tdesktop/Telegram/SourceFiles/data/data_flags.h

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/*
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
#include <rpl/event_stream.h>
namespace Data {
template <typename FlagsType>
using FlagsUnderlying = typename FlagsType::Type;
template <
typename FlagsType,
FlagsUnderlying<FlagsType> kEssential = FlagsUnderlying<FlagsType>(-1)>
class Flags {
public:
using Type = FlagsType;
using Enum = typename Type::Enum;
struct Change {
using Type = FlagsType;
using Enum = typename Type::Enum;
Change(Type diff, Type value)
: diff(diff)
, value(value) {
}
Type diff = 0;
Type value = 0;
};
Flags() = default;
Flags(Type value) : _value(value) {
}
void set(Type which) {
if (auto diff = which ^ _value) {
_value = which;
updated(diff);
}
}
void add(Type which) {
if (auto diff = which & ~_value) {
_value |= which;
updated(diff);
}
}
void remove(Type which) {
if (auto diff = which & _value) {
_value &= ~which;
updated(diff);
}
}
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auto current() const {
return _value;
}
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auto changes() const {
return _changes.events();
}
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auto value() const {
return _changes.events_starting_with({
Type::from_raw(kEssential),
_value });
}
private:
void updated(Type diff) {
if ((diff &= Type::from_raw(kEssential))) {
_changes.fire({ diff, _value });
}
}
Type _value = 0;
rpl::event_stream<Change> _changes;
};
} // namespace Data