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| -rw-r--r-- | gfx/layers/apz/src/HitTestingTreeNode.h | 270 |
1 files changed, 270 insertions, 0 deletions
diff --git a/gfx/layers/apz/src/HitTestingTreeNode.h b/gfx/layers/apz/src/HitTestingTreeNode.h new file mode 100644 index 0000000000..ed20f9f561 --- /dev/null +++ b/gfx/layers/apz/src/HitTestingTreeNode.h @@ -0,0 +1,270 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=8 sts=2 et sw=2 tw=80: */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#ifndef mozilla_layers_HitTestingTreeNode_h +#define mozilla_layers_HitTestingTreeNode_h + +#include "mozilla/gfx/CompositorHitTestInfo.h" +#include "mozilla/gfx/Matrix.h" // for Matrix4x4 +#include "mozilla/layers/LayersTypes.h" // for EventRegions +#include "mozilla/layers/ScrollableLayerGuid.h" // for ScrollableLayerGuid +#include "mozilla/layers/ScrollbarData.h" // for ScrollbarData +#include "mozilla/Maybe.h" // for Maybe +#include "mozilla/RecursiveMutex.h" // for RecursiveMutexAutoLock +#include "mozilla/RefPtr.h" // for nsRefPtr +namespace mozilla { +namespace layers { + +class AsyncDragMetrics; +class AsyncPanZoomController; + +/** + * This class represents a node in a tree that is used by the APZCTreeManager + * to do hit testing. The tree is roughly a copy of the layer tree, but will + * contain multiple nodes in cases where the layer has multiple FrameMetrics. + * In other words, the structure of this tree should be identical to the + * WebRenderScrollDataWrapper tree (see documentation in + * WebRenderScrollDataWrapper.h). + * + * Not all HitTestingTreeNode instances will have an APZC associated with them; + * only HitTestingTreeNodes that correspond to layers with scrollable metrics + * have APZCs. + * Multiple HitTestingTreeNode instances may share the same underlying APZC + * instance if the layers they represent share the same scrollable metrics (i.e. + * are part of the same animated geometry root). If this happens, exactly one of + * the HitTestingTreeNode instances will be designated as the "primary holder" + * of the APZC. When this primary holder is destroyed, it will destroy the APZC + * along with it; in contrast, destroying non-primary-holder nodes will not + * destroy the APZC. + * Code should not make assumptions about which of the nodes will be the + * primary holder, only that that there will be exactly one for each APZC in + * the tree. + * + * The reason this tree exists at all is so that we can do hit-testing on the + * thread that we receive input on (referred to the as the controller thread in + * APZ terminology), which may be different from the compositor thread. + * Accessing the compositor layer tree can only be done on the compositor + * thread, and so it is simpler to make a copy of the hit-testing related + * properties into a separate tree. + * + * The tree pointers on the node (mLastChild, etc.) can only be manipulated + * while holding the APZ tree lock. Any code that wishes to use a + * HitTestingTreeNode outside of holding the tree lock should do so by using + * the HitTestingTreeNodeAutoLock wrapper, which prevents the node from + * being recycled (and also holds a RefPtr to the node to prevent it from + * getting freed). + */ +class HitTestingTreeNode { + NS_INLINE_DECL_THREADSAFE_REFCOUNTING(HitTestingTreeNode); + + private: + ~HitTestingTreeNode(); + + public: + HitTestingTreeNode(AsyncPanZoomController* aApzc, bool aIsPrimaryHolder, + LayersId aLayersId); + void RecycleWith(const RecursiveMutexAutoLock& aProofOfTreeLock, + AsyncPanZoomController* aApzc, LayersId aLayersId); + // Clears the tree pointers on the node, thereby breaking RefPtr cycles. This + // can trigger free'ing of this and other HitTestingTreeNode instances. + void Destroy(); + + // Returns true if and only