pub trait Node {
type Key;
fn prev(&self) -> Option<&Self::Key>;
fn next(&self) -> Option<&Self::Key>;
fn prev_mut<T: NodeToken>(&mut self) -> &mut Option<Self::Key>;
fn next_mut<T: NodeToken>(&mut self) -> &mut Option<Self::Key>;
}
#[macro_export]
macro_rules! impl_node {
(
$node:ident$(<$($g:tt),* $(,)?>)?
{ Key = $key:ty, prev = $prev:ident, next = $next:ident $(,)? }
) => {
impl$(<$($g),*>)? $crate::Node for $node$(<$($g),*>)? {
type Key = $key;
#[inline]
fn prev(&self) -> Option<&Self::Key> {
self.$prev.as_ref()
}
#[inline]
fn next(&self) -> Option<&Self::Key> {
self.$next.as_ref()
}
#[inline]
fn prev_mut<__: $crate::NodeToken>(&mut self) -> &mut Option<Self::Key> {
&mut self.$prev
}
#[inline]
fn next_mut<__: $crate::NodeToken>(&mut self) -> &mut Option<Self::Key> {
&mut self.$next
}
}
};
}
#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub struct ValueNode<K, V> {
value: V,
prev: Option<K>,
next: Option<K>,
}
impl_node!(ValueNode<K, V> { Key = K, prev = prev, next = next});
impl<K, V> ValueNode<K, V> {
pub fn new(value: V) -> Self {
Self {
value,
prev: None,
next: None,
}
}
pub fn into_value(self) -> V {
self.value
}
pub fn value(&self) -> &V {
&self.value
}
pub fn value_mut(&mut self) -> &mut V {
&mut self.value
}
}
impl<K, V> Default for ValueNode<K, V>
where
V: Default,
{
fn default() -> Self {
Self::new(V::default())
}
}
impl<K, V> From<V> for ValueNode<K, V> {
fn from(value: V) -> Self {
Self::new(value)
}
}
pub trait NodeToken: private::Sealed {}
pub(crate) struct Token;
impl NodeToken for Token {}
impl private::Sealed for Token {}
mod private {
pub trait Sealed {}
}