Libraries: Move to Userland/Libraries/

Userland/Libraries/LibWeb/TreeNode.h

@@ -0,0 +1,443 @@
+/*
+ * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <AK/Assertions.h>
+#include <AK/NonnullRefPtr.h>
+#include <AK/TypeCasts.h>
+#include <AK/Weakable.h>
+#include <LibWeb/Forward.h>
+
+namespace Web {
+
+template<typename T>
+class TreeNode : public Weakable<T> {
+public:
+    void ref()
+    {
+        ASSERT(!m_in_removed_last_ref);
+        ASSERT(m_ref_count);
+        ++m_ref_count;
+    }
+
+    void unref()
+    {
+        ASSERT(!m_in_removed_last_ref);
+        ASSERT(m_ref_count);
+        if (!--m_ref_count) {
+            if constexpr (IsBaseOf<DOM::Node, T>::value) {
+                m_in_removed_last_ref = true;
+                static_cast<T*>(this)->removed_last_ref();
+            } else {
+                delete static_cast<T*>(this);
+            }
+            return;
+        }
+    }
+    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; }
+
+    int child_count() const
+    {
+        int count = 0;
+        for (auto* child = first_child(); child; child = child->next_sibling())
+            ++count;
+        return count;
+    }
+
+    T* child_at_index(int index)
+    {
+        int count = 0;
+        for (auto* child = first_child(); child; child = child->next_sibling()) {
+            if (count == index)
+                return child;
+            ++count;
+        }
+        return nullptr;
+    }
+
+    const T* child_at_index(int index) const
+    {
+        return const_cast<TreeNode*>(this)->child_at_index(index);
+    }
+
+    bool is_ancestor_of(const TreeNode&) const;
+
+    void prepend_child(NonnullRefPtr<T> node);
+    void append_child(NonnullRefPtr<T> node, bool notify = true);
+    void insert_before(NonnullRefPtr<T> node, RefPtr<T> child, bool notify = true);
+    NonnullRefPtr<T> remove_child(NonnullRefPtr<T> node);
+
+    void remove_all_children();
+
+    bool is_child_allowed(const T&) const { return true; }
+
+    T* next_in_pre_order()
+    {
+        if (first_child())
+            return first_child();
+        T* node;
+        if (!(node = next_sibling())) {
+            node = parent();
+            while (node && !node->next_sibling())
+                node = node->parent();
+            if (node)
+                node = node->next_sibling();
+        }
+        return node;
+    }
+
+    const T* next_in_pre_order() const
+    {
+        return const_cast<TreeNode*>(this)->next_in_pre_order();
+    }
+
+    bool is_before(const T& other) const
+    {
+        if (this == &other)
+            return false;
+        for (auto* node = this; node; node = node->next_in_pre_order()) {
+            if (node == &other)
+                return true;
+        }
+        return false;
+    }
+
+    template<typename Callback>
+    IterationDecision for_each_in_subtree(Callback callback) const
+    {
+        if (callback(static_cast<const T&>(*this)) == IterationDecision::Break)
+            return IterationDecision::Break;
+        for (auto* child = first_child(); child; child = child->next_sibling()) {
+            if (child->for_each_in_subtree(callback) == IterationDecision::Break)
+                return IterationDecision::Break;
+        }
+        return IterationDecision::Continue;
+    }
+
+    template<typename Callback>
+    IterationDecision for_each_in_subtree(Callback callback)
+    {
+        if (callback(static_cast<T&>(*this)) == IterationDecision::Break)
+            return IterationDecision::Break;
+        for (auto* child = first_child(); child; child = child->next_sibling()) {
+            if (child->for_each_in_subtree(callback) == IterationDecision::Break)
+                return IterationDecision::Break;
+        }
+        return IterationDecision::Continue;
+    }
+
+    template<typename U, typename Callback>
