rocksdb/util/compression_context_cache.h
Zhongyi Xie f1592a06c2 run make format for PR 3838 (#3954)
Summary:
PR https://github.com/facebook/rocksdb/pull/3838 made some changes that triggers lint warnings.
Run `make format` to fix formatting as suggested by siying .
Also piggyback two changes:
1) fix singleton destruction order for windows and posix env
2) fix two clang warnings
Closes https://github.com/facebook/rocksdb/pull/3954

Differential Revision: D8272041

Pulled By: miasantreble

fbshipit-source-id: 7c4fd12bd17aac13534520de0c733328aa3c6c9f
2018-06-05 12:58:02 -07:00

46 lines
1.6 KiB
C++

// 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.
//
// Compression context cache allows to cache compression/uncompression contexts
// This helps with Random Read latencies and reduces CPU utilization
// Caching is implemented using CoreLocal facility. Compression/Uncompression
// instances are cached on a per core basis using CoreLocalArray. A borrowed
// instance is atomically replaced with a sentinel value for the time of being
// used. If it turns out that another thread is already makes use of the
// instance we still create one on the heap which is later is destroyed.
#pragma once
#include <stdint.h>
namespace rocksdb {
class ZSTDUncompressCachedData;
class CompressionContextCache {
public:
// Singleton
static CompressionContextCache* Instance();
static void InitSingleton();
CompressionContextCache(const CompressionContextCache&) = delete;
CompressionContextCache& operator=(const CompressionContextCache&) = delete;
ZSTDUncompressCachedData GetCachedZSTDUncompressData();
void ReturnCachedZSTDUncompressData(int64_t idx);
private:
// Singleton
CompressionContextCache();
~CompressionContextCache();
class Rep;
Rep* rep_;
};
} // namespace rocksdb