IfcOpenShell/src/ifcparse/express.h

/********************************************************************************
 *                                                                              *
 * This file is part of IfcOpenShell.                                           *
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 * IfcOpenShell is free software: you can redistribute it and/or modify         *
 * it under the terms of the Lesser GNU General Public License as published by  *
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 * (at your option) any later version.                                          *
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of               *
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the                 *
 * Lesser GNU General Public License for more details.                          *
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 * You should have received a copy of the Lesser GNU General Public License     *
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 ********************************************************************************/

#ifndef IFCBASECLASS_H
#define IFCBASECLASS_H

#include "Argument.h"
#include "ifc_parse_api.h"
#include "IfcSchema.h"
#include "utils.h"

#include <atomic>
#include <boost/shared_ptr.hpp>

class aggregate_of_instance;

namespace IfcParse {
class IfcFile;
namespace impl {
struct in_memory_file_storage;
}
} // namespace IfcParse

class InstanceData;
class AttributeValue;

namespace express {

class Base;
class Select;
class Entity;
class DeclaredType;

class IFC_PARSE_API Base {
  protected:
    std::weak_ptr<InstanceData> data_;
  public:
    operator bool() const {
        return !data_.expired();
    }

    bool operator<(const Base& other) const {
        return data() < other.data();
    }

    bool operator==(const Base& other) const {
        return data() == other.data();
    }

    bool operator!=(const Base& other) const {
        return !(*this == other);
    }

    Base() {};
    Base(const std::weak_ptr<InstanceData>& data) : data_(data) {}

    const InstanceData* data() const;
      InstanceData* data();
    const std::weak_ptr<InstanceData>& data_weak() const { return data_; }

    const IfcParse::declaration& declaration() const;

    template <typename T>
    typename std::enable_if<
        (!std::is_base_of_v<express::Base, T> || std::is_same_v<express::Base, T>),
        void>::type
    set_attribute_value(size_t i, const T& t);

    template <typename T>
    typename std::enable_if<
        (!std::is_base_of_v<express::Base, T> || std::is_same_v<express::Base, T>),
        void>::type
    set_attribute_value(const std::string& name, const T& t);

    void set_attribute_value(size_t i, const express::Base& p);
    void set_attribute_value(const std::string& name, const express::Base& p);
    
    void unset_attribute_value(size_t i);

    AttributeValue get_attribute_value(size_t index) const;

    uint32_t identity() const;

    uint32_t id() const;

    void toString(std::ostream&, bool upper = false) const;

    template <class T>
    T as() const {
        if constexpr (std::is_same_v<Entity, T>) {
            if (declaration().as_entity() != nullptr) {
                return T(data_weak());
            } else {
                return T{};
            }
        } else if constexpr (std::is_same_v<DeclaredType, T>) {
            if (declaration().as_entity() == nullptr) {
                return T(data_weak());
            } else {
                return T{};
            }
        } else if constexpr (std::is_same_v<Select, T>) {
            static_assert(std::is_same_v<Select, T>, "Select is abstract");
        } else {
            if (declaration().is(T::Class())) {
                return T(data_weak());
            } else {
                return T{};
            }
        }     
    }
};

class IFC_PARSE_API Entity : public Base {
  public:
    Entity() {}
    Entity(const std::weak_ptr<InstanceData>& data) : Base(data) {}

    AttributeValue get(const std::string& name) const;

    template <typename T>
    T get_value(const std::string& name) const;

    template <typename T>
    T get_value(const std::string& name, const T& default_value) const;

    std::vector<express::Entity> get_inverse(const std::string& name) const;

    // unsigned set_id(const std::optional<unsigned>& i);

    void populate_derived();
};

class IFC_PARSE_API Select : public Base {
  public:
    Select() {}
    // Select are constructed from Base as cast functions, not from data directly
    Select(const Base& base) : Base(base.data_weak()) {}

    Base concrete() const {
        return Base(data_weak());
    }
};

// @todo Investigate whether these should be template classes instead
// @todo currently this class doesn't do much, decide whether to keep
//       it or move certain functionality from Base downwards to
//       Entity and DeclaredType
class IFC_PARSE_API DeclaredType : public Base {
  public:
    DeclaredType() {}
    DeclaredType(const std::weak_ptr<InstanceData>& data) : Base(data) {}
};

} // namespace express

namespace std {

template <>
struct hash<express::Base> {
    std::size_t operator()(const express::Base& c) const noexcept {
        return std::hash<void*>{}((void*) c.data());
    }
};

template <>
struct hash<express::Entity> {
    std::size_t operator()(const express::Entity& c) const noexcept {
        return std::hash<void*>{}((void*)c.data());
    }
};

} // namespace std

template <typename T, typename U>
std::vector<T> cast_vector(const std::vector<U>& vs) {
    std::vector<T> result;
    for (const auto& v : vs) {
        if constexpr (std::is_base_of_v<T, U>) {
            // For a base or identity transform we can just rely on static cast
            result.push_back(v);
        } else if constexpr (std::is_base_of_v<express::Select, U> && std::is_same_v<T, express::Base>) {
            // From a select to concrete we simply call the appropriate method
            result.push_back(v.concrete());
        } else {
            if (auto u = v.template as<T>()) {
                result.push_back(u);
            }
        }
    }
    return result;
}

template <typename T, typename U>
std::vector<std::vector<T>> cast_vector_vector(const std::vector<std::vector<U>>& vs) {
    std::vector<std::vector<T>> result;
    for (const auto& v : vs) {
        result.push_back(cast_vector<T>(v));
    }
    return result;
}

#endif