83 lines
		
	
	
	
		
			1.5 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			83 lines
		
	
	
	
		
			1.5 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
/*
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This file is part of Telegram Desktop,
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the official desktop application for the Telegram messaging service.
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For license and copyright information please follow this link:
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https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
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*/
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#pragma once
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#include <rpl/event_stream.h>
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namespace Data {
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template <typename FlagsType>
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using FlagsUnderlying = typename FlagsType::Type;
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template <
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	typename FlagsType,
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	FlagsUnderlying<FlagsType> kEssential = FlagsUnderlying<FlagsType>(-1)>
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class Flags {
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public:
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	using Type = FlagsType;
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	using Enum = typename Type::Enum;
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	struct Change {
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		using Type = FlagsType;
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		using Enum = typename Type::Enum;
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		Change(Type diff, Type value)
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		: diff(diff)
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		, value(value) {
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		}
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		Type diff = 0;
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		Type value = 0;
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	};
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	Flags() = default;
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	Flags(Type value) : _value(value) {
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	}
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	void set(Type which) {
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		if (auto diff = which ^ _value) {
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			_value = which;
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			updated(diff);
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		}
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	}
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	void add(Type which) {
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		if (auto diff = which & ~_value) {
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			_value |= which;
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			updated(diff);
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		}
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	}
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	void remove(Type which) {
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		if (auto diff = which & _value) {
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			_value &= ~which;
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			updated(diff);
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		}
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	}
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	auto current() const {
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		return _value;
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	}
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	auto changes() const {
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		return _changes.events();
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	}
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	auto value() const {
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		return _changes.events_starting_with({
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			Type::from_raw(kEssential),
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			_value });
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	}
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private:
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	void updated(Type diff) {
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		if ((diff &= Type::from_raw(kEssential))) {
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			_changes.fire({ diff, _value });
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		}
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	}
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	Type _value = 0;
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	rpl::event_stream<Change> _changes;
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};
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} // namespace Data
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