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rust-rocksdb/util/concurrent_task_limiter_impl.h

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// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
//
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#pragma once
#include <atomic>
#include <memory>
#include "rocksdb/concurrent_task_limiter.h"
#include "rocksdb/env.h"
namespace ROCKSDB_NAMESPACE {
class TaskLimiterToken;
class ConcurrentTaskLimiterImpl : public ConcurrentTaskLimiter {
public:
explicit ConcurrentTaskLimiterImpl(const std::string& name,
int32_t max_outstanding_task);
// No copying allowed
ConcurrentTaskLimiterImpl(const ConcurrentTaskLimiterImpl&) = delete;
ConcurrentTaskLimiterImpl& operator=(const ConcurrentTaskLimiterImpl&) =
delete;
virtual ~ConcurrentTaskLimiterImpl();
virtual const std::string& GetName() const override;
virtual void SetMaxOutstandingTask(int32_t limit) override;
virtual void ResetMaxOutstandingTask() override;
virtual int32_t GetOutstandingTask() const override;
// Request token for adding a new task.
// If force == true, it requests a token bypassing throttle.
// Returns nullptr if it got throttled.
virtual std::unique_ptr<TaskLimiterToken> GetToken(bool force);
private:
friend class TaskLimiterToken;
std::string name_;
std::atomic<int32_t> max_outstanding_tasks_;
std::atomic<int32_t> outstanding_tasks_;
};
class TaskLimiterToken {
public:
explicit TaskLimiterToken(ConcurrentTaskLimiterImpl* limiter)
: limiter_(limiter) {}
~TaskLimiterToken();
private:
ConcurrentTaskLimiterImpl* limiter_;
// no copying allowed
TaskLimiterToken(const TaskLimiterToken&) = delete;
void operator=(const TaskLimiterToken&) = delete;
};
} // namespace ROCKSDB_NAMESPACE