1 files changed, 119 insertions, 0 deletions
diff --git a/src/rocksdb/table/block_based/block_based_filter_block.h b/src/rocksdb/table/block_based/block_based_filter_block.h
new file mode 100644
index 000000000..01c98a70b
--- /dev/null
+++ b/src/rocksdb/table/block_based/block_based_filter_block.h
@@ -0,0 +1,119 @@
+//  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) 2012 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.
+//
+// A filter block is stored near the end of a Table file.  It contains
+// filters (e.g., bloom filters) for all data blocks in the table combined
+// into a single filter block.
+
+#pragma once
+
+#include <stddef.h>
+#include <stdint.h>
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "rocksdb/options.h"
+#include "rocksdb/slice.h"
+#include "rocksdb/slice_transform.h"
+#include "table/block_based/filter_block_reader_common.h"
+#include "table/format.h"
+#include "util/hash.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+// A BlockBasedFilterBlockBuilder is used to construct all of the filters for a
+// particular Table.  It generates a single string which is stored as
+// a special block in the Table.
+//
+// The sequence of calls to BlockBasedFilterBlockBuilder must match the regexp:
+//      (StartBlock Add*)* Finish
+class BlockBasedFilterBlockBuilder : public FilterBlockBuilder {
+ public:
+  BlockBasedFilterBlockBuilder(const SliceTransform* prefix_extractor,
+                               const BlockBasedTableOptions& table_opt);
+  // No copying allowed
+  BlockBasedFilterBlockBuilder(const BlockBasedFilterBlockBuilder&) = delete;
+  void operator=(const BlockBasedFilterBlockBuilder&) = delete;
+
+  virtual bool IsBlockBased() override { return true; }
+  virtual void StartBlock(uint64_t block_offset) override;
+  virtual void Add(const Slice& key) override;
+  virtual size_t NumAdded() const override { return num_added_; }
+  virtual Slice Finish(const BlockHandle& tmp, Status* status) override;
+  using FilterBlockBuilder::Finish;
+
+ private:
+  void AddKey(const Slice& key);
+  void AddPrefix(const Slice& key);
+  void GenerateFilter();
+
+  // important: all of these might point to invalid addresses
+  // at the time of destruction of this filter block. destructor
+  // should NOT dereference them.
+  const FilterPolicy* policy_;
+  const SliceTransform* prefix_extractor_;
+  bool whole_key_filtering_;
+
+  size_t prev_prefix_start_;        // the position of the last appended prefix
+                                    // to "entries_".
+  size_t prev_prefix_size_;         // the length of the last appended prefix to
+                                    // "entries_".
+  std::string entries_;             // Flattened entry contents
+  std::vector<size_t> start_;       // Starting index in entries_ of each entry
+  std::string result_;              // Filter data computed so far
+  std::vector<Slice> tmp_entries_;  // policy_->CreateFilter() argument
+  std::vector<uint32_t> filter_offsets_;
+  size_t num_added_;  // Number of keys added
+};
+
+// A FilterBlockReader is used to parse filter from SST table.
+// KeyMayMatch and PrefixMayMatch would trigger filter checking
+class BlockBasedFilterBlockReader
+    : public FilterBlockReaderCommon<BlockContents> {
+ public:
+  BlockBasedFilterBlockReader(const BlockBasedTable* t,
+                              CachableEntry<BlockContents>&& filter_block);
+  // No copying allowed
+  BlockBasedFilterBlockReader(const BlockBasedFilterBlockReader&) = delete;
+  void operator=(const BlockBasedFilterBlockReader&) = delete;
+
+  static std::unique_ptr<FilterBlockReader> Create(
+      const BlockBasedTable* table, FilePrefetchBuffer* prefetch_buffer,
+      bool use_cache, bool prefetch, bool pin,
+      BlockCacheLookupContext* lookup_context);
+
+  bool IsBlockBased() override { return true; }
+
+  bool KeyMayMatch(const Slice& key, const SliceTransform* prefix_extractor,
+                   uint64_t block_offset, const bool no_io,
+                   const Slice* const const_ikey_ptr, GetContext* get_context,
+                   BlockCacheLookupContext* lookup_context) override;
+  bool PrefixMayMatch(const Slice& prefix,
+                      const SliceTransform* prefix_extractor,
+                      uint64_t block_offset, const bool no_io,
+                      const Slice* const const_ikey_ptr,
+                      GetContext* get_context,
+                      BlockCacheLookupContext* lookup_context) override;
+  size_t ApproximateMemoryUsage() const override;
+
+  // convert this object to a human readable form
+  std::string ToString() const override;
+
+ private:
+  static bool ParseFieldsFromBlock(const BlockContents& contents,
+                                   const char** data, const char** offset,
+                                   size_t* num, size_t* base_lg);
+
+  bool MayMatch(const Slice& entry, uint64_t block_offset, bool no_io,
+                GetContext* get_context,
+                BlockCacheLookupContext* lookup_context) const;
+};
+
+}  // namespace ROCKSDB_NAMESPACE