The Tor Browser: gfx/layers/apz/src/AsyncPanZoomController.cpp@97036ab72558 (annotated)

gfx/layers/apz/src/AsyncPanZoomController.cpp@97036ab72558 (annotated)

gfx/layers/apz/src/AsyncPanZoomController.cpp

Tue, 06 Jan 2015 21:39:09 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Tue, 06 Jan 2015 21:39:09 +0100
branch: TOR_BUG_9701
changeset 8: 97036ab72558
permissions: -rw-r--r--

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* vim: set sw=2 ts=8 et 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 <math.h>                       // for fabsf, fabs, atan2
 #include <stdint.h>                     // for uint32_t, uint64_t
 #include <sys/types.h>                  // for int32_t
 #include <algorithm>                    // for max, min
 #include "AnimationCommon.h"            // for ComputedTimingFunction
 #include "AsyncPanZoomController.h"     // for AsyncPanZoomController, etc
 #include "CompositorParent.h"           // for CompositorParent
 #include "FrameMetrics.h"               // for FrameMetrics, etc
 #include "GestureEventListener.h"       // for GestureEventListener
 #include "InputData.h"                  // for MultiTouchInput, etc
 #include "Units.h"                      // for CSSRect, CSSPoint, etc
 #include "UnitTransforms.h"             // for TransformTo
 #include "base/message_loop.h"          // for MessageLoop
 #include "base/task.h"                  // for NewRunnableMethod, etc
 #include "base/tracked.h"               // for FROM_HERE
 #include "gfxPrefs.h"                   // for gfxPrefs
 #include "gfxTypes.h"                   // for gfxFloat
 #include "mozilla/Assertions.h"         // for MOZ_ASSERT, etc
 #include "mozilla/BasicEvents.h"        // for Modifiers, MODIFIER_*
 #include "mozilla/ClearOnShutdown.h"    // for ClearOnShutdown
 #include "mozilla/Constants.h"          // for M_PI
 #include "mozilla/EventForwards.h"      // for nsEventStatus_*
 #include "mozilla/Preferences.h"        // for Preferences
 #include "mozilla/ReentrantMonitor.h"   // for ReentrantMonitorAutoEnter, etc
 #include "mozilla/StaticPtr.h"          // for StaticAutoPtr
 #include "mozilla/TimeStamp.h"          // for TimeDuration, TimeStamp
 #include "mozilla/dom/Touch.h"          // for Touch
 #include "mozilla/gfx/BasePoint.h"      // for BasePoint
 #include "mozilla/gfx/BaseRect.h"       // for BaseRect
 #include "mozilla/gfx/Point.h"          // for Point, RoundedToInt, etc
 #include "mozilla/gfx/Rect.h"           // for RoundedIn
 #include "mozilla/gfx/ScaleFactor.h"    // for ScaleFactor
 #include "mozilla/layers/APZCTreeManager.h"  // for ScrollableLayerGuid
 #include "mozilla/layers/AsyncCompositionManager.h"  // for ViewTransform
 #include "mozilla/layers/Axis.h"        // for AxisX, AxisY, Axis, etc
 #include "mozilla/layers/LayerTransactionParent.h" // for LayerTransactionParent
 #include "mozilla/layers/PCompositorParent.h" // for PCompositorParent
 #include "mozilla/layers/TaskThrottler.h"  // for TaskThrottler
 #include "mozilla/mozalloc.h"           // for operator new, etc
 #include "mozilla/unused.h"             // for unused
 #include "mozilla/FloatingPoint.h"      // for FuzzyEqualsMultiplicative
 #include "nsAlgorithm.h"                // for clamped
 #include "nsAutoPtr.h"                  // for nsRefPtr
 #include "nsCOMPtr.h"                   // for already_AddRefed
 #include "nsDebug.h"                    // for NS_WARNING
 #include "nsIDOMWindowUtils.h"          // for nsIDOMWindowUtils
 #include "nsISupportsImpl.h"            // for MOZ_COUNT_CTOR, etc
 #include "nsMathUtils.h"                // for NS_hypot
 #include "nsPoint.h"                    // for nsIntPoint
 #include "nsStyleConsts.h"
 #include "nsStyleStruct.h"              // for nsTimingFunction
 #include "nsTArray.h"                   // for nsTArray, nsTArray_Impl, etc
 #include "nsThreadUtils.h"              // for NS_IsMainThread
 #include "SharedMemoryBasic.h"          // for SharedMemoryBasic
 // #define APZC_ENABLE_RENDERTRACE
 #define APZC_LOG(...)
 // #define APZC_LOG(...) printf_stderr("APZC: " __VA_ARGS__)
 #define APZC_LOG_FM(fm, prefix, ...) \
   APZC_LOG(prefix ":" \
            " i=(%ld %lld) cb=(%d %d %d %d) rcs=(%.3f %.3f) dp=(%.3f %.3f %.3f %.3f) dpm=(%.3f %.3f %.3f %.3f) um=%d " \
            "v=(%.3f %.3f %.3f %.3f) s=(%.3f %.3f) sr=(%.3f %.3f %.3f %.3f) z=(%.3f %.3f %.3f %.3f) u=(%d %lu)\n", \
            __VA_ARGS__, \
            fm.mPresShellId, fm.GetScrollId(), \
            fm.mCompositionBounds.x, fm.mCompositionBounds.y, fm.mCompositionBounds.width, fm.mCompositionBounds.height, \
            fm.GetRootCompositionSize().width, fm.GetRootCompositionSize().height, \
            fm.mDisplayPort.x, fm.mDisplayPort.y, fm.mDisplayPort.width, fm.mDisplayPort.height, \
            fm.GetDisplayPortMargins().top, fm.GetDisplayPortMargins().right, fm.GetDisplayPortMargins().bottom, fm.GetDisplayPortMargins().left, \
            fm.GetUseDisplayPortMargins() ? 1 : 0, \
            fm.mViewport.x, fm.mViewport.y, fm.mViewport.width, fm.mViewport.height, \
            fm.GetScrollOffset().x, fm.GetScrollOffset().y, \
            fm.mScrollableRect.x, fm.mScrollableRect.y, fm.mScrollableRect.width, fm.mScrollableRect.height, \
            fm.mDevPixelsPerCSSPixel.scale, fm.mResolution.scale, fm.mCumulativeResolution.scale, fm.GetZoom().scale, \
            fm.GetScrollOffsetUpdated(), fm.GetScrollGeneration()); \
 // Static helper functions
 namespace {
 int32_t
 WidgetModifiersToDOMModifiers(mozilla::Modifiers aModifiers)
 {
   int32_t result = 0;
   if (aModifiers & mozilla::MODIFIER_SHIFT) {
     result |= nsIDOMWindowUtils::MODIFIER_SHIFT;
   }
   if (aModifiers & mozilla::MODIFIER_CONTROL) {
     result |= nsIDOMWindowUtils::MODIFIER_CONTROL;
   }
   if (aModifiers & mozilla::MODIFIER_ALT) {
     result |= nsIDOMWindowUtils::MODIFIER_ALT;
   }
   if (aModifiers & mozilla::MODIFIER_META) {
     result |= nsIDOMWindowUtils::MODIFIER_META;
   }
   if (aModifiers & mozilla::MODIFIER_ALTGRAPH) {
     result |= nsIDOMWindowUtils::MODIFIER_ALTGRAPH;
   }
   if (aModifiers & mozilla::MODIFIER_CAPSLOCK) {
     result |= nsIDOMWindowUtils::MODIFIER_CAPSLOCK;
   }
   if (aModifiers & mozilla::MODIFIER_FN) {
     result |= nsIDOMWindowUtils::MODIFIER_FN;
   }
   if (aModifiers & mozilla::MODIFIER_NUMLOCK) {
     result |= nsIDOMWindowUtils::MODIFIER_NUMLOCK;
   }
   if (aModifiers & mozilla::MODIFIER_SCROLLLOCK) {
     result |= nsIDOMWindowUtils::MODIFIER_SCROLLLOCK;
   }
   if (aModifiers & mozilla::MODIFIER_SYMBOLLOCK) {
     result |= nsIDOMWindowUtils::MODIFIER_SYMBOLLOCK;
   }
   if (aModifiers & mozilla::MODIFIER_OS) {
     result |= nsIDOMWindowUtils::MODIFIER_OS;
   }
   return result;
 }
 }
 using namespace mozilla::css;
 namespace mozilla {
 namespace layers {
 typedef mozilla::layers::AllowedTouchBehavior AllowedTouchBehavior;
 typedef GeckoContentController::APZStateChange APZStateChange;
 /*
  * The following prefs are used to control the behaviour of the APZC.
  * The default values are provided in gfxPrefs.h.
  *
  * "apz.allow-checkerboarding"
  * Pref that allows or disallows checkerboarding
  *
  * "apz.asyncscroll.throttle"
  * The time period in ms that throttles mozbrowserasyncscroll event.
  *
  * "apz.asyncscroll.timeout"
  * The timeout in ms for mAsyncScrollTimeoutTask delay task.
  *
  * "apz.axis_lock_mode"
  * The preferred axis locking style. See AxisLockMode for possible values.
  *
  * "apz.content_response_timeout"
  * Amount of time before we timeout response from content. For example, if
  * content is being unruly/slow and we don't get a response back within this
  * time, we will just pretend that content did not preventDefault any touch
  * events we dispatched to it.
  *
  * "apz.cross_slide_enabled"
  * Pref that enables integration with the Metro "cross-slide" gesture.
  *
  * "apz.enlarge_displayport_when_clipped"
  * Pref that enables enlarging of the displayport along one axis when the
  * generated displayport's size is beyond that of the scrollable rect on the
  * opposite axis.
  *
  * "apz.fling_friction"
  * Amount of friction applied during flings.
  *
  * "apz.fling_repaint_interval"
  * Maximum amount of time flinging before sending a viewport change. This will
  * asynchronously repaint the page.
  *
  * "apz.fling_stopped_threshold"
  * When flinging, if the velocity goes below this number, we just stop the
  * animation completely. This is to prevent asymptotically approaching 0
  * velocity and rerendering unnecessarily.
  *
  * "apz.max_velocity_inches_per_ms"
  * Maximum velocity in inches per millisecond.  Velocity will be capped at this
  * value if a faster fling occurs.  Negative values indicate unlimited velocity.
  *
  * "apz.max_velocity_queue_size"
  * Maximum size of velocity queue. The queue contains last N velocity records.
  * On touch end we calculate the average velocity in order to compensate
  * touch/mouse drivers misbehaviour.
  *
  * "apz.min_skate_speed"
  * Minimum amount of speed along an axis before we switch to "skate" multipliers
  * rather than using the "stationary" multipliers.
  *
  * "apz.num_paint_duration_samples"
  * Number of samples to store of how long it took to paint after the previous
  * requests.
  *
  * "apz.pan_repaint_interval"
  * Maximum amount of time while panning before sending a viewport change. This
  * will asynchronously repaint the page. It is also forced when panning stops.
  *
  * "apz.touch_start_tolerance"
  * Constant describing the tolerance in distance we use, multiplied by the
  * device DPI, before we start panning the screen. This is to prevent us from
  * accidentally processing taps as touch moves, and from very short/accidental
  * touches moving the screen.
  *
  * "apz.use_paint_duration"
  * Whether or not to use the estimated paint duration as a factor when projecting
  * the displayport in the direction of scrolling. If this value is set to false,
  * a constant 50ms paint time is used; the projection can be scaled as desired
  * using the apz.velocity_bias pref below.
  *
  * "apz.velocity_bias"
  * How much to adjust the displayport in the direction of scrolling. This value
  * is multiplied by the velocity and added to the displayport offset.
  *
  * "apz.x_skate_size_multiplier", "apz.y_skate_size_multiplier"
  * The multiplier we apply to the displayport size if it is skating (current
  * velocity is above apz.min_skate_speed). We prefer to increase the size of the
  * Y axis because it is more natural in the case that a user is reading a page
  * that scrolls up/down. Note that one, both or neither of these may be used
  * at any instant.
  * In general we want apz.[xy]_skate_size_multiplier to be smaller than the corresponding
  * stationary size multiplier because when panning fast we would like to paint
  * less and get faster, more predictable paint times. When panning slowly we
  * can afford to paint more even though it's slower.
  *
  * "apz.x_stationary_size_multiplier", "apz.y_stationary_size_multiplier"
  * The multiplier we apply to the displayport size if it is not skating (see
  * documentation for the skate size multipliers above).
