1 files changed, 64 insertions, 0 deletions
diff --git a/src/rocksdb/util/user_comparator_wrapper.h b/src/rocksdb/util/user_comparator_wrapper.h
new file mode 100644
index 000000000..59ebada12
--- /dev/null
+++ b/src/rocksdb/util/user_comparator_wrapper.h
@@ -0,0 +1,64 @@
+// 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) 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 "monitoring/perf_context_imp.h"
+#include "rocksdb/comparator.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+// Wrapper of user comparator, with auto increment to
+// perf_context.user_key_comparison_count.
+class UserComparatorWrapper {
+ public:
+  // `UserComparatorWrapper`s constructed with the default constructor are not
+  // usable and will segfault on any attempt to use them for comparisons.
+  UserComparatorWrapper() : user_comparator_(nullptr) {}
+
+  explicit UserComparatorWrapper(const Comparator* const user_cmp)
+      : user_comparator_(user_cmp) {}
+
+  ~UserComparatorWrapper() = default;
+
+  const Comparator* user_comparator() const { return user_comparator_; }
+
+  int Compare(const Slice& a, const Slice& b) const {
+    PERF_COUNTER_ADD(user_key_comparison_count, 1);
+    return user_comparator_->Compare(a, b);
+  }
+
+  bool Equal(const Slice& a, const Slice& b) const {
+    PERF_COUNTER_ADD(user_key_comparison_count, 1);
+    return user_comparator_->Equal(a, b);
+  }
+
+  int CompareTimestamp(const Slice& ts1, const Slice& ts2) const {
+    return user_comparator_->CompareTimestamp(ts1, ts2);
+  }
+
+  int CompareWithoutTimestamp(const Slice& a, const Slice& b) const {
+    PERF_COUNTER_ADD(user_key_comparison_count, 1);
+    return user_comparator_->CompareWithoutTimestamp(a, b);
+  }
+
+  int CompareWithoutTimestamp(const Slice& a, bool a_has_ts, const Slice& b,
+                              bool b_has_ts) const {
+    PERF_COUNTER_ADD(user_key_comparison_count, 1);
+    return user_comparator_->CompareWithoutTimestamp(a, a_has_ts, b, b_has_ts);
+  }
+
+  bool EqualWithoutTimestamp(const Slice& a, const Slice& b) const {
+    return user_comparator_->EqualWithoutTimestamp(a, b);
+  }
+
+ private:
+  const Comparator* user_comparator_;
+};
+
+}  // namespace ROCKSDB_NAMESPACE