Simplify slot assignments

third_party/WebKit/Source/core/dom/shadow/SlotAssignment.cpp

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/dom/shadow/SlotAssignment.h"
 
 #include "core/HTMLNames.h"
 #include "core/dom/ElementTraversal.h"
 #include "core/dom/NodeTraversal.h"
 #include "core/dom/shadow/ElementShadow.h"
 #include "core/dom/shadow/InsertionPoint.h"
 #include "core/dom/shadow/ShadowRoot.h"
 #include "core/html/HTMLSlotElement.h"
 
 namespace blink {
 
 HTMLSlotElement* SlotAssignment::assignedSlotFor(const Node& node) const
 {
     return m_assignment.get(const_cast<Node*>(&node));
 }
 
 static void detachNotAssignedNode(Node& node)
 {
     if (node.layoutObject())
         node.lazyReattachIfAttached();
 }
 
-inline static bool isDefaultSlotName(const AtomicString& name)
-{
-    return name.isNull() || name.isEmpty();
-}
-
 void SlotAssignment::resolveAssignment(ShadowRoot& shadowRoot)
 {
     m_assignment.clear();
 
     using Name2Slot = HeapHashMap<AtomicString, Member<HTMLSlotElement>>;
     Name2Slot name2slot;
-    HTMLSlotElement* defaultSlot = nullptr;
 
     const HeapVector<Member<HTMLSlotElement>>& slots = shadowRoot.descendantSlots();
 
     for (Member<HTMLSlotElement> slot : slots) {
         slot->willUpdateDistribution();
-        AtomicString name = slot->fastGetAttribute(HTMLNames::nameAttr);
-        if (isDefaultSlotName(name)) {
-            if (!defaultSlot)
-                defaultSlot = slot.get();
-        } else {
-            name2slot.add(name, slot.get());
-        }
+        name2slot.add(slot->name(), slot.get());
     }
 
     for (Node& child : NodeTraversal::childrenOf(*shadowRoot.host())) {
-        if (child.isElementNode()) {
-            if (isActiveInsertionPoint(child)) {
-                // TODO(hayato): Support re-distribution across v0 and v1 shadow trees
-                detachNotAssignedNode(child);
-                continue;
-            }
-            AtomicString slotName = toElement(child).fastGetAttribute(HTMLNames::slotAttr);
-            if (isDefaultSlotName(slotName)) {
-                if (defaultSlot)
-                    assign(child, *defaultSlot);
-                else
-                    detachNotAssignedNode(child);
-            } else {
-                HTMLSlotElement* slot = name2slot.get(slotName);
-                if (slot)
-                    assign(child, *slot);
-                else
-                    detachNotAssignedNode(child);
-            }
-        } else if (defaultSlot && child.isTextNode()) {
-            assign(child, *defaultSlot);
-        } else {
+        if (child.isElementNode() && isActiveInsertionPoint(child)) {
+            // TODO(hayato): Support re-distribution across v0 and v1 shadow trees
             detachNotAssignedNode(child);
+            continue;
         }
+        if (!child.slottable()) {
+            detachNotAssignedNode(child);
+            continue;
+        }
+        AtomicString slotName = child.slotName();
+        HTMLSlotElement* slot = name2slot.get(slotName);
+        if (slot)
+            assign(child, *slot);
+        else
+            detachNotAssignedNode(child);
     }
 
     // Update each slot's distribution in reverse tree order so that a child slot is visited before its parent slot.
     for (auto slot = slots.rbegin(); slot != slots.rend(); ++slot)
         (*slot)->updateDistributedNodesWithFallback();
     for (const auto& slot : slots)
         slot->didUpdateDistribution();
 }
 
 void SlotAssignment::assign(Node& hostChild, HTMLSlotElement& slot)
 {
     DCHECK(hostChild.isSlotAssignable());
     m_assignment.add(&hostChild, &slot);
     slot.appendAssignedNode(hostChild);
     if (isHTMLSlotElement(hostChild))
         slot.appendDistributedNodesFrom(toHTMLSlotElement(hostChild));
     else
         slot.appendDistributedNode(hostChild);
     if (slot.isChildOfV1ShadowHost())
         slot.parentElementShadow()->setNeedsDistributionRecalc();
 }
 
 DEFINE_TRACE(SlotAssignment)
 {
     visitor->trace(m_assignment);
 }
 
 } // namespace blink