78 lines
2.2 KiB
C++
78 lines
2.2 KiB
C++
// Copyright 2014 Renato Tegon Forti, Antony Polukhin.
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// Copyright 2015-2019 Antony Polukhin.
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//
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// Distributed under the Boost Software License, Version 1.0.
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// (See accompanying file LICENSE_1_0.txt
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// or copy at http://www.boost.org/LICENSE_1_0.txt)
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//[plugcpp_my_plugin_refcounting_api
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#include "../tutorial_common/my_plugin_api.hpp"
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#include <boost/dll/config.hpp>
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class my_refcounting_api: public my_plugin_api {
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public:
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// Returns path to shared object that holds a plugin.
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// Must be instantiated in plugin.
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virtual boost::dll::fs::path location() const = 0;
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};
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//]
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//[plugcpp_library_holding_deleter_api_bind
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#include <boost/shared_ptr.hpp>
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#include <boost/make_shared.hpp>
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#include <boost/dll/shared_library.hpp>
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struct library_holding_deleter {
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boost::shared_ptr<boost::dll::shared_library> lib_;
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void operator()(my_refcounting_api* p) const {
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delete p;
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}
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};
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inline boost::shared_ptr<my_refcounting_api> bind(my_refcounting_api* plugin) {
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// getting location of the shared library that holds the plugin
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boost::dll::fs::path location = plugin->location();
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// `make_shared` is an efficient way to create a shared pointer
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boost::shared_ptr<boost::dll::shared_library> lib
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= boost::make_shared<boost::dll::shared_library>(location);
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library_holding_deleter deleter;
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deleter.lib_ = lib;
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return boost::shared_ptr<my_refcounting_api>(
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plugin, deleter
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);
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}
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//]
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//[plugcpp_get_plugin_refcounting
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#include <boost/dll/import.hpp>
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#include <boost/function.hpp>
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inline boost::shared_ptr<my_refcounting_api> get_plugin(
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boost::dll::fs::path path, const char* func_name)
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{
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typedef my_refcounting_api*(func_t)();
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boost::function<func_t> creator = boost::dll::import_alias<func_t>(
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path,
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func_name,
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boost::dll::load_mode::append_decorations // will be ignored for executable
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);
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// `plugin` does not hold a reference to shared library. If `creator` will go out of scope,
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// then `plugin` can not be used.
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my_refcounting_api* plugin = creator();
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// Returned variable holds a reference to
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// shared_library and it is safe to use it.
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return bind( plugin );
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// `creator` goes out of scope here and will be destroyed.
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}
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//]
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