| /* |
| * Copyright (C) 2010 Google, 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 |
| * documentation and/or other materials provided with the distribution. |
| * |
| * THIS SOFTWARE IS PROVIDED BY GOOGLE INC. ``AS IS'' AND ANY |
| * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GOOGLE INC. OR |
| * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
| * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
| * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY |
| * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| #include "config.h" |
| #include "HTMLFormattingElementList.h" |
| |
| #ifndef NDEBUG |
| #include <stdio.h> |
| #endif |
| |
| namespace WebCore { |
| |
| // Biblically, Noah's Ark only had room for two of each animal, but in the |
| // Book of Hixie (aka http://www.whatwg.org/specs/web-apps/current-work/multipage/parsing.html#list-of-active-formatting-elements), |
| // Noah's Ark of Formatting Elements can fit three of each element. |
| static const size_t kNoahsArkCapacity = 3; |
| |
| HTMLFormattingElementList::HTMLFormattingElementList() = default; |
| |
| HTMLFormattingElementList::~HTMLFormattingElementList() = default; |
| |
| Element* HTMLFormattingElementList::closestElementInScopeWithName(const AtomicString& targetName) |
| { |
| for (unsigned i = 1; i <= m_entries.size(); ++i) { |
| const Entry& entry = m_entries[m_entries.size() - i]; |
| if (entry.isMarker()) |
| return nullptr; |
| if (entry.stackItem()->matchesHTMLTag(targetName)) |
| return &entry.element(); |
| } |
| return nullptr; |
| } |
| |
| bool HTMLFormattingElementList::contains(Element& element) |
| { |
| return !!find(element); |
| } |
| |
| auto HTMLFormattingElementList::find(Element& element) -> Entry* |
| { |
| size_t index = m_entries.reverseFind(&element); |
| if (index != notFound) { |
| // This is somewhat of a hack, and is why this method can't be const. |
| return &m_entries[index]; |
| } |
| return nullptr; |
| } |
| |
| auto HTMLFormattingElementList::bookmarkFor(Element& element) -> Bookmark |
| { |
| size_t index = m_entries.reverseFind(&element); |
| ASSERT(index != notFound); |
| return Bookmark(at(index)); |
| } |
| |
| void HTMLFormattingElementList::swapTo(Element& oldElement, Ref<HTMLStackItem>&& newItem, const Bookmark& bookmark) |
| { |
| ASSERT(contains(oldElement)); |
| ASSERT(!contains(newItem->element())); |
| if (!bookmark.hasBeenMoved()) { |
| ASSERT(&bookmark.mark().element() == &oldElement); |
| bookmark.mark().replaceElement(newItem.copyRef()); |
| return; |
| } |
| size_t index = &bookmark.mark() - &first(); |
| ASSERT_WITH_SECURITY_IMPLICATION(index < size()); |
| m_entries.insert(index + 1, WTFMove(newItem)); |
| remove(oldElement); |
| } |
| |
| void HTMLFormattingElementList::append(Ref<HTMLStackItem>&& item) |
| { |
| ensureNoahsArkCondition(item); |
| m_entries.append(WTFMove(item)); |
| } |
| |
| void HTMLFormattingElementList::remove(Element& element) |
| { |
| size_t index = m_entries.reverseFind(&element); |
| if (index != notFound) |
| m_entries.remove(index); |
| } |
| |
| void HTMLFormattingElementList::appendMarker() |
| { |
| m_entries.append(Entry::MarkerEntry); |
| } |
| |
| void HTMLFormattingElementList::clearToLastMarker() |
| { |
| // http://www.whatwg.org/specs/web-apps/current-work/multipage/parsing.html#clear-the-list-of-active-formatting-elements-up-to-the-last-marker |
| while (m_entries.size()) { |
| bool shouldStop = m_entries.last().isMarker(); |
| m_entries.removeLast(); |
| if (shouldStop) |
| break; |
| } |
| } |
| |
| void HTMLFormattingElementList::tryToEnsureNoahsArkConditionQuickly(HTMLStackItem& newItem, Vector<HTMLStackItem*>& remainingCandidates) |
| { |
| ASSERT(remainingCandidates.isEmpty()); |
| |
| if (m_entries.size() < kNoahsArkCapacity) |
| return; |
| |
| // Use a vector with inline capacity to avoid a malloc in the common case |
| // of a quickly ensuring the condition. |
| Vector<HTMLStackItem*, 10> candidates; |
| |
| size_t newItemAttributeCount = newItem.attributes().size(); |
| |
| for (size_t i = m_entries.size(); i; ) { |
| --i; |
| Entry& entry = m_entries[i]; |
| if (entry.isMarker()) |
| break; |
| |
| // Quickly reject obviously non-matching candidates. |
| RefPtr<HTMLStackItem> candidate = entry.stackItem(); |
| if (newItem.localName() != candidate->localName() || newItem.namespaceURI() != candidate->namespaceURI()) |
| continue; |
| if (candidate->attributes().size() != newItemAttributeCount) |
| continue; |
| |
| candidates.append(candidate.get()); |
| } |
| |
| if (candidates.size() < kNoahsArkCapacity) |
| return; // There's room for the new element in the ark. There's no need to copy out the remainingCandidates. |
| |
| remainingCandidates.appendVector(candidates); |
| } |
| |
| void HTMLFormattingElementList::ensureNoahsArkCondition(HTMLStackItem& newItem) |
| { |
| Vector<HTMLStackItem*> candidates; |
| tryToEnsureNoahsArkConditionQuickly(newItem, candidates); |
| if (candidates.isEmpty()) |
| return; |
| |
| // We pre-allocate and re-use this second vector to save one malloc per |
| // attribute that we verify. |
| Vector<HTMLStackItem*> remainingCandidates; |
| remainingCandidates.reserveInitialCapacity(candidates.size()); |
| |
| for (auto& attribute : newItem.attributes()) { |
| for (auto& candidate : candidates) { |
| // These properties should already have been checked by tryToEnsureNoahsArkConditionQuickly. |
| ASSERT(newItem.attributes().size() == candidate->attributes().size()); |
| ASSERT(newItem.localName() == candidate->localName() && newItem.namespaceURI() == candidate->namespaceURI()); |
| |
| auto* candidateAttribute = candidate->findAttribute(attribute.name()); |
| if (candidateAttribute && candidateAttribute->value() == attribute.value()) |
| remainingCandidates.uncheckedAppend(candidate); |
| } |
| |
| if (remainingCandidates.size() < kNoahsArkCapacity) |
| return; |
| |
| candidates.swap(remainingCandidates); |
| remainingCandidates.shrink(0); |
| } |
| |
| // Inductively, we shouldn't spin this loop very many times. It's possible, |
| // however, that we wil spin the loop more than once because of how the |
| // formatting element list gets permuted. |
| for (size_t i = kNoahsArkCapacity - 1; i < candidates.size(); ++i) |
| remove(candidates[i]->element()); |
| } |
| |
| #if ENABLE(TREE_DEBUGGING) |
| |
| void HTMLFormattingElementList::show() |
| { |
| for (unsigned i = 1; i <= m_entries.size(); ++i) { |
| const Entry& entry = m_entries[m_entries.size() - i]; |
| if (entry.isMarker()) |
| fprintf(stderr, "marker\n"); |
| else |
| entry.element().showNode(); |
| } |
| } |
| |
| #endif |
| |
| } |