layout/base/nsRefreshDriver.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
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 /*
   8  * Code to notify things that animate before a refresh, at an appropriate
   9  * refresh rate.  (Perhaps temporary, until replaced by compositor.)
  10  */
  11
  12 #ifndef nsRefreshDriver_h_
  13 #define nsRefreshDriver_h_
  14
  15 #include "mozilla/FlushType.h"
  16 #include "mozilla/TimeStamp.h"
  17 #include "mozilla/UniquePtr.h"
  18 #include "mozilla/Vector.h"
  19 #include "mozilla/WeakPtr.h"
  20 #include "nsTObserverArray.h"
  21 #include "nsTArray.h"
  22 #include "nsTHashSet.h"
  23 #include "nsClassHashtable.h"
  24 #include "nsHashKeys.h"
  25 #include "nsRefreshObservers.h"
  26 #include "nsThreadUtils.h"
  27 #include "mozilla/Attributes.h"
  28 #include "mozilla/Maybe.h"
  29 #include "mozilla/dom/VisualViewport.h"
  30 #include "mozilla/layers/TransactionIdAllocator.h"
  31 #include "LayersTypes.h"
  32
  33 #include "GeckoProfiler.h"  // for ProfileChunkedBuffer
  34
  35 class nsPresContext;
  36
  37 class imgIRequest;
  38 class nsIRunnable;
  39
  40 namespace mozilla {
  41 class AnimationEventDispatcher;
  42 class PendingFullscreenEvent;
  43 class PresShell;
  44 class RefreshDriverTimer;
  45 class Runnable;
  46 class Task;
  47 }  // namespace mozilla
  48
  49 class nsRefreshDriver final : public mozilla::layers::TransactionIdAllocator,
  50                               public nsARefreshObserver {
  51   using Document = mozilla::dom::Document;
  52   using TransactionId = mozilla::layers::TransactionId;
  53   using VVPResizeEvent =
  54       mozilla::dom::VisualViewport::VisualViewportResizeEvent;
  55   using VVPScrollEvent =
  56       mozilla::dom::VisualViewport::VisualViewportScrollEvent;
  57   using LogPresShellObserver = mozilla::LogPresShellObserver;
  58
  59  public:
  60   explicit nsRefreshDriver(nsPresContext* aPresContext);
  61   ~nsRefreshDriver();
  62
  63   /**
  64    * Methods for testing, exposed via nsIDOMWindowUtils.  See
  65    * nsIDOMWindowUtils.advanceTimeAndRefresh for description.
  66    */
  67   void AdvanceTimeAndRefresh(int64_t aMilliseconds);
  68   void RestoreNormalRefresh();
  69   void DoTick();
  70   bool IsTestControllingRefreshesEnabled() const {
  71     return mTestControllingRefreshes;
  72   }
  73
  74   /**
  75    * Return the time of the most recent refresh.  This is intended to be
  76    * used by callers who want to start an animation now and want to know
  77    * what time to consider the start of the animation.  (This helps
  78    * ensure that multiple animations started during the same event off
  79    * the main event loop have the same start time.)
  80    */
  81   mozilla::TimeStamp MostRecentRefresh(bool aEnsureTimerStarted = true) const;
  82
  83   /**
  84    * Add / remove refresh observers.
  85    * RemoveRefreshObserver returns true if aObserver was found.
  86    *
  87    * The flush type affects:
  88    *   + the order in which the observers are notified (lowest flush
  89    *     type to highest, in order registered)
  90    *   + (in the future) which observers are suppressed when the display
  91    *     doesn't require current position data or isn't currently
  92    *     painting, and, correspondingly, which get notified when there
  93    *     is a flush during such suppression
  94    * and it must be FlushType::Style, FlushType::Layout, or FlushType::Display.
  95    *
  96    * The refresh driver does NOT own a reference to these observers;
  97    * they must remove themselves before they are destroyed.
  98    *
  99    * The observer will be called even if there is no other activity.
