data(&uuid::Uuid::new_v4().to_string(), texture);
+        let res = ResHandle::with_data(&uuid::Uuid::new_v4().to_string(), texture);
         
         Ok(Arc::new(res))
     }

lyra-resource/src/loader/model.rs

@@ -2,7 +2,7 @@ use std::{sync::Arc, path::PathBuf};
 
 use thiserror::Error;
 
-use crate::{ResourceLoader, LoaderError, Mesh, Model, MeshVertexAttribute, VertexAttributeData, Resource, Material, MeshIndices, ResourceManager, util};
+use crate::{ResourceLoader, LoaderError, Mesh, Model, MeshVertexAttribute, VertexAttributeData, ResHandle, Material, MeshIndices, ResourceManager, util};
 
 use tracing::debug;
 
@@ -189,7 +189,7 @@ impl ResourceLoader for ModelLoader {
             .collect();
         debug!("Loaded {} meshes, and {} materials from '{}'", meshes.len(), materials.len(), path);
 
-        Ok(Arc::new(Resource::with_data(path, Model::new(meshes))))
+        Ok(Arc::new(ResHandle::with_data(path, Model::new(meshes))))
     }
 
     #[allow(unused_variables)]
@@ -216,8 +216,8 @@ mod tests {
         let mut manager = ResourceManager::new();
         let loader = ModelLoader::default();
         let model = loader.load(&mut manager, &path).unwrap();
-        let model = Arc::downcast::<Resource<Model>>(model.as_arc_any()).unwrap();
-        let model = model.data.as_ref().unwrap();
+        let model = Arc::downcast::<ResHandle<Model>>(model.as_arc_any()).unwrap();
+        let model = model.data_ref();
         assert_eq!(model.meshes.len(), 1); // There should only be 1 mesh
         let mesh = &model.meshes[0];
         assert!(mesh.position().unwrap().len() > 0);

lyra-resource/src/resource.rs

@@ -1,4 +1,4 @@
-use std::sync::Arc;
+use std::sync::{Arc, RwLock};
 
 use uuid::Uuid;
 
@@ -8,25 +8,140 @@ pub enum ResourceState {
     Ready,
 }
 
-#[derive(Clone)]
-pub struct Resource<T> {
-    pub path: String,
-    pub data: Option<Arc<T>>,
-    pub uuid: Uuid,
-    pub state: ResourceState,
+pub struct ResourceDataRef<'a, T> {
+    guard: std::sync::RwLockReadGuard<'a, Resource<T>>,
 }
 
-/// A helper type to make it easier to use resources
-pub type ResHandle<T> = Arc<Resource<T>>;
+impl<'a, T> std::ops::Deref for ResourceDataRef<'a, T> {
+    type Target = T;
 
