surfaceFactoryCache.h

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//
//   Copyright 2021 Pixar
//
//   Licensed under the terms set forth in the LICENSE.txt file available at
//   https://opensubdiv.org/license.
//
 
#ifndef OPENSUBDIV3_BFR_SURFACE_FACTORY_CACHE_H
#define OPENSUBDIV3_BFR_SURFACE_FACTORY_CACHE_H
 
#include "../version.h"
 
#include "../bfr/irregularPatchType.h"
 
#include <map>
#include <cstdint>
 
namespace OpenSubdiv {
namespace OPENSUBDIV_VERSION {
 
namespace Bfr {

//
//  Initial/expected use requires simple searches of and additions to the
//  cache by the SurfaceFactory or its Builders.  Longer term, with the
//  possibility of instances of caches being shared between meshes and
//  factories, additional options and/or public methods may be warranted
//  to limit what is cached or to prune the cache if it gets too large.
//
class SurfaceFactoryCache {
public:
    SurfaceFactoryCache();
    virtual ~SurfaceFactoryCache();
 
    SurfaceFactoryCache(SurfaceFactoryCache const &) = delete;
    SurfaceFactoryCache & operator=(SurfaceFactoryCache const &) = delete;
 
protected:
    //  Access restricted to the Factory, its Builders, etc.
    friend class SurfaceFactory;
 
    typedef std::uint64_t                     KeyType;
    typedef internal::IrregularPatchSharedPtr DataType;
 
protected:
    size_t Size() const { return _map.size(); }
 
    //
    //  Potential overrides by subclasses for thread-safety:
    //
    virtual DataType Find(KeyType const & key) const;
    virtual DataType Add(KeyType const & key, DataType const & data);
 
    //
    //  Common implementation used by all subclasses:
    //
    DataType find(KeyType const & key) const;
    DataType add(KeyType const & key, DataType const & data);
 
private:
    typedef std::map<KeyType, DataType> MapType;
 
    MapType _map;
};

//  Separate read and write locks are provided to support mutex types
//  allowing shared (read) or exclusive (write) access.
// 
template <class MUTEX_TYPE, class READ_LOCK_GUARD_TYPE,
                            class WRITE_LOCK_GUARD_TYPE>
class SurfaceFactoryCacheThreaded : public SurfaceFactoryCache {
public:
    SurfaceFactoryCacheThreaded() : SurfaceFactoryCache() { }
    ~SurfaceFactoryCacheThreaded() override = default;
 
protected:
    //
    //  Virtual overrides from base:
    //
    DataType Find(KeyType const & key) const override {
        READ_LOCK_GUARD_TYPE lockGuard(_mutex);
        return find(key);
    }
 
    DataType Add(KeyType const & key, DataType const & data) override {
        WRITE_LOCK_GUARD_TYPE lockGuard(_mutex);
        return add(key, data);
    }
 
private:
    MUTEX_TYPE mutable _mutex;
};
 
} // end namespace Bfr
 
} // end namespace OPENSUBDIV_VERSION
using namespace OPENSUBDIV_VERSION;
 
} // end namespace OpenSubdiv
 
#endif /* OPENSUBDIV3_BFR_SURFACE_FACTORY_CACHE_H */