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/*
* Copyright (C) 2016 Apple Inc. 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.
*/
#pragma once
#include "Document.h"
#include "GCReachableRef.h"
#include "IntersectionObserverCallback.h"
#include "LengthBox.h"
#include "ReducedResolutionSeconds.h"
#include <variant>
#include <wtf/RefCountedAndCanMakeWeakPtr.h>
#include <wtf/WeakPtr.h>
#include <wtf/text/WTFString.h>
namespace JSC {
class AbstractSlotVisitor;
}
namespace WebCore {
class ContainerNode;
class Document;
class Element;
class IntersectionObserverEntry;
struct IntersectionObserverRegistration {
WeakPtr<IntersectionObserver> observer;
std::optional<size_t> previousThresholdIndex;
};
struct IntersectionObserverData {
WTF_MAKE_STRUCT_FAST_ALLOCATED;
// IntersectionObservers for which the node that owns this IntersectionObserverData is the root.
// An IntersectionObserver is only owned by a JavaScript wrapper. ActiveDOMObject::virtualHasPendingActivity
// is overridden to keep this wrapper alive while the observer has ongoing observations.
Vector<WeakPtr<IntersectionObserver>> observers;
// IntersectionObserverRegistrations for which the node that owns this IntersectionObserverData is the target.
Vector<IntersectionObserverRegistration> registrations;
};
class IntersectionObserver : public RefCountedAndCanMakeWeakPtr<IntersectionObserver> {
WTF_MAKE_TZONE_OR_ISO_ALLOCATED(IntersectionObserver);
public:
struct Init {
std::optional<std::variant<RefPtr<Element>, RefPtr<Document>>> root;
String rootMargin;
std::variant<double, Vector<double>> threshold;
};
static ExceptionOr<Ref<IntersectionObserver>> create(Document&, Ref<IntersectionObserverCallback>&&, Init&&);
~IntersectionObserver();
Document* trackingDocument() const { return m_root ? &m_root->document() : m_implicitRootDocument.get(); }
ContainerNode* root() const { return m_root.get(); }
String rootMargin() const;
const LengthBox& rootMarginBox() const { return m_rootMargin; }
const Vector<double>& thresholds() const { return m_thresholds; }
const Vector<WeakPtr<Element, WeakPtrImplWithEventTargetData>>& observationTargets() const { return m_observationTargets; }
bool hasObservationTargets() const { return m_observationTargets.size(); }
bool isObserving(const Element&) const;
void observe(Element&);
void unobserve(Element&);
void disconnect();
struct TakenRecords {
Vector<Ref<IntersectionObserverEntry>> records;
Vector<GCReachableRef<Element>> pendingTargets;
};
TakenRecords takeRecords();
void targetDestroyed(Element&);
void rootDestroyed();
enum class NeedNotify : bool { No, Yes };
NeedNotify updateObservations(Document&);
std::optional<ReducedResolutionSeconds> nowTimestamp() const;
void appendQueuedEntry(Ref<IntersectionObserverEntry>&&);
void notify();
IntersectionObserverCallback* callbackConcurrently() { return m_callback.get(); }
bool isReachableFromOpaqueRoots(JSC::AbstractSlotVisitor&) const;
private:
IntersectionObserver(Document&, Ref<IntersectionObserverCallback>&&, ContainerNode* root, LengthBox&& parsedRootMargin, Vector<double>&& thresholds);
bool removeTargetRegistration(Element&);
void removeAllTargets();
struct IntersectionObservationState {
FloatRect rootBounds;
std::optional<FloatRect> absoluteIntersectionRect; // Only computed if intersecting.
std::optional<FloatRect> absoluteTargetRect; // Only computed if first observation, or intersecting.
std::optional<FloatRect> absoluteRootBounds; // Only computed if observationChanged.
float intersectionRatio { 0 };
size_t thresholdIndex { 0 };
bool canComputeIntersection { false };
bool isIntersecting { false };
bool observationChanged { false };
};
IntersectionObservationState computeIntersectionState(const IntersectionObserverRegistration&, LocalFrameView&, Element& target, bool applyRootMargin) const;
WeakPtr<Document, WeakPtrImplWithEventTargetData> m_implicitRootDocument;
WeakPtr<ContainerNode, WeakPtrImplWithEventTargetData> m_root;
LengthBox m_rootMargin;
Vector<double> m_thresholds;
RefPtr<IntersectionObserverCallback> m_callback;
Vector<WeakPtr<Element, WeakPtrImplWithEventTargetData>> m_observationTargets;
Vector<GCReachableRef<Element>> m_pendingTargets;
Vector<Ref<IntersectionObserverEntry>> m_queuedEntries;
Vector<GCReachableRef<Element>> m_targetsWaitingForFirstObservation;
};
} // namespace WebCore
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