portable-atomic 0.3.4

// Wrap the standard library's atomic types in newtype.
//
// This is not a reexport, because we want to backport changes like
// https://github.com/rust-lang/rust/pull/98383 to old compilers.

#[cfg_attr(portable_atomic_no_cfg_target_has_atomic, cfg(not(portable_atomic_no_atomic_cas)))]
#[cfg_attr(not(portable_atomic_no_cfg_target_has_atomic), cfg(target_has_atomic = "ptr"))]
use core::sync::atomic::Ordering;

#[repr(transparent)]
pub(crate) struct AtomicBool {
    inner: core::sync::atomic::AtomicBool,
}
impl AtomicBool {
    #[inline]
    pub(crate) const fn new(v: bool) -> Self {
        Self { inner: core::sync::atomic::AtomicBool::new(v) }
    }
    #[inline]
    pub(crate) fn is_lock_free() -> bool {
        Self::is_always_lock_free()
    }
    #[inline]
    pub(crate) const fn is_always_lock_free() -> bool {
        true
    }
    #[inline]
    pub(crate) fn into_inner(self) -> bool {
        self.inner.into_inner()
    }
    #[cfg_attr(portable_atomic_no_cfg_target_has_atomic, cfg(not(portable_atomic_no_atomic_cas)))]
    #[cfg_attr(not(portable_atomic_no_cfg_target_has_atomic), cfg(target_has_atomic = "ptr"))]
    #[inline]
    pub(crate) fn compare_exchange(
        &self,
        current: bool,
        new: bool,
        success: Ordering,
        failure: Ordering,
    ) -> Result<bool, bool> {
        // TODO: add cfg once https://github.com/rust-lang/rust/pull/98383 merged.
        let success = crate::utils::upgrade_success_ordering(success, failure);
        self.inner.compare_exchange(current, new, success, failure)
    }
    #[cfg_attr(portable_atomic_no_cfg_target_has_atomic, cfg(not(portable_atomic_no_atomic_cas)))]
    #[cfg_attr(not(portable_atomic_no_cfg_target_has_atomic), cfg(target_has_atomic = "ptr"))]
    #[inline]
    pub(crate) fn compare_exchange_weak(
        &self,
        current: bool,
        new: bool,
        success: Ordering,
        failure: Ordering,
    ) -> Result<bool, bool> {
        // TODO: add cfg once https://github.com/rust-lang/rust/pull/98383 merged.
        let success = crate::utils::upgrade_success_ordering(success, failure);
        self.inner.compare_exchange_weak(current, new, success, failure)
    }
}
impl core::ops::Deref for AtomicBool {
    type Target = core::sync::atomic::AtomicBool;
    #[inline]
    fn deref(&self) -> &Self::Target {
        &self.inner
    }
}
impl core::ops::DerefMut for AtomicBool {
    #[inline]
    fn deref_mut(&mut self) -> &mut Self::Target {
        &mut self.inner
    }
}

#[repr(transparent)]
pub(crate) struct AtomicPtr<T> {
    inner: core::sync::atomic::AtomicPtr<T>,
}
impl<T> AtomicPtr<T> {
    #[inline]
    pub(crate) const fn new(v: *mut T) -> Self {
        Self { inner: core::sync::atomic::AtomicPtr::new(v) }
    }
    #[inline]
    pub(crate) fn is_lock_free() -> bool {
        Self::is_always_lock_free()
    }
    #[inline]
    pub(crate) const fn is_always_lock_free() -> bool {
        true
    }
    #[inline]
    pub(crate) fn into_inner(self) -> *mut T {
        self.inner.into_inner()
    }
    #[cfg_attr(portable_atomic_no_cfg_target_has_atomic, cfg(not(portable_atomic_no_atomic_cas)))]
    #[cfg_attr(not(portable_atomic_no_cfg_target_has_atomic), cfg(target_has_atomic = "ptr"))]
    #[inline]
    pub(crate) fn compare_exchange(
        &self,
        current: *mut T,
        new: *mut T,
        success: Ordering,
        failure: Ordering,
    ) -> Result<*mut T, *mut T> {
        // TODO: add cfg once https://github.com/rust-lang/rust/pull/98383 merged.
        let success = crate::utils::upgrade_success_ordering(success, failure);
        self.inner.compare_exchange(current, new, success, failure)
    }
    #[cfg_attr(portable_atomic_no_cfg_target_has_atomic, cfg(not(portable_atomic_no_atomic_cas)))]
    #[cfg_attr(not(portable_atomic_no_cfg_target_has_atomic), cfg(target_has_atomic = "ptr"))]
    #[inline]
    pub(crate) fn compare_exchange_weak(
        &self,
        current: *mut T,
        new: *mut T,
        success: Ordering,
        failure: Ordering,
    ) -> Result<*mut T, *mut T> {
        // TODO: add cfg once https://github.com/rust-lang/rust/pull/98383 merged.
        let success = crate::utils::upgrade_success_ordering(success, failure);
        self.inner.compare_exchange_weak(current, new, success, failure)
    }
}
impl<T> core::ops::Deref for AtomicPtr<T> {
    type Target = core::sync::atomic::AtomicPtr<T>;
    #[inline]
    fn deref(&self) -> &Self::Target {
        &self.inner
    }
}
impl<T> core::ops::DerefMut for AtomicPtr<T> {
    #[inline]
    fn deref_mut(&mut self) -> &mut Self::Target {
        &mut self.inner
    }
}

