Subtree caching implementation in blink-core

Source/core/layout/LayoutObject.h

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 99 matching lines @@
     LayoutRect bounds;
     bool draggable;
 };
 
 typedef WTF::HashMap<const DeprecatedPaintLayer*, Vector<LayoutRect>> LayerHitTestRects;
 
 #ifndef NDEBUG
 const int showTreeCharacterOffset = 39;
 #endif
 
+class NonLayoutObjectDisplayItemClientWrapper : public DisplayItemClientWrapper {

[pdr., 2015/08/20 22:45:05]

I'd prefer not to add this, but it may be needed. Don't non-layout objects also
need a function like setNeedsRepaint()?

[Xianzhu, 2015/08/21 00:31:38]

In next steps, I'll try to decouple setting of repaint flags from
invalidateDisplayItemClient(), then whether the display item client is a
LayoutObject will be no longer matter.

[trchen, 2015/08/21 00:37:29]

It doesn't seem that it is used in this CL. Shall we add it in another CL when
it is actually used?

[Xianzhu, 2015/08/21 04:54:51]

Currently non-LayoutObject clients depend on
DisplayItemList::validlyCachedClients for paint invalidation. Thoughts here:
https://codereview.chromium.org/1294233004/diff/100001/Source/platform/graphi...
It's used by invalidateDisplayItemClient() to distinguish non-LayoutObject and
LayoutObject clients.

+public:
+    template <typename T>
+    NonLayoutObjectDisplayItemClientWrapper(const T& client)
+        : DisplayItemClientWrapper(client) { }
+
+    NonLayoutObjectDisplayItemClientWrapper(const LayoutObject&) = delete;
+};
+
 // Base class for all layout tree objects.
 class CORE_EXPORT LayoutObject : public ImageResourceClient {
     friend class LayoutBlock;
     friend class LayoutBlockFlow;
     friend class DeprecatedPaintLayerReflectionInfo; // For setParent
     friend class DeprecatedPaintLayerScrollableArea; // For setParent.
     friend class LayoutObjectChildList;
     WTF_MAKE_NONCOPYABLE(LayoutObject);
 public:
     // Anonymous objects should pass the document as their node, and they will then automatically be
@@ skipping 720 matching lines @@
 
     // Returns the rect bounds needed to invalidate the paint of this object, in the coordinate space of the layoutObject backing of |paintInvalidationContainer|
     LayoutRect boundsRectForPaintInvalidation(const LayoutBoxModelObject* paintInvalidationContainer, const PaintInvalidationState* = nullptr) const;
 
     // Actually do the paint invalidate of rect r for this object which has been computed in the coordinate space
     // of the GraphicsLayer backing of |paintInvalidationContainer|. Note that this coordinaten space is not the same
     // as the local coordinate space of |paintInvalidationContainer| in the presence of layer squashing.
     void invalidatePaintUsingContainer(const LayoutBoxModelObject& paintInvalidationContainer, const LayoutRect&, PaintInvalidationReason) const;
 
     // Invalidate the paint of a specific subrectangle within a given object. The rect |r| is in the object's coordinate space.
-    void invalidatePaintRectangle(const LayoutRect&) const;
-    void invalidatePaintRectangleNotInvalidatingDisplayItemClients(const LayoutRect& r) const { invalidatePaintRectangleInternal(r); }
+    void invalidatePaintRectangle(const LayoutRect&);
+    void invalidatePaintRectangleNotInvalidatingDisplayItemClients(const LayoutRect& r) { invalidatePaintRectangleInternal(r); }
 
     // Walk the tree after layout issuing paint invalidations for layoutObjects that have changed or moved, updating bounds that have changed, and clearing paint invalidation state.
     virtual void invalidateTreeIfNeeded(PaintInvalidationState&);
 
     virtual void invalidatePaintForOverflow();
     void invalidatePaintForOverflowIfNeeded();
 
     void invalidatePaintIncludingNonCompositingDescendants();
     void setShouldDoFullPaintInvalidationIncludingNonCompositingDescendants();
 
@@ skipping 172 matching lines @@
     {
         return layoutDidGetCalledSinceLastFrame() || mayNeedPaintInvalidation() || shouldDoFullPaintInvalidation() || shouldInvalidateSelection();
     }
 
     virtual bool supportsPaintInvalidationStateCachedOffsets() const { return !hasTransformRelatedProperty() && !hasReflection() && !style()->isFlippedBlocksWritingMode(); }
 
     virtual LayoutRect viewRect() const;
 
     DisplayItemClient displayItemClient() const { return toDisplayItemClient(this); }
 
