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LibHTML: Add TreeNode::for_each_in_subtree_of_type<T>()

This allows you to iterate a subtree and get a callback for every node
where is<T>(node) == true. This makes for quite pleasant DOM traversal.
This commit is contained in:
Andreas Kling 2019-12-18 21:34:03 +01:00
parent 54bd322881
commit 1aea8f116b
5 changed files with 56 additions and 25 deletions

View file

@ -177,9 +177,9 @@ void Document::layout()
void Document::update_style() void Document::update_style()
{ {
for_each_in_subtree([&](Node& node) { for_each_in_subtree_of_type<Element>([&](auto& element) {
if (node.needs_style_update()) if (element.needs_style_update())
to<Element>(node).recompute_style(); element.recompute_style();
return IterationDecision::Continue; return IterationDecision::Continue;
}); });
update_layout(); update_layout();
@ -252,23 +252,23 @@ void Document::set_hovered_node(Node* node)
const Element* Document::get_element_by_id(const String& id) const const Element* Document::get_element_by_id(const String& id) const
{ {
const Element* element = nullptr; const Element* found_element = nullptr;
for_each_in_subtree([&](auto& node) { for_each_in_subtree_of_type<Element>([&](auto& element) {
if (is<Element>(node) && to<Element>(node).attribute("id") == id) { if (element.attribute("id") == id) {
element = &to<Element>(node); found_element = &element;
return IterationDecision::Break; return IterationDecision::Break;
} }
return IterationDecision::Continue; return IterationDecision::Continue;
}); });
return element; return found_element;
} }
Vector<const Element*> Document::get_elements_by_name(const String& name) const Vector<const Element*> Document::get_elements_by_name(const String& name) const
{ {
Vector<const Element*> elements; Vector<const Element*> elements;
for_each_in_subtree([&](auto& node) { for_each_in_subtree_of_type<Element>([&](auto& element) {
if (is<Element>(node) && to<Element>(node).attribute("name") == name) if (element.attribute("name") == name)
elements.append(&to<Element>(node)); elements.append(&element);
return IterationDecision::Continue; return IterationDecision::Continue;
}); });
return elements; return elements;

View file

@ -34,12 +34,10 @@ void HTMLFormElement::submit()
Vector<NameAndValue> parameters; Vector<NameAndValue> parameters;
for_each_in_subtree([&](auto& node) { for_each_in_subtree_of_type<HTMLInputElement>([&](auto& node) {
if (is<HTMLInputElement>(node)) {
auto& input = to<HTMLInputElement>(node); auto& input = to<HTMLInputElement>(node);
if (!input.name().is_null()) if (!input.name().is_null())
parameters.append({ input.name(), input.value() }); parameters.append({ input.name(), input.value() });
}
return IterationDecision::Continue; return IterationDecision::Continue;
}); });

View file

@ -74,9 +74,8 @@ RefPtr<LayoutNode> Node::create_layout_node(const StyleProperties*) const
void Node::invalidate_style() void Node::invalidate_style()
{ {
for_each_in_subtree([&](auto& node) { for_each_in_subtree_of_type<Element>([&](auto& element) {
if (is<Element>(node)) element.set_needs_style_update(true);
node.set_needs_style_update(true);
return IterationDecision::Continue; return IterationDecision::Continue;
}); });
document().schedule_style_update(); document().schedule_style_update();

View file

@ -34,11 +34,8 @@ void LayoutDocument::layout()
void LayoutDocument::did_set_viewport_rect(Badge<Frame>, const Rect& a_viewport_rect) void LayoutDocument::did_set_viewport_rect(Badge<Frame>, const Rect& a_viewport_rect)
{ {
FloatRect viewport_rect(a_viewport_rect.x(), a_viewport_rect.y(), a_viewport_rect.width(), a_viewport_rect.height()); FloatRect viewport_rect(a_viewport_rect.x(), a_viewport_rect.y(), a_viewport_rect.width(), a_viewport_rect.height());
for_each_in_subtree([&](auto& layout_node) { for_each_in_subtree_of_type<LayoutImage>([&](auto& layout_image) {
if (is<LayoutImage>(layout_node)) { const_cast<HTMLImageElement&>(layout_image.node()).set_volatile({}, !viewport_rect.intersects(layout_image.rect()));
auto& image = to<LayoutImage>(layout_node);
const_cast<HTMLImageElement&>(image.node()).set_volatile({}, !viewport_rect.intersects(image.rect()));
}
return IterationDecision::Continue; return IterationDecision::Continue;
}); });
} }

View file

@ -4,6 +4,15 @@
#include <AK/NonnullRefPtr.h> #include <AK/NonnullRefPtr.h>
#include <AK/Weakable.h> #include <AK/Weakable.h>
// FIXME: I wish I didn't have to forward declare these, but I can't seem to avoid
// it if I still want to have for_each_in_subtree_of_type<U> inline here.
class Node;
class LayoutNode;
template<typename T>
bool is(const Node&);
template<typename T>
bool is(const LayoutNode&);
template<typename T> template<typename T>
class TreeNode : public Weakable<T> { class TreeNode : public Weakable<T> {
public: public:
@ -122,6 +131,34 @@ public:
return IterationDecision::Continue; 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;
}
protected: protected:
TreeNode() {} TreeNode() {}