  */
 /**
  * Default touch behavior (is used when not touch behavior is set).
  */
 static const uint32_t DefaultTouchBehavior = AllowedTouchBehavior::VERTICAL_PAN |
                                              AllowedTouchBehavior::HORIZONTAL_PAN |
                                              AllowedTouchBehavior::PINCH_ZOOM |
                                              AllowedTouchBehavior::DOUBLE_TAP_ZOOM;
 /**
  * Angle from axis within which we stay axis-locked
  */
 static const double AXIS_LOCK_ANGLE = M_PI / 6.0; // 30 degrees
 /**
  * The distance in inches the user must pan before axis lock can be broken
  */
 static const float AXIS_BREAKOUT_THRESHOLD = 1.0f/32.0f;
 /**
  * The angle at which axis lock can be broken
  */
 static const double AXIS_BREAKOUT_ANGLE = M_PI / 8.0; // 22.5 degrees
 /**
  * Angle from axis to the line drawn by pan move.
  * If angle is less than this value we can assume that panning
  * can be done in allowed direction (horizontal or vertical).
  * Currently used only for touch-action css property stuff and was
  * added to keep behavior consistent with IE.
  */
 static const double ALLOWED_DIRECT_PAN_ANGLE = M_PI / 3.0; // 60 degrees
 /**
  * Duration of a zoom to animation.
  */
 static const TimeDuration ZOOM_TO_DURATION = TimeDuration::FromSeconds(0.25);
 /**
  * Computed time function used for sampling frames of a zoom to animation.
  */
 StaticAutoPtr<ComputedTimingFunction> gComputedTimingFunction;
 /**
  * Maximum zoom amount, always used, even if a page asks for higher.
  */
 static const CSSToScreenScale MAX_ZOOM(8.0f);
 /**
  * Minimum zoom amount, always used, even if a page asks for lower.
  */
 static const CSSToScreenScale MIN_ZOOM(0.125f);
 /**
  * Is aAngle within the given threshold of the horizontal axis?
  * @param aAngle an angle in radians in the range [0, pi]
  * @param aThreshold an angle in radians in the range [0, pi/2]
  */
 static bool IsCloseToHorizontal(float aAngle, float aThreshold)
 {
   return (aAngle < aThreshold || aAngle > (M_PI - aThreshold));
 }
 // As above, but for the vertical axis.
 static bool IsCloseToVertical(float aAngle, float aThreshold)
 {
   return (fabs(aAngle - (M_PI / 2)) < aThreshold);
 }
 template <typename Units>
 static bool IsZero(const gfx::PointTyped<Units>& aPoint)
 {
   return FuzzyEqualsMultiplicative(aPoint.x, 0.0f)
       && FuzzyEqualsMultiplicative(aPoint.y, 0.0f);
 }
 static inline void LogRendertraceRect(const ScrollableLayerGuid& aGuid, const char* aDesc, const char* aColor, const CSSRect& aRect)
 {
 #ifdef APZC_ENABLE_RENDERTRACE
   static const TimeStamp sRenderStart = TimeStamp::Now();
   TimeDuration delta = TimeStamp::Now() - sRenderStart;
   printf_stderr("(%llu,%lu,%llu)%s RENDERTRACE %f rect %s %f %f %f %f\n",
     aGuid.mLayersId, aGuid.mPresShellId, aGuid.GetScrollId(),
     aDesc, delta.ToMilliseconds(), aColor,
     aRect.x, aRect.y, aRect.width, aRect.height);
 #endif
 }
 static TimeStamp sFrameTime;
 // Counter used to give each APZC a unique id
 static uint32_t sAsyncPanZoomControllerCount = 0;
 static TimeStamp
 GetFrameTime() {
   if (sFrameTime.IsNull()) {
     return TimeStamp::Now();
   }
   return sFrameTime;
 }
 class FlingAnimation: public AsyncPanZoomAnimation {
 public:
   FlingAnimation(AsyncPanZoomController& aApzc)
     : AsyncPanZoomAnimation(TimeDuration::FromMilliseconds(gfxPrefs::APZFlingRepaintInterval()))
     , mApzc(aApzc)
   {}
   /**
    * Advances a fling by an interpolated amount based on the passed in |aDelta|.
    * This should be called whenever sampling the content transform for this
    * frame. Returns true if the fling animation should be advanced by one frame,
    * or false if there is no fling or the fling has ended.
    */
   virtual bool Sample(FrameMetrics& aFrameMetrics,
                       const TimeDuration& aDelta);
 private:
   AsyncPanZoomController& mApzc;
 };
 class ZoomAnimation: public AsyncPanZoomAnimation {
 public:
   ZoomAnimation(CSSPoint aStartOffset, CSSToScreenScale aStartZoom,
                 CSSPoint aEndOffset, CSSToScreenScale aEndZoom)
     : mStartOffset(aStartOffset)
     , mStartZoom(aStartZoom)
     , mEndOffset(aEndOffset)
     , mEndZoom(aEndZoom)
   {}
   virtual bool Sample(FrameMetrics& aFrameMetrics,
                       const TimeDuration& aDelta);
 private:
   TimeDuration mDuration;
   // Old metrics from before we started a zoom animation. This is only valid
   // when we are in the "ANIMATED_ZOOM" state. This is used so that we can
   // interpolate between the start and end frames. We only use the
   // |mViewportScrollOffset| and |mResolution| fields on this.
   CSSPoint mStartOffset;
   CSSToScreenScale mStartZoom;
   // Target metrics for a zoom to animation. This is only valid when we are in
   // the "ANIMATED_ZOOM" state. We only use the |mViewportScrollOffset| and
   // |mResolution| fields on this.
   CSSPoint mEndOffset;
   CSSToScreenScale mEndZoom;
 };
 void
 AsyncPanZoomController::SetFrameTime(const TimeStamp& aTime) {
   sFrameTime = aTime;
 }
 /*static*/ void
 AsyncPanZoomController::InitializeGlobalState()
 {
   MOZ_ASSERT(NS_IsMainThread());
   static bool sInitialized = false;
   if (sInitialized)
     return;
   sInitialized = true;
   gComputedTimingFunction = new ComputedTimingFunction();
   gComputedTimingFunction->Init(
     nsTimingFunction(NS_STYLE_TRANSITION_TIMING_FUNCTION_EASE));
   ClearOnShutdown(&gComputedTimingFunction);
 }
 AsyncPanZoomController::AsyncPanZoomController(uint64_t aLayersId,
                                                APZCTreeManager* aTreeManager,
                                                GeckoContentController* aGeckoContentController,
                                                GestureBehavior aGestures)
   :  mLayersId(aLayersId),
      mCrossProcessCompositorParent(nullptr),
      mPaintThrottler(GetFrameTime()),
      mGeckoContentController(aGeckoContentController),
      mRefPtrMonitor("RefPtrMonitor"),
      mMonitor("AsyncPanZoomController"),
      mTouchActionPropertyEnabled(gfxPrefs::TouchActionEnabled()),
      mContentResponseTimeoutTask(nullptr),
      mX(MOZ_THIS_IN_INITIALIZER_LIST()),
      mY(MOZ_THIS_IN_INITIALIZER_LIST()),
      mPanDirRestricted(false),
      mZoomConstraints(false, false, MIN_ZOOM, MAX_ZOOM),
      mLastSampleTime(GetFrameTime()),
      mState(NOTHING),
      mLastAsyncScrollTime(GetFrameTime()),
      mLastAsyncScrollOffset(0, 0),
      mCurrentAsyncScrollOffset(0, 0),
      mAsyncScrollTimeoutTask(nullptr),
      mHandlingTouchQueue(false),
      mTreeManager(aTreeManager),
      mScrollParentId(FrameMetrics::NULL_SCROLL_ID),
      mAPZCId(sAsyncPanZoomControllerCount++),
      mSharedFrameMetricsBuffer(nullptr),
      mSharedLock(nullptr)
 {
   MOZ_COUNT_CTOR(AsyncPanZoomController);
   if (aGestures == USE_GESTURE_DETECTOR) {
     mGestureEventListener = new GestureEventListener(this);
   }
 }
 AsyncPanZoomController::~AsyncPanZoomController() {
   PCompositorParent* compositor =
     (mCrossProcessCompositorParent ? mCrossProcessCompositorParent : mCompositorParent.get());
   // Only send the release message if the SharedFrameMetrics has been created.
   if (compositor && mSharedFrameMetricsBuffer) {
     unused << compositor->SendReleaseSharedCompositorFrameMetrics(mFrameMetrics.GetScrollId(), mAPZCId);
   }
   delete mSharedFrameMetricsBuffer;
   delete mSharedLock;
   MOZ_COUNT_DTOR(AsyncPanZoomController);
 }
 already_AddRefed<GeckoContentController>
 AsyncPanZoomController::GetGeckoContentController() {
   MonitorAutoLock lock(mRefPtrMonitor);
   nsRefPtr<GeckoContentController> controller = mGeckoContentController;
   return controller.forget();
 }
 already_AddRefed<GestureEventListener>
 AsyncPanZoomController::GetGestureEventListener() {
   MonitorAutoLock lock(mRefPtrMonitor);
   nsRefPtr<GestureEventListener> listener = mGestureEventListener;
   return listener.forget();
 }
 void
 AsyncPanZoomController::Destroy()
 {
   { // scope the lock
     MonitorAutoLock lock(mRefPtrMonitor);
     mGeckoContentController = nullptr;
     mGestureEventListener = nullptr;
   }
   mPrevSibling = nullptr;
   mLastChild = nullptr;
   mParent = nullptr;
   mTreeManager = nullptr;
 }
 bool
 AsyncPanZoomController::IsDestroyed()
 {
   return mTreeManager == nullptr;
 }
 /* static */float
 AsyncPanZoomController::GetTouchStartTolerance()
 {
   return (gfxPrefs::APZTouchStartTolerance() * APZCTreeManager::GetDPI());
 }
 /* static */AsyncPanZoomController::AxisLockMode AsyncPanZoomController::GetAxisLockMode()
 {
   return static_cast<AxisLockMode>(gfxPrefs::APZAxisLockMode());
 }
 nsEventStatus AsyncPanZoomController::ReceiveInputEvent(const InputData& aEvent) {
   if (aEvent.mInputType == MULTITOUCH_INPUT &&
       aEvent.AsMultiTouchInput().mType == MultiTouchInput::MULTITOUCH_START) {
     // Starting a new touch block, clear old touch block state.
     mTouchBlockState = TouchBlockState();
   }
   // If we may have touch listeners and touch action property is enabled, we
   // enable the machinery that allows touch listeners to preventDefault any touch inputs
   // and also waits for the allowed touch behavior values to be received from the outside.
   // This should not happen unless there are actually touch listeners and touch-action property
   // enable as it introduces potentially unbounded lag because it causes a round-trip through
   // content.  Usually, if content is responding in a timely fashion, this only introduces a
   // nearly constant few hundred ms of lag.