 100    */
 101   void AddRefreshObserver(nsARefreshObserver* aObserver,
 102                           mozilla::FlushType aFlushType,
 103                           const char* aObserverDescription);
 104   bool RemoveRefreshObserver(nsARefreshObserver* aObserver,
 105                              mozilla::FlushType aFlushType);
 106   /**
 107    * Add / remove an observer wants to know the time when the refresh driver
 108    * updated the most recent refresh time due to its active timer changes.
 109    */
 110   void AddTimerAdjustmentObserver(nsATimerAdjustmentObserver* aObserver);
 111   void RemoveTimerAdjustmentObserver(nsATimerAdjustmentObserver* aObserver);
 112
 113   void PostVisualViewportResizeEvent(VVPResizeEvent* aResizeEvent);
 114   void DispatchVisualViewportResizeEvents();
 115
 116   void PostScrollEvent(mozilla::Runnable* aScrollEvent, bool aDelayed = false);
 117   void DispatchScrollEvents();
 118
 119   void PostVisualViewportScrollEvent(VVPScrollEvent* aScrollEvent);
 120   void DispatchVisualViewportScrollEvents();
 121
 122   /**
 123    * Add an observer that will be called after each refresh. The caller
 124    * must remove the observer before it is deleted. This does not trigger
 125    * refresh driver ticks.
 126    */
 127   void AddPostRefreshObserver(nsAPostRefreshObserver* aObserver);
 128   void AddPostRefreshObserver(mozilla::ManagedPostRefreshObserver*) = delete;
 129   void RemovePostRefreshObserver(nsAPostRefreshObserver* aObserver);
 130   void RemovePostRefreshObserver(mozilla::ManagedPostRefreshObserver*) = delete;
 131
 132   /**
 133    * Add/Remove imgIRequest versions of observers.
 134    *
 135    * These are used for hooking into the refresh driver for
 136    * controlling animated images.
 137    *
 138    * @note The refresh driver owns a reference to these listeners.
 139    *
 140    * @note Technically, imgIRequest objects are not nsARefreshObservers, but
 141    * for controlling animated image repaint events, we subscribe the
 142    * imgIRequests to the nsRefreshDriver for notification of paint events.
 143    */
 144   void AddImageRequest(imgIRequest* aRequest);
 145   void RemoveImageRequest(imgIRequest* aRequest);
 146
 147   /**
 148    * Marks that we're currently in the middle of processing user input.
 149    * Called by EventDispatcher when it's handling an input event.
 150    */
 151   void EnterUserInputProcessing() { mUserInputProcessingCount++; }
 152   void ExitUserInputProcessing() {
 153     MOZ_ASSERT(mUserInputProcessingCount > 0);
 154     mUserInputProcessingCount--;
 155   }
 156
 157   /**
 158    * Add / remove presshells which have pending resize event.
 159    */
 160   void AddResizeEventFlushObserver(mozilla::PresShell* aPresShell,
 161                                    bool aDelayed = false) {
 162     MOZ_DIAGNOSTIC_ASSERT(
 163         !mResizeEventFlushObservers.Contains(aPresShell) &&
 164             !mDelayedResizeEventFlushObservers.Contains(aPresShell),
 165         "Double-adding resize event flush observer");
 166     if (aDelayed) {
 167       mDelayedResizeEventFlushObservers.AppendElement(aPresShell);
 168     } else {
 169       mResizeEventFlushObservers.AppendElement(aPresShell);
 170       EnsureTimerStarted();
 171     }
 172   }
 173
 174   void RemoveResizeEventFlushObserver(mozilla::PresShell* aPresShell) {
 175     mResizeEventFlushObservers.RemoveElement(aPresShell);
 176     mDelayedResizeEventFlushObservers.RemoveElement(aPresShell);
 177   }
 178
 179   /**
 180    * Add / remove presshells that we should flush style and layout on
 181    */
 182   void AddStyleFlushObserver(mozilla::PresShell* aPresShell) {
 183     MOZ_DIAGNOSTIC_ASSERT(!mStyleFlushObservers.Contains(aPresShell),
 184                           "Double-adding style flush observer");
 185     LogPresShellObserver::LogDispatch(aPresShell, this);
 186     mStyleFlushObservers.AppendElement(aPresShell);
 187     EnsureTimerStarted();
 188   }
 189
 190   void RemoveStyleFlushObserver(mozilla::PresShell* aPresShell) {
 191     mStyleFlushObservers.RemoveElement(aPresShell);
 192   }
 193   void AddLayoutFlushObserver(mozilla::PresShell* aPresShell) {
 194     MOZ_DIAGNOSTIC_ASSERT(!IsLayoutFlushObserver(aPresShell),
 195                           "Double-adding layout flush observer");
 196     LogPresShellObserver::LogDispatch(aPresShell, this);
 197     mLayoutFlushObservers.AppendElement(aPresShell);
 198     EnsureTimerStarted();
 199   }
 200   void RemoveLayoutFlushObserver(mozilla::PresShell* aPresShell) {
 201     mLayoutFlushObservers.RemoveElement(aPresShell);
 202   }
 203
 204   bool IsLayoutFlushObserver(mozilla::PresShell* aPresShell) {
 205     return mLayoutFlushObservers.Contains(aPresShell);
 206   }
 207
 208   /**
 209    * "Early Runner" runnables will be called as the first step when refresh
 210    * driver tick is triggered. Runners shouldn't keep other objects alive,
 211    * since it isn't guaranteed they will ever get called.
