Quelle DOMIntersectionObserver.cpp Sprache: C

/* -*- 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 http://mozilla.org/MPL/2.0/. */

#include "DOMIntersectionObserver.h"
#include "nsCSSPropertyID.h"
#include "nsIFrame.h"
#include "nsContainerFrame.h"
#include "nsContentUtils.h"
#include "nsLayoutUtils.h"
#include "nsRefreshDriver.h"
#include "mozilla/PresShell.h"
#include "mozilla/ScrollContainerFrame.h"
#include "mozilla/StaticPrefs_dom.h"
#include "mozilla/StaticPrefs_layout.h"
#include "mozilla/ServoBindings.h"
#include "mozilla/dom/BrowserChild.h"
#include "mozilla/dom/BrowsingContext.h"
#include "mozilla/dom/DocumentInlines.h"
#include "mozilla/dom/HTMLImageElement.h"
#include "mozilla/dom/HTMLIFrameElement.h"
#include "Units.h"

namespace mozilla::dom {

NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(DOMIntersectionObserverEntry)
  NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
  NS_INTERFACE_MAP_ENTRY(nsISupports)
NS_INTERFACE_MAP_END

NS_IMPL_CYCLE_COLLECTING_ADDREF(DOMIntersectionObserverEntry)
NS_IMPL_CYCLE_COLLECTING_RELEASE(DOMIntersectionObserverEntry)

NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(DOMIntersectionObserverEntry, mOwner,
                                      mRootBounds, mBoundingClientRect,
                                      mIntersectionRect, mTarget)

NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(DOMIntersectionObserver)
  NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
  NS_INTERFACE_MAP_ENTRY(nsISupports)
  NS_INTERFACE_MAP_ENTRY(DOMIntersectionObserver)
NS_INTERFACE_MAP_END

NS_IMPL_CYCLE_COLLECTING_ADDREF(DOMIntersectionObserver)
NS_IMPL_CYCLE_COLLECTING_RELEASE(DOMIntersectionObserver)

NS_IMPL_CYCLE_COLLECTION_CLASS(DOMIntersectionObserver)

NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(DOMIntersectionObserver)
  NS_IMPL_CYCLE_COLLECTION_TRACE_PRESERVED_WRAPPER
NS_IMPL_CYCLE_COLLECTION_TRACE_END

NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(DOMIntersectionObserver)
  NS_IMPL_CYCLE_COLLECTION_UNLINK_PRESERVED_WRAPPER
  tmp->Disconnect();
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mOwner)
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mDocument)
  if (tmp->mCallback.is<RefPtr<dom::IntersectionCallback>>()) {
    ImplCycleCollectionUnlink(
        tmp->mCallback.as<RefPtr<dom::IntersectionCallback>>());
  }
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mRoot)
  NS_IMPL_CYCLE_COLLECTION_UNLINK(mQueuedEntries)
NS_IMPL_CYCLE_COLLECTION_UNLINK_END

NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(DOMIntersectionObserver)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mOwner)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mDocument)
  if (tmp->mCallback.is<RefPtr<dom::IntersectionCallback>>()) {
    ImplCycleCollectionTraverse(
        cb, tmp->mCallback.as<RefPtr<dom::IntersectionCallback>>(), "mCallback",
        0);
  }
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mRoot)
  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mQueuedEntries)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END

DOMIntersectionObserver::DOMIntersectionObserver(
    already_AddRefed<nsPIDOMWindowInner>&& aOwner,
    dom::IntersectionCallback& aCb)
    : mOwner(aOwner),
      mDocument(mOwner->GetExtantDoc()),
      mCallback(RefPtr<dom::IntersectionCallback>(&aCb)) {}

already_AddRefed<DOMIntersectionObserver> DOMIntersectionObserver::Constructor(
    const GlobalObject& aGlobal, dom::IntersectionCallback& aCb,
    ErrorResult& aRv) {
  return Constructor(aGlobal, aCb, IntersectionObserverInit(), aRv);
}

already_AddRefed<DOMIntersectionObserver> DOMIntersectionObserver::Constructor(
    const GlobalObject& aGlobal, dom::IntersectionCallback& aCb,
    const IntersectionObserverInit& aOptions, ErrorResult& aRv) {
  nsCOMPtr<nsPIDOMWindowInner> window =
      do_QueryInterface(aGlobal.GetAsSupports());
  if (!window) {
    aRv.Throw(NS_ERROR_FAILURE);
    return nullptr;
  }
  RefPtr<DOMIntersectionObserver> observer =
      new DOMIntersectionObserver(window.forget(), aCb);

  if (!aOptions.mRoot.IsNull()) {
    if (aOptions.mRoot.Value().IsElement()) {
      observer->mRoot = aOptions.mRoot.Value().GetAsElement();
    } else {
      MOZ_ASSERT(aOptions.mRoot.Value().IsDocument());
      observer->mRoot = aOptions.mRoot.Value().GetAsDocument();
    }
  }

  if (!observer->SetRootMargin(aOptions.mRootMargin)) {
    aRv.ThrowSyntaxError("rootMargin must be specified in pixels or percent.");
    return nullptr;
  }

  if (aOptions.mThreshold.IsDoubleSequence()) {
    const Sequence<double>& thresholds =
        aOptions.mThreshold.GetAsDoubleSequence();
    observer->mThresholds.SetCapacity(thresholds.Length());
    for (const auto& thresh : thresholds) {
      if (thresh < 0.0 || thresh > 1.0) {
        aRv.ThrowRangeError<dom::MSG_THRESHOLD_RANGE_ERROR>();
        return nullptr;
      }
      observer->mThresholds.AppendElement(thresh);
    }
    observer->mThresholds.Sort();
    if (observer->mThresholds.IsEmpty()) {
      observer->mThresholds.AppendElement(0.0);
    }
  } else {
    double thresh = aOptions.mThreshold.GetAsDouble();
    if (thresh < 0.0 || thresh > 1.0) {
      aRv.ThrowRangeError<dom::MSG_THRESHOLD_RANGE_ERROR>();
      return nullptr;
    }
    observer->mThresholds.AppendElement(thresh);
  }

  return observer.forget();
}

static void LazyLoadCallback(
    const Sequence<OwningNonNull<DOMIntersectionObserverEntry>>& aEntries) {
  for (const auto& entry : aEntries) {
    Element* target = entry->Target();
    if (entry->IsIntersecting()) {
      if (auto* image = HTMLImageElement::FromNode(target)) {
        image->StopLazyLoading();
      } else if (auto* iframe = HTMLIFrameElement::FromNode(target)) {
        iframe->StopLazyLoading();
      } else {
        MOZ_ASSERT_UNREACHABLE(
            "Only and