   if (mFrameMetrics.mMayHaveTouchListeners && aEvent.mInputType == MULTITOUCH_INPUT &&
       (mState == NOTHING || mState == TOUCHING || IsPanningState(mState))) {
     const MultiTouchInput& multiTouchInput = aEvent.AsMultiTouchInput();
     if (multiTouchInput.mType == MultiTouchInput::MULTITOUCH_START) {
       SetState(WAITING_CONTENT_RESPONSE);
     }
   }
   if (mState == WAITING_CONTENT_RESPONSE || mHandlingTouchQueue) {
     if (aEvent.mInputType == MULTITOUCH_INPUT) {
       const MultiTouchInput& multiTouchInput = aEvent.AsMultiTouchInput();
       mTouchQueue.AppendElement(multiTouchInput);
       SetContentResponseTimer();
     }
     return nsEventStatus_eIgnore;
   }
   return HandleInputEvent(aEvent);
 }
 nsEventStatus AsyncPanZoomController::HandleInputEvent(const InputData& aEvent) {
   nsEventStatus rv = nsEventStatus_eIgnore;
   switch (aEvent.mInputType) {
   case MULTITOUCH_INPUT: {
     const MultiTouchInput& multiTouchInput = aEvent.AsMultiTouchInput();
     nsRefPtr<GestureEventListener> listener = GetGestureEventListener();
     if (listener) {
       rv = listener->HandleInputEvent(multiTouchInput);
       if (rv == nsEventStatus_eConsumeNoDefault) {
         return rv;
       }
     }
     switch (multiTouchInput.mType) {
       case MultiTouchInput::MULTITOUCH_START: rv = OnTouchStart(multiTouchInput); break;
       case MultiTouchInput::MULTITOUCH_MOVE: rv = OnTouchMove(multiTouchInput); break;
       case MultiTouchInput::MULTITOUCH_END: rv = OnTouchEnd(multiTouchInput); break;
       case MultiTouchInput::MULTITOUCH_CANCEL: rv = OnTouchCancel(multiTouchInput); break;
       default: NS_WARNING("Unhandled multitouch"); break;
     }
     break;
   }
   default: NS_WARNING("Unhandled input event"); break;
   }
   mLastEventTime = aEvent.mTime;
   return rv;
 }
 nsEventStatus AsyncPanZoomController::HandleGestureEvent(const InputData& aEvent)
 {
   nsEventStatus rv = nsEventStatus_eIgnore;
   switch (aEvent.mInputType) {
   case PINCHGESTURE_INPUT: {
     const PinchGestureInput& pinchGestureInput = aEvent.AsPinchGestureInput();
     switch (pinchGestureInput.mType) {
       case PinchGestureInput::PINCHGESTURE_START: rv = OnScaleBegin(pinchGestureInput); break;
       case PinchGestureInput::PINCHGESTURE_SCALE: rv = OnScale(pinchGestureInput); break;
       case PinchGestureInput::PINCHGESTURE_END: rv = OnScaleEnd(pinchGestureInput); break;
       default: NS_WARNING("Unhandled pinch gesture"); break;
     }
     break;
   }
   case TAPGESTURE_INPUT: {
     const TapGestureInput& tapGestureInput = aEvent.AsTapGestureInput();
     switch (tapGestureInput.mType) {
       case TapGestureInput::TAPGESTURE_LONG: rv = OnLongPress(tapGestureInput); break;
       case TapGestureInput::TAPGESTURE_LONG_UP: rv = OnLongPressUp(tapGestureInput); break;
       case TapGestureInput::TAPGESTURE_UP: rv = OnSingleTapUp(tapGestureInput); break;
       case TapGestureInput::TAPGESTURE_CONFIRMED: rv = OnSingleTapConfirmed(tapGestureInput); break;
       case TapGestureInput::TAPGESTURE_DOUBLE: rv = OnDoubleTap(tapGestureInput); break;
       case TapGestureInput::TAPGESTURE_CANCEL: rv = OnCancelTap(tapGestureInput); break;
       default: NS_WARNING("Unhandled tap gesture"); break;
     }
     break;
   }
   default: NS_WARNING("Unhandled input event"); break;
   }
   mLastEventTime = aEvent.mTime;
   return rv;
 }
 nsEventStatus AsyncPanZoomController::OnTouchStart(const MultiTouchInput& aEvent) {
   APZC_LOG("%p got a touch-start in state %d\n", this, mState);
   mPanDirRestricted = false;
   ScreenIntPoint point = GetFirstTouchScreenPoint(aEvent);
   switch (mState) {
     case ANIMATING_ZOOM:
       // We just interrupted a double-tap animation, so force a redraw in case
       // this touchstart is just a tap that doesn't end up triggering a redraw.
       {
         ReentrantMonitorAutoEnter lock(mMonitor);
         RequestContentRepaint();
         ScheduleComposite();
         UpdateSharedCompositorFrameMetrics();
       }
       // Fall through.
     case FLING:
       CancelAnimation();
       // Fall through.
     case NOTHING: {
       mX.StartTouch(point.x);
       mY.StartTouch(point.y);
       APZCTreeManager* treeManagerLocal = mTreeManager;
       nsRefPtr<GeckoContentController> controller = GetGeckoContentController();
       if (treeManagerLocal && controller) {
         bool touchCanBePan = treeManagerLocal->CanBePanned(this);
         controller->NotifyAPZStateChange(
             GetGuid(), APZStateChange::StartTouch, touchCanBePan);
       }
       SetState(TOUCHING);
       break;
     }
     case TOUCHING:
     case PANNING:
     case PANNING_LOCKED_X:
     case PANNING_LOCKED_Y:
     case CROSS_SLIDING_X:
     case CROSS_SLIDING_Y:
     case PINCHING:
     case WAITING_CONTENT_RESPONSE:
       NS_WARNING("Received impossible touch in OnTouchStart");
       break;
     default:
       NS_WARNING("Unhandled case in OnTouchStart");
       break;
   }
   return nsEventStatus_eConsumeNoDefault;
 }
 nsEventStatus AsyncPanZoomController::OnTouchMove(const MultiTouchInput& aEvent) {
   APZC_LOG("%p got a touch-move in state %d\n", this, mState);
   switch (mState) {
     case FLING:
     case NOTHING:
     case ANIMATING_ZOOM:
       // May happen if the user double-taps and drags without lifting after the
       // second tap. Ignore the move if this happens.
       return nsEventStatus_eIgnore;
     case CROSS_SLIDING_X:
     case CROSS_SLIDING_Y:
       // While cross-sliding, we don't want to consume any touchmove events for
       // panning or zooming, and let the caller handle them instead.
       return nsEventStatus_eIgnore;
     case TOUCHING: {
       float panThreshold = GetTouchStartTolerance();
       UpdateWithTouchAtDevicePoint(aEvent);
       if (PanDistance() < panThreshold) {
         return nsEventStatus_eIgnore;
       }
       if (mTouchActionPropertyEnabled &&
           (GetTouchBehavior(0) & AllowedTouchBehavior::VERTICAL_PAN) &&
           (GetTouchBehavior(0) & AllowedTouchBehavior::HORIZONTAL_PAN)) {
         // User tries to trigger a touch behavior. If allowed touch behavior is vertical pan
         // + horizontal pan (touch-action value is equal to AUTO) we can return ConsumeNoDefault
         // status immediately to trigger cancel event further. It should happen independent of
         // the parent type (whether it is scrolling or not).
         StartPanning(aEvent);
         return nsEventStatus_eConsumeNoDefault;
       }
       return StartPanning(aEvent);
     }
     case PANNING:
     case PANNING_LOCKED_X:
     case PANNING_LOCKED_Y:
       TrackTouch(aEvent);
       return nsEventStatus_eConsumeNoDefault;
     case PINCHING:
       // The scale gesture listener should have handled this.
       NS_WARNING("Gesture listener should have handled pinching in OnTouchMove.");
       return nsEventStatus_eIgnore;
     case WAITING_CONTENT_RESPONSE:
       NS_WARNING("Received impossible touch in OnTouchMove");
       break;
   }
   return nsEventStatus_eConsumeNoDefault;
 }
 nsEventStatus AsyncPanZoomController::OnTouchEnd(const MultiTouchInput& aEvent) {
   APZC_LOG("%p got a touch-end in state %d\n", this, mState);
   OnTouchEndOrCancel();
   // In case no touch behavior triggered previously we can avoid sending
   // scroll events or requesting content repaint. This condition is added
   // to make tests consistent - in case touch-action is NONE (and therefore
   // no pans/zooms can be performed) we expected neither scroll or repaint
   // events.
   if (mState != NOTHING) {
     ReentrantMonitorAutoEnter lock(mMonitor);
     SendAsyncScrollEvent();
   }
   switch (mState) {
   case FLING:
     // Should never happen.
     NS_WARNING("Received impossible touch end in OnTouchEnd.");
     // Fall through.
   case ANIMATING_ZOOM:
   case NOTHING:
     // May happen if the user double-taps and drags without lifting after the
     // second tap. Ignore if this happens.
     return nsEventStatus_eIgnore;
   case TOUCHING:
   case CROSS_SLIDING_X:
   case CROSS_SLIDING_Y:
     SetState(NOTHING);
     return nsEventStatus_eIgnore;
   case PANNING:
   case PANNING_LOCKED_X:
   case PANNING_LOCKED_Y:
     {
       // Make a local copy of the tree manager pointer and check if it's not
       // null before calling FlushRepaintsForOverscrollHandoffChain().
       // This is necessary because Destroy(), which nulls out mTreeManager,
       // could be called concurrently.
       APZCTreeManager* treeManagerLocal = mTreeManager;
       if (treeManagerLocal) {
         if (!treeManagerLocal->FlushRepaintsForOverscrollHandoffChain()) {
           NS_WARNING("Overscroll handoff chain was empty during panning! This should not be the case.");
           // Graceful handling of error condition
           FlushRepaintForOverscrollHandoff();
         }
       }
     }
     mX.EndTouch();
     mY.EndTouch();
     SetState(FLING);
     StartAnimation(new FlingAnimation(*this));
     return nsEventStatus_eConsumeNoDefault;
   case PINCHING:
     SetState(NOTHING);
     // Scale gesture listener should have handled this.
     NS_WARNING("Gesture listener should have handled pinching in OnTouchEnd.");
     return nsEventStatus_eIgnore;
   case WAITING_CONTENT_RESPONSE:
     NS_WARNING("Received impossible touch in OnTouchEnd");
     break;
   }
   return nsEventStatus_eConsumeNoDefault;
 }
 nsEventStatus AsyncPanZoomController::OnTouchCancel(const MultiTouchInput& aEvent) {
   APZC_LOG("%p got a touch-cancel in state %d\n", this, mState);
   OnTouchEndOrCancel();
   SetState(NOTHING);
   return nsEventStatus_eConsumeNoDefault;
 }
 nsEventStatus AsyncPanZoomController::OnScaleBegin(const PinchGestureInput& aEvent) {
   APZC_LOG("%p got a scale-begin in state %d\n", this, mState);
   if (!TouchActionAllowPinchZoom()) {
     return nsEventStatus_eIgnore;
   }
   if (!mZoomConstraints.mAllowZoom) {
     return nsEventStatus_eConsumeNoDefault;
   }
   SetState(PINCHING);
   mLastZoomFocus = ToParentLayerCoords(aEvent.mFocusPoint) - mFrameMetrics.mCompositionBounds.TopLeft();
   return nsEventStatus_eConsumeNoDefault;
 }
 nsEventStatus AsyncPanZoomController::OnScale(const PinchGestureInput& aEvent) {
   APZC_LOG("%p got a scale in state %d\n", this, mState);
   if (mState != PINCHING) {
     return nsEventStatus_eConsumeNoDefault;
   }
   float prevSpan = aEvent.mPreviousSpan;
   if (fabsf(prevSpan) <= EPSILON || fabsf(aEvent.mCurrentSpan) <= EPSILON) {
     // We're still handling it; we've just decided to throw this event away.
     return nsEventStatus_eConsumeNoDefault;
   }
   float spanRatio = aEvent.mCurrentSpan / aEvent.mPreviousSpan;
   {
     ReentrantMonitorAutoEnter lock(mMonitor);
     CSSToParentLayerScale userZoom = mFrameMetrics.GetZoomToParent();
     ParentLayerPoint focusPoint = ToParentLayerCoords(aEvent.mFocusPoint) - mFrameMetrics.mCompositionBounds.TopLeft();
     CSSPoint cssFocusPoint = focusPoint / userZoom;
     CSSPoint focusChange = (mLastZoomFocus - focusPoint) / userZoom;
     // If displacing by the change in focus point will take us off page bounds,
     // then reduce the displacement such that it doesn't.
     if (mX.DisplacementWillOverscroll(focusChange.x) != Axis::OVERSCROLL_NONE) {
       focusChange.x -= mX.DisplacementWillOverscrollAmount(focusChange.x);
     }
     if (mY.DisplacementWillOverscroll(focusChange.y) != Axis::OVERSCROLL_NONE) {
       focusChange.y -= mY.DisplacementWillOverscrollAmount(focusChange.y);
     }
     ScrollBy(focusChange);
     // When we zoom in with focus, we can zoom too much towards the boundaries
     // that we actually go over them. These are the needed displacements along
     // either axis such that we don't overscroll the boundaries when zooming.
