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
{
 
    // forward declare
    class SuitableForSharing;
 
    class VSG_DECLSPEC SharedObjects : public Inherit<Object, SharedObjects>
    {
    public:
        SharedObjects();
 
        template<class T>
        ref_ptr<T> shared_default();
 
        template<class T>
        void share(ref_ptr<T>& object);
 
        template<class T, typename Func>
        void share(ref_ptr<T>& object, Func init);
 
        template<class C>
        void share(C& container);
 
        ref_ptr<SuitableForSharing> suitableForSharing;
 
        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 singularly 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 VSG_DECLSPEC LoadedObject : public Inherit<Object, LoadedObject>
    {
    public:
        Path filename;
        ref_ptr<Options> options;
        ref_ptr<Object> object;
 
        LoadedObject(const Path& in_filename, ref_ptr<const Options> in_options, ref_ptr<Object> in_object = {});
 
        void traverse(Visitor& visitor) override;
        void traverse(ConstVisitor& visitor) const override;
 
        int compare(const Object& rhs_object) const override;
    };
    VSG_type_name(vsg::LoadedObject);
 
    class VSG_DECLSPEC SuitableForSharing : public Inherit<ConstVisitor, SuitableForSharing>
    {
    public:
        bool suitableForSharing = true;
 
        void apply(const Object& object) override;
        void apply(const PagedLOD& plod) override;
 
        bool suitable(const Object* object)
        {
            suitableForSharing = true;
            if (object) object->accept(*this);
            return suitableForSharing;
        }
    };
    VSG_type_name(vsg::SuitableForSharing);
 
    // implementation of template method
    template<class T>
    ref_ptr<T> SharedObjects::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;
    }
 
    // implementation of template method
    template<class T>
    void SharedObjects::share(ref_ptr<T>& object)
    {
        std::scoped_lock<std::recursive_mutex> lock(_mutex);
 
        if (suitableForSharing && !suitableForSharing->suitable(object.get())) return;
 
        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);
    }
 
    // implementation of template method
    template<class T, typename Func>
    void SharedObjects::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);
 
        {
            std::scoped_lock<std::recursive_mutex> lock(_mutex);
            auto id = std::type_index(typeid(T));
            auto& shared_objects = _sharedObjects[id];
            if (suitableForSharing && suitableForSharing->suitable(object.get()))
            {
                shared_objects.insert(object);
            }
        }
    }
 
    // implementation of template method
    template<class C>
    void SharedObjects::share(C& container)
    {
        for (auto& object : container)
        {
            share(object);
        }
    }
 
} // namespace vsg