Move hit testing out of RenderLayer into RenderBox.

sky/engine/core/rendering/RenderLayer.cpp

Index: sky/engine/core/rendering/RenderLayer.cpp
diff --git a/sky/engine/core/rendering/RenderLayer.cpp b/sky/engine/core/rendering/RenderLayer.cpp
index 37a3337f4332d393b09f653929a3195b6351c9c9..ed1bfc539649da1b32820049e0e325aa6b68114b 100644
--- a/sky/engine/core/rendering/RenderLayer.cpp
+++ b/sky/engine/core/rendering/RenderLayer.cpp
@@ -788,281 +788,6 @@ void RenderLayer::restoreClip(GraphicsContext* context, const LayoutRect& paintD
     context->restore();
 }
 
-Node* RenderLayer::enclosingElement() const
-{
-    for (RenderObject* r = renderer(); r; r = r->parent()) {
-        if (Node* e = r->node())
-            return e;
-    }
-    ASSERT_NOT_REACHED();
-    return 0;
-}
-
-// Compute the z-offset of the point in the transformState.
-// This is effectively projecting a ray normal to the plane of ancestor, finding where that
-// ray intersects target, and computing the z delta between those two points.
-static double computeZOffset(const HitTestingTransformState& transformState)
-{
-    // We got an affine transform, so no z-offset
-    if (transformState.m_accumulatedTransform.isAffine())
-        return 0;
-
-    // Flatten the point into the target plane
-    FloatPoint targetPoint = transformState.mappedPoint();
-
-    // Now map the point back through the transform, which computes Z.
-    FloatPoint3D backmappedPoint = transformState.m_accumulatedTransform.mapPoint(FloatPoint3D(targetPoint));
-    return backmappedPoint.z();
-}
-
-PassRefPtr<HitTestingTransformState> RenderLayer::createLocalTransformState(RenderLayer* rootLayer, RenderLayer* containerLayer,
-                                        const LayoutRect& hitTestRect, const HitTestLocation& hitTestLocation,
-                                        const HitTestingTransformState* containerTransformState,
-                                        const LayoutPoint& translationOffset) const
-{
-    RefPtr<HitTestingTransformState> transformState;
-    LayoutPoint offset;
-    if (containerTransformState) {
-        // If we're already computing transform state, then it's relative to the container (which we know is non-null).
-        transformState = HitTestingTransformState::create(*containerTransformState);
-        convertToLayerCoords(containerLayer, offset);
-    } else {
-        // If this is the first time we need to make transform state, then base it off of hitTestLocation,
-        // which is relative to rootLayer.
-        transformState = HitTestingTransformState::create(hitTestLocation.transformedPoint(), hitTestLocation.transformedRect(), FloatQuad(hitTestRect));
-        convertToLayerCoords(rootLayer, offset);
-    }
-    offset.moveBy(translationOffset);
-
-    RenderObject* containerRenderer = containerLayer ? containerLayer->renderer() : 0;
-    if (renderer()->shouldUseTransformFromContainer(containerRenderer)) {
-        TransformationMatrix containerTransform;
-        renderer()->getTransformFromContainer(containerRenderer, toLayoutSize(offset), containerTransform);
-        transformState->applyTransform(containerTransform, HitTestingTransformState::AccumulateTransform);
-    } else {
-        transformState->translate(offset.x(), offset.y(), HitTestingTransformState::AccumulateTransform);
-    }
-
-    return transformState;
-}
-
-
-static bool isHitCandidate(bool canDepthSort, double* zOffset, const HitTestingTransformState* transformState)
-{
-    // The hit layer is depth-sorting with other layers, so just say that it was hit.
-    if (canDepthSort)
-        return true;
-
-    // We need to look at z-depth to decide if this layer was hit.
-    if (zOffset) {
-        ASSERT(transformState);
-        // This is actually computing our z, but that's OK because the hitLayer is coplanar with us.
-        double childZOffset = computeZOffset(*transformState);
-        if (childZOffset > *zOffset) {
-            *zOffset = childZOffset;
-            return true;
-        }
-        return false;
-    }
-
-    return true;
-}
-
-// hitTestLocation and hitTestRect are relative to rootLayer.
-// A 'flattening' layer is one preserves3D() == false.
-// transformState.m_accumulatedTransform holds the transform from the containing flattening layer.
-// transformState.m_lastPlanarPoint is the hitTestLocation in the plane of the containing flattening layer.
-// transformState.m_lastPlanarQuad is the hitTestRect as a quad in the plane of the containing flattening layer.
-//
-// If zOffset is non-null (which indicates that the caller wants z offset information),
-//  *zOffset on return is the z offset of the hit point relative to the containing flattening layer.