     CSSPoint neededDisplacement;
     CSSToParentLayerScale realMinZoom = mZoomConstraints.mMinZoom * mFrameMetrics.mTransformScale;
     CSSToParentLayerScale realMaxZoom = mZoomConstraints.mMaxZoom * mFrameMetrics.mTransformScale;
     realMinZoom.scale = std::max(realMinZoom.scale,
                                  mFrameMetrics.mCompositionBounds.width / mFrameMetrics.mScrollableRect.width);
     realMinZoom.scale = std::max(realMinZoom.scale,
                                  mFrameMetrics.mCompositionBounds.height / mFrameMetrics.mScrollableRect.height);
     if (realMaxZoom < realMinZoom) {
       realMaxZoom = realMinZoom;
     }
     bool doScale = (spanRatio > 1.0 && userZoom < realMaxZoom) ||
                    (spanRatio < 1.0 && userZoom > realMinZoom);
     if (doScale) {
       spanRatio = clamped(spanRatio,
                           realMinZoom.scale / userZoom.scale,
                           realMaxZoom.scale / userZoom.scale);
       // Note that the spanRatio here should never put us into OVERSCROLL_BOTH because
       // up above we clamped it.
       neededDisplacement.x = -mX.ScaleWillOverscrollAmount(spanRatio, cssFocusPoint.x);
       neededDisplacement.y = -mY.ScaleWillOverscrollAmount(spanRatio, cssFocusPoint.y);
       ScaleWithFocus(spanRatio, cssFocusPoint);
       if (neededDisplacement != CSSPoint()) {
         ScrollBy(neededDisplacement);
       }
       ScheduleComposite();
       // We don't want to redraw on every scale, so don't use
       // RequestContentRepaint()
       UpdateSharedCompositorFrameMetrics();
     }
     mLastZoomFocus = focusPoint;
   }
   return nsEventStatus_eConsumeNoDefault;
 }
 nsEventStatus AsyncPanZoomController::OnScaleEnd(const PinchGestureInput& aEvent) {
   APZC_LOG("%p got a scale-end in state %d\n", this, mState);
   SetState(NOTHING);
   {
     ReentrantMonitorAutoEnter lock(mMonitor);
     ScheduleComposite();
     RequestContentRepaint();
     UpdateSharedCompositorFrameMetrics();
   }
   return nsEventStatus_eConsumeNoDefault;
 }
 bool
 AsyncPanZoomController::ConvertToGecko(const ScreenPoint& aPoint, CSSPoint* aOut)
 {
   APZCTreeManager* treeManagerLocal = mTreeManager;
   if (treeManagerLocal) {
     gfx3DMatrix transformToApzc;
     gfx3DMatrix transformToGecko;
     treeManagerLocal->GetInputTransforms(this, transformToApzc, transformToGecko);
     gfxPoint result = transformToGecko.Transform(gfxPoint(aPoint.x, aPoint.y));
     // NOTE: This isn't *quite* LayoutDevicePoint, we just don't have a name
     // for this coordinate space and it maps the closest to LayoutDevicePoint.
     LayoutDevicePoint layoutPoint = LayoutDevicePoint(result.x, result.y);
     { // scoped lock to access mFrameMetrics
       ReentrantMonitorAutoEnter lock(mMonitor);
       *aOut = layoutPoint / mFrameMetrics.mDevPixelsPerCSSPixel;
     }
     return true;
   }
   return false;
 }
 nsEventStatus AsyncPanZoomController::OnLongPress(const TapGestureInput& aEvent) {
   APZC_LOG("%p got a long-press in state %d\n", this, mState);
   nsRefPtr<GeckoContentController> controller = GetGeckoContentController();
   if (controller) {
     int32_t modifiers = WidgetModifiersToDOMModifiers(aEvent.modifiers);
     CSSPoint geckoScreenPoint;
     if (ConvertToGecko(aEvent.mPoint, &geckoScreenPoint)) {
       SetState(WAITING_CONTENT_RESPONSE);
       SetContentResponseTimer();
       controller->HandleLongTap(geckoScreenPoint, modifiers, GetGuid());
       return nsEventStatus_eConsumeNoDefault;
     }
   }
   return nsEventStatus_eIgnore;
 }
 nsEventStatus AsyncPanZoomController::OnLongPressUp(const TapGestureInput& aEvent) {
   APZC_LOG("%p got a long-tap-up in state %d\n", this, mState);
   nsRefPtr<GeckoContentController> controller = GetGeckoContentController();
   if (controller) {
     int32_t modifiers = WidgetModifiersToDOMModifiers(aEvent.modifiers);
     CSSPoint geckoScreenPoint;
     if (ConvertToGecko(aEvent.mPoint, &geckoScreenPoint)) {
       controller->HandleLongTapUp(geckoScreenPoint, modifiers, GetGuid());
       return nsEventStatus_eConsumeNoDefault;
     }
   }
   return nsEventStatus_eIgnore;
 }
 nsEventStatus AsyncPanZoomController::GenerateSingleTap(const ScreenIntPoint& aPoint, mozilla::Modifiers aModifiers) {
   nsRefPtr<GeckoContentController> controller = GetGeckoContentController();
   if (controller) {
     CSSPoint geckoScreenPoint;
     if (ConvertToGecko(aPoint, &geckoScreenPoint)) {
       int32_t modifiers = WidgetModifiersToDOMModifiers(aModifiers);
       // Because this may be being running as part of APZCTreeManager::ReceiveInputEvent,
       // calling controller->HandleSingleTap directly might mean that content receives
       // the single tap message before the corresponding touch-up. To avoid that we
       // schedule the singletap message to run on the next spin of the event loop.
       // See bug 965381 for the issue this was causing.
       controller->PostDelayedTask(
         NewRunnableMethod(controller.get(), &GeckoContentController::HandleSingleTap,
                           geckoScreenPoint, modifiers, GetGuid()),
 );
       mTouchBlockState.mSingleTapOccurred = true;
       return nsEventStatus_eConsumeNoDefault;
     }
   }
   return nsEventStatus_eIgnore;
 }
 void AsyncPanZoomController::OnTouchEndOrCancel() {
   if (nsRefPtr<GeckoContentController> controller = GetGeckoContentController()) {
     controller->NotifyAPZStateChange(
         GetGuid(), APZStateChange::EndTouch, mTouchBlockState.mSingleTapOccurred);
   }
 }
 nsEventStatus AsyncPanZoomController::OnSingleTapUp(const TapGestureInput& aEvent) {
   APZC_LOG("%p got a single-tap-up in state %d\n", this, mState);
   // If mZoomConstraints.mAllowDoubleTapZoom is true we wait for a call to OnSingleTapConfirmed before
   // sending event to content
   if (!(mZoomConstraints.mAllowDoubleTapZoom && TouchActionAllowDoubleTapZoom())) {
     return GenerateSingleTap(aEvent.mPoint, aEvent.modifiers);
   }
   return nsEventStatus_eIgnore;
 }
 nsEventStatus AsyncPanZoomController::OnSingleTapConfirmed(const TapGestureInput& aEvent) {
   APZC_LOG("%p got a single-tap-confirmed in state %d\n", this, mState);
   return GenerateSingleTap(aEvent.mPoint, aEvent.modifiers);
 }
 nsEventStatus AsyncPanZoomController::OnDoubleTap(const TapGestureInput& aEvent) {
   APZC_LOG("%p got a double-tap in state %d\n", this, mState);
   nsRefPtr<GeckoContentController> controller = GetGeckoContentController();
   if (controller) {
     if (mZoomConstraints.mAllowDoubleTapZoom && TouchActionAllowDoubleTapZoom()) {
       int32_t modifiers = WidgetModifiersToDOMModifiers(aEvent.modifiers);
       CSSPoint geckoScreenPoint;
       if (ConvertToGecko(aEvent.mPoint, &geckoScreenPoint)) {
         controller->HandleDoubleTap(geckoScreenPoint, modifiers, GetGuid());
       }
     }
     return nsEventStatus_eConsumeNoDefault;
   }
   return nsEventStatus_eIgnore;
 }
 nsEventStatus AsyncPanZoomController::OnCancelTap(const TapGestureInput& aEvent) {
   APZC_LOG("%p got a cancel-tap in state %d\n", this, mState);
   // XXX: Implement this.
   return nsEventStatus_eIgnore;
 }
 float AsyncPanZoomController::PanDistance() {
   ReentrantMonitorAutoEnter lock(mMonitor);
   return NS_hypot(mX.PanDistance(), mY.PanDistance());
 }
 const ScreenPoint AsyncPanZoomController::GetVelocityVector() {
   return ScreenPoint(mX.GetVelocity(), mY.GetVelocity());
 }
 void AsyncPanZoomController::HandlePanningWithTouchAction(double aAngle, TouchBehaviorFlags aBehavior) {
   // Handling of cross sliding will need to be added in this method after touch-action released
   // enabled by default.
   if ((aBehavior & AllowedTouchBehavior::VERTICAL_PAN) && (aBehavior & AllowedTouchBehavior::HORIZONTAL_PAN)) {
     if (mX.Scrollable() && mY.Scrollable()) {
       if (IsCloseToHorizontal(aAngle, AXIS_LOCK_ANGLE)) {
         mY.SetAxisLocked(true);
         SetState(PANNING_LOCKED_X);
       } else if (IsCloseToVertical(aAngle, AXIS_LOCK_ANGLE)) {
         mX.SetAxisLocked(true);
         SetState(PANNING_LOCKED_Y);
       } else {
         SetState(PANNING);
       }
     } else if (mX.Scrollable() || mY.Scrollable()) {
       SetState(PANNING);
     } else {
       SetState(NOTHING);
     }
   } else if (aBehavior & AllowedTouchBehavior::HORIZONTAL_PAN) {
     // Using bigger angle for panning to keep behavior consistent
     // with IE.
     if (IsCloseToHorizontal(aAngle, ALLOWED_DIRECT_PAN_ANGLE)) {
       mY.SetAxisLocked(true);
       SetState(PANNING_LOCKED_X);
       mPanDirRestricted = true;
     } else {
       // Don't treat these touches as pan/zoom movements since 'touch-action' value
       // requires it.
       SetState(NOTHING);
     }
   } else if (aBehavior & AllowedTouchBehavior::VERTICAL_PAN) {
     if (IsCloseToVertical(aAngle, ALLOWED_DIRECT_PAN_ANGLE)) {
       mX.SetAxisLocked(true);
       SetState(PANNING_LOCKED_Y);
       mPanDirRestricted = true;
     } else {
       SetState(NOTHING);
     }
   } else {
     SetState(NOTHING);
   }
 }
 void AsyncPanZoomController::HandlePanning(double aAngle) {
   if (!gfxPrefs::APZCrossSlideEnabled() && (!mX.Scrollable() || !mY.Scrollable())) {
     SetState(PANNING);
   } else if (IsCloseToHorizontal(aAngle, AXIS_LOCK_ANGLE)) {
     mY.SetAxisLocked(true);
     if (mX.Scrollable()) {
       SetState(PANNING_LOCKED_X);
     } else {
       SetState(CROSS_SLIDING_X);
       mX.SetAxisLocked(true);
     }
   } else if (IsCloseToVertical(aAngle, AXIS_LOCK_ANGLE)) {
     mX.SetAxisLocked(true);
     if (mY.Scrollable()) {
       SetState(PANNING_LOCKED_Y);
     } else {
       SetState(CROSS_SLIDING_Y);
       mY.SetAxisLocked(true);
     }
   } else {
     SetState(PANNING);
   }
 }
 nsEventStatus AsyncPanZoomController::StartPanning(const MultiTouchInput& aEvent) {
   ReentrantMonitorAutoEnter lock(mMonitor);
   ScreenIntPoint point = GetFirstTouchScreenPoint(aEvent);
   float dx = mX.PanDistance(point.x);
   float dy = mY.PanDistance(point.y);
   // When the touch move breaks through the pan threshold, reposition the touch down origin
   // so the page won't jump when we start panning.
   mX.StartTouch(point.x);
   mY.StartTouch(point.y);
   mLastEventTime = aEvent.mTime;
   double angle = atan2(dy, dx); // range [-pi, pi]
   angle = fabs(angle); // range [0, pi]
   if (mTouchActionPropertyEnabled) {
     HandlePanningWithTouchAction(angle, GetTouchBehavior(0));
   } else {
     if (GetAxisLockMode() == FREE) {
       SetState(PANNING);
     } else {
       HandlePanning(angle);
     }
   }
   if (IsPanningState(mState)) {
     if (nsRefPtr<GeckoContentController> controller = GetGeckoContentController()) {
       controller->NotifyAPZStateChange(GetGuid(), APZStateChange::StartPanning);
     }
     return nsEventStatus_eConsumeNoDefault;
   }
   // Don't consume an event that didn't trigger a panning.
   return nsEventStatus_eIgnore;
 }
 void AsyncPanZoomController::UpdateWithTouchAtDevicePoint(const MultiTouchInput& aEvent) {
   ScreenIntPoint point = GetFirstTouchScreenPoint(aEvent);
   TimeDuration timeDelta = TimeDuration().FromMilliseconds(aEvent.mTime - mLastEventTime);
   // Probably a duplicate event, just throw it away.
   if (timeDelta.ToMilliseconds() <= EPSILON) {
     return;
   }
   mX.UpdateWithTouchAtDevicePoint(point.x, timeDelta);
   mY.UpdateWithTouchAtDevicePoint(point.y, timeDelta);
 }
 void AsyncPanZoomController::AttemptScroll(const ScreenPoint& aStartPoint,
                                            const ScreenPoint& aEndPoint,
                                            uint32_t aOverscrollHandoffChainIndex) {
   // "start - end" rather than "end - start" because e.g. moving your finger
   // down (*positive* direction along y axis) causes the vertical scroll offset
   // to *decrease* as the page follows your finger.
