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LibHTML: Move selector matching into a SelectorEngine namespace

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This commit is contained in:
Andreas Kling 2019-10-08 15:33:58 +02:00
parent 06b6af61c6
commit 19dbfc3153
4 changed files with 78 additions and 59 deletions
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64
Libraries/LibHTML/CSS/SelectorEngine.cpp Normal file
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#include <LibHTML/CSS/SelectorEngine.h>
#include <LibHTML/DOM/Element.h>
namespace SelectorEngine {
bool matches(const Selector::Component& component, const Element& element)
{
switch (component.type) {
case Selector::Component::Type::Id:
return component.value == element.attribute("id");
case Selector::Component::Type::Class:
return element.has_class(component.value);
case Selector::Component::Type::TagName:
return component.value == element.tag_name();
default:
ASSERT_NOT_REACHED();
}
}
bool matches(const Selector& selector, int component_index, const Element& element)
{
auto& component = selector.components()[component_index];
if (!matches(component, element))
return false;
switch (component.relation) {
case Selector::Component::Relation::None:
return true;
case Selector::Component::Relation::Descendant:
ASSERT(component_index != 0);
for (auto* ancestor = element.parent(); ancestor; ancestor = ancestor->parent()) {
if (!is<Element>(*ancestor))
continue;
if (matches(selector, component_index - 1, to<Element>(*ancestor)))
return true;
}
return false;
case Selector::Component::Relation::ImmediateChild:
ASSERT(component_index != 0);
if (!element.parent() || !is<Element>(*element.parent()))
return false;
return matches(selector, component_index - 1, to<Element>(*element.parent()));
case Selector::Component::Relation::AdjacentSibling:
ASSERT(component_index != 0);
if (auto* sibling = element.previous_element_sibling())
return matches(selector, component_index - 1, *sibling);
return false;
case Selector::Component::Relation::GeneralSibling:
ASSERT(component_index != 0);
for (auto* sibling = element.previous_element_sibling(); sibling; sibling = sibling->previous_element_sibling()) {
if (matches(selector, component_index - 1, *sibling))
return true;
}
return false;
}
ASSERT_NOT_REACHED();
}
bool matches(const Selector& selector, const Element& element)
{
ASSERT(!selector.components().is_empty());
return matches(selector, selector.components().size() - 1, element);
}
}