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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 00:47:55 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 00:47:55 +0000
commit26a029d407be480d791972afb5975cf62c9360a6 (patch)
treef435a8308119effd964b339f76abb83a57c29483 /gfx/layers/apz/src/APZCTreeManager.h
parentInitial commit. (diff)
downloadfirefox-26a029d407be480d791972afb5975cf62c9360a6.tar.xz
firefox-26a029d407be480d791972afb5975cf62c9360a6.zip
Adding upstream version 124.0.1.upstream/124.0.1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 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/. */
+
+#ifndef mozilla_layers_APZCTreeManager_h
+#define mozilla_layers_APZCTreeManager_h
+
+#include <unordered_map> // for std::unordered_map
+
+#include "FocusState.h" // for FocusState
+#include "HitTestingTreeNode.h" // for HitTestingTreeNodeAutoLock
+#include "IAPZHitTester.h" // for IAPZHitTester::HitTestResult
+#include "gfxPoint.h" // for gfxPoint
+#include "mozilla/Assertions.h" // for MOZ_ASSERT_HELPER2
+#include "mozilla/DataMutex.h" // for DataMutex
+#include "mozilla/gfx/CompositorHitTestInfo.h"
+#include "mozilla/gfx/Logging.h" // for gfx::TreeLog
+#include "mozilla/gfx/Matrix.h" // for Matrix4x4
+#include "mozilla/layers/APZInputBridge.h" // for APZInputBridge
+#include "mozilla/layers/APZTestData.h" // for APZTestData
+#include "mozilla/layers/APZUtils.h" // for GeckoViewMetrics
+#include "mozilla/layers/IAPZCTreeManager.h" // for IAPZCTreeManager
+#include "mozilla/layers/ScrollbarData.h"
+#include "mozilla/layers/LayersTypes.h"
+#include "mozilla/layers/KeyboardMap.h" // for KeyboardMap
+#include "mozilla/layers/TouchCounter.h" // for TouchCounter
+#include "mozilla/layers/ZoomConstraints.h" // for ZoomConstraints
+#include "mozilla/webrender/webrender_ffi.h"
+#include "mozilla/RecursiveMutex.h" // for RecursiveMutex
+#include "mozilla/RefPtr.h" // for RefPtr
+#include "mozilla/TimeStamp.h" // for mozilla::TimeStamp
+#include "mozilla/UniquePtr.h" // for UniquePtr
+#include "nsCOMPtr.h" // for already_AddRefed
+#include "nsTArray.h"
+#include "OvershootDetector.h"
+
+namespace mozilla {
+class MultiTouchInput;
+
+namespace wr {
+class TransactionWrapper;
+class WebRenderAPI;
+} // namespace wr
+
+namespace layers {
+
+class Layer;
+class AsyncPanZoomController;
+class APZCTreeManagerParent;
+class APZSampler;
+class APZUpdater;
+class CompositorBridgeParent;
+class OverscrollHandoffChain;
+struct OverscrollHandoffState;
+class FocusTarget;
+struct FlingHandoffState;
+class InputQueue;
+struct InputBlockCallbackInfo;
+class GeckoContentController;
+class HitTestingTreeNode;
+class SampleTime;
+class WebRenderScrollDataWrapper;
+struct AncestorTransform;
+struct ScrollThumbData;
+struct ZoomTarget;
+
+/**
+ * ****************** NOTE ON LOCK ORDERING IN APZ **************************
+ *
+ * To avoid deadlock, APZ imposes and respects a global ordering on threads
+ * and locks relevant to APZ.
+ *
+ * Please see the "Threading / Locking Overview" section of
+ * gfx/docs/AsyncPanZoom.rst (hosted in rendered form at
+ * https://firefox-source-docs.mozilla.org/gfx/gfx/AsyncPanZoom.html#threading-locking-overview)
+ * for what the ordering is, and what are the rules for respecting it.
+ * **************************************************************************
+ */
+
+/**
+ * This class manages the tree of AsyncPanZoomController instances. There is one
+ * instance of this class owned by each CompositorBridgeParent, and it contains
+ * as many AsyncPanZoomController instances as there are scrollable container
+ * layers. This class generally lives on the updater thread, although some
+ * functions may be called from other threads as noted; thread safety is ensured
+ * internally.
+ *
+ * The bulk of the work of this class happens as part of the
+ * UpdateHitTestingTree function, which is when a layer tree update is received
+ * by the compositor. This function walks through the layer tree and creates a
+ * tree of HitTestingTreeNode instances to match the layer tree and for use in
+ * hit-testing on the controller thread. APZC instances may be preserved across
+ * calls to this function if the corresponding layers are still present in the
+ * layer tree.
+ *
+ * The other functions on this class are used by various pieces of client code
+ * to notify the APZC instances of events relevant to them. This includes, for
+ * example, user input events that drive panning and zooming, changes to the
+ * scroll viewport area, and changes to pan/zoom constraints.
+ *
+ * Note that the ClearTree function MUST be called when this class is no longer
+ * needed; see the method documentation for details.
+ *
+ * Behaviour of APZ is controlled by a number of preferences shown
+ * \ref APZCPrefs "here".
+ */
+class APZCTreeManager : public IAPZCTreeManager, public APZInputBridge {
+ typedef mozilla::layers::AllowedTouchBehavior AllowedTouchBehavior;
+ typedef mozilla::layers::AsyncDragMetrics AsyncDragMetrics;
+ using HitTestResult = IAPZHitTester::HitTestResult;
+
+ /*
+ * A result from APZCTreeManager::FindHandoffParent.
+ */
+ struct TargetApzcForNodeResult {
+ // The APZC to handoff overscroll to.
+ AsyncPanZoomController* mApzc;
+ // Targeting a document's root APZC from content fixed to the document.
+ bool mIsFixed;
+ };
+
+ // Helper struct to hold some state while we build the hit-testing tree. The
+ // sole purpose of this struct is to shorten the argument list to
+ // UpdateHitTestingTree. All the state that we don't need to
+ // push on the stack during recursion and pop on unwind is stored here.
+ struct TreeBuildingState;
+
+ public:
+ static mozilla::LazyLogModule sLog;
+
+ static already_AddRefed<APZCTreeManager> Create(
+ LayersId aRootLayersId, UniquePtr<IAPZHitTester> aHitTester = nullptr);
+ void SetSampler(APZSampler* aSampler);
+ void SetUpdater(APZUpdater* aUpdater);
+
+ /**
+ * Notifies this APZCTreeManager that the associated compositor is now
+ * responsible for managing another layers id, which got moved over from
+ * some other compositor. That other compositor's APZCTreeManager is also
+ * provided. This allows APZCTreeManager to transfer any necessary state
+ * from the old APZCTreeManager related to that layers id.