   ScreenPoint displacement = aStartPoint - aEndPoint;
   ScreenPoint overscroll;  // will be used outside monitor block
   {
     ReentrantMonitorAutoEnter lock(mMonitor);
     CSSToScreenScale zoom = mFrameMetrics.GetZoom();
     // Inversely scale the offset by the resolution (when you're zoomed further in,
     // the same swipe should move you a shorter distance).
     CSSPoint cssDisplacement = displacement / zoom;
     CSSPoint cssOverscroll;
     CSSPoint allowedDisplacement(mX.AdjustDisplacement(cssDisplacement.x,
                                                        cssOverscroll.x),
                                  mY.AdjustDisplacement(cssDisplacement.y,
                                                        cssOverscroll.y));
     overscroll = cssOverscroll * zoom;
     if (!IsZero(allowedDisplacement)) {
       ScrollBy(allowedDisplacement);
       ScheduleComposite();
       TimeDuration timePaintDelta = mPaintThrottler.TimeSinceLastRequest(GetFrameTime());
       if (timePaintDelta.ToMilliseconds() > gfxPrefs::APZPanRepaintInterval()) {
         RequestContentRepaint();
       }
       UpdateSharedCompositorFrameMetrics();
     }
   }
   if (!IsZero(overscroll)) {
     // "+ overscroll" rather than "- overscroll" because "overscroll" is what's
     // left of "displacement", and "displacement" is "start - end".
     CallDispatchScroll(aEndPoint + overscroll, aEndPoint, aOverscrollHandoffChainIndex + 1);
   }
 }
 void AsyncPanZoomController::TakeOverFling(ScreenPoint aVelocity) {
   // We may have a pre-existing velocity for whatever reason (for example,
   // a previously handed off fling). We don't want to clobber that.
   mX.SetVelocity(mX.GetVelocity() + aVelocity.x);
   mY.SetVelocity(mY.GetVelocity() + aVelocity.y);
   SetState(FLING);
   StartAnimation(new FlingAnimation(*this));
 }
 void AsyncPanZoomController::CallDispatchScroll(const ScreenPoint& aStartPoint, const ScreenPoint& aEndPoint,
                                                 uint32_t aOverscrollHandoffChainIndex) {
   // Make a local copy of the tree manager pointer and check if it's not
   // null before calling DispatchScroll(). This is necessary because
   // Destroy(), which nulls out mTreeManager, could be called concurrently.
   APZCTreeManager* treeManagerLocal = mTreeManager;
   if (treeManagerLocal) {
     treeManagerLocal->DispatchScroll(this, aStartPoint, aEndPoint,
                                      aOverscrollHandoffChainIndex);
   }
 }
 void AsyncPanZoomController::TrackTouch(const MultiTouchInput& aEvent) {
   ScreenIntPoint prevTouchPoint(mX.GetPos(), mY.GetPos());
   ScreenIntPoint touchPoint = GetFirstTouchScreenPoint(aEvent);
   TimeDuration timeDelta = TimeDuration().FromMilliseconds(aEvent.mTime - mLastEventTime);
   // Probably a duplicate event, just throw it away.
   if (timeDelta.ToMilliseconds() <= EPSILON) {
     return;
   }
   // If we're axis-locked, check if the user is trying to break the lock
   if (GetAxisLockMode() == STICKY && !mPanDirRestricted) {
     ScreenIntPoint point = GetFirstTouchScreenPoint(aEvent);
     float dx = mX.PanDistance(point.x);
     float dy = mY.PanDistance(point.y);
     double angle = atan2(dy, dx); // range [-pi, pi]
     angle = fabs(angle); // range [0, pi]
     float breakThreshold = AXIS_BREAKOUT_THRESHOLD * APZCTreeManager::GetDPI();
     if (fabs(dx) > breakThreshold || fabs(dy) > breakThreshold) {
       if (mState == PANNING_LOCKED_X || mState == CROSS_SLIDING_X) {
         if (!IsCloseToHorizontal(angle, AXIS_BREAKOUT_ANGLE)) {
           mY.SetAxisLocked(false);
           SetState(PANNING);
         }
       } else if (mState == PANNING_LOCKED_Y || mState == CROSS_SLIDING_Y) {
         if (!IsCloseToVertical(angle, AXIS_BREAKOUT_ANGLE)) {
           mX.SetAxisLocked(false);
           SetState(PANNING);
         }
       }
     }
   }
   UpdateWithTouchAtDevicePoint(aEvent);
   CallDispatchScroll(prevTouchPoint, touchPoint, 0);
 }
 ScreenIntPoint& AsyncPanZoomController::GetFirstTouchScreenPoint(const MultiTouchInput& aEvent) {
   return ((SingleTouchData&)aEvent.mTouches[0]).mScreenPoint;
 }
 bool FlingAnimation::Sample(FrameMetrics& aFrameMetrics,
                             const TimeDuration& aDelta) {
   // If the fling is handed off to our APZC from a child, on the first call to
   // Sample() aDelta might be negative because it's computed as the sample time
   // from SampleContentTransformForFrame() minus our APZC's mLastSampleTime
   // which is the time the child handed off the fling from its call to
   // SampleContentTransformForFrame() with the same sample time. If we allow
   // the negative aDelta to be processed, it will yield a displacement in the
   // direction opposite to the fling, which can cause us to overscroll and
   // hand off the fling to _our_ parent, which effectively kills the fling.
   if (aDelta.ToMilliseconds() <= 0) {
     return true;
   }
   bool shouldContinueFlingX = mApzc.mX.FlingApplyFrictionOrCancel(aDelta),
        shouldContinueFlingY = mApzc.mY.FlingApplyFrictionOrCancel(aDelta);
   // If we shouldn't continue the fling, let's just stop and repaint.
   if (!shouldContinueFlingX && !shouldContinueFlingY) {
     return false;
   }
   // AdjustDisplacement() zeroes out the Axis velocity if we're in overscroll.
   // Since we need to hand off the velocity to the tree manager in such a case,
   // we save it here. Would be ScreenVector instead of ScreenPoint if we had
   // vector classes.
   ScreenPoint velocity(mApzc.mX.GetVelocity(), mApzc.mY.GetVelocity());
   ScreenPoint offset = velocity * aDelta.ToMilliseconds();
   // Inversely scale the offset by the resolution (when you're zoomed further in,
   // the same swipe should move you a shorter distance).
   CSSPoint cssOffset = offset / aFrameMetrics.GetZoom();
   CSSPoint overscroll;
   aFrameMetrics.ScrollBy(CSSPoint(
     mApzc.mX.AdjustDisplacement(cssOffset.x, overscroll.x),
     mApzc.mY.AdjustDisplacement(cssOffset.y, overscroll.y)
   ));
   // If the fling has caused us to reach the end of our scroll range, hand
   // off the fling to the next APZC in the overscroll handoff chain.
   if (!IsZero(overscroll)) {
     // We may have reached the end of the scroll range along one axis but
     // not the other. In such a case we only want to hand off the relevant
     // component of the fling.
     if (FuzzyEqualsMultiplicative(overscroll.x, 0.0f)) {
       velocity.x = 0;
     } else if (FuzzyEqualsMultiplicative(overscroll.y, 0.0f)) {
       velocity.y = 0;
     }
     // To hand off the fling, we call APZCTreeManager::HandleFlingOverscroll()
     // which starts a new fling in the next APZC in the handoff chain with
     // the same velocity. For simplicity, the actual overscroll of the current
     // sample is discarded rather than being handed off. The compositor should
     // sample animations sufficiently frequently that this is not noticeable.
     // Make a local copy of the tree manager pointer and check if it's not
     // null before calling HandleFlingOverscroll(). This is necessary because
     // Destroy(), which nulls out mTreeManager, could be called concurrently.
     APZCTreeManager* treeManagerLocal = mApzc.mTreeManager;
     if (treeManagerLocal) {
       // APZC is holding mMonitor, so directly calling HandleFlingOverscroll()
       // (which acquires the tree lock) would violate the lock ordering. Instead
       // we schedule HandleFlingOverscroll() to be called after mMonitor is
       // released.
       mDeferredTasks.append(NewRunnableMethod(treeManagerLocal,
                                               &APZCTreeManager::HandOffFling,
                                               &mApzc,
                                               velocity));
     }
   }
   return true;
 }
 void AsyncPanZoomController::StartAnimation(AsyncPanZoomAnimation* aAnimation)
 {
   ReentrantMonitorAutoEnter lock(mMonitor);
   mAnimation = aAnimation;
   mLastSampleTime = GetFrameTime();
   ScheduleComposite();
 }
 void AsyncPanZoomController::CancelAnimation() {
   ReentrantMonitorAutoEnter lock(mMonitor);
   SetState(NOTHING);
   mAnimation = nullptr;
 }
 void AsyncPanZoomController::SetCompositorParent(CompositorParent* aCompositorParent) {
   mCompositorParent = aCompositorParent;
 }
 void AsyncPanZoomController::SetCrossProcessCompositorParent(PCompositorParent* aCrossProcessCompositorParent) {
   mCrossProcessCompositorParent = aCrossProcessCompositorParent;
 }
 void AsyncPanZoomController::ScrollBy(const CSSPoint& aOffset) {
   mFrameMetrics.ScrollBy(aOffset);
 }
 void AsyncPanZoomController::ScaleWithFocus(float aScale,
                                             const CSSPoint& aFocus) {
   mFrameMetrics.ZoomBy(aScale);
   // We want to adjust the scroll offset such that the CSS point represented by aFocus remains
   // at the same position on the screen before and after the change in zoom. The below code
   // accomplishes this; see https://bugzilla.mozilla.org/show_bug.cgi?id=923431#c6 for an
   // in-depth explanation of how.
   mFrameMetrics.SetScrollOffset((mFrameMetrics.GetScrollOffset() + aFocus) - (aFocus / aScale));
 }
 /**
  * Enlarges the displayport along both axes based on the velocity.
  */
 static CSSSize
 CalculateDisplayPortSize(const CSSSize& aCompositionSize,
                          const CSSPoint& aVelocity)
 {
   float xMultiplier = fabsf(aVelocity.x) < gfxPrefs::APZMinSkateSpeed()
                         ? gfxPrefs::APZXStationarySizeMultiplier()
                         : gfxPrefs::APZXSkateSizeMultiplier();
   float yMultiplier = fabsf(aVelocity.y) < gfxPrefs::APZMinSkateSpeed()
                         ? gfxPrefs::APZYStationarySizeMultiplier()
                         : gfxPrefs::APZYSkateSizeMultiplier();
   return CSSSize(aCompositionSize.width * xMultiplier,
                  aCompositionSize.height * yMultiplier);
 }
 /**
  * Attempts to redistribute any area in the displayport that would get clipped
  * by the scrollable rect, or be inaccessible due to disabled scrolling, to the
  * other axis, while maintaining total displayport area.
  */
 static void
 RedistributeDisplayPortExcess(CSSSize& aDisplayPortSize,
                               const CSSRect& aScrollableRect)
 {
   float xSlack = std::max(0.0f, aDisplayPortSize.width - aScrollableRect.width);
   float ySlack = std::max(0.0f, aDisplayPortSize.height - aScrollableRect.height);
   if (ySlack > 0) {
     // Reassign wasted y-axis displayport to the x-axis
     aDisplayPortSize.height -= ySlack;
     float xExtra = ySlack * aDisplayPortSize.width / aDisplayPortSize.height;
     aDisplayPortSize.width += xExtra;
   } else if (xSlack > 0) {
     // Reassign wasted x-axis displayport to the y-axis
     aDisplayPortSize.width -= xSlack;
     float yExtra = xSlack * aDisplayPortSize.height / aDisplayPortSize.width;
     aDisplayPortSize.height += yExtra;
   }
 }
 /* static */
 const LayerMargin AsyncPanZoomController::CalculatePendingDisplayPort(
   const FrameMetrics& aFrameMetrics,
   const ScreenPoint& aVelocity,
   double aEstimatedPaintDuration)
 {
   CSSSize compositionBounds = aFrameMetrics.CalculateCompositedSizeInCssPixels();
   CSSSize compositionSize = aFrameMetrics.GetRootCompositionSize();
   compositionSize =
     CSSSize(std::min(compositionBounds.width, compositionSize.width),
             std::min(compositionBounds.height, compositionSize.height));
   CSSPoint velocity = aVelocity / aFrameMetrics.GetZoom();
   CSSPoint scrollOffset = aFrameMetrics.GetScrollOffset();
   CSSRect scrollableRect = aFrameMetrics.GetExpandedScrollableRect();
   // Calculate the displayport size based on how fast we're moving along each axis.
