1 files changed, 59 insertions, 0 deletions
diff --git a/src/rocksdb/table/block_based/uncompression_dict_reader.h b/src/rocksdb/table/block_based/uncompression_dict_reader.h
new file mode 100644
index 000000000..3e7826179
--- /dev/null
+++ b/src/rocksdb/table/block_based/uncompression_dict_reader.h
@@ -0,0 +1,59 @@
+//  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 "table/block_based/cachable_entry.h"
+#include "table/format.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+class BlockBasedTable;
+struct BlockCacheLookupContext;
+class FilePrefetchBuffer;
+class GetContext;
+struct ReadOptions;
+struct UncompressionDict;
+
+// Provides access to the uncompression dictionary regardless of whether
+// it is owned by the reader or stored in the cache, or whether it is pinned
+// in the cache or not.
+class UncompressionDictReader {
+ public:
+  static Status Create(
+      const BlockBasedTable* table, FilePrefetchBuffer* prefetch_buffer,
+      bool use_cache, bool prefetch, bool pin,
+      BlockCacheLookupContext* lookup_context,
+      std::unique_ptr<UncompressionDictReader>* uncompression_dict_reader);
+
+  Status GetOrReadUncompressionDictionary(
+      FilePrefetchBuffer* prefetch_buffer, bool no_io, GetContext* get_context,
+      BlockCacheLookupContext* lookup_context,
+      CachableEntry<UncompressionDict>* uncompression_dict) const;
+
+  size_t ApproximateMemoryUsage() const;
+
+ private:
+  UncompressionDictReader(const BlockBasedTable* t,
+                          CachableEntry<UncompressionDict>&& uncompression_dict)
+      : table_(t), uncompression_dict_(std::move(uncompression_dict)) {
+    assert(table_);
+  }
+
+  bool cache_dictionary_blocks() const;
+
+  static Status ReadUncompressionDictionary(
+      const BlockBasedTable* table, FilePrefetchBuffer* prefetch_buffer,
+      const ReadOptions& read_options, bool use_cache, GetContext* get_context,
+      BlockCacheLookupContext* lookup_context,
+      CachableEntry<UncompressionDict>* uncompression_dict);
+
+  const BlockBasedTable* table_;
+  CachableEntry<UncompressionDict> uncompression_dict_;
+};
+
+}  // namespace ROCKSDB_NAMESPACE