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069fbaa157
Need to write a test for this. Also, as a matter of preventive measure, null out mOwner when it dies. That may matter in the case where the controller dies while the observer is getting notified. In that case, somebody still keeps a reference to the controller. Right now is fine because nothing will touch it again (the destructor doesn't), but that's not great, and it's better to just clear the pointer. Differential Revision: https://phabricator.services.mozilla.com/D29395 --HG-- extra : moz-landing-system : lando
131 lines
3.7 KiB
C++
131 lines
3.7 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this file,
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* You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef mozilla_dom_ResizeObserverController_h
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#define mozilla_dom_ResizeObserverController_h
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#include "mozilla/dom/ResizeObserver.h"
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#include "mozilla/TimeStamp.h"
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#include "nsRefreshDriver.h"
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#include "nsTObserverArray.h"
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namespace mozilla {
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class PresShell;
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namespace dom {
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class Document;
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class ResizeObserverController;
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/**
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* ResizeObserverNotificationHelper will trigger ResizeObserver notifications
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* by registering with the Refresh Driver.
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*/
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class ResizeObserverNotificationHelper final : public nsARefreshObserver {
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public:
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NS_INLINE_DECL_REFCOUNTING(ResizeObserverNotificationHelper, override)
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explicit ResizeObserverNotificationHelper(ResizeObserverController* aOwner)
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: mOwner(aOwner), mRegistered(false) {
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MOZ_ASSERT(mOwner, "Need a non-null owner");
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}
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MOZ_CAN_RUN_SCRIPT void WillRefresh(TimeStamp aTime) override;
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nsRefreshDriver* GetRefreshDriver() const;
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void Register();
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void Unregister();
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bool IsRegistered() const { return mRegistered; }
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void DetachFromOwner() { mOwner = nullptr; }
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private:
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virtual ~ResizeObserverNotificationHelper();
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ResizeObserverController* mOwner;
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bool mRegistered;
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};
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/**
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* ResizeObserverController contains the list of ResizeObservers and controls
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* the flow of notification.
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*/
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class ResizeObserverController final {
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public:
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explicit ResizeObserverController(Document* aDocument)
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: mDocument(aDocument),
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mResizeObserverNotificationHelper(
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new ResizeObserverNotificationHelper(this)) {
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MOZ_ASSERT(mDocument, "Need a non-null document");
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}
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// Methods for supporting cycle-collection
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void Traverse(nsCycleCollectionTraversalCallback& aCb);
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void Unlink();
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void ShellDetachedFromDocument();
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void AddResizeObserver(ResizeObserver* aObserver);
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/**
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* Schedule the notification via ResizeObserverNotificationHelper refresh
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* observer.
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*/
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void ScheduleNotification();
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/**
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* Notify all ResizeObservers by gathering and broadcasting all active
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* observations.
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*/
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MOZ_CAN_RUN_SCRIPT void Notify();
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PresShell* GetPresShell() const { return mDocument->GetPresShell(); }
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~ResizeObserverController();
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private:
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/**
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* Calls GatherActiveObservations(aDepth) for all ResizeObservers in this
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* controller. All observations in each ResizeObserver with element's depth
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* more than aDepth will be gathered.
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*/
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void GatherAllActiveObservations(uint32_t aDepth);
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/**
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* Calls BroadcastActiveObservations() for all ResizeObservers in this
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* controller. It also returns the shallowest depth of observed target
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* elements with active observations from all ResizeObservers or
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* numeric_limits<uint32_t>::max() if there aren't any active observations
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* at all.
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*/
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MOZ_CAN_RUN_SCRIPT uint32_t BroadcastAllActiveObservations();
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/**
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* Returns whether there is any ResizeObserver that has active observations.
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*/
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bool HasAnyActiveObservations() const;
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/**
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* Returns whether there is any ResizeObserver that has skipped observations.
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*/
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bool HasAnySkippedObservations() const;
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// Raw pointer is OK because mDocument strongly owns us & hence must outlive
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// us.
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Document* const mDocument;
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RefPtr<ResizeObserverNotificationHelper> mResizeObserverNotificationHelper;
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nsTObserverArray<RefPtr<ResizeObserver>> mResizeObservers;
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};
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} // namespace dom
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} // namespace mozilla
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#endif // mozilla_dom_ResizeObserverController_h
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