/Users/deen/code/yugabyte-db/src/yb/rocksdb/table/filtering_iterator.h
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1 | | // Copyright (c) YugaByte, Inc. |
2 | | // |
3 | | // Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except |
4 | | // in compliance with the License. You may obtain a copy of the License at |
5 | | // |
6 | | // http://www.apache.org/licenses/LICENSE-2.0 |
7 | | // |
8 | | // Unless required by applicable law or agreed to in writing, software distributed under the License |
9 | | // is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express |
10 | | // or implied. See the License for the specific language governing permissions and limitations |
11 | | // under the License. |
12 | | // |
13 | | |
14 | | #ifndef YB_ROCKSDB_TABLE_FILTERING_ITERATOR_H |
15 | | #define YB_ROCKSDB_TABLE_FILTERING_ITERATOR_H |
16 | | |
17 | | #include "yb/rocksdb/table/internal_iterator.h" |
18 | | |
19 | | namespace rocksdb { |
20 | | |
21 | | class PossibleArenaDeleter { |
22 | | public: |
23 | 0 | explicit PossibleArenaDeleter(bool arena_mode) noexcept : arena_mode_(arena_mode) {} |
24 | | |
25 | | template <class P> |
26 | 0 | void operator()(P* p) { |
27 | 0 | if (arena_mode_) { |
28 | 0 | p->~P(); |
29 | 0 | } else { |
30 | 0 | delete p; |
31 | 0 | } |
32 | 0 | } |
33 | | private: |
34 | | bool arena_mode_; |
35 | | }; |
36 | | |
37 | | class FilteringIterator : public InternalIterator { |
38 | | public: |
39 | | explicit FilteringIterator(InternalIterator* iterator, bool arena_mode) |
40 | 0 | : iterator_(iterator, PossibleArenaDeleter(arena_mode)) {} |
41 | | |
42 | | private: |
43 | 0 | bool Valid() const override { |
44 | 0 | return iterator_->Valid(); |
45 | 0 | } |
46 | | |
47 | 0 | void SeekToFirst() override { |
48 | 0 | iterator_->SeekToFirst(); |
49 | 0 | ApplyFilter(/* backward = */ false); |
50 | 0 | } |
51 | | |
52 | 0 | void SeekToLast() override { |
53 | 0 | iterator_->SeekToLast(); |
54 | 0 | ApplyFilter(/* backward = */ true); |
55 | 0 | } |
56 | | |
57 | 0 | void Seek(const Slice& target) override { |
58 | 0 | iterator_->Seek(target); |
59 | 0 | ApplyFilter(/* backward = */ false); |
60 | 0 | } |
61 | | |
62 | 0 | void Next() override { |
63 | 0 | iterator_->Next(); |
64 | 0 | ApplyFilter(/* backward = */ false); |
65 | 0 | } |
66 | | |
67 | 0 | void Prev() override { |
68 | 0 | iterator_->Prev(); |
69 | 0 | ApplyFilter(/* backward = */ true); |
70 | 0 | } |
71 | | |
72 | 0 | Slice key() const override { |
73 | 0 | return iterator_->key(); |
74 | 0 | } |
75 | | |
76 | 0 | Slice value() const override { |
77 | 0 | return iterator_->value(); |
78 | 0 | } |
79 | | |
80 | 0 | Status status() const override { |
81 | 0 | return iterator_->status(); |
82 | 0 | } |
83 | | |
84 | 0 | Status PinData() override { |
85 | 0 | return iterator_->PinData(); |
86 | 0 | } |
87 | | |
88 | 0 | Status ReleasePinnedData() override { |
89 | 0 | return iterator_->ReleasePinnedData(); |
90 | 0 | } |
91 | | |
92 | 0 | bool IsKeyPinned() const override { |
93 | 0 | return iterator_->IsKeyPinned(); |
94 | 0 | } |
95 | | |
96 | 0 | Status GetProperty(std::string prop_name, std::string* prop) override { |
97 | 0 | return iterator_->GetProperty(std::move(prop_name), prop); |
98 | 0 | } |
99 | | |
100 | 0 | void ApplyFilter(bool backward) { |
101 | 0 | while (iterator_->Valid()) { |
102 | 0 | if (Satisfied(iterator_->key())) { |
103 | 0 | break; |
104 | 0 | } |
105 | 0 | if (!backward) { |
106 | 0 | iterator_->Next(); |
107 | 0 | } else { |
108 | 0 | iterator_->Prev(); |
109 | 0 | } |
110 | 0 | } |
111 | 0 | } |
112 | | |
113 | | virtual bool Satisfied(Slice key) = 0; |
114 | | |
115 | | const std::unique_ptr<InternalIterator, PossibleArenaDeleter> iterator_; |
116 | | }; |
117 | | |
118 | | } // namespace rocksdb |
119 | | |
120 | | #endif // YB_ROCKSDB_TABLE_FILTERING_ITERATOR_H |