   CSSSize displayPortSize = CalculateDisplayPortSize(compositionSize, velocity);
   if (gfxPrefs::APZEnlargeDisplayPortWhenClipped()) {
     RedistributeDisplayPortExcess(displayPortSize, scrollableRect);
   }
   // Offset the displayport, depending on how fast we're moving and the
   // estimated time it takes to paint, to try to minimise checkerboarding.
   float estimatedPaintDurationMillis = (float)(aEstimatedPaintDuration * 1000.0);
   float paintFactor = (gfxPrefs::APZUsePaintDuration() ? estimatedPaintDurationMillis : 50.0f);
   CSSRect displayPort = CSSRect(scrollOffset + (velocity * paintFactor * gfxPrefs::APZVelocityBias()),
                                 displayPortSize);
   // Re-center the displayport based on its expansion over the composition size.
   displayPort.MoveBy((compositionSize.width - displayPort.width)/2.0f,
                      (compositionSize.height - displayPort.height)/2.0f);
   // Make sure the displayport remains within the scrollable rect.
   displayPort = displayPort.ForceInside(scrollableRect) - scrollOffset;
   APZC_LOG_FM(aFrameMetrics,
     "Calculated displayport as (%f %f %f %f) from velocity (%f %f) paint time %f metrics",
     displayPort.x, displayPort.y, displayPort.width, displayPort.height,
     aVelocity.x, aVelocity.y, (float)estimatedPaintDurationMillis);
   CSSMargin cssMargins;
   cssMargins.left = -displayPort.x;
   cssMargins.top = -displayPort.y;
   cssMargins.right = displayPort.width - compositionSize.width - cssMargins.left;
   cssMargins.bottom = displayPort.height - compositionSize.height - cssMargins.top;
   LayerMargin layerMargins = cssMargins * aFrameMetrics.LayersPixelsPerCSSPixel();
   return layerMargins;
 }
 void AsyncPanZoomController::ScheduleComposite() {
   if (mCompositorParent) {
     mCompositorParent->ScheduleRenderOnCompositorThread();
   }
 }
 void AsyncPanZoomController::FlushRepaintForOverscrollHandoff() {
   ReentrantMonitorAutoEnter lock(mMonitor);
   RequestContentRepaint();
   UpdateSharedCompositorFrameMetrics();
 }
 bool AsyncPanZoomController::IsPannable() const {
   ReentrantMonitorAutoEnter lock(mMonitor);
   return mX.HasRoomToPan() || mY.HasRoomToPan();
 }
 void AsyncPanZoomController::RequestContentRepaint() {
   RequestContentRepaint(mFrameMetrics);
 }
 void AsyncPanZoomController::RequestContentRepaint(FrameMetrics& aFrameMetrics) {
   aFrameMetrics.SetDisplayPortMargins(
     CalculatePendingDisplayPort(aFrameMetrics,
                                 GetVelocityVector(),
                                 mPaintThrottler.AverageDuration().ToSeconds()));
   aFrameMetrics.SetUseDisplayPortMargins();
   // If we're trying to paint what we already think is painted, discard this
   // request since it's a pointless paint.
   LayerMargin marginDelta = mLastPaintRequestMetrics.GetDisplayPortMargins()
                           - aFrameMetrics.GetDisplayPortMargins();
   if (fabsf(marginDelta.left) < EPSILON &&
       fabsf(marginDelta.top) < EPSILON &&
       fabsf(marginDelta.right) < EPSILON &&
       fabsf(marginDelta.bottom) < EPSILON &&
       fabsf(mLastPaintRequestMetrics.GetScrollOffset().x -
             aFrameMetrics.GetScrollOffset().x) < EPSILON &&
       fabsf(mLastPaintRequestMetrics.GetScrollOffset().y -
             aFrameMetrics.GetScrollOffset().y) < EPSILON &&
       aFrameMetrics.GetZoom() == mLastPaintRequestMetrics.GetZoom() &&
       fabsf(aFrameMetrics.mViewport.width - mLastPaintRequestMetrics.mViewport.width) < EPSILON &&
       fabsf(aFrameMetrics.mViewport.height - mLastPaintRequestMetrics.mViewport.height) < EPSILON) {
     return;
   }
   SendAsyncScrollEvent();
   mPaintThrottler.PostTask(
     FROM_HERE,
     NewRunnableMethod(this,
                       &AsyncPanZoomController::DispatchRepaintRequest,
                       aFrameMetrics),
     GetFrameTime());
   aFrameMetrics.mPresShellId = mLastContentPaintMetrics.mPresShellId;
   mLastPaintRequestMetrics = aFrameMetrics;
 }
 /*static*/ CSSRect
 GetDisplayPortRect(const FrameMetrics& aFrameMetrics)
 {
   // This computation is based on what happens in CalculatePendingDisplayPort. If that
   // changes then this might need to change too
   CSSRect baseRect(aFrameMetrics.GetScrollOffset(),
                    CSSSize(std::min(aFrameMetrics.CalculateCompositedSizeInCssPixels().width,
                                     aFrameMetrics.GetRootCompositionSize().width),
                            std::min(aFrameMetrics.CalculateCompositedSizeInCssPixels().height,
                                     aFrameMetrics.GetRootCompositionSize().height)));
   baseRect.Inflate(aFrameMetrics.GetDisplayPortMargins() / aFrameMetrics.LayersPixelsPerCSSPixel());
   return baseRect;
 }
 void
 AsyncPanZoomController::DispatchRepaintRequest(const FrameMetrics& aFrameMetrics) {
   nsRefPtr<GeckoContentController> controller = GetGeckoContentController();
   if (controller) {
     APZC_LOG_FM(aFrameMetrics, "%p requesting content repaint", this);
     LogRendertraceRect(GetGuid(), "requested displayport", "yellow", GetDisplayPortRect(aFrameMetrics));
     controller->RequestContentRepaint(aFrameMetrics);
     mLastDispatchedPaintMetrics = aFrameMetrics;
   }
 }
 void
 AsyncPanZoomController::FireAsyncScrollOnTimeout()
 {
   if (mCurrentAsyncScrollOffset != mLastAsyncScrollOffset) {
     ReentrantMonitorAutoEnter lock(mMonitor);
     SendAsyncScrollEvent();
   }
   mAsyncScrollTimeoutTask = nullptr;
 }
 bool ZoomAnimation::Sample(FrameMetrics& aFrameMetrics,
                            const TimeDuration& aDelta) {
   mDuration += aDelta;
   double animPosition = mDuration / ZOOM_TO_DURATION;
   if (animPosition >= 1.0) {
     aFrameMetrics.SetZoom(mEndZoom);
     aFrameMetrics.SetScrollOffset(mEndOffset);
     return false;
   }
   // Sample the zoom at the current time point.  The sampled zoom
   // will affect the final computed resolution.
   double sampledPosition = gComputedTimingFunction->GetValue(animPosition);
   // We scale the scrollOffset linearly with sampledPosition, so the zoom
   // needs to scale inversely to match.
   aFrameMetrics.SetZoom(CSSToScreenScale(1 /
     (sampledPosition / mEndZoom.scale +
     (1 - sampledPosition) / mStartZoom.scale)));
   aFrameMetrics.SetScrollOffset(CSSPoint::FromUnknownPoint(gfx::Point(
     mEndOffset.x * sampledPosition + mStartOffset.x * (1 - sampledPosition),
     mEndOffset.y * sampledPosition + mStartOffset.y * (1 - sampledPosition)
   )));
   return true;
 }
 bool AsyncPanZoomController::UpdateAnimation(const TimeStamp& aSampleTime)
 {
   if (mAnimation) {
     if (mAnimation->Sample(mFrameMetrics, aSampleTime - mLastSampleTime)) {
       if (mPaintThrottler.TimeSinceLastRequest(aSampleTime) >
           mAnimation->mRepaintInterval) {
         RequestContentRepaint();
       }
     } else {
       mAnimation = nullptr;
       SetState(NOTHING);
       SendAsyncScrollEvent();
       RequestContentRepaint();
     }
     UpdateSharedCompositorFrameMetrics();
     mLastSampleTime = aSampleTime;
     return true;
   }
   return false;
 }
 bool AsyncPanZoomController::SampleContentTransformForFrame(const TimeStamp& aSampleTime,
                                                             ViewTransform* aNewTransform,
                                                             ScreenPoint& aScrollOffset) {
   // The eventual return value of this function. The compositor needs to know
   // whether or not to advance by a frame as soon as it can. For example, if a
   // fling is happening, it has to keep compositing so that the animation is
   // smooth. If an animation frame is requested, it is the compositor's
   // responsibility to schedule a composite.
   bool requestAnimationFrame = false;
   Vector<Task*> deferredTasks;
   {
     ReentrantMonitorAutoEnter lock(mMonitor);
     requestAnimationFrame = UpdateAnimation(aSampleTime);
     aScrollOffset = mFrameMetrics.GetScrollOffset() * mFrameMetrics.GetZoom();
     *aNewTransform = GetCurrentAsyncTransform();
     LogRendertraceRect(GetGuid(), "viewport", "red",
       CSSRect(mFrameMetrics.GetScrollOffset(),
               ParentLayerSize(mFrameMetrics.mCompositionBounds.Size()) / mFrameMetrics.GetZoomToParent()));
     mCurrentAsyncScrollOffset = mFrameMetrics.GetScrollOffset();
     // Get any deferred tasks queued up by mAnimation's Sample() (called by
     // UpdateAnimation()). This needs to be done here since mAnimation can
     // be destroyed by another thread when we release the monitor, but
     // the tasks need to be executed after we release the monitor since they
     // are allowed to call APZCTreeManager methods which can grab the tree lock.
     if (mAnimation) {
       deferredTasks = mAnimation->TakeDeferredTasks();
     }
   }
   for (uint32_t i = 0; i < deferredTasks.length(); ++i) {
     deferredTasks[i]->Run();
     delete deferredTasks[i];
   }
   // Cancel the mAsyncScrollTimeoutTask because we will fire a
   // mozbrowserasyncscroll event or renew the mAsyncScrollTimeoutTask again.
   if (mAsyncScrollTimeoutTask) {
     mAsyncScrollTimeoutTask->Cancel();
     mAsyncScrollTimeoutTask = nullptr;
   }
   // Fire the mozbrowserasyncscroll event immediately if it's been
   // sAsyncScrollThrottleTime ms since the last time we fired the event and the
   // current scroll offset is different than the mLastAsyncScrollOffset we sent
   // with the last event.
   // Otherwise, start a timer to fire the event sAsyncScrollTimeout ms from now.