+ * This function must be called on the updater thread.
+ */
+ void NotifyLayerTreeAdopted(LayersId aLayersId,
+ const RefPtr<APZCTreeManager>& aOldTreeManager);
+
+ /**
+ * Notifies this APZCTreeManager that a layer tree being managed by the
+ * associated compositor has been removed/destroyed. Note that this does
+ * NOT get called during shutdown situations, when the root layer tree is
+ * also getting destroyed.
+ * This function must be called on the updater thread.
+ */
+ void NotifyLayerTreeRemoved(LayersId aLayersId);
+
+ /**
+ * Rebuild the focus state based on the focus target from the layer tree
+ * update that just occurred. This must be called on the updater thread.
+ *
+ * @param aRootLayerTreeId The layer tree ID of the root layer corresponding
+ * to this APZCTreeManager
+ * @param aOriginatingLayersId The layer tree ID of the layer corresponding to
+ * this layer tree update.
+ */
+ void UpdateFocusState(LayersId aRootLayerTreeId,
+ LayersId aOriginatingLayersId,
+ const FocusTarget& aFocusTarget);
+
+ /**
+ * Rebuild the hit-testing tree based on an incoming WebRender transaction.
+ * Preserve nodes and APZC instances where possible, but retire those whose
+ * layers are no longer in the layer tree.
+ * (Note: "layer tree" here refers to the tree of WebRenderLayerScrollData
+ * nodes sent as part of a WebRender transaction.)
+ *
+ * This must be called on the updater thread.
+ *
+ * @param aRoot The root of the (full) layer tree
+ * @param aOriginatingLayersId The layers id of the subtree that triggered
+ * this repaint, and to which aIsFirstPaint
+ * applies.
+ * @param aIsFirstPaint True if the transaction that this is called in
+ * response to included a first-paint. If this is true,
+ * the part of the tree that is affected by the
+ * first-paint flag is indicated by the
+ * aOriginatingLayersId parameter.
+ * @param aPaintSequenceNumber The sequence number of the paint that triggered
+ * this layer update. Note that every child
+ * process' layer subtree has its own sequence
+ * numbers.
+ */
+ void UpdateHitTestingTree(const WebRenderScrollDataWrapper& aRoot,
+ bool aIsFirstPaint, LayersId aOriginatingLayersId,
+ uint32_t aPaintSequenceNumber);
+
+ /**
+ * Called when webrender is enabled, from the sampler thread. This function
+ * populates the provided transaction with any async scroll offsets needed.
+ * It also advances APZ animations to the specified sample time, and requests
+ * another composite if there are still active animations.
+ * In effect it is the webrender equivalent of (part of) the code in
+ * AsyncCompositionManager.
+ */
+ void SampleForWebRender(const Maybe<VsyncId>& aVsyncId,
+ wr::TransactionWrapper& aTxn,
+ const SampleTime& aSampleTime);
+
+ /**
+ * Refer to the documentation of APZInputBridge::ReceiveInputEvent() and
+ * APZEventResult.
+ */
+ APZEventResult ReceiveInputEvent(
+ InputData& aEvent,
+ InputBlockCallback&& aCallback = InputBlockCallback()) override;
+
+ /**
+ * Set the keyboard shortcuts to use for translating keyboard events.
+ */
+ void SetKeyboardMap(const KeyboardMap& aKeyboardMap) override;
+
+ /**
+ * Kicks an animation to zoom to a rect. This may be either a zoom out or zoom
+ * in. The actual animation is done on the sampler thread after being set
+ * up. |aRect| must be given in CSS pixels, relative to the document.
+ * |aFlags| is a combination of the ZoomToRectBehavior enum values.
+ */
+ void ZoomToRect(const ScrollableLayerGuid& aGuid,
+ const ZoomTarget& aZoomTarget,
+ const uint32_t aFlags = DEFAULT_BEHAVIOR) override;
+
+ /**
+ * If we have touch listeners, this should always be called when we know
+ * definitively whether or not content has preventDefaulted any touch events
+ * that have come in. If |aPreventDefault| is true, any touch events in the
+ * queue will be discarded. This function must be called on the controller
+ * thread.
+ */
+ void ContentReceivedInputBlock(uint64_t aInputBlockId,
+ bool aPreventDefault) override;
+
+ /**
+ * When the event regions code is enabled, this function should be invoked to
+ * to confirm the target of the input block. This is only needed in cases
+ * where the initial input event of the block hit a dispatch-to-content region
+ * but is safe to call for all input blocks.
+ * The different elements in the array of targets correspond to the targets
+ * for the different touch points. In the case where the touch point has no
+ * target, or the target is not a scrollable frame, the target's |mScrollId|
+ * should be set to ScrollableLayerGuid::NULL_SCROLL_ID.
+ * Note: For mouse events that start a scrollbar drag, both SetTargetAPZC()
+ * and StartScrollbarDrag() will be called, and the calls may happen
+ * in either order. That's fine - whichever arrives first will confirm
+ * the block, and StartScrollbarDrag() will fill in the drag metrics.
+ * If the block is confirmed before we have drag metrics, some events
+ * in the drag block may be handled as no-ops until the drag metrics
+ * arrive.
+ */
+ void SetTargetAPZC(uint64_t aInputBlockId,
+ const nsTArray<ScrollableLayerGuid>& aTargets) override;
+
+ /**
+ * Updates any zoom constraints contained in the <meta name="viewport"> tag.
+ * If the |aConstraints| is Nothing() then previously-provided constraints for
+ * the given |aGuid| are cleared.
+ */
+ void UpdateZoomConstraints(
+ const ScrollableLayerGuid& aGuid,
+ const Maybe<ZoomConstraints>& aConstraints) override;
+
+ /**
+ * Calls Destroy() on all APZC instances attached to the tree, and resets the
+ * tree back to empty. This function must be called exactly once during the
+ * lifetime of this APZCTreeManager, when this APZCTreeManager is no longer
+ * needed. Failing to call this function may prevent objects from being freed
+ * properly.
+ * This must be called on the updater thread.
+ */
+ void ClearTree();
+
+ /**
+ * Sets the dpi value used by all AsyncPanZoomControllers attached to this
+ * tree manager.