if the node is available for recycling as part + // of a hit-testing tree update. Note that this node can have Destroy() called + // on it whether or not it is recyclable. + bool IsRecyclable(const RecursiveMutexAutoLock& aProofOfTreeLock); + + /* Tree construction methods */ + + void SetLastChild(HitTestingTreeNode* aChild); + void SetPrevSibling(HitTestingTreeNode* aSibling); + void MakeRoot(); + + /* Tree walking methods. GetFirstChild is O(n) in the number of children. The + * other tree walking methods are all O(1). */ + + HitTestingTreeNode* GetFirstChild() const; + HitTestingTreeNode* GetLastChild() const; + HitTestingTreeNode* GetPrevSibling() const; + HitTestingTreeNode* GetParent() const; + + bool IsAncestorOf(const HitTestingTreeNode* aOther) const; + + /* APZC related methods */ + + AsyncPanZoomController* GetApzc() const; + AsyncPanZoomController* GetNearestContainingApzc() const; + bool IsPrimaryHolder() const; + LayersId GetLayersId() const; + + /* Hit test related methods */ + + void SetHitTestData( + const LayerIntRegion& aVisibleRegion, + const LayerIntSize& aRemoteDocumentSize, + const CSSTransformMatrix& aTransform, + const EventRegionsOverride& aOverride, + const Maybe<ScrollableLayerGuid::ViewID>& aAsyncZoomContainerId); + + /* Scrollbar info */ + + void SetScrollbarData(const Maybe<uint64_t>& aScrollbarAnimationId, + const ScrollbarData& aScrollbarData); + bool MatchesScrollDragMetrics(const AsyncDragMetrics& aDragMetrics, + LayersId aLayersId) const; + bool IsScrollbarNode() const; // Scroll thumb or scrollbar container layer. + bool IsScrollbarContainerNode() const; // Scrollbar container layer. + // This can only be called if IsScrollbarNode() is true + ScrollDirection GetScrollbarDirection() const; + bool IsScrollThumbNode() const; // Scroll thumb container layer. + ScrollableLayerGuid::ViewID GetScrollTargetId() const; + const ScrollbarData& GetScrollbarData() const; + Maybe<uint64_t> GetScrollbarAnimationId() const; + + /* Fixed pos info */ + + void SetFixedPosData(ScrollableLayerGuid::ViewID aFixedPosTarget, + SideBits aFixedPosSides, + const Maybe<uint64_t>& aFixedPositionAnimationId); + ScrollableLayerGuid::ViewID GetFixedPosTarget() const; + SideBits GetFixedPosSides() const; + Maybe<uint64_t> GetFixedPositionAnimationId() const; + + /* Sticky pos info */ + void SetStickyPosData(ScrollableLayerGuid::ViewID aStickyPosTarget, + const LayerRectAbsolute& aScrollRangeOuter, + const LayerRectAbsolute& aScrollRangeInner, + const Maybe<uint64_t>& aStickyPositionAnimationId); + ScrollableLayerGuid::ViewID GetStickyPosTarget() const; + const LayerRectAbsolute& GetStickyScrollRangeOuter() const; + const LayerRectAbsolute& GetStickyScrollRangeInner() const; + Maybe<uint64_t> GetStickyPositionAnimationId() const; + + /* Returns the mOverride flag. */ + EventRegionsOverride GetEventRegionsOverride() const; + const CSSTransformMatrix& GetTransform() const; + /* This is similar to APZCTreeManager::GetApzcToGeckoTransform but without + * the async bits. It's used on the main-thread for transforming coordinates + * across a BrowserParent/BrowserChild interface.*/ + LayerToScreenMatrix4x4 GetTransformToGecko() const; + const LayerIntRegion& GetVisibleRegion() const; + + /* Returns the screen coordinate rectangle of remote iframe corresponding to + * this node. The rectangle is the result of clipped by ancestor async + * scrolling. */ + ScreenRect GetRemoteDocumentScreenRect() const; + + Maybe<ScrollableLayerGuid::ViewID> GetAsyncZoomContainerId() const; + + /* Debug helpers */ + void Dump(const char* aPrefix = "") const; + + private: + friend class HitTestingTreeNodeAutoLock; + // Functions that are private but called from HitTestingTreeNodeAutoLock + void Lock(const RecursiveMutexAutoLock& aProofOfTreeLock); + void