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/*
* Copyright (C) 2023 Igalia S.L. 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 APPLE INC. AND ITS 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 APPLE INC. OR ITS 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.
*/
#include "config.h"
#include "ContentVisibilityDocumentState.h"
#include "Element.h"
#include "IntersectionObserverCallback.h"
#include "IntersectionObserverEntry.h"
#include "NodeRenderStyle.h"
#include "RenderElement.h"
#include "RenderStyleInlines.h"
namespace WebCore {
class ContentVisibilityIntersectionObserverCallback final : public IntersectionObserverCallback {
public:
static Ref<ContentVisibilityIntersectionObserverCallback> create(Document& document)
{
return adoptRef(*new ContentVisibilityIntersectionObserverCallback(document));
}
private:
bool hasCallback() const final { return true; }
CallbackResult<void> handleEvent(IntersectionObserver&, const Vector<Ref<IntersectionObserverEntry>>& entries, IntersectionObserver&) final
{
ASSERT(!entries.isEmpty());
for (auto& entry : entries) {
if (auto* element = entry->target()) {
element->contentVisibilityViewportChange(entry->isIntersecting());
element->document().contentVisibilityDocumentState().updateOnScreenObservationTarget(*element, entry->isIntersecting());
}
}
return { };
}
ContentVisibilityIntersectionObserverCallback(Document& document)
: IntersectionObserverCallback(&document)
{
}
};
void ContentVisibilityDocumentState::observe(Element& element)
{
auto& state = element.document().contentVisibilityDocumentState();
if (auto* intersectionObserver = state.intersectionObserver(element.document()))
intersectionObserver->observe(element);
}
void ContentVisibilityDocumentState::unobserve(Element& element)
{
auto& state = element.document().contentVisibilityDocumentState();
if (auto& intersectionObserver = state.m_observer) {
intersectionObserver->unobserve(element);
state.updateOnScreenObservationTarget(element, false);
}
element.setContentRelevancyStatus({ });
}
IntersectionObserver* ContentVisibilityDocumentState::intersectionObserver(Document& document)
{
if (!m_observer) {
auto callback = ContentVisibilityIntersectionObserverCallback::create(document);
IntersectionObserver::Init options { &document, { }, { } };
auto observer = IntersectionObserver::create(document, WTFMove(callback), WTFMove(options));
if (observer.hasException())
return nullptr;
m_observer = observer.returnValue().ptr();
}
return m_observer.get();
}
bool ContentVisibilityDocumentState::updateRelevancyOfContentVisibilityElements(const OptionSet<ContentRelevancyStatus>& relevancyToCheck)
{
bool didUpdateAnyContentRelevancy = false;
for (auto target : m_observer->observationTargets()) {
if (target) {
auto oldRelevancy = target->contentRelevancyStatus();
auto newRelevancy = oldRelevancy;
auto setRelevancyValue = [&](ContentRelevancyStatus reason, bool value) {
if (value)
newRelevancy.add(reason);
else
newRelevancy.remove(reason);
};
if (relevancyToCheck.contains(ContentRelevancyStatus::OnScreen))
setRelevancyValue(ContentRelevancyStatus::OnScreen, m_onScreenObservationTargets.contains(*target));
if (relevancyToCheck.contains(ContentRelevancyStatus::Focused))
setRelevancyValue(ContentRelevancyStatus::Focused, target->hasFocusWithin());
auto hasTopLayerinSubtree = [](const Element& target) {
for (auto& element : target.document().topLayerElements()) {
if (element->isDescendantOf(target))
return true;
}
return false;
};
if (relevancyToCheck.contains(ContentRelevancyStatus::IsInTopLayer))
setRelevancyValue(ContentRelevancyStatus::IsInTopLayer, hasTopLayerinSubtree(*target));
if (oldRelevancy == newRelevancy)
continue;
target->setContentRelevancyStatus(newRelevancy);
target->invalidateStyle();
didUpdateAnyContentRelevancy = true;
}
}
return didUpdateAnyContentRelevancy;
}
// Workaround for lack of support for scroll anchoring. We make sure any content-visibility: auto elements
// above the one to be scrolled to are already hidden, so the scroll position will not need to be adjusted
// later.
// FIXME: remove when scroll anchoring is implemented.
void ContentVisibilityDocumentState::updateContentRelevancyStatusForScrollIfNeeded(const Element& scrollAnchor)
{
if (!m_observer)
return;
auto findSkippedContentRoot = [](const Element& element) -> const Element* {
const Element* found = nullptr;
if (element.renderer() && element.renderer()->isSkippedContent()) {
for (auto candidate = &element; candidate; candidate = candidate->parentElementInComposedTree()) {
if (candidate->renderer() && candidate->renderStyle()->contentVisibility() == ContentVisibility::Auto)
found = candidate;
}
}
return found;
};
if (auto* scrollAnchorRoot = findSkippedContentRoot(scrollAnchor)) {
for (auto target : m_observer->observationTargets()) {
if (target) {
ASSERT(target->renderer() && target->renderStyle()->contentVisibility() == ContentVisibility::Auto);
updateOnScreenObservationTarget(*target, false);
}
}
updateOnScreenObservationTarget(*scrollAnchorRoot, true);
scrollAnchorRoot->document().scheduleContentRelevancyUpdate(ContentRelevancyStatus::OnScreen);
scrollAnchorRoot->document().updateRelevancyOfContentVisibilityElements();
}
}
void ContentVisibilityDocumentState::updateOnScreenObservationTarget(const Element& element, bool onScreen)
{
if (onScreen)
m_onScreenObservationTargets.add(element);
else
m_onScreenObservationTargets.remove(element);
}
}
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