 212    */
 213   void AddEarlyRunner(nsIRunnable* aRunnable) {
 214     mEarlyRunners.AppendElement(aRunnable);
 215     EnsureTimerStarted();
 216   }
 217
 218   /**
 219    * Remember whether our presshell's view manager needs a flush
 220    */
 221   void ScheduleViewManagerFlush();
 222   void RevokeViewManagerFlush() { mViewManagerFlushIsPending = false; }
 223   bool ViewManagerFlushIsPending() { return mViewManagerFlushIsPending; }
 224   bool HasScheduleFlush() { return mHasScheduleFlush; }
 225   void ClearHasScheduleFlush() { mHasScheduleFlush = false; }
 226
 227   /**
 228    * Add a document for which we have FrameRequestCallbacks
 229    */
 230   void ScheduleFrameRequestCallbacks(Document* aDocument);
 231
 232   /**
 233    * Remove a document for which we have FrameRequestCallbacks
 234    */
 235   void RevokeFrameRequestCallbacks(Document* aDocument);
 236
 237   /**
 238    * Queue a new fullscreen event to be dispatched in next tick before
 239    * the style flush
 240    */
 241   void ScheduleFullscreenEvent(
 242       mozilla::UniquePtr<mozilla::PendingFullscreenEvent> aEvent);
 243
 244   /**
 245    * Cancel all pending fullscreen events scheduled by ScheduleFullscreenEvent
 246    * which targets any node in aDocument.
 247    */
 248   void CancelPendingFullscreenEvents(Document* aDocument);
 249
 250   /**
 251    * Queue new animation events to dispatch in next tick.
 252    */
 253   void ScheduleAnimationEventDispatch(
 254       mozilla::AnimationEventDispatcher* aDispatcher) {
 255     NS_ASSERTION(!mAnimationEventFlushObservers.Contains(aDispatcher),
 256                  "Double-adding animation event flush observer");
 257     mAnimationEventFlushObservers.AppendElement(aDispatcher);
 258     EnsureTimerStarted();
 259   }
 260
 261   /**
 262    * Cancel all pending animation events associated with |aDispatcher|.
 263    */
 264   void CancelPendingAnimationEvents(
 265       mozilla::AnimationEventDispatcher* aDispatcher);
 266
 267   /**
 268    * Schedule a frame visibility update "soon", subject to the heuristics and
 269    * throttling we apply to visibility updates.
 270    */
 271   void ScheduleFrameVisibilityUpdate() { mNeedToRecomputeVisibility = true; }
 272
 273   /**
 274    * Tell the refresh driver that it is done driving refreshes and
 275    * should stop its timer and forget about its pres context.  This may
 276    * be called from within a refresh.
 277    */
 278   void Disconnect();
 279
 280   bool IsFrozen() const { return mFreezeCount > 0; }
 281
 282   bool IsThrottled() const { return mThrottled; }
 283
 284   /**
 285    * Freeze the refresh driver.  It should stop delivering future
 286    * refreshes until thawed. Note that the number of calls to Freeze() must
 287    * match the number of calls to Thaw() in order for the refresh driver to
 288    * be un-frozen.
