mirror of https://github.com/facebook/rocksdb.git
86 lines
3.0 KiB
C++
86 lines
3.0 KiB
C++
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
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// This source code is licensed under both the GPLv2 (found in the
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// COPYING file in the root directory) and Apache 2.0 License
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// (found in the LICENSE.Apache file in the root directory).
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//
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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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#pragma once
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#include "table/block_based/block_based_table_reader.h"
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#include "table/block_based/reader_common.h"
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namespace ROCKSDB_NAMESPACE {
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// Encapsulates common functionality for the various index reader
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// implementations. Provides access to the index block regardless of whether
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// it is owned by the reader or stored in the cache, or whether it is pinned
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// in the cache or not.
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class BlockBasedTable::IndexReaderCommon : public BlockBasedTable::IndexReader {
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public:
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IndexReaderCommon(const BlockBasedTable* t,
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CachableEntry<Block>&& index_block)
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: table_(t), index_block_(std::move(index_block)) {
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assert(table_ != nullptr);
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}
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protected:
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static Status ReadIndexBlock(const BlockBasedTable* table,
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FilePrefetchBuffer* prefetch_buffer,
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const ReadOptions& read_options, bool use_cache,
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GetContext* get_context,
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BlockCacheLookupContext* lookup_context,
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CachableEntry<Block>* index_block);
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const BlockBasedTable* table() const { return table_; }
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const InternalKeyComparator* internal_comparator() const {
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assert(table_ != nullptr);
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assert(table_->get_rep() != nullptr);
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return &table_->get_rep()->internal_comparator;
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}
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bool index_has_first_key() const {
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assert(table_ != nullptr);
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assert(table_->get_rep() != nullptr);
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return table_->get_rep()->index_has_first_key;
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}
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bool index_key_includes_seq() const {
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assert(table_ != nullptr);
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assert(table_->get_rep() != nullptr);
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return table_->get_rep()->index_key_includes_seq;
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}
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bool index_value_is_full() const {
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assert(table_ != nullptr);
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assert(table_->get_rep() != nullptr);
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return table_->get_rep()->index_value_is_full;
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}
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bool cache_index_blocks() const {
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assert(table_ != nullptr);
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assert(table_->get_rep() != nullptr);
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return table_->get_rep()->table_options.cache_index_and_filter_blocks;
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}
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Status GetOrReadIndexBlock(bool no_io, GetContext* get_context,
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BlockCacheLookupContext* lookup_context,
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CachableEntry<Block>* index_block) const;
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size_t ApproximateIndexBlockMemoryUsage() const {
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assert(!index_block_.GetOwnValue() || index_block_.GetValue() != nullptr);
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return index_block_.GetOwnValue()
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? index_block_.GetValue()->ApproximateMemoryUsage()
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: 0;
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}
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private:
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const BlockBasedTable* table_;
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CachableEntry<Block> index_block_;
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};
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} // namespace ROCKSDB_NAMESPACE
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