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// 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/Node.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 {
void SlotAssignment::didAddSlot(HTMLSlotElement& slot) {
// Relevant DOM Standard:
// https://dom.spec.whatwg.org/#concept-node-insert
// 6.4: Run assign slotables for a tree with node's tree and a set containing
// each inclusive descendant of node that is a slot.
++m_slotCount;
m_needsCollectSlots = true;
if (!m_slotMap->contains(slot.name())) {
m_slotMap->add(slot.name(), &slot);
return;
}
HTMLSlotElement& oldActive = *findSlotByName(slot.name());
DCHECK_NE(oldActive, slot);
m_slotMap->add(slot.name(), &slot);
if (findSlotByName(slot.name()) == oldActive)
return;
// |oldActive| is no longer an active slot.
if (oldActive.findHostChildWithSameSlotName())
oldActive.didSlotChange(SlotChangeType::Initial);
// TODO(hayato): We should not enqeueue a slotchange event for |oldActive|
// if |oldActive| was inserted together with |slot|.
// This could happen if |oldActive| and |slot| are descendants of the inserted
// node, and |oldActive| is preceding |slot|.
}
void SlotAssignment::slotRemoved(HTMLSlotElement& slot) {
DCHECK_GT(m_slotCount, 0u);
--m_slotCount;
m_needsCollectSlots = true;
DCHECK(m_slotMap->contains(slot.name()));
HTMLSlotElement* oldActive = findSlotByName(slot.name());
m_slotMap->remove(slot.name(), &slot);
HTMLSlotElement* newActive = findSlotByName(slot.name());
if (newActive && newActive != oldActive) {
// |newActive| slot becomes an active slot.
if (newActive->findHostChildWithSameSlotName())
newActive->didSlotChange(SlotChangeType::Initial);
// TODO(hayato): Prevent a false-positive slotchange.
// This could happen if more than one slots which have the same name are
// descendants of the removed node.
}
}
bool SlotAssignment::findHostChildBySlotName(
const AtomicString& slotName) const {
// TODO(hayato): Avoid traversing children every time.
for (Node& child : NodeTraversal::childrenOf(m_owner->host())) {
if (!child.isSlotable())
continue;
if (child.slotName() == slotName)
return true;
}
return false;
}
void SlotAssignment::slotRenamed(const AtomicString& oldSlotName,
HTMLSlotElement& slot) {
// |slot| has already new name. Thus, we can not use
// slot.hasAssignedNodesSynchronously.
bool hasAssignedNodesBefore = (findSlotByName(oldSlotName) == &slot) &&
findHostChildBySlotName(oldSlotName);
m_slotMap->remove(oldSlotName, &slot);
m_slotMap->add(slot.name(), &slot);
bool hasAssignedNodesAfter = slot.hasAssignedNodesSlow();
if (hasAssignedNodesBefore || hasAssignedNodesAfter)
slot.didSlotChange(SlotChangeType::Initial);
}
void SlotAssignment::didChangeHostChildSlotName(const AtomicString& oldValue,
const AtomicString& newValue) {
if (HTMLSlotElement* slot =
findSlotByName(HTMLSlotElement::normalizeSlotName(oldValue))) {
slot->didSlotChange(SlotChangeType::Initial);
m_owner->owner()->setNeedsDistributionRecalc();
}
if (HTMLSlotElement* slot =
findSlotByName(HTMLSlotElement::normalizeSlotName(newValue))) {
slot->didSlotChange(SlotChangeType::Initial);
m_owner->owner()->setNeedsDistributionRecalc();
}
}
SlotAssignment::SlotAssignment(ShadowRoot& owner)
: m_slotMap(DocumentOrderedMap::create()),
m_owner(&owner),
m_needsCollectSlots(false),
m_slotCount(0) {
DCHECK(owner.isV1());
}
static void detachNotAssignedNode(Node& node) {
if (node.layoutObject())
node.lazyReattachIfAttached();
}
void SlotAssignment::resolveAssignment() {
for (Member<HTMLSlotElement> slot : slots())
slot->saveAndClearDistribution();
for (Node& child : NodeTraversal::childrenOf(m_owner->host())) {
if (!child.isSlotable()) {
detachNotAssignedNode(child);
continue;
}
HTMLSlotElement* slot = findSlotByName(child.slotName());
if (slot)
slot->appendAssignedNode(child);
else
detachNotAssignedNode(child);
}
}
void SlotAssignment::resolveDistribution() {
resolveAssignment();
const HeapVector<Member<HTMLSlotElement>>& slots = this->slots();
for (auto slot : slots)
slot->resolveDistributedNodes();
// 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();
(*slot)->lazyReattachDistributedNodesIfNeeded();
}
}
const HeapVector<Member<HTMLSlotElement>>& SlotAssignment::slots() {
if (m_needsCollectSlots)
collectSlots();
return m_slots;
}
HTMLSlotElement* SlotAssignment::findSlot(const Node& node) {
return node.isSlotable() ? findSlotByName(node.slotName()) : nullptr;
}
HTMLSlotElement* SlotAssignment::findSlotByName(const AtomicString& slotName) {
return m_slotMap->getSlotByName(slotName, m_owner.get());
}
void SlotAssignment::collectSlots() {
DCHECK(m_needsCollectSlots);
m_slots.clear();
m_slots.reserveCapacity(m_slotCount);
for (HTMLSlotElement& slot :
Traversal<HTMLSlotElement>::descendantsOf(*m_owner)) {
m_slots.push_back(&slot);
}
m_needsCollectSlots = false;
DCHECK_EQ(m_slots.size(), m_slotCount);
}
DEFINE_TRACE(SlotAssignment) {
visitor->trace(m_slots);
visitor->trace(m_slotMap);
visitor->trace(m_owner);
}
} // namespace blink
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