 289    */
 290   void Freeze();
 291
 292   /**
 293    * Thaw the refresh driver.  If the number of calls to Freeze() matches the
 294    * number of calls to this function, the refresh driver should start
 295    * delivering refreshes again.
 296    */
 297   void Thaw();
 298
 299   /**
 300    * Throttle or unthrottle the refresh driver.  This is done if the
 301    * corresponding presshell is hidden or shown.
 302    */
 303   void SetActivity(bool aIsActive);
 304
 305   /**
 306    * Return the prescontext we were initialized with
 307    */
 308   nsPresContext* GetPresContext() const;
 309
 310   void CreateVsyncRefreshTimer();
 311
 312 #ifdef DEBUG
 313   /**
 314    * Check whether the given observer is an observer for the given flush type
 315    */
 316   bool IsRefreshObserver(nsARefreshObserver* aObserver,
 317                          mozilla::FlushType aFlushType);
 318 #endif
 319
 320   /**
 321    * Default interval the refresh driver uses, in ms.
 322    */
 323   static int32_t DefaultInterval();
 324
 325   /**
 326    * Returns true if a recent vsync interval has been less than a half of
 327    * DefaultInterval.
 328    */
 329   static bool IsInHighRateMode();
 330
 331   bool IsInRefresh() { return mInRefresh; }
 332
 333   void SetIsResizeSuppressed() { mResizeSuppressed = true; }
 334   bool IsResizeSuppressed() const { return mResizeSuppressed; }
 335
 336   // mozilla::layers::TransactionIdAllocator
 337   TransactionId GetTransactionId(bool aThrottle) override;
 338   TransactionId LastTransactionId() const override;
 339   void NotifyTransactionCompleted(TransactionId aTransactionId) override;
 340   void RevokeTransactionId(TransactionId aTransactionId) override;
 341   void ClearPendingTransactions() override;
 342   void ResetInitialTransactionId(TransactionId aTransactionId) override;
 343   mozilla::TimeStamp GetTransactionStart() override;
 344   mozilla::VsyncId GetVsyncId() override;
 345   mozilla::TimeStamp GetVsyncStart() override;
 346
 347   bool IsWaitingForPaint(mozilla::TimeStamp aTime);
 348
 349   void ScheduleAutoFocusFlush(Document* aDocument);
 350
 351   // nsARefreshObserver
 352   NS_IMETHOD_(MozExternalRefCountType) AddRef(void) override {
 353     return TransactionIdAllocator::AddRef();
 354   }
 355   NS_IMETHOD_(MozExternalRefCountType) Release(void) override {
 356     return TransactionIdAllocator::Release();
 357   }
 358   virtual void WillRefresh(mozilla::TimeStamp aTime) override;
 359
 360   /**
 361    * Compute the time when the currently active refresh driver timer
 362    * will start its next tick.
 363    *
 364    * Expects a non-null default value that is the upper bound of the
 365    * expected deadline. If the next expected deadline is later than
 366    * the default value, the default value is returned.
 367    *
 368    * If we're animating and we have skipped paints a time in the past
 369    * is returned.
 370    *
 371    * If aCheckType is AllVsyncListeners and we're in the parent process,
 372    * which doesn't have a RefreshDriver ticking, but some other process does
 373    * have, the return value is
 374    * (now + refreshrate - layout.idle_period.time_limit) as an approximation
 375    * when something will happen.
 376    * This can be useful check when parent process tries to avoid having too
 377    * long idle periods for example when it is sending input events to an
 378    * active child process.
 379    */
 380   enum IdleCheck { OnlyThisProcessRefreshDriver, AllVsyncListeners };
 381   static mozilla::TimeStamp GetIdleDeadlineHint(mozilla::TimeStamp aDefault,
 382                                                 IdleCheck aCheckType);
 383
 384   /**
 385    * It returns the expected timestamp of the next tick or nothing if the next
 386    * tick is missed.
