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| -rw-r--r-- | src/base/injector.hh | 230 |
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diff --git a/src/base/injector.hh b/src/base/injector.hh new file mode 100644 index 0000000..c6848a6 --- /dev/null +++ b/src/base/injector.hh @@ -0,0 +1,230 @@ +/** + * Copyright (c) 2021, Timothy Stack + * + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * * Redistributions of source code must retain the above copyright notice, this + * list of conditions and the following disclaimer. + * * Redistributions in binary form must reproduce the above copyright notice, + * this list of conditions and the following disclaimer in the documentation + * and/or other materials provided with the distribution. + * * Neither the name of Timothy Stack nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ''AS IS'' AND ANY + * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED + * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE + * DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY + * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES + * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; + * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND + * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS + * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + * @file injector.hh + */ + +#ifndef lnav_injector_hh +#define lnav_injector_hh + +#include <map> +#include <memory> +#include <type_traits> +#include <vector> + +#include <assert.h> + +#include "base/lnav_log.hh" + +namespace injector { + +enum class scope { + undefined, + none, + singleton, +}; + +template<typename Annotation> +void force_linking(Annotation anno); + +template<class...> +using void_t = void; + +template<typename T, typename... Annotations> +struct with_annotations { + T value; +}; + +template<class, class = void> +struct has_injectable : std::false_type {}; + +template<class T> +struct has_injectable<T, void_t<typename T::injectable>> : std::true_type {}; + +template<typename T, typename... Annotations> +struct singleton_storage { + static scope get_scope() { return ss_scope; } + + static T* get() + { + static int _[] = {0, (force_linking(Annotations{}), 0)...}; + (void) _; + return ss_data; + } + + static std::shared_ptr<T> get_owner() + { + static int _[] = {0, (force_linking(Annotations{}), 0)...}; + (void) _; + return ss_owner; + } + + static std::shared_ptr<T> create() + { + static int _[] = {0, (force_linking(Annotations{}), 0)...}; + (void) _; + return ss_factory(); + } + +protected: + static scope ss_scope; + static T* ss_data; + static std::shared_ptr<T> ss_owner; + static std::function<std::shared_ptr<T>()> ss_factory; +}; + +template<typename T, typename... Annotations> +T* singleton_storage<T, Annotations...>::ss_data = nullptr; + +template<typename T, typename... Annotations> +scope singleton_storage<T, Annotations...>::ss_scope = scope::undefined; + +template<typename T, typename... Annotations> +std::shared_ptr<T> singleton_storage<T, Annotations...>::ss_owner; + +template<typename T, typename... Annotations> +std::function<std::shared_ptr<T>()> + singleton_storage<T, Annotations...>::ss_factory; + +template<typename T> +struct Impl { + using type = T; +}; + +template<typename T> +struct multiple_storage { + static std::vector<std::shared_ptr<T>> create() + { + std::vector<std::shared_ptr<T>> retval; + + for (const auto& pair : get_factories()) { + retval.template emplace_back(pair.second()); + } + return retval; + } + +protected: + using factory_map_t + = std::map<std::string, std::function<std::shared_ptr<T>()>>; + + static factory_map_t& get_factories() + { + static factory_map_t retval; + + return retval; + } +}; + +template<typename T, + typename... Annotations, + std::enable_if_t<std::is_reference<T>::value, bool> = true> +T +get() +{ + using plain_t = std::remove_const_t<std::remove_reference_t<T>>; + + return *singleton_storage<plain_t, Annotations...>::get(); +} + +template<typename T, + typename... Annotations, + std::enable_if_t<std::is_pointer<T>::value, bool> = true> +T +get() +{ + using plain_t = std::remove_const_t<std::remove_pointer_t<T>>; + + return singleton_storage<plain_t, Annotations...>::get(); +} + +template<class T> +struct is_shared_ptr : std::false_type {}; + +template<class T> +struct is_shared_ptr<std::shared_ptr<T>> : std::true_type {}; + +template<class T> +struct is_vector : std::false_type {}; + +template<class T> +struct is_vector<std::vector<T>> : std::true_type {}; + +template<typename I, typename R, typename... IArgs, typename... Args> +std::function<std::shared_ptr<I>()> create_from_injectable(R (*)(IArgs...), + Args&... args); + +template<typename T, + typename... Args, + std::enable_if_t<has_injectable<typename T::element_type>::value, bool> + = true, + std::enable_if_t<is_shared_ptr<T>::value, bool> = true> +T +get(Args&... args) +{ + typename T::element_type::injectable* i = nullptr; + + if (singleton_storage<typename T::element_type>::get_scope() + == scope::singleton) + { + return singleton_storage<typename T::element_type>::get_owner(); + } + return create_from_injectable<typename T::element_type>(i, args...)(); +} + +template< + typename T, + typename... Annotations, + std::enable_if_t<!has_injectable<typename T::element_type>::value, bool> + = true, + std::enable_if_t<is_shared_ptr<T>::value, bool> = true> +T +get() +{ + return singleton_storage<typename T::element_type, + Annotations...>::get_owner(); +} + +template<typename T, std::enable_if_t<is_vector<T>::value, bool> = true> +T +get() +{ + return multiple_storage<typename T::value_type::element_type>::create(); +} + +template<typename I, typename R, typename... IArgs, typename... Args> +std::function<std::shared_ptr<I>()> +create_from_injectable(R (*)(IArgs...), Args&... args) +{ + return [&]() { + return std::make_shared<I>(args..., ::injector::get<IArgs>()...); + }; +} + +} // namespace injector + +#endif |