tdesktop/Telegram/SourceFiles/base/weak_unique_ptr.h

130 lines
3.5 KiB
C++

/*
This file is part of Telegram Desktop,
the official desktop version of Telegram messaging app, see https://telegram.org
Telegram Desktop is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
It is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
In addition, as a special exception, the copyright holders give permission
to link the code of portions of this program with the OpenSSL library.
Full license: https://github.com/telegramdesktop/tdesktop/blob/master/LICENSE
Copyright (c) 2014-2017 John Preston, https://desktop.telegram.org
*/
#pragma once
namespace base {
class enable_weak_from_this;
template <typename T>
class weak_unique_ptr;
class enable_weak_from_this {
public:
enable_weak_from_this() = default;
enable_weak_from_this(const enable_weak_from_this &other) noexcept {
}
enable_weak_from_this(enable_weak_from_this &&other) noexcept {
}
enable_weak_from_this &operator=(const enable_weak_from_this &other) noexcept {
return *this;
}
enable_weak_from_this &operator=(enable_weak_from_this &&other) noexcept {
return *this;
}
private:
template <typename Child>
friend class weak_unique_ptr;
std::shared_ptr<enable_weak_from_this*> getGuarded() {
if (!_guarded) {
_guarded = std::make_shared<enable_weak_from_this*>(static_cast<enable_weak_from_this*>(this));
}
return _guarded;
}
std::shared_ptr<enable_weak_from_this*> _guarded;
};
template <typename T>
class weak_unique_ptr {
public:
weak_unique_ptr() = default;
weak_unique_ptr(T *value) : _guarded(value ? value->getGuarded() : std::shared_ptr<enable_weak_from_this*>()) {
}
weak_unique_ptr(const std::unique_ptr<T> &value) : weak_unique_ptr(value.get()) {
}
weak_unique_ptr &operator=(T *value) {
_guarded = value ? value->getGuarded() : std::shared_ptr<enable_weak_from_this*>();
return *this;
}
weak_unique_ptr &operator=(const std::unique_ptr<T> &value) {
return (*this = value.get());
}
T *get() const noexcept {
if (auto shared = _guarded.lock()) {
return static_cast<T*>(*shared);
}
return nullptr;
}
explicit operator bool() const noexcept {
return !!_guarded.lock();
}
T &operator*() const noexcept {
return *get();
}
T *operator->() const noexcept {
return get();
}
private:
std::weak_ptr<enable_weak_from_this*> _guarded;
};
template <typename T>
inline bool operator==(const weak_unique_ptr<T> &pointer, std::nullptr_t) {
return (pointer.get() == nullptr);
}
template <typename T>
inline bool operator==(std::nullptr_t, const weak_unique_ptr<T> &pointer) {
return (pointer == nullptr);
}
template <typename T>
inline bool operator!=(const weak_unique_ptr<T> &pointer, std::nullptr_t) {
return !(pointer == nullptr);
}
template <typename T>
inline bool operator!=(std::nullptr_t, const weak_unique_ptr<T> &pointer) {
return !(pointer == nullptr);
}
} // namespace base
#ifdef QT_VERSION
template <typename Lambda>
inline void InvokeQueued(base::enable_weak_from_this *context, Lambda &&lambda) {
QObject proxy;
QObject::connect(&proxy, &QObject::destroyed, QCoreApplication::instance(), [guard = base::weak_unique_ptr<base::enable_weak_from_this>(context), lambda = std::forward<Lambda>(lambda)] {
if (guard) {
lambda();
}
}, Qt::QueuedConnection);
}
#endif // QT_VERSION