Make compositingState explicit

Source/core/rendering/RenderLayerCompositor.cpp

 /*
  * Copyright (C) 2009, 2010 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 306 matching lines @@
 
     IntRect visibleRect = m_containerLayer ? IntRect(IntPoint(), frameView->contentsSize()) : frameView->visibleContentRect();
     if (rootLayer->visibleRectChangeRequiresFlush(visibleRect)) {
         if (Page* page = this->page())
             page->chrome().client().scheduleCompositingLayerFlush();
     }
 }
 
 bool RenderLayerCompositor::hasAnyAdditionalCompositedLayers(const RenderLayer* rootLayer) const
 {
-    return m_compositedLayerCount > (rootLayer->isComposited() ? 1 : 0);
+    return m_compositedLayerCount > (rootLayer->compositedLayerMapping() ? 1 : 0);
 }
 
 void RenderLayerCompositor::updateCompositingRequirementsState()
 {
     if (!m_needsUpdateCompositingRequirementsState)
         return;
 
     TRACE_EVENT0("blink_rendering,comp-scroll", "RenderLayerCompositor::updateCompositingRequirementsState");
 
     m_needsUpdateCompositingRequirementsState = false;
@@ skipping 298 matching lines @@
             if (ScrollingCoordinator* scrollingCoordinator = this->scrollingCoordinator())
                 scrollingCoordinator->frameViewFixedObjectsDidChange(m_renderView->frameView());
         }
     }
 
     return layerChanged;
 }
 
 bool RenderLayerCompositor::updateLayerCompositingState(RenderLayer* layer, CompositingChangeRepaint shouldRepaint)
 {
+    CompositingState stateBeforeUpdating = layer->compositingState();
     bool layerChanged = allocateOrClearCompositedLayerMapping(layer, shouldRepaint);
 
     // See if we need content or clipping layers. Methods called here should assume
     // that the compositing state of descendant layers has not been updated yet.
     if (layer->compositedLayerMapping() && layer->compositedLayerMapping()->updateGraphicsLayerConfiguration())
         layerChanged = true;
 
-    return layerChanged;
+    // While this code is gradually evolving, this sanity check will help.
+    CompositingState stateAfterUpdating = layer->compositingState();
+    bool compositingStateChanged = (stateBeforeUpdating != stateAfterUpdating);
+    ASSERT(layerChanged == compositingStateChanged);
+
+    // Return true for either condition to avoid bugs in production code.
+    return layerChanged || compositingStateChanged;
 }
 
 void RenderLayerCompositor::repaintOnCompositingChange(RenderLayer* layer)
 {
     // If the renderer is not attached yet, no need to repaint.
     if (layer->renderer() != m_renderView && !layer->renderer()->parent())
         return;
 
     RenderLayerModelObject* repaintContainer = layer->renderer()->containerForRepaint();
     if (!repaintContainer)
         repaintContainer = m_renderView;
 
     layer->repainter().repaintIncludingNonCompositingDescendants(repaintContainer);
 }
 
 // This method assumes that layout is up-to-date, unlike repaintOnCompositingChange().
 void RenderLayerCompositor::repaintInCompositedAncestor(RenderLayer* layer, const LayoutRect& rect)
 {
     RenderLayer* compositedAncestor = layer->enclosingCompositingLayerForRepaint(false /*exclude self*/);
     if (compositedAncestor) {
-        ASSERT(compositedAncestor->compositedLayerMapping());
+        ASSERT(compositedAncestor->compositingState() == PaintsIntoOwnBacking);
 
         LayoutPoint offset;
         layer->convertToLayerCoords(compositedAncestor, offset);
 
