Initial Implementation of temp:// Asset Source

Author: bushrat011899

crates/bevy_asset/Cargo.toml

@@ -41,6 +41,7 @@ ron = "0.8"
 serde = { version = "1", features = ["derive"] }
 thiserror = "1.0"
 uuid = { version = "1.0", features = ["v4"] }
+tempfile = "3.10.1"
 
 [target.'cfg(target_os = "android")'.dependencies]
 bevy_winit = { path = "../bevy_winit", version = "0.14.0-dev" }

crates/bevy_asset/src/lib.rs

@@ -30,6 +30,7 @@ mod loader;
 mod path;
 mod reflect;
 mod server;
+mod temp;
 
 pub use assets::*;
 pub use bevy_asset_macros::Asset;
@@ -46,6 +47,7 @@ pub use server::*;
 
 /// Rusty Object Notation, a crate used to serialize and deserialize bevy assets.
 pub use ron;
+use temp::TempAssetPlugin;
 
 use crate::{
     io::{embedded::EmbeddedAssetRegistry, AssetSourceBuilder, AssetSourceBuilders, AssetSourceId},
@@ -91,6 +93,9 @@ pub struct AssetPlugin {
     pub mode: AssetMode,
     /// How/If asset meta files should be checked.
     pub meta_check: AssetMetaCheck,
+    /// The path to use for temporary assets (relative to the project root).
+    /// If not provided, a platform specific folder will be created and deleted upon exit.
+    pub temporary_file_path: Option<String>,
 }
 
 #[derive(Debug)]
@@ -138,6 +143,7 @@ impl Default for AssetPlugin {
             processed_file_path: Self::DEFAULT_PROCESSED_FILE_PATH.to_string(),
             watch_for_changes_override: None,
             meta_check: AssetMetaCheck::default(),
+            temporary_file_path: None,
         }
     }
 }
@@ -219,7 +225,10 @@ impl Plugin for AssetPlugin {
             .add_event::<UntypedAssetLoadFailedEvent>()
             .configure_sets(PreUpdate, TrackAssets.after(handle_internal_asset_events))
             .add_systems(PreUpdate, handle_internal_asset_events)
-            .register_type::<AssetPath>();
+            .register_type::<AssetPath>()
+            .add_plugins(TempAssetPlugin {
+                temporary_file_path: self.temporary_file_path.clone(),
+            });
     }
 }
 

crates/bevy_asset/src/temp.rs

@@ -0,0 +1,66 @@
+use std::path::{Path, PathBuf};
+
+use bevy_app::Plugin;
+use bevy_ecs::system::Resource;
+
+use crate::io::{AssetSourceBuilder, AssetSourceBuilders};
+
+#[derive(Resource)]
+struct TempAssetDirectory {
+    folder: TempDirectory,
+}
+
+impl TempAssetDirectory {
+    fn path(&self) -> &Path {
+        self.folder.path()
+    }
+}
+
+enum TempDirectory {
+    Delete(tempfile::TempDir),
+    Persist(PathBuf),
+}
+
+impl TempDirectory {
+    fn path(&self) -> &Path {
+        match self {
+            TempDirectory::Delete(x) => x.path(),
+            TempDirectory::Persist(x) => x.as_ref(),
+        }
+    }
+}
+
+/// Plugin providing a temporary asset source.
+#[derive(Default)]
+pub(crate) struct TempAssetPlugin {
+    /// The path to use for temporary assets (relative to the project root).
+    /// If not provided, a platform specific folder will be created and deleted upon exit.
+    pub temporary_file_path: Option<String>,
+}
+
+impl Plugin for TempAssetPlugin {
+    fn build(&self, app: &mut bevy_app::App) {
+        let source = {
+            let temp_dir = app
+                .world_mut()
+                .get_resource_or_insert_with::<TempAssetDirectory>(|| {
+                    let folder = match &self.temporary_file_path {
+                        Some(path) => TempDirectory::Persist(path.into()),
+                        None => TempDirectory::Delete(tempfile::tempdir().expect("todo")),
+                    };
+
+                    TempAssetDirectory { folder }
+                });
+
+            let path = temp_dir.path().to_str().expect("todo");
+
+            AssetSourceBuilder::platform_default(path, None)
+        };
+
+        let mut sources = app
+            .world_mut()
+            .get_resource_or_insert_with::<AssetSourceBuilders>(Default::default);
+
+        sources.insert("temp", source);
+    }
+}