1 files changed, 79 insertions, 0 deletions
diff --git a/src/rocksdb/table/block_based/filter_block_reader_common.h b/src/rocksdb/table/block_based/filter_block_reader_common.h
new file mode 100644
index 000000000..ca07f5050
--- /dev/null
+++ b/src/rocksdb/table/block_based/filter_block_reader_common.h
@@ -0,0 +1,79 @@
+//  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).
+//
+
+#pragma once
+
+#include <cassert>
+
+#include "block_type.h"
+#include "table/block_based/cachable_entry.h"
+#include "table/block_based/filter_block.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+class BlockBasedTable;
+class FilePrefetchBuffer;
+
+// Encapsulates common functionality for the various filter block reader
+// implementations. Provides access to the filter 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.
+template <typename TBlocklike>
+class FilterBlockReaderCommon : public FilterBlockReader {
+ public:
+  FilterBlockReaderCommon(const BlockBasedTable* t,
+                          CachableEntry<TBlocklike>&& filter_block)
+      : table_(t), filter_block_(std::move(filter_block)) {
+    assert(table_);
+    const SliceTransform* const prefix_extractor = table_prefix_extractor();
+    if (prefix_extractor) {
+      full_length_enabled_ =
+          prefix_extractor->FullLengthEnabled(&prefix_extractor_full_length_);
+    }
+  }
+
+  bool RangeMayExist(const Slice* iterate_upper_bound, const Slice& user_key,
+                     const SliceTransform* prefix_extractor,
+                     const Comparator* comparator,
+                     const Slice* const const_ikey_ptr, bool* filter_checked,
+                     bool need_upper_bound_check, bool no_io,
+                     BlockCacheLookupContext* lookup_context,
+                     Env::IOPriority rate_limiter_priority) override;
+
+ protected:
+  static Status ReadFilterBlock(const BlockBasedTable* table,
+                                FilePrefetchBuffer* prefetch_buffer,
+                                const ReadOptions& read_options, bool use_cache,
+                                GetContext* get_context,
+                                BlockCacheLookupContext* lookup_context,
+                                CachableEntry<TBlocklike>* filter_block,
+                                BlockType block_type);
+
+  const BlockBasedTable* table() const { return table_; }
+  const SliceTransform* table_prefix_extractor() const;
+  bool whole_key_filtering() const;
+  bool cache_filter_blocks() const;
+
+  Status GetOrReadFilterBlock(bool no_io, GetContext* get_context,
+                              BlockCacheLookupContext* lookup_context,
+                              CachableEntry<TBlocklike>* filter_block,
+                              BlockType block_type,
+                              Env::IOPriority rate_limiter_priority) const;
+
+  size_t ApproximateFilterBlockMemoryUsage() const;
+
+ private:
+  bool IsFilterCompatible(const Slice* iterate_upper_bound, const Slice& prefix,
+                          const Comparator* comparator) const;
+
+ private:
+  const BlockBasedTable* table_;
+  CachableEntry<TBlocklike> filter_block_;
+  size_t prefix_extractor_full_length_ = 0;
+  bool full_length_enabled_ = false;
+};
+
+}  // namespace ROCKSDB_NAMESPACE