+ * DPI defaults to 160 if not set using SetDPI() at any point.
+ */
+ void SetDPI(float aDpiValue) override;
+
+ /**
+ * Returns the current dpi value in use.
+ */
+ float GetDPI() const;
+
+ /**
+ * Find the hit testing node for the scrollbar thumb that matches these
+ * drag metrics. Initializes aOutThumbNode with the node, if there is one.
+ */
+ void FindScrollThumbNode(const AsyncDragMetrics& aDragMetrics,
+ LayersId aLayersId,
+ HitTestingTreeNodeAutoLock& aOutThumbNode);
+
+ /**
+ * Sets allowed touch behavior values for current touch-session for specific
+ * input block (determined by aInputBlock).
+ * Should be invoked by the widget. Each value of the aValues arrays
+ * corresponds to the different touch point that is currently active.
+ * Must be called after receiving the TOUCH_START event that starts the
+ * touch-session.
+ */
+ void SetAllowedTouchBehavior(
+ uint64_t aInputBlockId,
+ const nsTArray<TouchBehaviorFlags>& aValues) override;
+
+ void SetBrowserGestureResponse(uint64_t aInputBlockId,
+ BrowserGestureResponse aResponse) override;
+
+ /**
+ * This is a callback for AsyncPanZoomController to call when it wants to
+ * scroll in response to a touch-move event, or when it needs to hand off
+ * overscroll to the next APZC. Note that because of scroll grabbing, the
+ * first APZC to scroll may not be the one that is receiving the touch events.
+ *
+ * |aPrev| is the APZC that received the touch events triggering the scroll
+ * (in the case of an initial scroll), or the last APZC to scroll (in the
+ * case of overscroll)
+ * |aStartPoint| and |aEndPoint| are in |aPrev|'s transformed screen
+ * coordinates (i.e. the same coordinates in which touch points are given to
+ * APZCs). The amount of (over)scroll is represented by two points rather
+ * than a displacement because with certain 3D transforms, the same
+ * displacement between different points in transformed coordinates can
+ * represent different displacements in untransformed coordinates.
+ * |aOverscrollHandoffChain| is the overscroll handoff chain used for
+ * determining the order in which scroll should be handed off between
+ * APZCs
+ * |aOverscrollHandoffChainIndex| is the next position in the overscroll
+ * handoff chain that should be scrolled.
+ *
+ * aStartPoint and aEndPoint will be modified depending on how much of the
+ * scroll each APZC consumes. This is to allow the sending APZC to go into
+ * an overscrolled state if no APZC further up in the handoff chain accepted
+ * the entire scroll.
+ *
+ * The function will return true if the entire scroll was consumed, and
+ * false otherwise. As this function also modifies aStartPoint and aEndPoint,
+ * when scroll is consumed, it should always the case that this function
+ * returns true if and only if IsZero(aStartPoint - aEndPoint), using the
+ * modified aStartPoint and aEndPoint after the function returns.
+ *
+ * The way this method works is best illustrated with an example.
+ * Consider three nested APZCs, A, B, and C, with C being the innermost one.
+ * Say B is scroll-grabbing.
+ * The touch events go to C because it's the innermost one (so e.g. taps
+ * should go through C), but the overscroll handoff chain is B -> C -> A
+ * because B is scroll-grabbing.
+ * For convenience I'll refer to the three APZC objects as A, B, and C, and
+ * to the tree manager object as TM.
+ * Here's what happens when C receives a touch-move event:
+ * - C.TrackTouch() calls TM.DispatchScroll() with index = 0.
+ * - TM.DispatchScroll() calls B.AttemptScroll() (since B is at index 0 in
+ * the chain).
+ * - B.AttemptScroll() scrolls B. If there is overscroll, it calls
+ * TM.DispatchScroll() with index = 1.
+ * - TM.DispatchScroll() calls C.AttemptScroll() (since C is at index 1 in
+ * the chain)
+ * - C.AttemptScroll() scrolls C. If there is overscroll, it calls
+ * TM.DispatchScroll() with index = 2.
+ * - TM.DispatchScroll() calls A.AttemptScroll() (since A is at index 2 in
+ * the chain)
+ * - A.AttemptScroll() scrolls A. If there is overscroll, it calls
+ * TM.DispatchScroll() with index = 3.
+ * - TM.DispatchScroll() discards the rest of the scroll as there are no
+ * more elements in the chain.
+ *
+ * Note: this should be used for panning only. For handing off overscroll for
+ * a fling, use DispatchFling().
+ */
+ bool DispatchScroll(AsyncPanZoomController* aPrev,
+ ParentLayerPoint& aStartPoint,
+ ParentLayerPoint& aEndPoint,
+ OverscrollHandoffState& aOverscrollHandoffState);
+
+ /**
+ * This is a callback for AsyncPanZoomController to call when it wants to
+ * start a fling in response to a touch-end event, or when it needs to hand
+ * off a fling to the next APZC. Note that because of scroll grabbing, the
+ * first APZC to fling may not be the one that is receiving the touch events.
+ *
+ * @param aApzc the APZC that wants to start or hand off the fling
+ * @param aHandoffState a collection of state about the operation,
+ * which contains the following:
+ *
+ * mVelocity the current velocity of the fling, in |aApzc|'s screen
+ * pixels per millisecond
+ * mChain the chain of APZCs along which the fling
+ * should be handed off
+ * mIsHandoff is true if |aApzc| is handing off an existing fling (in
+ * this case the fling is given to the next APZC in the
+ * handoff chain after |aApzc|), and false is |aApzc| wants
+ * start a fling (in this case the fling is given to the
+ * first APZC in the chain)
+ *
+ * The return value is the "residual velocity", the portion of
+ * |aHandoffState.mVelocity| that was not consumed by APZCs in the
+ * handoff chain doing flings.
+ * The caller can use this value to determine whether it should consume
+ * the excess velocity by going into overscroll.
+ */
+ ParentLayerPoint DispatchFling(AsyncPanZoomController* aApzc,
+ const FlingHandoffState& aHandoffState);
+
+ void StartScrollbarDrag(const ScrollableLayerGuid& aGuid,
+ const AsyncDragMetrics& aDragMetrics) override;
+
+ bool StartAutoscroll(const ScrollableLayerGuid& aGuid,
+ const ScreenPoint& aAnchorLocation) override;
+
+ void StopAutoscroll(const ScrollableLayerGuid& aGuid) override;
+
+ /*
+ * Build the chain of APZCs that will handle overscroll for a pan starting at
+ * |aInitialTarget|.
