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Diffstat (limited to 'gfx/layers/apz/src/APZCTreeManager.cpp')
| -rw-r--r-- | gfx/layers/apz/src/APZCTreeManager.cpp | 3967 |
1 files changed, 3967 insertions, 0 deletions
diff --git a/gfx/layers/apz/src/APZCTreeManager.cpp b/gfx/layers/apz/src/APZCTreeManager.cpp new file mode 100644 index 0000000000..208aba114e --- /dev/null +++ b/gfx/layers/apz/src/APZCTreeManager.cpp @@ -0,0 +1,3967 @@ +/* -*- 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/. */ + +#include <stack> +#include <unordered_set> +#include "APZCTreeManager.h" +#include "AsyncPanZoomController.h" +#include "Compositor.h" // for Compositor +#include "DragTracker.h" // for DragTracker +#include "GenericFlingAnimation.h" // for FLING_LOG +#include "HitTestingTreeNode.h" // for HitTestingTreeNode +#include "InputBlockState.h" // for InputBlockState +#include "InputData.h" // for InputData, etc +#include "Layers.h" // for Layer, etc +#include "mozilla/RecursiveMutex.h" +#include "mozilla/dom/MouseEventBinding.h" // for MouseEvent constants +#include "mozilla/dom/BrowserParent.h" // for AreRecordReplayTabsActive +#include "mozilla/dom/Touch.h" // for Touch +#include "mozilla/gfx/CompositorHitTestInfo.h" +#include "mozilla/gfx/LoggingConstants.h" +#include "mozilla/gfx/gfxVars.h" // for gfxVars +#include "mozilla/gfx/GPUParent.h" // for GPUParent +#include "mozilla/gfx/Logging.h" // for gfx::TreeLog +#include "mozilla/gfx/Point.h" // for Point +#include "mozilla/layers/APZSampler.h" // for APZSampler +#include "mozilla/layers/APZThreadUtils.h" // for AssertOnControllerThread, etc +#include "mozilla/layers/APZUpdater.h" // for APZUpdater +#include "mozilla/layers/APZUtils.h" // for AsyncTransform +#include "mozilla/layers/AsyncDragMetrics.h" // for AsyncDragMetrics +#include "mozilla/layers/CompositorBridgeParent.h" // for CompositorBridgeParent, etc +#include "mozilla/layers/LayerMetricsWrapper.h" +#include "mozilla/layers/MatrixMessage.h" +#include "mozilla/layers/UiCompositorControllerParent.h" +#include "mozilla/layers/WebRenderScrollDataWrapper.h" +#include "mozilla/MouseEvents.h" +#include "mozilla/mozalloc.h" // for operator new +#include "mozilla/Preferences.h" // for Preferences +#include "mozilla/StaticPrefs_accessibility.h" +#include "mozilla/StaticPrefs_apz.h" +#include "mozilla/StaticPrefs_layout.h" +#include "mozilla/ToString.h" +#include "mozilla/TouchEvents.h" +#include "mozilla/EventStateManager.h" // for WheelPrefs +#include "mozilla/webrender/WebRenderAPI.h" +#include "nsDebug.h" // for NS_WARNING +#include "nsPoint.h" // for nsIntPoint +#include "nsThreadUtils.h" // for NS_IsMainThread +#include "OverscrollHandoffState.h" // for OverscrollHandoffState +#include "TreeTraversal.h" // for ForEachNode, BreadthFirstSearch, etc +#include "Units.h" // for ParentlayerPixel +#include "GestureEventListener.h" // for GestureEventListener::setLongTapEnabled +#include "UnitTransforms.h" // for ViewAs + +static mozilla::LazyLogModule sApzMgrLog("apz.manager"); +#define APZCTM_LOG(...) MOZ_LOG(sApzMgrLog, LogLevel::Debug, (__VA_ARGS__)) + +static mozilla::LazyLogModule sApzKeyLog("apz.key"); +#define APZ_KEY_LOG(...) MOZ_LOG(sApzKeyLog, LogLevel::Debug, (__VA_ARGS__)) + +namespace mozilla { +namespace layers { + +using mozilla::gfx::CompositorHitTestDispatchToContent; +using mozilla::gfx::CompositorHitTestFlags; +using mozilla::gfx::CompositorHitTestInfo; +using mozilla::gfx::CompositorHitTestInvisibleToHit; +using mozilla::gfx::LOG_DEFAULT; + +typedef mozilla::gfx::Point Point; +typedef mozilla::gfx::Point4D Point4D; +typedef mozilla::gfx::Matrix4x4 Matrix4x4; + +typedef CompositorBridgeParent::LayerTreeState LayerTreeState; + +struct APZCTreeManager::TreeBuildingState { + TreeBuildingState(LayersId aRootLayersId, bool aIsFirstPaint, + LayersId aOriginatingLayersId, APZTestData* aTestData, + uint32_t aPaintSequence) + : mIsFirstPaint(aIsFirstPaint), + mOriginatingLayersId(aOriginatingLayersId), + mPaintLogger(aTestData, aPaintSequence) { + CompositorBridgeParent::CallWithIndirectShadowTree( + aRootLayersId, [this](LayerTreeState& aState) -> void { + mCompositorController = aState.GetCompositorController(); + mInProcessSharingController = aState.InProcessSharingController(); + }); + } + + typedef std::unordered_map<AsyncPanZoomController*, gfx::Matrix4x4> + DeferredTransformMap; + + // State that doesn't change as we recurse in the tree building + RefPtr<CompositorController> mCompositorController; + RefPtr<MetricsSharingController> mInProcessSharingController; + const bool mIsFirstPaint; + const LayersId mOriginatingLayersId; + const APZPaintLogHelper mPaintLogger; + + // State that is updated as we perform the tree build + + // A list of nodes that need to be destroyed at the end of the tree building. + // This is initialized with all nodes in the old tree, and nodes are removed + // from it as we reuse them in the new tree. + nsTArray<RefPtr<HitTestingTreeNode>> mNodesToDestroy; + + // This map is populated as we place APZCs into the new tree. Its purpose is + // to facilitate re-using the same APZC for different layers that scroll + // together (and thus have the same ScrollableLayerGuid). The presShellId + // doesn't matter for this purpose, and we move the map to the APZCTreeManager + // after we're done building, so it's useful to have the presshell-ignoring + // map for that. + std::unordered_map<ScrollableLayerGuid, ApzcMapData, + ScrollableLayerGuid::HashIgnoringPresShellFn, + ScrollableLayerGuid::EqualIgnoringPresShellFn> + mApzcMap; + + // This is populated with all the HitTestingTreeNodes that are scroll thumbs + // and have a scrollthumb animation id (which indicates that they need to be + // sampled for WebRender on the sampler thread). + std::vector<HitTestingTreeNode*> mScrollThumbs; + // This is populated with all the scroll target nodes. We use in conjunction + // with mScrollThumbs to build APZCTreeManager::mScrollThumbInfo. + std::unordered_map<ScrollableLayerGuid, HitTestingTreeNode*, + ScrollableLayerGuid::HashIgnoringPresShellFn, + ScrollableLayerGuid::EqualIgnoringPresShellFn> + mScrollTargets; + + // As the tree is traversed, the top element of this stack tracks whether + // the parent scroll node has a perspective transform. + std::stack<bool> mParentHasPerspective; + + // During the tree building process, the perspective transform component + // of the ancestor transforms of some APZCs can be "deferred" to their + // children, meaning they are added to the children's ancestor transforms + // instead. Those deferred transforms are tracked here. + DeferredTransformMap mPerspectiveTransformsDeferredToChildren; + + // As we recurse down through the tree, this picks up the zoom animation id + // from a node in the layer tree, and propagates it downwards to the nearest + // APZC instance that is for an RCD node. Generally it will be set on the + // root node of the layers (sub-)tree, which may not be same as the RCD node + // for the subtree, and so we need this mechanism to ensure it gets propagated + // to the RCD's APZC instance. Once it is set on the APZC instance, the value + // is cleared back to Nothing(). Note that this is only used in the WebRender + // codepath. + Maybe<uint64_t> mZoomAnimationId; + + // See corresponding members of APZCTreeManager. These are the same thing, but + // on the tree-walking state. They are populated while walking the tree in + // a layers update, and then moved into APZCTreeManager. + std::vector<FixedPositionInfo> mFixedPositionInfo; + std::vector<RootScrollbarInfo> mRootScrollbarInfo; + std::vector<StickyPositionInfo> mStickyPositionInfo; + + // As we recurse down through reflayers in the tree, this picks up the + // cumulative EventRegionsOverride flags from the reflayers, and is used to + // apply them to descendant layers. + std::stack<EventRegionsOverride> mOverrideFlags; +}; + +class APZCTreeManager::CheckerboardFlushObserver : public nsIObserver { + public: + NS_DECL_ISUPPORTS + NS_DECL_NSIOBSERVER + + explicit CheckerboardFlushObserver(APZCTreeManager* aTreeManager) + : mTreeManager(aTreeManager) { + MOZ_ASSERT(NS_IsMainThread()); + nsCOMPtr<nsIObserverService> obsSvc = + mozilla::services::GetObserverService(); + MOZ_ASSERT(obsSvc); + if (obsSvc) { + obsSvc->AddObserver(this, "APZ:FlushActiveCheckerboard", false); + } + } + + void Unregister() { + MOZ_ASSERT(NS_IsMainThread()); + nsCOMPtr<nsIObserverService> obsSvc = + mozilla::services::GetObserverService(); + if (obsSvc) { + obsSvc->RemoveObserver(this, "APZ:FlushActiveCheckerboard"); + } + mTreeManager = nullptr; + } + + protected: + virtual ~CheckerboardFlushObserver() = default; + + private: + RefPtr<APZCTreeManager> mTreeManager; +}; + +NS_IMPL_ISUPPORTS(APZCTreeManager::CheckerboardFlushObserver, nsIObserver) + +NS_IMETHODIMP +APZCTreeManager::CheckerboardFlushObserver::Observe(nsISupports* aSubject, + const char* aTopic, + const char16_t*) { + MOZ_ASSERT(NS_IsMainThread()); + MOZ_ASSERT(mTreeManager.get()); + + RecursiveMutexAutoLock lock(mTreeManager->mTreeLock); + if (mTreeManager->mRootNode) { + ForEachNode<ReverseIterator>( + mTreeManager->mRootNode.get(), [](HitTestingTreeNode* aNode) { + if (aNode->IsPrimaryHolder()) { + MOZ_ASSERT(aNode->GetApzc()); + aNode->GetApzc()->FlushActiveCheckerboardReport(); + } + }); + } + if (XRE_IsGPUProcess()) { + if (gfx::GPUParent* gpu = gfx::GPUParent::GetSingleton()) { + nsCString topic("APZ:FlushActiveCheckerboard:Done"); + Unused << gpu->SendNotifyUiObservers(topic); + } + } else { + MOZ_ASSERT(XRE_IsParentProcess()); + nsCOMPtr<nsIObserverService> obsSvc = + mozilla::services::GetObserverService(); + if (obsSvc) { + obsSvc->NotifyObservers(nullptr, "APZ:FlushActiveCheckerboard:Done", + nullptr); + } + } + return NS_OK; +} + +/** + * A RAII class used for setting the focus sequence number on input events + * as they are being processed. Any input event is assumed to be potentially + * focus changing unless explicitly marked otherwise. + */ +class MOZ_RAII AutoFocusSequenceNumberSetter { + public: + AutoFocusSequenceNumberSetter(FocusState& aFocusState, InputData& aEvent) + : mFocusState(aFocusState), mEvent(aEvent), mMayChangeFocus(true) {} + + void MarkAsNonFocusChanging() { mMayChangeFocus = false; } + + ~AutoFocusSequenceNumberSetter() { + if (mMayChangeFocus) { + mFocusState.ReceiveFocusChangingEvent(); + + APZ_KEY_LOG( + "Marking input with type=%d as focus changing with seq=%" PRIu64 "\n", + static_cast<int>(mEvent.mInputType), + mFocusState.LastAPZProcessedEvent()); + } else { + APZ_KEY_LOG( + "Marking input with type=%d as non focus changing with seq=%" PRIu64 + "\n", + static_cast<int>(mEvent.mInputType), + mFocusState.LastAPZProcessedEvent()); + } + + mEvent.mFocusSequenceNumber = mFocusState.LastAPZProcessedEvent(); + } + + private: + FocusState& mFocusState; + InputData& mEvent; + bool mMayChangeFocus; +}; + +APZCTreeManager::APZCTreeManager(LayersId aRootLayersId, bool aIsUsingWebRender) + : mTestSampleTime(Nothing(), "APZCTreeManager::mTestSampleTime"), + mInputQueue(new InputQueue()), + mRootLayersId(aRootLayersId), + mSampler(nullptr), + mUpdater(nullptr), + mTreeLock("APZCTreeLock"), + mMapLock("APZCMapLock"), + mRetainedTouchIdentifier(-1), + mInScrollbarTouchDrag(false), + mCurrentMousePosition(ScreenPoint(), + "APZCTreeManager::mCurrentMousePosition"), + mApzcTreeLog("apzctree"), + mTestDataLock("APZTestDataLock"), + mDPI(160.0), + mIsUsingWebRender(aIsUsingWebRender) { + RefPtr<APZCTreeManager> self(this); + NS_DispatchToMainThread(NS_NewRunnableFunction( + "layers::APZCTreeManager::APZCTreeManager", + [self] { self->mFlushObserver = new CheckerboardFlushObserver(self); })); + AsyncPanZoomController::InitializeGlobalState(); + mApzcTreeLog.ConditionOnPrefFunction(StaticPrefs::apz_printtree); +} + +APZCTreeManager::~APZCTreeManager() = default; + +void APZCTreeManager::SetSampler(APZSampler* aSampler) { + // We're either setting the sampler or clearing it + MOZ_ASSERT((mSampler == nullptr) != (aSampler == nullptr)); + mSampler = aSampler; +} + +void APZCTreeManager::SetUpdater(APZUpdater* aUpdater) { + // We're either setting the updater or clearing it + MOZ_ASSERT((mUpdater == nullptr) != (aUpdater == nullptr)); + mUpdater = aUpdater; +} + +void APZCTreeManager::NotifyLayerTreeAdopted( + LayersId aLayersId, const RefPtr<APZCTreeManager>& aOldApzcTreeManager) { + AssertOnUpdaterThread(); + + if (aOldApzcTreeManager) { + aOldApzcTreeManager->mFocusState.RemoveFocusTarget(aLayersId); + // While we could move the focus target information from the old APZC tree + // manager into this one, it's safer to not do that, as we'll probably have + // that information repopulated soon anyway (on the next layers update). + } + + UniquePtr<APZTestData> adoptedData; + if (aOldApzcTreeManager) { + MutexAutoLock lock(aOldApzcTreeManager->mTestDataLock); + auto it = aOldApzcTreeManager->mTestData.find(aLayersId); + if (it != aOldApzcTreeManager->mTestData.end()) { + adoptedData = std::move(it->second); + aOldApzcTreeManager->mTestData.erase(it); + } + } + if (adoptedData) { + MutexAutoLock lock(mTestDataLock); + mTestData[aLayersId] = std::move(adoptedData); + } +} + +void APZCTreeManager::NotifyLayerTreeRemoved(LayersId aLayersId) { + AssertOnUpdaterThread(); + + mFocusState.RemoveFocusTarget(aLayersId); + + { // scope lock + MutexAutoLock lock(mTestDataLock); + mTestData.erase(aLayersId); + } +} + +AsyncPanZoomController* APZCTreeManager::NewAPZCInstance( + LayersId aLayersId, GeckoContentController* aController) { + return new AsyncPanZoomController( + aLayersId, this, mInputQueue, aController, + AsyncPanZoomController::USE_GESTURE_DETECTOR); +} + +void APZCTreeManager::SetTestSampleTime(const Maybe<TimeStamp>& aTime) { + auto testSampleTime = mTestSampleTime.Lock(); + testSampleTime.ref() = aTime; +} + +SampleTime APZCTreeManager::GetFrameTime() { + auto testSampleTime = mTestSampleTime.Lock(); + if (testSampleTime.ref()) { + return SampleTime::FromTest(*testSampleTime.ref()); + } + return SampleTime::FromNow(); +} + +void APZCTreeManager::SetAllowedTouchBehavior( + uint64_t aInputBlockId, const nsTArray<TouchBehaviorFlags>& aValues) { + APZThreadUtils::AssertOnControllerThread(); + + mInputQueue->SetAllowedTouchBehavior(aInputBlockId, aValues); +} + +template <class ScrollNode> +void // ScrollNode is a LayerMetricsWrapper or a WebRenderScrollDataWrapper +APZCTreeManager::UpdateHitTestingTreeImpl(const ScrollNode& aRoot, + bool aIsFirstPaint, + LayersId aOriginatingLayersId, + uint32_t aPaintSequenceNumber) { + RecursiveMutexAutoLock lock(mTreeLock); + + // For testing purposes, we log some data to the APZTestData associated with + // the layers id that originated this update. + APZTestData* testData = nullptr; + if (StaticPrefs::apz_test_logging_enabled()) { + MutexAutoLock lock(mTestDataLock); + UniquePtr<APZTestData> ptr = MakeUnique<APZTestData>(); + auto result = + mTestData.insert(std::make_pair(aOriginatingLayersId, std::move(ptr))); + testData = result.first->second.get(); + testData->StartNewPaint(aPaintSequenceNumber); + } + + TreeBuildingState state(mRootLayersId, aIsFirstPaint, aOriginatingLayersId, + testData, aPaintSequenceNumber); + + // We do this business with collecting the entire tree into an array because + // otherwise it's very hard to determine which APZC instances need to be + // destroyed. In the worst case, there are two scenarios: (a) a layer with an + // APZC is removed from the layer tree and (b) a layer with an APZC is moved + // in the layer tree from one place to a completely different place. In + // scenario (a) we would want to destroy the APZC while walking the layer tree + // and noticing that the layer/APZC is no longer there. But if we do that then + // we run into a problem in scenario (b) because we might encounter that layer + // later during the walk. To handle both of these we have to 'remember' that + // the layer was not found, and then do the destroy only at the end of the + // tree walk after we are sure that the layer was removed and not just + // transplanted elsewhere. Doing that as part of a recursive tree walk is hard + // and so maintaining a list and removing APZCs that are still alive is much + // simpler. + ForEachNode<ReverseIterator>(mRootNode.get(), + [&state](HitTestingTreeNode* aNode) { + state.mNodesToDestroy.AppendElement(aNode); + }); + mRootNode = nullptr; + mAsyncZoomContainerSubtree = Nothing(); + int asyncZoomContainerNestingDepth = 0; + bool haveNestedAsyncZoomContainers = false; + nsTArray<LayersId> subtreesWithRootContentOutsideAsyncZoomContainer; + + if (aRoot) { + std::unordered_set<LayersId, LayersId::HashFn> seenLayersIds; + std::stack<gfx::TreeAutoIndent<LOG_DEFAULT>> indents; + std::stack<AncestorTransform> ancestorTransforms; + HitTestingTreeNode* parent = nullptr; + HitTestingTreeNode* next = nullptr; + LayersId layersId = mRootLayersId; + seenLayersIds.insert(mRootLayersId); + ancestorTransforms.push(AncestorTransform()); + state.mParentHasPerspective.push(false); + state.mOverrideFlags.push(EventRegionsOverride::NoOverride); + + mApzcTreeLog << "[start]\n"; + mTreeLock.AssertCurrentThreadIn(); + + ForEachNode<ReverseIterator>( + aRoot, + [&](ScrollNode aLayerMetrics) { + mApzcTreeLog << aLayerMetrics.Name() << '\t'; + + if (aLayerMetrics.IsAsyncZoomContainer()) { + if (asyncZoomContainerNestingDepth > 0) { + haveNestedAsyncZoomContainers = true; + } + mAsyncZoomContainerSubtree = Some(layersId); + ++asyncZoomContainerNestingDepth; + } + + if (aLayerMetrics.Metrics().IsRootContent()) { + MutexAutoLock lock(mMapLock); + mGeckoFixedLayerMargins = + aLayerMetrics.Metrics().GetFixedLayerMargins(); + } else { + MOZ_ASSERT(aLayerMetrics.Metrics().GetFixedLayerMargins() == + ScreenMargin(), + "fixed-layer-margins should be 0 on non-root layer"); + } + + // Note that this check happens after the potential increment of + // asyncZoomContainerNestingDepth, to allow the root content + // metadata to be on the same node as the async zoom container. + if (aLayerMetrics.Metrics().IsRootContent() && + asyncZoomContainerNestingDepth == 0) { + subtreesWithRootContentOutsideAsyncZoomContainer.AppendElement( + layersId); + } + + HitTestingTreeNode* node = PrepareNodeForLayer( + lock, aLayerMetrics, aLayerMetrics.Metrics(), layersId, + ancestorTransforms.top(), parent, next, state); + MOZ_ASSERT(node); + AsyncPanZoomController* apzc = node->GetApzc(); + aLayerMetrics.SetApzc(apzc); + + // GetScrollbarAnimationId is only set when webrender is enabled, + // which limits the extra thumb mapping work to the webrender-enabled + // case where it is needed. + // Note also that when webrender is enabled, a "valid" animation id + // is always nonzero, so we don't need to worry about handling the + // case where WR is enabled and the animation id is zero. + if (node->GetScrollbarAnimationId()) { + if (node->IsScrollThumbNode()) { + state.mScrollThumbs.push_back(node); + } else if (node->IsScrollbarContainerNode()) { + // Only scrollbar containers for the root have an animation id. + state.mRootScrollbarInfo.emplace_back( + *(node->GetScrollbarAnimationId()), + node->GetScrollbarDirection()); + } + } + + // GetFixedPositionAnimationId is only set when webrender is enabled. + if (node->GetFixedPositionAnimationId().isSome()) { + state.mFixedPositionInfo.emplace_back(node); + } + // GetStickyPositionAnimationId is only set when webrender is enabled. + if (node->GetStickyPositionAnimationId().isSome()) { + state.mStickyPositionInfo.emplace_back(node); + } + if (apzc && node->IsPrimaryHolder()) { + state.mScrollTargets[apzc->GetGuid()] = node; + } + + mApzcTreeLog << '\n'; + + // Accumulate the CSS transform between layers that have an APZC. + // In the terminology of the big comment above + // APZCTreeManager::GetScreenToApzcTransform, if we are at layer M, + // then aAncestorTransform is NC * OC * PC, and we left-multiply MC + // and compute ancestorTransform to be MC * NC * OC * PC. This gets + // passed down as the ancestor transform to layer L when we recurse + // into the children below. If we are at a layer with an APZC, such as + // P, then we reset the ancestorTransform to just PC, to start the new + // accumulation as we go down. + AncestorTransform currentTransform{ + aLayerMetrics.GetTransform(), + aLayerMetrics.TransformIsPerspective()}; + if (!apzc) { + currentTransform = currentTransform * ancestorTransforms.top(); + } + ancestorTransforms.push(currentTransform); + + // Note that |node| at this point will not have any children, + // otherwise we we would have to set next to node->GetFirstChild(). + MOZ_ASSERT(!node->GetFirstChild()); + parent = node; + next = nullptr; + + // Update the layersId if we have a new one + if (Maybe<LayersId> newLayersId = aLayerMetrics.GetReferentId()) { + layersId = *newLayersId; + seenLayersIds.insert(layersId); + + // Propagate any event region override flags down into all + // descendant nodes from the reflayer that has the flag. This is an + // optimization to avoid having to walk up the tree to check the + // override flags. Note that we don't keep the flags on the reflayer + // itself, because the semantics of the flags are that they apply + // to all content in the layer subtree being referenced. This + // matters with the WR hit-test codepath, because this reflayer may + // be just one of many nodes associated with a particular APZC, and + // calling GetTargetNode with a guid may return any one of the + // nodes. If different nodes have different flags on them that can + // make the WR hit-test result incorrect, but being strict about + // only putting the flags on descendant layers avoids this problem. + state.mOverrideFlags.push(state.mOverrideFlags.top() | + aLayerMetrics.GetEventRegionsOverride()); + } + + indents.push(gfx::TreeAutoIndent<LOG_DEFAULT>(mApzcTreeLog)); + state.mParentHasPerspective.push( + aLayerMetrics.TransformIsPerspective()); + }, + [&](ScrollNode aLayerMetrics) { + if (aLayerMetrics.IsAsyncZoomContainer()) { + --asyncZoomContainerNestingDepth; + } + if (aLayerMetrics.GetReferentId()) { + state.mOverrideFlags.pop(); + } + + next = parent; + parent = parent->GetParent(); + layersId = next->GetLayersId(); + ancestorTransforms.pop(); + indents.pop(); + state.mParentHasPerspective.pop(); + }); + + mApzcTreeLog << "[end]\n"; + + MOZ_ASSERT( + !mAsyncZoomContainerSubtree || + !subtreesWithRootContentOutsideAsyncZoomContainer.Contains( + *mAsyncZoomContainerSubtree), + "If there is an async zoom container, all scroll nodes with root " + "content scroll metadata should be inside it"); + MOZ_ASSERT(!haveNestedAsyncZoomContainers, + "Should not have nested async zoom container"); + + // If we have perspective transforms deferred to children, do another + // walk of the tree and actually apply them to the children. + // We can't do this "as we go" in the previous traversal, because by the + // time we realize we need to defer a perspective transform for an APZC, + // we may already have processed a previous layer (including children + // found in its subtree) that shares that APZC. + if (!state.mPerspectiveTransformsDeferredToChildren.empty()) { + ForEachNode<ReverseIterator>( + mRootNode.get(), [&state](HitTestingTreeNode* aNode) { + AsyncPanZoomController* apzc = aNode->GetApzc(); + if (!apzc) { + return; + } + if (!aNode->IsPrimaryHolder()) { + return; + } + + AsyncPanZoomController* parent = apzc->GetParent(); + if (!parent) { + return; + } + + auto it = + state.mPerspectiveTransformsDeferredToChildren.find(parent); + if (it != state.mPerspectiveTransformsDeferredToChildren.end()) { + apzc->SetAncestorTransform(AncestorTransform{ + it->second * apzc->GetAncestorTransform(), false}); + } + }); + } + + // Remove any layers ids for which we no longer have content from + // mDetachedLayersIds. + for (auto iter = mDetachedLayersIds.begin(); + iter != mDetachedLayersIds.end();) { + // unordered_set::erase() invalidates the iterator pointing to the + // element being erased, but returns an iterator to the next element. + if (seenLayersIds.find(*iter) == seenLayersIds.end()) { + iter = mDetachedLayersIds.erase(iter); + } else { + ++iter; + } + } + } + + // We do not support tree structures where the root node has siblings. + MOZ_ASSERT(!(mRootNode && mRootNode->GetPrevSibling())); + + { // scope lock and update our mApzcMap before we destroy all the unused + // APZC instances + MutexAutoLock lock(mMapLock); + mApzcMap = std::move(state.mApzcMap); + + for (auto& mapping : mApzcMap) { + AsyncPanZoomController* parent = mapping.second.apzc->GetParent(); + mapping.second.parent = parent ? Some(parent->GetGuid()) : Nothing(); + } + + mScrollThumbInfo.clear(); + // For non-webrender, state.mScrollThumbs will be empty so this will be a + // no-op. + for (HitTestingTreeNode* thumb : state.mScrollThumbs) { + MOZ_ASSERT(thumb->IsScrollThumbNode()); + ScrollableLayerGuid targetGuid(thumb->GetLayersId(), 0, + thumb->GetScrollTargetId()); + auto it = state.mScrollTargets.find(targetGuid); + if (it == state.mScrollTargets.end()) { + // It could be that |thumb| is a scrollthumb for content which didn't + // have an APZC, for example if the content isn't layerized. Regardless, + // we can't async-scroll it so we don't need to worry about putting it + // in mScrollThumbInfo. + continue; + } + HitTestingTreeNode* target = it->second; + mScrollThumbInfo.emplace_back( + *(thumb->GetScrollbarAnimationId()), thumb->GetTransform(), + thumb->GetScrollbarData(), targetGuid, target->GetTransform(), + target->IsAncestorOf(thumb)); + } + + mRootScrollbarInfo = std::move(state.mRootScrollbarInfo); + mFixedPositionInfo = std::move(state.mFixedPositionInfo); + mStickyPositionInfo = std::move(state.mStickyPositionInfo); + } + + for (size_t i = 0; i < state.mNodesToDestroy.Length(); i++) { + APZCTM_LOG("Destroying node at %p with APZC %p\n", + state.mNodesToDestroy[i].get(), + state.mNodesToDestroy[i]->GetApzc()); + state.mNodesToDestroy[i]->Destroy(); + } + + APZCTM_LOG("APZCTreeManager (%p)\n", this); + if (mRootNode && MOZ_LOG_TEST(sApzMgrLog, LogLevel::Debug)) { + mRootNode->Dump(" "); + } + SendSubtreeTransformsToChromeMainThread(nullptr); +} + +void APZCTreeManager::UpdateFocusState(LayersId aRootLayerTreeId, + LayersId aOriginatingLayersId, + const FocusTarget& aFocusTarget) { + AssertOnUpdaterThread(); + + if (!StaticPrefs::apz_keyboard_enabled_AtStartup()) { + return; + } + + mFocusState.Update(aRootLayerTreeId, aOriginatingLayersId, aFocusTarget); +} + +void APZCTreeManager::UpdateHitTestingTree(Layer* aRoot, bool aIsFirstPaint, + LayersId aOriginatingLayersId, + uint32_t aPaintSequenceNumber) { + AssertOnUpdaterThread(); + + LayerMetricsWrapper root(aRoot); + UpdateHitTestingTreeImpl(root, aIsFirstPaint, aOriginatingLayersId, + aPaintSequenceNumber); +} + +void APZCTreeManager::UpdateHitTestingTree( + const WebRenderScrollDataWrapper& aScrollWrapper, bool aIsFirstPaint, + LayersId aOriginatingLayersId, uint32_t aPaintSequenceNumber) { + AssertOnUpdaterThread(); + + UpdateHitTestingTreeImpl(aScrollWrapper, aIsFirstPaint, aOriginatingLayersId, + aPaintSequenceNumber); +} + +void APZCTreeManager::SampleForWebRender(const Maybe<VsyncId>& aVsyncId, + wr::TransactionWrapper& aTxn, + const SampleTime& aSampleTime) { + AssertOnSamplerThread(); + MutexAutoLock lock(mMapLock); + + RefPtr<WebRenderBridgeParent> wrBridgeParent; + RefPtr<CompositorController> controller; + CompositorBridgeParent::CallWithIndirectShadowTree( + mRootLayersId, [&](LayerTreeState& aState) -> void { + controller = aState.GetCompositorController(); + wrBridgeParent = aState.mWrBridge; + }); + + bool activeAnimations = AdvanceAnimationsInternal(lock, aSampleTime); + if (activeAnimations && controller) { + controller->ScheduleRenderOnCompositorThread(); + } + + nsTArray<wr::WrTransformProperty> transforms; + + // Sample async transforms on scrollable layers. + for (const auto& mapping : mApzcMap) { + AsyncPanZoomController* apzc = mapping.second.apzc; + + const AsyncTransformComponents asyncTransformComponents = + apzc->GetZoomAnimationId() + ? AsyncTransformComponents{AsyncTransformComponent::eLayout} + : LayoutAndVisual; + ParentLayerPoint layerTranslation = + apzc->GetCurrentAsyncTransform(AsyncPanZoomController::eForCompositing, + asyncTransformComponents) + .mTranslation; + + if (Maybe<CompositionPayload> payload = apzc->NotifyScrollSampling()) { + if (wrBridgeParent && aVsyncId) { + wrBridgeParent->AddPendingScrollPayload(*payload, *aVsyncId); + } + } + + if (Maybe<uint64_t> zoomAnimationId = apzc->GetZoomAnimationId()) { + // for now we only support zooming on root content APZCs + MOZ_ASSERT(apzc->IsRootContent()); + + LayoutDeviceToParentLayerScale zoom = apzc->GetCurrentPinchZoomScale( + AsyncPanZoomController::eForCompositing); + + AsyncTransform asyncVisualTransform = apzc->GetCurrentAsyncTransform( + AsyncPanZoomController::eForCompositing, + AsyncTransformComponents{AsyncTransformComponent::eVisual}); + + transforms.AppendElement(wr::ToWrTransformProperty( + *zoomAnimationId, LayoutDeviceToParentLayerMatrix4x4::Scaling( + zoom.scale, zoom.scale, 1.0f) * + AsyncTransformComponentMatrix::Translation( + asyncVisualTransform.mTranslation))); + + aTxn.UpdateIsTransformAsyncZooming(*zoomAnimationId, + apzc->IsAsyncZooming()); + } + + layerTranslation = + apzc->GetOverscrollTransform(AsyncPanZoomController::eForCompositing) + .TransformPoint(layerTranslation); + + // If layerTranslation includes only the layout component of the async + // transform then it has not been scaled by the async zoom, so we want to + // divide it by the resolution. If layerTranslation includes the visual + // component, then we should use the pinch zoom scale, which includes the + // async zoom. However, we only use LayoutAndVisual for non-zoomable APZCs, + // so it makes no difference. + LayoutDeviceToParentLayerScale resolution = + apzc->GetCumulativeResolution().ToScaleFactor() * + LayerToParentLayerScale(1.0f); + // The positive translation means the painted content is supposed to + // move down (or to the right), and that corresponds to a reduction in + // the scroll offset. Since we are effectively giving WR the async + // scroll delta here, we want to negate the translation. + LayoutDevicePoint asyncScrollDelta = -layerTranslation / resolution; + aTxn.UpdateScrollPosition(wr::AsPipelineId(apzc->GetGuid().mLayersId), + apzc->GetGuid().mScrollId, + wr::ToLayoutPoint(asyncScrollDelta)); + +#if defined(MOZ_WIDGET_ANDROID) + // Send the root frame metrics to java through the UIController + RefPtr<UiCompositorControllerParent> uiController = + UiCompositorControllerParent::GetFromRootLayerTreeId(mRootLayersId); + if (uiController && + apzc->UpdateRootFrameMetricsIfChanged(mLastRootMetrics)) { + uiController->NotifyUpdateScreenMetrics(mLastRootMetrics); + } +#endif + } + + // Now collect all the async transforms needed for the scrollthumbs. + for (const ScrollThumbInfo& info : mScrollThumbInfo) { + auto it = mApzcMap.find(info.mTargetGuid); + if (it == mApzcMap.end()) { + // It could be that |info| is a scrollthumb for content which didn't + // have an APZC, for example if the content isn't layerized. Regardless, + // we can't async-scroll it so we don't need to worry about putting it + // in mScrollThumbInfo. + continue; + } + AsyncPanZoomController* scrollTargetApzc = it->second.apzc; + MOZ_ASSERT(scrollTargetApzc); + LayerToParentLayerMatrix4x4 transform = + scrollTargetApzc->CallWithLastContentPaintMetrics( + [&](const FrameMetrics& aMetrics) { + return ComputeTransformForScrollThumb( + info.mThumbTransform * AsyncTransformMatrix(), + info.mTargetTransform.ToUnknownMatrix(), scrollTargetApzc, + aMetrics, info.mThumbData, info.mTargetIsAncestor, nullptr); + }); + transforms.AppendElement( + wr::ToWrTransformProperty(info.mThumbAnimationId, transform)); + } + + // Move the root scrollbar in response to the dynamic toolbar transition. + for (const RootScrollbarInfo& info : mRootScrollbarInfo) { + // We only care about the horizontal scrollbar. + if (info.mScrollDirection == ScrollDirection::eHorizontal) { + ScreenPoint translation = + apz::ComputeFixedMarginsOffset(GetCompositorFixedLayerMargins(lock), + SideBits::eBottom, ScreenMargin()); + + LayerToParentLayerMatrix4x4 transform = + LayerToParentLayerMatrix4x4::Translation(ViewAs<ParentLayerPixel>( + translation, PixelCastJustification::ScreenIsParentLayerForRoot)); + + transforms.AppendElement( + wr::ToWrTransformProperty(info.mScrollbarAnimationId, transform)); + } + } + + for (const FixedPositionInfo& info : mFixedPositionInfo) { + MOZ_ASSERT(info.mFixedPositionAnimationId.isSome()); + if (!IsFixedToRootContent(info, lock)) { + continue; + } + + ScreenPoint translation = apz::ComputeFixedMarginsOffset( + GetCompositorFixedLayerMargins(lock), info.mFixedPosSides, + mGeckoFixedLayerMargins); + + LayerToParentLayerMatrix4x4 transform = + LayerToParentLayerMatrix4x4::Translation(ViewAs<ParentLayerPixel>( + translation, PixelCastJustification::ScreenIsParentLayerForRoot)); + + transforms.AppendElement( + wr::ToWrTransformProperty(*info.mFixedPositionAnimationId, transform)); + } + + for (const StickyPositionInfo& info : mStickyPositionInfo) { + MOZ_ASSERT(info.mStickyPositionAnimationId.isSome()); + SideBits sides = SidesStuckToRootContent(info, lock); + if (sides == SideBits::eNone) { + continue; + } + + ScreenPoint translation = apz::ComputeFixedMarginsOffset( + GetCompositorFixedLayerMargins(lock), sides, + // For sticky layers, we don't need to factor + // mGeckoFixedLayerMargins because Gecko doesn't shift the + // position of sticky elements for dynamic toolbar movements. + ScreenMargin()); + + LayerToParentLayerMatrix4x4 transform = + LayerToParentLayerMatrix4x4::Translation(ViewAs<ParentLayerPixel>( + translation, PixelCastJustification::ScreenIsParentLayerForRoot)); + + transforms.AppendElement( + wr::ToWrTransformProperty(*info.mStickyPositionAnimationId, transform)); + } + + aTxn.AppendTransformProperties(transforms); +} + +bool APZCTreeManager::AdvanceAnimations(const SampleTime& aSampleTime) { + MutexAutoLock lock(mMapLock); + return AdvanceAnimationsInternal(lock, aSampleTime); +} + +ParentLayerRect APZCTreeManager::ComputeClippedCompositionBounds( + const MutexAutoLock& aProofOfMapLock, ClippedCompositionBoundsMap& aDestMap, + ScrollableLayerGuid aGuid) { + if (auto iter = aDestMap.find(aGuid); iter != aDestMap.end()) { + // We already computed it for this one, early-exit. This might happen + // because on a later iteration of mApzcMap we might encounter an ancestor + // of an APZC that we processed on an earlier iteration. In this case we + // would have computed the ancestor's clipped composition bounds when + // recursing up on the earlier iteration. + return iter->second; + } + + ParentLayerRect bounds = mApzcMap[aGuid].apzc->GetCompositionBounds(); + const auto& mapEntry = mApzcMap.find(aGuid); + MOZ_ASSERT(mapEntry != mApzcMap.end()); + if (mapEntry->second.parent.isNothing()) { + // Recursion base case, where the APZC with guid `aGuid` has no parent. + // In this case, we don't need to clip `bounds` any further and can just + // early exit. + aDestMap.emplace(aGuid, bounds); + return bounds; + } + + ScrollableLayerGuid parentGuid = mapEntry->second.parent.value(); + auto parentBoundsEntry = aDestMap.find(parentGuid); + // If aDestMap doesn't contain the parent entry yet, we recurse to compute + // that one first. + ParentLayerRect parentClippedBounds = + (parentBoundsEntry == aDestMap.end()) + ? ComputeClippedCompositionBounds(aProofOfMapLock, aDestMap, + parentGuid) + : parentBoundsEntry->second; + + // The parent layer's async transform applies to the current layer to take + // `bounds` into the same coordinate space as `parentClippedBounds`. However, + // we're going to do the inverse operation and unapply this transform to + // `parentClippedBounds` to bring it into the same coordinate space as + // `bounds`. + AsyncTransform appliesToLayer = + mApzcMap[parentGuid].apzc->GetCurrentAsyncTransform( + AsyncPanZoomController::eForCompositing); + + // Do the unapplication + LayerRect parentClippedBoundsInParentLayerSpace = + (parentClippedBounds - appliesToLayer.mTranslation) / + appliesToLayer.mScale; + + // And then clip `bounds` by the parent's comp bounds in the current space. + bounds = bounds.Intersect( + ViewAs<ParentLayerPixel>(parentClippedBoundsInParentLayerSpace, + PixelCastJustification::MovingDownToChildren)); + + // Done! + aDestMap.emplace(aGuid, bounds); + return bounds; +} + +bool APZCTreeManager::AdvanceAnimationsInternal( + const MutexAutoLock& aProofOfMapLock, const SampleTime& aSampleTime) { + ClippedCompositionBoundsMap clippedCompBounds; + bool activeAnimations = false; + for (const auto& mapping : mApzcMap) { + AsyncPanZoomController* apzc = mapping.second.apzc; + // Note that this call is recursive, but it early-exits if called again + // with the same guid. So this loop is still amortized O(n) with respect to + // the number of APZCs. + ParentLayerRect clippedBounds = ComputeClippedCompositionBounds( + aProofOfMapLock, clippedCompBounds, mapping.first); + + apzc->ReportCheckerboard(aSampleTime, clippedBounds); + activeAnimations |= apzc->AdvanceAnimations(aSampleTime); + } + return activeAnimations; +} + +// Compute the clip region to be used for a layer with an APZC. This function +// is only called for layers which actually have scrollable metrics and an APZC. +template <class ScrollNode> +Maybe<ParentLayerIntRegion> APZCTreeManager::ComputeClipRegion( + const LayersId& aLayersId, const ScrollNode& aLayer) { + Maybe<ParentLayerIntRegion> clipRegion; + if (aLayer.GetClipRect()) { + clipRegion.emplace(*aLayer.GetClipRect()); + } else if (aLayer.Metrics().IsRootContent() && + mAsyncZoomContainerSubtree == Some(aLayersId)) { + // If we are using containerless scrolling, part of the root content + // layers' async transform has been lifted to the async zoom container + // layer. The composition bounds clip, which applies after the async + // transform, needs to be lifted too. Layout code already takes care of + // this for us, we just need to not mess it up by introducing a + // composition bounds clip here, so we leave the clip empty. + } else { + // if there is no clip on this layer (which should only happen for the + // root scrollable layer in a process, or for some of the LayerMetrics + // expansions of a multi-metrics layer), fall back to using the comp + // bounds which should be equivalent. + clipRegion.emplace(RoundedToInt(aLayer.Metrics().GetCompositionBounds())); + } + + return clipRegion; +} + +template <class ScrollNode> +void APZCTreeManager::PrintAPZCInfo(const ScrollNode& aLayer, + const AsyncPanZoomController* apzc) { + const FrameMetrics& metrics = aLayer.Metrics(); + std::stringstream guidStr; + guidStr << apzc->GetGuid(); + mApzcTreeLog << "APZC " << guidStr.str() + << "\tcb=" << metrics.GetCompositionBounds() + << "\tsr=" << metrics.GetScrollableRect() + << (metrics.IsScrollInfoLayer() ? "\tscrollinfo" : "") + << (apzc->HasScrollgrab() ? "\tscrollgrab" : "") << "\t" + << aLayer.Metadata().GetContentDescription().get(); +} + +void APZCTreeManager::AttachNodeToTree(HitTestingTreeNode* aNode, + HitTestingTreeNode* aParent, + HitTestingTreeNode* aNextSibling) { + if (aNextSibling) { + aNextSibling->SetPrevSibling(aNode); + } else if (aParent) { + aParent->SetLastChild(aNode); + } else { + MOZ_ASSERT(!mRootNode); + mRootNode = aNode; + aNode->MakeRoot(); + } +} + +template <class ScrollNode> +static EventRegions GetEventRegions(const ScrollNode& aLayer) { + if (aLayer.Metrics().IsScrollInfoLayer()) { + ParentLayerIntRect compositionBounds( + RoundedToInt(aLayer.Metrics().GetCompositionBounds())); + nsIntRegion hitRegion(compositionBounds.ToUnknownRect()); + EventRegions eventRegions(hitRegion); + eventRegions.mDispatchToContentHitRegion = eventRegions.mHitRegion; + return eventRegions; + } + return aLayer.GetEventRegions(); +} + +already_AddRefed<HitTestingTreeNode> APZCTreeManager::RecycleOrCreateNode( + const RecursiveMutexAutoLock& aProofOfTreeLock, TreeBuildingState& aState, + AsyncPanZoomController* aApzc, LayersId aLayersId) { + // Find a node without an APZC and return it. Note that unless the layer tree + // actually changes, this loop should generally do an early-return on the + // first iteration, so it should be cheap in the common case. + for (int32_t i = aState.mNodesToDestroy.Length() - 1; i >= 0; i--) { + RefPtr<HitTestingTreeNode> node = aState.mNodesToDestroy[i]; + if (node->IsRecyclable(aProofOfTreeLock)) { + aState.mNodesToDestroy.RemoveElementAt(i); + node->RecycleWith(aProofOfTreeLock, aApzc, aLayersId); + return node.forget(); + } + } + RefPtr<HitTestingTreeNode> node = + new HitTestingTreeNode(aApzc, false, aLayersId); + return node.forget(); +} + +void APZCTreeManager::StartScrollbarDrag(const ScrollableLayerGuid& aGuid, + const AsyncDragMetrics& aDragMetrics) { + APZThreadUtils::AssertOnControllerThread(); + + RefPtr<AsyncPanZoomController> apzc = GetTargetAPZC(aGuid); + if (!apzc) { + NotifyScrollbarDragRejected(aGuid); + return; + } + + uint64_t inputBlockId = aDragMetrics.mDragStartSequenceNumber; + mInputQueue->ConfirmDragBlock(inputBlockId, apzc, aDragMetrics); +} + +bool APZCTreeManager::StartAutoscroll(const ScrollableLayerGuid& aGuid, + const ScreenPoint& aAnchorLocation) { + APZThreadUtils::AssertOnControllerThread(); + + RefPtr<AsyncPanZoomController> apzc = GetTargetAPZC(aGuid); + if (!apzc) { + if (XRE_IsGPUProcess()) { + // If we're in the compositor process, the "return false" will be + // ignored because the query comes over the PAPZCTreeManager protocol + // via an async message. In this case, send an explicit rejection + // message to content. + NotifyAutoscrollRejected(aGuid); + } + return false; + } + + apzc->StartAutoscroll(aAnchorLocation); + return true; +} + +void APZCTreeManager::StopAutoscroll(const ScrollableLayerGuid& aGuid) { + APZThreadUtils::AssertOnControllerThread(); + + if (RefPtr<AsyncPanZoomController> apzc = GetTargetAPZC(aGuid)) { + apzc->StopAutoscroll(); + } +} + +void APZCTreeManager::NotifyScrollbarDragInitiated( + uint64_t aDragBlockId, const ScrollableLayerGuid& aGuid, + ScrollDirection aDirection) const { + RefPtr<GeckoContentController> controller = + GetContentController(aGuid.mLayersId); + if (controller) { + controller->NotifyAsyncScrollbarDragInitiated(aDragBlockId, aGuid.mScrollId, + aDirection); + } +} + +void APZCTreeManager::NotifyScrollbarDragRejected( + const ScrollableLayerGuid& aGuid) const { + RefPtr<GeckoContentController> controller = + GetContentController(aGuid.mLayersId); + if (controller) { + controller->NotifyAsyncScrollbarDragRejected(aGuid.mScrollId); + } +} + +void APZCTreeManager::NotifyAutoscrollRejected( + const ScrollableLayerGuid& aGuid) const { + RefPtr<GeckoContentController> controller = + GetContentController(aGuid.mLayersId); + MOZ_ASSERT(controller); + controller->NotifyAsyncAutoscrollRejected(aGuid.mScrollId); +} + +template <class ScrollNode> +void SetHitTestData(HitTestingTreeNode* aNode, const ScrollNode& aLayer, + const Maybe<ParentLayerIntRegion>& aClipRegion, + const EventRegionsOverride& aOverrideFlags) { + aNode->SetHitTestData(GetEventRegions(aLayer), aLayer.GetVisibleRegion(), + aLayer.GetRemoteDocumentSize(), + aLayer.GetTransformTyped(), aClipRegion, aOverrideFlags, + aLayer.IsBackfaceHidden(), + !!aLayer.IsAsyncZoomContainer()); +} + +template <class ScrollNode> +HitTestingTreeNode* APZCTreeManager::PrepareNodeForLayer( + const RecursiveMutexAutoLock& aProofOfTreeLock, const ScrollNode& aLayer, + const FrameMetrics& aMetrics, LayersId aLayersId, + const AncestorTransform& aAncestorTransform, HitTestingTreeNode* aParent, + HitTestingTreeNode* aNextSibling, TreeBuildingState& aState) { + bool needsApzc = true; + if (!aMetrics.IsScrollable()) { + needsApzc = false; + } + + // XXX: As a future optimization we can probably stick these things on the + // TreeBuildingState, and update them as we change layers id during the + // traversal + RefPtr<GeckoContentController> geckoContentController; + RefPtr<MetricsSharingController> crossProcessSharingController; + CompositorBridgeParent::CallWithIndirectShadowTree( + aLayersId, [&](LayerTreeState& lts) -> void { + geckoContentController = lts.mController; + crossProcessSharingController = lts.CrossProcessSharingController(); + }); + + if (!geckoContentController) { + needsApzc = false; + } + + bool parentHasPerspective = aState.mParentHasPerspective.top(); + + if (Maybe<uint64_t> zoomAnimationId = aLayer.GetZoomAnimationId()) { + aState.mZoomAnimationId = zoomAnimationId; + } + + RefPtr<HitTestingTreeNode> node = nullptr; + if (!needsApzc) { + // Note: if layer properties must be propagated to nodes, RecvUpdate in + // LayerTransactionParent.cpp must ensure that APZ will be notified + // when those properties change. + node = RecycleOrCreateNode(aProofOfTreeLock, aState, nullptr, aLayersId); + AttachNodeToTree(node, aParent, aNextSibling); + SetHitTestData(node, aLayer, + (!parentHasPerspective && aLayer.GetClipRect()) + ? Some(ParentLayerIntRegion(*aLayer.GetClipRect())) + : Nothing(), + aState.mOverrideFlags.top()); + node->SetScrollbarData(aLayer.GetScrollbarAnimationId(), + aLayer.GetScrollbarData()); + node->SetFixedPosData(aLayer.GetFixedPositionScrollContainerId(), + aLayer.GetFixedPositionSides(), + aLayer.GetFixedPositionAnimationId()); + node->SetStickyPosData(aLayer.GetStickyScrollContainerId(), + aLayer.GetStickyScrollRangeOuter(), + aLayer.GetStickyScrollRangeInner(), + aLayer.GetStickyPositionAnimationId()); + return node; + } + + AsyncPanZoomController* apzc = nullptr; + // If we get here, aLayer is a scrollable layer and somebody + // has registered a GeckoContentController for it, so we need to ensure + // it has an APZC instance to manage its scrolling. + + // aState.mApzcMap allows reusing the exact same APZC instance for different + // layers with the same FrameMetrics data. This is needed because in some + // cases content that is supposed to scroll together is split into multiple + // layers because of e.g. non-scrolling content interleaved in z-index order. + ScrollableLayerGuid guid(aLayersId, aMetrics.GetPresShellId(), + aMetrics.GetScrollId()); + auto insertResult = aState.mApzcMap.insert(std::make_pair( + guid, + ApzcMapData{static_cast<AsyncPanZoomController*>(nullptr), Nothing()})); + if (!insertResult.second) { + apzc = insertResult.first->second.apzc; + PrintAPZCInfo(aLayer, apzc); + } + APZCTM_LOG("Found APZC %p for layer %p with identifiers %" PRIx64 " %" PRId64 + "\n", + apzc, aLayer.GetLayer(), uint64_t(guid.mLayersId), guid.mScrollId); + + // If we haven't encountered a layer already with the same metrics, then we + // need to do the full reuse-or-make-an-APZC algorithm, which is contained + // inside the block below. + if (apzc == nullptr) { + apzc = aLayer.GetApzc(); + + // If the content represented by the scrollable layer has changed (which may + // be possible because of DLBI heuristics) then we don't want to keep using + // the same old APZC for the new content. Also, when reparenting a tab into + // a new window a layer might get moved to a different layer tree with a + // different APZCTreeManager. In these cases we don't want to reuse the same + // APZC, so null it out so we run through the code to find another one or + // create one. + if (apzc && (!apzc->Matches(guid) || !apzc->HasTreeManager(this))) { + apzc = nullptr; + } + + // See if we can find an APZC from the previous tree that matches the + // ScrollableLayerGuid from this layer. If there is one, then we know that + // the layout of the page changed causing the layer tree to be rebuilt, but + // the underlying content for the APZC is still there somewhere. Therefore, + // we want to find the APZC instance and continue using it here. + // + // We particularly want to find the primary-holder node from the previous + // tree that matches, because we don't want that node to get destroyed. If + // it does get destroyed, then the APZC will get destroyed along with it by + // definition, but we want to keep that APZC around in the new tree. + // We leave non-primary-holder nodes in the destroy list because we don't + // care about those nodes getting destroyed. + for (size_t i = 0; i < aState.mNodesToDestroy.Length(); i++) { + RefPtr<HitTestingTreeNode> n = aState.mNodesToDestroy[i]; + if (n->IsPrimaryHolder() && n->GetApzc() && n->GetApzc()->Matches(guid)) { + node = n; + if (apzc != nullptr) { + // If there is an APZC already then it should match the one from the + // old primary-holder node + MOZ_ASSERT(apzc == node->GetApzc()); + } + apzc = node->GetApzc(); + break; + } + } + + // The APZC we get off the layer may have been destroyed previously if the + // layer was inactive or omitted from the layer tree for whatever reason + // from a layers update. If it later comes back it will have a reference to + // a destroyed APZC and so we need to throw that out and make a new one. + bool newApzc = (apzc == nullptr || apzc->IsDestroyed()); + if (newApzc) { + apzc = NewAPZCInstance(aLayersId, geckoContentController); + apzc->SetCompositorController(aState.mCompositorController.get()); + if (crossProcessSharingController) { + apzc->SetMetricsSharingController(crossProcessSharingController); + } else { + apzc->SetMetricsSharingController( + aState.mInProcessSharingController.get()); + } + MOZ_ASSERT(node == nullptr); + node = new HitTestingTreeNode(apzc, true, aLayersId); + } else { + // If we are re-using a node for this layer clear the tree pointers + // so that it doesn't continue pointing to nodes that might no longer + // be in the tree. These pointers will get reset properly as we continue + // building the tree. Also remove it from the set of nodes that are going + // to be destroyed, because it's going to remain active. + aState.mNodesToDestroy.RemoveElement(node); + node->SetPrevSibling(nullptr); + node->SetLastChild(nullptr); + } + + if (aMetrics.IsRootContent()) { + apzc->SetZoomAnimationId(aState.mZoomAnimationId); + aState.mZoomAnimationId = Nothing(); + } + + APZCTM_LOG( + "Using APZC %p for layer %p with identifiers %" PRIx64 " %" PRId64 "\n", + apzc, aLayer.GetLayer(), uint64_t(aLayersId), aMetrics.GetScrollId()); + + apzc->NotifyLayersUpdated(aLayer.Metadata(), aState.mIsFirstPaint, + aLayersId == aState.mOriginatingLayersId); + + // Since this is the first time we are encountering an APZC with this guid, + // the node holding it must be the primary holder. It may be newly-created + // or not, depending on whether it went through the newApzc branch above. + MOZ_ASSERT(node->IsPrimaryHolder() && node->GetApzc() && + node->GetApzc()->Matches(guid)); + + Maybe<ParentLayerIntRegion> clipRegion = + parentHasPerspective ? Nothing() : ComputeClipRegion(aLayersId, aLayer); + SetHitTestData(node, aLayer, clipRegion, aState.mOverrideFlags.top()); + apzc->SetAncestorTransform(aAncestorTransform); + + PrintAPZCInfo(aLayer, apzc); + + // Bind the APZC instance into the tree of APZCs + AttachNodeToTree(node, aParent, aNextSibling); + + // For testing, log the parent scroll id of every APZC that has a + // parent. This allows test code to reconstruct the APZC tree. + // Note that we currently only do this for APZCs in the layer tree + // that originated the update, because the only identifying information + // we are logging about APZCs is the scroll id, and otherwise we could + // confuse APZCs from different layer trees with the same scroll id. + if (aLayersId == aState.mOriginatingLayersId) { + if (apzc->HasNoParentWithSameLayersId()) { + aState.mPaintLogger.LogTestData(aMetrics.GetScrollId(), + "hasNoParentWithSameLayersId", true); + } else { + MOZ_ASSERT(apzc->GetParent()); + aState.mPaintLogger.LogTestData(aMetrics.GetScrollId(), + "parentScrollId", + apzc->GetParent()->GetGuid().mScrollId); + } + if (aMetrics.IsRootContent()) { + aState.mPaintLogger.LogTestData(aMetrics.GetScrollId(), "isRootContent", + true); + } + // Note that the async scroll offset is in ParentLayer pixels + aState.mPaintLogger.LogTestData( + aMetrics.GetScrollId(), "asyncScrollOffset", + apzc->GetCurrentAsyncScrollOffset( + AsyncPanZoomController::eForHitTesting)); + aState.mPaintLogger.LogTestData(aMetrics.GetScrollId(), + "hasAsyncKeyScrolled", + apzc->TestHasAsyncKeyScrolled()); + } + + if (newApzc) { + auto it = mZoomConstraints.find(guid); + if (it != mZoomConstraints.end()) { + // We have a zoomconstraints for this guid, apply it. + apzc->UpdateZoomConstraints(it->second); + } else if (!apzc->HasNoParentWithSameLayersId()) { + // This is a sub-APZC, so inherit the zoom constraints from its parent. + // This ensures that if e.g. user-scalable=no was specified, none of the + // APZCs for that subtree allow double-tap to zoom. + apzc->UpdateZoomConstraints(apzc->GetParent()->GetZoomConstraints()); + } + // Otherwise, this is the root of a layers id, but we didn't have a saved + // zoom constraints. Leave it empty for now. + } + + // Add a guid -> APZC mapping for the newly created APZC. + insertResult.first->second.apzc = apzc; + } else { + // We already built an APZC earlier in this tree walk, but we have another + // layer now that will also be using that APZC. The hit-test region on the + // APZC needs to be updated to deal with the new layer's hit region. + + node = RecycleOrCreateNode(aProofOfTreeLock, aState, apzc, aLayersId); + AttachNodeToTree(node, aParent, aNextSibling); + + // Even though different layers associated with a given APZC may be at + // different levels in the layer tree (e.g. one being an uncle of another), + // we require from Layout that the CSS transforms up to their common + // ancestor be roughly the same. There are cases in which the transforms + // are not exactly the same, for example if the parent is container layer + // for an opacity, and this container layer has a resolution-induced scale + // as its base transform and a prescale that is supposed to undo that scale. + // Due to floating point inaccuracies those transforms can end up not quite + // canceling each other. That's why we're using a fuzzy comparison here + // instead of an exact one. + // In addition, two ancestor transforms are allowed to differ if one of + // them contains a perspective transform component and the other does not. + // This represents situations where some content in a scrollable frame + // is subject to a perspective transform and other content does not. + // In such cases, go with the one that does not include the perspective + // component; the perspective transform is remembered and applied to the + // children instead. + if (!aAncestorTransform.CombinedTransform().FuzzyEqualsMultiplicative( + apzc->GetAncestorTransform())) { + typedef TreeBuildingState::DeferredTransformMap::value_type PairType; + if (!aAncestorTransform.ContainsPerspectiveTransform() && + !apzc->AncestorTransformContainsPerspective()) { + NS_ASSERTION(false, + "Two layers that scroll together have different ancestor " + "transforms"); + } else if (!aAncestorTransform.ContainsPerspectiveTransform()) { + aState.mPerspectiveTransformsDeferredToChildren.insert( + PairType{apzc, apzc->GetAncestorTransformPerspective()}); + apzc->SetAncestorTransform(aAncestorTransform); + } else { + aState.mPerspectiveTransformsDeferredToChildren.insert( + PairType{apzc, aAncestorTransform.GetPerspectiveTransform()}); + } + } + + Maybe<ParentLayerIntRegion> clipRegion = + parentHasPerspective ? Nothing() : ComputeClipRegion(aLayersId, aLayer); + SetHitTestData(node, aLayer, clipRegion, aState.mOverrideFlags.top()); + } + + // Note: if layer properties must be propagated to nodes, RecvUpdate in + // LayerTransactionParent.cpp must ensure that APZ will be notified + // when those properties change. + node->SetScrollbarData(aLayer.GetScrollbarAnimationId(), + aLayer.GetScrollbarData()); + node->SetFixedPosData(aLayer.GetFixedPositionScrollContainerId(), + aLayer.GetFixedPositionSides(), + aLayer.GetFixedPositionAnimationId()); + node->SetStickyPosData(aLayer.GetStickyScrollContainerId(), + aLayer.GetStickyScrollRangeOuter(), + aLayer.GetStickyScrollRangeInner(), + aLayer.GetStickyPositionAnimationId()); + return node; +} + +template <typename PanGestureOrScrollWheelInput> +static bool WillHandleInput(const PanGestureOrScrollWheelInput& aPanInput) { + if (!XRE_IsParentProcess() || !NS_IsMainThread()) { + return true; + } + + WidgetWheelEvent wheelEvent = aPanInput.ToWidgetEvent(nullptr); + return APZInputBridge::ActionForWheelEvent(&wheelEvent).isSome(); +} + +/*static*/ +void APZCTreeManager::FlushApzRepaints(LayersId aLayersId) { + // Previously, paints were throttled and therefore this method was used to + // ensure any pending paints were flushed. Now, paints are flushed + // immediately, so it is safe to simply send a notification now. + APZCTM_LOG("Flushing repaints for layers id 0x%" PRIx64 "\n", + uint64_t(aLayersId)); + RefPtr<GeckoContentController> controller = GetContentController(aLayersId); +#ifndef MOZ_WIDGET_ANDROID + // On Android, this code is run in production and may actually get a nullptr + // controller here. On other platforms this code is test-only and should never + // get a nullptr. + MOZ_ASSERT(controller); +#endif + if (controller) { + controller->DispatchToRepaintThread(NewRunnableMethod( + "layers::GeckoContentController::NotifyFlushComplete", controller, + &GeckoContentController::NotifyFlushComplete)); + } +} + +void APZCTreeManager::MarkAsDetached(LayersId aLayersId) { + RecursiveMutexAutoLock lock(mTreeLock); + mDetachedLayersIds.insert(aLayersId); +} + +static bool HasNonLockModifier(Modifiers aModifiers) { + return (aModifiers & (MODIFIER_ALT | MODIFIER_ALTGRAPH | MODIFIER_CONTROL | + MODIFIER_FN | MODIFIER_META | MODIFIER_SHIFT | + MODIFIER_SYMBOL | MODIFIER_OS)) != 0; +} + +APZEventResult APZCTreeManager::ReceiveInputEvent(InputData& aEvent) { + APZThreadUtils::AssertOnControllerThread(); + APZEventResult result; + + // Use a RAII class for updating the focus sequence number of this event + AutoFocusSequenceNumberSetter focusSetter(mFocusState, aEvent); + + CompositorHitTestInfo hitResult = CompositorHitTestInvisibleToHit; + switch (aEvent.mInputType) { + case MULTITOUCH_INPUT: { + MultiTouchInput& touchInput = aEvent.AsMultiTouchInput(); + result = ProcessTouchInput(touchInput); + break; + } + case MOUSE_INPUT: { + MouseInput& mouseInput = aEvent.AsMouseInput(); + mouseInput.mHandledByAPZ = true; + + SetCurrentMousePosition(mouseInput.mOrigin); + + bool startsDrag = DragTracker::StartsDrag(mouseInput); + if (startsDrag) { + // If this is the start of a drag we need to unambiguously know if it's + // going to land on a scrollbar or not. We can't apply an untransform + // here without knowing that, so we need to ensure the untransform is + // a no-op. + FlushRepaintsToClearScreenToGeckoTransform(); + } + + HitTestResult hit = GetTargetAPZC(mouseInput.mOrigin); + aEvent.mLayersId = hit.mLayersId; + hitResult = hit.mHitResult; + bool hitScrollbar = (bool)hit.mScrollbarNode; + + // When the mouse is outside the window we still want to handle dragging + // but we won't find an APZC. Fallback to root APZC then. + { // scope lock + RecursiveMutexAutoLock lock(mTreeLock); + if (!hit.mTargetApzc && mRootNode) { + hit.mTargetApzc = mRootNode->GetApzc(); + } + } + + if (hit.mTargetApzc) { + if (StaticPrefs::apz_test_logging_enabled() && + mouseInput.mType == MouseInput::MOUSE_HITTEST) { + ScrollableLayerGuid guid = hit.mTargetApzc->GetGuid(); + + MutexAutoLock lock(mTestDataLock); + auto it = mTestData.find(guid.mLayersId); + MOZ_ASSERT(it != mTestData.end()); + it->second->RecordHitResult(mouseInput.mOrigin, hitResult, + guid.mLayersId, guid.mScrollId); + } + + TargetConfirmationFlags confFlags{hitResult}; + result.mStatus = mInputQueue->ReceiveInputEvent( + hit.mTargetApzc, confFlags, mouseInput, &result.mInputBlockId); + + // If we're starting an async scrollbar drag + bool apzDragEnabled = StaticPrefs::apz_drag_enabled(); + if (apzDragEnabled && startsDrag && hit.mScrollbarNode && + hit.mScrollbarNode->IsScrollThumbNode() && + hit.mScrollbarNode->GetScrollbarData().mThumbIsAsyncDraggable) { + SetupScrollbarDrag(mouseInput, hit.mScrollbarNode, + hit.mTargetApzc.get()); + } + + if (result.mStatus == nsEventStatus_eConsumeDoDefault) { + // This input event is part of a drag block, so whether or not it is + // directed at a scrollbar depends on whether the drag block started + // on a scrollbar. + hitScrollbar = mInputQueue->IsDragOnScrollbar(hitScrollbar); + } + + // Update the out-parameters so they are what the caller expects. + hit.mTargetApzc->GetGuid(&result.mTargetGuid); + result.mHandledResult = hit.HandledByRoot(); + + if (!hitScrollbar) { + // The input was not targeted at a scrollbar, so we untransform it + // like we do for other content. Scrollbars are "special" because they + // have special handling in AsyncCompositionManager when resolution is + // applied. TODO: we should find a better way to deal with this. + ScreenToParentLayerMatrix4x4 transformToApzc = + GetScreenToApzcTransform(hit.mTargetApzc); + ParentLayerToScreenMatrix4x4 transformToGecko = + GetApzcToGeckoTransform(hit.mTargetApzc); + ScreenToScreenMatrix4x4 outTransform = + transformToApzc * transformToGecko; + Maybe<ScreenPoint> untransformedRefPoint = + UntransformBy(outTransform, mouseInput.mOrigin); + if (untransformedRefPoint) { + mouseInput.mOrigin = *untransformedRefPoint; + } + } else { + // Likewise, if the input was targeted at a scrollbar, we don't want + // to apply the callback transform in the main thread, so we remove + // the scrollid from the guid. We need to keep the layersId intact so + // that the response from the child process doesn't get discarded. + result.mTargetGuid.mScrollId = ScrollableLayerGuid::NULL_SCROLL_ID; + } + } + break; + } + case SCROLLWHEEL_INPUT: { + FlushRepaintsToClearScreenToGeckoTransform(); + + // Do this before early return for Fission hit testing. + ScrollWheelInput& wheelInput = aEvent.AsScrollWheelInput(); + HitTestResult hit = GetTargetAPZC(wheelInput.mOrigin); + aEvent.mLayersId = hit.mLayersId; + hitResult = hit.mHitResult; + + wheelInput.mHandledByAPZ = WillHandleInput(wheelInput); + if (!wheelInput.mHandledByAPZ) { + return result; + } + + mOvershootDetector.Update(wheelInput); + + if (hit.mTargetApzc) { + MOZ_ASSERT(hitResult != CompositorHitTestInvisibleToHit); + + if (wheelInput.mAPZAction == APZWheelAction::PinchZoom) { + // The mousewheel may have hit a subframe, but we want to send the + // pinch-zoom events to the root-content APZC. + { + RecursiveMutexAutoLock lock(mTreeLock); + hit.mTargetApzc = + FindRootContentApzcForLayersId(hit.mTargetApzc->GetLayersId()); + } + if (hit.mTargetApzc) { + SynthesizePinchGestureFromMouseWheel(wheelInput, hit.mTargetApzc); + } + result.mStatus = nsEventStatus_eConsumeNoDefault; + return result; + } + + MOZ_ASSERT(wheelInput.mAPZAction == APZWheelAction::Scroll); + + // For wheel events, the call to ReceiveInputEvent below may result in + // scrolling, which changes the async transform. However, the event we + // want to pass to gecko should be the pre-scroll event coordinates, + // transformed into the gecko space. (pre-scroll because the mouse + // cursor is stationary during wheel scrolling, unlike touchmove + // events). Since we just flushed the pending repaints the transform to + // gecko space should only consist of overscroll-cancelling transforms. + ScreenToScreenMatrix4x4 transformToGecko = + GetScreenToApzcTransform(hit.mTargetApzc) * + GetApzcToGeckoTransform(hit.mTargetApzc); + Maybe<ScreenPoint> untransformedOrigin = + UntransformBy(transformToGecko, wheelInput.mOrigin); + + if (!untransformedOrigin) { + return result; + } + + result.mStatus = mInputQueue->ReceiveInputEvent( + hit.mTargetApzc, TargetConfirmationFlags{hitResult}, wheelInput, + &result.mInputBlockId); + + // Update the out-parameters so they are what the caller expects. + hit.mTargetApzc->GetGuid(&result.mTargetGuid); + result.mHandledResult = hit.HandledByRoot(); + wheelInput.mOrigin = *untransformedOrigin; + } + break; + } + case PANGESTURE_INPUT: { + FlushRepaintsToClearScreenToGeckoTransform(); + + // Do this before early return for Fission hit testing. + PanGestureInput& panInput = aEvent.AsPanGestureInput(); + HitTestResult hit = GetTargetAPZC(panInput.mPanStartPoint); + aEvent.mLayersId = hit.mLayersId; + hitResult = hit.mHitResult; + + panInput.mHandledByAPZ = WillHandleInput(panInput); + if (!panInput.mHandledByAPZ) { + return result; + } + + // If/when we enable support for pan inputs off-main-thread, we'll need + // to duplicate this EventStateManager code or something. See the call to + // GetUserPrefsForWheelEvent in IAPZCTreeManager.cpp for why these fields + // are stored separately. + MOZ_ASSERT(NS_IsMainThread()); + WidgetWheelEvent wheelEvent = panInput.ToWidgetEvent(nullptr); + EventStateManager::GetUserPrefsForWheelEvent( + &wheelEvent, &panInput.mUserDeltaMultiplierX, + &panInput.mUserDeltaMultiplierY); + + if (hit.mTargetApzc) { + MOZ_ASSERT(hitResult != CompositorHitTestInvisibleToHit); + + // For pan gesture events, the call to ReceiveInputEvent below may + // result in scrolling, which changes the async transform. However, the + // event we want to pass to gecko should be the pre-scroll event + // coordinates, transformed into the gecko space. (pre-scroll because + // the mouse cursor is stationary during pan gesture scrolling, unlike + // touchmove events). Since we just flushed the pending repaints the + // transform to gecko space should only consist of overscroll-cancelling + // transforms. + ScreenToScreenMatrix4x4 transformToGecko = + GetScreenToApzcTransform(hit.mTargetApzc) * + GetApzcToGeckoTransform(hit.mTargetApzc); + Maybe<ScreenPoint> untransformedStartPoint = + UntransformBy(transformToGecko, panInput.mPanStartPoint); + Maybe<ScreenPoint> untransformedDisplacement = + UntransformVector(transformToGecko, panInput.mPanDisplacement, + panInput.mPanStartPoint); + + if (!untransformedStartPoint || !untransformedDisplacement) { + return result; + } + + result.mStatus = mInputQueue->ReceiveInputEvent( + hit.mTargetApzc, TargetConfirmationFlags{hitResult}, panInput, + &result.mInputBlockId); + + // Update the out-parameters so they are what the caller expects. + hit.mTargetApzc->GetGuid(&result.mTargetGuid); + result.mHandledResult = hit.HandledByRoot(); + panInput.mPanStartPoint = *untransformedStartPoint; + panInput.mPanDisplacement = *untransformedDisplacement; + + panInput.mOverscrollBehaviorAllowsSwipe = + hit.mTargetApzc->OverscrollBehaviorAllowsSwipe(); + } + break; + } + case PINCHGESTURE_INPUT: { + PinchGestureInput& pinchInput = aEvent.AsPinchGestureInput(); + if (HasNonLockModifier(pinchInput.modifiers)) { + APZCTM_LOG("Discarding pinch input due to modifiers 0x%x\n", + pinchInput.modifiers); + return result; + } + + HitTestResult hit = GetTargetAPZC(pinchInput.mFocusPoint); + aEvent.mLayersId = hit.mLayersId; + hitResult = hit.mHitResult; + + // We always handle pinch gestures as pinch zooms. + pinchInput.mHandledByAPZ = true; + + if (hit.mTargetApzc) { + MOZ_ASSERT(hitResult != CompositorHitTestInvisibleToHit); + + if (!hit.mTargetApzc->IsRootContent()) { + hit.mTargetApzc = FindZoomableApzc(hit.mTargetApzc); + } + } + + if (hit.mTargetApzc) { + ScreenToScreenMatrix4x4 outTransform = + GetScreenToApzcTransform(hit.mTargetApzc) * + GetApzcToGeckoTransform(hit.mTargetApzc); + Maybe<ScreenPoint> untransformedFocusPoint = + UntransformBy(outTransform, pinchInput.mFocusPoint); + + if (!untransformedFocusPoint) { + return result; + } + + result.mStatus = mInputQueue->ReceiveInputEvent( + hit.mTargetApzc, TargetConfirmationFlags{hitResult}, pinchInput, + &result.mInputBlockId); + + // Update the out-parameters so they are what the caller expects. + hit.mTargetApzc->GetGuid(&result.mTargetGuid); + result.mHandledResult = hit.HandledByRoot(); + pinchInput.mFocusPoint = *untransformedFocusPoint; + } + break; + } + case TAPGESTURE_INPUT: { // note: no one currently sends these + TapGestureInput& tapInput = aEvent.AsTapGestureInput(); + HitTestResult hit = GetTargetAPZC(tapInput.mPoint); + aEvent.mLayersId = hit.mLayersId; + hitResult = hit.mHitResult; + + if (hit.mTargetApzc) { + MOZ_ASSERT(hitResult != CompositorHitTestInvisibleToHit); + + ScreenToScreenMatrix4x4 outTransform = + GetScreenToApzcTransform(hit.mTargetApzc) * + GetApzcToGeckoTransform(hit.mTargetApzc); + Maybe<ScreenIntPoint> untransformedPoint = + UntransformBy(outTransform, tapInput.mPoint); + + if (!untransformedPoint) { + return result; + } + + result.mStatus = mInputQueue->ReceiveInputEvent( + hit.mTargetApzc, TargetConfirmationFlags{hitResult}, tapInput, + &result.mInputBlockId); + + // Update the out-parameters so they are what the caller expects. + hit.mTargetApzc->GetGuid(&result.mTargetGuid); + result.mHandledResult = hit.HandledByRoot(); + tapInput.mPoint = *untransformedPoint; + } + break; + } + case KEYBOARD_INPUT: { + // Disable async keyboard scrolling when accessibility.browsewithcaret is + // enabled + if (!StaticPrefs::apz_keyboard_enabled_AtStartup() || + StaticPrefs::accessibility_browsewithcaret()) { + APZ_KEY_LOG("Skipping key input from invalid prefs\n"); + return result; + } + + KeyboardInput& keyInput = aEvent.AsKeyboardInput(); + + // Try and find a matching shortcut for this keyboard input + Maybe<KeyboardShortcut> shortcut = mKeyboardMap.FindMatch(keyInput); + + if (!shortcut) { + APZ_KEY_LOG("Skipping key input with no shortcut\n"); + + // If we don't have a shortcut for this key event, then we can keep our + // focus only if we know there are no key event listeners for this + // target + if (mFocusState.CanIgnoreKeyboardShortcutMisses()) { + focusSetter.MarkAsNonFocusChanging(); + } + return result; + } + + // Check if this shortcut needs to be dispatched to content. Anything + // matching this is assumed to be able to change focus. + if (shortcut->mDispatchToContent) { + APZ_KEY_LOG("Skipping key input with dispatch-to-content shortcut\n"); + return result; + } + + // We know we have an action to execute on whatever is the current focus + // target + const KeyboardScrollAction& action = shortcut->mAction; + + // The current focus target depends on which direction the scroll is to + // happen + Maybe<ScrollableLayerGuid> targetGuid; + switch (action.mType) { + case KeyboardScrollAction::eScrollCharacter: { + targetGuid = mFocusState.GetHorizontalTarget(); + break; + } + case KeyboardScrollAction::eScrollLine: + case KeyboardScrollAction::eScrollPage: + case KeyboardScrollAction::eScrollComplete: { + targetGuid = mFocusState.GetVerticalTarget(); + break; + } + } + + // If we don't have a scroll target then either we have a stale focus + // target, the focused element has event listeners, or the focused element + // doesn't have a layerized scroll frame. In any case we need to dispatch + // to content. + if (!targetGuid) { + APZ_KEY_LOG("Skipping key input with no current focus target\n"); + return result; + } + + RefPtr<AsyncPanZoomController> targetApzc = + GetTargetAPZC(targetGuid->mLayersId, targetGuid->mScrollId); + + if (!targetApzc) { + APZ_KEY_LOG("Skipping key input with focus target but no APZC\n"); + return result; + } + + // Attach the keyboard scroll action to the input event for processing + // by the input queue. + keyInput.mAction = action; + + APZ_KEY_LOG("Dispatching key input with apzc=%p\n", targetApzc.get()); + + // Dispatch the event to the input queue. + result.mStatus = mInputQueue->ReceiveInputEvent( + targetApzc, TargetConfirmationFlags{true}, keyInput, + &result.mInputBlockId); + + // Any keyboard event that is dispatched to the input queue at this point + // should have been consumed + MOZ_ASSERT(result.mStatus == nsEventStatus_eConsumeDoDefault || + result.mStatus == nsEventStatus_eConsumeNoDefault); + + keyInput.mHandledByAPZ = true; + focusSetter.MarkAsNonFocusChanging(); + + break; + } + } + return result; +} + +static TouchBehaviorFlags ConvertToTouchBehavior( + const CompositorHitTestInfo& info) { + TouchBehaviorFlags result = AllowedTouchBehavior::UNKNOWN; + if (info == CompositorHitTestInvisibleToHit) { + result = AllowedTouchBehavior::NONE; + } else if (info.contains(CompositorHitTestFlags::eIrregularArea)) { + // Note that eApzAwareListeners and eInactiveScrollframe are similar + // to eIrregularArea in some respects, but are not relevant for the + // purposes of this function, which deals specifically with touch-action. + result = AllowedTouchBehavior::UNKNOWN; + } else { + result = AllowedTouchBehavior::VERTICAL_PAN | + AllowedTouchBehavior::HORIZONTAL_PAN | + AllowedTouchBehavior::PINCH_ZOOM | + AllowedTouchBehavior::DOUBLE_TAP_ZOOM; + if (info.contains(CompositorHitTestFlags::eTouchActionPanXDisabled)) { + result &= ~AllowedTouchBehavior::HORIZONTAL_PAN; + } + if (info.contains(CompositorHitTestFlags::eTouchActionPanYDisabled)) { + result &= ~AllowedTouchBehavior::VERTICAL_PAN; + } + if (info.contains(CompositorHitTestFlags::eTouchActionPinchZoomDisabled)) { + result &= ~AllowedTouchBehavior::PINCH_ZOOM; + } + if (info.contains( + CompositorHitTestFlags::eTouchActionDoubleTapZoomDisabled)) { + result &= ~AllowedTouchBehavior::DOUBLE_TAP_ZOOM; + } + } + return result; +} + +APZCTreeManager::HitTestResult APZCTreeManager::GetTouchInputBlockAPZC( + const MultiTouchInput& aEvent, + nsTArray<TouchBehaviorFlags>* aOutTouchBehaviors) { + HitTestResult hit; + if (aEvent.mTouches.Length() == 0) { + return hit; + } + + FlushRepaintsToClearScreenToGeckoTransform(); + + hit = GetTargetAPZC(aEvent.mTouches[0].mScreenPoint); + // Don't set a layers id on multi-touch events. + if (aEvent.mTouches.Length() != 1) { + hit.mLayersId = LayersId{0}; + } + + if (aOutTouchBehaviors) { + aOutTouchBehaviors->AppendElement(ConvertToTouchBehavior(hit.mHitResult)); + } + for (size_t i = 1; i < aEvent.mTouches.Length(); i++) { + HitTestResult hit2 = GetTargetAPZC(aEvent.mTouches[i].mScreenPoint); + if (aOutTouchBehaviors) { + aOutTouchBehaviors->AppendElement( + ConvertToTouchBehavior(hit2.mHitResult)); + } + hit.mTargetApzc = GetZoomableTarget(hit.mTargetApzc, hit2.mTargetApzc); + APZCTM_LOG("Using APZC %p as the root APZC for multi-touch\n", + hit.mTargetApzc.get()); + // A multi-touch gesture will not be a scrollbar drag, even if the + // first touch point happened to hit a scrollbar. + hit.mScrollbarNode.Clear(); + + // XXX we should probably be combining the hit results from the different + // touch points somehow, instead of just using the last one. + hit.mHitResult = hit2.mHitResult; + } + + return hit; +} + +APZEventResult APZCTreeManager::ProcessTouchInput(MultiTouchInput& aInput) { + APZEventResult result; // mStatus == eIgnore + aInput.mHandledByAPZ = true; + nsTArray<TouchBehaviorFlags> touchBehaviors; + HitTestingTreeNodeAutoLock hitScrollbarNode; + if (aInput.mType == MultiTouchInput::MULTITOUCH_START) { + // If we are panned into overscroll and a second finger goes down, + // ignore that second touch point completely. The touch-start for it is + // dropped completely; subsequent touch events until the touch-end for it + // will have this touch point filtered out. + // (By contrast, if we're in overscroll but not panning, such as after + // putting two fingers down during an overscroll animation, we process the + // second touch and proceed to pinch.) + if (mTouchBlockHitResult.mTargetApzc && + mTouchBlockHitResult.mTargetApzc->IsInPanningState() && + BuildOverscrollHandoffChain(mTouchBlockHitResult.mTargetApzc) + ->HasOverscrolledApzc()) { + if (mRetainedTouchIdentifier == -1) { + mRetainedTouchIdentifier = + mTouchBlockHitResult.mTargetApzc->GetLastTouchIdentifier(); + } + result.mStatus = nsEventStatus_eConsumeNoDefault; + return result; + } + + HitTestResult hit = GetTouchInputBlockAPZC(aInput, &touchBehaviors); + // Repopulate