-bool RenderLayer::hitTestLayer(RenderLayer* rootLayer, RenderLayer* containerLayer, const HitTestRequest& request, HitTestResult& result,
-                                       const LayoutRect& hitTestRect, const HitTestLocation& hitTestLocation,
-                                       const HitTestingTransformState* transformState, double* zOffset)
-{
-    if (!isSelfPaintingLayer() && !hasSelfPaintingLayerDescendant())
-        return 0;
-
-    // The natural thing would be to keep HitTestingTransformState on the stack, but it's big, so we heap-allocate.
-    RefPtr<HitTestingTransformState> localTransformState;
-
-    LayoutRect localHitTestRect = hitTestRect;
-    HitTestLocation localHitTestLocation = hitTestLocation;
-
-    // We need transform state for the first time, or to offset the container state, or to accumulate the new transform.
-    if (transform() || transformState || m_has3DTransformedDescendant || preserves3D())
-        localTransformState = createLocalTransformState(rootLayer, containerLayer, localHitTestRect, localHitTestLocation, transformState);
-
-    // Apply a transform if we have one.
-    if (transform()) {
-        // Make sure the parent's clip rects have been calculated.
-        if (parent()) {
-            ClipRect clipRect = clipper().backgroundClipRect(ClipRectsContext(rootLayer, RootRelativeClipRects));
-            // Go ahead and test the enclosing clip now.
-            if (!clipRect.intersects(localHitTestLocation))
-                return 0;
-        }
-
-        // If the transform can't be inverted, then don't hit test this layer at all.
-        if (!localTransformState->m_accumulatedTransform.isInvertible())
-            return 0;
-
-        // Compute the point and the hit test rect in the coords of this layer by using the values
-        // from the transformState, which store the point and quad in the coords of the last flattened
-        // layer, and the accumulated transform which lets up map through preserve-3d layers.
-        //
-        // We can't just map hitTestLocation and hitTestRect because they may have been flattened (losing z)
-        // by our container.
-        FloatPoint localPoint = localTransformState->mappedPoint();
-        FloatQuad localPointQuad = localTransformState->mappedQuad();
-        localHitTestRect = localTransformState->boundsOfMappedArea();
-        if (localHitTestLocation.isRectBasedTest())
-            localHitTestLocation = HitTestLocation(localPoint, localPointQuad);
-        else
-            localHitTestLocation = HitTestLocation(localPoint);
-
-        // Now do a hit test with the root layer shifted to be us.
-        rootLayer = this;
-    }
-
-    // Ensure our lists and 3d status are up-to-date.
-    m_stackingNode->updateLayerListsIfNeeded();
-    update3DTransformedDescendantStatus();
-
-    // Check for hit test on backface if backface-visibility is 'hidden'
-    if (localTransformState && renderer()->style()->backfaceVisibility() == BackfaceVisibilityHidden) {
-        TransformationMatrix invertedMatrix = localTransformState->m_accumulatedTransform.inverse();
-        // If the z-vector of the matrix is negative, the back is facing towards the viewer.
-        if (invertedMatrix.m33() < 0)
-            return 0;
-    }
-
-    RefPtr<HitTestingTransformState> unflattenedTransformState = localTransformState;
-    if (localTransformState && !preserves3D()) {
-        // Keep a copy of the pre-flattening state, for computing z-offsets for the container
-        unflattenedTransformState = HitTestingTransformState::create(*localTransformState);
-        // This layer is flattening, so flatten the state passed to descendants.
-        localTransformState->flatten();
-    }
-
-    // The following are used for keeping track of the z-depth of the hit point of 3d-transformed
-    // descendants.
-    double localZOffset = -std::numeric_limits<double>::infinity();
-    double* zOffsetForDescendantsPtr = 0;
-    double* zOffsetForContentsPtr = 0;
-
-    bool depthSortDescendants = false;
-    if (preserves3D()) {
-        depthSortDescendants = true;
-        // Our layers can depth-test with our container, so share the z depth pointer with the container, if it passed one down.
-        zOffsetForDescendantsPtr = zOffset ? zOffset : &localZOffset;
-        zOffsetForContentsPtr = zOffset ? zOffset : &localZOffset;
-    } else if (zOffset) {
-        zOffsetForDescendantsPtr = 0;
-        // Container needs us to give back a z offset for the hit layer.
-        zOffsetForContentsPtr = zOffset;
-    }
-
-    // Begin by walking our list of positive layers from highest z-index down to the lowest z-index.
-    bool hitLayer = hitTestChildren(PositiveZOrderChildren, rootLayer, request, result, localHitTestRect, localHitTestLocation,
-                                    localTransformState.get(), zOffsetForDescendantsPtr, zOffset, unflattenedTransformState.get(), depthSortDescendants);
-    if (hitLayer && !depthSortDescendants)
-        return true;
-
-    // Now check our overflow objects.
