fork of https://github.com/oxigraph/rocksdb and https://github.com/facebook/rocksdb for nextgraph and oxigraph
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101 lines
4.1 KiB
101 lines
4.1 KiB
// 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 <vector>
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#include <stdint.h>
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#include "rocksdb/slice.h"
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#include "rocksdb/table.h"
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#include "table/block_based/data_block_hash_index.h"
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namespace ROCKSDB_NAMESPACE {
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class BlockBuilder {
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public:
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BlockBuilder(const BlockBuilder&) = delete;
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void operator=(const BlockBuilder&) = delete;
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explicit BlockBuilder(int block_restart_interval,
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bool use_delta_encoding = true,
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bool use_value_delta_encoding = false,
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BlockBasedTableOptions::DataBlockIndexType index_type =
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BlockBasedTableOptions::kDataBlockBinarySearch,
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double data_block_hash_table_util_ratio = 0.75);
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// Reset the contents as if the BlockBuilder was just constructed.
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void Reset();
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// Swap the contents in BlockBuilder with buffer, then reset the BlockBuilder.
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void SwapAndReset(std::string& buffer);
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// REQUIRES: Finish() has not been called since the last call to Reset().
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// REQUIRES: key is larger than any previously added key
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// DO NOT mix with AddWithLastKey() between Resets. For efficiency, use
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// AddWithLastKey() in contexts where previous added key is already known
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// and delta encoding might be used.
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void Add(const Slice& key, const Slice& value,
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const Slice* const delta_value = nullptr);
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// A faster version of Add() if the previous key is already known for all
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// Add()s.
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// REQUIRES: Finish() has not been called since the last call to Reset().
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// REQUIRES: key is larger than any previously added key
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// REQUIRES: if AddWithLastKey has been called since last Reset(), last_key
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// is the key from most recent AddWithLastKey. (For convenience, last_key
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// is ignored on first call after creation or Reset().)
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// DO NOT mix with Add() between Resets.
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void AddWithLastKey(const Slice& key, const Slice& value,
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const Slice& last_key,
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const Slice* const delta_value = nullptr);
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// Finish building the block and return a slice that refers to the
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// block contents. The returned slice will remain valid for the
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// lifetime of this builder or until Reset() is called.
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Slice Finish();
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// Returns an estimate of the current (uncompressed) size of the block
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// we are building.
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inline size_t CurrentSizeEstimate() const {
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return estimate_ + (data_block_hash_index_builder_.Valid()
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? data_block_hash_index_builder_.EstimateSize()
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: 0);
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}
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// Returns an estimated block size after appending key and value.
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size_t EstimateSizeAfterKV(const Slice& key, const Slice& value) const;
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// Return true iff no entries have been added since the last Reset()
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bool empty() const { return buffer_.empty(); }
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private:
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inline void AddWithLastKeyImpl(const Slice& key, const Slice& value,
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const Slice& last_key,
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const Slice* const delta_value,
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size_t buffer_size);
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const int block_restart_interval_;
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// TODO(myabandeh): put it into a separate IndexBlockBuilder
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const bool use_delta_encoding_;
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// Refer to BlockIter::DecodeCurrentValue for format of delta encoded values
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const bool use_value_delta_encoding_;
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std::string buffer_; // Destination buffer
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std::vector<uint32_t> restarts_; // Restart points
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size_t estimate_;
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int counter_; // Number of entries emitted since restart
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bool finished_; // Has Finish() been called?
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std::string last_key_;
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DataBlockHashIndexBuilder data_block_hash_index_builder_;
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#ifndef NDEBUG
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bool add_with_last_key_called_ = false;
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#endif
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};
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} // namespace ROCKSDB_NAMESPACE
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