 387    */
 388   static mozilla::Maybe<mozilla::TimeStamp> GetNextTickHint();
 389
 390   static bool IsRegularRateTimerTicking();
 391
 392   static void DispatchIdleTaskAfterTickUnlessExists(mozilla::Task* aTask);
 393   static void CancelIdleTask(mozilla::Task* aTask);
 394
 395   void NotifyDOMContentLoaded();
 396
 397   // Schedule a refresh so that any delayed events will run soon.
 398   void RunDelayedEventsSoon();
 399
 400   void InitializeTimer() {
 401     MOZ_ASSERT(!mActiveTimer);
 402     EnsureTimerStarted();
 403   }
 404
 405   bool HasPendingTick() const { return mActiveTimer; }
 406
 407   void EnsureIntersectionObservationsUpdateHappens() {
 408     // This is enough to make sure that UpdateIntersectionObservations runs at
 409     // least once. This is presumably the intent of step 5 in [1]:
 410     //
 411     //     Schedule an iteration of the event loop in the root's browsing
 412     //     context.
 413     //
 414     // Though the wording of it is not quite clear to me...
 415     //
 416     // [1]:
 417     // https://w3c.github.io/IntersectionObserver/#dom-intersectionobserver-observe
 418     EnsureTimerStarted();
 419     mNeedToUpdateIntersectionObservations = true;
 420   }
 421
 422   void EnsureResizeObserverUpdateHappens() {
 423     EnsureTimerStarted();
 424     mNeedToUpdateResizeObservers = true;
 425   }
 426
 427   void ScheduleMediaQueryListenerUpdate() {
 428     EnsureTimerStarted();
 429     mMightNeedMediaQueryListenerUpdate = true;
 430   }
 431
 432   void EnsureContentRelevancyUpdateHappens() {
 433     EnsureTimerStarted();
 434     mNeedToUpdateContentRelevancy = true;
 435   }
 436
 437   // Register a composition payload that will be forwarded to the layer manager
 438   // if the current or upcoming refresh tick does a paint.
 439   // If no paint happens, the payload is discarded.
 440   // Should only be called on root refresh drivers.
 441   void RegisterCompositionPayload(
 442       const mozilla::layers::CompositionPayload& aPayload);
 443
 444   enum class TickReasons : uint32_t {
 445     eNone = 0,
 446     eHasObservers = 1 << 0,
 447     eHasImageRequests = 1 << 1,
 448     eNeedsToUpdateIntersectionObservations = 1 << 2,
 449     eNeedsToUpdateContentRelevancy = 1 << 3,
 450     eHasVisualViewportResizeEvents = 1 << 4,
 451     eHasScrollEvents = 1 << 5,
 452     eHasVisualViewportScrollEvents = 1 << 6,
 453     eHasPendingMediaQueryListeners = 1 << 7,
 454     eNeedsToNotifyResizeObservers = 1 << 8,
 455     eRootNeedsMoreTicksForUserInput = 1 << 9,
 456   };
 457
 458   void AddForceNotifyContentfulPaintPresContext(nsPresContext* aPresContext);
 459   void FlushForceNotifyContentfulPaintPresContext();
 460
 461   // Mark that we've just run a tick from vsync, used to throttle 'extra'
 462   // paints to one per vsync (see CanDoExtraTick).