-impl<T> Resource<T> {
-    /// Create the resource with data, its assumed the state is `Ready`
-    pub fn with_data(path: &str, data: T) -> Self {
-        Self {
-            path: path.to_string(),
-            data: Some(Arc::new(data)),
-            uuid: Uuid::new_v4(),
-            state: ResourceState::Ready,
-        }
+    fn deref(&self) -> &Self::Target {
+        // safety: this struct must only be created if the resource is loaded
+        self.guard.data.as_ref().unwrap()
     }
 }
+
+pub(crate) struct Resource<T> {
+    path: String,
+    pub(crate) data: Option<T>,
+    pub(crate) version: usize,
+    pub(crate) state: ResourceState,
+    uuid: Uuid,
+}
+
+/// A handle to a resource. 
+/// 
+/// # Note
+/// This struct has an inner [`RwLock`] to the resource data, so most methods may be blocking.
+/// However, the only times it will be blocking is if another thread is reloading the resource
+/// and has a write lock on the data. This means that most of the time, it is not blocking.
+pub struct ResHandle<T> {
+    pub(crate) data: Arc<RwLock<Resource<T>>>,
+}
+
+impl<T> Clone for ResHandle<T> {
+    fn clone(&self) -> Self {
+        Self { data: self.data.clone() }
+    }
+}
+
+impl<T> ResHandle<T> {
+    /// Create the resource with data, its assumed the state is `Ready`
+    pub fn with_data(path: &str, data: T) -> Self {
+        let res_version = Resource {
+            path: path.to_string(),
+            data: Some(data),
+            version: 0,
+            state: ResourceState::Ready,
+            uuid: Uuid::new_v4(),
+        };
+
+        Self {
+            data: Arc::new(RwLock::new(res_version)),
+        }
+    }
+
+    /// Returns a boolean indicated if this resource is loaded
+    pub fn is_loaded(&self) -> bool {
+        let d = self.data.read().expect("Resource mutex was poisoned!");
+        d.state == ResourceState::Ready
+    }
+
+    /// Returns the current state of the resource.
+    pub fn state(&self) -> ResourceState {
+        let d = self.data.read().expect("Resource mutex was poisoned!");
+        d.state
+    }
+
+    /// Returns the path that the resource was loaded from.
+    pub fn path(&self) -> String {
+        let d = self.data.read().expect("Resource mutex was poisoned!");
+        d.path.to_string()
+    }
+
+    /// Returns the uuid of the resource.
+    pub fn uuid(&self) -> Uuid {
+        let d = self.data.read().expect("Resource mutex was poisoned!");
+        d.uuid
+    }
+
+    /// Retrieves the current version of the resource. This gets incremented when the resource
+    /// is reloaded.
+    pub fn version(&self) -> usize {
+        let d = self.data.read().expect("Resource mutex was poisoned!");
+        d.version
+    }
+
+    /// Get a reference to the data in the resource
+    ///
+    /// # Panics
+    /// Panics if the resource was not loaded yet.
+    pub fn data_ref<'a>(&'a self) -> ResourceDataRef<'a, T> {
+        let d = self.data.read().expect("Resource mutex was poisoned!");
+        ResourceDataRef {
+            guard: d
+        }
+    }
+
+    /// Attempt to get a borrow to the resource data. Returns `None` if the resource is not loaded.
+    pub fn try_data_ref<'a>(&'a self) -> Option<ResourceDataRef<'a, T>> {
+        if self.is_loaded() {
+            let d = self.data.read().expect("Resource mutex was poisoned!");
+            Some(ResourceDataRef {
+                guard: d
+            })
+        } else {
+            None
+        }
+    }
+
+    /* /// Get a reference to the data in the resource
+    ///
+    /// # Panics
+    /// Panics if the resource was not loaded yet.
+    pub fn data_ref(&self) -> &T {
+        self.data.as_ref()
+            .expect("Resource is not loaded yet (use try_data_ref, or wait until its loaded)!")
+    }
+
+    /// If the resource is loaded, returns `Some` reference to the data in the resource,
+    /// else it will return `None`
+    pub fn try_data_ref(&self) -> Option<&T> {
+        self.data.as_ref()
+    }
+
+    /// Get a **mutable** reference to the data in the resource
+    ///
+    /// # Panics
+    /// Panics if the resource was not loaded yet.
+    pub fn data_mut(&mut self) -> &mut T {
+        self.data.as_mut()
+            .expect("Resource is not loaded yet (use try_data_ref, or wait until its loaded)!")
+    }
+
+    /// If the resource is loaded, returns `Some` **mutable** reference to the data in the resource,
+    /// else it will return `None`
+    pub fn try_data_mut(&mut self) -> Option<&mut T> {
+        self.data.as_mut()
+    } */
+}

lyra-resource/src/resource_manager.rs

@@ -1,13 +1,16 @@
-use std::{sync::Arc, collections::HashMap, any::Any};
+use std::{sync::{Arc, RwLock}, collections::{HashMap, VecDeque}, any::Any, thread::{Thread, JoinHandle}, rc::Rc, path::Path, ops::Deref};
 