   TimeDuration delta = aSampleTime - mLastAsyncScrollTime;
   if (delta.ToMilliseconds() > gfxPrefs::APZAsyncScrollThrottleTime() &&
       mCurrentAsyncScrollOffset != mLastAsyncScrollOffset) {
     ReentrantMonitorAutoEnter lock(mMonitor);
     mLastAsyncScrollTime = aSampleTime;
     mLastAsyncScrollOffset = mCurrentAsyncScrollOffset;
     SendAsyncScrollEvent();
   }
   else {
     mAsyncScrollTimeoutTask =
       NewRunnableMethod(this, &AsyncPanZoomController::FireAsyncScrollOnTimeout);
     MessageLoop::current()->PostDelayedTask(FROM_HERE,
                                             mAsyncScrollTimeoutTask,
                                             gfxPrefs::APZAsyncScrollTimeout());
   }
   return requestAnimationFrame;
 }
 ViewTransform AsyncPanZoomController::GetCurrentAsyncTransform() {
   ReentrantMonitorAutoEnter lock(mMonitor);
   CSSPoint lastPaintScrollOffset;
   if (mLastContentPaintMetrics.IsScrollable()) {
     lastPaintScrollOffset = mLastContentPaintMetrics.GetScrollOffset();
   }
   CSSPoint currentScrollOffset = mFrameMetrics.GetScrollOffset() +
     mTestAsyncScrollOffset;
   // If checkerboarding has been disallowed, clamp the scroll position to stay
   // within rendered content.
   if (!gfxPrefs::APZAllowCheckerboarding() &&
       !mLastContentPaintMetrics.mDisplayPort.IsEmpty()) {
     CSSSize compositedSize = mLastContentPaintMetrics.CalculateCompositedSizeInCssPixels();
     CSSPoint maxScrollOffset = lastPaintScrollOffset +
       CSSPoint(mLastContentPaintMetrics.mDisplayPort.XMost() - compositedSize.width,
                mLastContentPaintMetrics.mDisplayPort.YMost() - compositedSize.height);
     CSSPoint minScrollOffset = lastPaintScrollOffset + mLastContentPaintMetrics.mDisplayPort.TopLeft();
     if (minScrollOffset.x < maxScrollOffset.x) {
       currentScrollOffset.x = clamped(currentScrollOffset.x, minScrollOffset.x, maxScrollOffset.x);
     }
     if (minScrollOffset.y < maxScrollOffset.y) {
       currentScrollOffset.y = clamped(currentScrollOffset.y, minScrollOffset.y, maxScrollOffset.y);
     }
   }
   LayerPoint translation = (currentScrollOffset - lastPaintScrollOffset)
                          * mLastContentPaintMetrics.LayersPixelsPerCSSPixel();
   return ViewTransform(-translation,
                        mFrameMetrics.GetZoom()
                      / mLastContentPaintMetrics.mDevPixelsPerCSSPixel
                      / mFrameMetrics.GetParentResolution());
 }
 gfx3DMatrix AsyncPanZoomController::GetNontransientAsyncTransform() {
   ReentrantMonitorAutoEnter lock(mMonitor);
   return gfx3DMatrix::ScalingMatrix(mLastContentPaintMetrics.mResolution.scale,
                                     mLastContentPaintMetrics.mResolution.scale,
 .0f);
 }
 gfx3DMatrix AsyncPanZoomController::GetTransformToLastDispatchedPaint() {
   ReentrantMonitorAutoEnter lock(mMonitor);
   LayerPoint scrollChange = (mLastContentPaintMetrics.GetScrollOffset() - mLastDispatchedPaintMetrics.GetScrollOffset())
                           * mLastContentPaintMetrics.LayersPixelsPerCSSPixel();
   float zoomChange = mLastContentPaintMetrics.GetZoom().scale / mLastDispatchedPaintMetrics.GetZoom().scale;
   return gfx3DMatrix::Translation(scrollChange.x, scrollChange.y, 0) *
          gfx3DMatrix::ScalingMatrix(zoomChange, zoomChange, 1);
 }
 void AsyncPanZoomController::NotifyLayersUpdated(const FrameMetrics& aLayerMetrics, bool aIsFirstPaint) {
   ReentrantMonitorAutoEnter lock(mMonitor);
   mLastContentPaintMetrics = aLayerMetrics;
   UpdateTransformScale();
   bool isDefault = mFrameMetrics.IsDefault();
   mFrameMetrics.mMayHaveTouchListeners = aLayerMetrics.mMayHaveTouchListeners;
   APZC_LOG_FM(aLayerMetrics, "%p got a NotifyLayersUpdated with aIsFirstPaint=%d", this, aIsFirstPaint);
   LogRendertraceRect(GetGuid(), "page", "brown", aLayerMetrics.mScrollableRect);
   LogRendertraceRect(GetGuid(), "painted displayport", "green",
     aLayerMetrics.mDisplayPort + aLayerMetrics.GetScrollOffset());
   mPaintThrottler.TaskComplete(GetFrameTime());
   bool needContentRepaint = false;
   if (aLayerMetrics.mCompositionBounds.width == mFrameMetrics.mCompositionBounds.width &&
       aLayerMetrics.mCompositionBounds.height == mFrameMetrics.mCompositionBounds.height) {
     // Remote content has sync'd up to the composition geometry
     // change, so we can accept the viewport it's calculated.
     if (mFrameMetrics.mViewport.width != aLayerMetrics.mViewport.width ||
         mFrameMetrics.mViewport.height != aLayerMetrics.mViewport.height) {
       needContentRepaint = true;
     }
     mFrameMetrics.mViewport = aLayerMetrics.mViewport;
   }
   // If the layers update was not triggered by our own repaint request, then
   // we want to take the new scroll offset. Check the scroll generation as well
   // to filter duplicate calls to NotifyLayersUpdated with the same scroll offset
   // update message.
   bool scrollOffsetUpdated = aLayerMetrics.GetScrollOffsetUpdated()
         && (aLayerMetrics.GetScrollGeneration() != mFrameMetrics.GetScrollGeneration());
   if (aIsFirstPaint || isDefault) {
     // Initialize our internal state to something sane when the content
     // that was just painted is something we knew nothing about previously
     mPaintThrottler.ClearHistory();
     mPaintThrottler.SetMaxDurations(gfxPrefs::APZNumPaintDurationSamples());
     mX.CancelTouch();
     mY.CancelTouch();
     SetState(NOTHING);
     mFrameMetrics = aLayerMetrics;
     mLastDispatchedPaintMetrics = aLayerMetrics;
     ShareCompositorFrameMetrics();
   } else {
     // If we're not taking the aLayerMetrics wholesale we still need to pull
     // in some things into our local mFrameMetrics because these things are
     // determined by Gecko and our copy in mFrameMetrics may be stale.
     if (mFrameMetrics.mCompositionBounds.width == aLayerMetrics.mCompositionBounds.width &&
         mFrameMetrics.mDevPixelsPerCSSPixel == aLayerMetrics.mDevPixelsPerCSSPixel) {
       float parentResolutionChange = aLayerMetrics.GetParentResolution().scale
                                    / mFrameMetrics.GetParentResolution().scale;
       mFrameMetrics.ZoomBy(parentResolutionChange);
     } else {
       // Take the new zoom as either device scale or composition width or both
       // got changed (e.g. due to orientation change).
       mFrameMetrics.SetZoom(aLayerMetrics.GetZoom());
       mFrameMetrics.mDevPixelsPerCSSPixel.scale = aLayerMetrics.mDevPixelsPerCSSPixel.scale;
     }
     mFrameMetrics.mScrollableRect = aLayerMetrics.mScrollableRect;
     mFrameMetrics.mCompositionBounds = aLayerMetrics.mCompositionBounds;
     mFrameMetrics.SetRootCompositionSize(aLayerMetrics.GetRootCompositionSize());
     mFrameMetrics.mResolution = aLayerMetrics.mResolution;
     mFrameMetrics.mCumulativeResolution = aLayerMetrics.mCumulativeResolution;
     mFrameMetrics.mHasScrollgrab = aLayerMetrics.mHasScrollgrab;
     if (scrollOffsetUpdated) {
       APZC_LOG("%p updating scroll offset from (%f, %f) to (%f, %f)\n", this,
         mFrameMetrics.GetScrollOffset().x, mFrameMetrics.GetScrollOffset().y,
         aLayerMetrics.GetScrollOffset().x, aLayerMetrics.GetScrollOffset().y);
       mFrameMetrics.CopyScrollInfoFrom(aLayerMetrics);
       // Because of the scroll offset update, any inflight paint requests are
       // going to be ignored by layout, and so mLastDispatchedPaintMetrics
       // becomes incorrect for the purposes of calculating the LD transform. To
       // correct this we need to update mLastDispatchedPaintMetrics to be the
       // last thing we know was painted by Gecko.
       mLastDispatchedPaintMetrics = aLayerMetrics;
     }
   }
   if (scrollOffsetUpdated) {
     // Once layout issues a scroll offset update, it becomes impervious to
     // scroll offset updates from APZ until we acknowledge the update it sent.
     // This prevents APZ updates from clobbering scroll updates from other
     // more "legitimate" sources like content scripts.
     nsRefPtr<GeckoContentController> controller = GetGeckoContentController();
     if (controller) {
       APZC_LOG("%p sending scroll update acknowledgement with gen %lu\n", this, aLayerMetrics.GetScrollGeneration());
       controller->AcknowledgeScrollUpdate(aLayerMetrics.GetScrollId(),
                                           aLayerMetrics.GetScrollGeneration());
     }
   }
   if (needContentRepaint) {
     RequestContentRepaint();
   }
   UpdateSharedCompositorFrameMetrics();
 }
 const FrameMetrics& AsyncPanZoomController::GetFrameMetrics() {
   mMonitor.AssertCurrentThreadIn();
   return mFrameMetrics;
 }
 void AsyncPanZoomController::ZoomToRect(CSSRect aRect) {
   if (!aRect.IsFinite()) {
     NS_WARNING("ZoomToRect got called with a non-finite rect; ignoring...\n");
     return;
   }
   SetState(ANIMATING_ZOOM);
   {
     ReentrantMonitorAutoEnter lock(mMonitor);
     ParentLayerIntRect compositionBounds = mFrameMetrics.mCompositionBounds;
     CSSRect cssPageRect = mFrameMetrics.mScrollableRect;
     CSSPoint scrollOffset = mFrameMetrics.GetScrollOffset();
     CSSToParentLayerScale currentZoom = mFrameMetrics.GetZoomToParent();
     CSSToParentLayerScale targetZoom;
     // The minimum zoom to prevent over-zoom-out.
     // If the zoom factor is lower than this (i.e. we are zoomed more into the page),
     // then the CSS content rect, in layers pixels, will be smaller than the
     // composition bounds. If this happens, we can't fill the target composited
     // area with this frame.
     CSSToParentLayerScale localMinZoom(std::max((mZoomConstraints.mMinZoom * mFrameMetrics.mTransformScale).scale,
                                        std::max(compositionBounds.width / cssPageRect.width,
                                                 compositionBounds.height / cssPageRect.height)));
     CSSToParentLayerScale localMaxZoom = mZoomConstraints.mMaxZoom * mFrameMetrics.mTransformScale;
     if (!aRect.IsEmpty()) {
       // Intersect the zoom-to-rect to the CSS rect to make sure it fits.
       aRect = aRect.Intersect(cssPageRect);
       targetZoom = CSSToParentLayerScale(std::min(compositionBounds.width / aRect.width,
                                                   compositionBounds.height / aRect.height));
     }
     // 1. If the rect is empty, request received from browserElementScrolling.js
     // 2. currentZoom is equal to mZoomConstraints.mMaxZoom and user still double-tapping it
     // 3. currentZoom is equal to localMinZoom and user still double-tapping it
     // Treat these three cases as a request to zoom out as much as possible.
     if (aRect.IsEmpty() ||
         (currentZoom == localMaxZoom && targetZoom >= localMaxZoom) ||
         (currentZoom == localMinZoom && targetZoom <= localMinZoom)) {
       CSSSize compositedSize = mFrameMetrics.CalculateCompositedSizeInCssPixels();
       float y = scrollOffset.y;
       float newHeight =
         cssPageRect.width * (compositedSize.height / compositedSize.width);
       float dh = compositedSize.height - newHeight;
       aRect = CSSRect(0.0f,
                       y + dh/2,
                       cssPageRect.width,
                       newHeight);
       aRect = aRect.Intersect(cssPageRect);
       targetZoom = CSSToParentLayerScale(std::min(compositionBounds.width / aRect.width,
                                                   compositionBounds.height / aRect.height));
     }
     targetZoom.scale = clamped(targetZoom.scale, localMinZoom.scale, localMaxZoom.scale);
     FrameMetrics endZoomToMetrics = mFrameMetrics;
     endZoomToMetrics.SetZoom(targetZoom / mFrameMetrics.mTransformScale);
     // Adjust the zoomToRect to a sensible position to prevent overscrolling.
     CSSSize sizeAfterZoom = endZoomToMetrics.CalculateCompositedSizeInCssPixels();
     // If either of these conditions are met, the page will be
     // overscrolled after zoomed
     if (aRect.y + sizeAfterZoom.height > cssPageRect.height) {
       aRect.y = cssPageRect.height - sizeAfterZoom.height;
       aRect.y = aRect.y > 0 ? aRect.y : 0;
     }
     if (aRect.x + sizeAfterZoom.width > cssPageRect.width) {
       aRect.x = cssPageRect.width - sizeAfterZoom.width;
       aRect.x = aRect.x > 0 ? aRect.x : 0;
     }
     endZoomToMetrics.SetScrollOffset(aRect.TopLeft());
     endZoomToMetrics.SetDisplayPortMargins(
       CalculatePendingDisplayPort(endZoomToMetrics,
                                   ScreenPoint(0,0),
 ));
     endZoomToMetrics.SetUseDisplayPortMargins();
     StartAnimation(new ZoomAnimation(
         mFrameMetrics.GetScrollOffset(),
         mFrameMetrics.GetZoom(),
         endZoomToMetrics.GetScrollOffset(),
         endZoomToMetrics.GetZoom()));
     // Schedule a repaint now, so the new displayport will be painted before the
     // animation finishes.