macro_rules! atomic_int {
    ($($atomic_type:ident($int_type:ident)),*) => {$(
        #[repr(transparent)]
        pub(crate) struct $atomic_type {
            inner: core::sync::atomic::$atomic_type,
        }
        impl $atomic_type {
            #[inline]
            pub(crate) const fn new(v: $int_type) -> Self {
                Self { inner: core::sync::atomic::$atomic_type::new(v) }
            }
            #[inline]
            pub(crate) fn is_lock_free() -> bool {
                Self::is_always_lock_free()
            }
            #[inline]
            pub(crate) const fn is_always_lock_free() -> bool {
                true
            }
            #[inline]
            pub(crate) fn into_inner(self) -> $int_type {
                self.inner.into_inner()
            }
            #[cfg_attr(
                portable_atomic_no_cfg_target_has_atomic,
                cfg(not(portable_atomic_no_atomic_cas))
            )]
            #[cfg_attr(
                not(portable_atomic_no_cfg_target_has_atomic),
                cfg(target_has_atomic = "ptr")
            )]
            #[inline]
            pub(crate) fn compare_exchange(
                &self,
                current: $int_type,
                new: $int_type,
                success: Ordering,
                failure: Ordering,
            ) -> Result<$int_type, $int_type> {
                // TODO: add cfg once https://github.com/rust-lang/rust/pull/98383 merged.
                let success = crate::utils::upgrade_success_ordering(success, failure);
                self.inner.compare_exchange(current, new, success, failure)
            }
            #[cfg_attr(
                portable_atomic_no_cfg_target_has_atomic,
                cfg(not(portable_atomic_no_atomic_cas))
            )]
            #[cfg_attr(
                not(portable_atomic_no_cfg_target_has_atomic),
                cfg(target_has_atomic = "ptr")
            )]
            #[inline]
            pub(crate) fn compare_exchange_weak(
                &self,
                current: $int_type,
                new: $int_type,
                success: Ordering,
                failure: Ordering,
            ) -> Result<$int_type, $int_type> {
                // TODO: add cfg once https://github.com/rust-lang/rust/pull/98383 merged.
                let success = crate::utils::upgrade_success_ordering(success, failure);
                self.inner.compare_exchange_weak(current, new, success, failure)
            }
            #[cfg(portable_atomic_no_atomic_min_max)]
            #[cfg_attr(
                portable_atomic_no_cfg_target_has_atomic,
                cfg(not(portable_atomic_no_atomic_cas))
            )]
            #[cfg_attr(
                not(portable_atomic_no_cfg_target_has_atomic),
                cfg(target_has_atomic = "ptr")
            )]
            #[inline]
            fn fetch_update<F>(
                &self,
                set_order: Ordering,
                fetch_order: Ordering,
                mut f: F,
            ) -> Result<$int_type, $int_type>
            where
                F: FnMut($int_type) -> Option<$int_type>,
            {
                let mut prev = self.load(fetch_order);
                while let Some(next) = f(prev) {
                    match self.compare_exchange_weak(prev, next, set_order, fetch_order) {
                        x @ Ok(_) => return x,
                        Err(next_prev) => prev = next_prev,
                    }
                }
                Err(prev)
            }
            #[cfg_attr(
                portable_atomic_no_cfg_target_has_atomic,
                cfg(not(portable_atomic_no_atomic_cas))
            )]
            #[cfg_attr(
                not(portable_atomic_no_cfg_target_has_atomic),
                cfg(target_has_atomic = "ptr")
            )]
            #[inline]
            pub(crate) fn fetch_max(&self, val: $int_type, order: Ordering) -> $int_type {
                #[cfg(not(portable_atomic_no_atomic_min_max))]
                {
                    #[cfg(any(
                        all(
                            target_arch = "aarch64",
                            any(target_feature = "lse", portable_atomic_target_feature = "lse"),
                        ),
                        portable_atomic_armv5te,
                        target_arch = "mips",
                        target_arch = "mips64",
                        target_arch = "powerpc",
                        target_arch = "powerpc64",
                    ))]
                    {
                        // HACK: the following operations are currently broken (at least on qemu):
                        // - aarch64's `AtomicI{8,16}::fetch_{max,min}` (release mode + lse)
                        // - armv5te's `Atomic{I,U}{8,16}::fetch_{max,min}`
                        // - mips's `AtomicI8::fetch_{max,min}` (release mode)
                        // - mipsel's `AtomicI{8,16}::fetch_{max,min}` (debug mode, at least)
                        // - mips64's `AtomicI8::fetch_{max,min}` (release mode)