+    IterationDecision for_each_in_subtree_of_type(Callback callback)
+    {
+        if (is<U>(static_cast<const T&>(*this))) {
+            if (callback(static_cast<U&>(*this)) == IterationDecision::Break)
+                return IterationDecision::Break;
+        }
+        for (auto* child = first_child(); child; child = child->next_sibling()) {
+            if (child->template for_each_in_subtree_of_type<U>(callback) == IterationDecision::Break)
+                return IterationDecision::Break;
+        }
+        return IterationDecision::Continue;
+    }
+
+    template<typename U, typename Callback>
+    IterationDecision for_each_in_subtree_of_type(Callback callback) const
+    {
+        if (is<U>(static_cast<const T&>(*this))) {
+            if (callback(static_cast<const U&>(*this)) == IterationDecision::Break)
+                return IterationDecision::Break;
+        }
+        for (auto* child = first_child(); child; child = child->next_sibling()) {
+            if (child->template for_each_in_subtree_of_type<U>(callback) == IterationDecision::Break)
+                return IterationDecision::Break;
+        }
+        return IterationDecision::Continue;
+    }
+
+    template<typename Callback>
+    void for_each_child(Callback callback) const
+    {
+        return const_cast<TreeNode*>(this)->template for_each_child(move(callback));
+    }
+
+    template<typename Callback>
+    void for_each_child(Callback callback)
+    {
+        for (auto* node = first_child(); node; node = node->next_sibling())
+            callback(*node);
+    }
+
+    template<typename U, typename Callback>
+    void for_each_child_of_type(Callback callback)
+    {
+        for (auto* node = first_child(); node; node = node->next_sibling()) {
+            if (is<U>(node))
+                callback(downcast<U>(*node));
+        }
+    }
+
+    template<typename U, typename Callback>
+    void for_each_child_of_type(Callback callback) const
+    {
+        return const_cast<TreeNode*>(this)->template for_each_child_of_type<U>(move(callback));
+    }
+
+    template<typename U>
+    const U* next_sibling_of_type() const
+    {
+        return const_cast<TreeNode*>(this)->template next_sibling_of_type<U>();
+    }
+
+    template<typename U>
+    inline U* next_sibling_of_type()
+    {
+        for (auto* sibling = next_sibling(); sibling; sibling = sibling->next_sibling()) {
+            if (is<U>(*sibling))
+                return &downcast<U>(*sibling);
+        }
+        return nullptr;
+    }
+
+    template<typename U>
+    const U* previous_sibling_of_type() const
+    {
+        return const_cast<TreeNode*>(this)->template previous_sibling_of_type<U>();
+    }
+
+    template<typename U>
+    U* previous_sibling_of_type()
+    {
+        for (auto* sibling = previous_sibling(); sibling; sibling = sibling->previous_sibling()) {
+            if (is<U>(*sibling))
+                return &downcast<U>(*sibling);
+        }
+        return nullptr;
+    }
+
+    template<typename U>
+    const U* first_child_of_type() const
+    {
+        return const_cast<TreeNode*>(this)->template first_child_of_type<U>();
+    }
+
+    template<typename U>
+    const U* last_child_of_type() const
+    {
+        return const_cast<TreeNode*>(this)->template last_child_of_type<U>();
+    }
+
+    template<typename U>
+    U* first_child_of_type()
+    {
+        for (auto* child = first_child(); child; child = child->next_sibling()) {
+            if (is<U>(*child))
+                return &downcast<U>(*child);
+        }
+        return nullptr;
+    }
+
+    template<typename U>
+    U* last_child_of_type()
+    {
+        for (auto* child = last_child(); child; child = child->previous_sibling()) {
+            if (is<U>(*child))
+                return &downcast<U>(*child);
+        }