         LayoutRect repaintRect = rect;
         repaintRect.moveBy(offset);
 
         compositedAncestor->setBackingNeedsRepaintInRect(repaintRect);
     }
 }
@@ skipping 14 matching lines @@
     return layer->calculateLayerBounds(ancestorLayer, 0, flags);
 }
 
 void RenderLayerCompositor::layerWasAdded(RenderLayer* /*parent*/, RenderLayer* /*child*/)
 {
     setCompositingLayersNeedRebuild();
 }
 
 void RenderLayerCompositor::layerWillBeRemoved(RenderLayer* parent, RenderLayer* child)
 {
-    if (!child->isComposited() || parent->renderer()->documentBeingDestroyed())
+    if (!child->compositedLayerMapping() || parent->renderer()->documentBeingDestroyed())
         return;
 
     removeViewportConstrainedLayer(child);
     repaintInCompositedAncestor(child, child->compositedLayerMapping()->compositedBounds());
 
     setCompositingParent(child, 0);
     setCompositingLayersNeedRebuild();
 }
 
 RenderLayer* RenderLayerCompositor::enclosingNonStackingClippingLayer(const RenderLayer* layer) const
@@ skipping 294 matching lines @@
         layer->reflectionLayer()->setCompositingReasons(layer->reflectionLayer()->compositingReasons() | reflectionCompositingReason);
     }
 
     // Subsequent layers in the parent's stacking context may also need to composite.
     if (childRecursionData.m_subtreeIsCompositing)
         currentRecursionData.m_subtreeIsCompositing = true;
 
     // Set the flag to say that this SC has compositing children.
     layer->setHasCompositingDescendant(childRecursionData.m_subtreeIsCompositing);
 
-
     // Turn overlap testing off for later layers if it's already off, or if we have an animating transform.
     // Note that if the layer clips its descendants, there's no reason to propagate the child animation to the parent layers. That's because
     // we know for sure the animation is contained inside the clipping rectangle, which is already added to the overlap map.
     bool isCompositedClippingLayer = canBeComposited(layer) && (reasonsToComposite & CompositingReasonClipsCompositingDescendants);
     if ((!childRecursionData.m_testingOverlap && !isCompositedClippingLayer) || isRunningAcceleratedTransformAnimation(layer->renderer()))
         currentRecursionData.m_testingOverlap = false;
 
     if (overlapMap && childRecursionData.m_compositingAncestor == layer && !layer->isRootLayer())
         overlapMap->finishCurrentOverlapTestingContext();
 
@@ skipping 19 matching lines @@
 
     descendantHas3DTransform |= anyDescendantHas3DTransform || layer->has3DTransform();
 
     if (overlapMap)
         overlapMap->geometryMap().popMappingsToAncestor(ancestorLayer);
 }
 
 void RenderLayerCompositor::setCompositingParent(RenderLayer* childLayer, RenderLayer* parentLayer)
 {
     ASSERT(!parentLayer || childLayer->ancestorCompositingLayer() == parentLayer);
-    ASSERT(childLayer->isComposited());
+    ASSERT(childLayer->compositedLayerMapping());
 
     // It's possible to be called with a parent that isn't yet composited when we're doing
     // partial updates as required by painting or hit testing. Just bail in that case;
     // we'll do a full layer update soon.
-    if (!parentLayer || !parentLayer->isComposited())
+    if (!parentLayer || !parentLayer->compositedLayerMapping())
         return;
 
     if (parentLayer) {
         GraphicsLayer* hostingLayer = parentLayer->compositedLayerMapping()->parentForSublayers();
         GraphicsLayer* hostedLayer = childLayer->compositedLayerMapping()->childForSuperlayers();
 
         hostingLayer->addChild(hostedLayer);
     } else {
         childLayer->compositedLayerMapping()->childForSuperlayers()->removeFromParent();
     }
 }
 
 void RenderLayerCompositor::removeCompositedChildren(RenderLayer* layer)
 {
-    ASSERT(layer->isComposited());
+    ASSERT(layer->compositedLayerMapping());
 
     GraphicsLayer* hostingLayer = layer->compositedLayerMapping()->parentForSublayers();
     hostingLayer->removeAllChildren();
 }
 
 bool RenderLayerCompositor::canAccelerateVideoRendering(RenderVideo* o) const
 {
     if (!m_hasAcceleratedCompositing)
         return false;
 
@@ skipping 268 matching lines @@
     return 0;
 }
 
 bool RenderLayerCompositor::parentFrameContentLayers(RenderPart* renderer)
 {
     RenderLayerCompositor* innerCompositor = frameContentsCompositor(renderer);
     if (!innerCompositor || !innerCompositor->inCompositingMode() || innerCompositor->rootLayerAttachment() != RootLayerAttachedViaEnclosingFrame)
         return false;
 
