xref: /base/usb/usb_manager/utils/native/include/delayed_sp_singleton.h

/*
 * Copyright (c) 2021-2022 Huawei Device Co., Ltd.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef DELAYED_SP_SINGLETON_H
#define DELAYED_SP_SINGLETON_H

#include <memory>
#include <mutex>
#include <refbase.h>
#include "nocopyable.h"
#include "hilog_wrapper.h"

namespace OHOS {
namespace USB {
#define DECLARE_DELAYED_SP_SINGLETON(MyClass) \
public:                                       \
    ~MyClass();                               \
                                              \
private:                                      \
    friend DelayedSpSingleton<MyClass>;       \
    MyClass()

template <typename T> class DelayedSpSingleton : public NoCopyable {
public:
    static sptr<T> GetInstance();
    static void DestroyInstance();

private:
    static sptr<T> instance_;
    static std::mutex mutex_;
};

template <typename T> sptr<T> DelayedSpSingleton<T>::instance_ = nullptr;

template <typename T> std::mutex DelayedSpSingleton<T>::mutex_;

template <typename T> sptr<T> DelayedSpSingleton<T>::GetInstance()
{
    if (instance_ != nullptr) {
        return instance_;
    }

    std::lock_guard<std::mutex> lock(mutex_);
    if (instance_ == nullptr) {
        instance_ = new(std::nothrow) T();
        if (instance_ == nullptr) {
            USB_HILOGI(MODULE_USB_SERVICE, "get instance failed\n");
        }
    }

    return instance_;
}

template <typename T> void DelayedSpSingleton<T>::DestroyInstance()
{
    std::lock_guard<std::mutex> lock(mutex_);
    if (instance_) {
        instance_.clear();
        instance_ = nullptr;
    }
}
} // namespace USB
} // namespace OHOS
#endif // DELAYED_SP_SINGLETON_H