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Diffstat (limited to 'source/blender/blenlib/BLI_user_counter.hh')
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diff --git a/source/blender/blenlib/BLI_user_counter.hh b/source/blender/blenlib/BLI_user_counter.hh
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+/*
+ * 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