     RenderLayer* layer = renderer->layer();
-    if (!layer->isComposited())
+    if (!layer->compositedLayerMapping())
         return false;
 
     CompositedLayerMapping* compositedLayerMapping = layer->compositedLayerMapping();
     GraphicsLayer* hostingLayer = compositedLayerMapping->parentForSublayers();
     GraphicsLayer* rootLayer = innerCompositor->rootGraphicsLayer();
     if (hostingLayer->children().size() != 1 || hostingLayer->children()[0] != rootLayer) {
         hostingLayer->removeAllChildren();
         hostingLayer->addChild(rootLayer);
     }
     return true;
@@ skipping 105 matching lines @@
 
 
 void RenderLayerCompositor::repaintCompositedLayers(const IntRect* absRect)
 {
     recursiveRepaintLayer(rootRenderLayer(), absRect);
 }
 
 void RenderLayerCompositor::recursiveRepaintLayer(RenderLayer* layer, const IntRect* rect)
 {
     // FIXME: This method does not work correctly with transforms.
-    if (layer->isComposited() && !layer->compositedLayerMapping()->paintsIntoCompositedAncestor()) {
+    if (layer->compositingState() == PaintsIntoOwnBacking) {
         if (rect)
             layer->setBackingNeedsRepaintInRect(*rect);
         else
             layer->setBackingNeedsRepaint();
     }
 
 #if !ASSERT_DISABLED
     LayerListMutationDetector mutationChecker(layer);
 #endif
 
@@ skipping 72 matching lines @@
 
         detachRootLayer();
     }
 }
 
 void RenderLayerCompositor::clearMappingForRenderLayerIncludingDescendants(RenderLayer* layer)
 {
     if (!layer)
         return;
 
-    if (layer->isComposited()) {
+    if (layer->compositedLayerMapping()) {
         removeViewportConstrainedLayer(layer);
         layer->clearCompositedLayerMapping();
     }
 
     for (RenderLayer* currLayer = layer->firstChild(); currLayer; currLayer = currLayer->nextSibling())
         clearMappingForRenderLayerIncludingDescendants(currLayer);
 }
 
 void RenderLayerCompositor::clearMappingForAllRenderLayers()
 {
@@ skipping 33 matching lines @@
 bool RenderLayerCompositor::canBeComposited(const RenderLayer* layer) const
 {
     // FIXME: We disable accelerated compositing for elements in a RenderFlowThread as it doesn't work properly.
     // See http://webkit.org/b/84900 to re-enable it.
     return m_hasAcceleratedCompositing && layer->isSelfPaintingLayer() && layer->renderer()->flowThreadState() == RenderObject::NotInsideFlowThread;
 }
 
 bool RenderLayerCompositor::requiresOwnBackingStore(const RenderLayer* layer, const RenderLayer* compositingAncestorLayer) const
 {
     RenderObject* renderer = layer->renderer();
+
+    // A layer definitely needs its own backing if we cannot paint into the composited ancestor.
     if (compositingAncestorLayer
         && !(compositingAncestorLayer->compositedLayerMapping()->mainGraphicsLayer()->drawsContent()
             || compositingAncestorLayer->compositedLayerMapping()->paintsIntoCompositedAncestor()))
         return true;
 
     if (layer->isRootLayer()
         || layer->transform() // note: excludes perspective and transformStyle3D.
         || requiresCompositingForVideo(renderer)
         || requiresCompositingForCanvas(renderer)
         || requiresCompositingForPlugin(renderer)
@@ skipping 70 matching lines @@
     if (requiresCompositingForOutOfFlowClipping(layer))
         directReasons |= CompositingReasonOutOfFlowClipping;
 
     return directReasons;
 }
 
 CompositingReasons RenderLayerCompositor::reasonsForCompositing(const RenderLayer* layer) const
 {
     CompositingReasons reasons = CompositingReasonNone;
 
-    if (!layer || !layer->isComposited())
+    if (!layer || !layer->compositedLayerMapping())
         return reasons;
 
     return layer->compositingReasons();
 }
 
 #if !LOG_DISABLED
 const char* RenderLayerCompositor::logReasonsForCompositing(const RenderLayer* layer)
 {
     CompositingReasons reasons = reasonsForCompositing(layer);
 