+ */
+ RefPtr<const OverscrollHandoffChain> BuildOverscrollHandoffChain(
+ const RefPtr<AsyncPanZoomController>& aInitialTarget);
+
+ /**
+ * Function used to disable LongTap gestures.
+ *
+ * On slow running tests, drags and touch events can be misinterpreted
+ * as a long tap. This allows tests to disable long tap gesture detection.
+ */
+ void SetLongTapEnabled(bool aTapGestureEnabled) override;
+
+ APZInputBridge* InputBridge() override { return this; }
+
+ /**
+ * Add a callback to be invoked when |aInputBlockId| is ready for handling.
+ *
+ * Should only be used for input blocks that are not yet ready for handling
+ * at the time this is called. If the input block was already handled,
+ * the callback will never be called.
+ *
+ * Only one callback can be registered for an input block at a time.
+ * Subsequent attempts to register a callback for an input block will be
+ * ignored until the existing callback is triggered.
+ */
+ void AddInputBlockCallback(uint64_t aInputBlockId,
+ InputBlockCallbackInfo&& aCallbackInfo);
+
+ // Methods to help process WidgetInputEvents (or manage conversion to/from
+ // InputData)
+
+ void ProcessUnhandledEvent(LayoutDeviceIntPoint* aRefPoint,
+ ScrollableLayerGuid* aOutTargetGuid,
+ uint64_t* aOutFocusSequenceNumber,
+ LayersId* aOutLayersId) override;
+
+ void UpdateWheelTransaction(
+ LayoutDeviceIntPoint aRefPoint, EventMessage aEventMessage,
+ const Maybe<ScrollableLayerGuid>& aTargetGuid) override;
+
+ bool GetAPZTestData(LayersId aLayersId, APZTestData* aOutData);
+
+ /**
+ * Iterates over the hit testing tree, collects LayersIds and associated
+ * transforms from layer coordinate space to root coordinate space, and
+ * sends these over to the main thread of the chrome process. If the provided
+ * |aAncestor| argument is non-null, then only the transforms for layer
+ * subtrees scrolled by the aAncestor (i.e. descendants of aAncestor) will be
+ * sent.
+ */
+ void SendSubtreeTransformsToChromeMainThread(
+ const AsyncPanZoomController* aAncestor);
+
+ /**
+ * Set fixed layer margins for dynamic toolbar.
+ */
+ void SetFixedLayerMargins(ScreenIntCoord aTop, ScreenIntCoord aBottom);
+
+ /**
+ * Refer to apz::ComputeTransformForScrollThumb() for a description
+ * of the parameters.
+ */
+ static LayerToParentLayerMatrix4x4 ComputeTransformForScrollThumb(
+ const LayerToParentLayerMatrix4x4& aCurrentTransform,
+ const gfx::Matrix4x4& aScrollableContentTransform,
+ AsyncPanZoomController* aApzc, const FrameMetrics& aMetrics,
+ const ScrollbarData& aScrollbarData, bool aScrollbarIsDescendant);
+
+ /**
+ * Dispatch a flush complete notification from the repaint thread of the
+ * content controller for the given layers id.
+ */
+ static void FlushApzRepaints(LayersId aLayersId);
+
+ /**
+ * Mark |aLayersId| as having been moved from the compositor that owns this
+ * tree manager to a compositor that doesn't use APZ.
+ * See |mDetachedLayersIds| for more details.
+ */
+ void MarkAsDetached(LayersId aLayersId);
+
+ // Assert that the current thread is the sampler thread for this APZCTM.
+ void AssertOnSamplerThread();
+ // Assert that the current thread is the updater thread for this APZCTM.
+ void AssertOnUpdaterThread();
+
+ // Returns a pointer to the WebRenderAPI this APZCTreeManager is for.
+ // This might be null (for example, if WebRender is not enabled).
+ already_AddRefed<wr::WebRenderAPI> GetWebRenderAPI() const;
+
+ protected:
+ APZCTreeManager(LayersId aRootLayersId, UniquePtr<IAPZHitTester> aHitTester);
+
+ void Init();
+
+ // Protected destructor, to discourage deletion outside of Release():
+ virtual ~APZCTreeManager();
+
+ APZSampler* GetSampler() const;
+ APZUpdater* GetUpdater() const;
+
+ bool AdvanceAnimationsInternal(const MutexAutoLock& aProofOfMapLock,
+ const SampleTime& aSampleTime);
+
+ // We need to allow APZUpdater to lock and unlock this tree during a WR
+ // scene swap. We do this using private helpers to avoid exposing these
+ // functions to the world.
+ private:
+ friend class APZUpdater;
+ void LockTree() MOZ_CAPABILITY_ACQUIRE(mTreeLock);
+ void UnlockTree() MOZ_CAPABILITY_RELEASE(mTreeLock);
+
+ // Protected hooks for gtests subclass
+ virtual already_AddRefed<AsyncPanZoomController> NewAPZCInstance(
+ LayersId aLayersId, GeckoContentController* aController);
+
+ public:
+ // Public hook for gtests subclass
+ virtual SampleTime GetFrameTime();
+
+ // Also used for controlling time during tests
+ void SetTestSampleTime(const Maybe<TimeStamp>& aTime);
+
+ private:
+ mutable DataMutex<Maybe<TimeStamp>> mTestSampleTime;
+ CopyableTArray<MatrixMessage> mLastMessages;
+
+ public:
+ /* Some helper functions to find an APZC given some identifying input. These
+ functions lock the tree of APZCs while they find the right one, and then
+ return an addref'd pointer to it. This allows caller code to just use the
+ target APZC without worrying about it going away. These are public for
+ testing code and generally should not be used by other production code.
+ */
+ RefPtr<HitTestingTreeNode> GetRootNode() const;
+ HitTestResult GetTargetAPZC(const ScreenPoint& aPoint);
+ already_AddRefed<AsyncPanZoomController> GetTargetAPZC(
+ const LayersId& aLayersId,
+ const ScrollableLayerGuid::ViewID& aScrollId) const;
+ already_AddRefed<AsyncPanZoomController> GetTargetAPZC(
+ const LayersId& aLayersId, const ScrollableLayerGuid::ViewID& aScrollId,
+ const MutexAutoLock& aProofOfMapLock) const;
+ ScreenToParentLayerMatrix4x4 GetScreenToApzcTransform(
+ const AsyncPanZoomController* aApzc) const;
+ ParentLayerToScreenMatrix4x4 GetApzcToGeckoTransformForHit(
+ HitTestResult& aHitResult) const;
+ ParentLayerToScreenMatrix4x4 GetApzcToGeckoTransform(
+ const AsyncPanZoomController* aApzc,
+ const AsyncTransformComponents& aComponents) const;
+
+ /*
+ * A common utility function used for GetApzcToGeckoTransform and
+ * GetOopifApzcToRootContentApzcTransform.