 463   void FinishedVsyncTick() { mAttemptedExtraTickSinceLastVsync = false; }
 464
 465   void CancelFlushAutoFocus(Document* aDocument);
 466
 467  private:
 468   typedef nsTArray<RefPtr<VVPResizeEvent>> VisualViewportResizeEventArray;
 469   typedef nsTArray<RefPtr<mozilla::Runnable>> ScrollEventArray;
 470   typedef nsTArray<RefPtr<VVPScrollEvent>> VisualViewportScrollEventArray;
 471   using RequestTable = nsTHashSet<RefPtr<imgIRequest>>;
 472   struct ImageStartData {
 473     ImageStartData() = default;
 474
 475     mozilla::Maybe<mozilla::TimeStamp> mStartTime;
 476     RequestTable mEntries;
 477   };
 478   typedef nsClassHashtable<nsUint32HashKey, ImageStartData> ImageStartTable;
 479
 480   struct ObserverData {
 481     nsARefreshObserver* mObserver;
 482     const char* mDescription;
 483     mozilla::TimeStamp mRegisterTime;
 484     mozilla::MarkerInnerWindowId mInnerWindowId;
 485     mozilla::UniquePtr<mozilla::ProfileChunkedBuffer> mCause;
 486     mozilla::FlushType mFlushType;
 487
 488     bool operator==(nsARefreshObserver* aObserver) const {
 489       return mObserver == aObserver;
 490     }
 491     operator RefPtr<nsARefreshObserver>() { return mObserver; }
 492   };
 493   using ObserverArray = nsTObserverArray<ObserverData>;
 494   MOZ_CAN_RUN_SCRIPT
 495   void FlushAutoFocusDocuments();
 496   void RunFullscreenSteps();
 497   void DispatchAnimationEvents();
 498   MOZ_CAN_RUN_SCRIPT
 499   void RunFrameRequestCallbacks(mozilla::TimeStamp aNowTime);
 500   void UpdateIntersectionObservations(mozilla::TimeStamp aNowTime);
 501   void UpdateRelevancyOfContentVisibilityAutoFrames();
 502   MOZ_CAN_RUN_SCRIPT void NotifyResizeObservers();
 503   void MaybeIncreaseMeasuredTicksSinceLoading();
 504   void EvaluateMediaQueriesAndReportChanges();
 505
 506   enum class IsExtraTick {
 507     No,
 508     Yes,
 509   };
 510
 511   // Helper for Tick, to call WillRefresh(aNowTime) on each entry in
 512   // mObservers[aIdx] and then potentially do some additional post-notification
 513   // work that's associated with the FlushType corresponding to aIdx.
 514   //
 515   // Returns true on success, or false if one of our calls has destroyed our
 516   // pres context (in which case our callsite Tick() should immediately bail).
 517   MOZ_CAN_RUN_SCRIPT
 518   bool TickObserverArray(uint32_t aIdx, mozilla::TimeStamp aNowTime);
 519
 520   MOZ_CAN_RUN_SCRIPT_BOUNDARY
 521   void Tick(mozilla::VsyncId aId, mozilla::TimeStamp aNowTime,
 522             IsExtraTick aIsExtraTick = IsExtraTick::No);
 523
 524   enum EnsureTimerStartedFlags {
 525     eNone = 0,
 526     eForceAdjustTimer = 1 << 0,
 527     eAllowTimeToGoBackwards = 1 << 1,
 528     eNeverAdjustTimer = 1 << 2,
 529   };
 530   void EnsureTimerStarted(EnsureTimerStartedFlags aFlags = eNone);
 531   void StopTimer();
 532
 533   void UpdateThrottledState();
 534
 535   bool HasObservers() const;
 536   void AppendObserverDescriptionsToString(nsACString& aStr) const;
 537   // Note: This should only be called in the dtor of nsRefreshDriver.
 538   uint32_t ObserverCount() const;
 539   bool HasImageRequests() const;
 540   bool ShouldKeepTimerRunningWhileWaitingForFirstContentfulPaint();
 541   bool ShouldKeepTimerRunningAfterPageLoad();
 542   ObserverArray& ArrayFor(mozilla::FlushType aFlushType);
 543   // Trigger a refresh immediately, if haven't been disconnected or frozen.
 544   void DoRefresh();
 545
 546   // Starts pending image animations, and refreshes ongoing animations.
 547   void UpdateAnimatedImages(mozilla::TimeStamp aPreviousRefresh,
 548                             mozilla::TimeStamp aNowTime);
 549
 550   TickReasons GetReasonsToTick() const;
 551   void AppendTickReasonsToString(TickReasons aReasons, nsACString& aStr) const;
 552
 553   double GetRegularTimerInterval() const;
 554   static double GetThrottledTimerInterval();
 555
 556   static mozilla::TimeDuration GetMinRecomputeVisibilityInterval();
 557
 558   bool HaveFrameRequestCallbacks() const {
 559     return mFrameRequestCallbackDocs.Length() != 0;
 560   }
 561
 562   void FinishedWaitingForTransaction();
 563
 564   /**
 565    * Returns true if we didn't tick on the most recent vsync, but we think
 566    * we could run one now instead in order to reduce latency.
