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// Copyright 2016 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/SlotScopedTraversal.h"
#include "core/dom/Element.h"
#include "core/dom/ElementTraversal.h"
#include "core/html/HTMLSlotElement.h"
namespace blink {
namespace {
Element* nextSkippingChildrenOfShadowHost(const Element& start,
const Element& scope) {
DCHECK(scope.assignedSlot());
if (!start.authorShadowRoot()) {
if (Element* first = ElementTraversal::firstChild(start))
return first;
}
for (const Element* current = &start; current != scope;
current = current->parentElement()) {
if (Element* nextSibling = ElementTraversal::nextSibling(*current))
return nextSibling;
}
return nullptr;
}
Element* lastWithinOrSelfSkippingChildrenOfShadowHost(const Element& scope) {
Element* current = const_cast<Element*>(&scope);
while (!current->authorShadowRoot()) {
Element* lastChild = ElementTraversal::lastChild(*current);
if (!lastChild)
break;
current = lastChild;
}
return current;
}
Element* previousSkippingChildrenOfShadowHost(const Element& start,
const Element& scope) {
DCHECK(scope.assignedSlot());
DCHECK_NE(start, &scope);
if (Element* previousSibling = ElementTraversal::previousSibling(start))
return lastWithinOrSelfSkippingChildrenOfShadowHost(*previousSibling);
return start.parentElement();
}
} // namespace
HTMLSlotElement* SlotScopedTraversal::findScopeOwnerSlot(
const Element& current) {
if (Element* nearestInclusiveAncestorAssignedToSlot =
SlotScopedTraversal::nearestInclusiveAncestorAssignedToSlot(current))
return nearestInclusiveAncestorAssignedToSlot->assignedSlot();
return nullptr;
}
Element* SlotScopedTraversal::nearestInclusiveAncestorAssignedToSlot(
const Element& current) {
Element* element = const_cast<Element*>(¤t);
for (; element; element = element->parentElement()) {
if (element->assignedSlot())
break;
}
return element;
}
Element* SlotScopedTraversal::next(const Element& current) {
Element* nearestInclusiveAncestorAssignedToSlot =
SlotScopedTraversal::nearestInclusiveAncestorAssignedToSlot(current);
DCHECK(nearestInclusiveAncestorAssignedToSlot);
// Search within children of an element which is assigned to a slot.
if (Element* next = nextSkippingChildrenOfShadowHost(
current, *nearestInclusiveAncestorAssignedToSlot))
return next;
// Seek to the next element assigned to the same slot.
HTMLSlotElement* slot =
nearestInclusiveAncestorAssignedToSlot->assignedSlot();
DCHECK(slot);
const HeapVector<Member<Node>>& assignedNodes = slot->assignedNodes();
size_t currentIndex =
assignedNodes.find(*nearestInclusiveAncestorAssignedToSlot);
DCHECK_NE(currentIndex, kNotFound);
for (++currentIndex; currentIndex < assignedNodes.size(); ++currentIndex) {
if (assignedNodes[currentIndex]->isElementNode())
return toElement(assignedNodes[currentIndex]);
}
return nullptr;
}
Element* SlotScopedTraversal::previous(const Element& current) {
Element* nearestInclusiveAncestorAssignedToSlot =
SlotScopedTraversal::nearestInclusiveAncestorAssignedToSlot(current);
DCHECK(nearestInclusiveAncestorAssignedToSlot);
if (current != nearestInclusiveAncestorAssignedToSlot) {
// Search within children of an element which is assigned to a slot.
Element* previous = previousSkippingChildrenOfShadowHost(
current, *nearestInclusiveAncestorAssignedToSlot);
DCHECK(previous);
return previous;
}
// Seek to the previous element assigned to the same slot.
const HeapVector<Member<Node>>& assignedNodes =
nearestInclusiveAncestorAssignedToSlot->assignedSlot()->assignedNodes();
size_t currentIndex =
assignedNodes.reverseFind(*nearestInclusiveAncestorAssignedToSlot);
DCHECK_NE(currentIndex, kNotFound);
for (; currentIndex > 0; --currentIndex) {
const Member<Node> assignedNode = assignedNodes[currentIndex - 1];
if (!assignedNode->isElementNode())
continue;
return lastWithinOrSelfSkippingChildrenOfShadowHost(
*toElement(assignedNode));
}
return nullptr;
}
Element* SlotScopedTraversal::firstAssignedToSlot(HTMLSlotElement& slot) {
const HeapVector<Member<Node>>& assignedNodes = slot.assignedNodes();
for (auto assignedNode : assignedNodes) {
if (assignedNode->isElementNode())
return toElement(assignedNode);
}
return nullptr;
}
Element* SlotScopedTraversal::lastAssignedToSlot(HTMLSlotElement& slot) {
const HeapVector<Member<Node>>& assignedNodes = slot.assignedNodes();
for (auto assignedNode = assignedNodes.rbegin();
assignedNode != assignedNodes.rend(); ++assignedNode) {
if (!(*assignedNode)->isElementNode())
continue;
return lastWithinOrSelfSkippingChildrenOfShadowHost(
*toElement(*assignedNode));
}
return nullptr;
}
bool SlotScopedTraversal::isSlotScoped(const Element& current) {
return SlotScopedTraversal::nearestInclusiveAncestorAssignedToSlot(current);
}
} // namespace blink
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