C++ JSObject::prototype方法代码示例

// from khtml/ecma/debugger/debugwindow.cpp
static QString exceptionToString(KJS::ExecState* exec, KJS::JSValue* exceptionObj)
{
    QString exceptionMsg = valueToString(exceptionObj);

    // Since we purposefully bypass toString, we need to figure out
    // string serialization ourselves.
    //### might be easier to export class info for ErrorInstance ---

    KJS::JSObject* valueObj = exceptionObj->getObject();
    KJS::JSValue*  protoObj = valueObj ? valueObj->prototype() : 0;

    bool exception   = false;
    bool syntaxError = false;
    if (protoObj == exec->lexicalInterpreter()->builtinSyntaxErrorPrototype())
    {
        exception   = true;
        syntaxError = true;
    }

    if (protoObj == exec->lexicalInterpreter()->builtinErrorPrototype()          ||
        protoObj == exec->lexicalInterpreter()->builtinEvalErrorPrototype()      ||
        protoObj == exec->lexicalInterpreter()->builtinReferenceErrorPrototype() ||
        protoObj == exec->lexicalInterpreter()->builtinRangeErrorPrototype()     ||
        protoObj == exec->lexicalInterpreter()->builtinTypeErrorPrototype()      ||
        protoObj == exec->lexicalInterpreter()->builtinURIErrorPrototype())
    {
        exception = true;
    }

    if (!exception)
        return exceptionMsg;

    // Clear exceptions temporarily so we can get/call a few things.
    // We memorize the old exception first, of course. Note that
    // This is not always the same as exceptionObj since we may be
    //  asked to translate a non-active exception
    KJS::JSValue* oldExceptionObj = exec->exception();
    exec->clearException();

    // We want to serialize the syntax errors ourselves, to provide the line number.
    // The URL is in "sourceURL" and the line is in "line"
    // ### TODO: Perhaps we want to use 'sourceId' in case of eval contexts.
    if (syntaxError)
    {
        KJS::JSValue* lineValue = valueObj->get(exec, "line");
        KJS::JSValue* urlValue  = valueObj->get(exec, "sourceURL");

        int      line = lineValue->toNumber(exec);
        QString  url  = urlValue->toString(exec).qstring();
        exceptionMsg = i18n("Parse error at %1 line %2",
                            url, line + 1);
    }
    else
    {
        // ### it's still not 100% safe to call toString here, even on
        // native exception objects, since someone might have changed the toString property
        // of the exception prototype, but I'll punt on this case for now.
        exceptionMsg = exceptionObj->toString(exec).qstring();
    }
    exec->setException(oldExceptionObj);
    return exceptionMsg;
}