+ *
+ * NOTE: The matrix returned by this function can NOT be used to convert
+ * metrics in |aStartApzc| to |aStopApzc|. If you want the conversion matrix,
+ * you will have to use either GetApzcToGeckoTransform or
+ * GetOopifApzcToRootContentApzcTransform.
+ */
+ ParentLayerToParentLayerMatrix4x4 GetApzcToApzcTransform(
+ const AsyncPanZoomController* aStartApzc,
+ const AsyncPanZoomController* aStopApzc,
+ const AsyncTransformComponents& aComponents) const;
+
+ /*
+ * Returns the matrix which transforms coordinates relative to the layout
+ * viewport of |aApzc|, to be relative to the document origin of the root
+ * content APZC of |aApzc|.
+ * |aApzc| must be the root APZC of an out-of-process iframe.
+ */
+ CSSToCSSMatrix4x4 GetOopifToRootContentTransform(
+ AsyncPanZoomController* aApzc) const;
+
+ /**
+ * Convert the given |aRect| in the document coordinates of |aApzc| to the top
+ * level document coordinates.
+ * |aApzc| must be an in-process root APZC.
+ */
+ CSSRect ConvertRectInApzcToRoot(AsyncPanZoomController* aApzc,
+ const CSSRect& aRect) const;
+
+ ScreenPoint GetCurrentMousePosition() const;
+ void SetCurrentMousePosition(const ScreenPoint& aNewPos);
+
+ /**
+ * Convert a screen point of an event targeting |aApzc| to Gecko
+ * coordinates.
+ */
+ Maybe<ScreenIntPoint> ConvertToGecko(const ScreenIntPoint& aPoint,
+ AsyncPanZoomController* aApzc);
+
+ /**
+ * Find the zoomable APZC in the same layer subtree (i.e. with the same
+ * layers id) as the given APZC.
+ */
+ already_AddRefed<AsyncPanZoomController> FindZoomableApzc(
+ AsyncPanZoomController* aStart) const;
+
+ AsyncPanZoomController* FindRootApzcFor(LayersId aLayersId) const;
+
+ ScreenMargin GetCompositorFixedLayerMargins() const;
+
+ void AdjustEventPointForDynamicToolbar(ScreenIntPoint& aEventPoint,
+ const HitTestResult& aHit);
+
+ APZScrollGeneration NewAPZScrollGeneration() {
+ // In the production code this function gets only called from the sampler
+ // thread but in tests using nsIDOMWindowUtils.setAsyncScrollOffset this
+ // function gets called from the controller thread so we need to lock the
+ // mutex for this counter.
+ MutexAutoLock lock(mScrollGenerationLock);
+ return mScrollGenerationCounter.NewAPZGeneration();
+ }
+
+ template <typename Callback>
+ void CallWithMapLock(Callback& aCallback) {
+ MutexAutoLock lock(mMapLock);
+ aCallback(lock);
+ }
+
+ private:
+ using GuidComparator = ScrollableLayerGuid::Comparator;
+ using ScrollNode = WebRenderScrollDataWrapper;
+
+ /* Helpers */
+
+ void AttachNodeToTree(HitTestingTreeNode* aNode, HitTestingTreeNode* aParent,
+ HitTestingTreeNode* aNextSibling)
+ MOZ_REQUIRES(mTreeLock);
+ already_AddRefed<AsyncPanZoomController> GetTargetAPZC(
+ const ScrollableLayerGuid& aGuid);
+ already_AddRefed<HitTestingTreeNode> GetTargetNode(
+ const ScrollableLayerGuid& aGuid, GuidComparator aComparator) const;
+ HitTestingTreeNode* FindTargetNode(HitTestingTreeNode* aNode,
+ const ScrollableLayerGuid& aGuid,
+ GuidComparator aComparator);
+ TargetApzcForNodeResult GetTargetApzcForNode(const HitTestingTreeNode* aNode);
+ TargetApzcForNodeResult FindHandoffParent(
+ const AsyncPanZoomController* aApzc);
+ /**
+ * Find the root __content__ APZC for |aLayersId|.
+ * If |aLayersId| is NOT for the LayersId for the root content, this function
+ * returns nullptr.
+ *
+ * NOTE: Only the top-level content document will have a root content APZC.
+ */
+ HitTestingTreeNode* FindRootNodeForLayersId(LayersId aLayersId) const;
+ AsyncPanZoomController* FindRootContentApzcForLayersId(
+ LayersId aLayersId) const;
+ already_AddRefed<AsyncPanZoomController> GetZoomableTarget(
+ AsyncPanZoomController* aApzc1, AsyncPanZoomController* aApzc2) const;
+ already_AddRefed<AsyncPanZoomController> CommonAncestor(
+ AsyncPanZoomController* aApzc1, AsyncPanZoomController* aApzc2) const;
+
+ struct FixedPositionInfo;
+ struct StickyPositionInfo;
+
+ // Returns true if |aNode| is a fixed layer that is fixed to the root content
+ // APZC.
+ // The map lock is required within these functions; if the map lock is already
+ // being held by the caller, the second overload should be used. If the map
+ // lock is not being held at the call site, the first overload should be used.
+ bool IsFixedToRootContent(const HitTestingTreeNode* aNode) const;
+ bool IsFixedToRootContent(const FixedPositionInfo& aFixedInfo,
+ const MutexAutoLock& aProofOfMapLock) const;
+
+ // Returns the vertical sides of |aNode| that are stuck to the root content.
+ // The map lock is required within these functions; if the map lock is already
+ // being held by the caller, the second overload should be used. If the map
+ // lock is not being held at the call site, the first overload should be used.
+ SideBits SidesStuckToRootContent(const HitTestingTreeNode* aNode,
+ AsyncTransformConsumer aMode) const;
+ SideBits SidesStuckToRootContent(const StickyPositionInfo& aStickyInfo,
+ AsyncTransformConsumer aMode,
+ const MutexAutoLock& aProofOfMapLock) const;
+
+ /**
+ * Perform hit testing for a touch-start event.
+ *
+ * @param aEvent The touch-start event.