-    void invalidateDisplayItemClient(const DisplayItemClientWrapper&) const;
-    void invalidateDisplayItemClientForNonCompositingDescendants() const { invalidateDisplayItemClientForNonCompositingDescendantsOf(*this); }
+    void invalidateDisplayItemClient(const NonLayoutObjectDisplayItemClientWrapper&);
+    void invalidateDisplayItemClient(LayoutObject&);
+    void invalidateDisplayItemClientForNonCompositingDescendants() { invalidateDisplayItemClientForNonCompositingDescendantsOf(*this); }
     // A normal object should use invalidateDisplayItemClientForNonCompositingDescendants()
     // to invalidate its descendants which are painted on the same backing. However, for
     // an object (e.g. LayoutScrollbarPart, custom scroll corner, custom resizer) which is
     // not hooked up in the layout tree and not able to find its paint backing, it should
     // let its owning layout object call the following function.
     // FIXME: should we hook up scrollbar parts in the layout tree? crbug.com/484263.
-    void invalidateDisplayItemClientForNonCompositingDescendantsOf(const LayoutObject&) const;
+    void invalidateDisplayItemClientForNonCompositingDescendantsOf(LayoutObject&);
+
+    bool selfNeedsRepaint() const { return m_bitfields.selfNeedsRepaint(); }

[pdr., 2015/08/20 22:45:05]

Can you add a comment here explaining this a bit?

// Slimming paint v2 tracks whether a LayoutObject is invalid instead of using
invalidation rects.
// For more information, see:
https://docs.google.com/document/d/1FTqk3MwUAS1qLJsnA9zgfDbeqAQBdLYC4GJ9jpN-x...

[Xianzhu, 2015/08/21 00:31:38]

Done.

+    void setNeedsRepaint();
+    bool childNeedsRepaint() const { return m_bitfields.childNeedsRepaint(); }
+    bool shouldCheckForRepaint() const { return selfNeedsRepaint() || childNeedsRepaint(); }
+
+    // Returns true if all repaint flags of the subtree are cleared.
+    bool clearRepaintFlagsRecursively();

[trchen, 2015/08/21 00:37:29]

In this CL it seems the return value will always be true. Is it reserved for
future use?

[Xianzhu, 2015/08/21 04:54:51]

Will remove the return value first.

[Xianzhu, 2015/08/21 05:52:45]

Done.

 
 protected:
     enum LayoutObjectType {
         LayoutObjectBr,
         LayoutObjectCanvas,
         LayoutObjectFieldset,
         LayoutObjectCounter,
         LayoutObjectDetailsMarker,
         LayoutObjectEmbeddedObject,
         LayoutObjectFileUploadControl,
@@ skipping 109 matching lines @@
     }
 #endif
 
     virtual void invalidatePaintOfSubtreesIfNeeded(PaintInvalidationState& childPaintInvalidationState);
     virtual PaintInvalidationReason invalidatePaintIfNeeded(PaintInvalidationState&, const LayoutBoxModelObject& paintInvalidationContainer);
 
     // When this object is invalidated for paint, this method is called to invalidate any DisplayItemClients
     // owned by this object, including the object itself, LayoutText/LayoutInline line boxes, etc.,
     // not including children which will be invalidated normally during invalidateTreeIfNeeded() and
     // parts which are invalidated separately (e.g. scrollbars).
-    virtual void invalidateDisplayItemClients(const LayoutBoxModelObject& paintInvalidationContainer) const;
+    virtual void invalidateDisplayItemClients(const LayoutBoxModelObject& paintInvalidationContainer);
+
+    virtual bool clearRepaintFlagsOfSubtrees();
 
     void setIsSlowRepaintObject(bool);
 
 private:
     const LayoutRect& previousPaintInvalidationRect() const { return m_previousPaintInvalidationRect; }
 
     // Adjusts a paint invalidation rect in the space of |m_previousPaintInvalidationRect| and |m_previousPositionFromPaintInvalidationBacking|
     // to be in the space of the |paintInvalidationContainer|,
     // if needed. They can be different only if |paintInvalidationContainer| is a composited scroller.
     void adjustInvalidationRectForCompositedScrolling(LayoutRect&, const LayoutBoxModelObject& paintInvalidationContainer) const;
@@ skipping 10 matching lines @@
     void updateFillImages(const FillLayer* oldLayers, const FillLayer& newLayers);
 
     void setNeedsOverflowRecalcAfterStyleChange();
 
     // FIXME: This should be 'markContaingBoxChainForOverflowRecalc when we make LayoutBox
     // recomputeOverflow-capable. crbug.com/437012 and crbug.com/434700.
     inline void markContainingBlocksForOverflowRecalc();
 
     inline void markContainerChainForPaintInvalidation();
 
+    void markContainerChainForRepaint();
+    void setChildNeedsRepaint();
+
     inline void invalidateSelectionIfNeeded(const LayoutBoxModelObject&, PaintInvalidationReason);
 
     inline void invalidateContainerPreferredLogicalWidths();
 
     void clearMayNeedPaintInvalidation();
 
     void setLayoutDidGetCalledSinceLastFrame();
     void clearLayoutDidGetCalledSinceLastFrame() { m_bitfields.setLayoutDidGetCalledSinceLastFrame(false); }
 
     void invalidatePaintIncludingNonCompositingDescendantsInternal(const LayoutBoxModelObject& repaintContainer);
@@ skipping 15 matching lines @@
     void removeShapeImageClient(ShapeValue*);
 
 #if ENABLE(ASSERT)
     void checkBlockPositionedObjectsNeedLayout();
 #endif
 
     bool isTextOrSVGChild() const { return isText() || (isSVG() && !isSVGRoot()); }
 
     static bool isAllowedToModifyLayoutTreeStructure(Document&);
 
