ultralight::dom::LockableHolder

Whether or not the DOM API can hold an object through H (ignoring const and references), ie. More...

#include <Ultralight/dom/Holders.h>

Concept definition

template<typename H>
concept LockableHolder = requires { typename HolderTraits<std::remove_cvref_t<H>>::element_type; }
    && (ultralight::detail::HolderHasLock<std::remove_cvref_t<H>>
        || ultralight::detail::HolderHasGet<std::remove_cvref_t<H>>)

Detailed Description

Whether or not the DOM API can hold an object through H (ignoring const and references), ie.

ultralight::HolderTraits is specialized for it.

Some DOM calls can take a smart pointer to your object instead of a reference. These are the listener overloads that take an object and a member function (eg, Element::addEventListener() and Element::On()) and the data-binding API (ultralight::dom::data):

auto player = std::make_shared<Player>();
button.addEventListener("click", std::weak_ptr(player), &Player::OnClick);

RefPtr, WeakPtr, std::shared_ptr, std::weak_ptr, and std::unique_ptr work without any setup:

• An owning pointer keeps your object alive (RefPtr, std::shared_ptr, or a std::unique_ptr you move in) for as long as the listener (or binding) exists.
• A weak pointer doesn't keep it alive (WeakPtr or std::weak_ptr). The library locks it for each call and skips each call that comes after your object is destroyed. A data binding then keeps the values it last published.

To use your engine's own smart pointer, specialize ultralight::HolderTraits for it (see <Ultralight/HolderTraits.h>).