x-bow 0.2.0

Precise State Management Library
Documentation 
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use std::cell::{Ref, RefMut};

use crate::{borrow_mut_guard::BorrowMutGuard, path_ext::PathExt, Path};

/// Implemented for [Path] objects that will always be able to obtain their
/// data piece.
///
/// Such paths are those that
/// *   don't go through any `enum` (if the enum is in a different variant,
///     then the data cannot be obtained)
/// *   don't go through `Vec` or `HashMap` (the requested item might not
///     be in the collection)
///
/// The methods in this trait are similar to the borrow methods in [PathExt],
/// but they don't return [Option] because we know the data is always there.
pub trait PathExtGuaranteed: PathExt {
    /// Borrow the data at this path immutably.
    ///
    /// See [borrow_opt][PathExt::borrow_opt] for more details.
    fn borrow(&self) -> Ref<'_, <Self as Path>::Out> {
        self.borrow_opt().unwrap()
    }
    /// Borrow the data at this path mutably, notifying all the relevant
    /// change listeners when the returned borrow guard is dropped.
    ///
    /// See [borrow_opt_mut][PathExt::borrow_opt_mut] for more details.
    fn borrow_mut(&self) -> BorrowMutGuard<'_, Self> {
        self.borrow_opt_mut().unwrap()
    }

    /// Borrow the data at this path mutably **without notifying** any listener.
    ///
    /// See [borrow_opt_mut_without_notifying][PathExt::borrow_opt_mut_without_notifying]
    /// for more details.
    fn borrow_mut_without_notifying(&self) -> RefMut<'_, <Self as Path>::Out> {
        self.borrow_opt_mut_without_notifying().unwrap()
    }

    /// Clone the data identified by this path.
    ///
    /// Equivalent to `path.borrow().clone()`.
    fn get(&self) -> Self::Out
    where
        Self::Out: Clone,
    {
        self.borrow().clone()
    }

    /// Set the data identified by this path, notifying listeners.
    ///
    /// Equivalent to `*path.borrow_mut() = data;`
    fn set(&self, data: Self::Out)
    where
        Self::Out: Sized,
    {
        *self.borrow_mut() = data;
    }
}