Replaced HTMLIdentifier with an atomized string factory function

Source/core/html/parser/HTMLIdentifier.cpp

-/*
- * Copyright (C) 2013 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 "core/html/parser/HTMLIdentifier.h"
-
-#include "HTMLNames.h"
-#include "wtf/HashMap.h"
-#include "wtf/MainThread.h"
-#include "wtf/text/StringHash.h"
-
-namespace WebCore {
-
-using namespace HTMLNames;
-
-typedef HashMap<unsigned, StringImpl*, AlreadyHashed> IdentifierTable;
-
-unsigned HTMLIdentifier::maxNameLength = 0;
-
-static IdentifierTable& identifierTable()
-{
-    DEFINE_STATIC_LOCAL(IdentifierTable, table, ());
-    ASSERT(isMainThread() || !table.isEmpty());
-    return table;
-}
-
-#ifndef NDEBUG
-bool HTMLIdentifier::isKnown(const StringImpl* string)
-{
-    const IdentifierTable& table = identifierTable();
-    return table.contains(string->hash());
-}
-#endif
-
-StringImpl* HTMLIdentifier::findIfKnown(const UChar* characters, unsigned length)
-{
-    // We don't need to try hashing if we know the string is too long.
-    if (length > maxNameLength)
-        return 0;
-    // computeHashAndMaskTop8Bits is the function StringImpl::hash() uses.
-    unsigned hash = StringHasher::computeHashAndMaskTop8Bits(characters, length);
-    const IdentifierTable& table = identifierTable();
-    ASSERT(!table.isEmpty());
-
-    IdentifierTable::const_iterator it = table.find(hash);
-    if (it == table.end())
-        return 0;
-    // It's possible to have hash collisions between arbitrary strings and
-    // known identifiers (e.g. "bvvfg" collides with "script").
-    // However ASSERTs in addNames() guard against there ever being collisions
-    // between known identifiers.
-    if (!equal(it->value, characters, length))
-        return 0;
-    return it->value;
-}
-
-const String& HTMLIdentifier::asString() const
-{
-    ASSERT(isMainThread());
-    return m_string;
-}
-
-const StringImpl* HTMLIdentifier::asStringImpl() const
-{
-    return m_string.impl();
-}
-
-void HTMLIdentifier::addNames(const QualifiedName* const* names, unsigned namesCount)
-{
-    IdentifierTable& table = identifierTable();
-    for (unsigned i = 0; i < namesCount; ++i) {
-        StringImpl* name = names[i]->localName().impl();
-        unsigned hash = name->hash();
-        IdentifierTable::AddResult addResult = table.add(hash, name);
-        maxNameLength = std::max(maxNameLength, name->length());
-        // Ensure we're using the same hashing algorithm to get and set.
-        ASSERT_UNUSED(addResult, !addResult.isNewEntry || HTMLIdentifier::findIfKnown(String(name).charactersWithNullTermination().data(), name->length()) == name);
-        // We expect some hash collisions, but only for identical strings.
-        // Since all of these names are AtomicStrings pointers should be equal.
-        // Note: If you hit this ASSERT, then we had a hash collision among
-        // HTMLNames strings, and we need to re-design how we use this hash!
-        ASSERT_UNUSED(addResult, !addResult.isNewEntry || name == addResult.iterator->value);
-    }
-}
-
-void HTMLIdentifier::init()
-{
-    ASSERT(isMainThread()); // Not technically necessary, but this is our current expected usage.
-    static bool isInitialized = false;
-    if (isInitialized)
-        return;
-    isInitialized = true;
-
-    // FIXME: We should atomize small whitespace (\n, \n\n, etc.)
-    addNames(getHTMLTags(), HTMLTagsCount);
-    addNames(getHTMLAttrs(), HTMLAttrsCount);
-}
-
-}