ceph/src/rocksdb/table/block_based/binary_search_index_reader.cc

   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 // Copyright (c) 2011 The LevelDB Authors. All rights reserved.
   7 // Use of this source code is governed by a BSD-style license that can be
   8 // found in the LICENSE file. See the AUTHORS file for names of contributors.
   9 #include "table/block_based/binary_search_index_reader.h"
  10
  11 namespace ROCKSDB_NAMESPACE {
  12 Status BinarySearchIndexReader::Create(
  13     const BlockBasedTable* table, const ReadOptions& ro,
  14     FilePrefetchBuffer* prefetch_buffer, bool use_cache, bool prefetch,
  15     bool pin, BlockCacheLookupContext* lookup_context,
  16     std::unique_ptr<IndexReader>* index_reader) {
  17   assert(table != nullptr);
  18   assert(table->get_rep());
  19   assert(!pin || prefetch);
  20   assert(index_reader != nullptr);
  21
  22   CachableEntry<Block> index_block;
  23   if (prefetch || !use_cache) {
  24     const Status s =
  25         ReadIndexBlock(table, prefetch_buffer, ro, use_cache,
  26                        /*get_context=*/nullptr, lookup_context, &index_block);
  27     if (!s.ok()) {
  28       return s;
  29     }
  30
  31     if (use_cache && !pin) {
  32       index_block.Reset();
  33     }
  34   }
  35
  36   index_reader->reset(
  37       new BinarySearchIndexReader(table, std::move(index_block)));
  38
  39   return Status::OK();
  40 }
  41
  42 InternalIteratorBase<IndexValue>* BinarySearchIndexReader::NewIterator(
  43     const ReadOptions& read_options, bool /* disable_prefix_seek */,
  44     IndexBlockIter* iter, GetContext* get_context,
  45     BlockCacheLookupContext* lookup_context) {
  46   const BlockBasedTable::Rep* rep = table()->get_rep();
  47   const bool no_io = (read_options.read_tier == kBlockCacheTier);
  48   CachableEntry<Block> index_block;
  49   const Status s =
  50       GetOrReadIndexBlock(no_io, read_options.rate_limiter_priority,
  51                           get_context, lookup_context, &index_block);
  52   if (!s.ok()) {
  53     if (iter != nullptr) {
  54       iter->Invalidate(s);
  55       return iter;
  56     }
  57
  58     return NewErrorInternalIterator<IndexValue>(s);
  59   }
  60
  61   Statistics* kNullStats = nullptr;
  62   // We don't return pinned data from index blocks, so no need
  63   // to set `block_contents_pinned`.
  64   auto it = index_block.GetValue()->NewIndexIterator(
  65       internal_comparator()->user_comparator(),
  66       rep->get_global_seqno(BlockType::kIndex), iter, kNullStats, true,
  67       index_has_first_key(), index_key_includes_seq(), index_value_is_full());
  68
  69   assert(it != nullptr);
  70   index_block.TransferTo(it);
  71
  72   return it;
  73 }
  74 }  // namespace ROCKSDB_NAMESPACE