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tdesktop-new-cmake/src/TelegramLibs/base/qt_signal_producer.h

82 lines
2.2 KiB
C++

// This file is part of Desktop App Toolkit,
// a set of libraries for developing nice desktop applications.
//
// For license and copyright information please follow this link:
// https://github.com/desktop-app/legal/blob/master/LEGAL
//
#pragma once
#include "base/integration.h"
namespace base {
// This method allows to create an rpl::producer from a Qt object
// and a signal with none or one reported value.
//
// QtSignalProducer(qtWindow, &QWindow::activeChanged) | rpl::start_
//
// This producer values construct a custom event loop leave point.
// This means that all postponeCall's will be invoked right after
// the value processing by the current consumer finishes.
template <typename Object, typename Signal>
auto qt_signal_producer(Object *object, Signal signal);
namespace details {
template <typename Signal>
struct qt_signal_argument;
template <typename Class, typename Return, typename Value>
struct qt_signal_argument<Return(Class::*)(Value)> {
using type = Value;
};
template <typename Class, typename Return>
struct qt_signal_argument<Return(Class::*)()> {
using type = void;
};
} // namespace details
template <typename Object, typename Signal>
auto qt_signal_producer(Object *object, Signal signal) {
using Value = typename details::qt_signal_argument<Signal>::type;
static constexpr auto NoArgument = std::is_same_v<Value, void>;
using Produced = std::conditional_t<
NoArgument,
rpl::empty_value,
std::remove_const_t<std::decay_t<Value>>>;
const auto guarded = QPointer<Object>(object);
return rpl::make_producer<Produced>([=](auto consumer) {
if (!guarded) {
return rpl::lifetime();
}
const auto connect = [&](auto &&handler) {
const auto listener = new QObject(guarded.data());
QObject::connect(
guarded,
signal,
listener,
std::forward<decltype(handler)>(handler));
const auto weak = QPointer<QObject>(listener);
return rpl::lifetime([=] {
if (weak) {
delete weak;
}
});
};
auto put = [=](const Produced &value) {
Integration::Instance().enterFromEventLoop([&] {
consumer.put_next_copy(value);
});
};
if constexpr (NoArgument) {
return connect([put = std::move(put)] { put({}); });
} else {
return connect(std::move(put));
}
});
}
} // namespace base