From 2305dee455874ee08c6e77df83132a3bd314c858 Mon Sep 17 00:00:00 2001
From: Andreas Kling <awesomekling@gmail.com>
Date: Fri, 18 Oct 2019 10:16:33 +0200
Subject: [PATCH] LibHTML: Add LayoutNode::first_ancestor_of_type<T>()

---
 Libraries/LibHTML/Layout/LayoutNode.h | 32 +++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/Libraries/LibHTML/Layout/LayoutNode.h b/Libraries/LibHTML/Layout/LayoutNode.h
index e515de53d2..0fc8f38ca7 100644
--- a/Libraries/LibHTML/Layout/LayoutNode.h
+++ b/Libraries/LibHTML/Layout/LayoutNode.h
@@ -67,6 +67,7 @@ public:
 
     const StyleProperties& style() const;
 
+    LayoutNodeWithStyle* parent();
     const LayoutNodeWithStyle* parent() const;
 
     void inserted_into(LayoutNode&) {}
@@ -97,6 +98,12 @@ public:
     template<typename T>
     T* first_child_of_type();
 
+    template<typename T>
+    const T* first_ancestor_of_type() const;
+
+    template<typename T>
+    T* first_ancestor_of_type();
+
 protected:
     explicit LayoutNode(const Node*);
 
@@ -157,6 +164,11 @@ inline const LayoutNodeWithStyle* LayoutNode::parent() const
     return static_cast<const LayoutNodeWithStyle*>(TreeNode<LayoutNode>::parent());
 }
 
+inline LayoutNodeWithStyle* LayoutNode::parent()
+{
+    return static_cast<LayoutNodeWithStyle*>(TreeNode<LayoutNode>::parent());
+}
+
 template<typename T>
 inline bool is(const LayoutNode&)
 {
@@ -248,3 +260,23 @@ inline T* LayoutNode::first_child_of_type()
     }
     return nullptr;
 }
+
+template<typename T>
+inline const T* LayoutNode::first_ancestor_of_type() const
+{
+    for (auto* ancestor = parent(); ancestor; ancestor = ancestor->parent()) {
+        if (is<T>(*ancestor))
+            return &to<T>(*ancestor);
+    }
+    return nullptr;
+}
+
+template<typename T>
+inline T* LayoutNode::first_ancestor_of_type()
+{
+    for (auto* ancestor = parent(); ancestor; ancestor = ancestor->parent()) {
+        if (is<T>(*ancestor))
+            return &to<T>(*ancestor);
+    }
+    return nullptr;
+}