@@ skipping 70 matching lines @@
 }
 #endif
 
 // Return true if the given layer has some ancestor in the RenderLayer hierarchy that clips,
 // up to the enclosing compositing ancestor. This is required because compositing layers are parented
 // according to the z-order hierarchy, yet clipping goes down the renderer hierarchy.
 // Thus, a RenderLayer can be clipped by a RenderLayer that is an ancestor in the renderer hierarchy,
 // but a sibling in the z-order hierarchy.
 bool RenderLayerCompositor::clippedByAncestor(const RenderLayer* layer) const
 {
-    if (!layer->isComposited() || !layer->parent())
+    if (!layer->compositedLayerMapping() || !layer->parent())
         return false;
 
     const RenderLayer* compositingAncestor = layer->ancestorCompositingLayer();
     if (!compositingAncestor)
         return false;
 
     // If the compositingAncestor clips, that will be taken care of by clipsCompositingDescendants(),
     // so we only care about clipping between its first child that is our ancestor (the computeClipRoot),
     // and layer.
     const RenderLayer* computeClipRoot = 0;
@@ skipping 88 matching lines @@
 
     bool composite = renderer->isEmbeddedObject() && toRenderEmbeddedObject(renderer)->allowsAcceleratedCompositing();
     if (!composite)
         return false;
 
     m_reevaluateCompositingAfterLayout = true;
 
     RenderWidget* pluginRenderer = toRenderWidget(renderer);
     // If we can't reliably know the size of the plugin yet, don't change compositing state.
     if (pluginRenderer->needsLayout())
-        return pluginRenderer->hasLayer() && pluginRenderer->layer()->isComposited();
+        return pluginRenderer->hasLayer() && pluginRenderer->layer()->compositedLayerMapping();
 
     // Don't go into compositing mode if height or width are zero, or size is 1x1.
     IntRect contentBox = pixelSnappedIntRect(pluginRenderer->contentBoxRect());
     return contentBox.height() * contentBox.width() > 1;
 }
 
 bool RenderLayerCompositor::requiresCompositingForFrame(RenderObject* renderer) const
 {
     if (!renderer->isRenderPart())
         return false;
 
     RenderPart* frameRenderer = toRenderPart(renderer);
 
     if (!frameRenderer->requiresAcceleratedCompositing())
         return false;
 
     m_reevaluateCompositingAfterLayout = true;
 
     RenderLayerCompositor* innerCompositor = frameContentsCompositor(frameRenderer);
     if (!innerCompositor)
         return false;
 
     // If we can't reliably know the size of the iframe yet, don't change compositing state.
     if (renderer->needsLayout())
-        return frameRenderer->hasLayer() && frameRenderer->layer()->isComposited();
+        return frameRenderer->hasLayer() && frameRenderer->layer()->compositedLayerMapping();
 
     // Don't go into compositing mode if height or width are zero.
     IntRect contentBox = pixelSnappedIntRect(frameRenderer->contentBoxRect());
     return contentBox.height() * contentBox.width() > 0;
 }
 
 bool RenderLayerCompositor::requiresCompositingForBackfaceVisibilityHidden(RenderObject* renderer) const
 {
     return canRender3DTransforms() && renderer->style()->backfaceVisibility() == BackfaceVisibilityHidden;
 }
@@ skipping 154 matching lines @@
 
     if (!hasScrollableAncestor) {
         if (viewportConstrainedNotCompositedReason)
             *viewportConstrainedNotCompositedReason = RenderLayer::NotCompositedForUnscrollableAncestors;
         return false;
     }
 
     // Subsequent tests depend on layout. If we can't tell now, just keep things the way they are until layout is done.
     if (!m_inPostLayoutUpdate) {
         m_reevaluateCompositingAfterLayout = true;
-        return layer->isComposited();
+        return layer->compositedLayerMapping();
     }
 
     bool paintsContent = layer->isVisuallyNonEmpty() || layer->hasVisibleDescendant();
     if (!paintsContent) {
         if (viewportConstrainedNotCompositedReason)
             *viewportConstrainedNotCompositedReason = RenderLayer::NotCompositedForNoVisibleContent;
         return false;
     }
 
