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rocksdb/table/block_based/filter_block_reader_common.h

55 lines
2.0 KiB

// 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).
//
#pragma once
#include <cassert>
#include "table/block_based/cachable_entry.h"
#include "table/block_based/filter_block.h"
namespace ROCKSDB_NAMESPACE {
class BlockBasedTable;
class FilePrefetchBuffer;
// Encapsulates common functionality for the various filter block reader
// implementations. Provides access to the filter block regardless of whether
// it is owned by the reader or stored in the cache, or whether it is pinned
// in the cache or not.
template <typename TBlocklike>
class FilterBlockReaderCommon : public FilterBlockReader {
public:
FilterBlockReaderCommon(const BlockBasedTable* t,
CachableEntry<TBlocklike>&& filter_block)
: table_(t), filter_block_(std::move(filter_block)) {
assert(table_);
}
protected:
static Status ReadFilterBlock(const BlockBasedTable* table,
FilePrefetchBuffer* prefetch_buffer,
const ReadOptions& read_options, bool use_cache,
GetContext* get_context,
BlockCacheLookupContext* lookup_context,
CachableEntry<TBlocklike>* filter_block);
const BlockBasedTable* table() const { return table_; }
const SliceTransform* table_prefix_extractor() const;
bool whole_key_filtering() const;
bool cache_filter_blocks() const;
Status GetOrReadFilterBlock(bool no_io, GetContext* get_context,
BlockCacheLookupContext* lookup_context,
CachableEntry<TBlocklike>* filter_block) const;
size_t ApproximateFilterBlockMemoryUsage() const;
private:
const BlockBasedTable* table_;
CachableEntry<TBlocklike> filter_block_;
};
} // namespace ROCKSDB_NAMESPACE