BLI_generic_pointer.hh

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/* SPDX-FileCopyrightText: 2023 Blender Authors
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */
 
#pragma once
 
#include "BLI_cpp_type.hh"
 
namespace blender {

class GMutablePointer {
 private:
  const CPPType *type_ = nullptr;
  void *data_ = nullptr;
 
 public:
  GMutablePointer() = default;
 
  GMutablePointer(const CPPType *type, void *data = nullptr) : type_(type), data_(data)
  {
    /* If there is data, there has to be a type. */
    BLI_assert(data_ == nullptr || type_ != nullptr);
  }
 
  GMutablePointer(const CPPType &type, void *data = nullptr) : GMutablePointer(&type, data) {}
 
  template<typename T, BLI_ENABLE_IF(!std::is_void_v<T>)>
  GMutablePointer(T *data) : GMutablePointer(&CPPType::get<T>(), data)
  {
  }
 
  void *get() const
  {
    return data_;
  }
 
  const CPPType *type() const
  {
    return type_;
  }
 
  template<typename T> T *get() const
  {
    BLI_assert(this->is_type<T>());
    return static_cast<T *>(data_);
  }
 
  template<typename T> bool is_type() const
  {
    return type_ != nullptr && type_->is<T>();
  }
 
  template<typename T> T relocate_out()
  {
    BLI_assert(this->is_type<T>());
    T value;
    type_->relocate_assign(data_, &value);
    data_ = nullptr;
    type_ = nullptr;
    return value;
  }
 
  void destruct()
  {
    BLI_assert(data_ != nullptr);
    type_->destruct(data_);
  }
};

class GPointer {
 private:
  const CPPType *type_ = nullptr;
  const void *data_ = nullptr;
 
 public:
  GPointer() = default;
 
  GPointer(GMutablePointer ptr) : type_(ptr.type()), data_(ptr.get()) {}
 
  GPointer(const CPPType *type, const void *data = nullptr) : type_(type), data_(data)
  {
    /* If there is data, there has to be a type. */
    BLI_assert(data_ == nullptr || type_ != nullptr);
  }
 
  GPointer(const CPPType &type, const void *data = nullptr) : type_(&type), data_(data) {}
 
  template<typename T> GPointer(T *data) : GPointer(&CPPType::get<T>(), data) {}
 
  const void *get() const
  {
    return data_;
  }
 
  const CPPType *type() const
  {
    return type_;
  }
 
  template<typename T> const T *get() const
  {
    BLI_assert(this->is_type<T>());
    return static_cast<const T *>(data_);
  }
 
  template<typename T> bool is_type() const
  {
    return type_ != nullptr && type_->is<T>();
  }
};
 
}  // namespace blender