SharedObjects.h

#pragma once
 
/* <editor-fold desc="MIT License">
 
Copyright(c) 2022 Robert Osfield
 
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
 
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
 
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
</editor-fold> */
 
#include <vsg/core/Inherit.h>
#include <vsg/core/compare.h>
#include <vsg/io/stream.h>
 
#include <map>
#include <mutex>
#include <ostream>
#include <set>
 
namespace vsg
{
 
    class VSG_DECLSPEC SharedObjects : public Inherit<Object, SharedObjects>
    {
    public:
        SharedObjects();
 
        template<class T>
        ref_ptr<T> shared_default()
        {
            std::scoped_lock<std::recursive_mutex> lock(_mutex);
 
            auto id = std::type_index(typeid(T));
            auto& def = _defaults[id];
            auto def_T = def.cast<T>(); // should be able to do a static cast
            if (!def_T)
            {
                def_T = T::create();
                auto& shared_objects = _sharedObjects[id];
                if (auto itr = shared_objects.find(def_T); itr != shared_objects.end())
                {
                    def_T = (static_cast<T*>(itr->get()));
                }
                else
                {
                    shared_objects.insert(def_T);
                }
 
                def = def_T;
            }
 
            return def_T;
        }
 
        template<class T>
        void share(ref_ptr<T>& object)
        {
            std::scoped_lock<std::recursive_mutex> lock(_mutex);
 
            auto id = std::type_index(typeid(T));
            auto& shared_objects = _sharedObjects[id];
            if (auto itr = shared_objects.find(object); itr != shared_objects.end())
            {
                object = ref_ptr<T>(static_cast<T*>(itr->get()));
                return;
            }
 
            shared_objects.insert(object);
        }
 
        template<class T, typename Func>
        void share(ref_ptr<T>& object, Func init)
        {
            std::scoped_lock<std::recursive_mutex> lock(_mutex);
 
            auto id = std::type_index(typeid(T));
            auto& shared_objects = _sharedObjects[id];
            if (auto itr = shared_objects.find(object); itr != shared_objects.end())
            {
                object = ref_ptr<T>(static_cast<T*>(itr->get()));
                return;
            }
 
            init(object);
 
            shared_objects.insert(object);
        }
 
        template<class C>
        void share(C& container)
        {
            for (auto& object : container)
            {
                share(object);
            }
        }
 
        std::set<Path> excludedExtensions;
 
        virtual bool suitable(const Path& filename) const;
 
        virtual bool contains(const Path& filename, ref_ptr<const Options> options = {}) const;
 
        virtual void add(ref_ptr<Object> object, const Path& filename, ref_ptr<const Options> options = {});
 
        virtual bool remove(const Path& filename, ref_ptr<const Options> options = {});
 
        void clear();
 
        // clear all the singly referenced objects
        void prune();
 
        void report(std::ostream& out);
 
    protected:
        virtual ~SharedObjects();
 
        mutable std::recursive_mutex _mutex;
        std::map<std::type_index, ref_ptr<Object>> _defaults;
        std::map<std::type_index, std::set<ref_ptr<Object>, DereferenceLess>> _sharedObjects;
    };
    VSG_type_name(vsg::SharedObjects);
 
    class LoadedObject : public Inherit<Object, LoadedObject>
    {
    public:
        Path filename;
        ref_ptr<const Options> options;
        ref_ptr<Object> object;
 
        LoadedObject(const Path& in_filename, ref_ptr<const Options> in_options, ref_ptr<Object> in_object = {}) :
            filename(in_filename),
            options(in_options),
            object(in_object) {}
 
        int compare(const Object& rhs_object) const override
        {
            int result = Object::compare(rhs_object);
            if (result != 0) return result;
 
            auto& rhs = static_cast<decltype(*this)>(rhs_object);
 
            if ((result = filename.compare(rhs.filename))) return result;
            return compare_pointer(options, rhs.options);
        }
    };
    VSG_type_name(vsg::LoadedObject);
 
} // namespace vsg