     // Fixed position elements that are invisible in the current view don't get their own layer.
@@ skipping 90 matching lines @@
     return supportsFixedRootBackgroundCompositing() && m_renderView->rootBackgroundIsEntirelyFixed();
 }
 
 GraphicsLayer* RenderLayerCompositor::fixedRootBackgroundLayer() const
 {
     // Get the fixed root background from the RenderView layer's compositedLayerMapping.
     RenderLayer* viewLayer = m_renderView->layer();
     if (!viewLayer)
         return 0;
 
-    if (viewLayer->isComposited() && viewLayer->compositedLayerMapping()->backgroundLayerPaintsFixedRootBackground())
+    if (viewLayer->compositingState() == PaintsIntoOwnBacking && viewLayer->compositedLayerMapping()->backgroundLayerPaintsFixedRootBackground())
         return viewLayer->compositedLayerMapping()->backgroundLayer();
 
     return 0;
 }
 
 static void resetTrackedRepaintRectsRecursive(GraphicsLayer* graphicsLayer)
 {
     if (!graphicsLayer)
         return;
 
@@ skipping 392 matching lines @@
 
 static bool isRootmostFixedOrStickyLayer(RenderLayer* layer)
 {
     if (layer->renderer()->isStickyPositioned())
         return true;
 
     if (layer->renderer()->style()->position() != FixedPosition)
         return false;
 
     for (RenderLayer* stackingContainer = layer->ancestorStackingContainer(); stackingContainer; stackingContainer = stackingContainer->ancestorStackingContainer()) {
-        if (stackingContainer->isComposited() && stackingContainer->renderer()->style()->position() == FixedPosition)
+        if (stackingContainer->compositedLayerMapping() && stackingContainer->renderer()->style()->position() == FixedPosition)
             return false;
     }
 
     return true;
 }
 
 void RenderLayerCompositor::updateViewportConstraintStatus(RenderLayer* layer)
 {
     if (isRootmostFixedOrStickyLayer(layer))
         addViewportConstrainedLayer(layer);
     else
         removeViewportConstrainedLayer(layer);
 }
 
 void RenderLayerCompositor::addViewportConstrainedLayer(RenderLayer* layer)
 {
     m_viewportConstrainedLayers.add(layer);
 }
 
 void RenderLayerCompositor::removeViewportConstrainedLayer(RenderLayer* layer)
 {
     if (!m_viewportConstrainedLayers.contains(layer))
         return;
 
     m_viewportConstrainedLayers.remove(layer);
 }
 
 FixedPositionViewportConstraints RenderLayerCompositor::computeFixedViewportConstraints(RenderLayer* layer) const
 {
-    ASSERT(layer->isComposited());
+    ASSERT(layer->compositedLayerMapping());
 
     FrameView* frameView = m_renderView->frameView();
     LayoutRect viewportRect = frameView->viewportConstrainedVisibleContentRect();
 
     FixedPositionViewportConstraints constraints;
 
     GraphicsLayer* graphicsLayer = layer->compositedLayerMapping()->mainGraphicsLayer();
 
     constraints.setLayerPositionAtLastLayout(graphicsLayer->position());
     constraints.setViewportRectAtLastLayout(viewportRect);
@@ skipping 17 matching lines @@
 
     // If top and bottom are auto, use top.
     if (style->top().isAuto() && style->bottom().isAuto())
         constraints.addAnchorEdge(ViewportConstraints::AnchorEdgeTop);
 
     return constraints;
 }
 
 StickyPositionViewportConstraints RenderLayerCompositor::computeStickyViewportConstraints(RenderLayer* layer) const
 {
-    ASSERT(layer->isComposited());
+    ASSERT(layer->compositedLayerMapping());
 
     FrameView* frameView = m_renderView->frameView();
     LayoutRect viewportRect = frameView->viewportConstrainedVisibleContentRect();
 
     StickyPositionViewportConstraints constraints;
 
     RenderBoxModelObject* renderer = toRenderBoxModelObject(layer->renderer());
 
     renderer->computeStickyPositionConstraints(constraints, viewportRect);
 
@@ skipping 49 matching lines @@
     } else if (graphicsLayer == m_scrollLayer.get()) {
         name = "Frame Scrolling Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
 } // namespace WebCore