Unlock(const RecursiveMutexAutoLock& aProofOfTreeLock); + + void SetApzcParent(AsyncPanZoomController* aApzc); + + RefPtr<HitTestingTreeNode> mLastChild; + RefPtr<HitTestingTreeNode> mPrevSibling; + RefPtr<HitTestingTreeNode> mParent; + + RefPtr<AsyncPanZoomController> mApzc; + bool mIsPrimaryApzcHolder; + int mLockCount; + + LayersId mLayersId; + + // This is only set if WebRender is enabled, and only for HTTNs + // where IsScrollThumbNode() returns true. It holds the animation id that we + // use to move the thumb node to reflect async scrolling. + Maybe<uint64_t> mScrollbarAnimationId; + + // This is set for scrollbar Container and Thumb layers. + ScrollbarData mScrollbarData; + + // This is only set if WebRender is enabled. It holds the animation id that + // we use to adjust fixed position content for the toolbar. + Maybe<uint64_t> mFixedPositionAnimationId; + + ScrollableLayerGuid::ViewID mFixedPosTarget; + SideBits mFixedPosSides; + + ScrollableLayerGuid::ViewID mStickyPosTarget; + LayerRectAbsolute mStickyScrollRangeOuter; + LayerRectAbsolute mStickyScrollRangeInner; + // This is only set if WebRender is enabled. It holds the animation id that + // we use to adjust sticky position content for the toolbar. + Maybe<uint64_t> mStickyPositionAnimationId; + + LayerIntRegion mVisibleRegion; + + /* The size of remote iframe on the corresponding layer coordinate. + * It's empty if this node is not for remote iframe. */ + LayerIntSize mRemoteDocumentSize; + + /* This is the transform from layer L. This does NOT include any async + * transforms. */ + CSSTransformMatrix mTransform; + + /* If the layer is the async zoom container layer then this will hold the id. + */ + Maybe<ScrollableLayerGuid::ViewID> mAsyncZoomContainerId; + + /* Indicates whether or not the event regions on this node need to be + * overridden in a certain way. */ + EventRegionsOverride mOverride; +}; + +/** + * A class that allows safe usage of a HitTestingTreeNode outside of the APZ + * tree lock. In general, this class should be Initialize()'d inside the tree + * lock (enforced by the proof-of-lock to Initialize), and then can be returned + * to a scope outside the tree lock and used safely. Upon destruction or + * Clear() being called, it unlocks the underlying node at which point it can + * be recycled or freed. + */ +class HitTestingTreeNodeAutoLock final { + public: + HitTestingTreeNodeAutoLock(); + ~HitTestingTreeNodeAutoLock(); + // Make it move-only. Note that the default implementations of the move + // constructor and assignment operator are correct: they'll call the + // move constructor of mNode, which will null out mNode on the moved-from + // object, and Clear() will early-exit when the moved-from object's + // destructor is called. + HitTestingTreeNodeAutoLock(HitTestingTreeNodeAutoLock&&) = default; + HitTestingTreeNodeAutoLock& operator=(HitTestingTreeNodeAutoLock&&) = default; + + void Initialize(const RecursiveMutexAutoLock& aProofOfTreeLock, + already_AddRefed<HitTestingTreeNode> aNode, + RecursiveMutex& aTreeMutex); + void Clear(); + + // Convenience operators to simplify the using code. + explicit operator bool() const { return !!mNode; } + bool operator!() const { return !mNode; } + HitTestingTreeNode* operator->() const { return mNode.get(); } + + // Allow getting back a raw pointer to the node, but only inside the scope + // of the tree lock. The caller is responsible for ensuring that they do not + // use the raw pointer outside that scope. + HitTestingTreeNode* Get( + mozilla::RecursiveMutexAutoLock& aProofOfTreeLock) const { + return mNode.get(); + } + + private: + RefPtr<HitTestingTreeNode> mNode; + RecursiveMutex* mTreeMutex; +}; + +} // namespace layers +} // namespace mozilla + +#endif // mozilla_layers_HitTestingTreeNode_h |