YugabyteDB (2.13.0.0-b42, bfc6a6643e7399ac8a0e81d06a3ee6d6571b33ab)

//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.

//  This source code is licensed under the BSD-style license found in the

//  LICENSE file in the root directory of this source tree. An additional grant

//  of patent rights can be found in the PATENTS file in the same directory.

//

// The following only applies to changes made to this file as part of YugaByte development.

//

// Portions Copyright (c) YugaByte, Inc.

//

// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except

// in compliance with the License.  You may obtain a copy of the License at

//

// http://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing, software distributed under the License

// is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express

// or implied.  See the License for the specific language governing permissions and limitations

// under the License.

//

#pragma once

#include <stddef.h>

#include <stdint.h>

#include <memory>

#include <string>

#include <vector>

#include "yb/rocksdb/filter_policy.h"

#include "yb/rocksdb/options.h"

#include "yb/rocksdb/slice_transform.h"

#include "yb/rocksdb/table/filter_block.h"

#include "yb/rocksdb/table/format.h"

#include "yb/rocksdb/util/hash.h"

#include "yb/util/slice.h"

namespace rocksdb {

class FilterPolicy;

class FilterBitsBuilder;

class FilterBitsReader;

// A FullFilterBlockBuilder is used to construct a full filter for a

// particular Table.  It generates a single string which is stored as

// a special block in the Table.

// The format of full filter block is:

// +----------------------------------------------------------------+

// |              full filter for all keys in sst file              |

// +----------------------------------------------------------------+

// The full filter can be very large. At the end of it, we put

// num_probes: how many hash functions are used in bloom filter

//

class FullFilterBlockBuilder : public FilterBlockBuilder {

 public:

  explicit FullFilterBlockBuilder(const SliceTransform* prefix_extractor,

                                  bool whole_key_filtering,

                                  FilterBitsBuilder* filter_bits_builder);

  // bits_builder is created in filter_policy, it should be passed in here

  // directly. and be deleted here

  ~FullFilterBlockBuilder() {}

  virtual void StartBlock(uint64_t block_offset) override {}

  virtual void Add(const Slice& key) override;

  virtual Slice Finish() override;

  virtual bool ShouldFlush() const override { return false; }

 private:

  // important: all of these might point to invalid addresses

  // at the time of destruction of this filter block. destructor

  // should NOT dereference them.

  const SliceTransform* prefix_extractor_;

  bool whole_key_filtering_;

  uint32_t num_added_;

  std::unique_ptr<FilterBitsBuilder> filter_bits_builder_;

  std::unique_ptr<const char[]> filter_data_;

  void AddKey(const Slice& key);

  void AddPrefix(const Slice& key);

  // No copying allowed

  FullFilterBlockBuilder(const FullFilterBlockBuilder&);

  void operator=(const FullFilterBlockBuilder&);

};

// A FilterBlockReader is used to parse filter from SST table.

// KeyMayMatch and PrefixMayMatch would trigger filter checking

class FullFilterBlockReader : public FilterBlockReader {

 public:

  // REQUIRES: "contents" and filter_bits_reader must stay live

  // while *this is live.

  explicit FullFilterBlockReader(const SliceTransform* prefix_extractor,

                                 bool whole_key_filtering,

                                 const Slice& contents,

                                 FilterBitsReader* filter_bits_reader);

  explicit FullFilterBlockReader(const SliceTransform* prefix_extractor,

                                 bool whole_key_filtering,

                                 BlockContents&& contents,

                                 FilterBitsReader* filter_bits_reader);

  // bits_reader is created in filter_policy, it should be passed in here

  // directly. and be deleted here

  ~FullFilterBlockReader() {}

  virtual bool KeyMayMatch(const Slice& key,

                           uint64_t block_offset = kNotValid) override;

  virtual bool PrefixMayMatch(const Slice& prefix,

                              uint64_t block_offset = kNotValid) override;

  virtual size_t ApproximateMemoryUsage() const override;

 private:

  const SliceTransform* prefix_extractor_;

  bool whole_key_filtering_;

  std::unique_ptr<FilterBitsReader> filter_bits_reader_;

  Slice contents_;

  BlockContents block_contents_;

  std::unique_ptr<const char[]> filter_data_;

  bool MayMatch(const Slice& entry);

  // No copying allowed

  FullFilterBlockReader(const FullFilterBlockReader&);

  void operator=(const FullFilterBlockReader&);

};

}  // namespace rocksdb