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Diffstat (limited to 'source/blender/blenlib/BLI_user_counter.hh')
-rw-r--r-- | source/blender/blenlib/BLI_user_counter.hh | 158 |
1 files changed, 158 insertions, 0 deletions
diff --git a/source/blender/blenlib/BLI_user_counter.hh b/source/blender/blenlib/BLI_user_counter.hh new file mode 100644 index 00000000000..ef276814981 --- /dev/null +++ b/source/blender/blenlib/BLI_user_counter.hh @@ -0,0 +1,158 @@ +/* + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software Foundation, + * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + */ + +#pragma once + +/** \file + * \ingroup bli + */ + +#include <atomic> + +namespace blender { + +/** + * A simple automatic reference counter. It is similar to std::shared_ptr, but expects that the + * reference count is inside the object. + */ +template<typename T> class UserCounter { + private: + T *data_ = nullptr; + + public: + UserCounter() = default; + + UserCounter(T *data) : data_(data) + { + } + + UserCounter(const UserCounter &other) : data_(other.data_) + { + this->user_add(data_); + } + + UserCounter(UserCounter &&other) : data_(other.data_) + { + other.data_ = nullptr; + } + + ~UserCounter() + { + this->user_remove(data_); + } + + UserCounter &operator=(const UserCounter &other) + { + if (this == &other) { + return *this; + } + + this->user_remove(data_); + data_ = other.data_; + this->user_add(data_); + return *this; + } + + UserCounter &operator=(UserCounter &&other) + { + if (this == &other) { + return *this; + } + + this->user_remove(data_); + data_ = other.data_; + other.data_ = nullptr; + return *this; + } + + T *operator->() + { + BLI_assert(data_ != nullptr); + return data_; + } + + T &operator*() + { + BLI_assert(data_ != nullptr); + return *data_; + } + + operator bool() const + { + return data_ != nullptr; + } + + T *get() + { + return data_; + } + + const T *get() const + { + return data_; + } + + T *release() + { + T *data = data_; + data_ = nullptr; + return data; + } + + void reset() + { + this->user_remove(data_); + data_ = nullptr; + } + + bool has_value() const + { + return data_ != nullptr; + } + + uint64_t hash() const + { + return DefaultHash<T *>{}(data_); + } + + friend bool operator==(const UserCounter &a, const UserCounter &b) + { + return a.data_ == b.data_; + } + + friend std::ostream &operator<<(std::ostream &stream, const UserCounter &value) + { + stream << value.data_; + return stream; + } + + private: + static void user_add(T *data) + { + if (data != nullptr) { + data->user_add(); + } + } + + static void user_remove(T *data) + { + if (data != nullptr) { + data->user_remove(); + } + } +}; + +} // namespace blender |