                        // - mips64el's `AtomicI{8,16}::fetch_{max,min}` (debug mode, at least)
                        // - powerpc's `AtomicI{8,16}::fetch_{max,min}`
                        // - powerpc64's `AtomicI{8,16}::fetch_{max,min}` (debug mode, at least)
                        // - powerpc64le's `AtomicU{8,16}::fetch_{max,min}` (release mode + fat LTO)
                        // See also https://github.com/taiki-e/portable-atomic/issues/2
                        if core::mem::size_of::<$int_type>() <= 2 {
                            return self
                                .fetch_update(
                                    order,
                                    crate::utils::strongest_failure_ordering(order),
                                    |x| Some(core::cmp::max(x, val)),
                                )
                                .unwrap();
                        }
                    }
                    self.inner.fetch_max(val, order)
                }
                #[cfg(portable_atomic_no_atomic_min_max)]
                {
                    self.fetch_update(order, crate::utils::strongest_failure_ordering(order), |x| {
                        Some(core::cmp::max(x, val))
                    })
                    .unwrap()
                }
            }
            #[cfg_attr(
                portable_atomic_no_cfg_target_has_atomic,
                cfg(not(portable_atomic_no_atomic_cas))
            )]
            #[cfg_attr(
                not(portable_atomic_no_cfg_target_has_atomic),
                cfg(target_has_atomic = "ptr")
            )]
            #[inline]
            pub(crate) fn fetch_min(&self, val: $int_type, order: Ordering) -> $int_type {
                #[cfg(not(portable_atomic_no_atomic_min_max))]
                {
                    #[cfg(any(
                        all(
                            target_arch = "aarch64",
                            any(target_feature = "lse", portable_atomic_target_feature = "lse"),
                        ),
                        portable_atomic_armv5te,
                        target_arch = "mips",
                        target_arch = "mips64",
                        target_arch = "powerpc",
                        target_arch = "powerpc64",
                    ))]
                    {
                        // HACK: the following operations are currently broken (at least on qemu):
                        // - aarch64's `AtomicI{8,16}::fetch_{max,min}` (release mode + lse)
                        // - armv5te's `Atomic{I,U}{8,16}::fetch_{max,min}`
                        // - mips's `AtomicI8::fetch_{max,min}` (release mode)
                        // - mipsel's `AtomicI{8,16}::fetch_{max,min}` (debug mode, at least)
                        // - mips64's `AtomicI8::fetch_{max,min}` (release mode)
                        // - mips64el's `AtomicI{8,16}::fetch_{max,min}` (debug mode, at least)
                        // - powerpc's `AtomicI{8,16}::fetch_{max,min}`
                        // - powerpc64's `AtomicI{8,16}::fetch_{max,min}` (debug mode, at least)
                        // - powerpc64le's `AtomicU{8,16}::fetch_{max,min}` (release mode + fat LTO)
                        // See also https://github.com/taiki-e/portable-atomic/issues/2
                        if core::mem::size_of::<$int_type>() <= 2 {
                            return self
                                .fetch_update(
                                    order,
                                    crate::utils::strongest_failure_ordering(order),
                                    |x| Some(core::cmp::min(x, val)),
                                )
                                .unwrap();
                        }
                    }
                    self.inner.fetch_min(val, order)
                }
                #[cfg(portable_atomic_no_atomic_min_max)]
                {
                    self.fetch_update(order, crate::utils::strongest_failure_ordering(order), |x| {
                        Some(core::cmp::min(x, val))
                    })
                    .unwrap()
                }
            }
        }
        impl core::ops::Deref for $atomic_type {
            type Target = core::sync::atomic::$atomic_type;
            #[inline]
            fn deref(&self) -> &Self::Target {
                &self.inner
            }
        }
        impl core::ops::DerefMut for $atomic_type {
            #[inline]
            fn deref_mut(&mut self) -> &mut Self::Target {
                &mut self.inner
            }
        }
    )*};
}

atomic_int!(AtomicIsize(isize), AtomicUsize(usize));
atomic_int!(AtomicI8(i8), AtomicI16(i16), AtomicU8(u8), AtomicU16(u16));
#[cfg(not(target_pointer_width = "16"))] // cfg(target_has_atomic_load_store = "32")
atomic_int!(AtomicI32(i32), AtomicU32(u32));
#[cfg_attr(portable_atomic_no_cfg_target_has_atomic, cfg(not(portable_atomic_no_atomic_64)))]
#[cfg_attr(
    not(portable_atomic_no_cfg_target_has_atomic),
    cfg(any(target_has_atomic = "64", target_pointer_width = "64")) // cfg(target_has_atomic_load_store = "64")
)]
atomic_int!(AtomicI64(i64), AtomicU64(u64));