+use crossbeam::channel::{Receiver, Sender};
+use notify::{Watcher, RecommendedWatcher};
 use thiserror::Error;
 
-use crate::{resource::Resource, loader::{ResourceLoader, LoaderError, image::ImageLoader, model::ModelLoader}};
+use crate::{resource::ResHandle, loader::{ResourceLoader, LoaderError, image::ImageLoader, model::ModelLoader}};
 
 pub trait ResourceStorage: Send + Sync + Any + 'static {
     fn as_any(&self) -> &dyn Any;
     fn as_any_mut(&mut self) -> &mut dyn Any;
     fn as_arc_any(self: Arc<Self>) -> Arc<dyn Any + Send + Sync>;
+    fn as_box_any(self: Box<Self>) -> Box<dyn Any + Send + Sync>;
 }
 
 /// Implements this trait for anything that fits the type bounds
@@ -23,6 +26,10 @@ impl<T: Send + Sync + 'static> ResourceStorage for T {
     fn as_arc_any(self: Arc<Self>) -> Arc<dyn Any + Send + Sync> {
         self.clone()
     }
+
+    fn as_box_any(self: Box<Self>) -> Box<dyn Any + Send + Sync> {
+        self
+    }
 }
 
 #[derive(Error, Debug)]
@@ -46,9 +53,16 @@ impl From<LoaderError> for RequestError {
 /// A struct that stores all Manager data. This is requried for sending 
 //struct ManagerStorage
 
+/// A struct that
+pub struct ResourceWatcher {
+    watcher: Arc<RwLock<dyn notify::Watcher>>,
+    events_recv: Receiver<notify::Result<notify::Event>>,
+}
+
 pub struct ResourceManager {
     resources: HashMap<String, Arc<dyn ResourceStorage>>,
     loaders: Vec<Arc<dyn ResourceLoader>>,
+    watchers: HashMap<String, ResourceWatcher>,
 }
 
 impl Default for ResourceManager {
@@ -62,6 +76,7 @@ impl ResourceManager {
         Self {
             resources: HashMap::new(),
             loaders: vec![ Arc::new(ImageLoader), Arc::new(ModelLoader) ],
+            watchers: HashMap::new(),
         }
     }
 
@@ -73,11 +88,15 @@ impl ResourceManager {
         self.loaders.push(Arc::new(L::default()));
     }
 
-    pub fn request<T: Send + Sync + Any + 'static>(&mut self, path: &str) -> Result<Arc<Resource<T>>, RequestError> {
+    pub fn request<T>(&mut self, path: &str) -> Result<ResHandle<T>, RequestError>
+    where
+        T: Send + Sync + Any + 'static
+    {
         match self.resources.get(&path.to_string()) {
             Some(res) => {
                 let res = res.clone().as_arc_any();
-                let res = res.downcast::<Resource<T>>().expect("Failure to downcast resource");
+                let res: Arc<ResHandle<T>> = res.downcast::<ResHandle<T>>().expect("Failure to downcast resource");
+                let res = ResHandle::<T>::clone(&res);
 
                 Ok(res)
             },
@@ -88,12 +107,14 @@ impl ResourceManager {
                     // Load the resource and store it
                     let loader = Arc::clone(loader); // stop borrowing from self
                     let res = loader.load(self, path)?;
+                    let res: Arc<dyn ResourceStorage> = Arc::from(res);
                     self.resources.insert(path.to_string(), res.clone());
 
                     // cast Arc<dyn ResourceStorage> to Arc<Resource<T>
                     let res = res.as_arc_any();
-                    let res = res.downcast::<Resource<T>>()
+                    let res = res.downcast::<ResHandle<T>>()
                         .expect("Failure to downcast resource! Does the loader return an `Arc<Resource<T>>`?");
+                    let res = ResHandle::<T>::clone(&res);
 
