mirror of
https://github.com/matrix-construct/construct
synced 2024-12-11 08:02:59 +01:00
115 lines
3.2 KiB
C++
115 lines
3.2 KiB
C++
// Matrix Construct
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//
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// Copyright (C) Matrix Construct Developers, Authors & Contributors
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// Copyright (C) 2016-2018 Jason Volk <jason@zemos.net>
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//
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// Permission to use, copy, modify, and/or distribute this software for any
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// purpose with or without fee is hereby granted, provided that the above
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// copyright notice and this permission notice is present in all copies. The
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// full license for this software is available in the LICENSE file.
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#pragma once
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#define HAVE_IRCD_UTIL_CALLBACKS_H
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namespace ircd {
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inline namespace util
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{
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/// The purpose of callbacks is simply explained with an analogy out of
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/// browser-javascript land: it is window.onload.addEventListener() in lieu
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/// of assigning window.onload = function(). This is a list of multiple
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/// callbacks listening for invocation. The listener is responsible for
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/// both adding and removing itself using the std list interface (Note:
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/// convenience templates for this which elide as much boilerplate as
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/// possible have been provided below).
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///
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/// The template provides an option for whether exceptions should propagate
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/// to the caller. If they propagate, all listeners after the exception won't
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/// be invoked.
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///
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template<class prototype = void (void),
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bool exceptions = true>
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struct callbacks;
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template<class prototype>
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struct callbacks<prototype, true>;
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template<class prototype>
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struct callbacks<prototype, false>;
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}}
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template<class prototype>
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struct ircd::util::callbacks<prototype, true>
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:std::list<std::function<prototype>>
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{
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struct callback;
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using proto_type = prototype;
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using list_type = std::list<std::function<prototype>>;
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template<class... args>
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void operator()(args&&... a) const
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{
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for(const auto &func : *this)
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func(std::forward<args>(a)...);
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}
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callbacks() = default;
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callbacks(callbacks &&) = default;
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callbacks(const callbacks &) = delete;
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callbacks &operator=(callbacks &&) = default;
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callbacks &operator=(const callbacks &) = delete;
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};
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template<class prototype>
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struct ircd::util::callbacks<prototype, false>
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:std::list<std::function<prototype>>
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{
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struct callback;
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using proto_type = prototype;
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using list_type = std::list<std::function<prototype>>;
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template<class... args>
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void operator()(args&&... a) const
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{
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for(const auto &func : *this) try
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{
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func(std::forward<args>(a)...);
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}
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catch(const std::exception &e)
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{
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// Logging isn't available in ircd::util;
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// just silently drop and continue.
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}
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}
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callbacks() = default;
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callbacks(callbacks &&) = default;
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callbacks(const callbacks &) = delete;
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callbacks &operator=(callbacks &&) = default;
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callbacks &operator=(const callbacks &) = delete;
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};
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template<class prototype>
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struct ircd::util::callbacks<prototype, true>::callback
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:util::unique_iterator<list_type>
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{
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template<class function>
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callback(callbacks &c, function&& f)
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:util::unique_iterator<list_type>
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{
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c, c.emplace(end(c), std::forward<function>(f))
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}
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{}
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};
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template<class prototype>
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struct ircd::util::callbacks<prototype, false>::callback
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:util::unique_iterator<list_type>
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{
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template<class function>
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callback(callbacks &c, function&& f)
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:util::unique_iterator<list_type>
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{
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c, c.emplace(end(c), std::forward<function>(f))
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}
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{}
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};
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