104 lines
3.7 KiB
C++
104 lines
3.7 KiB
C++
/*
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* Copyright (C) 2020 Igalia S.L.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
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* THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "config.h"
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#include "LazyLoadImageObserver.h"
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#include "Frame.h"
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#include "HTMLImageElement.h"
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#include "IntersectionObserverCallback.h"
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#include "RenderStyle.h"
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#include <limits>
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namespace WebCore {
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class LazyImageLoadIntersectionObserverCallback final : public IntersectionObserverCallback {
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public:
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static Ref<LazyImageLoadIntersectionObserverCallback> create(Document& document)
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{
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return adoptRef(*new LazyImageLoadIntersectionObserverCallback(document));
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}
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private:
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bool hasCallback() const final { return true; }
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CallbackResult<void> handleEvent(IntersectionObserver&, const Vector<Ref<IntersectionObserverEntry>>& entries, IntersectionObserver&) final
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{
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ASSERT(!entries.isEmpty());
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for (auto& entry : entries) {
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if (!entry->isIntersecting())
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continue;
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auto* element = entry->target();
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if (is<HTMLImageElement>(element)) {
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downcast<HTMLImageElement>(*element).loadDeferredImage();
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element->document().lazyLoadImageObserver().unobserve(*element, element->document());
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}
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}
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return { };
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}
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LazyImageLoadIntersectionObserverCallback(Document& document)
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: IntersectionObserverCallback(&document)
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{
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}
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};
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void LazyLoadImageObserver::observe(Element& element)
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{
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auto& observer = element.document().lazyLoadImageObserver();
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auto* intersectionObserver = observer.intersectionObserver(element.document());
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if (!intersectionObserver)
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return;
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intersectionObserver->observe(element);
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}
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void LazyLoadImageObserver::unobserve(Element& element, Document& document)
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{
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if (auto& observer = document.lazyLoadImageObserver().m_observer)
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observer->unobserve(element);
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}
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IntersectionObserver* LazyLoadImageObserver::intersectionObserver(Document& document)
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{
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if (!m_observer) {
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auto callback = LazyImageLoadIntersectionObserverCallback::create(document);
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IntersectionObserver::Init options { std::nullopt, emptyString(), { } };
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auto observer = IntersectionObserver::create(document, WTFMove(callback), WTFMove(options));
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if (observer.hasException())
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return nullptr;
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m_observer = observer.returnValue().ptr();
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}
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return m_observer.get();
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}
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bool LazyLoadImageObserver::isObserved(Element& element) const
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{
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return m_observer && m_observer->isObserving(element);
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}
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}
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