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 //  Copyright 2016 Klemens Morgenstern
 //  Copyright Antony Polukhin, 2019-2023
 //
 // Distributed under the Boost Software License, Version 1.0.
 // (See accompanying file LICENSE_1_0.txt
 // or copy at http://www.boost.org/LICENSE_1_0.txt)
 
 #ifndef BOOST_DLL_SMART_LIBRARY_HPP_
 #define BOOST_DLL_SMART_LIBRARY_HPP_
 
 /// \file boost/dll/smart_library.hpp
 /// \warning Extremely experimental! Requires C++11! Will change in next version of Boost! boost/dll/smart_library.hpp is not included in boost/dll.hpp
 /// \brief Contains the boost::dll::experimental::smart_library class for loading mangled symbols.
 
 #include <boost/dll/config.hpp>
 #if defined(_MSC_VER) // MSVC, Clang-cl, and ICC on Windows
 #   include <boost/dll/detail/demangling/msvc.hpp>
 #else
 #   include <boost/dll/detail/demangling/itanium.hpp>
 #endif
 
 #if (__cplusplus < 201103L) && (!defined(_MSVC_LANG) || _MSVC_LANG < 201103L)
 #  error This file requires C++11 at least!
 #endif
 
 #include <boost/dll/shared_library.hpp>
 #include <boost/dll/detail/get_mem_fn_type.hpp>
 #include <boost/dll/detail/ctor_dtor.hpp>
 #include <boost/dll/detail/type_info.hpp>
 #include <boost/type_traits/is_object.hpp>
 #include <boost/type_traits/is_void.hpp>
 #include <boost/type_traits/is_function.hpp>
 
 
 
 namespace boost {
 namespace dll {
 namespace experimental {
 
 using boost::dll::detail::constructor;
 using boost::dll::detail::destructor;
 
 /*!
 * \brief This class is an extension of \ref shared_library, which allows to load C++ symbols.
 *
 * This class allows type safe loading of overloaded functions, member-functions, constructors and variables.
 * It also allows to overwrite classes so they can be loaded, while being declared with different names.
 *
 * \warning Is still very experimental.
 *
 * Currently known limitations:
 *
 * Member functions must be defined outside of the class to be exported. That is:
 * \code
 * //not exported:
 * struct BOOST_SYMBOL_EXPORT my_class { void func() {}};
 * //exported
 * struct BOOST_SYMBOL_EXPORT my_class { void func();};
 * void my_class::func() {};
 * \endcode
 *
 * With the current analysis, the first version does get exported in MSVC.
 * MinGW also does export it, BOOST_SYMBOL_EXPORT is written before it. To allow this on windows one can use
 * BOOST_DLL_MEMBER_EXPORT for this, so that MinGW and MSVC can provide those functions. This does however not work with gcc on linux.
 *
 * Direct initialization of members.
 * On linux the following member variable i will not be initialized when using the allocating constructor:
 * \code
 * struct BOOST_SYMBOL_EXPORT my_class { int i; my_class() : i(42) {} };
 * \endcode
 *
 * This does however not happen when the value is set inside the constructor function.
 */
 class smart_library {
     shared_library _lib;
     detail::mangled_storage_impl _storage;
 
 public:
     /*!
      * Get the underlying shared_library
      */
     const shared_library &shared_lib() const {return _lib;}
 
     using mangled_storage = detail::mangled_storage_impl;
     /*!
     * Access to the mangled storage, which is created on construction.
     *
     * \throw Nothing.
     */
     const mangled_storage &symbol_storage() const {return _storage;}
 
     ///Overload, for current development.
     mangled_storage &symbol_storage() {return _storage;}
 
     //! \copydoc shared_library::shared_library()
     smart_library() BOOST_NOEXCEPT {};
 
     //! \copydoc shared_library::shared_library(const boost::dll::fs::path& lib_path, load_mode::type mode = load_mode::default_mode)
     smart_library(const boost::dll::fs::path& lib_path, load_mode::type mode = load_mode::default_mode) {
         _lib.load(lib_path, mode);
         _storage.load(lib_path);
     }
 
     //! \copydoc shared_library::shared_library(const boost::dll::fs::path& lib_path, boost::dll::fs::error_code& ec, load_mode::type mode = load_mode::default_mode)
     smart_library(const boost::dll::fs::path& lib_path, boost::dll::fs::error_code& ec, load_mode::type mode = load_mode::default_mode) {
         load(lib_path, mode, ec);
     }
 