mTouchBlockHitResult with the fields we care about. + mTouchBlockHitResult = HitTestResult(); + mTouchBlockHitResult.mTargetApzc = hit.mTargetApzc; + mTouchBlockHitResult.mHitResult = hit.mHitResult; + mTouchBlockHitResult.mFixedPosSides = hit.mFixedPosSides; + if (hit.mLayersId.IsValid()) { + // Check for validity because we won't get a layers id for multi-touch + // events. + aInput.mLayersId = hit.mLayersId; + } + hitScrollbarNode = std::move(hit.mScrollbarNode); + + // Check if this event starts a scrollbar touch-drag. The conditions + // checked are similar to the ones we check for MOUSE_INPUT starting + // a scrollbar mouse-drag. + mInScrollbarTouchDrag = + StaticPrefs::apz_drag_enabled() && + StaticPrefs::apz_drag_touch_enabled() && hitScrollbarNode && + hitScrollbarNode->IsScrollThumbNode() && + hitScrollbarNode->GetScrollbarData().mThumbIsAsyncDraggable; + + MOZ_ASSERT(touchBehaviors.Length() == aInput.mTouches.Length()); + for (size_t i = 0; i < touchBehaviors.Length(); i++) { + APZCTM_LOG("Touch point has allowed behaviours 0x%02x\n", + touchBehaviors[i]); + if (touchBehaviors[i] == AllowedTouchBehavior::UNKNOWN) { + // If there's any unknown items in the list, throw it out and we'll + // wait for the main thread to send us a notification. + touchBehaviors.Clear(); + break; + } + } + } else if (mTouchBlockHitResult.mTargetApzc) { + APZCTM_LOG("Re-using APZC %p as continuation of event block\n", + mTouchBlockHitResult.mTargetApzc.get()); + } + + if (mInScrollbarTouchDrag) { + result = ProcessTouchInputForScrollbarDrag(aInput, hitScrollbarNode, + mTouchBlockHitResult.mHitResult); + } else { + // If we receive a touch-cancel, it means all touches are finished, so we + // can stop ignoring any that we were ignoring. + if (aInput.mType == MultiTouchInput::MULTITOUCH_CANCEL) { + mRetainedTouchIdentifier = -1; + } + + // If we are currently ignoring any touch points, filter them out from the + // set of touch points included in this event. Note that we modify aInput + // itself, so that the touch points are also filtered out when the caller + // passes the event on to content. + if (mRetainedTouchIdentifier != -1) { + for (size_t j = 0; j < aInput.mTouches.Length(); ++j) { + if (aInput.mTouches[j].mIdentifier != mRetainedTouchIdentifier) { + aInput.mTouches.RemoveElementAt(j); + if (!touchBehaviors.IsEmpty()) { + MOZ_ASSERT(touchBehaviors.Length() > j); + touchBehaviors.RemoveElementAt(j); + } + --j; + } + } + if (aInput.mTouches.IsEmpty()) { + result.mStatus = nsEventStatus_eConsumeNoDefault; + return result; + } + } + + if (mTouchBlockHitResult.mTargetApzc) { + MOZ_ASSERT(mTouchBlockHitResult.mHitResult != + CompositorHitTestInvisibleToHit); + + mTouchBlockHitResult.mTargetApzc->GetGuid(&result.mTargetGuid); + result.mHandledResult = mTouchBlockHitResult.HandledByRoot(); + result.mStatus = mInputQueue->ReceiveInputEvent( + mTouchBlockHitResult.mTargetApzc, + TargetConfirmationFlags{mTouchBlockHitResult.mHitResult}, aInput, + &result.mInputBlockId, &result.mHandledResult, + touchBehaviors.IsEmpty() ? Nothing() + : Some(std::move(touchBehaviors))); + + // For computing the event to pass back to Gecko, use up-to-date + // transforms (i.e. not anything cached in an input block). This ensures + // that transformToApzc and transformToGecko are in sync. + // Note: we are not using ConvertToGecko() here, because we don't + // want to multiply transformToApzc and transformToGecko once + // for each touch point. + ScreenToParentLayerMatrix4x4 transformToApzc = + GetScreenToApzcTransform(mTouchBlockHitResult.mTargetApzc); + ParentLayerToScreenMatrix4x4 transformToGecko = + GetApzcToGeckoTransform(mTouchBlockHitResult.mTargetApzc); + ScreenToScreenMatrix4x4 outTransform = transformToApzc * transformToGecko; + + for (size_t i = 0; i < aInput.mTouches.Length(); i++) { + SingleTouchData& touchData = aInput.mTouches[i]; + Maybe<ScreenIntPoint> untransformedScreenPoint = + UntransformBy(outTransform, touchData.mScreenPoint); + if (!untransformedScreenPoint) { + result.mStatus = nsEventStatus_eIgnore; + return result; + } + touchData.mScreenPoint = *untransformedScreenPoint; + if (mTouchBlockHitResult.mFixedPosSides != SideBits::eNone) { + MutexAutoLock lock(mMapLock); + touchData.mScreenPoint -= RoundedToInt(apz::ComputeFixedMarginsOffset( + GetCompositorFixedLayerMargins(lock), + mTouchBlockHitResult.mFixedPosSides, mGeckoFixedLayerMargins)); + } + } + } + } + + mTouchCounter.Update(aInput); + + // If it's the end of the touch sequence then clear out variables so we + // don't keep dangling references and leak things. + if (mTouchCounter.GetActiveTouchCount() == 0) { + mTouchBlockHitResult = HitTestResult(); + mRetainedTouchIdentifier = -1; + mInScrollbarTouchDrag = false; + } + + return result; +} + +static MouseInput::MouseType MultiTouchTypeToMouseType( + MultiTouchInput::MultiTouchType aType) { + switch (aType) { + case MultiTouchInput::MULTITOUCH_START: + return MouseInput::MOUSE_DOWN; + case MultiTouchInput::MULTITOUCH_MOVE: + return MouseInput::MOUSE_MOVE; + case MultiTouchInput::MULTITOUCH_END: + case MultiTouchInput::MULTITOUCH_CANCEL: + return MouseInput::MOUSE_UP; + } + MOZ_ASSERT_UNREACHABLE("Invalid multi-touch type"); + return MouseInput::MOUSE_NONE; +} + +APZEventResult APZCTreeManager::ProcessTouchInputForScrollbarDrag( + MultiTouchInput& aTouchInput, + const HitTestingTreeNodeAutoLock& aScrollThumbNode, + const gfx::CompositorHitTestInfo& aHitInfo) { + MOZ_ASSERT(mRetainedTouchIdentifier == -1); + MOZ_ASSERT(mTouchBlockHitResult.mTargetApzc); + MOZ_ASSERT(aTouchInput.mTouches.Length() == 1); + + // Synthesize a mouse event based on the touch event, so that we can + // reuse code in InputQueue and APZC for handling scrollbar mouse-drags. + MouseInput mouseInput{MultiTouchTypeToMouseType(aTouchInput.mType), + MouseInput::PRIMARY_BUTTON, + dom::MouseEvent_Binding::MOZ_SOURCE_TOUCH, + MouseButtonsFlag::ePrimaryFlag, + aTouchInput.mTouches[0].mScreenPoint, + aTouchInput.mTime, + aTouchInput.mTimeStamp, + aTouchInput.modifiers}; + mouseInput.mHandledByAPZ = true; + + TargetConfirmationFlags targetConfirmed{aHitInfo}; + APZEventResult result; + result.mStatus = mInputQueue->ReceiveInputEvent( + mTouchBlockHitResult.mTargetApzc, targetConfirmed, mouseInput, + &result.mInputBlockId); + + // |aScrollThumbNode| is non-null iff. this is the event that starts the drag. + // If so, set up the drag. + if (aScrollThumbNode) { + SetupScrollbarDrag(mouseInput, aScrollThumbNode, + mTouchBlockHitResult.mTargetApzc.get()); + } + + mTouchBlockHitResult.mTargetApzc->GetGuid(&result.mTargetGuid); + result.mHandledResult = mTouchBlockHitResult.HandledByRoot(); + + // Since the input was targeted at a scrollbar: + // - The original touch event (which will be sent on to content) will + // not be untransformed. + // - We don't want to apply the callback transform in the main thread, + // so we remove the scrollid from the guid. + // Both of these match the behaviour of mouse events that target a scrollbar; + // see the code for handling mouse events in ReceiveInputEvent() for + // additional explanation. + result.mTargetGuid.mScrollId = ScrollableLayerGuid::NULL_SCROLL_ID; + + return result; +} + +void APZCTreeManager::SetupScrollbarDrag( + MouseInput& aMouseInput, const HitTestingTreeNodeAutoLock& aScrollThumbNode, + AsyncPanZoomController* aApzc) { + DragBlockState* dragBlock = mInputQueue->GetCurrentDragBlock(); + if (!dragBlock) { + return; + } + + const ScrollbarData& thumbData = aScrollThumbNode->GetScrollbarData(); + MOZ_ASSERT(thumbData.mDirection.isSome()); + + // Record the thumb's position at the start of the drag. + // We snap back to this position if, during the drag, the mouse + // gets sufficiently far away from the scrollbar. + dragBlock->SetInitialThumbPos(thumbData.mThumbStart); + + // Under some conditions, we can confirm the drag block right away. + // Otherwise, we have to wait for a main-thread confirmation. + if (StaticPrefs::apz_drag_initial_enabled() && + // check that the scrollbar's target scroll frame is layerized + aScrollThumbNode->GetScrollTargetId() == aApzc->GetGuid().mScrollId && + !aApzc->IsScrollInfoLayer()) { + uint64_t dragBlockId = dragBlock->GetBlockId(); + // AsyncPanZoomController::HandleInputEvent() will call + // TransformToLocal() on the event, but we need its mLocalOrigin now + // to compute a drag start offset for the AsyncDragMetrics. + aMouseInput.TransformToLocal(aApzc->GetTransformToThis()); + CSSCoord dragStart = + aApzc->ConvertScrollbarPoint(aMouseInput.mLocalOrigin, thumbData); + // ConvertScrollbarPoint() got the drag start offset relative to + // the scroll track. Now get it relative to the thumb. + // ScrollThumbData::mThumbStart stores the offset of the thumb + // relative to the scroll track at the time of the last paint. + // Since that paint, the thumb may have acquired an async transform + // due to async scrolling, so look that up and apply it. + LayerToParentLayerMatrix4x4 thumbTransform; + { + RecursiveMutexAutoLock lock(mTreeLock); + thumbTransform = ComputeTransformForNode(aScrollThumbNode.Get(lock)); + } + // Only consider the translation, since we do not support both + // zooming and scrollbar dragging on any platform. + CSSCoord thumbStart = + thumbData.mThumbStart + + ((*thumbData.mDirection == ScrollDirection::eHorizontal) + ? thumbTransform._41 + : thumbTransform._42); + dragStart -= thumbStart; + + // Content can't prevent scrollbar dragging with preventDefault(), + // so we don't need to wait for a content response. It's important + // to do this before calling ConfirmDragBlock() since that can + // potentially process and consume the block. + dragBlock->SetContentResponse(false); + + NotifyScrollbarDragInitiated(dragBlockId, aApzc->GetGuid(), + *thumbData.mDirection); + + mInputQueue->ConfirmDragBlock( + dragBlockId, aApzc, + AsyncDragMetrics(aApzc->GetGuid().mScrollId, + aApzc->GetGuid().mPresShellId, dragBlockId, dragStart, + *thumbData.mDirection)); + } +} + +void APZCTreeManager::SynthesizePinchGestureFromMouseWheel( + const ScrollWheelInput& aWheelInput, + const RefPtr<AsyncPanZoomController>& aTarget) { + MOZ_ASSERT(aTarget); + + ScreenPoint focusPoint = aWheelInput.mOrigin; + + // Compute span values based on the wheel delta. + ScreenCoord oldSpan = 100; + ScreenCoord newSpan = oldSpan + aWheelInput.mDeltaY; + + // There's no ambiguity as to the target for pinch gesture events. + TargetConfirmationFlags confFlags{true}; + + PinchGestureInput pinchStart{PinchGestureInput::PINCHGESTURE_START, + PinchGestureInput::MOUSEWHEEL, + aWheelInput.mTime, + aWheelInput.mTimeStamp, + ExternalPoint(0, 0), + focusPoint, + oldSpan, + oldSpan, + aWheelInput.modifiers}; + PinchGestureInput pinchScale1{PinchGestureInput::PINCHGESTURE_SCALE, + PinchGestureInput::MOUSEWHEEL, + aWheelInput.mTime, + aWheelInput.mTimeStamp, + ExternalPoint(0, 0), + focusPoint, + oldSpan, + oldSpan, + aWheelInput.modifiers}; + PinchGestureInput pinchScale2{PinchGestureInput::PINCHGESTURE_SCALE, + PinchGestureInput::MOUSEWHEEL, + aWheelInput.mTime, + aWheelInput.mTimeStamp, + ExternalPoint(0, 0), + focusPoint, + oldSpan, + newSpan, + aWheelInput.modifiers}; + PinchGestureInput pinchEnd{PinchGestureInput::PINCHGESTURE_END, + PinchGestureInput::MOUSEWHEEL, + aWheelInput.mTime, + aWheelInput.mTimeStamp, + ExternalPoint(0, 0), + focusPoint, + newSpan, + newSpan, + aWheelInput.modifiers}; + + mInputQueue->ReceiveInputEvent(aTarget, confFlags, pinchStart, nullptr); + mInputQueue->ReceiveInputEvent(aTarget, confFlags, pinchScale1, nullptr); + mInputQueue->ReceiveInputEvent(aTarget, confFlags, pinchScale2, nullptr); + mInputQueue->ReceiveInputEvent(aTarget, confFlags, pinchEnd, nullptr); +} + +void APZCTreeManager::UpdateWheelTransaction(LayoutDeviceIntPoint aRefPoint, + EventMessage aEventMessage) { + APZThreadUtils::AssertOnControllerThread(); + + WheelBlockState* txn = mInputQueue->GetActiveWheelTransaction(); + if (!txn) { + return; + } + + // If the transaction has simply timed out, we don't need to do anything + // else. + if (txn->MaybeTimeout(TimeStamp::Now())) { + return; + } + + switch (aEventMessage) { + case eMouseMove: + case eDragOver: { + ScreenIntPoint point = ViewAs<ScreenPixel>( + aRefPoint, + PixelCastJustification::LayoutDeviceIsScreenForUntransformedEvent); + + txn->OnMouseMove(point); + + return; + } + case eKeyPress: + case eKeyUp: + case eKeyDown: + case eMouseUp: + case eMouseDown: + case eMouseDoubleClick: + case eMouseAuxClick: + case eMouseClick: + case eContextMenu: + case eDrop: + txn->EndTransaction(); + return; + default: + break; + } +} + +void APZCTreeManager::ProcessUnhandledEvent(LayoutDeviceIntPoint* aRefPoint, + ScrollableLayerGuid* aOutTargetGuid, + uint64_t* aOutFocusSequenceNumber, + LayersId* aOutLayersId) { + APZThreadUtils::AssertOnControllerThread(); + + // Transform the aRefPoint. + // If the event hits an overscrolled APZC, instruct the caller to ignore it. + PixelCastJustification LDIsScreen = + PixelCastJustification::LayoutDeviceIsScreenForUntransformedEvent; + ScreenIntPoint refPointAsScreen = ViewAs<ScreenPixel>(*aRefPoint, LDIsScreen); + HitTestResult hit = GetTargetAPZC(refPointAsScreen); + if (aOutLayersId) { + *aOutLayersId = hit.mLayersId; + } + if (hit.mTargetApzc) { + MOZ_ASSERT(hit.mHitResult != CompositorHitTestInvisibleToHit); + hit.mTargetApzc->GetGuid(aOutTargetGuid); + ScreenToParentLayerMatrix4x4 transformToApzc = + GetScreenToApzcTransform(hit.mTargetApzc); + ParentLayerToScreenMatrix4x4 transformToGecko = + GetApzcToGeckoTransform(hit.mTargetApzc); + ScreenToScreenMatrix4x4 outTransform = transformToApzc * transformToGecko; + Maybe<ScreenIntPoint> untransformedRefPoint = + UntransformBy(outTransform, refPointAsScreen); + if (untransformedRefPoint) { + *aRefPoint = + ViewAs<LayoutDevicePixel>(*untransformedRefPoint, LDIsScreen); + } + } + + // Update the focus sequence number and attach it to the event + mFocusState.ReceiveFocusChangingEvent(); + *aOutFocusSequenceNumber = mFocusState.LastAPZProcessedEvent(); +} + +void APZCTreeManager::SetKeyboardMap(const KeyboardMap& aKeyboardMap) { + APZThreadUtils::AssertOnControllerThread(); + + mKeyboardMap = aKeyboardMap; +} + +void APZCTreeManager::ZoomToRect(const ScrollableLayerGuid& aGuid, + const CSSRect& aRect, const uint32_t aFlags) { + // We could probably move this to run on the updater thread if needed, but + // either way we should restrict it to a single thread. For now let's use the + // controller thread. + APZThreadUtils::AssertOnControllerThread(); + + RefPtr<AsyncPanZoomController> apzc = GetTargetAPZC(aGuid); + if (apzc) { + apzc->ZoomToRect(aRect, aFlags); + } +} + +void APZCTreeManager::ContentReceivedInputBlock(uint64_t aInputBlockId, + bool aPreventDefault) { + APZThreadUtils::AssertOnControllerThread(); + + mInputQueue->ContentReceivedInputBlock(aInputBlockId, aPreventDefault); +} + +void APZCTreeManager::SetTargetAPZC( + uint64_t aInputBlockId, const nsTArray<ScrollableLayerGuid>& aTargets) { + APZThreadUtils::AssertOnControllerThread(); + + RefPtr<AsyncPanZoomController> target = nullptr; + if (aTargets.Length() > 0) { + target = GetTargetAPZC(aTargets[0]); + } + for (size_t i = 1; i < aTargets.Length(); i++) { + RefPtr<AsyncPanZoomController> apzc = GetTargetAPZC(aTargets[i]); + target = GetZoomableTarget(target, apzc); + } + if (InputBlockState* block = mInputQueue->GetBlockForId(aInputBlockId)) { + if (block->AsPinchGestureBlock() && aTargets.Length() == 1) { + target = FindZoomableApzc(target); + } + } + mInputQueue->SetConfirmedTargetApzc(aInputBlockId, target); +} + +void APZCTreeManager::UpdateZoomConstraints( + const ScrollableLayerGuid& aGuid, + const Maybe<ZoomConstraints>& aConstraints) { + if (!GetUpdater()->IsUpdaterThread()) { + // This can happen if we're in the UI process and got a call directly from + // nsBaseWidget or from a content process over PAPZCTreeManager. In that + // case we get this call on the compositor thread, which may be different + // from the updater thread. It can also happen in the GPU process if that is + // enabled, since the call will go over PAPZCTreeManager and arrive on the + // compositor thread in the GPU process. + GetUpdater()->RunOnUpdaterThread( + aGuid.mLayersId, + NewRunnableMethod<ScrollableLayerGuid, Maybe<ZoomConstraints>>( + "APZCTreeManager::UpdateZoomConstraints", this, + &APZCTreeManager::UpdateZoomConstraints, aGuid, aConstraints)); + return; + } + + AssertOnUpdaterThread(); + + RecursiveMutexAutoLock lock(mTreeLock); + RefPtr<HitTestingTreeNode> node = GetTargetNode(aGuid, nullptr); + MOZ_ASSERT(!node || node->GetApzc()); // any node returned must have an APZC + + // Propagate the zoom constraints down to the subtree, stopping at APZCs + // which have their own zoom constraints or are in a different layers id. + if (aConstraints) { + APZCTM_LOG("Recording constraints %s for guid %s\n", + ToString(aConstraints.value()).c_str(), ToString(aGuid).c_str()); + mZoomConstraints[aGuid] = aConstraints.ref(); + } else { + APZCTM_LOG("Removing constraints for guid %s\n", ToString(aGuid).c_str()); + mZoomConstraints.erase(aGuid); + } + if (node && aConstraints) { + ForEachNode<ReverseIterator>( + node.get(), [&aConstraints, &node, this](HitTestingTreeNode* aNode) { + if (aNode != node) { + if (AsyncPanZoomController* childApzc = aNode->GetApzc()) { + // We can have subtrees with their own zoom constraints or + // separate layers id - leave these alone. + if (childApzc->HasNoParentWithSameLayersId() || + this->mZoomConstraints.find(childApzc->GetGuid()) != + this->mZoomConstraints.end()) { + return TraversalFlag::Skip; + } + } + } + if (aNode->IsPrimaryHolder()) { + MOZ_ASSERT(aNode->GetApzc()); + aNode->GetApzc()->UpdateZoomConstraints(aConstraints.ref()); + } + return TraversalFlag::Continue; + }); + } +} + +void APZCTreeManager::FlushRepaintsToClearScreenToGeckoTransform() { + // As the name implies, we flush repaint requests for the entire APZ tree in + // order to clear the screen-to-gecko transform (aka the "untransform" applied + // to incoming input events before they can be passed on to Gecko). + // + // The primary reason we do this is to avoid the problem where input events, + // after being untransformed, end up hit-testing differently in Gecko. This + // might happen in cases where the input event lands on content that is async- + // scrolled into view, but Gecko still thinks it is out of view given the + // visible area of a scrollframe. + // + // Another reason we want to clear the untransform is that if our APZ hit-test + // hits a dispatch-to-content region then that's an ambiguous result and we + // need to ask Gecko what actually got hit. In order to do this we need to + // untransform the input event into Gecko space - but to do that we need to + // know which APZC got hit! This leads to a circular dependency; the only way + // to get out of it is to make sure that the untransform for all the possible + // matched APZCs