/Users/deen/code/yugabyte-db/src/yb/rocksdb/utilities/merge_operators/uint64add.cc
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1 | | // Copyright (c) 2011-present, Facebook, Inc. All rights reserved. |
2 | | // This source code is licensed under the BSD-style license found in the |
3 | | // LICENSE file in the root directory of this source tree. An additional grant |
4 | | // of patent rights can be found in the PATENTS file in the same directory. |
5 | | // |
6 | | // The following only applies to changes made to this file as part of YugaByte development. |
7 | | // |
8 | | // Portions Copyright (c) YugaByte, Inc. |
9 | | // |
10 | | // Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except |
11 | | // in compliance with the License. You may obtain a copy of the License at |
12 | | // |
13 | | // http://www.apache.org/licenses/LICENSE-2.0 |
14 | | // |
15 | | // Unless required by applicable law or agreed to in writing, software distributed under the License |
16 | | // is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express |
17 | | // or implied. See the License for the specific language governing permissions and limitations |
18 | | // under the License. |
19 | | // |
20 | | |
21 | | #include <memory> |
22 | | |
23 | | #include "yb/rocksdb/env.h" |
24 | | #include "yb/rocksdb/merge_operator.h" |
25 | | #include "yb/util/slice.h" |
26 | | #include "yb/rocksdb/util/coding.h" |
27 | | #include "yb/rocksdb/utilities/merge_operators.h" |
28 | | |
29 | | using namespace rocksdb; |
30 | | |
31 | | namespace { // anonymous namespace |
32 | | |
33 | | // A 'model' merge operator with uint64 addition semantics |
34 | | // Implemented as an AssociativeMergeOperator for simplicity and example. |
35 | | class UInt64AddOperator : public AssociativeMergeOperator { |
36 | | public: |
37 | | virtual bool Merge(const Slice& key, |
38 | | const Slice* existing_value, |
39 | | const Slice& value, |
40 | | std::string* new_value, |
41 | 2.33k | Logger* logger) const override { |
42 | 2.33k | uint64_t orig_value = 0; |
43 | 2.33k | if (existing_value){ |
44 | 1.13k | orig_value = DecodeInteger(*existing_value, logger); |
45 | 1.13k | } |
46 | 2.33k | uint64_t operand = DecodeInteger(value, logger); |
47 | | |
48 | 2.33k | assert(new_value); |
49 | 2.33k | new_value->clear(); |
50 | 2.33k | PutFixed64(new_value, orig_value + operand); |
51 | | |
52 | 2.33k | return true; // Return true always since corruption will be treated as 0 |
53 | 2.33k | } |
54 | | |
55 | 524 | const char* Name() const override { |
56 | 524 | return "UInt64AddOperator"; |
57 | 524 | } |
58 | | |
59 | | private: |
60 | | // Takes the string and decodes it into a uint64_t |
61 | | // On error, prints a message and returns 0 |
62 | 3.46k | uint64_t DecodeInteger(const Slice& value, Logger* logger) const { |
63 | 3.46k | uint64_t result = 0; |
64 | | |
65 | 3.46k | if (value.size() == sizeof(uint64_t)) { |
66 | 3.46k | result = DecodeFixed64(value.data()); |
67 | 0 | } else if (logger != nullptr) { |
68 | | // If value is corrupted, treat it as 0 |
69 | 0 | RLOG(InfoLogLevel::ERROR_LEVEL, logger, |
70 | 0 | "uint64 value corruption, size: %" ROCKSDB_PRIszt |
71 | 0 | " > %" ROCKSDB_PRIszt, |
72 | 0 | value.size(), sizeof(uint64_t)); |
73 | 0 | } |
74 | | |
75 | 3.46k | return result; |
76 | 3.46k | } |
77 | | |
78 | | }; |
79 | | |
80 | | } |
81 | | |
82 | | namespace rocksdb { |
83 | | |
84 | 41 | std::shared_ptr<MergeOperator> MergeOperators::CreateUInt64AddOperator() { |
85 | 41 | return std::make_shared<UInt64AddOperator>(); |
86 | 41 | } |
87 | | |
88 | | } |