     //! \copydoc shared_library::shared_library(const boost::dll::fs::path& lib_path, load_mode::type mode, boost::dll::fs::error_code& ec)
     smart_library(const boost::dll::fs::path& lib_path, load_mode::type mode, boost::dll::fs::error_code& ec) {
         load(lib_path, mode, ec);
     }
     /*!
      * copy a smart_library object.
      *
      * \param lib A smart_library to move from.
      *
      * \throw Nothing.
      */
      smart_library(const smart_library & lib) BOOST_NOEXCEPT
          : _lib(lib._lib), _storage(lib._storage)
      {}
    /*!
     * Move a smart_library object.
     *
     * \param lib A smart_library to move from.
     *
     * \throw Nothing.
     */
     smart_library(BOOST_RV_REF(smart_library) lib) BOOST_NOEXCEPT
         : _lib(boost::move(lib._lib)), _storage(boost::move(lib._storage))
     {}
 
     /*!
       * Construct from a shared_library object.
       *
       * \param lib A shared_library to move from.
       *
       * \throw Nothing.
       */
       explicit smart_library(const shared_library & lib) BOOST_NOEXCEPT
           : _lib(lib)
       {
           _storage.load(lib.location());
       }
      /*!
      * Construct from a shared_library object.
      *
      * \param lib A shared_library to move from.
      *
      * \throw Nothing.
      */
      explicit smart_library(BOOST_RV_REF(shared_library) lib) BOOST_NOEXCEPT
          : _lib(boost::move(static_cast<shared_library&>(lib)))
      {
          _storage.load(lib.location());
      }
 
     /*!
     * Destroys the smart_library.
     * `unload()` is called if the DLL/DSO was loaded. If library was loaded multiple times
     * by different instances of shared_library, the actual DLL/DSO won't be unloaded until
     * there is at least one instance of shared_library.
     *
     * \throw Nothing.
     */
     ~smart_library() BOOST_NOEXCEPT {};
 
     //! \copydoc shared_library::load(const boost::dll::fs::path& lib_path, load_mode::type mode = load_mode::default_mode)
     void load(const boost::dll::fs::path& lib_path, load_mode::type mode = load_mode::default_mode) {
         boost::dll::fs::error_code ec;
         _storage.load(lib_path);
         _lib.load(lib_path, mode, ec);
 
         if (ec) {
             boost::dll::detail::report_error(ec, "load() failed");
         }
     }
 
     //! \copydoc shared_library::load(const boost::dll::fs::path& lib_path, boost::dll::fs::error_code& ec, load_mode::type mode = load_mode::default_mode)
     void load(const boost::dll::fs::path& lib_path, boost::dll::fs::error_code& ec, load_mode::type mode = load_mode::default_mode) {
         ec.clear();
         _storage.load(lib_path);
         _lib.load(lib_path, mode, ec);
     }
 
     //! \copydoc shared_library::load(const boost::dll::fs::path& lib_path, load_mode::type mode, boost::dll::fs::error_code& ec)
     void load(const boost::dll::fs::path& lib_path, load_mode::type mode, boost::dll::fs::error_code& ec) {
         ec.clear();
         _storage.load(lib_path);
         _lib.load(lib_path, mode, ec);
     }
 
     /*!
      * Load a variable from the referenced library.
      *
      * Unlinke shared_library::get this function will also load scoped variables, which also includes static class members.
      *
      * \note When mangled, MSVC will also check the type.
      *
      * \param name Name of the variable
      * \tparam T Type of the variable
      * \return A reference to the variable of type T.
      *
      * \throw \forcedlinkfs{system_error} if symbol does not exist or if the DLL/DSO was not loaded.
      */
     template<typename T>
     T& get_variable(const std::string &name) const {
         return _lib.get<T>(_storage.get_variable<T>(name));
     }
 
     /*!
      * Load a function from the referenced library.
      *
      * \b Example:
      *
      * \code
      * smart_library lib("test_lib.so");
      * typedef int      (&add_ints)(int, int);
      * typedef double (&add_doubles)(double, double);
      * add_ints     f1 = lib.get_function<int(int, int)>         ("func_name");
      * add_doubles  f2 = lib.get_function<double(double, double)>("func_name");
      * \endcode
      *
      * \note When mangled, MSVC will also check the return type.
      *
      * \param name Name of the function.
      * \tparam Func Type of the function, required for determining the overload
      * \return A reference to the function of type F.
      *
      * \throw \forcedlinkfs{system_error} if symbol does not exist or if the DLL/DSO was not loaded.
      */
     template<typename Func>
     Func& get_function(const std::string &name) const {
         return _lib.get<Func>(_storage.get_function<Func>(name));
     }
 