-    const LayoutBoxModelObject* invalidatePaintRectangleInternal(const LayoutRect&) const;
+    const LayoutBoxModelObject* invalidatePaintRectangleInternal(const LayoutRect&);
+
+    void invalidateDisplayItemClientInternal(const DisplayItemClientWrapper&);
 
     RefPtr<ComputedStyle> m_style;
 
     // Oilpan: raw pointer back to the owning Node is considered safe.
     GC_PLUGIN_IGNORE("http://crbug.com/509911")
     Node* m_node;
 
     LayoutObject* m_parent;
     LayoutObject* m_previous;
     LayoutObject* m_next;
@@ skipping 52 matching lines @@
             , m_layoutDidGetCalledSinceLastFrame(false)
             , m_hasPendingResourceUpdate(false)
             , m_isInsideFlowThread(false)
             , m_subtreeChangeListenerRegistered(false)
             , m_notifiedOfSubtreeChange(false)
             , m_consumesSubtreeChangeNotification(false)
             , m_childrenInline(false)
             , m_alwaysCreateLineBoxesForLayoutInline(false)
             , m_lastBoxDecorationBackgroundObscured(false)
             , m_isSlowRepaintObject(false)
+            , m_selfNeedsRepaint(false)
+            , m_childNeedsRepaint(false)
             , m_positionedState(IsStaticallyPositioned)
             , m_selectionState(SelectionNone)
             , m_boxDecorationBackgroundState(NoBoxDecorationBackground)
             , m_fullPaintInvalidationReason(PaintInvalidationNone)
         {
         }
 
-        // 32 bits have been used in the first word, and 16 in the second.
+        // 32 bits have been used in the first word, and 18 in the second.
         ADD_BOOLEAN_BITFIELD(selfNeedsLayout, SelfNeedsLayout);
         ADD_BOOLEAN_BITFIELD(shouldInvalidateOverflowForPaint, ShouldInvalidateOverflowForPaint);
         ADD_BOOLEAN_BITFIELD(mayNeedPaintInvalidation, MayNeedPaintInvalidation);
         ADD_BOOLEAN_BITFIELD(shouldInvalidateSelection, ShouldInvalidateSelection);
         ADD_BOOLEAN_BITFIELD(neededLayoutBecauseOfChildren, NeededLayoutBecauseOfChildren);
         ADD_BOOLEAN_BITFIELD(needsPositionedMovementLayout, NeedsPositionedMovementLayout);
         ADD_BOOLEAN_BITFIELD(normalChildNeedsLayout, NormalChildNeedsLayout);
         ADD_BOOLEAN_BITFIELD(posChildNeedsLayout, PosChildNeedsLayout);
         ADD_BOOLEAN_BITFIELD(needsSimplifiedNormalFlowLayout, NeedsSimplifiedNormalFlowLayout);
         ADD_BOOLEAN_BITFIELD(preferredLogicalWidthsDirty, PreferredLogicalWidthsDirty);
@@ skipping 32 matching lines @@
         ADD_BOOLEAN_BITFIELD(childrenInline, ChildrenInline);
 
         // from LayoutInline
         ADD_BOOLEAN_BITFIELD(alwaysCreateLineBoxesForLayoutInline, AlwaysCreateLineBoxesForLayoutInline);
 
         // For slimming-paint.
         ADD_BOOLEAN_BITFIELD(lastBoxDecorationBackgroundObscured, LastBoxDecorationBackgroundObscured);
 
         ADD_BOOLEAN_BITFIELD(isSlowRepaintObject, IsSlowRepaintObject);
 
+        // For slimming-paint v2.
+        // TODO(wangxianzhu): Combine repaint flags with paint invalidation flags when we remove
+        // old paint invalidation code.
+        ADD_BOOLEAN_BITFIELD(selfNeedsRepaint, SelfNeedsRepaint);
+        ADD_BOOLEAN_BITFIELD(childNeedsRepaint, ChildNeedsRepaint);
+
     private:
         unsigned m_positionedState : 2; // PositionedState
         unsigned m_selectionState : 3; // SelectionState
         unsigned m_boxDecorationBackgroundState : 2; // BoxDecorationBackgroundState
         unsigned m_fullPaintInvalidationReason : 5; // PaintInvalidationReason
 
     public:
         bool isOutOfFlowPositioned() const { return m_positionedState == IsOutOfFlowPositioned; }
         bool isRelPositioned() const { return m_positionedState == IsRelativelyPositioned; }
         bool isStickyPositioned() const { return m_positionedState == IsStickyPositioned; }
@@ skipping 269 matching lines @@
 void showTree(const blink::LayoutObject*);
 void showLineTree(const blink::LayoutObject*);
 void showLayoutTree(const blink::LayoutObject* object1);
 // We don't make object2 an optional parameter so that showLayoutTree
 // can be called from gdb easily.
 void showLayoutTree(const blink::LayoutObject* object1, const blink::LayoutObject* object2);
 
 #endif
 
 #endif // LayoutObject_h