use crate::renderer::context_element::IntoContextElement; use std::borrow::Borrow; pub trait BreadcrumbTree { fn get_ice(&self) -> &dyn IntoContextElement; fn get_parent(&self) -> Option<&dyn BreadcrumbTree>; } struct BreadcrumbTreeNode<'a, C: IntoContextElement> { parent: Option<&'a dyn BreadcrumbTree>, element: BreadcrumbTreeNodeElement<'a, C>, } enum BreadcrumbTreeNodeElement<'a, C: IntoContextElement> { Owned(C), Borrowed(&'a C), } impl<'a, C: IntoContextElement> Borrow for BreadcrumbTreeNodeElement<'a, C> { fn borrow(&self) -> &(dyn IntoContextElement + 'a) { match self { BreadcrumbTreeNodeElement::Owned(ice) => ice, BreadcrumbTreeNodeElement::Borrowed(ice) => *ice, } } } impl<'a, C: IntoContextElement> BreadcrumbTree for BreadcrumbTreeNode<'a, C> { fn get_ice(&self) -> &dyn IntoContextElement { self.element.borrow() } fn get_parent(&self) -> Option<&dyn BreadcrumbTree> { self.parent } } struct BreadcrumbTreeIterator<'a>(Option<&'a dyn BreadcrumbTree>); impl<'a> Iterator for BreadcrumbTreeIterator<'a> { type Item = &'a dyn IntoContextElement; fn next(&mut self) -> Option { let ret = self.0; self.0 = self.0.map(|node| node.get_parent()).flatten(); ret.map(|node| node.get_ice()) } }