+ *
+ * The remaining parameters are out-parameter used to communicate additional
+ * return values:
+ *
+ * @param aOutTouchBehaviors
+ * The touch behaviours that should be allowed for this touch block.
+
+ * @return The results of the hit test, including the APZC that was hit.
+ */
+ HitTestResult GetTouchInputBlockAPZC(
+ const MultiTouchInput& aEvent,
+ nsTArray<TouchBehaviorFlags>* aOutTouchBehaviors);
+
+ /**
+ * A helper structure for use by ReceiveInputEvent() and its helpers.
+ */
+ struct InputHandlingState {
+ // A reference to the event being handled.
+ InputData& mEvent;
+
+ // The value that will be returned by ReceiveInputEvent().
+ APZEventResult mResult;
+
+ // If we performed a hit-test while handling this input event, or
+ // reused the result of a previous hit-test in the input block,
+ // this is populated with the result of the hit test.
+ HitTestResult mHit;
+
+ // Called at the end of ReceiveInputEvent() to perform any final
+ // computations, and then return mResult.
+ // If the event will have a delayed result then this takes care of adding
+ // the specified callback to the APZCTreeManager.
+ APZEventResult Finish(APZCTreeManager& aTreeManager,
+ InputBlockCallback&& aCallback);
+ };
+
+ void ProcessTouchInput(InputHandlingState& aState, MultiTouchInput& aInput);
+ /**
+ * Given a mouse-down event that hit a scroll thumb node, set up APZ
+ * dragging of the scroll thumb.
+ *
+ * Must be called after the mouse event has been sent to InputQueue.
+ *
+ * @param aMouseInput The mouse-down event.
+ * @param aScrollThumbNode Tthe scroll thumb node that was hit.
+ * @param aApzc
+ * The APZC for the scroll frame scrolled by the scroll thumb, if that
+ * scroll frame is layerized. (A thumb can be layerized without its
+ * target scroll frame being layerized.) Otherwise, an enclosing APZC.
+ */
+ void SetupScrollbarDrag(MouseInput& aMouseInput,
+ const HitTestingTreeNodeAutoLock& aScrollThumbNode,
+ AsyncPanZoomController* aApzc);
+ /**
+ * Process a touch event that's part of a scrollbar touch-drag gesture.
+ *
+ * @param aInput The touch event.
+ * @param aScrollThumbNode
+ * If this is the touch-start event, the node representing the scroll
+ * thumb we are starting to drag. Otherwise nullptr.
+ * @param aHitInfo
+ * The hit-test flags for the touch input.
+ * @return See ReceiveInputEvent() for what the return value means.
+ */
+ APZEventResult ProcessTouchInputForScrollbarDrag(
+ MultiTouchInput& aInput,
+ const HitTestingTreeNodeAutoLock& aScrollThumbNode,
+ const gfx::CompositorHitTestInfo& aHitInfo);
+ void FlushRepaintsToClearScreenToGeckoTransform();
+
+ void SynthesizePinchGestureFromMouseWheel(
+ const ScrollWheelInput& aWheelInput,
+ const RefPtr<AsyncPanZoomController>& aTarget);
+
+ already_AddRefed<HitTestingTreeNode> RecycleOrCreateNode(
+ const RecursiveMutexAutoLock& aProofOfTreeLock, TreeBuildingState& aState,
+ AsyncPanZoomController* aApzc, LayersId aLayersId);
+ HitTestingTreeNode* PrepareNodeForLayer(
+ const RecursiveMutexAutoLock& aProofOfTreeLock, const ScrollNode& aLayer,
+ const FrameMetrics& aMetrics, LayersId aLayersId,
+ const Maybe<ZoomConstraints>& aZoomConstraints,
+ const AncestorTransform& aAncestorTransform, HitTestingTreeNode* aParent,
+ HitTestingTreeNode* aNextSibling, TreeBuildingState& aState);
+
+ void PrintLayerInfo(const ScrollNode& aLayer);
+
+ void NotifyScrollbarDragInitiated(uint64_t aDragBlockId,
+ const ScrollableLayerGuid& aGuid,
+ ScrollDirection aDirection) const;
+ void NotifyScrollbarDragRejected(const ScrollableLayerGuid& aGuid) const;
+ void NotifyAutoscrollRejected(const ScrollableLayerGuid& aGuid) const;
+
+ // Returns the transform that converts from |aNode|'s coordinates
+ // to the coordinates of |aNode|'s parent in the hit-testing tree. Requires
+ // the caller to hold mTreeLock.
+ LayerToParentLayerMatrix4x4 ComputeTransformForScrollThumbNode(
+ const HitTestingTreeNode* aNode) const MOZ_REQUIRES(mTreeLock);
+
+ // Look up the GeckoContentController for the given layers id.
+ static already_AddRefed<GeckoContentController> GetContentController(
+ LayersId aLayersId);
+
+ using ClippedCompositionBoundsMap =
+ std::unordered_map<ScrollableLayerGuid, ParentLayerRect,
+ ScrollableLayerGuid::HashIgnoringPresShellFn,
+ ScrollableLayerGuid::EqualIgnoringPresShellFn>;
+ // This is a recursive function that populates `aDestMap` with the clipped
+ // composition bounds for the APZC corresponding to `aGuid` and returns those
+ // bounds as a convenience. It recurses to also populate `aDestMap` with that
+ // APZC's ancestors. In order to do this it needs to access mApzcMap
+ // and therefore requires the caller to hold the map lock.
+ ParentLayerRect ComputeClippedCompositionBounds(
+ const MutexAutoLock& aProofOfMapLock,
+ ClippedCompositionBoundsMap& aDestMap, ScrollableLayerGuid aGuid);
+
+ ScreenMargin GetCompositorFixedLayerMargins(
+ const MutexAutoLock& aProofOfMapLock) const;
+
+ protected:
+ /* The input queue where input events are held until we know enough to
+ * figure out where they're going. Protected so gtests can access it.
+ */
+ RefPtr<InputQueue> mInputQueue;
+
+ /** A lock that protects mApzcMap, mScrollThumbInfo, mRootScrollbarInfo,
+ * mFixedPositionInfo, and mStickyPositionInfo.
+ */
+ mutable mozilla::Mutex mMapLock;
+
+ private:
+ /* Layers id for the root CompositorBridgeParent that owns this
+ * APZCTreeManager. */
+ LayersId mRootLayersId;
+
+ /* Pointer to the APZSampler instance that is bound to this APZCTreeManager.