                     Ok(res)
                 } else {
@@ -112,18 +133,23 @@ impl ResourceManager {
     /// * `bytes` - The bytes to store.
     /// 
     /// Returns: The `Arc` to the now stored resource
-    pub fn load_bytes<T: Send + Sync + Any + 'static>(&mut self, ident: &str, mime_type: &str, bytes: Vec<u8>, offset: usize, length: usize) -> Result<Arc<Resource<T>>, RequestError> {
+    pub fn load_bytes<T>(&mut self, ident: &str, mime_type: &str, bytes: Vec<u8>, offset: usize, length: usize) -> Result<ResHandle<T>, RequestError>
+    where
+        T: Send + Sync + Any + 'static
+    {
         if let Some(loader) = self.loaders.iter()
                 .find(|l| l.does_support_mime(mime_type)) {
             let loader = loader.clone();
             let res = loader.load_bytes(self, bytes, offset, length)?;
+            let res: Arc<dyn ResourceStorage> = Arc::from(res);
             self.resources.insert(ident.to_string(), res.clone());
             // code here...
 
             // cast Arc<dyn ResourceStorage> to Arc<Resource<T>
             let res = res.as_arc_any();
-            let res = res.downcast::<Resource<T>>()
+            let res = res.downcast::<ResHandle<T>>()
                 .expect("Failure to downcast resource! Does the loader return an `Arc<Resource<T>>`?");
+            let res = ResHandle::<T>::clone(&res);
 
             Ok(res)
         } else {
@@ -132,11 +158,14 @@ impl ResourceManager {
     }
 
     /// Requests bytes from the manager.
-    pub fn request_loaded_bytes<T: Send + Sync + Any + 'static>(&mut self, ident: &str) -> Result<Arc<Resource<T>>, RequestError> {
+    pub fn request_loaded_bytes<T>(&mut self, ident: &str) -> Result<Arc<ResHandle<T>>, RequestError>
+    where
+        T: Send + Sync + Any + 'static
+    {
         match self.resources.get(&ident.to_string()) {
             Some(res) => {
                 let res = res.clone().as_arc_any();
-                let res = res.downcast::<Resource<T>>().expect("Failure to downcast resource");
+                let res = res.downcast::<ResHandle<T>>().expect("Failure to downcast resource");
 
                 Ok(res)
             },
@@ -145,6 +174,81 @@ impl ResourceManager {
             }
         }
     }
+
+    /// Start watching a path for changes. Returns a mspc channel that will send events
+    pub fn watch(&mut self, path: &str, recursive: bool) -> notify::Result<Receiver<notify::Result<notify::Event>>> {        
+        let (send, recv) = crossbeam::channel::bounded(15);
+        let mut watcher = RecommendedWatcher::new(send, notify::Config::default())?;
+
+        let recurse_mode = match recursive {
+            true => notify::RecursiveMode::Recursive,
+            false => notify::RecursiveMode::NonRecursive,
+        };
+        watcher.watch(path.as_ref(), recurse_mode)?;
+
+        let watcher = Arc::new(RwLock::new(watcher));
+        let watcher = ResourceWatcher {
+            watcher,
+            events_recv: recv.clone(),
+        };
+
+        self.watchers.insert(path.to_string(), watcher);
+
+        Ok(recv)
+    }
+
+    /// Stops watching a path
+    pub fn stop_watching(&mut self, path: &str) -> notify::Result<()> {
+        if let Some(watcher) = self.watchers.get(path) {
+            let mut watcher = watcher.watcher.write().unwrap();
+            watcher.unwatch(Path::new(path))?;
+        }
+
+        Ok(())
+    }
+
+    /// Returns a mspc receiver for watcher events of a specific path. The path must already
+    /// be watched with [`ResourceManager::watch`] for this to return `Some`.
+    pub fn watcher_event_recv(&self, path: &str) -> Option<Receiver<notify::Result<notify::Event>>> {
+        self.watchers.get(&path.to_string())
+            .map(|w| w.events_recv.clone())
+    }
+
+    /// Reloads a resource. The data inside the resource will be updated, the state may
+    pub fn reload<T>(&mut self, resource: ResHandle<T>) -> Result<(), RequestError>
+    where
+        T: Send + Sync + Any + 'static
+    {
+        let path = resource.path();
+        if let Some(loader) = self.loaders.iter()
+                .find(|l| l.does_support_file(&path)) {
+            let loader = Arc::clone(loader); // stop borrowing from self
+            let loaded = loader.load(self, &path)?;
+            let loaded = loaded.as_arc_any();
+            
+            let loaded = loaded.downcast::<ResHandle<T>>()
+                .unwrap();
+            let loaded = match Arc::try_unwrap(loaded) {
+                Ok(v) => v,
+                Err(_) => panic!("Seems impossible that this would happen, the resource was just loaded!"),
+            };
+            let loaded = loaded.data;
+            let loaded = match Arc::try_unwrap(loaded) {
+                Ok(v) => v,
+                Err(_) => panic!("Seems impossible that this would happen, the resource was just loaded!"),
+            };
+            let loaded = loaded.into_inner().unwrap();
+
+            let res_lock = &resource.data;
+            let mut res_lock = res_lock.write().unwrap();
+            let version = res_lock.version;
+            // safe since loaded was JUST loaded, it will be unlocked and not poisoned
+            *res_lock = loaded;
+            res_lock.version = version + 1;
+        }
+
+        Ok(())
+    }
 }
 
