31 lines
1.1 KiB
C++
31 lines
1.1 KiB
C++
#pragma once
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#include <type_traits>
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#include "chat_messages.hpp"
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/* SFINAE compile-type checker for receive policies (as defined in chat_networking.hpp)
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* it checks whether PolicyCandidate supplies all of the following methods:
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* - void message_do_what(chat_message)
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* - void handshake_do_what(chat_message) */
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template <class PolicyCandidate, typename = void>
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struct is_valid_policy : std::false_type {};
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template <class PolicyCandidate>
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struct is_valid_policy<
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PolicyCandidate,
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typename
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std::enable_if<
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std::is_same<
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decltype(PolicyCandidate
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::message_do_what(std::declval<chat::chat_message>())),
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void
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>::value
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&&
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std::is_same<
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decltype(PolicyCandidate
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::handshake_do_what(std::declval<chat::chat_message>())),
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void
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>::value
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>::type>
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: std::true_type {}; |