 567    */
 568   bool CanDoCatchUpTick();
 569   /**
 570    * Returns true if we think it's possible to run an repeat tick (between
 571    * vsyncs) to hopefully replace the original tick's paint on the compositor.
 572    * We allow this sometimes for tick requests coming for user input handling
 573    * to reduce latency.
 574    */
 575   bool CanDoExtraTick();
 576
 577   bool AtPendingTransactionLimit() {
 578     return mPendingTransactions.Length() == 2;
 579   }
 580   bool TooManyPendingTransactions() {
 581     return mPendingTransactions.Length() >= 2;
 582   }
 583
 584   mozilla::RefreshDriverTimer* ChooseTimer();
 585   mozilla::RefreshDriverTimer* mActiveTimer;
 586   RefPtr<mozilla::RefreshDriverTimer> mOwnTimer;
 587   mozilla::UniquePtr<mozilla::ProfileChunkedBuffer> mRefreshTimerStartedCause;
 588
 589   // nsPresContext passed in constructor and unset in Disconnect.
 590   mozilla::WeakPtr<nsPresContext> mPresContext;
 591
 592   RefPtr<nsRefreshDriver> mRootRefresh;
 593
 594   // The most recently allocated transaction id.
 595   TransactionId mNextTransactionId;
 596   AutoTArray<TransactionId, 3> mPendingTransactions;
 597
 598   uint32_t mFreezeCount;
 599   uint32_t mUserInputProcessingCount = 0;
 600
 601   // How long we wait between ticks for throttled (which generally means
 602   // non-visible) documents registered with a non-throttled refresh driver.
 603   const mozilla::TimeDuration mThrottledFrameRequestInterval;
 604
 605   // How long we wait, at a minimum, before recomputing approximate frame
 606   // visibility information. This is a minimum because, regardless of this
 607   // interval, we only recompute visibility when we've seen a layout or style
 608   // flush since the last time we did it.
 609   const mozilla::TimeDuration mMinRecomputeVisibilityInterval;
 610
 611   mozilla::UniquePtr<mozilla::ProfileChunkedBuffer> mViewManagerFlushCause;
 612
 613   bool mThrottled : 1;
 614   bool mNeedToRecomputeVisibility : 1;
 615   bool mTestControllingRefreshes : 1;
 616
 617   // These two fields are almost the same, the only difference is that
 618   // mViewManagerFlushIsPending gets cleared right before calling
 619   // ProcessPendingUpdates, and mHasScheduleFlush gets cleared right after
 620   // calling ProcessPendingUpdates. It is important that mHasScheduleFlush
 621   // only gets cleared after, but it's not clear if mViewManagerFlushIsPending
 622   // needs to be cleared before.
 623   bool mViewManagerFlushIsPending : 1;
 624   bool mHasScheduleFlush : 1;
 625
 626   bool mInRefresh : 1;
 627
 628   // True if the refresh driver is suspended waiting for transaction
 629   // id's to be returned and shouldn't do any work during Tick().
 630   bool mWaitingForTransaction : 1;
 631   // True if Tick() was skipped because of mWaitingForTransaction and
 632   // we should schedule a new Tick immediately when resumed instead
 633   // of waiting until the next interval.
 634   bool mSkippedPaints : 1;
 635
 636   // True if view managers should delay any resize request until the
 637   // next tick by the refresh driver. This flag will be reset at the
 638   // start of every tick.
 639   bool mResizeSuppressed : 1;
 640
 641   // True if the next tick should notify DOMContentFlushed.
 642   bool mNotifyDOMContentFlushed : 1;
 643
 644   // True if we need to flush in order to update intersection observations in
 645   // all our documents.
 646   bool mNeedToUpdateIntersectionObservations : 1;
 647
 648   // True if we need to flush in order to update intersection observations in
 649   // all our documents.
 650   bool mNeedToUpdateResizeObservers : 1;
 651
 652   // True if we might need to report media query changes in any of our
 653   // documents.
 654   bool mMightNeedMediaQueryListenerUpdate : 1;
 655
 656   // True if we need to update the relevancy of `content-visibility: auto`
 657   // elements in our documents.
