Merge branch '💥-zeroable' into 🦆

Author: yvt

Cargo.lock

@@ -62,7 +62,7 @@ pub use r3_core::{bag, hunk, kernel, time};
 ///
 /// [1]: r3_core#stability
 pub mod utils {
-    pub use r3_core::utils::{Init, ZeroInit};
+    pub use r3_core::utils::{Init, Zeroable, ZeroableInOption};
 }
 
 /// The prelude module.

src/r3/src/lib.rs

@@ -7,6 +7,19 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 ## [Unreleased]
 
+### Changed
+
+- **Breaking:** `{Bind,Hunk}Definer::zeroed` now requires `T: Zeroable` instead of `T: ZeroInit`.
+
+### Added
+
+- `r3_core::utils::{Zeroable,ZeroableInOption}` (re-exported from `bytemuck ^1`)
+- Implement `Zeroable` on `r3_core::time::{Duration, Time}`
+
+### Removed
+
+- **Breaking:** `r3_core::utils::ZeroInit` (superseded by `Zeroable`)
+
 ## [0.1.4] - 2022-11-16
 
 ### Changed

src/r3_core/CHANGELOG.md

@@ -28,6 +28,7 @@ seq-macro = { version = "0.3.0" }
 svgbobdoc = { version = "0.3.0" }
 tokenlock = { version = "0.3.4", default-features = false }
 arrayvec = { version = "0.7.1", default-features = false }
+bytemuck = { version = "1.12.3", features = ["derive"] }
 bitflags = { version = "1.2.1" }
 macropol = { version = "0.1.2" }
 either = { version = "1.6.1", default-features = false }

src/r3_core/Cargo.toml

@@ -172,7 +172,7 @@ use crate::{
     closure::Closure,
     hunk::Hunk,
     kernel::{self, cfg, prelude::*, raw, raw_cfg, StartupHook},
-    utils::{refcell::RefCell, ComptimeVec, ConstAllocator, Init, PhantomInvariant, ZeroInit},
+    utils::{refcell::RefCell, ComptimeVec, ConstAllocator, Init, PhantomInvariant, Zeroable},
 };
 
 mod sorter;
@@ -213,8 +213,10 @@ impl<T> BindData<T> {
     }
 }
 
+// FIXME: Derive this when <https://github.com/Lokathor/bytemuck/pull/148> is
+//        merged
 // Safety: Zero-initialization is valid for `MaybeUninit`
-unsafe impl<T> ZeroInit for BindData<T> {}
+unsafe impl<T> Zeroable for BindData<T> {}
 
 // Main configuration interface
 // ----------------------------------------------------------------------------
@@ -466,8 +468,8 @@ impl<System>
     }
 
     /// Zero-initialize the binding contents.
-    pub const fn zeroed<T: ZeroInit>(self) -> BindDefiner<System, (), FnBindNever<T>> {
-        // Safety: `T: ZeroInit` means it's safe to zero-initialize
+    pub const fn zeroed<T: Zeroable>(self) -> BindDefiner<System, (), FnBindNever<T>> {
+        // Safety: `T: Zeroable` means it's safe to zero-initialize
         unsafe { self.zeroed_unchecked() }
     }
 

src/r3_core/src/bind.rs

@@ -9,7 +9,7 @@ use core::{
 
 use crate::{
     kernel::{self, cfg, hunk, raw, raw_cfg, Cfg, StartupHook},
-    utils::{Init, ZeroInit},
+    utils::{Init, Zeroable},
 };
 
 /// The priority of the [startup hooks] used to initialize [typed hunks]. It has
@@ -123,9 +123,9 @@ impl<System: raw::KernelBase + cfg::KernelStatic, T: ?Sized, InitTag>
     /// Zero-initialize the hunk.
     pub const fn zeroed(self) -> HunkDefiner<System, T, ZeroInitTag>
     where
-        T: ZeroInit,
+        T: Zeroable,
     {
-        // Safety: `T: ZeroInit`, so it's zero-initializable
+        // Safety: `T: Zeroable`, so it's zero-initializable
         unsafe { self.zeroed_unchecked() }
     }
 

src/r3_core/src/hunk.rs

@@ -1,12 +1,12 @@
 use core::{fmt, ops};
 
