C++ JSCell::isString方法代码示例

void InspectorHeapAgent::getPreview(ErrorString& errorString, int heapObjectId, Inspector::Protocol::OptOutput<String>* resultString, RefPtr<Inspector::Protocol::Debugger::FunctionDetails>& functionDetails, RefPtr<Inspector::Protocol::Runtime::ObjectPreview>& objectPreview)
{
    // Prevent the cell from getting collected as we look it up.
    VM& vm = m_environment.vm();
    JSLockHolder lock(vm);
    DeferGC deferGC(vm.heap);

    unsigned heapObjectIdentifier = static_cast<unsigned>(heapObjectId);
    const Optional<HeapSnapshotNode> optionalNode = nodeForHeapObjectIdentifier(errorString, heapObjectIdentifier);
    if (!optionalNode)
        return;

    // String preview.
    JSCell* cell = optionalNode->cell;
    if (cell->isString()) {
        *resultString = cell->getString(nullptr);
        return;
    }

    // FIXME: Provide preview information for Internal Objects? CodeBlock, Executable, etc.

    Structure* structure = cell->structure(m_environment.vm());
    if (!structure) {
        errorString = ASCIILiteral("Unable to get object details - Structure");
        return;
    }

    JSGlobalObject* globalObject = structure->globalObject();
    if (!globalObject) {
        errorString = ASCIILiteral("Unable to get object details - GlobalObject");
        return;
    }

    InjectedScript injectedScript = m_injectedScriptManager.injectedScriptFor(globalObject->globalExec());
    if (injectedScript.hasNoValue()) {
        errorString = ASCIILiteral("Unable to get object details - InjectedScript");
        return;
    }

    // Function preview.
    if (cell->inherits(JSFunction::info())) {
        Deprecated::ScriptValue functionScriptValue(m_environment.vm(), JSValue(cell));
        injectedScript.functionDetails(errorString, functionScriptValue, &functionDetails);
        return;
    }

    // Object preview.
    Deprecated::ScriptValue cellScriptValue(m_environment.vm(), JSValue(cell));
    objectPreview = injectedScript.previewValue(cellScriptValue);
}

ALWAYS_INLINE void SlotVisitor::internalAppend(JSValue* slot)
{
    // This internalAppend is only intended for visits to object and array backing stores.
    // as it can change the JSValue pointed to be the argument when the original JSValue
    // is a string that contains the same contents as another string.

    StackStats::probe();
    ASSERT(slot);
    JSValue value = *slot;
    ASSERT(value);
    if (!value.isCell())
        return;

    JSCell* cell = value.asCell();
    if (!cell)
        return;

    validate(cell);

    if (m_shouldHashCons && cell->isString()) {
        JSString* string = jsCast<JSString*>(cell);
        if (string->shouldTryHashCons() && string->tryHashConsLock()) {
            UniqueStringMap::AddResult addResult = m_uniqueStrings.add(string->string().impl(), value);
            if (addResult.isNewEntry)
                string->setHashConsSingleton();
            else {
                JSValue existingJSValue = addResult.iterator->value;
                if (value != existingJSValue)
                    jsCast<JSString*>(existingJSValue.asCell())->clearHashConsSingleton();
                *slot = existingJSValue;
                string->releaseHashConsLock();
                return;
            }
            string->releaseHashConsLock();
        }
    }

    internalAppend(cell);
}

InferredType::Descriptor InferredType::Descriptor::forValue(JSValue value)
{
    if (value.isBoolean())
        return Boolean;
    if (value.isUndefinedOrNull())
        return Other;
    if (value.isInt32())
        return Int32;
    if (value.isNumber())
        return Number;
    if (value.isCell()) {
        JSCell* cell = value.asCell();
        if (cell->isString())
            return String;
        if (cell->isSymbol())
            return Symbol;
        if (cell->isObject()) {
            if (cell->structure()->transitionWatchpointSetIsStillValid())
                return Descriptor(ObjectWithStructure, cell->structure());
            return Object;
        }
    }
    return Top;
}