     /*!
      * Load a member-function from the referenced library.
      *
      * \b Example (import class is MyClass, which is available inside the library and the host):
      *
      * \code
      * smart_library lib("test_lib.so");
      *
      * typedef int      MyClass(*func)(int);
      * typedef int   MyClass(*func_const)(int) const;
      *
      * add_ints     f1 = lib.get_mem_fn<MyClass, int(int)>              ("MyClass::function");
      * add_doubles  f2 = lib.get_mem_fn<const MyClass, double(double)>("MyClass::function");
      * \endcode
      *
      * \note When mangled, MSVC will also check the return type.
      *
      * \param name Name of the function.
      * \tparam Class The class the function is a member of. If Class is const, the function will be assumed as taking a const this-pointer. The same applies for volatile.
      * \tparam Func Signature of the function, required for determining the overload
      * \return A pointer to the member-function with the signature provided
      *
      * \throw \forcedlinkfs{system_error} if symbol does not exist or if the DLL/DSO was not loaded.
      */
     template<typename Class, typename Func>
     typename boost::dll::detail::get_mem_fn_type<Class, Func>::mem_fn get_mem_fn(const std::string& name) const {
         return _lib.get<typename boost::dll::detail::get_mem_fn_type<Class, Func>::mem_fn>(
                 _storage.get_mem_fn<Class, Func>(name)
         );
     }
 
     /*!
      * Load a constructor from the referenced library.
      *
      * \b Example (import class is MyClass, which is available inside the library and the host):
      *
      * \code
      * smart_library lib("test_lib.so");
      *
      * constructor<MyClass(int)    f1 = lib.get_mem_fn<MyClass(int)>();
      * \endcode
      *
      * \tparam Signature Signature of the function, required for determining the overload. The return type is the class which this is the constructor of.
      * \return A constructor object.
      *
      * \throw \forcedlinkfs{system_error} if symbol does not exist or if the DLL/DSO was not loaded.
      */
     template<typename Signature>
     constructor<Signature> get_constructor() const {
         return boost::dll::detail::load_ctor<Signature>(_lib, _storage.get_constructor<Signature>());
     }
 
     /*!
      * Load a destructor from the referenced library.
      *
      * \b Example (import class is MyClass, which is available inside the library and the host):
      *
      * \code
      * smart_library lib("test_lib.so");
      *
      * destructor<MyClass>     f1 = lib.get_mem_fn<MyClass>();
      * \endcode
      *
      * \tparam Class The class whose destructor shall be loaded
      * \return A destructor object.
      *
      * \throw \forcedlinkfs{system_error} if symbol does not exist or if the DLL/DSO was not loaded.
      *
      */
     template<typename Class>
     destructor<Class> get_destructor() const {
         return boost::dll::detail::load_dtor<Class>(_lib, _storage.get_destructor<Class>());
     }
     /*!
      * Load the typeinfo of the given type.
      *
      * \b Example (import class is MyClass, which is available inside the library and the host):
      *
      * \code
      * smart_library lib("test_lib.so");
      *
      * std::type_info &ti = lib.get_Type_info<MyClass>();
      * \endcode
      *
      * \tparam Class The class whose typeinfo shall be loaded
      * \return A reference to a type_info object.
      *
      * \throw \forcedlinkfs{system_error} if symbol does not exist or if the DLL/DSO was not loaded.
      *
      */
     template<typename Class>
     const std::type_info& get_type_info() const
     {
         return boost::dll::detail::load_type_info<Class>(_lib, _storage);
     }
     /**
      * This function can be used to add a type alias.
      *
      * This is to be used, when a class shall be imported, which is not declared on the host side.
      *
      * Example:
      * \code
      * smart_library lib("test_lib.so");
      *
      * lib.add_type_alias<MyAlias>("MyClass"); //when using MyAlias, the library will look for MyClass
      *
      * //get the destructor of MyClass
      * destructor<MyAlias> dtor = lib.get_destructor<MyAlias>();
      * \endcode
      *
      *
      * \param name Name of the class the alias is for.
      *
      * \attention If the alias-type is not large enough for the imported class, it will result in undefined behaviour.
      * \warning The alias will only be applied for the type signature, it will not replace the token in the scoped name.
      */
     template<typename Alias> void add_type_alias(const std::string& name) {
         this->_storage.add_alias<Alias>(name);
     }
 