 658   bool mNeedToUpdateContentRelevancy : 1;
 659
 660   // True if we're currently within the scope of Tick() handling a normal
 661   // (timer-driven) tick.
 662   bool mInNormalTick : 1;
 663
 664   // True if we attempted an extra tick (see CanDoExtraTick) since the last
 665   // vsync and thus shouldn't allow another.
 666   bool mAttemptedExtraTickSinceLastVsync : 1;
 667
 668   bool mHasExceededAfterLoadTickPeriod : 1;
 669
 670   bool mHasStartedTimerAtLeastOnce : 1;
 671
 672   mozilla::TimeStamp mMostRecentRefresh;
 673   mozilla::TimeStamp mTickStart;
 674   mozilla::VsyncId mTickVsyncId;
 675   mozilla::TimeStamp mTickVsyncTime;
 676   mozilla::TimeStamp mNextThrottledFrameRequestTick;
 677   mozilla::TimeStamp mNextRecomputeVisibilityTick;
 678   mozilla::TimeStamp mBeforeFirstContentfulPaintTimerRunningLimit;
 679
 680   // separate arrays for each flush type we support
 681   ObserverArray mObservers[4];
 682   // These observers should NOT be included in HasObservers() since that method
 683   // is used to determine whether or not to stop the timer, or restore it when
 684   // thawing the refresh driver. On the other hand these observers are intended
 685   // to be called when the timer is re-started and should not influence its
 686   // starting or stopping.
 687   nsTObserverArray<nsATimerAdjustmentObserver*> mTimerAdjustmentObservers;
 688   nsTArray<mozilla::layers::CompositionPayload> mCompositionPayloads;
 689   RequestTable mRequests;
 690   ImageStartTable mStartTable;
 691   AutoTArray<nsCOMPtr<nsIRunnable>, 16> mEarlyRunners;
 692   VisualViewportResizeEventArray mVisualViewportResizeEvents;
 693   ScrollEventArray mScrollEvents;
 694   VisualViewportScrollEventArray mVisualViewportScrollEvents;
 695
 696   // Scroll events on documents that might have events suppressed.
 697   ScrollEventArray mDelayedScrollEvents;
 698
 699   AutoTArray<mozilla::PresShell*, 16> mResizeEventFlushObservers;
 700   AutoTArray<mozilla::PresShell*, 16> mDelayedResizeEventFlushObservers;
 701   AutoTArray<mozilla::PresShell*, 16> mStyleFlushObservers;
 702   AutoTArray<mozilla::PresShell*, 16> mLayoutFlushObservers;
 703   // nsTArray on purpose, because we want to be able to swap.
 704   nsTArray<Document*> mFrameRequestCallbackDocs;
 705   nsTArray<Document*> mThrottledFrameRequestCallbackDocs;
 706   nsTArray<RefPtr<Document>> mAutoFocusFlushDocuments;
 707   nsTObserverArray<nsAPostRefreshObserver*> mPostRefreshObservers;
 708   nsTArray<mozilla::UniquePtr<mozilla::PendingFullscreenEvent>>
 709       mPendingFullscreenEvents;
 710   AutoTArray<mozilla::AnimationEventDispatcher*, 16>
 711       mAnimationEventFlushObservers;
 712
 713   // nsPresContexts which `NotifyContentfulPaint` have been called,
 714   // however the corresponding paint doesn't come from a regular
 715   // rendering steps(aka tick).
 716   //
 717   // For these nsPresContexts, we invoke
 718   // `FlushForceNotifyContentfulPaintPresContext` in the next tick
 719   // to force notify contentful paint, regardless whether the tick paints
 720   // or not.
 721   nsTArray<mozilla::WeakPtr<nsPresContext>>
 722       mForceNotifyContentfulPaintPresContexts;
 723
 724   void BeginRefreshingImages(RequestTable& aEntries,
 725                              mozilla::TimeStamp aDesired);
 726
 727   friend class mozilla::RefreshDriverTimer;
 728
 729   static void Shutdown();
 730 };
 731
 732 #endif /* !defined(nsRefreshDriver_h_) */