# Objective
- Make working with `bevy_time` more ergonomic in `no_std` environments.
Currently `bevy_time` expects the getter in environments where time
can't be obtained automatically via the instruction set or the standard
library to be of type `*mut fn() -> Duration`.
[`fn()`](https://doc.rust-lang.org/beta/std/primitive.fn.html) is
already a function pointer, so `*mut fn()` is a _pointer to a function
pointer_. This is harder to use and error prone since creating a pointer
out of something like `&mut fn() -> Duration` when the lifetime of the
reference isn't static will lead to an undefined behavior once the
reference is freed
## Solution
- Accept a `fn() -> Duration` instead
## Testing
- I made a whole game on the Playdate that relies on `bevy_time`
heavily, see:
[bevydate_time](1b4f02adcd/src/lib.rs (L510-L546))
for usage of the Instant's getter.
---
## Showcase
<details>
<summary>Click to view showcase</summary>
https://github.com/user-attachments/assets/f687847f-6b62-4322-95f3-c908ada3db30
</details>
## Migration Guide
This is a breaking change but it's not for people coming from Bevy v0.15
### Small thank you note
Thanks to my friend https://github.com/repnop for helping me understand
how to deal with function pointers in `unsafe` environments
Co-authored-by: Wesley Norris <repnop@repnop.dev>
# Objective
- Contributes to #16877
## Solution
- Initial creation of `bevy_platform_support` crate.
- Moved `bevy_utils::Instant` into new `bevy_platform_support` crate.
- Moved `portable-atomic`, `portable-atomic-util`, and
`critical-section` into new `bevy_platform_support` crate.
## Testing
- CI
---
## Showcase
Instead of needing code like this to import an `Arc`:
```rust
#[cfg(feature = "portable-atomic")]
use portable_atomic_util::Arc;
#[cfg(not(feature = "portable-atomic"))]
use alloc::sync::Arc;
```
We can now use:
```rust
use bevy_platform_support::sync::Arc;
```
This applies to many other types, but the goal is overall the same:
allowing crates to use `std`-like types without the boilerplate of
conditional compilation and platform-dependencies.
## Migration Guide
- Replace imports of `bevy_utils::Instant` with
`bevy_platform_support::time::Instant`
- Replace imports of `bevy::utils::Instant` with
`bevy::platform_support::time::Instant`
## Notes
- `bevy_platform_support` hasn't been reserved on `crates.io`
- ~~`bevy_platform_support` is not re-exported from `bevy` at this time.
It may be worthwhile exporting this crate, but I am unsure of a
reasonable name to export it under (`platform_support` may be a bit
wordy for user-facing).~~
- I've included an implementation of `Instant` which is suitable for
`no_std` platforms that are not Wasm for the sake of eliminating feature
gates around its use. It may be a controversial inclusion, so I'm happy
to remove it if required.
- There are many other items (`spin`, `bevy_utils::Sync(Unsafe)Cell`,
etc.) which should be added to this crate. I have kept the initial scope
small to demonstrate utility without making this too unwieldy.
---------
Co-authored-by: TimJentzsch <TimJentzsch@users.noreply.github.com>
Co-authored-by: Chris Russell <8494645+chescock@users.noreply.github.com>
Co-authored-by: François Mockers <francois.mockers@vleue.com>
