invoke.h

Go to the documentation of this file.

// SPDX-FileCopyrightText: Copyright (C) 2015 swift Project Community / Contributors
// SPDX-License-Identifier: GPL-3.0-or-later OR LicenseRef-swift-pilot-client-1
 
 
#ifndef SWIFT_MISC_INVOKE_H
#define SWIFT_MISC_INVOKE_H
 
#include <tuple>
 
#include <QMetaObject>
#include <QtGlobal>
 
#include "misc/integersequence.h"
#include "misc/promise.h"
#include "misc/typetraits.h"
 
namespace swift::misc::private_ns
{
 
    // Like invoke() but ignores the first argument if callable is not a member function. For uniform calling of
    // callables with slot semantics.
    template <typename F, typename T, typename U, size_t... Is>
    decltype(auto) invokeSlotImpl(F ptr, T *object, U tuple, std::index_sequence<Is...>, std::true_type)
    {
        Q_UNUSED(tuple); // in case the pack expansion is empty
        return (object->*ptr)(std::forward<std::tuple_element_t<Is, U>>(std::get<Is>(tuple))...);
    }
    template <typename F, typename T, typename U, size_t... Is>
    decltype(auto) invokeSlotImpl(F &&func, T *, U tuple, std::index_sequence<Is...>, std::false_type)
    {
        Q_UNUSED(tuple); // in case the pack expansion is empty
        return std::forward<F>(func)(std::forward<std::tuple_element_t<Is, U>>(std::get<Is>(tuple))...);
    }
    template <typename F, typename T, typename... Ts>
    decltype(auto) invokeSlot(F &&func, T *object, Ts &&...args)
    {
        using seq =
            MaskSequence<std::make_index_sequence<sizeof...(Ts)>, !TIsQPrivateSignal<std::decay_t<Ts>>::value...>;
        return invokeSlotImpl(std::forward<F>(func), object, std::forward_as_tuple(std::forward<Ts>(args)...), seq(),
                              std::is_member_pointer<std::decay_t<F>>());
    }
 
    // Like QMetaObject::invokeMethod but the return value is accessed through a QFuture, and extra arguments can be
    // provided.
    template <typename T, typename F, typename... Ts>
    auto invokeMethod(T *object, F &&func, Ts &&...args)
    {
        const auto invoker = [](auto &&...x) { return private_ns::invokeSlot(std::forward<decltype(x)>(x)...); };
        auto method = std::bind(invoker, std::forward<F>(func), object, std::forward<Ts>(args)...);
        CPromise<decltype(std::move(method)())> promise;
        QMetaObject::invokeMethod(
            object, [promise, method = std::move(method)]() mutable { promise.setResultFrom(std::move(method)); });
        return promise.future();
    }
 
} // namespace swift::misc::private_ns
 
#endif // SWIFT_MISC_INVOKE_H