ceph/src/rocksdb/table/persistent_cache_helper.h

   1 //  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
   2 //  This source code is licensed under both the GPLv2 (found in the
   3 //  COPYING file in the root directory) and Apache 2.0 License
   4 //  (found in the LICENSE.Apache file in the root directory).
   5 #pragma once
   6
   7 #include <string>
   8
   9 #include "monitoring/statistics.h"
  10 #include "table/format.h"
  11 #include "table/persistent_cache_options.h"
  12
  13 namespace ROCKSDB_NAMESPACE {
  14
  15 struct BlockContents;
  16
  17 // PersistentCacheHelper
  18 //
  19 // Encapsulates  some of the helper logic for read and writing from the cache
  20 class PersistentCacheHelper {
  21  public:
  22   // Insert block into cache of serialized blocks. Size includes block trailer
  23   // (if applicable).
  24   static void InsertSerialized(const PersistentCacheOptions& cache_options,
  25                                const BlockHandle& handle, const char* data,
  26                                const size_t size);
  27
  28   // Insert block into cache of uncompressed blocks. No block trailer.
  29   static void InsertUncompressed(const PersistentCacheOptions& cache_options,
  30                                  const BlockHandle& handle,
  31                                  const BlockContents& contents);
  32
  33   // Lookup block from cache of serialized blocks. Size includes block trailer
  34   // (if applicable).
  35   static Status LookupSerialized(const PersistentCacheOptions& cache_options,
  36                                  const BlockHandle& handle,
  37                                  std::unique_ptr<char[]>* out_data,
  38                                  const size_t expected_data_size);
  39
  40   // Lookup block from uncompressed cache. No block trailer.
  41   static Status LookupUncompressed(const PersistentCacheOptions& cache_options,
  42                                    const BlockHandle& handle,
  43                                    BlockContents* contents);
  44 };
  45
  46 }  // namespace ROCKSDB_NAMESPACE