devela 0.27.0

A development layer of coherence.
Documentation 
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// devela::data::id::uid::pin
//
//! Defines [`IdPin`].
//
// [A physically anchored identity]

use crate::Pin;

#[doc = crate::_tags!(uid allocation)]
/// A unique identifier based on a pinned stack-allocated reference.
#[doc = crate::_doc_location!("data/id")]
///
/// `IdPin` generates a unique ID by pinning a value on the stack,
/// ensuring that the ID is based on the stack memory address
/// for the lifetime of the reference.
///
/// It doesn't implement `Clone` or `Default`.
///
// #[cfg_attr(feature = "alloc", doc = "See also [`IdPinBox`].")]
///
/// # Example
/// ```
/// # use devela::IdPin;
/// let mut data1: u8 = 0;
/// let id1 = IdPin::new(&mut data1);
/// ```
///
#[doc = crate::_doc!(vendor: "object-id")]
pub struct IdPin<'a> {
    inner: Pin<&'a mut u8>,
}

impl<'a> IdPin<'a> {
    /// Creates a new `IdPin` with a unique stack memory address.
    ///
    /// Expects a mutable reference to a `u8` `data` that will be pinned.
    pub fn new(data: &'a mut u8) -> Self {
        let inner = Pin::new(data);
        Self { inner }
    }

    /// Returns the unique ID as a `usize`, derived from the stack memory address.
    pub fn as_usize(&self) -> usize {
        (&raw const *self.inner).addr()
    }
}

mod impl_traits {
    use crate::{IdPin, Ordering, Ptr, impl_trait};

    impl_trait![fmt::Debug for IdPin['a]['a] |self, f| write!(f, "{}", self.as_usize())];
    impl_trait![Hash for IdPin['a]['a] |self, s| self.as_usize().hash(s)];

    impl Eq for IdPin<'_> {}
    impl PartialEq for IdPin<'_> {
        fn eq(&self, other: &Self) -> bool {
            Ptr::eq(&*self.inner, &*other.inner)
        }
    }

    impl PartialOrd for IdPin<'_> {
        fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
            Some(self.cmp(other))
        }
    }
    impl Ord for IdPin<'_> {
        fn cmp(&self, other: &Self) -> Ordering {
            self.as_usize().cmp(&other.as_usize())
        }
    }
}