ceph/src/rocksdb/db/blob/blob_file_cache.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
   6 #pragma once
   7
   8 #include <cinttypes>
   9
  10 #include "cache/cache_helpers.h"
  11 #include "rocksdb/rocksdb_namespace.h"
  12 #include "util/mutexlock.h"
  13
  14 namespace ROCKSDB_NAMESPACE {
  15
  16 class Cache;
  17 struct ImmutableCFOptions;
  18 struct FileOptions;
  19 class HistogramImpl;
  20 class Status;
  21 class BlobFileReader;
  22 class Slice;
  23
  24 class BlobFileCache {
  25  public:
  26   BlobFileCache(Cache* cache, const ImmutableCFOptions* immutable_cf_options,
  27                 const FileOptions* file_options, uint32_t column_family_id,
  28                 HistogramImpl* blob_file_read_hist);
  29
  30   BlobFileCache(const BlobFileCache&) = delete;
  31   BlobFileCache& operator=(const BlobFileCache&) = delete;
  32
  33   Status GetBlobFileReader(uint64_t blob_file_number,
  34                            CacheHandleGuard<BlobFileReader>* blob_file_reader);
  35
  36  private:
  37   Cache* cache_;
  38   // Note: mutex_ below is used to guard against multiple threads racing to open
  39   // the same file.
  40   Striped<port::Mutex, Slice> mutex_;
  41   const ImmutableCFOptions* immutable_cf_options_;
  42   const FileOptions* file_options_;
  43   uint32_t column_family_id_;
  44   HistogramImpl* blob_file_read_hist_;
  45
  46   static constexpr size_t kNumberOfMutexStripes = 1 << 7;
  47 };
  48
  49 }  // namespace ROCKSDB_NAMESPACE