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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
* You can obtain one at */
#ifndef DOMIntersectionObserver_h
#define DOMIntersectionObserver_h
#include "mozilla/Attributes.h"
#include "mozilla/dom/IntersectionObserverBinding.h"
#include "mozilla/ServoStyleConsts.h"
#include "mozilla/Variant.h"
#include "nsDOMNavigationTiming.h"
#include "nsTArray.h"
#include "nsTHashSet.h"
namespace mozilla::dom {
class DOMIntersectionObserver;
class DOMIntersectionObserverEntry final : public nsISupports,
public nsWrapperCache {
~DOMIntersectionObserverEntry() = default;
DOMIntersectionObserverEntry(nsISupports* aOwner, DOMHighResTimeStamp aTime,
RefPtr<DOMRect> aRootBounds,
RefPtr<DOMRect> aBoundingClientRect,
RefPtr<DOMRect> aIntersectionRect,
bool aIsIntersecting, Element* aTarget,
double aIntersectionRatio)
: mOwner(aOwner),
mIntersectionRatio(aIntersectionRatio) {}
nsISupports* GetParentObject() const { return mOwner; }
JSObject* WrapObject(JSContext* aCx,
JS::Handle<JSObject*> aGivenProto) override {
return IntersectionObserverEntry_Binding::Wrap(aCx, this, aGivenProto);
DOMHighResTimeStamp Time() const { return mTime; }
DOMRect* GetRootBounds() { return mRootBounds; }
DOMRect* BoundingClientRect() { return mBoundingClientRect; }
DOMRect* IntersectionRect() { return mIntersectionRect; }
bool IsIntersecting() const { return mIsIntersecting; }
double IntersectionRatio() const { return mIntersectionRatio; }
Element* Target() { return mTarget; }
nsCOMPtr<nsISupports> mOwner;
DOMHighResTimeStamp mTime;
RefPtr<DOMRect> mRootBounds;
RefPtr<DOMRect> mBoundingClientRect;
RefPtr<DOMRect> mIntersectionRect;
bool mIsIntersecting;
RefPtr<Element> mTarget;
double mIntersectionRatio;
{ \
0x8570a575, 0xe303, 0x4d18, { \
0xb6, 0xb1, 0x4d, 0x2b, 0x49, 0xd8, 0xef, 0x94 \
} \
// An input suitable to compute intersections with multiple targets.
struct IntersectionInput {
// Whether the root is implicit (null, originally).
const bool mIsImplicitRoot = false;
// The computed root node. For the implicit root, this will be the in-process
// root document we can compute coordinates against (along with the remote
// document visible rect if appropriate).
const nsINode* mRootNode = nullptr;
nsIFrame* mRootFrame = nullptr;
// The rect of mRootFrame in client coordinates.
nsRect mRootRect;
// The root margin computed against the root rect.
nsMargin mRootMargin;
// If this is in an OOP iframe, the visible rect of the OOP frame.
Maybe<nsRect> mRemoteDocumentVisibleRect;
struct IntersectionOutput {
const bool mIsSimilarOrigin;
const nsRect mRootBounds;
const nsRect mTargetRect;
const Maybe<nsRect> mIntersectionRect;
bool Intersects() const { return mIntersectionRect.isSome(); }
class DOMIntersectionObserver final : public nsISupports,
public nsWrapperCache {
virtual ~DOMIntersectionObserver() { Disconnect(); }
using NativeCallback = void (*)(
const Sequence<OwningNonNull<DOMIntersectionObserverEntry>>& aEntries);
DOMIntersectionObserver(Document&, NativeCallback);
DOMIntersectionObserver(already_AddRefed<nsPIDOMWindowInner>&& aOwner,
dom::IntersectionCallback& aCb);
static already_AddRefed<DOMIntersectionObserver> Constructor(
const GlobalObject&, dom::IntersectionCallback&, ErrorResult&);
static already_AddRefed<DOMIntersectionObserver> Constructor(
const GlobalObject&, dom::IntersectionCallback&,
const IntersectionObserverInit&, ErrorResult&);
JSObject* WrapObject(JSContext* aCx,
JS::Handle<JSObject*> aGivenProto) override {
return IntersectionObserver_Binding::Wrap(aCx, this, aGivenProto);
nsISupports* GetParentObject() const;
nsINode* GetRoot() const { return mRoot; }
void GetRootMargin(nsACString&);
bool SetRootMargin(const nsACString&);
void GetThresholds(nsTArray<double>& aRetVal);
void Observe(Element& aTarget);
void Unobserve(Element& aTarget);
void UnlinkTarget(Element& aTarget);
void Disconnect();
void TakeRecords(nsTArray<RefPtr<DOMIntersectionObserverEntry>>& aRetVal);
static IntersectionInput ComputeInput(
const Document& aDocument, const nsINode* aRoot,
const StyleRect<LengthPercentage>* aRootMargin);
enum class IsForProximityToViewport : bool { No, Yes };
static IntersectionOutput Intersect(
const IntersectionInput&, const Element&,
IsForProximityToViewport = IsForProximityToViewport::No);
// Intersects with a given rect, already relative to the root frame.
static IntersectionOutput Intersect(const IntersectionInput&, const nsRect&);
void Update(Document& aDocument, DOMHighResTimeStamp time);
MOZ_CAN_RUN_SCRIPT void Notify();
static already_AddRefed<DOMIntersectionObserver> CreateLazyLoadObserver(
static Maybe<nsRect> EdgeInclusiveIntersection(const nsRect& aRect,
const nsRect& aOtherRect);
void Connect();
void QueueIntersectionObserverEntry(Element* aTarget,
DOMHighResTimeStamp time,
const Maybe<nsRect>& aRootRect,
const nsRect& aTargetRect,
const Maybe<nsRect>& aIntersectionRect,
bool aIsIntersecting,
double aIntersectionRatio);
nsCOMPtr<nsPIDOMWindowInner> mOwner;
RefPtr<Document> mDocument;
Variant<RefPtr<dom::IntersectionCallback>, NativeCallback> mCallback;
RefPtr<nsINode> mRoot;
StyleRect<LengthPercentage> mRootMargin;
AutoTArray<double, 1> mThresholds;
// These hold raw pointers which are explicitly cleared by UnlinkTarget().
// We keep a set and an array because we need ordered access, but also
// constant time lookup.
nsTArray<Element*> mObservationTargets;
nsTHashSet<Element*> mObservationTargetSet;
nsTArray<RefPtr<DOMIntersectionObserverEntry>> mQueuedEntries;
bool mConnected = false;
} // namespace mozilla::dom