     RequestContentRepaint(endZoomToMetrics);
   }
 }
 void AsyncPanZoomController::ContentReceivedTouch(bool aPreventDefault) {
   mTouchBlockState.mPreventDefaultSet = true;
   mTouchBlockState.mPreventDefault = aPreventDefault;
   CheckContentResponse();
 }
 void AsyncPanZoomController::CheckContentResponse() {
   bool canProceedToTouchState = true;
   if (mFrameMetrics.mMayHaveTouchListeners) {
     canProceedToTouchState &= mTouchBlockState.mPreventDefaultSet;
   }
   if (mTouchActionPropertyEnabled) {
     canProceedToTouchState &= mTouchBlockState.mAllowedTouchBehaviorSet;
   }
   if (!canProceedToTouchState) {
     return;
   }
   if (mContentResponseTimeoutTask) {
     mContentResponseTimeoutTask->Cancel();
     mContentResponseTimeoutTask = nullptr;
   }
   if (mState == WAITING_CONTENT_RESPONSE) {
     if (!mTouchBlockState.mPreventDefault) {
       SetState(NOTHING);
     }
     mHandlingTouchQueue = true;
     while (!mTouchQueue.IsEmpty()) {
       if (!mTouchBlockState.mPreventDefault) {
         HandleInputEvent(mTouchQueue[0]);
       }
       if (mTouchQueue[0].mType == MultiTouchInput::MULTITOUCH_END ||
           mTouchQueue[0].mType == MultiTouchInput::MULTITOUCH_CANCEL) {
         mTouchQueue.RemoveElementAt(0);
         break;
       }
       mTouchQueue.RemoveElementAt(0);
     }
     mHandlingTouchQueue = false;
   }
 }
 bool AsyncPanZoomController::TouchActionAllowPinchZoom() {
   if (!mTouchActionPropertyEnabled) {
     return true;
   }
   // Pointer events specification implies all touch points to allow zoom
   // to perform it.
   for (size_t i = 0; i < mTouchBlockState.mAllowedTouchBehaviors.Length(); i++) {
     if (!(mTouchBlockState.mAllowedTouchBehaviors[i] & AllowedTouchBehavior::PINCH_ZOOM)) {
       return false;
     }
   }
   return true;
 }
 bool AsyncPanZoomController::TouchActionAllowDoubleTapZoom() {
   if (!mTouchActionPropertyEnabled) {
     return true;
   }
   for (size_t i = 0; i < mTouchBlockState.mAllowedTouchBehaviors.Length(); i++) {
     if (!(mTouchBlockState.mAllowedTouchBehaviors[i] & AllowedTouchBehavior::DOUBLE_TAP_ZOOM)) {
       return false;
     }
   }
   return true;
 }
 AsyncPanZoomController::TouchBehaviorFlags
 AsyncPanZoomController::GetTouchBehavior(uint32_t touchIndex) {
   if (touchIndex < mTouchBlockState.mAllowedTouchBehaviors.Length()) {
     return mTouchBlockState.mAllowedTouchBehaviors[touchIndex];
   }
   return DefaultTouchBehavior;
 }
 AsyncPanZoomController::TouchBehaviorFlags
 AsyncPanZoomController::GetAllowedTouchBehavior(ScreenIntPoint& aPoint) {
   // Here we need to perform a hit testing over the touch-action regions attached to the
   // layer associated with current apzc.
   // Currently they are in progress, for more info see bug 928833.
   return AllowedTouchBehavior::UNKNOWN;
 }
 void AsyncPanZoomController::SetAllowedTouchBehavior(const nsTArray<TouchBehaviorFlags>& aBehaviors) {
   mTouchBlockState.mAllowedTouchBehaviors.Clear();
   mTouchBlockState.mAllowedTouchBehaviors.AppendElements(aBehaviors);
   mTouchBlockState.mAllowedTouchBehaviorSet = true;
   CheckContentResponse();
 }
 void AsyncPanZoomController::SetState(PanZoomState aNewState) {
   PanZoomState oldState;
   // Intentional scoping for mutex
   {
     ReentrantMonitorAutoEnter lock(mMonitor);
     oldState = mState;
     mState = aNewState;
   }
   if (nsRefPtr<GeckoContentController> controller = GetGeckoContentController()) {
     if (!IsTransformingState(oldState) && IsTransformingState(aNewState)) {
       controller->NotifyAPZStateChange(
           GetGuid(), APZStateChange::TransformBegin);
     } else if (IsTransformingState(oldState) && !IsTransformingState(aNewState)) {
       controller->NotifyAPZStateChange(
           GetGuid(), APZStateChange::TransformEnd);
     }
   }
 }
 bool AsyncPanZoomController::IsTransformingState(PanZoomState aState) {
   return !(aState == NOTHING || aState == TOUCHING || aState == WAITING_CONTENT_RESPONSE);
 }
 bool AsyncPanZoomController::IsPanningState(PanZoomState aState) {
   return (aState == PANNING || aState == PANNING_LOCKED_X || aState == PANNING_LOCKED_Y);
 }
 void AsyncPanZoomController::SetContentResponseTimer() {
   if (!mContentResponseTimeoutTask) {
     mContentResponseTimeoutTask =
       NewRunnableMethod(this, &AsyncPanZoomController::TimeoutContentResponse);
     PostDelayedTask(mContentResponseTimeoutTask, gfxPrefs::APZContentResponseTimeout());
   }
 }
 void AsyncPanZoomController::TimeoutContentResponse() {
   mContentResponseTimeoutTask = nullptr;
   ContentReceivedTouch(false);
 }
 void AsyncPanZoomController::UpdateZoomConstraints(const ZoomConstraints& aConstraints) {
   APZC_LOG("%p updating zoom constraints to %d %d %f %f\n", this, aConstraints.mAllowZoom,
     aConstraints.mAllowDoubleTapZoom, aConstraints.mMinZoom.scale, aConstraints.mMaxZoom.scale);
   if (IsNaN(aConstraints.mMinZoom.scale) || IsNaN(aConstraints.mMaxZoom.scale)) {
     NS_WARNING("APZC received zoom constraints with NaN values; dropping...\n");
     return;
   }
   // inf float values and other bad cases should be sanitized by the code below.
   mZoomConstraints.mAllowZoom = aConstraints.mAllowZoom;
   mZoomConstraints.mAllowDoubleTapZoom = aConstraints.mAllowDoubleTapZoom;
   mZoomConstraints.mMinZoom = (MIN_ZOOM > aConstraints.mMinZoom ? MIN_ZOOM : aConstraints.mMinZoom);
   mZoomConstraints.mMaxZoom = (MAX_ZOOM > aConstraints.mMaxZoom ? aConstraints.mMaxZoom : MAX_ZOOM);
   if (mZoomConstraints.mMaxZoom < mZoomConstraints.mMinZoom) {
     mZoomConstraints.mMaxZoom = mZoomConstraints.mMinZoom;
   }
 }
 ZoomConstraints
 AsyncPanZoomController::GetZoomConstraints() const
 {
   return mZoomConstraints;
 }
 void AsyncPanZoomController::PostDelayedTask(Task* aTask, int aDelayMs) {
   nsRefPtr<GeckoContentController> controller = GetGeckoContentController();
   if (controller) {
     controller->PostDelayedTask(aTask, aDelayMs);
   }
 }
 void AsyncPanZoomController::SendAsyncScrollEvent() {
   nsRefPtr<GeckoContentController> controller = GetGeckoContentController();
   if (!controller) {
     return;
   }
   bool isRoot;
   CSSRect contentRect;
   CSSSize scrollableSize;
   {
     ReentrantMonitorAutoEnter lock(mMonitor);
     isRoot = mFrameMetrics.mIsRoot;
     scrollableSize = mFrameMetrics.mScrollableRect.Size();
     contentRect = mFrameMetrics.CalculateCompositedRectInCssPixels();
     contentRect.MoveTo(mCurrentAsyncScrollOffset);
   }
   controller->SendAsyncScrollDOMEvent(isRoot, contentRect, scrollableSize);
 }
 bool AsyncPanZoomController::Matches(const ScrollableLayerGuid& aGuid)
 {
   return aGuid == GetGuid();
 }
 void AsyncPanZoomController::GetGuid(ScrollableLayerGuid* aGuidOut)
 {
   if (aGuidOut) {
     *aGuidOut = GetGuid();
   }
 }
 ScrollableLayerGuid AsyncPanZoomController::GetGuid()
 {
   return ScrollableLayerGuid(mLayersId, mFrameMetrics);
 }
 void AsyncPanZoomController::UpdateSharedCompositorFrameMetrics()
 {
   mMonitor.AssertCurrentThreadIn();
   FrameMetrics* frame = mSharedFrameMetricsBuffer ?
       static_cast<FrameMetrics*>(mSharedFrameMetricsBuffer->memory()) : nullptr;
   if (frame && mSharedLock && gfxPrefs::UseProgressiveTilePainting()) {
     mSharedLock->Lock();
     *frame = mFrameMetrics;
     mSharedLock->Unlock();
   }
 }
 void AsyncPanZoomController::ShareCompositorFrameMetrics() {
   PCompositorParent* compositor =
     (mCrossProcessCompositorParent ? mCrossProcessCompositorParent : mCompositorParent.get());
   // Only create the shared memory buffer if it hasn't already been created,
   // we are using progressive tile painting, and we have a
   // compositor to pass the shared memory back to the content process/thread.
   if (!mSharedFrameMetricsBuffer && compositor && gfxPrefs::UseProgressiveTilePainting()) {
     // Create shared memory and initialize it with the current FrameMetrics value
     mSharedFrameMetricsBuffer = new ipc::SharedMemoryBasic;
     FrameMetrics* frame = nullptr;
     mSharedFrameMetricsBuffer->Create(sizeof(FrameMetrics));
     mSharedFrameMetricsBuffer->Map(sizeof(FrameMetrics));
     frame = static_cast<FrameMetrics*>(mSharedFrameMetricsBuffer->memory());
     if (frame) {
       { // scope the monitor, only needed to copy the FrameMetrics.
         ReentrantMonitorAutoEnter lock(mMonitor);
         *frame = mFrameMetrics;
       }
       // Get the process id of the content process
       base::ProcessHandle processHandle = compositor->OtherProcess();
       ipc::SharedMemoryBasic::Handle mem = ipc::SharedMemoryBasic::NULLHandle();
       // Get the shared memory handle to share with the content process
       mSharedFrameMetricsBuffer->ShareToProcess(processHandle, &mem);
       // Get the cross process mutex handle to share with the content process
       mSharedLock = new CrossProcessMutex("AsyncPanZoomControlLock");
       CrossProcessMutexHandle handle = mSharedLock->ShareToProcess(processHandle);
       // Send the shared memory handle and cross process handle to the content
       // process by an asynchronous ipc call. Include the APZC unique ID
       // so the content process know which APZC sent this shared FrameMetrics.
       if (!compositor->SendSharedCompositorFrameMetrics(mem, handle, mAPZCId)) {
         APZC_LOG("%p failed to share FrameMetrics with content process.", this);
       }
     }
   }
 }
 ParentLayerPoint AsyncPanZoomController::ToParentLayerCoords(const ScreenPoint& aPoint)
 {
   return TransformTo<ParentLayerPixel>(GetNontransientAsyncTransform() * GetCSSTransform(), aPoint);
 }
 void AsyncPanZoomController::UpdateTransformScale()
 {
   gfx3DMatrix nontransientTransforms = GetNontransientAsyncTransform() * GetCSSTransform();
   if (!FuzzyEqualsMultiplicative(nontransientTransforms.GetXScale(), nontransientTransforms.GetYScale())) {
     NS_WARNING("The x- and y-scales of the nontransient transforms should be equal");
   }
   mFrameMetrics.mTransformScale.scale = nontransientTransforms.GetXScale();
 }
 }
 }

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gfx/layers/apz/src/AsyncPanZoomController.cpp@97036ab72558 (annotated)

gfx/layers/apz/src/AsyncPanZoomController.cpp