ladybird/Libraries/LibHTML/TreeNode.h
Andreas Kling 7912592f89 LibHTML: Add inserted_into() and removed_from() TreeNode callbacks
These will be called when a Node or LayoutNode is inserted or removed
from a tree. They get the parent node as an argument.
2019-09-29 17:40:39 +02:00

83 lines
2.2 KiB
C++

#pragma once
#include <AK/Assertions.h>
#include <AK/NonnullRefPtr.h>
template<typename T>
class TreeNode {
public:
void ref()
{
ASSERT(m_ref_count);
++m_ref_count;
}
void deref()
{
ASSERT(m_ref_count);
if (!--m_ref_count)
delete static_cast<T*>(this);
}
int ref_count() const { return m_ref_count; }
T* parent() { return m_parent; }
const T* parent() const { return m_parent; }
bool has_children() const { return m_first_child; }
T* next_sibling() { return m_next_sibling; }
T* previous_sibling() { return m_previous_sibling; }
T* first_child() { return m_first_child; }
T* last_child() { return m_last_child; }
const T* next_sibling() const { return m_next_sibling; }
const T* previous_sibling() const { return m_previous_sibling; }
const T* first_child() const { return m_first_child; }
const T* last_child() const { return m_last_child; }
void append_child(NonnullRefPtr<T> node, bool call_inserted_into = true);
void donate_all_children_to(T& node);
protected:
TreeNode() { }
private:
int m_ref_count { 1 };
T* m_parent { nullptr };
T* m_first_child { nullptr };
T* m_last_child { nullptr };
T* m_next_sibling { nullptr };
T* m_previous_sibling { nullptr };
};
template<typename T>
inline void TreeNode<T>::append_child(NonnullRefPtr<T> node, bool call_inserted_into)
{
ASSERT(!node->m_parent);
if (m_last_child)
m_last_child->m_next_sibling = node.ptr();
node->m_previous_sibling = m_last_child;
node->m_parent = static_cast<T*>(this);
m_last_child = node.ptr();
if (!m_first_child)
m_first_child = m_last_child;
if (call_inserted_into)
node->inserted_into(static_cast<T&>(*this));
(void)node.leak_ref();
}
template<typename T>
inline void TreeNode<T>::donate_all_children_to(T& node)
{
for (T* child = m_first_child; child != nullptr;) {
T* next_child = child->m_next_sibling;
child->m_parent = nullptr;
child->m_next_sibling = nullptr;
child->m_previous_sibling = nullptr;
node.append_child(adopt(*child));
child = next_child;
}
m_first_child = nullptr;
m_last_child = nullptr;
}