1 | // Copyright (c) 2011 The LevelDB Authors. All rights reserved. |
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2 | // Use of this source code is governed by a BSD-style license that can be |
3 | // found in the LICENSE file. See the AUTHORS file for names of contributors. |
4 | |
5 | #include "leveldb/iterator.h" |
6 | |
7 | namespace leveldb { |
8 | |
9 | Iterator::Iterator() { |
10 | cleanup_head_.function = nullptr; |
11 | cleanup_head_.next = nullptr; |
12 | } |
13 | |
14 | Iterator::~Iterator() { |
15 | if (!cleanup_head_.IsEmpty()) { |
16 | cleanup_head_.Run(); |
17 | for (CleanupNode* node = cleanup_head_.next; node != nullptr;) { |
18 | node->Run(); |
19 | CleanupNode* next_node = node->next; |
20 | delete node; |
21 | node = next_node; |
22 | } |
23 | } |
24 | } |
25 | |
26 | void Iterator::RegisterCleanup(CleanupFunction func, void* arg1, void* arg2) { |
27 | assert(func != nullptr); |
28 | CleanupNode* node; |
29 | if (cleanup_head_.IsEmpty()) { |
30 | node = &cleanup_head_; |
31 | } else { |
32 | node = new CleanupNode(); |
33 | node->next = cleanup_head_.next; |
34 | cleanup_head_.next = node; |
35 | } |
36 | node->function = func; |
37 | node->arg1 = arg1; |
38 | node->arg2 = arg2; |
39 | } |
40 | |
41 | namespace { |
42 | |
43 | class EmptyIterator : public Iterator { |
44 | public: |
45 | EmptyIterator(const Status& s) : status_(s) {} |
46 | ~EmptyIterator() override = default; |
47 | |
48 | bool Valid() const override { return false; } |
49 | void Seek(const Slice& target) override {} |
50 | void SeekToFirst() override {} |
51 | void SeekToLast() override {} |
52 | void Next() override { assert(false); } |
53 | void Prev() override { assert(false); } |
54 | Slice key() const override { |
55 | assert(false); |
56 | return Slice(); |
57 | } |
58 | Slice value() const override { |
59 | assert(false); |
60 | return Slice(); |
61 | } |
62 | Status status() const override { return status_; } |
63 | |
64 | private: |
65 | Status status_; |
66 | }; |
67 | |
68 | } // anonymous namespace |
69 | |
70 | Iterator* NewEmptyIterator() { return new EmptyIterator(Status::OK()); } |
71 | |
72 | Iterator* NewErrorIterator(const Status& status) { |
73 | return new EmptyIterator(status); |
74 | } |
75 | |
76 | } // namespace leveldb |
77 |