+ * The sampler has a RefPtr to this class, and this non-owning raw pointer
+ * back to the APZSampler is nulled out in the sampler's destructor, so this
+ * pointer should always be valid.
+ */
+ APZSampler* MOZ_NON_OWNING_REF mSampler;
+ /* Pointer to the APZUpdater instance that is bound to this APZCTreeManager.
+ * The updater has a RefPtr to this class, and this non-owning raw pointer
+ * back to the APZUpdater is nulled out in the updater's destructor, so this
+ * pointer should always be valid.
+ */
+ APZUpdater* MOZ_NON_OWNING_REF mUpdater;
+
+ /* Whenever walking or mutating the tree rooted at mRootNode, mTreeLock must
+ * be held. This lock does not need to be held while manipulating a single
+ * APZC instance in isolation (that is, if its tree pointers are not being
+ * accessed or mutated). The lock also needs to be held when accessing the
+ * mRootNode instance variable, as that is considered part of the APZC tree
+ * management state.
+ * IMPORTANT: See the note about lock ordering at the top of this file. */
+ mutable mozilla::RecursiveMutex mTreeLock;
+ RefPtr<HitTestingTreeNode> mRootNode MOZ_GUARDED_BY(mTreeLock);
+
+ /*
+ * A set of LayersIds for which APZCTM should only send empty
+ * MatrixMessages via NotifyLayerTransform().
+ * This is used in cases where a tab has been transferred to a non-APZ
+ * compositor (and thus will not receive MatrixMessages reflecting its new
+ * transforms) and we need to make sure it doesn't get stuck with transforms
+ * from its old tree manager (us).
+ * Acquire mTreeLock before accessing this.
+ */
+ std::unordered_set<LayersId, LayersId::HashFn> mDetachedLayersIds
+ MOZ_GUARDED_BY(mTreeLock);
+
+ /**
+ * Helper structure to store a bunch of things in mApzcMap so that they can
+ * be used from the sampler thread.
+ */
+ struct ApzcMapData {
+ // A pointer to the APZC itself
+ RefPtr<AsyncPanZoomController> apzc;
+ // The parent APZC's guid, or Nothing() if there is no parent
+ Maybe<ScrollableLayerGuid> parent;
+ };
+
+ /**
+ * A map for quick access to get some APZC data by guid, without having to
+ * acquire the tree lock. mMapLock must be acquired while accessing or
+ * modifying mApzcMap.
+ */
+ std::unordered_map<ScrollableLayerGuid, ApzcMapData,
+ ScrollableLayerGuid::HashIgnoringPresShellFn,
+ ScrollableLayerGuid::EqualIgnoringPresShellFn>
+ mApzcMap;
+ /**
+ * A helper structure to store all the information needed to compute the
+ * async transform for a scrollthumb on the sampler thread.
+ */
+ struct ScrollThumbInfo {
+ uint64_t mThumbAnimationId;
+ CSSTransformMatrix mThumbTransform;
+ ScrollbarData mThumbData;
+ ScrollableLayerGuid mTargetGuid;
+ CSSTransformMatrix mTargetTransform;
+ bool mTargetIsAncestor;
+
+ ScrollThumbInfo(const uint64_t& aThumbAnimationId,
+ const CSSTransformMatrix& aThumbTransform,
+ const ScrollbarData& aThumbData,
+ const ScrollableLayerGuid& aTargetGuid,
+ const CSSTransformMatrix& aTargetTransform,
+ bool aTargetIsAncestor)
+ : mThumbAnimationId(aThumbAnimationId),
+ mThumbTransform(aThumbTransform),
+ mThumbData(aThumbData),
+ mTargetGuid(aTargetGuid),
+ mTargetTransform(aTargetTransform),
+ mTargetIsAncestor(aTargetIsAncestor) {
+ MOZ_ASSERT(mTargetGuid.mScrollId == mThumbData.mTargetViewId);
+ }
+ };
+ /**
+ * If this APZCTreeManager is being used with WebRender, this vector gets
+ * populated during a layers update. It holds a package of information needed
+ * to compute and set the async transforms on scroll thumbs. This information
+ * is extracted from the HitTestingTreeNodes for the WebRender case because
+ * accessing the HitTestingTreeNodes requires holding the tree lock which
+ * we cannot do on the WR sampler thread. mScrollThumbInfo, however, can
+ * be accessed while just holding the mMapLock which is safe to do on the
+ * sampler thread.
+ * mMapLock must be acquired while accessing or modifying mScrollThumbInfo.
+ */
+ std::vector<ScrollThumbInfo> mScrollThumbInfo;
+
+ /**
+ * A helper structure to store all the information needed to compute the
+ * async transform for a scrollthumb on the sampler thread.
+ */
+ struct RootScrollbarInfo {
+ uint64_t mScrollbarAnimationId;
+ ScrollDirection mScrollDirection;
+
+ RootScrollbarInfo(const uint64_t& aScrollbarAnimationId,
+ const ScrollDirection aScrollDirection)
+ : mScrollbarAnimationId(aScrollbarAnimationId),
+ mScrollDirection(aScrollDirection) {}
+ };
+ /**
+ * If this APZCTreeManager is being used with WebRender, this vector gets
+ * populated during a layers update. It holds a package of information needed
+ * to compute and set the async transforms on root scrollbars. This
+ * information is extracted from the HitTestingTreeNodes for the WebRender
+ * case because accessing the HitTestingTreeNodes requires holding the tree
+ * lock which we cannot do on the WR sampler thread. mRootScrollbarInfo,
+ * however, can be accessed while just holding the mMapLock which is safe to
+ * do on the sampler thread.
+ * mMapLock must be acquired while accessing or modifying mRootScrollbarInfo.
+ */
+ std::vector<RootScrollbarInfo> mRootScrollbarInfo;
+
+ /**
+ * A helper structure to store all the information needed to compute the
+ * async transform for a fixed position element on the sampler thread.
+ */
+ struct FixedPositionInfo {
+ Maybe<uint64_t> mFixedPositionAnimationId;
+ SideBits mFixedPosSides;
+ ScrollableLayerGuid::ViewID mFixedPosTarget;
+ LayersId mLayersId;
+
+ explicit FixedPositionInfo(const HitTestingTreeNode* aNode);
+ };
+ /**
+ * If this APZCTreeManager is being used with WebRender, this vector gets
+ * populated during a layers update. It holds a package of information needed
+ * to compute and set the async transforms on fixed position content. This
+ * information is extracted from the HitTestingTreeNodes for the WebRender
+ * case because accessing the HitTestingTreeNodes requires holding the tree
+ * lock which we cannot do on the WR sampler thread. mFixedPositionInfo,
+ * however, can be accessed while just holding the mMapLock which is safe to
+ * do on the sampler thread. mMapLock must be acquired while accessing or
+ * modifying mFixedPositionInfo.
