dom/base/DOMIntersectionObserver.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
   5  * You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef DOMIntersectionObserver_h
   8 #define DOMIntersectionObserver_h
   9
  10 #include "mozilla/Attributes.h"
  11 #include "mozilla/dom/IntersectionObserverBinding.h"
  12 #include "mozilla/ServoStyleConsts.h"
  13 #include "mozilla/Variant.h"
  14 #include "nsDOMNavigationTiming.h"
  15 #include "nsTArray.h"
  16 #include "nsTHashSet.h"
  17
  18 namespace mozilla {
  19 namespace dom {
  20
  21 class DOMIntersectionObserver;
  22
  23 class DOMIntersectionObserverEntry final : public nsISupports,
  24                                            public nsWrapperCache {
  25   ~DOMIntersectionObserverEntry() = default;
  26
  27  public:
  28   DOMIntersectionObserverEntry(nsISupports* aOwner, DOMHighResTimeStamp aTime,
  29                                RefPtr<DOMRect> aRootBounds,
  30                                RefPtr<DOMRect> aBoundingClientRect,
  31                                RefPtr<DOMRect> aIntersectionRect,
  32                                bool aIsIntersecting, Element* aTarget,
  33                                double aIntersectionRatio)
  34       : mOwner(aOwner),
  35         mTime(aTime),
  36         mRootBounds(std::move(aRootBounds)),
  37         mBoundingClientRect(std::move(aBoundingClientRect)),
  38         mIntersectionRect(std::move(aIntersectionRect)),
  39         mIsIntersecting(aIsIntersecting),
  40         mTarget(aTarget),
  41         mIntersectionRatio(aIntersectionRatio) {}
  42   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
  43   NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(DOMIntersectionObserverEntry)
  44
  45   nsISupports* GetParentObject() const { return mOwner; }
  46
  47   JSObject* WrapObject(JSContext* aCx,
  48                        JS::Handle<JSObject*> aGivenProto) override {
  49     return IntersectionObserverEntry_Binding::Wrap(aCx, this, aGivenProto);
  50   }
  51
  52   DOMHighResTimeStamp Time() const { return mTime; }
  53
  54   DOMRect* GetRootBounds() { return mRootBounds; }
  55
  56   DOMRect* BoundingClientRect() { return mBoundingClientRect; }
  57
  58   DOMRect* IntersectionRect() { return mIntersectionRect; }
  59
  60   bool IsIntersecting() const { return mIsIntersecting; }
  61
  62   double IntersectionRatio() const { return mIntersectionRatio; }
  63
  64   Element* Target() { return mTarget; }
  65
  66  protected:
  67   nsCOMPtr<nsISupports> mOwner;
  68   DOMHighResTimeStamp mTime;
  69   RefPtr<DOMRect> mRootBounds;
  70   RefPtr<DOMRect> mBoundingClientRect;
  71   RefPtr<DOMRect> mIntersectionRect;
  72   bool mIsIntersecting;
  73   RefPtr<Element> mTarget;
  74   double mIntersectionRatio;
  75 };
  76
  77 #define NS_DOM_INTERSECTION_OBSERVER_IID             \
  78   {                                                  \
  79     0x8570a575, 0xe303, 0x4d18, {                    \
  80       0xb6, 0xb1, 0x4d, 0x2b, 0x49, 0xd8, 0xef, 0x94 \
  81     }                                                \
  82   }
  83
  84 class DOMIntersectionObserver final : public nsISupports,
  85                                       public nsWrapperCache {
  86   virtual ~DOMIntersectionObserver() { Disconnect(); }
  87
  88   using NativeCallback = void (*)(
  89       const Sequence<OwningNonNull<DOMIntersectionObserverEntry>>& aEntries);
  90   DOMIntersectionObserver(Document&, NativeCallback);
  91
  92  public:
  93   DOMIntersectionObserver(already_AddRefed<nsPIDOMWindowInner>&& aOwner,
  94                           dom::IntersectionCallback& aCb);
  95   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
  96   NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(DOMIntersectionObserver)
  97   NS_DECLARE_STATIC_IID_ACCESSOR(NS_DOM_INTERSECTION_OBSERVER_IID)
  98
  99   static already_AddRefed<DOMIntersectionObserver> Constructor(
 100       const GlobalObject&, dom::IntersectionCallback&, ErrorResult&);
 101   static already_AddRefed<DOMIntersectionObserver> Constructor(
 102       const GlobalObject&, dom::IntersectionCallback&,
 103       const IntersectionObserverInit&, ErrorResult&);
 104
 105   JSObject* WrapObject(JSContext* aCx,
 106                        JS::Handle<JSObject*> aGivenProto) override {
 107     return IntersectionObserver_Binding::Wrap(aCx, this, aGivenProto);
 108   }
 109
 110   nsISupports* GetParentObject() const;
 111
 112   nsINode* GetRoot() const { return mRoot; }
 113
 114   void GetRootMargin(nsACString&);
 115   bool SetRootMargin(const nsACString&);
 116
 117   void GetThresholds(nsTArray<double>& aRetVal);
 118   void Observe(Element& aTarget);
 119   void Unobserve(Element& aTarget);
 120
 121   void UnlinkTarget(Element& aTarget);
 122   void Disconnect();
 123
 124   void TakeRecords(nsTArray<RefPtr<DOMIntersectionObserverEntry>>& aRetVal);
 125
 126   void Update(Document* aDocument, DOMHighResTimeStamp time);
 127   MOZ_CAN_RUN_SCRIPT void Notify();
 128
 129   static already_AddRefed<DOMIntersectionObserver> CreateLazyLoadObserver(
 130       Document&);
 131   static already_AddRefed<DOMIntersectionObserver>
 132   CreateLazyLoadObserverViewport(Document&);
 133
 134  protected:
 135   void Connect();
 136   void QueueIntersectionObserverEntry(Element* aTarget,
 137                                       DOMHighResTimeStamp time,
 138                                       const Maybe<nsRect>& aRootRect,
 139                                       const nsRect& aTargetRect,
 140                                       const Maybe<nsRect>& aIntersectionRect,
 141                                       bool aIsIntersecting,
 142                                       double aIntersectionRatio);
 143
 144   nsCOMPtr<nsPIDOMWindowInner> mOwner;
 145   RefPtr<Document> mDocument;
 146   Variant<RefPtr<dom::IntersectionCallback>, NativeCallback> mCallback;
 147   RefPtr<nsINode> mRoot;
 148   StyleRect<LengthPercentage> mRootMargin;
 149   nsTArray<double> mThresholds;
 150
 151   // These hold raw pointers which are explicitly cleared by UnlinkTarget().
 152   //
 153   // We keep a set and an array because we need ordered access, but also
 154   // constant time lookup.
 155   nsTArray<Element*> mObservationTargets;
 156   nsTHashSet<Element*> mObservationTargetSet;
 157
 158   nsTArray<RefPtr<DOMIntersectionObserverEntry>> mQueuedEntries;
 159   bool mConnected;
 160 };
 161
 162 NS_DEFINE_STATIC_IID_ACCESSOR(DOMIntersectionObserver,
 163                               NS_DOM_INTERSECTION_OBSERVER_IID)
 164
 165 }  // namespace dom
 166 }  // namespace mozilla
 167
 168 #endif