/Users/deen/code/yugabyte-db/src/yb/rocksdb/table/internal_iterator.h
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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 | | #ifndef ROCKSDB_TABLE_INTERNAL_ITERATOR_H |
21 | | #define ROCKSDB_TABLE_INTERNAL_ITERATOR_H |
22 | | |
23 | | #pragma once |
24 | | |
25 | | #include <string> |
26 | | #include "yb/rocksdb/iterator.h" |
27 | | #include "yb/rocksdb/status.h" |
28 | | |
29 | | namespace rocksdb { |
30 | | |
31 | | class InternalIterator : public Cleanable { |
32 | | public: |
33 | 81.1M | InternalIterator() {} |
34 | 68.3M | virtual ~InternalIterator() {} |
35 | | |
36 | | // An iterator is either positioned at a key/value pair, or |
37 | | // not valid. This method returns true iff the iterator is valid. |
38 | | virtual bool Valid() const = 0; |
39 | | |
40 | | // Position at the first key in the source. The iterator is Valid() |
41 | | // after this call iff the source is not empty. |
42 | | virtual void SeekToFirst() = 0; |
43 | | |
44 | | // Position at the last key in the source. The iterator is |
45 | | // Valid() after this call iff the source is not empty. |
46 | | virtual void SeekToLast() = 0; |
47 | | |
48 | | // Position at the first key in the source that at or past target |
49 | | // The iterator is Valid() after this call iff the source contains |
50 | | // an entry that comes at or past target. |
51 | | // target is encoded representation of InternalKey. |
52 | | virtual void Seek(const Slice& target) = 0; |
53 | | |
54 | | // Moves to the next entry in the source. After this call, Valid() is |
55 | | // true iff the iterator was not positioned at the last entry in the source. |
56 | | // REQUIRES: Valid() |
57 | | virtual void Next() = 0; |
58 | | |
59 | | // Moves to the previous entry in the source. After this call, Valid() is |
60 | | // true iff the iterator was not positioned at the first entry in source. |
61 | | // REQUIRES: Valid() |
62 | | virtual void Prev() = 0; |
63 | | |
64 | | // Return the key for the current entry. The underlying storage for |
65 | | // the returned slice is valid only until the next modification of |
66 | | // the iterator. |
67 | | // REQUIRES: Valid() |
68 | | virtual Slice key() const = 0; |
69 | | |
70 | | // Return the value for the current entry. The underlying storage for |
71 | | // the returned slice is valid only until the next modification of |
72 | | // the iterator. |
73 | | // REQUIRES: !AtEnd() && !AtStart() |
74 | | virtual Slice value() const = 0; |
75 | | |
76 | | // If an error has occurred, return it. Else return an ok status. |
77 | | // If non-blocking IO is requested and this operation cannot be |
78 | | // satisfied without doing some IO, then this returns STATUS(Incomplete, ). |
79 | | virtual Status status() const = 0; |
80 | | |
81 | | // Make sure that all current and future data blocks used by this iterator |
82 | | // will be pinned in memory and will not be released except when |
83 | | // ReleasePinnedData() is called or the iterator is deleted. |
84 | 0 | virtual Status PinData() { return STATUS(NotSupported, ""); } Unexecuted instantiation: _ZN7rocksdb16InternalIterator7PinDataEv Unexecuted instantiation: _ZN7rocksdb16InternalIterator7PinDataEv |
85 | | |
86 | | // Release all blocks that were pinned because of PinData() and no future |
87 | | // blocks will be pinned. |
88 | 0 | virtual Status ReleasePinnedData() { return STATUS(NotSupported, ""); } Unexecuted instantiation: _ZN7rocksdb16InternalIterator17ReleasePinnedDataEv Unexecuted instantiation: _ZN7rocksdb16InternalIterator17ReleasePinnedDataEv |
89 | | |
90 | | // If true, this means that the Slice returned by key() is valid as long |
91 | | // as the iterator is not deleted and ReleasePinnedData() is not called. |
92 | | // |
93 | | // IsKeyPinned() is guaranteed to always return true if |
94 | | // - PinData() is called |
95 | | // - DB tables were created with BlockBasedTableOptions::use_delta_encoding |
96 | | // set to false. |
97 | 56.8k | virtual bool IsKeyPinned() const { return false; } |
98 | | |
99 | 4 | virtual Status GetProperty(std::string prop_name, std::string* prop) { |
100 | 4 | return STATUS(NotSupported, ""); |
101 | 4 | } |
102 | | |
103 | | private: |
104 | | // No copying allowed |
105 | | InternalIterator(const InternalIterator&) = delete; |
106 | | InternalIterator& operator=(const InternalIterator&) = delete; |
107 | | }; |
108 | | |
109 | | // Return an empty iterator (yields nothing). |
110 | | extern InternalIterator* NewEmptyInternalIterator(); |
111 | | |
112 | | // Return an empty iterator with the specified status. |
113 | | extern InternalIterator* NewErrorInternalIterator(const Status& status); |
114 | | |
115 | | } // namespace rocksdb |
116 | | |
117 | | #endif // ROCKSDB_TABLE_INTERNAL_ITERATOR_H |