+ */
+ std::vector<FixedPositionInfo> mFixedPositionInfo;
+
+ /**
+ * A helper structure to store all the information needed to compute the
+ * async transform for a sticky position element on the sampler thread.
+ */
+ struct StickyPositionInfo {
+ Maybe<uint64_t> mStickyPositionAnimationId;
+ SideBits mFixedPosSides;
+ ScrollableLayerGuid::ViewID mStickyPosTarget;
+ LayersId mLayersId;
+ LayerRectAbsolute mStickyScrollRangeInner;
+ LayerRectAbsolute mStickyScrollRangeOuter;
+
+ explicit StickyPositionInfo(const HitTestingTreeNode* aNode);
+ };
+ /**
+ * If this APZCTreeManager is being used with WebRender, this vector gets
+ * populated during a layers update. It holds a package of information needed
+ * to compute and set the async transforms on sticky position content. This
+ * information is extracted from the HitTestingTreeNodes for the WebRender
+ * case because accessing the HitTestingTreeNodes requires holding the tree
+ * lock which we cannot do on the WR sampler thread. mStickyPositionInfo,
+ * however, can be accessed while just holding the mMapLock which is safe to
+ * do on the sampler thread. mMapLock must be acquired while accessing or
+ * modifying mStickyPositionInfo.
+ */
+ std::vector<StickyPositionInfo> mStickyPositionInfo;
+
+ /* Holds the zoom constraints for scrollable layers, as determined by the
+ * the main-thread gecko code. This can only be accessed on the updater
+ * thread. */
+ std::unordered_map<ScrollableLayerGuid, ZoomConstraints,
+ ScrollableLayerGuid::HashIgnoringPresShellFn,
+ ScrollableLayerGuid::EqualIgnoringPresShellFn>
+ mZoomConstraints;
+ /* A list of keyboard shortcuts to use for translating keyboard inputs into
+ * keyboard actions. This is gathered on the main thread from XBL bindings.
+ * This must only be accessed on the controller thread.
+ */
+ KeyboardMap mKeyboardMap;
+ /* This tracks the focus targets of chrome and content and whether we have
+ * a current focus target or whether we are waiting for a new confirmation.
+ */
+ FocusState mFocusState;
+ /* This tracks the hit test result info for the current touch input block.
+ * In particular, it tracks the target APZC, the hit test flags, and the
+ * fixed pos sides. This is populated at the start of a touch block based
+ * on the hit-test result, and used for subsequent touch events in the block.
+ * This allows touch points to move outside the thing they started on, but
+ * still have the touch events delivered to the same initial APZC. This will
+ * only ever be touched on the input delivery thread, and so does not require
+ * locking.
+ */
+ HitTestResult mTouchBlockHitResult;
+ /* Sometimes we want to ignore all touches except one. In such cases, this
+ * is set to the identifier of the touch we are not ignoring; in other cases,
+ * this is set to -1.
+ */
+ int32_t mRetainedTouchIdentifier;
+ /* This tracks whether the current input block represents a touch-drag of
+ * a scrollbar. In this state, touch events are forwarded to content as touch
+ * events, but converted to mouse events before going into InputQueue and
+ * being handled by an APZC (to reuse the APZ code for scrollbar dragging
+ * with a mouse).
+ */
+ bool mInScrollbarTouchDrag;
+ /* Tracks the number of touch points we are tracking that are currently on
+ * the screen. */
+ TouchCounter mTouchCounter;
+ /* If a tap gesture event sent directly by widget code (rather than gesture
+ * detected from touch events by APZ) is being processed, this stores the
+ * result of hit testing for that tap gesture event.
+ */
+ HitTestResult mTapGestureHitResult;
+ /* Stores the current mouse position in screen coordinates.
+ */
+ mutable DataMutex<ScreenPoint> mCurrentMousePosition;
+ /* Extra margins that should be applied to content that fixed wrt. the
+ * RCD-RSF, to account for the dynamic toolbar.
+ * Acquire mMapLock before accessing this.
+ */
+ ScreenMargin mCompositorFixedLayerMargins;
+ /* Similar to above |mCompositorFixedLayerMargins|. But this value is the
+ * margins on the main-thread at the last time position:fixed elements were
+ * updated during the dynamic toolbar transitions.
+ * Acquire mMapLock before accessing this.
+ */
+ ScreenMargin mGeckoFixedLayerMargins;
+ /* For logging the APZC tree for debugging (enabled by the apz.printtree
+ * pref). The purpose of using LOG_CRITICAL is so that you don't also need to
+ * change the gfx.logging.level pref to see the output. */
+ gfx::TreeLog<gfx::LOG_CRITICAL> mApzcTreeLog;
+
+ class CheckerboardFlushObserver;
+ friend class CheckerboardFlushObserver;
+ RefPtr<CheckerboardFlushObserver> mFlushObserver;
+
+ // Map from layers id to APZTestData. Accesses and mutations must be
+ // protected by the mTestDataLock.
+ std::unordered_map<LayersId, UniquePtr<APZTestData>, LayersId::HashFn>
+ mTestData;
+ mutable mozilla::Mutex mTestDataLock;
+
+ // A state machine that tries to record how much users are overshooting
+ // their desired scroll destination while using the scrollwheel.
+ OvershootDetector mOvershootDetector;
+
+ // This must only be touched on the controller thread.
+ float mDPI;
+
+ friend class IAPZHitTester;
+ UniquePtr<IAPZHitTester> mHitTester;
+
+ // NOTE: This ScrollGenerationCounter needs to be per APZCTreeManager since
+ // the generation is bumped up on the sampler theread which is per
+ // APZCTreeManager.
+ ScrollGenerationCounter mScrollGenerationCounter;
+ mozilla::Mutex mScrollGenerationLock;
+
+#if defined(MOZ_WIDGET_ANDROID)
+ private:
+ // Last Frame metrics sent to java through UIController.
+ GeckoViewMetrics mLastRootMetrics;
+#endif // defined(MOZ_WIDGET_ANDROID)
+};
+
+} // namespace layers
+} // namespace mozilla
+
+#endif // mozilla_layers_PanZoomController_h