is the same. It is simplest to ensure that by flushing the + // pending repaint requests, which makes all of the untransforms empty (and + // therefore equal). + RecursiveMutexAutoLock lock(mTreeLock); + + ForEachNode<ReverseIterator>(mRootNode.get(), [](HitTestingTreeNode* aNode) { + if (aNode->IsPrimaryHolder()) { + MOZ_ASSERT(aNode->GetApzc()); + aNode->GetApzc()->FlushRepaintForNewInputBlock(); + } + }); +} + +void APZCTreeManager::ClearTree() { + AssertOnUpdaterThread(); + + // Ensure that no references to APZCs are alive in any lingering input + // blocks. This breaks cycles from InputBlockState::mTargetApzc back to + // the InputQueue. + APZThreadUtils::RunOnControllerThread(NewRunnableMethod( + "layers::InputQueue::Clear", mInputQueue, &InputQueue::Clear)); + + RecursiveMutexAutoLock lock(mTreeLock); + + // Collect the nodes into a list, and then destroy each one. + // We can't destroy them as we collect them, because ForEachNode() + // does a pre-order traversal of the tree, and Destroy() nulls out + // the fields needed to reach the children of the node. + nsTArray<RefPtr<HitTestingTreeNode>> nodesToDestroy; + ForEachNode<ReverseIterator>(mRootNode.get(), + [&nodesToDestroy](HitTestingTreeNode* aNode) { + nodesToDestroy.AppendElement(aNode); + }); + + for (size_t i = 0; i < nodesToDestroy.Length(); i++) { + nodesToDestroy[i]->Destroy(); + } + mRootNode = nullptr; + + { + // Also remove references to APZC instances in the map + MutexAutoLock lock(mMapLock); + mApzcMap.clear(); + } + + RefPtr<APZCTreeManager> self(this); + NS_DispatchToMainThread( + NS_NewRunnableFunction("layers::APZCTreeManager::ClearTree", [self] { + self->mFlushObserver->Unregister(); + self->mFlushObserver = nullptr; + })); +} + +RefPtr<HitTestingTreeNode> APZCTreeManager::GetRootNode() const { + RecursiveMutexAutoLock lock(mTreeLock); + return mRootNode; +} + +/** + * Transform a displacement from the ParentLayer coordinates of a source APZC + * to the ParentLayer coordinates of a target APZC. + * @param aTreeManager the tree manager for the APZC tree containing |aSource| + * and |aTarget| + * @param aSource the source APZC + * @param aTarget the target APZC + * @param aStartPoint the start point of the displacement + * @param aEndPoint the end point of the displacement + * @return true on success, false if aStartPoint or aEndPoint cannot be + * transformed into target's coordinate space + */ +static bool TransformDisplacement(APZCTreeManager* aTreeManager, + AsyncPanZoomController* aSource, + AsyncPanZoomController* aTarget, + ParentLayerPoint& aStartPoint, + ParentLayerPoint& aEndPoint) { + if (aSource == aTarget) { + return true; + } + + // Convert start and end points to Screen coordinates. + ParentLayerToScreenMatrix4x4 untransformToApzc = + aTreeManager->GetScreenToApzcTransform(aSource).Inverse(); + ScreenPoint screenStart = TransformBy(untransformToApzc, aStartPoint); + ScreenPoint screenEnd = TransformBy(untransformToApzc, aEndPoint); + + // Convert start and end points to aTarget's ParentLayer coordinates. + ScreenToParentLayerMatrix4x4 transformToApzc = + aTreeManager->GetScreenToApzcTransform(aTarget); + Maybe<ParentLayerPoint> startPoint = + UntransformBy(transformToApzc, screenStart); + Maybe<ParentLayerPoint> endPoint = UntransformBy(transformToApzc, screenEnd); + if (!startPoint || !endPoint) { + return false; + } + aEndPoint = *endPoint; + aStartPoint = *startPoint; + + return true; +} + +bool APZCTreeManager::DispatchScroll( + AsyncPanZoomController* aPrev, ParentLayerPoint& aStartPoint, + ParentLayerPoint& aEndPoint, + OverscrollHandoffState& aOverscrollHandoffState) { + const OverscrollHandoffChain& overscrollHandoffChain = + aOverscrollHandoffState.mChain; + uint32_t overscrollHandoffChainIndex = aOverscrollHandoffState.mChainIndex; + RefPtr<AsyncPanZoomController> next; + // If we have reached the end of the overscroll handoff chain, there is + // nothing more to scroll, so we ignore the rest of the pan gesture. + if (overscrollHandoffChainIndex >= overscrollHandoffChain.Length()) { + // Nothing more to scroll - ignore the rest of the pan gesture. + return false; + } + + next = overscrollHandoffChain.GetApzcAtIndex(overscrollHandoffChainIndex); + + if (next == nullptr || next->IsDestroyed()) { + return false; + } + + // Convert the start and end points from |aPrev|'s coordinate space to + // |next|'s coordinate space. + if (!TransformDisplacement(this, aPrev, next, aStartPoint, aEndPoint)) { + return false; + } + + // Scroll |next|. If this causes overscroll, it will call DispatchScroll() + // again with an incremented index. + if (!next->AttemptScroll(aStartPoint, aEndPoint, aOverscrollHandoffState)) { + // Transform |aStartPoint| and |aEndPoint| (which now represent the + // portion of the displacement that wasn't consumed by APZCs later + // in the handoff chain) back into |aPrev|'s coordinate space. This + // allows the caller (which is |aPrev|) to interpret the unconsumed + // displacement in its own coordinate space, and make use of it + // (e.g. by going into overscroll). + if (!TransformDisplacement(this, next, aPrev, aStartPoint, aEndPoint)) { + NS_WARNING("Failed to untransform scroll points during dispatch"); + } + return false; + } + + // Return true to indicate the scroll was consumed entirely. + return true; +} + +ParentLayerPoint APZCTreeManager::DispatchFling( + AsyncPanZoomController* aPrev, const FlingHandoffState& aHandoffState) { + // If immediate handoff is disallowed, do not allow handoff beyond the + // single APZC that's scrolled by the input block that triggered this fling. + if (aHandoffState.mIsHandoff && !StaticPrefs::apz_allow_immediate_handoff() && + aHandoffState.mScrolledApzc == aPrev) { + FLING_LOG("APZCTM dropping handoff due to disallowed immediate handoff\n"); + return aHandoffState.mVelocity; + } + + const OverscrollHandoffChain* chain = aHandoffState.mChain; + RefPtr<AsyncPanZoomController> current; + uint32_t overscrollHandoffChainLength = chain->Length(); + uint32_t startIndex; + + // The fling's velocity needs to be transformed from the screen coordinates + // of |aPrev| to the screen coordinates of |next|. To transform a velocity + // correctly, we need to convert it to a displacement. For now, we do this + // by anchoring it to a start point of (0, 0). + // TODO: For this to be correct in the presence of 3D transforms, we should + // use the end point of the touch that started the fling as the start point + // rather than (0, 0). + ParentLayerPoint startPoint; // (0, 0) + ParentLayerPoint endPoint; + + if (aHandoffState.mIsHandoff) { + startIndex = chain->IndexOf(aPrev) + 1; + + // IndexOf will return aOverscrollHandoffChain->Length() if + // |aPrev| is not found. + if (startIndex >= overscrollHandoffChainLength) { + return aHandoffState.mVelocity; + } + } else { + startIndex = 0; + } + + // This will store any velocity left over after the entire handoff. + ParentLayerPoint finalResidualVelocity = aHandoffState.mVelocity; + + ParentLayerPoint currentVelocity = aHandoffState.mVelocity; + for (; startIndex < overscrollHandoffChainLength; startIndex++) { + current = chain->GetApzcAtIndex(startIndex); + + // Make sure the apzc about to be handled can be handled + if (current == nullptr || current->IsDestroyed()) { + break; + } + + endPoint = startPoint + currentVelocity; + + RefPtr<AsyncPanZoomController> prevApzc = + (startIndex > 0) ? chain->GetApzcAtIndex(startIndex - 1) : nullptr; + + // Only transform when current apzc can be transformed with previous + if (prevApzc) { + if (!TransformDisplacement(this, prevApzc, current, startPoint, + endPoint)) { + break; + } + } + + ParentLayerPoint availableVelocity = (endPoint - startPoint); + ParentLayerPoint residualVelocity; + + FlingHandoffState transformedHandoffState = aHandoffState; + transformedHandoffState.mVelocity = availableVelocity; + + // Obey overscroll-behavior. + if (prevApzc) { + residualVelocity += prevApzc->AdjustHandoffVelocityForOverscrollBehavior( + transformedHandoffState.mVelocity); + } + + residualVelocity += current->AttemptFling(transformedHandoffState); + + // If there's no residual velocity, there's nothing more to hand off. + if (IsZero(residualVelocity)) { + return ParentLayerPoint(); + } + + // If any of the velocity available to be handed off was consumed, + // subtract the proportion of consumed velocity from finalResidualVelocity. + // Note: it's important to compare |residualVelocity| to |availableVelocity| + // here and not to |transformedHandoffState.mVelocity|, since the latter + // may have been modified by AdjustHandoffVelocityForOverscrollBehavior(). + if (!FuzzyEqualsAdditive(availableVelocity.x, residualVelocity.x, + COORDINATE_EPSILON)) { + finalResidualVelocity.x *= (residualVelocity.x / availableVelocity.x); + } + if (!FuzzyEqualsAdditive(availableVelocity.y, residualVelocity.y, + COORDINATE_EPSILON)) { + finalResidualVelocity.y *= (residualVelocity.y / availableVelocity.y); + } + + currentVelocity = residualVelocity; + } + + // Return any residual velocity left over after the entire handoff process. + return finalResidualVelocity; +} + +already_AddRefed<AsyncPanZoomController> APZCTreeManager::GetTargetAPZC( + const ScrollableLayerGuid& aGuid) { + RecursiveMutexAutoLock lock(mTreeLock); + RefPtr<HitTestingTreeNode> node = GetTargetNode(aGuid, nullptr); + MOZ_ASSERT(!node || node->GetApzc()); // any node returned must have an APZC + RefPtr<AsyncPanZoomController> apzc = node ? node->GetApzc() : nullptr; + return apzc.forget(); +} + +static bool GuidComparatorIgnoringPresShell(const ScrollableLayerGuid& aOne, + const ScrollableLayerGuid& aTwo) { + return aOne.mLayersId == aTwo.mLayersId && aOne.mScrollId == aTwo.mScrollId; +} + +already_AddRefed<AsyncPanZoomController> APZCTreeManager::GetTargetAPZC( + const LayersId& aLayersId, + const ScrollableLayerGuid::ViewID& aScrollId) const { + MutexAutoLock lock(mMapLock); + ScrollableLayerGuid guid(aLayersId, 0, aScrollId); + auto it = mApzcMap.find(guid); + RefPtr<AsyncPanZoomController> apzc = + (it != mApzcMap.end() ? it->second.apzc : nullptr); + return apzc.forget(); +} + +already_AddRefed<HitTestingTreeNode> APZCTreeManager::GetTargetNode( + const ScrollableLayerGuid& aGuid, GuidComparator aComparator) const { + mTreeLock.AssertCurrentThreadIn(); + RefPtr<HitTestingTreeNode> target = + DepthFirstSearchPostOrder<ReverseIterator>( + mRootNode.get(), [&aGuid, &aComparator](HitTestingTreeNode* node) { + bool matches = false; + if (node->GetApzc()) { + if (aComparator) { + matches = aComparator(aGuid, node->GetApzc()->GetGuid()); + } else { + matches = node->GetApzc()->Matches(aGuid); + } + } + return matches; + }); + return target.forget(); +} + +APZCTreeManager::HitTestResult APZCTreeManager::GetTargetAPZC( + const ScreenPoint& aPoint) { + RecursiveMutexAutoLock lock(mTreeLock); + if (mIsUsingWebRender) { + return GetAPZCAtPointWR(aPoint, lock); + } + return GetAPZCAtPoint(aPoint, lock); +} + +APZCTreeManager::HitTestResult APZCTreeManager::GetAPZCAtPointWR( + const ScreenPoint& aHitTestPoint, + const RecursiveMutexAutoLock& aProofOfTreeLock) { + HitTestResult hit; + RefPtr<wr::WebRenderAPI> wr = GetWebRenderAPI(); + if (!wr) { + // If WebRender isn't running, fall back to the root APZC. + // This is mostly for the benefit of GTests which do not + // run a WebRender instance, but gracefully falling back + // here allows those tests which are not specifically + // testing the hit-test algorithm to still work. + hit.mTargetApzc = FindRootApzcForLayersId(mRootLayersId); + hit.mHitResult = CompositorHitTestFlags::eVisibleToHitTest; + return hit; + } + + APZCTM_LOG("Hit-testing point %s with WR\n", ToString(aHitTestPoint).c_str()); + std::vector<wr::WrHitResult> results = + wr->HitTest(wr::ToWorldPoint(aHitTestPoint)); + + Maybe<wr::WrHitResult> chosenResult; + for (const wr::WrHitResult& result : results) { + ScrollableLayerGuid guid{result.mLayersId, 0, result.mScrollId}; + APZCTM_LOG("Examining result with guid %s hit info 0x%x... ", + ToString(guid).c_str(), result.mHitInfo.serialize()); + if (result.mHitInfo == CompositorHitTestInvisibleToHit) { + APZCTM_LOG("skipping due to invisibility.\n"); + continue; + } + RefPtr<HitTestingTreeNode> node = + GetTargetNode(guid, &GuidComparatorIgnoringPresShell); + if (!node) { + APZCTM_LOG("no corresponding node found, falling back to root.\n"); + // We can enter here during normal codepaths for cases where the + // nsDisplayCompositorHitTestInfo item emitted a scrollId of + // NULL_SCROLL_ID to the webrender display list. The semantics of that + // is to fall back to the root APZC for the layers id, so that's what + // we do here. + // If we enter this codepath and scrollId is not NULL_SCROLL_ID, then + // that's more likely to be due to a race condition between rebuilding + // the APZ tree and updating the WR scene/hit-test information, resulting + // in WR giving us a hit result for a scene that is not active in APZ. + // Such a scenario would need debugging and fixing. + MOZ_ASSERT(result.mScrollId == ScrollableLayerGuid::NULL_SCROLL_ID); + node = FindRootNodeForLayersId(result.mLayersId); + if (!node) { + // Should never happen, but handle gracefully in release builds just + // in case. + MOZ_ASSERT(false); + chosenResult = Some(result); + break; + } + } + MOZ_ASSERT(node->GetApzc()); // any node returned must have an APZC + EventRegionsOverride flags = node->GetEventRegionsOverride(); + if (flags & EventRegionsOverride::ForceEmptyHitRegion) { + // This result is inside a subtree that is invisible to hit-testing. + APZCTM_LOG("skipping due to FEHR subtree.\n"); + continue; + } + + APZCTM_LOG("selecting as chosen result.\n"); + chosenResult = Some(result); + hit.mTargetApzc = node->GetApzc(); + if (flags & EventRegionsOverride::ForceDispatchToContent) { + chosenResult->mHitInfo += CompositorHitTestFlags::eApzAwareListeners; + } + break; + } + if (!chosenResult) { + return hit; + } + + MOZ_ASSERT(hit.mTargetApzc); + hit.mLayersId = chosenResult->mLayersId; + ScrollableLayerGuid::ViewID scrollId = chosenResult->mScrollId; + gfx::CompositorHitTestInfo hitInfo = chosenResult->mHitInfo; + SideBits sideBits = chosenResult->mSideBits; + + APZCTM_LOG("Successfully matched APZC %p (hit result 0x%x)\n", + hit.mTargetApzc.get(), hitInfo.serialize()); + + const bool isScrollbar = + hitInfo.contains(gfx::CompositorHitTestFlags::eScrollbar); + const bool isScrollbarThumb = + hitInfo.contains(gfx::CompositorHitTestFlags::eScrollbarThumb); + const ScrollDirection direction = + hitInfo.contains(gfx::CompositorHitTestFlags::eScrollbarVertical) + ? ScrollDirection::eVertical + : ScrollDirection::eHorizontal; + HitTestingTreeNode* scrollbarNode = nullptr; + if (isScrollbar || isScrollbarThumb) { + scrollbarNode = BreadthFirstSearch<ReverseIterator>( + mRootNode.get(), [&](HitTestingTreeNode* aNode) { + return (aNode->GetLayersId() == hit.mLayersId) && + (aNode->IsScrollbarNode() == isScrollbar) && + (aNode->IsScrollThumbNode() == isScrollbarThumb) && + (aNode->GetScrollbarDirection() == direction) && + (aNode->GetScrollTargetId() == scrollId); + }); + } + + hit.mHitResult = hitInfo; + + if (scrollbarNode) { + RefPtr<HitTestingTreeNode> scrollbarRef = scrollbarNode; + hit.mScrollbarNode.Initialize(aProofOfTreeLock, scrollbarRef.forget(), + mTreeLock); + } + + hit.mFixedPosSides = sideBits; + + return hit; +} + +RefPtr<const OverscrollHandoffChain> +APZCTreeManager::BuildOverscrollHandoffChain( + const RefPtr<AsyncPanZoomController>& aInitialTarget) { + // Scroll grabbing is a mechanism that allows content to specify that + // the initial target of a pan should be not the innermost scrollable + // frame at the touch point (which is what GetTargetAPZC finds), but + // something higher up in the tree. + // It's not sufficient to just find the initial target, however, as + // overscroll can be handed off to another APZC. Without scroll grabbing, + // handoff just occurs from child to parent. With scroll grabbing, the + // handoff order can be different, so we build a chain of APZCs in the + // order in which scroll will be handed off to them. + + // Grab tree lock since we'll be walking the APZC tree. + RecursiveMutexAutoLock lock(mTreeLock); + + // Build the chain. If there is a scroll parent link, we use that. This is + // needed to deal with scroll info layers, because they participate in handoff + // but do not follow the expected layer tree structure. If there are no + // scroll parent links we just walk up the tree to find the scroll parent. + OverscrollHandoffChain* result = new OverscrollHandoffChain; + AsyncPanZoomController* apzc = aInitialTarget; + while (apzc != nullptr) { + result->Add(apzc); + + if (apzc->GetScrollHandoffParentId() == + ScrollableLayerGuid::NULL_SCROLL_ID) { + if (!apzc->IsRootForLayersId()) { + // This probably indicates a bug or missed case in layout code + NS_WARNING("Found a non-root APZ with no handoff parent"); + } + apzc = apzc->GetParent(); + continue; + } + + // Guard against a possible infinite-loop condition. If we hit this, the + // layout code that generates the handoff parents did something wrong. + MOZ_ASSERT(apzc->GetScrollHandoffParentId() != apzc->GetGuid().mScrollId); + RefPtr<AsyncPanZoomController> scrollParent = GetTargetAPZC( + apzc->GetGuid().mLayersId, apzc->GetScrollHandoffParentId()); + apzc = scrollParent.get(); + } + + // Now adjust the chain to account for scroll grabbing. Sorting is a bit + // of an overkill here, but scroll grabbing will likely be generalized + // to scroll priorities, so we might as well do it this way. + result->SortByScrollPriority(); + + // Print the overscroll chain for debugging. + for (uint32_t i = 0; i < result->Length(); ++i) { + APZCTM_LOG("OverscrollHandoffChain[%d] = %p\n", i, + result->GetApzcAtIndex(i).get()); + } + + return result; +} + +void APZCTreeManager::SetLongTapEnabled(bool aLongTapEnabled) { + APZThreadUtils::AssertOnControllerThread(); + GestureEventListener::SetLongTapEnabled(aLongTapEnabled); +} + +void APZCTreeManager::AddInputBlockCallback(uint64_t aInputBlockId, + InputBlockCallback&& aCallback) { + mInputQueue->AddInputBlockCallback(aInputBlockId, std::move(aCallback)); +} + +void APZCTreeManager::FindScrollThumbNode( + const AsyncDragMetrics& aDragMetrics, + HitTestingTreeNodeAutoLock& aOutThumbNode) { + if (!aDragMetrics.mDirection) { + // The AsyncDragMetrics has not been initialized yet - there will be + // no matching node, so don't bother searching the tree. + return; + } + + RecursiveMutexAutoLock lock(mTreeLock); + + RefPtr<HitTestingTreeNode> result = DepthFirstSearch<ReverseIterator>( + mRootNode.get(), [&aDragMetrics](HitTestingTreeNode* aNode) { + return aNode->MatchesScrollDragMetrics(aDragMetrics); + }); + if (result) { + aOutThumbNode.Initialize(lock, result.forget(), mTreeLock); + } +} + +AsyncPanZoomController* APZCTreeManager::GetTargetApzcForNode( + HitTestingTreeNode* aNode) { + for (const HitTestingTreeNode* n = aNode; + n && n->GetLayersId() == aNode->GetLayersId(); n = n->GetParent()) { + if (n->GetApzc()) { + APZCTM_LOG("Found target %p using ancestor lookup\n", n->GetApzc()); + return n->GetApzc(); + } + if (n->GetFixedPosTarget() != ScrollableLayerGuid::NULL_SCROLL_ID) { + RefPtr<AsyncPanZoomController> fpTarget = + GetTargetAPZC(n->GetLayersId(), n->GetFixedPosTarget()); + APZCTM_LOG("Found target APZC %p using fixed-pos lookup on %" PRIu64 "\n", + fpTarget.get(), n->GetFixedPosTarget()); + return fpTarget.get(); + } + } + return nullptr; +} + +APZCTreeManager::HitTestResult APZCTreeManager::GetAPZCAtPoint( + const ScreenPoint& aHitTestPoint, + const RecursiveMutexAutoLock& aProofOfTreeLock) { + HitTestResult hit; + // This walks the tree in depth-first, reverse order, so that it encounters + // APZCs front-to-back on the screen. + HitTestingTreeNode* resultNode; + HitTestingTreeNode* root = mRootNode; + HitTestingTreeNode* scrollbarNode = nullptr; + std::stack<LayerPoint> hitTestPoints; + ParentLayerPoint point = ViewAs<ParentLayerPixel>( + aHitTestPoint, PixelCastJustification::ScreenIsParentLayerForRoot); + hitTestPoints.push( + ViewAs<LayerPixel>(point, PixelCastJustification::MovingDownToChildren)); + + ForEachNode<ReverseIterator>( + root, + [&hitTestPoints, this](HitTestingTreeNode* aNode) { + ParentLayerPoint hitTestPointForParent = ViewAs<ParentLayerPixel>( + hitTestPoints.top(), PixelCastJustification::MovingDownToChildren); + if (aNode->IsOutsideClip(hitTestPointForParent)) { + // If the point being tested is outside the clip region for this node + // then we don't need to test against this node or any of its + // children. Just skip it and move on. + APZCTM_LOG("Point %f %f outside clip for node %p\n", + hitTestPoints.top().x, hitTestPoints.top().y, aNode); + return TraversalFlag::Skip; + } + // First check the subtree rooted at this node, because deeper nodes + // are more "in front". + Maybe<LayerPoint> hitTestPoint = aNode->Untransform( + hitTestPointForParent, ComputeTransformForNode(aNode)); + APZCTM_LOG("Transformed ParentLayer point %s to layer %s\n", + ToString(hitTestPointForParent).c_str(), + hitTestPoint ? ToString(hitTestPoint.ref()).c_str() : "nil"); + if (!hitTestPoint) { + return TraversalFlag::Skip; + } + hitTestPoints.push(hitTestPoint.ref()); + return TraversalFlag::Continue; + }, + [&resultNode, &hitTestPoints, &hit](HitTestingTreeNode* aNode) { + CompositorHitTestInfo hitResult = aNode->HitTest(hitTestPoints.top()); + hitTestPoints.pop(); + APZCTM_LOG("Testing Layer point %s against node %p\n", + ToString(hitTestPoints.top()).c_str(), aNode); + if (hitResult != CompositorHitTestInvisibleToHit) { + resultNode = aNode; + hit.mHitResult = hitResult; + return TraversalFlag::Abort; + } + return TraversalFlag::Continue; + }); + + if (hit.mHitResult != CompositorHitTestInvisibleToHit) { + MOZ_ASSERT(resultNode); + for (HitTestingTreeNode* n = resultNode; n; n = n->GetParent()) { + if (n->IsScrollbarNode()) { + scrollbarNode = n; + hit.mHitResult += CompositorHitTestFlags::eScrollbar; + if (n->IsScrollThumbNode()) { + hit.mHitResult += CompositorHitTestFlags::eScrollbarThumb; + } + if (n->GetScrollbarDirection() == ScrollDirection::eVertical) { + hit.mHitResult += CompositorHitTestFlags::eScrollbarVertical; + } + + // If we hit a scrollbar, target the APZC for the content scrolled + // by the scrollbar. (The scrollbar itself doesn't scroll with the + // scrolled content, so it doesn't carry the scrolled content's + // scroll metadata). + RefPtr<AsyncPanZoomController> scrollTarget = + GetTargetAPZC(n->GetLayersId(), n->GetScrollTargetId()); + if (scrollTarget) { + hit.mLayersId = n->GetLayersId(); + hit.mTargetApzc = std::move(scrollTarget); + RefPtr<HitTestingTreeNode> scrollbarRef = scrollbarNode; + hit.mScrollbarNode.Initialize(aProofOfTreeLock, scrollbarRef.forget(), + mTreeLock); + return hit; + } + } else if (IsFixedToRootContent(n)) { + hit.mFixedPosSides = n->GetFixedPosSides(); + } + } + + hit.mTargetApzc = GetTargetApzcForNode(resultNode); + if (!hit.mTargetApzc) { + hit.mTargetApzc = FindRootApzcForLayersId(resultNode->GetLayersId()); + MOZ_ASSERT(hit.mTargetApzc); + APZCTM_LOG("Found target %p using root lookup\n", hit.mTargetApzc.get()); + } + APZCTM_LOG("Successfully matched APZC %p via node %p (hit result 0x%x)\n", + hit.mTargetApzc.get(), resultNode, hit.mHitResult.serialize()); + hit.mLayersId = resultNode->GetLayersId(); + + return hit; + } + + return hit; +} + +HitTestingTreeNode* APZCTreeManager::FindRootNodeForLayersId( + LayersId aLayersId) const { + mTreeLock.AssertCurrentThreadIn(); + + HitTestingTreeNode* resultNode = BreadthFirstSearch<ReverseIterator>( + mRootNode.get(), [aLayersId](HitTestingTreeNode* aNode) { + AsyncPanZoomController* apzc = aNode->GetApzc(); + return apzc && apzc->GetLayersId() == aLayersId && + apzc->IsRootForLayersId(); + }); + return resultNode; +} + +AsyncPanZoomController* APZCTreeManager::FindRootApzcForLayersId( + LayersId aLayersId) const { + mTreeLock.AssertCurrentThreadIn(); + + HitTestingTreeNode* resultNode = FindRootNodeForLayersId(aLayersId); + return resultNode ? resultNode->GetApzc() : nullptr; +} + +already_AddRefed<AsyncPanZoomController> APZCTreeManager::FindZoomableApzc( + AsyncPanZoomController* aStart) const { + return GetZoomableTarget(aStart, aStart); +} + +ScreenMargin APZCTreeManager::GetGeckoFixedLayerMargins() const { + RecursiveMutexAutoLock lock(mTreeLock); + return mGeckoFixedLayerMargins; +} + +AsyncPanZoomController* APZCTreeManager::FindRootContentApzcForLayersId( + LayersId aLayersId) const { + mTreeLock.AssertCurrentThreadIn(); + + HitTestingTreeNode* resultNode = BreadthFirstSearch<ReverseIterator>( + mRootNode.get(), [aLayersId](HitTestingTreeNode* aNode) { + AsyncPanZoomController* apzc = aNode->GetApzc(); + return apzc && apzc->GetLayersId() == aLayersId && + apzc->IsRootContent(); + }); + return resultNode ? resultNode->GetApzc() : nullptr; +} + +// clang-format off +/* The methods GetScreenToApzcTransform() and GetApzcToGeckoTransform() return + some useful transformations that input events may need applied. This is best + illustrated with an example. Consider a chain of layers, L, M, N, O, P, Q, R. Layer L + is the layer that corresponds to the argument |aApzc|, and layer R is the root + of the layer tree. Layer M is the parent of L, N is the parent of M, and so on. + When layer L is displayed to the screen by the compositor, the set of transforms that + are applied to L are (in order from top to bottom): + + L's CSS transform (hereafter referred to as transform matrix LC) + L's nontransient async transform (hereafter referred to as transform matrix LN) + L's transient async transform (hereafter referred to as transform matrix LT) + M's CSS transform (hereafter referred to as transform matrix MC) + M's nontransient async transform (hereafter referred to as transform matrix MN) + M's transient async transform (hereafter referred to as transform matrix MT) + ... + R's CSS transform (hereafter referred to as transform matrix RC) + R's nontransient async transform (hereafter referred to as transform matrix RN) + R's transient async transform (hereafter referred to as transform matrix RT) + + Also, for any layer, the async transform is the combination of its transient and non-transient + parts. That is, for any layer L: + LA === LN * LT + LA.Inverse() === LT.Inverse() * LN.Inverse() + + If we want user input to modify L's transient async transform, we have to first convert + user input from screen space to the coordinate space of L's transient async transform. Doing + this involves applying the following transforms (in order from top to bottom): + RT.Inverse() + RN.Inverse() + RC.Inverse() + ... + MT.Inverse() + MN.Inverse() + MC.Inverse() + This combined transformation is returned by GetScreenToApzcTransform(). + + Next, if we want user inputs sent to gecko for event-dispatching, we will need to strip + out all of the async transforms that are involved in this chain. This is because async + transforms are stored only in the compositor and gecko does not account for them when + doing display-list-based hit-testing for event dispatching. + Furthermore, because these input events are processed by Gecko in a FIFO queue that + includes other things (specifically paint requests), it is possible that by time the + input event reaches gecko, it will have painted something else. Therefore, we need to + apply another transform to the input events to account for the possible disparity between + what we know gecko last painted and the last paint request we sent to gecko. Let this + transform be represented by LD, MD, ... RD. + Therefore, given a user input in screen space, the following transforms need to be applied + (in order from top to bottom): + RT.Inverse() + RN.Inverse() + RC.Inverse() + ... + MT.Inverse() + MN.Inverse() + MC.Inverse() + LT.Inverse() + LN.Inverse() + LC.Inverse() + LC + LD + MC + MD + ... + RC + RD + This sequence can be simplified and refactored to the following: + GetScreenToApzcTransform() + LA.Inverse() + LD + MC + MD + ... + RC + RD + Since GetScreenToApzcTransform() can be obtained by calling that function, GetApzcToGeckoTransform() + returns the remaining transforms (LA.Inverse() * LD * ... * RD), so that the caller code can + combine it with GetScreenToApzcTransform() to get the final transform required in this case. + + Note that for many of these layers, there will be no AsyncPanZoomController attached, and + so the async transform will be the identity transform. So, in the example above, if layers + L and P have APZC instances attached, MT, MN, MD, NT, NN, ND, OT, ON, OD, QT, QN, QD, RT, + RN and RD will be identity transforms. + Additionally, for space-saving purposes, each APZC instance stores its layer's individual + CSS transform and the accumulation of CSS transforms to its parent APZC. So the APZC for + layer L would store LC and (MC * NC * OC), and the layer P would store PC and (QC * RC). + The APZC instances track the last dispatched paint request and so are able to calculate LD and + PD using those internally stored values. + The APZCs also obviously have LT, LN, PT, and PN, so all of the above transformation combinations + required can be generated. + */ +// clang-format on + +/* + * See the long comment above for a detailed explanation of this function. + */ +ScreenToParentLayerMatrix4x4 APZCTreeManager::GetScreenToApzcTransform( + const AsyncPanZoomController* aApzc) const { + Matrix4x4 result; + RecursiveMutexAutoLock lock(mTreeLock); + + // The comments below assume there is a chain of layers L..R with L and P + // having APZC instances as explained in the comment above. This function is + // called with aApzc at L, and the loop below performs one iteration, where + // parent is at P. The comments explain what values are stored in the + // variables at these two levels. All the comments use standard matrix + // notation where the leftmost matrix in a multiplication is applied first. + + // ancestorUntransform is PC.Inverse() * OC.Inverse() * NC.Inverse() * + // MC.Inverse() + Matrix4x4 ancestorUntransform = aApzc->GetAncestorTransform().Inverse(); + + // result is initialized to PC.Inverse() * OC.Inverse() * NC.Inverse() * + // MC.Inverse() + result = ancestorUntransform; + + for (AsyncPanZoomController* parent = aApzc->GetParent(); parent; + parent = parent->GetParent()) { + // ancestorUntransform is updated to RC.Inverse() * QC.Inverse() when parent + // == P + ancestorUntransform = parent->GetAncestorTransform().Inverse(); + // asyncUntransform is updated to PA.Inverse() when parent == P + Matrix4x4 asyncUntransform = parent + ->GetCurrentAsyncTransformWithOverscroll( + AsyncPanZoomController::eForHitTesting) + .Inverse() + .ToUnknownMatrix(); + // untransformSinceLastApzc is RC.Inverse() * QC.Inverse() * PA.Inverse() + Matrix4x4 untransformSinceLastApzc = ancestorUntransform * asyncUntransform; + + // result is RC.Inverse() * QC.Inverse() * PA.Inverse() * PC.Inverse() * + // OC.Inverse() * NC.Inverse() * MC.Inverse() + result = untransformSinceLastApzc * result; + + // The above value for result when parent == P matches the required output + // as explained in the comment above this method. Note that any missing + // terms are guaranteed to be identity transforms. + } + + return ViewAs<ScreenToParentLayerMatrix4x4>(result); +} + +/* + * See the long comment above GetScreenToApzcTransform() for a detailed + * explanation of this function. + */ +ParentLayerToScreenMatrix4x4 APZCTreeManager::GetApzcToGeckoTransform( + const AsyncPanZoomController* aApzc) const { + Matrix4x4 result; + RecursiveMutexAutoLock lock(mTreeLock); + + // The comments below assume there is a chain of layers L..R with L and P + // having APZC instances as explained in the comment above. This function is + // called with aApzc at L, and the loop below performs one iteration, where + // parent is at P. The comments explain what values are stored in the + // variables at these two levels. All the comments use standard matrix + // notation where the leftmost matrix in a multiplication is applied first. + + // asyncUntransform is LA.Inverse() + Matrix4x4 asyncUntransform = aApzc + ->GetCurrentAsyncTransformWithOverscroll( + AsyncPanZoomController::eForHitTesting) + .Inverse() + .ToUnknownMatrix(); + + // aTransformToGeckoOut is initialized to LA.Inverse() * LD * MC * NC * OC * + // PC + result = asyncUntransform * aApzc->GetTransformToLastDispatchedPaint() * + aApzc->GetAncestorTransform(); + + for (AsyncPanZoomController* parent = aApzc->GetParent(); parent; + parent = parent->GetParent()) { + // aTransformToGeckoOut is LA.Inverse() * LD * MC * NC * OC * PC * PD * QC * + // RC + result = result * parent->GetTransformToLastDispatchedPaint() * + parent->GetAncestorTransform(); + + // The above value for result when parent == P matches the required output + // as explained in the comment above this method. Note that any missing + // terms are guaranteed to be identity transforms. + } + + return ViewAs<ParentLayerToScreenMatrix4x4>(result); +} + +ScreenPoint APZCTreeManager::GetCurrentMousePosition() const { + auto pos = mCurrentMousePosition.Lock(); + return pos.ref(); +} + +void APZCTreeManager::SetCurrentMousePosition(const ScreenPoint& aNewPos) { + auto pos = mCurrentMousePosition.Lock(); + pos.ref() = aNewPos; +} + +already_AddRefed<AsyncPanZoomController> APZCTreeManager::GetZoomableTarget( + AsyncPanZoomController* aApzc1, AsyncPanZoomController* aApzc2) const { + RecursiveMutexAutoLock lock(mTreeLock); + RefPtr<AsyncPanZoomController> apzc; + // For now, we only ever want to do pinching on the root-content APZC for + // a given layers id. + if (aApzc1 && aApzc2 && aApzc1->GetLayersId() == aApzc2->GetLayersId()) { + // If the two APZCs have the same layers id, find the root-content APZC + // for that layers id. Don't call CommonAncestor() because there may not + // be a common ancestor for the layers id (e.g. if one APZCs is inside a + // fixed-position element). + apzc = FindRootContentApzcForLayersId(aApzc1->GetLayersId()); + } else { + // Otherwise, find the common ancestor (to reach a common layers id), and + // get the root-content APZC for that layers id. + apzc = CommonAncestor(aApzc1, aApzc2); + if (apzc) { + apzc = FindRootContentApzcForLayersId(apzc->GetLayersId()); + } + } + return apzc.forget(); +} + +Maybe<ScreenIntPoint> APZCTreeManager::ConvertToGecko( + const ScreenIntPoint& aPoint, AsyncPanZoomController* aApzc) { + RecursiveMutexAutoLock lock(mTreeLock); + ScreenToScreenMatrix4x4 transformScreenToGecko = + GetScreenToApzcTransform(aApzc) * GetApzcToGeckoTransform(aApzc); + Maybe<ScreenIntPoint> geckoPoint = + UntransformBy(transformScreenToGecko, aPoint); + if (geckoPoint) { + if (mTouchBlockHitResult.mFixedPosSides != SideBits::eNone) { + MutexAutoLock mapLock(mMapLock); + *geckoPoint -= RoundedToInt(apz::ComputeFixedMarginsOffset( + GetCompositorFixedLayerMargins(mapLock), + mTouchBlockHitResult.mFixedPosSides, mGeckoFixedLayerMargins)); + } + } + return geckoPoint; +} + +already_AddRefed<AsyncPanZoomController> APZCTreeManager::CommonAncestor( + AsyncPanZoomController* aApzc1, AsyncPanZoomController* aApzc2) const { + mTreeLock.AssertCurrentThreadIn(); + RefPtr<AsyncPanZoomController> ancestor; + + // If either aApzc1 or aApzc2 is null, min(depth1, depth2) will be 0 and this + // function will return null. + + // Calculate depth of the APZCs in the tree + int depth1 = 0, depth2 = 0; + for (AsyncPanZoomController* parent = aApzc1; parent; + parent = parent->GetParent()) { + depth1++; + } + for (AsyncPanZoomController* parent = aApzc2; parent; + parent = parent->GetParent()) { + depth2++; + } + + // At most one of the following two loops will be executed; the deeper APZC + // pointer will get walked up to the depth of the shallower one. + int minDepth = depth1 < depth2 ? depth1 : depth2; + while (depth1 > minDepth) { + depth1--; + aApzc1 = aApzc1->GetParent(); + } + while (depth2 > minDepth) { + depth2--; + aApzc2 = aApzc2->GetParent(); + } + + // Walk up the ancestor chains of both APZCs, always staying at the same depth + // for either APZC, and return the the first common ancestor encountered. + while (true) { + if (aApzc1 == aApzc2) { + ancestor = aApzc1; + break; + } + if (depth1 <= 0) { + break; + } + aApzc1 = aApzc1->GetParent(); + aApzc2 = aApzc2->GetParent(); + } + return ancestor.forget(); +} + +bool APZCTreeManager::IsFixedToRootContent( + const HitTestingTreeNode* aNode) const { + MutexAutoLock lock(mMapLock); + return IsFixedToRootContent(FixedPositionInfo(aNode), lock); +} + +bool APZCTreeManager::IsFixedToRootContent( + const FixedPositionInfo& aFixedInfo, + const MutexAutoLock& aProofOfMapLock) const { + ScrollableLayerGuid::ViewID fixedTarget = aFixedInfo.mFixedPosTarget; + if (fixedTarget == ScrollableLayerGuid::NULL_SCROLL_ID) { + return false; + } + auto it = + mApzcMap.find(ScrollableLayerGuid(aFixedInfo.mLayersId, 0, fixedTarget)); + if (it == mApzcMap.end()) { + return false; + } + RefPtr<AsyncPanZoomController> targetApzc = it->second.apzc; + return targetApzc && targetApzc->IsRootContent(); +} + +SideBits APZCTreeManager::SidesStuckToRootContent( + const HitTestingTreeNode* aNode) const { + MutexAutoLock lock(mMapLock); + return SidesStuckToRootContent(StickyPositionInfo(aNode), lock); +} + +SideBits APZCTreeManager::SidesStuckToRootContent( + const StickyPositionInfo& aStickyInfo, + const MutexAutoLock& aProofOfMapLock) const { + SideBits result = SideBits::eNone; + + ScrollableLayerGuid::ViewID stickyTarget = aStickyInfo.mStickyPosTarget; + if (stickyTarget == ScrollableLayerGuid::NULL_SCROLL_ID) { + return result; + } + + // We support the dynamic toolbar at top and bottom. + if ((aStickyInfo.mFixedPosSides & SideBits::eTopBottom) == SideBits::eNone) { + return result; + } + + auto it = mApzcMap.find( + ScrollableLayerGuid(aStickyInfo.mLayersId, 0, stickyTarget)); + if (it == mApzcMap.end()) { + return