From 645b251f13640d9e3b04f6f1db368ff0469cd8b1 Mon Sep 17 00:00:00 2001
From: Tom Alexander <tom@fizz.buzz>
Date: Sun, 31 May 2020 13:52:20 -0400
Subject: [PATCH] Initial setup for a heterogenous tree of IntoContextElement.

---
 src/renderer/breadcrumb_tree.rs | 39 +++++++++++++++++++++++++++++++++
 src/renderer/mod.rs             |  1 +
 2 files changed, 40 insertions(+)
 create mode 100644 src/renderer/breadcrumb_tree.rs

diff --git a/src/renderer/breadcrumb_tree.rs b/src/renderer/breadcrumb_tree.rs
new file mode 100644
index 0000000..2402c2f
--- /dev/null
+++ b/src/renderer/breadcrumb_tree.rs
@@ -0,0 +1,39 @@
+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<dyn IntoContextElement + 'a>
+    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
+    }
+}
diff --git a/src/renderer/mod.rs b/src/renderer/mod.rs
index dfbbbe6..3439bc5 100644
--- a/src/renderer/mod.rs
+++ b/src/renderer/mod.rs
@@ -1,5 +1,6 @@
 //! This module contains a renderer for a rust implementation of LinkedIn Dust
 
+mod breadcrumb_tree;
 mod context_element;
 mod errors;
 mod inline_partial_tree;