Struct assets_manager::AssetCache

pub struct AssetCache<S = FileSystem> { /* private fields */ }

The main structure of this crate, used to cache assets.

It uses interior mutability, so assets can be added in the cache without requiring a mutable reference, but one is required to remove an asset.

Within the cache, assets are identified with their type and a string. This string is constructed from the asset path, replacing / by . and removing the extension. Given that, you cannot use . in your file names except for the extension.

Note: Using symbolic or hard links within the cached directory can lead to surprising behavior (especially with hot-reloading), and thus should be avoided.

Example

use assets_manager::{Asset, AssetCache, loader};
use serde::Deserialize;

#[derive(Debug, Deserialize)]
struct Point {
    x: i32,
    y: i32,
}

impl Asset for Point {
    const EXTENSION: &'static str = "ron";
    type Loader = loader::RonLoader;
}

// Create a cache
let cache = AssetCache::new("assets")?;

// Get an asset from the file `assets/common/position.ron`
let point_handle = cache.load::<Point>("common.position")?;

// Read it
let point = point_handle.read();
println!("Loaded position: {:?}", point);

// Release the lock
drop(point);

// Use hot-reloading
loop {
    cache.hot_reload();
    println!("Position: {:?}", point_handle.read());
}

Implementations

impl AssetCache<FileSystem>

pub fn new<P: AsRef<Path>>(path: P) -> Result<AssetCache<FileSystem>>

Creates a cache that loads assets from the given directory.

Errors

An error will be returned if path is not valid readable directory.

impl<S: Source> AssetCache<S>

pub fn with_source(source: S) -> AssetCache<S>

Creates a cache that loads assets from the given source and tries to start hot-reloading (if feature hot-reloading is used).

If hot-reloading fails to start, an error is logged.

pub fn without_hot_reloading(source: S) -> AssetCache<S>

Creates a cache that loads assets from the given source.

pub fn source(&self) -> &S

Returns a reference to the cache’s Source.

pub fn no_record<T, F: FnOnce() -> T>(&self, f: F) -> T

Temporarily prevent Compound dependencies to be recorded.

This function disables dependencies recording in Compound::load. Assets loaded during the given closure will not be recorded as dependencies and the currently loading asset will not be reloaded when they are.

When hot-reloading is disabled or if the cache’s Source does not support hot-reloading, this function only returns the result of the closure given as parameter.

pub fn get_cached<A: Storable>(&self, id: &str) -> Option<Handle<'_, A>>

Gets a value from the cache.

The value does not have to be an asset, but if it is not, its type must be marked with the Storable trait.

This function does not attempt to load the value from the source if it is not found in the cache.

pub fn get_or_insert<A: Storable>(&self, id: &str, default: A) -> Handle<'_, A>

Gets a value from the cache or inserts one.

As for get_cached, non-assets types must be marked with Storable.

pub fn contains<A: Storable>(&self, id: &str) -> bool

Returns true if the cache contains the specified asset.

pub fn remove<A: Storable>(&mut self, id: &str) -> bool

Removes an asset from the cache, and returns whether it was present in the cache.

Note that you need a mutable reference to the cache, so you cannot have any Handle, AssetGuard, etc when you call this function.

pub fn take<A: Storable>(&mut self, id: &str) -> Option<A>

Takes ownership on a cached asset.

The corresponding asset is removed from the cache.

pub fn clear(&mut self)

Clears the cache.

Removes all cached assets and directories.

pub fn as_any_cache(&self) -> AnyCache<'_>

Converts to an AnyCache.

pub fn load<A: Compound>(&self, id: &str) -> Result<Handle<'_, A>, Error>

Loads an asset.

If the asset is not found in the cache, it is loaded from the source.

Errors

Errors for Assets can occur in several cases :

• The source could not be read
• Loaded data could not be converted properly
• The asset has no extension

pub fn load_expect<A: Compound>(&self, id: &str) -> Handle<'_, A>

Loads an asset and panic if an error happens.

Panics

Panics if an error happens while loading the asset (see load).

pub fn get_cached_dir<A: DirLoadable>(
    &self,
    id: &str,
    recursive: bool
) -> Option<DirHandle<'_, A>>

Loads an directory from the cache.

This function does not attempt to load the it from the source if it is not found in the cache.

pub fn contains_dir<A: DirLoadable>(&self, id: &str, recursive: bool) -> bool

Returns true if the cache contains the specified directory with the given recursive parameter.

pub fn load_dir<A: DirLoadable>(
    &self,
    id: &str,
    recursive: bool
) -> Result<DirHandle<'_, A>, Error>

Loads all assets of a given type from a directory.

If recursive is true, this function also loads assets recursively from subdirectories.

The directory’s id is constructed the same way as assets. To specify the cache’s root, give the empty string ("") as id.

The returned structure can be use to iterate over the loaded assets.

Errors

An error is returned if the given id does not match a valid readable directory.

When loading a directory recursively, directories that can’t be read are ignored.

pub fn load_owned<A: Compound>(&self, id: &str) -> Result<A, Error>

Loads an owned version of an asset

Note that the asset will not be fetched from the cache nor will it be cached. In addition, hot-reloading does not affect the returned value (if used during Compound::load. It will still be registered as a dependency).

This can be useful if you need ownership on a non-clonable value.

impl<S> AssetCache<S>where
    S: Source + Sync,

pub fn hot_reload(&self)

Available on crate feature hot-reloading only.

Reloads changed assets.

This function is typically called within a loop.

If an error occurs while reloading an asset, a warning will be logged and the asset will be left unchanged.

This function blocks the current thread until all changed assets are reloaded, but it does not perform any I/O. However, it needs to lock some assets for writing, so you must not have any AssetGuard from the given AssetCache, or you might experience deadlocks. You are free to keep Handles, though.

If self.source() was created without hot-reloading or if it failed to start, this function is a no-op.

pub fn enhance_hot_reloading(&'static self)

Available on crate feature hot-reloading only.

Enhances hot-reloading.

Having a 'static reference to the cache enables some optimizations, which you can take advantage of with this function. If an AssetCache is behind a 'static reference, you should always prefer using this function over hot_reload.

You only have to call this function once for it to take effect. After calling this function, subsequent calls to hot_reload and to this function have no effect.

If self.source() was created without hot-reloading or if it failed to start, this function is a no-op.

Trait Implementations

impl<S> Debug for AssetCache<S>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.