-    hitLayer = hitTestChildren(NormalFlowChildren, rootLayer, request, result, localHitTestRect, localHitTestLocation,
-                               localTransformState.get(), zOffsetForDescendantsPtr, zOffset, unflattenedTransformState.get(), depthSortDescendants);
-    if (hitLayer && !depthSortDescendants)
-        return true;
-
-    LayoutRect layerBounds;
-    // FIXME(sky): Remove foregroundRect. It's unused.
-    ClipRect contentRect, foregroundRect;
-    ClipRectsContext clipRectsContext(rootLayer, RootRelativeClipRects);
-    clipper().calculateRects(clipRectsContext, localHitTestRect, layerBounds, contentRect, foregroundRect);
-
-    // Next we want to see if the mouse pos is inside the child RenderObjects of the layer.
-    if (isSelfPaintingLayer() && contentRect.intersects(localHitTestLocation)) {
-        // Hit test with a temporary HitTestResult, because we only want to commit to 'result' if we know we're frontmost.
-        HitTestResult tempResult(result.hitTestLocation());
-        if (hitTestContents(request, tempResult, layerBounds, localHitTestLocation)
-            && isHitCandidate(false, zOffsetForContentsPtr, unflattenedTransformState.get())) {
-            if (result.isRectBasedTest())
-                result.append(tempResult);
-            else
-                result = tempResult;
-            if (!depthSortDescendants)
-                return true;
-            // Foreground can depth-sort with descendant layers, so keep this as a candidate.
-            hitLayer = true;
-        } else if (result.isRectBasedTest()) {
-            result.append(tempResult);
-        }
-    }
-
-    return hitLayer;
-}
-
-bool RenderLayer::hitTestContents(const HitTestRequest& request, HitTestResult& result, const LayoutRect& layerBounds, const HitTestLocation& hitTestLocation) const
-{
-    ASSERT(isSelfPaintingLayer() || hasSelfPaintingLayerDescendant());
-
-    if (!renderer()->hitTest(request, result, hitTestLocation, toLayoutPoint(layerBounds.location() - renderBoxLocation()))) {
-        // It's wrong to set innerNode, but then claim that you didn't hit anything, unless it is
-        // a rect-based test.
-        ASSERT(!result.innerNode() || (result.isRectBasedTest() && result.rectBasedTestResult().size()));
-        return false;
-    }
-
-    // For positioned generated content, we might still not have a
-    // node by the time we get to the layer level, since none of
-    // the content in the layer has an element. So just walk up
-    // the tree.
-    if (!result.innerNode() || !result.innerNonSharedNode()) {
-        Node* e = enclosingElement();
-        if (!result.innerNode())
-            result.setInnerNode(e);
-        if (!result.innerNonSharedNode())
-            result.setInnerNonSharedNode(e);
-    }
-
-    return true;
-}
-
-bool RenderLayer::hitTestChildren(ChildrenIteration childrentoVisit, RenderLayer* rootLayer,
-    const HitTestRequest& request, HitTestResult& result,
-    const LayoutRect& hitTestRect, const HitTestLocation& hitTestLocation,
-    const HitTestingTransformState* transformState,
-    double* zOffsetForDescendants, double* zOffset,
-    const HitTestingTransformState* unflattenedTransformState,
-    bool depthSortDescendants)
-{
-    if (!hasSelfPaintingLayerDescendant())
-        return 0;
-
-    bool hitLayer = false;
-    RenderLayerStackingNodeReverseIterator iterator(*m_stackingNode, childrentoVisit);
-    while (RenderLayerStackingNode* child = iterator.next()) {
-        RenderLayer* childLayer = child->layer();
-        HitTestResult tempResult(result.hitTestLocation());
-        hitLayer |= childLayer->hitTestLayer(rootLayer, this, request, tempResult, hitTestRect, hitTestLocation, transformState, zOffsetForDescendants);
-
-        // If it a rect-based test, we can safely append the temporary result since it might had hit
-        // nodes but not necesserily had hitLayer set.
-        if (result.isRectBasedTest())
-            result.append(tempResult);
-
-        if (hitLayer && isHitCandidate(depthSortDescendants, zOffset, unflattenedTransformState)) {
-            if (!result.isRectBasedTest())
-                result = tempResult;
-            if (!depthSortDescendants)
-                break;
-        }
-    }
-
-    return hitLayer;
-}
-
 bool RenderLayer::intersectsDamageRect(const LayoutRect& layerBounds, const LayoutRect& damageRect, const RenderLayer* rootLayer, const LayoutPoint* offsetFromRoot) const
 {
     // Always examine the canvas and the root.