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       1             : /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
       2             : /* vim: set shiftwidth=2 tabstop=8 autoindent cindent expandtab: */
       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
       5             :  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
       6             : 
       7             : /* implements DOM interface for querying and observing media queries */
       8             : 
       9             : #ifndef mozilla_dom_MediaQueryList_h
      10             : #define mozilla_dom_MediaQueryList_h
      11             : 
      12             : #include "nsISupports.h"
      13             : #include "nsCycleCollectionParticipant.h"
      14             : #include "nsCOMPtr.h"
      15             : #include "nsTArray.h"
      16             : #include "mozilla/LinkedList.h"
      17             : #include "mozilla/Attributes.h"
      18             : #include "nsWrapperCache.h"
      19             : #include "mozilla/DOMEventTargetHelper.h"
      20             : #include "mozilla/dom/MediaQueryListBinding.h"
      21             : 
      22             : class nsIDocument;
      23             : 
      24             : namespace mozilla {
      25             : namespace dom {
      26             : 
      27             : class MediaList;
      28             : 
      29             : class MediaQueryList final : public DOMEventTargetHelper,
      30             :                              public mozilla::LinkedListElement<MediaQueryList>
      31             : {
      32             : public:
      33             :   // The caller who constructs is responsible for calling Evaluate
      34             :   // before calling any other methods.
      35             :   MediaQueryList(nsIDocument *aDocument,
      36             :                  const nsAString &aMediaQueryList);
      37             : private:
      38             :   ~MediaQueryList();
      39             : 
      40             : public:
      41             :   NS_DECL_ISUPPORTS_INHERITED
      42          33 :   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(MediaQueryList, DOMEventTargetHelper)
      43             : 
      44             :   nsISupports* GetParentObject() const;
      45             : 
      46             :   void MaybeNotify();
      47             : 
      48             :   JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;
      49             : 
      50             :   // WebIDL methods
      51             :   void GetMedia(nsAString& aMedia);
      52             :   bool Matches();
      53             :   void AddListener(EventListener* aListener, ErrorResult& aRv);
      54             :   void RemoveListener(EventListener* aListener, ErrorResult& aRv);
      55             : 
      56             :   using nsIDOMEventTarget::AddEventListener;
      57             : 
      58             :   virtual void AddEventListener(const nsAString& aType,
      59             :                                 EventListener* aCallback,
      60             :                                 const AddEventListenerOptionsOrBoolean& aOptions,
      61             :                                 const Nullable<bool>& aWantsUntrusted,
      62             :                                 ErrorResult& aRv) override;
      63             : 
      64           0 :   IMPL_EVENT_HANDLER(change)
      65             : 
      66             :   bool HasListeners();
      67             : 
      68             :   void Disconnect();
      69             : 
      70             : private:
      71             :   void RecomputeMatches();
      72             : 
      73             :   // We only need a pointer to the document to support lazy
      74             :   // reevaluation following dynamic changes.  However, this lazy
      75             :   // reevaluation is perhaps somewhat important, since some usage
      76             :   // patterns may involve the creation of large numbers of
      77             :   // MediaQueryList objects which almost immediately become garbage
      78             :   // (after a single call to the .matches getter).
      79             :   //
      80             :   // This pointer does make us a little more dependent on cycle
      81             :   // collection.
      82             :   //
      83             :   // We have a non-null mDocument for our entire lifetime except
      84             :   // after cycle collection unlinking.  Having a non-null mDocument
      85             :   // is equivalent to being in that document's mDOMMediaQueryLists
      86             :   // linked list.
      87             :   nsCOMPtr<nsIDocument> mDocument;
      88             : 
      89             :   RefPtr<MediaList> mMediaList;
      90             :   bool mMatches;
      91             :   bool mMatchesValid;
      92             : };
      93             : 
      94             : } // namespace dom
      95             : } // namespace mozilla
      96             : 
      97             : #endif /* !defined(mozilla_dom_MediaQueryList_h) */