 #[cfg(test)]
@@ -165,20 +269,20 @@ mod tests {
     fn load_image() {
         let mut man = ResourceManager::new();
         let res = man.request::<Texture>(&get_image("squiggles.png")).unwrap();
-        assert_eq!(res.state, ResourceState::Ready);
-        let img = res.data.as_ref();
+        assert_eq!(res.state(), ResourceState::Ready);
+        let img = res.try_data_ref();
         img.unwrap();
     }
 
-    /// Ensures that only one copy of the same thing made
+    /// Ensures that only one copy of the same data was made
     #[test]
     fn ensure_single() {
         let mut man = ResourceManager::new();
         let res = man.request::<Texture>(&get_image("squiggles.png")).unwrap();
-        assert_eq!(Arc::strong_count(&res), 2);
+        assert_eq!(Arc::strong_count(&res.data), 2);
 
         let resagain = man.request::<Texture>(&get_image("squiggles.png")).unwrap();
-        assert_eq!(Arc::strong_count(&resagain), 3);
+        assert_eq!(Arc::strong_count(&resagain.data), 3);
     }
 
     /// Ensures that an error is returned when a file that doesn't exist is requested
@@ -196,4 +300,45 @@ mod tests {
             }
         );
     }
+
+    #[test]
+    fn reload_image() {
+        let mut man = ResourceManager::new();
+        let res = man.request::<Texture>(&get_image("squiggles.png")).unwrap();
+        assert_eq!(res.state(), ResourceState::Ready);
+        let img = res.try_data_ref();
+        img.unwrap();
+
+        man.reload(res.clone()).unwrap();
+        assert_eq!(res.version(), 1);
+
+        man.reload(res.clone()).unwrap();
+        assert_eq!(res.version(), 2);
+    }
+
+    #[test]
+    fn watch_image() {
+        let image_path = get_image("squiggles.png");
+        let image_bytes = std::fs::read(&image_path).unwrap();
+
+        let mut man = ResourceManager::new();
+        let res = man.request::<Texture>(&image_path).unwrap();
+        assert_eq!(res.state(), ResourceState::Ready);
+        let img = res.try_data_ref();
+        img.unwrap();
+
+        let recv = man.watch(&image_path, false).unwrap();
+
+        std::fs::remove_file(&image_path).unwrap();
+
+        let event = recv.recv().unwrap();
+        let event = event.unwrap();
+        
+        std::fs::write(image_path, image_bytes).unwrap();
+        
+        println!("Event kind: {:?}", event.kind);
+        
+        // for some reason, 
+        assert!(event.kind.is_remove() || event.kind.is_modify());
+    }
 }