# Objective
- Fixes#10478
## Solution
Generalised `From/Into` implementations over `&str` and `Option<&str>`
for `AssetSourceId` and `AssetPath` across all lifetimes, not just
static. To maintain access to the `'static`-only specialisation, these
types (and `CowArc`) now include an `as_static` method which will apply
the specialisation.
```rust
// Snipped from `AssetApp`
fn register_asset_source(
&mut self,
id: impl Into<AssetSourceId<'static>>,
// ^^^^^^^
// | as_static is only available for 'static lifetimes
source: AssetSourceBuilder,
) -> &mut Self {
let id = id.into().as_static();
// ^^^^^^ ^^^^^^^^^
// | | Specialized (internally storing CowArc::Static)
// | Generic Into (internally storing CowArc::Borrowed)
// ...
}
```
This post-fix specialisation is available here because the actual
specialisation performed is only a marker for if/when modification or
ownership is required, making the transform a very cheap operation. For
cleanliness, I've also added `from_static`, which wraps this behaviour
in a clean shorthand designed to replace `from` calls.
---
## Changelog
- Generalised the following implementations over a generic lifetime:
- `From<&'static str> for AssetSourceId<'static>`
- `From<Option<&'static str>> for AssetSourceId<'static>`
- `From<&'static str> for AssetPath<'static>`
- `From<&'static Path> for AssetPath<'static>`
- Added `as_static` specialisation to:
- `CowArc`
- `AssetSourceId`
- `AssetPath`
- Added `from_static` specialised constructor to:
- `AssetSourceId`
- `AssetPath`
## Migration Guide
In areas where these implementations where being used, you can now add
`from_static` in order to get the original specialised implementation
which avoids creating an `Arc` internally.
```rust
// Before
let asset_path = AssetPath::from("my/path/to/an/asset.ext");
// After
let asset_path = AssetPath::from_static("my/path/to/an/asset.ext");
```
To be clear, this is only required if you wish to maintain the
performance benefit that came with the specialisation. Existing code is
_not_ broken by this change.
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