C++ ExecutionEngine::newString方法代码示例

/*!
  Sets the value of this QJSValue's property with the given \a name to
  the given \a value.

  If this QJSValue is not an object, this function does nothing.

  If this QJSValue does not already have a property with name \a name,
  a new property is created.

  \sa property(), deleteProperty()
*/
void QJSValue::setProperty(const QString& name, const QJSValue& value)
{
    ExecutionEngine *engine = d->engine;
    if (!engine)
        return;
    Scope scope(engine);

    Scoped<Object> o(scope, d->value);
    if (!o)
        return;

    if (!value.d->checkEngine(o->engine())) {
        qWarning("QJSValue::setProperty(%s) failed: cannot set value created in a different engine", name.toUtf8().constData());
        return;
    }

    ScopedString s(scope, engine->newString(name));
    uint idx = s->asArrayIndex();
    if (idx < UINT_MAX) {
        setProperty(idx, value);
        return;
    }

    QV4::ExecutionContext *ctx = engine->currentContext();
    s->makeIdentifier();
    QV4::ScopedValue v(scope, value.d->getValue(engine));
    o->put(s, v);
    if (scope.hasException())
        ctx->catchException();
}

/*!
  Returns the value of this QJSValue's property with the given \a name.
  If no such property exists, an undefined QJSValue is returned.

  If the property is implemented using a getter function (i.e. has the
  PropertyGetter flag set), calling property() has side-effects on the
  script engine, since the getter function will be called (possibly
  resulting in an uncaught script exception). If an exception
  occurred, property() returns the value that was thrown (typically
  an \c{Error} object).

  \sa setProperty(), hasProperty(), QJSValueIterator
*/
QJSValue QJSValue::property(const QString& name) const
{
    ExecutionEngine *engine = d->engine;
    if (!engine)
        return QJSValue();
    QV4::Scope scope(engine);

    ScopedObject o(scope, d->value);
    if (!o)
        return QJSValue();

    ScopedString s(scope, engine->newString(name));
    uint idx = s->asArrayIndex();
    if (idx < UINT_MAX)
        return property(idx);

    s->makeIdentifier();
    QV4::ExecutionContext *ctx = engine->currentContext();
    QV4::ScopedValue result(scope);
    result = o->get(s);
    if (scope.hasException())
        result = ctx->catchException();

    return new QJSValuePrivate(engine, result);
}

/*!
  Attempts to delete this object's property of the given \a name.
  Returns true if the property was deleted, otherwise returns false.

  The behavior of this function is consistent with the JavaScript
  delete operator. In particular:

  \list
  \li Non-configurable properties cannot be deleted.
  \li This function will return true even if this object doesn't
     have a property of the given \a name (i.e., non-existent
     properties are "trivially deletable").
  \li If this object doesn't have an own property of the given
     \a name, but an object in the prototype() chain does, the
     prototype object's property is not deleted, and this function
     returns true.
  \endlist

  \sa setProperty(), hasOwnProperty()
*/
bool QJSValue::deleteProperty(const QString &name)
{
    ExecutionEngine *engine = d->engine;
    ExecutionContext *ctx = engine->currentContext();
    Scope scope(engine);
    ScopedObject o(scope, d->value.asObject());
    if (!o)
        return false;

    ScopedString s(scope, engine->newString(name));
    bool b = o->deleteProperty(s);
    if (scope.hasException())
        ctx->catchException();
    return b;
}