result; + } + RefPtr<AsyncPanZoomController> stickyTargetApzc = it->second.apzc; + if (!stickyTargetApzc || !stickyTargetApzc->IsRootContent()) { + return result; + } + + ParentLayerPoint translation = + stickyTargetApzc + ->GetCurrentAsyncTransform( + AsyncPanZoomController::eForHitTesting, + AsyncTransformComponents{AsyncTransformComponent::eLayout}) + .mTranslation; + + if (apz::IsStuckAtTop(translation.y, aStickyInfo.mStickyScrollRangeInner, + aStickyInfo.mStickyScrollRangeOuter)) { + result |= SideBits::eTop; + } + if (apz::IsStuckAtBottom(translation.y, aStickyInfo.mStickyScrollRangeInner, + aStickyInfo.mStickyScrollRangeOuter)) { + result |= SideBits::eBottom; + } + return result; +} + +LayerToParentLayerMatrix4x4 APZCTreeManager::ComputeTransformForNode( + const HitTestingTreeNode* aNode) const { + mTreeLock.AssertCurrentThreadIn(); + // The async transforms applied here for hit-testing purposes, are intended + // to match the ones AsyncCompositionManager (or equivalent WebRender code) + // applies for rendering purposes. + // Note that with containerless scrolling, the layer structure looks like + // this: + // + // root container layer + // async zoom container layer + // scrollable content layers (with scroll metadata) + // fixed content layers (no scroll metadta, annotated isFixedPosition) + // scrollbar layers + // + // The intended async transforms in this case are: + // * On the async zoom container layer, the "visual" portion of the root + // content APZC's async transform (which includes the zoom, and async + // scrolling of the visual viewport relative to the layout viewport). + // * On the scrollable layers bearing the root content APZC's scroll + // metadata, the "layout" portion of the root content APZC's async + // transform (which includes async scrolling of the layout viewport + // relative to the visual viewport). + if (AsyncPanZoomController* apzc = aNode->GetApzc()) { + // If the node represents scrollable content, apply the async transform + // from its APZC. + bool visualTransformIsInheritedFromAncestor = + /* we're the APZC whose visual transform might be on the async + zoom container */ + apzc->IsRootContent() && + /* there is an async zoom container on this subtree */ + mAsyncZoomContainerSubtree == Some(aNode->GetLayersId()) && + /* it's not us */ + !aNode->IsAsyncZoomContainer(); + AsyncTransformComponents components = + visualTransformIsInheritedFromAncestor + ? AsyncTransformComponents{AsyncTransformComponent::eLayout} + : LayoutAndVisual; + return aNode->GetTransform() * + CompleteAsyncTransform(apzc->GetCurrentAsyncTransformWithOverscroll( + AsyncPanZoomController::eForHitTesting, components)); + } else if (aNode->IsAsyncZoomContainer()) { + if (AsyncPanZoomController* rootContent = + FindRootContentApzcForLayersId(aNode->GetLayersId())) { + return aNode->GetTransform() * + CompleteAsyncTransform( + rootContent->GetCurrentAsyncTransformWithOverscroll( + AsyncPanZoomController::eForHitTesting, + {AsyncTransformComponent::eVisual})); + } + } else if (aNode->IsScrollThumbNode()) { + // If the node represents a scrollbar thumb, compute and apply the + // transformation that will be applied to the thumb in + // AsyncCompositionManager. + ScrollableLayerGuid guid{aNode->GetLayersId(), 0, + aNode->GetScrollTargetId()}; + if (RefPtr<HitTestingTreeNode> scrollTargetNode = + GetTargetNode(guid, &GuidComparatorIgnoringPresShell)) { + AsyncPanZoomController* scrollTargetApzc = scrollTargetNode->GetApzc(); + MOZ_ASSERT(scrollTargetApzc); + return scrollTargetApzc->CallWithLastContentPaintMetrics( + [&](const FrameMetrics& aMetrics) { + return ComputeTransformForScrollThumb( + aNode->GetTransform() * AsyncTransformMatrix(), + scrollTargetNode->GetTransform().ToUnknownMatrix(), + scrollTargetApzc, aMetrics, aNode->GetScrollbarData(), + scrollTargetNode->IsAncestorOf(aNode), nullptr); + }); + } + } else if (IsFixedToRootContent(aNode)) { + ParentLayerPoint translation; + { + MutexAutoLock mapLock(mMapLock); + translation = ViewAs<ParentLayerPixel>( + apz::ComputeFixedMarginsOffset( + GetCompositorFixedLayerMargins(mapLock), + aNode->GetFixedPosSides(), mGeckoFixedLayerMargins), + PixelCastJustification::ScreenIsParentLayerForRoot); + } + return aNode->GetTransform() * + CompleteAsyncTransform( + AsyncTransformComponentMatrix::Translation(translation)); + } + SideBits sides = SidesStuckToRootContent(aNode); + if (sides != SideBits::eNone) { + ParentLayerPoint translation; + { + MutexAutoLock mapLock(mMapLock); + translation = ViewAs<ParentLayerPixel>( + apz::ComputeFixedMarginsOffset( + GetCompositorFixedLayerMargins(mapLock), sides, + // For sticky layers, we don't need to factor + // mGeckoFixedLayerMargins because Gecko doesn't shift the + // position of sticky elements for dynamic toolbar movements. + ScreenMargin()), + PixelCastJustification::ScreenIsParentLayerForRoot); + } + return aNode->GetTransform() * + CompleteAsyncTransform( + AsyncTransformComponentMatrix::Translation(translation)); + } + // Otherwise, the node does not have an async transform. + return aNode->GetTransform() * AsyncTransformMatrix(); +} + +already_AddRefed<wr::WebRenderAPI> APZCTreeManager::GetWebRenderAPI() const { + RefPtr<wr::WebRenderAPI> api; + CompositorBridgeParent::CallWithIndirectShadowTree( + mRootLayersId, [&](LayerTreeState& aState) -> void { + if (aState.mWrBridge) { + api = aState.mWrBridge->GetWebRenderAPI(); + } + }); + return api.forget(); +} + +/*static*/ +already_AddRefed<GeckoContentController> APZCTreeManager::GetContentController( + LayersId aLayersId) { + RefPtr<GeckoContentController> controller; + CompositorBridgeParent::CallWithIndirectShadowTree( + aLayersId, + [&](LayerTreeState& aState) -> void { controller = aState.mController; }); + return controller.forget(); +} + +ScreenMargin APZCTreeManager::GetCompositorFixedLayerMargins( + const MutexAutoLock& aProofOfMapLock) const { + ScreenMargin result = mCompositorFixedLayerMargins; + if (StaticPrefs::apz_fixed_margin_override_enabled()) { + result.top = StaticPrefs::apz_fixed_margin_override_top(); + result.bottom = StaticPrefs::apz_fixed_margin_override_bottom(); + } + return result; +} + +bool APZCTreeManager::GetAPZTestData(LayersId aLayersId, + APZTestData* aOutData) { + AssertOnUpdaterThread(); + + { // copy the relevant test data into aOutData while holding the + // mTestDataLock + MutexAutoLock lock(mTestDataLock); + auto it = mTestData.find(aLayersId); + if (it == mTestData.end()) { + return false; + } + *aOutData = *(it->second); + } + + { // add some additional "current state" into the returned APZTestData + MutexAutoLock mapLock(mMapLock); + + ClippedCompositionBoundsMap clippedCompBounds; + for (const auto& mapping : mApzcMap) { + if (mapping.first.mLayersId != aLayersId) { + continue; + } + + ParentLayerRect clippedBounds = ComputeClippedCompositionBounds( + mapLock, clippedCompBounds, mapping.first); + AsyncPanZoomController* apzc = mapping.second.apzc; + std::string viewId = std::to_string(mapping.first.mScrollId); + std::string apzcState; + if (apzc->GetCheckerboardMagnitude(clippedBounds)) { + apzcState += "checkerboarding,"; + } + aOutData->RecordAdditionalData(viewId, apzcState); + } + } + return true; +} + +void APZCTreeManager::SendSubtreeTransformsToChromeMainThread( + const AsyncPanZoomController* aAncestor) { + RefPtr<GeckoContentController> controller = + GetContentController(mRootLayersId); + if (!controller) { + return; + } + nsTArray<MatrixMessage> messages; + bool underAncestor = (aAncestor == nullptr); + { + RecursiveMutexAutoLock lock(mTreeLock); + if (!mRootNode) { + // Event dispatched during shutdown, after ClearTree(). + // Note, mRootNode needs to be checked with mTreeLock held. + return; + } + // This formulation duplicates matrix multiplications closer + // to the root of the tree. For now, aiming for separation + // of concerns rather than minimum number of multiplications. + ForEachNode<ReverseIterator>( + mRootNode.get(), + [&](HitTestingTreeNode* aNode) { + bool atAncestor = (aAncestor && aNode->GetApzc() == aAncestor); + MOZ_ASSERT(!(underAncestor && atAncestor)); + underAncestor |= atAncestor; + if (!underAncestor) { + return; + } + LayersId layersId = aNode->GetLayersId(); + HitTestingTreeNode* parent = aNode->GetParent(); + if (!parent) { + messages.AppendElement(MatrixMessage(Some(LayerToScreenMatrix4x4()), + ScreenRect(), layersId)); + } else if (layersId != parent->GetLayersId()) { + if (mDetachedLayersIds.find(layersId) != mDetachedLayersIds.end()) { + messages.AppendElement( + MatrixMessage(Nothing(), ScreenRect(), layersId)); + } else { + messages.AppendElement(MatrixMessage( + Some(parent->GetTransformToGecko()), + parent->GetRemoteDocumentScreenRect(), layersId)); + } + } + }, + [&](HitTestingTreeNode* aNode) { + bool atAncestor = (aAncestor && aNode->GetApzc() == aAncestor); + if (atAncestor) { + MOZ_ASSERT(underAncestor); + underAncestor = false; + } + }); + } + controller->NotifyLayerTransforms(std::move(messages)); +} + +void APZCTreeManager::SetFixedLayerMargins(ScreenIntCoord aTop, + ScreenIntCoord aBottom) { + MutexAutoLock lock(mMapLock); + mCompositorFixedLayerMargins.top = aTop; + mCompositorFixedLayerMargins.bottom = aBottom; +} + +/*static*/ +LayerToParentLayerMatrix4x4 APZCTreeManager::ComputeTransformForScrollThumb( + const LayerToParentLayerMatrix4x4& aCurrentTransform, + const Matrix4x4& aScrollableContentTransform, AsyncPanZoomController* aApzc, + const FrameMetrics& aMetrics, const ScrollbarData& aScrollbarData, + bool aScrollbarIsDescendant, + AsyncTransformComponentMatrix* aOutClipTransform) { + // We only apply the transform if the scroll-target layer has non-container + // children (i.e. when it has some possibly-visible content). This is to + // avoid moving scroll-bars in the situation that only a scroll information + // layer has been built for a scroll frame, as this would result in a + // disparity between scrollbars and visible content. + if (aMetrics.IsScrollInfoLayer()) { + return LayerToParentLayerMatrix4x4{}; + } + + MOZ_RELEASE_ASSERT(aApzc); + + AsyncTransformComponentMatrix asyncTransform = + aApzc->GetCurrentAsyncTransform(AsyncPanZoomController::eForCompositing); + + // |asyncTransform| represents the amount by which we have scrolled and + // zoomed since the last paint. Because the scrollbar was sized and positioned + // based on the painted content, we need to adjust it based on asyncTransform + // so that it reflects what the user is actually seeing now. + AsyncTransformComponentMatrix scrollbarTransform; + if (*aScrollbarData.mDirection == ScrollDirection::eVertical) { + ParentLayerCoord asyncScrollY = asyncTransform._42; + const float asyncZoomY = asyncTransform._22; + + // The scroll thumb needs to be scaled in the direction of scrolling by the + // inverse of the async zoom. This is because zooming in decreases the + // fraction of the whole srollable rect that is in view. + const float yScale = 1.f / asyncZoomY; + + // Note: |metrics.GetZoom()| doesn't yet include the async zoom. + const CSSToParentLayerScale effectiveZoom(aMetrics.GetZoom().yScale * + asyncZoomY); + + if (gfxPlatform::UseDesktopZoomingScrollbars()) { + // As computed by GetCurrentAsyncTransform, asyncScrollY is + // asyncScrollY = -(GetEffectiveScrollOffset - + // mLastContentPaintMetrics.GetLayoutScrollOffset()) * + // effectiveZoom + // where GetEffectiveScrollOffset includes the visual viewport offset that + // the main thread knows about plus any async scrolling to the visual + // viewport offset that the main thread does not (yet) know about. We want + // asyncScrollY to be + // asyncScrollY = -(GetEffectiveScrollOffset - + // mLastContentPaintMetrics.GetVisualScrollOffset()) * effectiveZoom + // because the main thread positions the scrollbars at the visual viewport + // offset that it knows about. (aMetrics is mLastContentPaintMetrics) + + asyncScrollY -= ((aMetrics.GetLayoutScrollOffset() - + aMetrics.GetVisualScrollOffset()) * + effectiveZoom) + .y; + } + + // Here we convert the scrollbar thumb ratio into a true unitless ratio by + // dividing out the conversion factor from the scrollframe's parent's space + // to the scrollframe's space. + const float ratio = aScrollbarData.mThumbRatio / + (aMetrics.GetPresShellResolution() * asyncZoomY); + // The scroll thumb needs to be translated in opposite direction of the + // async scroll. This is because scrolling down, which translates the layer + // content up, should result in moving the scroll thumb down. + ParentLayerCoord yTranslation = -asyncScrollY * ratio; + + // The scroll thumb additionally needs to be translated to compensate for + // the scale applied above. The origin with respect to which the scale is + // applied is the origin of the entire scrollbar, rather than the origin of + // the scroll thumb (meaning, for a vertical scrollbar it's at the top of + // the composition bounds). This means that empty space above the thumb + // is scaled too, effectively translating the thumb. We undo that + // translation here. + // (One can think of the adjustment being done to the translation here as + // a change of basis. We have a method to help with that, + // Matrix4x4::ChangeBasis(), but it wouldn't necessarily make the code + // cleaner in this case). + const CSSCoord thumbOrigin = (aMetrics.GetVisualScrollOffset().y * ratio); + const CSSCoord thumbOriginScaled = thumbOrigin * yScale; + const CSSCoord thumbOriginDelta = thumbOriginScaled - thumbOrigin; + const ParentLayerCoord thumbOriginDeltaPL = + thumbOriginDelta * effectiveZoom; + yTranslation -= thumbOriginDeltaPL; + + scrollbarTransform.PostScale(1.f, yScale, 1.f); + scrollbarTransform.PostTranslate(0, yTranslation, 0); + } + if (*aScrollbarData.mDirection == ScrollDirection::eHorizontal) { + // See detailed comments under the eVertical case. + + ParentLayerCoord asyncScrollX = asyncTransform._41; + const float asyncZoomX = asyncTransform._11; + + const float xScale = 1.f / asyncZoomX; + + const CSSToParentLayerScale effectiveZoom(aMetrics.GetZoom().xScale * + asyncZoomX); + + if (gfxPlatform::UseDesktopZoomingScrollbars()) { + asyncScrollX -= ((aMetrics.GetLayoutScrollOffset() - + aMetrics.GetVisualScrollOffset()) * + effectiveZoom) + .x; + } + + const float ratio = aScrollbarData.mThumbRatio / + (aMetrics.GetPresShellResolution() * asyncZoomX); + ParentLayerCoord xTranslation = -asyncScrollX * ratio; + + const CSSCoord thumbOrigin = (aMetrics.GetVisualScrollOffset().x * ratio); + const CSSCoord thumbOriginScaled = thumbOrigin * xScale; + const CSSCoord thumbOriginDelta = thumbOriginScaled - thumbOrigin; + const ParentLayerCoord thumbOriginDeltaPL = + thumbOriginDelta * effectiveZoom; + xTranslation -= thumbOriginDeltaPL; + + scrollbarTransform.PostScale(xScale, 1.f, 1.f); + scrollbarTransform.PostTranslate(xTranslation, 0, 0); + } + + LayerToParentLayerMatrix4x4 transform = + aCurrentTransform * scrollbarTransform; + + AsyncTransformComponentMatrix compensation; + // If the scrollbar layer is a child of the content it is a scrollbar for, + // then we need to adjust for any async transform (including an overscroll + // transform) on the content. This needs to be cancelled out because layout + // positions and sizes the scrollbar on the assumption that there is no async + // transform, and without this adjustment the scrollbar will end up in the + // wrong place. + // + // Note that since the async transform is applied on top of the content's + // regular transform, we need to make sure to unapply the async transform in + // the same coordinate space. This requires applying the content transform + // and then unapplying it after unapplying the async transform. + if (aScrollbarIsDescendant) { + AsyncTransformComponentMatrix overscroll = + aApzc->GetOverscrollTransform(AsyncPanZoomController::eForCompositing); + Matrix4x4 asyncUntransform = + (asyncTransform * overscroll).Inverse().ToUnknownMatrix(); + const Matrix4x4& contentTransform = aScrollableContentTransform; + Matrix4x4 contentUntransform = contentTransform.Inverse(); + + compensation *= ViewAs<AsyncTransformComponentMatrix>( + contentTransform * asyncUntransform * contentUntransform); + + // Pass the total compensation out to the caller so that it can use it + // to transform clip transforms as needed. + if (aOutClipTransform) { + *aOutClipTransform = compensation; + } + } + transform = transform * compensation; + + return transform; +} + +APZSampler* APZCTreeManager::GetSampler() const { + // We should always have a sampler here, since in practice the sampler + // is destroyed at the same time that this APZCTreeMAnager instance is. + MOZ_ASSERT(mSampler); + return mSampler; +} + +void APZCTreeManager::AssertOnSamplerThread() { + GetSampler()->AssertOnSamplerThread(); +} + +APZUpdater* APZCTreeManager::GetUpdater() const { + // We should always have an updater here, since in practice the updater + // is destroyed at the same time that this APZCTreeManager instance is. + MOZ_ASSERT(mUpdater); + return mUpdater; +} + +void APZCTreeManager::AssertOnUpdaterThread() { + GetUpdater()->AssertOnUpdaterThread(); +} + +void APZCTreeManager::LockTree() { + AssertOnUpdaterThread(); + mTreeLock.Lock(); +} + +void APZCTreeManager::UnlockTree() { + AssertOnUpdaterThread(); + mTreeLock.Unlock(); +} + +void APZCTreeManager::SetDPI(float aDpiValue) { + APZThreadUtils::AssertOnControllerThread(); + mDPI = aDpiValue; +} + +float APZCTreeManager::GetDPI() const { + APZThreadUtils::AssertOnControllerThread(); + return mDPI; +} + +APZCTreeManager::FixedPositionInfo::FixedPositionInfo( + const HitTestingTreeNode* aNode) { + mFixedPositionAnimationId = aNode->GetFixedPositionAnimationId(); + mFixedPosSides = aNode->GetFixedPosSides(); + mFixedPosTarget = aNode->GetFixedPosTarget(); + mLayersId = aNode->GetLayersId(); +} + +APZCTreeManager::StickyPositionInfo::StickyPositionInfo( + const HitTestingTreeNode* aNode) { + mStickyPositionAnimationId = aNode->GetStickyPositionAnimationId(); + mFixedPosSides = aNode->GetFixedPosSides(); + mStickyPosTarget = aNode->GetStickyPosTarget(); + mLayersId = aNode->GetLayersId(); + mStickyScrollRangeInner = aNode->GetStickyScrollRangeInner(); + mStickyScrollRangeOuter = aNode->GetStickyScrollRangeOuter(); +} + +Maybe<APZHandledResult> APZCTreeManager::HitTestResult::HandledByRoot() const { + if (!mTargetApzc->IsRootContent()) { + // If the initial target is not the root, this will definitely not be + // handled by the root. (The confirmed target is either the initial + // target, or a descendant.) + return Some(APZHandledResult::HandledByContent); + } else if ((mHitResult & CompositorHitTestDispatchToContent).isEmpty()) { + // If the initial target is the root and we don't need to dispatch to + // content, the event will definitely be handled by the root. + return Some(APZHandledResult::HandledByRoot); + } + // Otherwise, we're not sure. + return Nothing(); +} + +} // namespace layers +} // namespace mozilla |