+        return nullptr;
+    }
+
+    template<typename U>
+    const U* first_ancestor_of_type() const
+    {
+        return const_cast<TreeNode*>(this)->template first_ancestor_of_type<U>();
+    }
+
+    template<typename U>
+    U* first_ancestor_of_type()
+    {
+        for (auto* ancestor = parent(); ancestor; ancestor = ancestor->parent()) {
+            if (is<U>(*ancestor))
+                return &downcast<U>(*ancestor);
+        }
+        return nullptr;
+    }
+
+protected:
+    TreeNode() { }
+
+    bool m_deletion_has_begun { false };
+    bool m_in_removed_last_ref { false };
+
+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>::remove_all_children()
+{
+    while (RefPtr<T> child = first_child())
+        remove_child(child.release_nonnull());
+}
+
+template<typename T>
+inline NonnullRefPtr<T> TreeNode<T>::remove_child(NonnullRefPtr<T> node)
+{
+    ASSERT(node->m_parent == this);
+
+    if (m_first_child == node)
+        m_first_child = node->m_next_sibling;
+
+    if (m_last_child == node)
+        m_last_child = node->m_previous_sibling;
+
+    if (node->m_next_sibling)
+        node->m_next_sibling->m_previous_sibling = node->m_previous_sibling;
+
+    if (node->m_previous_sibling)
+        node->m_previous_sibling->m_next_sibling = node->m_next_sibling;
+
+    node->m_next_sibling = nullptr;
+    node->m_previous_sibling = nullptr;
+    node->m_parent = nullptr;
+
+    node->removed_from(static_cast<T&>(*this));
+
+    node->unref();
+
+    static_cast<T*>(this)->children_changed();
+
+    return node;
+}
+
+template<typename T>
+inline void TreeNode<T>::append_child(NonnullRefPtr<T> node, bool notify)
+{
+    ASSERT(!node->m_parent);
+
+    if (!static_cast<T*>(this)->is_child_allowed(*node))
+        return;
+
+    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 (notify)
+        node->inserted_into(static_cast<T&>(*this));
+    [[maybe_unused]] auto& rc = node.leak_ref();
+
+    if (notify)
+        static_cast<T*>(this)->children_changed();
+}
+
+template<typename T>
+inline void TreeNode<T>::insert_before(NonnullRefPtr<T> node, RefPtr<T> child, bool notify)
+{
+    if (!child)
+        return append_child(move(node), notify);
+
+    ASSERT(!node->m_parent);
+    ASSERT(child->parent() == this);
+
+    if (!static_cast<T*>(this)->is_child_allowed(*node))
+        return;
+
+    node->m_previous_sibling = child->m_previous_sibling;
+    node->m_next_sibling = child;
+
+    if (child->m_previous_sibling)
+        child->m_previous_sibling->m_next_sibling = node;
+
+    if (m_first_child == child)
+        m_first_child = node;
+
+    child->m_previous_sibling = node;
+
+    if (m_first_child == child)
+        m_first_child = node;
+
+    node->m_parent = static_cast<T*>(this);
+    if (notify)
+        node->inserted_into(static_cast<T&>(*this));
+    [[maybe_unused]] auto& rc = node.leak_ref();
+
+    if (notify)
+        static_cast<T*>(this)->children_changed();
+}
+
+template<typename T>
+inline void TreeNode<T>::prepend_child(NonnullRefPtr<T> node)
+{
+    ASSERT(!node->m_parent);
+
+    if (!static_cast<T*>(this)->is_child_allowed(*node))
+        return;
+
+    if (m_first_child)
+        m_first_child->m_previous_sibling = node.ptr();
+    node->m_next_sibling = m_first_child;
+    node->m_parent = static_cast<T*>(this);
+    m_first_child = node.ptr();
+    if (!m_last_child)
+        m_last_child = m_first_child;
+    node->inserted_into(static_cast<T&>(*this));
+    [[maybe_unused]] auto& rc = node.leak_ref();
+
+    static_cast<T*>(this)->children_changed();
+}
+
+template<typename T>
+inline bool TreeNode<T>::is_ancestor_of(const TreeNode<T>& other) const
+{
+    for (auto* ancestor = other.parent(); ancestor; ancestor = ancestor->parent()) {
+        if (ancestor == this)
+            return true;
+    }
+    return false;
+}
+
+}