     //! \copydoc shared_library::unload()
     void unload() BOOST_NOEXCEPT {
         _storage.clear();
         _lib.unload();
     }
 
     //! \copydoc shared_library::is_loaded() const
     bool is_loaded() const BOOST_NOEXCEPT {
         return _lib.is_loaded();
     }
 
     //! \copydoc shared_library::operator!() const
     bool operator!() const BOOST_NOEXCEPT {
         return !is_loaded();
     }
 
     //! \copydoc shared_library::operator bool() const
     BOOST_EXPLICIT_OPERATOR_BOOL()
 
     //! \copydoc shared_library::has(const char* symbol_name) const
     bool has(const char* symbol_name) const BOOST_NOEXCEPT {
         return _lib.has(symbol_name);
     }
 
     //! \copydoc shared_library::has(const std::string& symbol_name) const
     bool has(const std::string& symbol_name) const BOOST_NOEXCEPT {
         return _lib.has(symbol_name);
     }
 
     //! \copydoc shared_library::assign(const shared_library& lib)
     smart_library& assign(const smart_library& lib) {
        _lib.assign(lib._lib);
        _storage.assign(lib._storage);
        return *this;
     }
 
     //! \copydoc shared_library::swap(shared_library& rhs)
     void swap(smart_library& rhs) BOOST_NOEXCEPT {
         _lib.swap(rhs._lib);
         _storage.swap(rhs._storage);
     }
 };
 
 /// Very fast equality check that compares the actual DLL/DSO objects. Throws nothing.
 inline bool operator==(const smart_library& lhs, const smart_library& rhs) BOOST_NOEXCEPT {
     return lhs.shared_lib().native() == rhs.shared_lib().native();
 }
 
 /// Very fast inequality check that compares the actual DLL/DSO objects. Throws nothing.
 inline bool operator!=(const smart_library& lhs, const smart_library& rhs) BOOST_NOEXCEPT {
     return lhs.shared_lib().native() != rhs.shared_lib().native();
 }
 
 /// Compare the actual DLL/DSO objects without any guarantee to be stable between runs. Throws nothing.
 inline bool operator<(const smart_library& lhs, const smart_library& rhs) BOOST_NOEXCEPT {
     return lhs.shared_lib().native() < rhs.shared_lib().native();
 }
 
 /// Swaps two shared libraries. Does not invalidate symbols and functions loaded from libraries. Throws nothing.
 inline void swap(smart_library& lhs, smart_library& rhs) BOOST_NOEXCEPT {
     lhs.swap(rhs);
 }
 
 
 #ifdef BOOST_DLL_DOXYGEN
 /** Helper functions for overloads.
  *
  * Gets either a variable, function or member-function, depending on the signature.
  *
  * @code
  * smart_library sm("lib.so");
  * get<int>(sm, "space::value"); //import a variable
  * get<void(int)>(sm, "space::func"); //import a function
  * get<some_class, void(int)>(sm, "space::class_::mem_fn"); //import a member function
  * @endcode
  *
  * @param sm A reference to the @ref smart_library
  * @param name The name of the entity to import
  */
 template<class T, class T2>
 void get(const smart_library& sm, const std::string &name);
 #endif
 
 template<class T>
 typename boost::enable_if<boost::is_object<T>, T&>::type get(const smart_library& sm, const std::string &name)
 
 {
     return sm.get_variable<T>(name);
 }
 
 template<class T>
 typename boost::enable_if<boost::is_function<T>, T&>::type get(const smart_library& sm, const std::string &name)
 {
     return sm.get_function<T>(name);
 }
 
 template<class Class, class Signature>
 auto get(const smart_library& sm, const std::string &name) -> typename detail::get_mem_fn_type<Class, Signature>::mem_fn
 {
     return sm.get_mem_fn<Class, Signature>(name);
 }
 
 
 } /* namespace experimental */
 } /* namespace dll */
 } /* namespace boost */
 
 #endif /* BOOST_DLL_SMART_LIBRARY_HPP_ */

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