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// 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/block_based_table_reader.h"
#include "table/block_based/reader_common.h"
namespace ROCKSDB_NAMESPACE {
// Encapsulates common functionality for the various index reader
// implementations. Provides access to the index 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.
class BlockBasedTable::IndexReaderCommon : public BlockBasedTable::IndexReader {
public:
IndexReaderCommon(const BlockBasedTable* t,
CachableEntry<Block>&& index_block)
: table_(t), index_block_(std::move(index_block)) {
assert(table_ != nullptr);
}
protected:
static Status ReadIndexBlock(const BlockBasedTable* table,
FilePrefetchBuffer* prefetch_buffer,
const ReadOptions& read_options, bool use_cache,
GetContext* get_context,
BlockCacheLookupContext* lookup_context,
CachableEntry<Block>* index_block);
const BlockBasedTable* table() const { return table_; }
const InternalKeyComparator* internal_comparator() const {
assert(table_ != nullptr);
assert(table_->get_rep() != nullptr);
return &table_->get_rep()->internal_comparator;
}
bool index_has_first_key() const {
assert(table_ != nullptr);
assert(table_->get_rep() != nullptr);
return table_->get_rep()->index_has_first_key;
}
bool index_key_includes_seq() const {
assert(table_ != nullptr);
assert(table_->get_rep() != nullptr);
return table_->get_rep()->index_key_includes_seq;
}
bool index_value_is_full() const {
assert(table_ != nullptr);
assert(table_->get_rep() != nullptr);
return table_->get_rep()->index_value_is_full;
}
bool cache_index_blocks() const {
assert(table_ != nullptr);
assert(table_->get_rep() != nullptr);
return table_->get_rep()->table_options.cache_index_and_filter_blocks;
}
Status GetOrReadIndexBlock(bool no_io, Env::IOPriority rate_limiter_priority,
GetContext* get_context,
BlockCacheLookupContext* lookup_context,
CachableEntry<Block>* index_block) const;
size_t ApproximateIndexBlockMemoryUsage() const {
assert(!index_block_.GetOwnValue() || index_block_.GetValue() != nullptr);
return index_block_.GetOwnValue()
? index_block_.GetValue()->ApproximateMemoryUsage()
: 0;
}
private:
const BlockBasedTable* table_;
CachableEntry<Block> index_block_;
};
} // namespace ROCKSDB_NAMESPACE
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