rocksdb/table/persistent_cache_helper.h

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// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same directory.
#pragma once
#include <string>
#include "table/block_based_table_reader.h"
#include "util/statistics.h"
namespace rocksdb {
struct BlockContents;
// PersistentCacheOptions
//
// This describe the caching behavior for page cache
// This is used to pass the context for caching and the cache handle
struct PersistentCacheOptions {
PersistentCacheOptions() {}
explicit PersistentCacheOptions(
const std::shared_ptr<PersistentCache>& _persistent_cache,
const std::string _key_prefix, Statistics* const _statistics)
: persistent_cache(_persistent_cache),
key_prefix(_key_prefix),
statistics(_statistics) {}
virtual ~PersistentCacheOptions() {}
std::shared_ptr<PersistentCache> persistent_cache;
std::string key_prefix;
Statistics* statistics = nullptr;
};
// PersistentCacheHelper
//
// Encapsulates some of the helper logic for read and writing from the cache
class PersistentCacheHelper {
public:
// insert block into raw page cache
static void InsertRawPage(const PersistentCacheOptions& cache_options,
const BlockHandle& handle, const char* data,
const size_t size);
// insert block into uncompressed cache
static void InsertUncompressedPage(
const PersistentCacheOptions& cache_options, const BlockHandle& handle,
const BlockContents& contents);
// lookup block from raw page cacge
static Status LookupRawPage(const PersistentCacheOptions& cache_options,
const BlockHandle& handle,
std::unique_ptr<char[]>* raw_data,
const size_t raw_data_size);
// lookup block from uncompressed cache
static Status LookupUncompressedPage(
const PersistentCacheOptions& cache_options, const BlockHandle& handle,
BlockContents* contents);
};
} // namespace rocksdb