Source/JavaScriptCore/runtime/SmallStrings.cpp

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#include "config.h"
#include "SmallStrings.h"

#include "JSCJSValueInlines.h"
#include <wtf/text/StringImpl.h>

namespace JSC {

SmallStrings::SmallStrings()
{
    static_assert(singleCharacterStringCount == sizeof(m_singleCharacterStrings) / sizeof(m_singleCharacterStrings[0]), "characters count is in sync with class usage");

    for (unsigned i = 0; i < singleCharacterStringCount; ++i)
        m_singleCharacterStrings[i] = nullptr;
}

void SmallStrings::initializeCommonStrings(VM& vm)
{
    ASSERT(!m_emptyString);
    m_emptyString = JSString::createEmptyString(vm);
    ASSERT(m_needsToBeVisited);

    for (unsigned i = 0; i < singleCharacterStringCount; ++i) {
        ASSERT(!m_singleCharacterStrings[i]);
        const LChar string[] = { static_cast<LChar>(i) };
        m_singleCharacterStrings[i] = JSString::createHasOtherOwner(vm, AtomStringImpl::add(string, 1).releaseNonNull());
        ASSERT(m_needsToBeVisited);
    }

#define JSC_COMMON_STRINGS_ATTRIBUTE_INITIALIZE(name) initialize(&vm, m_##name, #name ## _s);
    JSC_COMMON_STRINGS_EACH_NAME(JSC_COMMON_STRINGS_ATTRIBUTE_INITIALIZE)
#undef JSC_COMMON_STRINGS_ATTRIBUTE_INITIALIZE
    initialize(&vm, m_objectStringStart, "[object "_s);
    initialize(&vm, m_nullObjectString, "[object Null]"_s);
    initialize(&vm, m_undefinedObjectString, "[object Undefined]"_s);
    initialize(&vm, m_boundPrefixString, "bound "_s);
    initialize(&vm, m_notEqualString, "not-equal"_s);
    initialize(&vm, m_timedOutString, "timed-out"_s);
    initialize(&vm, m_okString, "ok"_s);
    initialize(&vm, m_sentinelString, "$"_s);

    setIsInitialized(true);
}

template<typename Visitor>
void SmallStrings::visitStrongReferences(Visitor& visitor)
{
    m_needsToBeVisited = false;
    visitor.appendUnbarriered(m_emptyString);
    for (unsigned i = 0; i <= maxSingleCharacterString; ++i)
        visitor.appendUnbarriered(m_singleCharacterStrings[i]);
#define JSC_COMMON_STRINGS_ATTRIBUTE_VISIT(name) visitor.appendUnbarriered(m_##name);
    JSC_COMMON_STRINGS_EACH_NAME(JSC_COMMON_STRINGS_ATTRIBUTE_VISIT)
#undef JSC_COMMON_STRINGS_ATTRIBUTE_VISIT
    visitor.appendUnbarriered(m_objectStringStart);
    visitor.appendUnbarriered(m_nullObjectString);
    visitor.appendUnbarriered(m_undefinedObjectString);
    visitor.appendUnbarriered(m_boundPrefixString);
    visitor.appendUnbarriered(m_notEqualString);
    visitor.appendUnbarriered(m_timedOutString);
    visitor.appendUnbarriered(m_okString);
    visitor.appendUnbarriered(m_sentinelString);
}

template void SmallStrings::visitStrongReferences(AbstractSlotVisitor&);
template void SmallStrings::visitStrongReferences(SlotVisitor&);

SmallStrings::~SmallStrings()
{
}

Ref<AtomStringImpl> SmallStrings::singleCharacterStringRep(unsigned char character)
{
    if (LIKELY(m_isInitialized))
        return *static_cast<AtomStringImpl*>(const_cast<StringImpl*>(m_singleCharacterStrings[character]->tryGetValueImpl()));
    const LChar string[] = { static_cast<LChar>(character) };
    return AtomStringImpl::add(string, 1).releaseNonNull();
}

void SmallStrings::initialize(VM* vm, JSString*& string, ASCIILiteral value)
{
    string = JSString::create(*vm, AtomStringImpl::add(value));
    ASSERT(m_needsToBeVisited);
}

} // namespace JSC