From e6918187568dbd01842d8d1d2c808ce16a894239 Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Sun, 21 Apr 2024 13:54:28 +0200
Subject: Adding upstream version 18.2.2.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 src/rocksdb/utilities/merge_operators/put.cc | 92 ++++++++++++++++++++++++++++
 1 file changed, 92 insertions(+)
 create mode 100644 src/rocksdb/utilities/merge_operators/put.cc

(limited to 'src/rocksdb/utilities/merge_operators/put.cc')

diff --git a/src/rocksdb/utilities/merge_operators/put.cc b/src/rocksdb/utilities/merge_operators/put.cc
new file mode 100644
index 000000000..ccf9ff21f
--- /dev/null
+++ b/src/rocksdb/utilities/merge_operators/put.cc
@@ -0,0 +1,92 @@
+//  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).
+
+#include <memory>
+
+#include "rocksdb/merge_operator.h"
+#include "rocksdb/slice.h"
+#include "utilities/merge_operators.h"
+
+namespace {  // anonymous namespace
+
+using ROCKSDB_NAMESPACE::Logger;
+using ROCKSDB_NAMESPACE::MergeOperator;
+using ROCKSDB_NAMESPACE::Slice;
+
+// A merge operator that mimics Put semantics
+// Since this merge-operator will not be used in production,
+// it is implemented as a non-associative merge operator to illustrate the
+// new interface and for testing purposes. (That is, we inherit from
+// the MergeOperator class rather than the AssociativeMergeOperator
+// which would be simpler in this case).
+//
+// From the client-perspective, semantics are the same.
+class PutOperator : public MergeOperator {
+ public:
+  bool FullMerge(const Slice& /*key*/, const Slice* /*existing_value*/,
+                 const std::deque<std::string>& operand_sequence,
+                 std::string* new_value, Logger* /*logger*/) const override {
+    // Put basically only looks at the current/latest value
+    assert(!operand_sequence.empty());
+    assert(new_value != nullptr);
+    new_value->assign(operand_sequence.back());
+    return true;
+  }
+
+  bool PartialMerge(const Slice& /*key*/, const Slice& /*left_operand*/,
+                    const Slice& right_operand, std::string* new_value,
+                    Logger* /*logger*/) const override {
+    new_value->assign(right_operand.data(), right_operand.size());
+    return true;
+  }
+
+  using MergeOperator::PartialMergeMulti;
+  bool PartialMergeMulti(const Slice& /*key*/,
+                         const std::deque<Slice>& operand_list,
+                         std::string* new_value,
+                         Logger* /*logger*/) const override {
+    new_value->assign(operand_list.back().data(), operand_list.back().size());
+    return true;
+  }
+
+  static const char* kClassName() { return "PutOperator"; }
+  static const char* kNickName() { return "put_v1"; }
+  const char* Name() const override { return kClassName(); }
+  const char* NickName() const override { return kNickName(); }
+};
+
+class PutOperatorV2 : public PutOperator {
+  bool FullMerge(const Slice& /*key*/, const Slice* /*existing_value*/,
+                 const std::deque<std::string>& /*operand_sequence*/,
+                 std::string* /*new_value*/,
+                 Logger* /*logger*/) const override {
+    assert(false);
+    return false;
+  }
+
+  bool FullMergeV2(const MergeOperationInput& merge_in,
+                   MergeOperationOutput* merge_out) const override {
+    // Put basically only looks at the current/latest value
+    assert(!merge_in.operand_list.empty());
+    merge_out->existing_operand = merge_in.operand_list.back();
+    return true;
+  }
+
+  static const char* kNickName() { return "put"; }
+  const char* NickName() const override { return kNickName(); }
+};
+
+}  // end of anonymous namespace
+
+namespace ROCKSDB_NAMESPACE {
+
+std::shared_ptr<MergeOperator> MergeOperators::CreateDeprecatedPutOperator() {
+  return std::make_shared<PutOperator>();
+}
+
+std::shared_ptr<MergeOperator> MergeOperators::CreatePutOperator() {
+  return std::make_shared<PutOperatorV2>();
+}
+}  // namespace ROCKSDB_NAMESPACE
-- 
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