1 files changed, 41 insertions, 0 deletions
diff --git a/src/rocksdb/utilities/compaction_filters/layered_compaction_filter_base.h b/src/rocksdb/utilities/compaction_filters/layered_compaction_filter_base.h
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index 000000000..803fa94ae
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+++ b/src/rocksdb/utilities/compaction_filters/layered_compaction_filter_base.h
@@ -0,0 +1,41 @@
+// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+// Copyright (c) 2011 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.
+
+#pragma once
+#include <memory>
+
+#include "rocksdb/compaction_filter.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+// Abstract base class for building layered compaction filter on top of
+// user compaction filter.
+// See BlobIndexCompactionFilter or TtlCompactionFilter for a basic usage.
+class LayeredCompactionFilterBase : public CompactionFilter {
+ public:
+  LayeredCompactionFilterBase(
+      const CompactionFilter* _user_comp_filter,
+      std::unique_ptr<const CompactionFilter> _user_comp_filter_from_factory)
+      : user_comp_filter_(_user_comp_filter),
+        user_comp_filter_from_factory_(
+            std::move(_user_comp_filter_from_factory)) {
+    if (!user_comp_filter_) {
+      user_comp_filter_ = user_comp_filter_from_factory_.get();
+    }
+  }
+
+  // Return a pointer to user compaction filter
+  const CompactionFilter* user_comp_filter() const { return user_comp_filter_; }
+
+  const Customizable* Inner() const override { return user_comp_filter_; }
+
+ protected:
+  const CompactionFilter* user_comp_filter_;
+
+ private:
+  std::unique_ptr<const CompactionFilter> user_comp_filter_from_factory_;
+};
+
+}  //  namespace ROCKSDB_NAMESPACE