mirror of https://github.com/facebook/rocksdb.git
50 lines
1.9 KiB
C++
50 lines
1.9 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.
|
|
#pragma once
|
|
|
|
#include "table/block_based/index_reader_common.h"
|
|
|
|
namespace ROCKSDB_NAMESPACE {
|
|
// Index that leverages an internal hash table to quicken the lookup for a given
|
|
// key.
|
|
class HashIndexReader : public BlockBasedTable::IndexReaderCommon {
|
|
public:
|
|
static Status Create(const BlockBasedTable* table,
|
|
FilePrefetchBuffer* prefetch_buffer,
|
|
InternalIterator* meta_index_iter, bool use_cache,
|
|
bool prefetch, bool pin,
|
|
BlockCacheLookupContext* lookup_context,
|
|
std::unique_ptr<IndexReader>* index_reader);
|
|
|
|
InternalIteratorBase<IndexValue>* NewIterator(
|
|
const ReadOptions& read_options, bool disable_prefix_seek,
|
|
IndexBlockIter* iter, GetContext* get_context,
|
|
BlockCacheLookupContext* lookup_context) override;
|
|
|
|
size_t ApproximateMemoryUsage() const override {
|
|
size_t usage = ApproximateIndexBlockMemoryUsage();
|
|
#ifdef ROCKSDB_MALLOC_USABLE_SIZE
|
|
usage += malloc_usable_size(const_cast<HashIndexReader*>(this));
|
|
#else
|
|
if (prefix_index_) {
|
|
usage += prefix_index_->ApproximateMemoryUsage();
|
|
}
|
|
usage += sizeof(*this);
|
|
#endif // ROCKSDB_MALLOC_USABLE_SIZE
|
|
return usage;
|
|
}
|
|
|
|
private:
|
|
HashIndexReader(const BlockBasedTable* t, CachableEntry<Block>&& index_block)
|
|
: IndexReaderCommon(t, std::move(index_block)) {}
|
|
|
|
std::unique_ptr<BlockPrefixIndex> prefix_index_;
|
|
};
|
|
} // namespace ROCKSDB_NAMESPACE
|