-use crate::utils::{Init, ZeroInit};
+use crate::utils::{Init, Zeroable};
 
 /// Represents a signed time span used by the API surface of R3-OS.
 ///
 /// `Duration` is backed by `i32` and can represent the range
 /// [-35′47.483648″, +35′47.483647″] with microsecond precision.
-#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Zeroable)]
 #[repr(transparent)]
 pub struct Duration {
     micros: i32,
@@ -16,10 +16,6 @@ impl Init for Duration {
     const INIT: Self = Self::ZERO;
 }
 
-// Safety: `Duration` is `repr(transparent)` and the only inner field is `i32`,
-//         which is `ZeroInit`
-unsafe impl ZeroInit for Duration {}
-
 impl Default for Duration {
     fn default() -> Self {
         Self::INIT

src/r3_core/src/time/duration.rs

@@ -2,7 +2,7 @@ use core::{fmt, ops};
 
 use crate::{
     time::Duration,
-    utils::{Init, ZeroInit},
+    utils::{Init, Zeroable},
 };
 
 /// Represents a timestamp used by the API surface of R3-OS.
@@ -13,7 +13,7 @@ use crate::{
 ///
 /// `Time` is backed by `u64` and can represent up to 213,503,982 days with
 /// microsecond precision.
-#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Zeroable)]
 #[repr(transparent)]
 pub struct Time {
     micros: u64,
@@ -23,10 +23,6 @@ impl Init for Time {
     const INIT: Self = Self::ZERO;
 }
 
-// Safety: `Time` is `repr(transparent)` and the only inner field is `u64`,
-//         which is `ZeroInit`
-unsafe impl ZeroInit for Time {}
-
 impl Default for Time {
     fn default() -> Self {
         Self::INIT

src/r3_core/src/time/time.rs

@@ -3,7 +3,16 @@
 //! **This module is exempt from [the API stability guarantee][1]** unless
 //! specified otherwise. It's exposed mostly because it's needed by macros.
 //!
+//! # Re-exports
+//!
+//! - [`Zeroable`], [`ZeroableInOption`]: Re-exported from [`bytemuck`]` ^1`.
+//!   `Zeroable` is a marker trait used in [`HunkDefiner::zeroed`][2] and
+//!   suchlike. It can be derived for struct types.
+//!   These re-exports are subject to the application-side API stability
+//!   guarantee.
+//!
 //! [1]: crate#stability
+//! [2]: crate::hunk::HunkDefiner::zeroed
 use core::marker::PhantomData;
 
 /// Conditional type
@@ -65,11 +74,11 @@ mod init;
 pub mod mem;
 mod rawcell;
 pub(crate) mod refcell;
-mod zeroinit;
 pub use aligned_storage::*;
 pub use init::*;
 pub use rawcell::*;
-pub use zeroinit::*;
+
+pub use bytemuck::{Zeroable, ZeroableInOption};
 
 /// A phantom type that is invariant over `T`.
 pub type PhantomInvariant<T> = core::marker::PhantomData<fn(T) -> T>;

src/r3_core/src/utils/mod.rs

@@ -1,6 +1,6 @@
 use core::cell::UnsafeCell;
 
-use crate::utils::{Init, ZeroInit};
+use crate::utils::{Init, Zeroable};
 
 /// Like `UnsafeCell`, but implements `Sync`.
 #[derive(Debug)]
@@ -28,4 +28,6 @@ impl<T: ?Sized> RawCell<T> {
 impl<T: Init> Init for RawCell<T> {
     const INIT: Self = RawCell::new(T::INIT);
 }
-unsafe impl<T: ZeroInit> ZeroInit for RawCell<T> {}
+// FIXME: Derive this when <https://github.com/Lokathor/bytemuck/pull/148> is
+//        merged
+unsafe impl<T: Zeroable> Zeroable for RawCell<T> {}