/*
 * Copyright (C) 2008-2019 Apple 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 APPLE 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 APPLE 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 "OpaqueJSString.h"

#include "Identifier.h"
#include "IdentifierInlines.h"
#include <wtf/MallocSpan.h>
#include <wtf/text/StringView.h>

using namespace JSC;

RefPtr<OpaqueJSString> OpaqueJSString::tryCreate(const String& string)
{
    if (string.isNull())
        return nullptr;

    return adoptRef(new OpaqueJSString(String { string }));
}

RefPtr<OpaqueJSString> OpaqueJSString::tryCreate(String&& string)
{
    if (string.isNull())
        return nullptr;

    return adoptRef(new OpaqueJSString(WTF::move(string)));
}

OpaqueJSString::~OpaqueJSString()
{
    // m_characters is put in a local here to avoid an extra atomic load.
    char16_t* characters = m_characters;
    if (!characters)
        return;

    if (!m_string.is8Bit() && m_string.span16().data() == characters)
        return;

    fastFree(characters);
}

String OpaqueJSString::string() const
{
    // Return a copy of the wrapped string, because the caller may make it an Identifier.
    return m_string.isolatedCopy();
}

Identifier OpaqueJSString::identifier(VM* vm) const
{
    if (m_string.isNull())
        return Identifier();
    if (m_string.isEmpty())
        return Identifier(Identifier::EmptyIdentifierFlag::EmptyIdentifier);
    if (m_string.is8Bit())
        return Identifier::fromString(*vm, m_string.span8());
    return Identifier::fromString(*vm, m_string.span16());
}

const char16_t* OpaqueJSString::characters() LIFETIME_BOUND
{
    // m_characters is put in a local here to avoid an extra atomic load.
    char16_t* characters = m_characters;
    if (characters)
        return characters;

    if (m_string.isNull())
        return nullptr;

    auto newCharacters = MallocSpan<char16_t>::malloc(m_string.length() * sizeof(char16_t));
    StringView { m_string }.getCharacters(newCharacters.mutableSpan());

    if (!m_characters.compare_exchange_strong(characters, newCharacters.mutableSpan().data()))
        return characters;

    return newCharacters.leakSpan().data();
}

bool OpaqueJSString::equal(const OpaqueJSString* a, const OpaqueJSString* b)
{
    if (a == b)
        return true;

    if (!a || !b)
        return false;

    return a->m_string == b->m_string;
}
