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7c673cae | 1 | // Copyright (c) 2011-present, Facebook, Inc. All rights reserved. |
11fdf7f2 TL |
2 | // This source code is licensed under both the GPLv2 (found in the |
3 | // COPYING file in the root directory) and Apache 2.0 License | |
4 | // (found in the LICENSE.Apache file in the root directory). | |
7c673cae FG |
5 | // |
6 | #pragma once | |
7 | #include <algorithm> | |
8 | #include <memory> | |
9 | #include <utility> | |
10 | #include <vector> | |
11 | ||
12 | #include "table/internal_iterator.h" | |
13 | ||
f67539c2 | 14 | namespace ROCKSDB_NAMESPACE { |
7c673cae FG |
15 | |
16 | // PinnedIteratorsManager will be notified whenever we need to pin an Iterator | |
17 | // and it will be responsible for deleting pinned Iterators when they are | |
18 | // not needed anymore. | |
19 | class PinnedIteratorsManager : public Cleanable { | |
20 | public: | |
21 | PinnedIteratorsManager() : pinning_enabled(false) {} | |
22 | ~PinnedIteratorsManager() { | |
23 | if (pinning_enabled) { | |
24 | ReleasePinnedData(); | |
25 | } | |
26 | } | |
27 | ||
1e59de90 TL |
28 | // Move constructor and move assignment is allowed. |
29 | PinnedIteratorsManager(PinnedIteratorsManager&& other) noexcept = default; | |
30 | PinnedIteratorsManager& operator=(PinnedIteratorsManager&& other) noexcept = | |
31 | default; | |
32 | ||
7c673cae FG |
33 | // Enable Iterators pinning |
34 | void StartPinning() { | |
35 | assert(pinning_enabled == false); | |
36 | pinning_enabled = true; | |
37 | } | |
38 | ||
39 | // Is pinning enabled ? | |
40 | bool PinningEnabled() { return pinning_enabled; } | |
41 | ||
42 | // Take ownership of iter and delete it when ReleasePinnedData() is called | |
43 | void PinIterator(InternalIterator* iter, bool arena = false) { | |
44 | if (arena) { | |
45 | PinPtr(iter, &PinnedIteratorsManager::ReleaseArenaInternalIterator); | |
46 | } else { | |
47 | PinPtr(iter, &PinnedIteratorsManager::ReleaseInternalIterator); | |
48 | } | |
49 | } | |
50 | ||
1e59de90 | 51 | using ReleaseFunction = void (*)(void* arg1); |
7c673cae FG |
52 | void PinPtr(void* ptr, ReleaseFunction release_func) { |
53 | assert(pinning_enabled); | |
54 | if (ptr == nullptr) { | |
55 | return; | |
56 | } | |
57 | pinned_ptrs_.emplace_back(ptr, release_func); | |
58 | } | |
59 | ||
60 | // Release pinned Iterators | |
61 | inline void ReleasePinnedData() { | |
62 | assert(pinning_enabled == true); | |
63 | pinning_enabled = false; | |
64 | ||
65 | // Remove duplicate pointers | |
66 | std::sort(pinned_ptrs_.begin(), pinned_ptrs_.end()); | |
67 | auto unique_end = std::unique(pinned_ptrs_.begin(), pinned_ptrs_.end()); | |
68 | ||
69 | for (auto i = pinned_ptrs_.begin(); i != unique_end; ++i) { | |
70 | void* ptr = i->first; | |
71 | ReleaseFunction release_func = i->second; | |
72 | release_func(ptr); | |
73 | } | |
74 | pinned_ptrs_.clear(); | |
75 | // Also do cleanups from the base Cleanable | |
76 | Cleanable::Reset(); | |
77 | } | |
78 | ||
79 | private: | |
80 | static void ReleaseInternalIterator(void* ptr) { | |
81 | delete reinterpret_cast<InternalIterator*>(ptr); | |
82 | } | |
83 | ||
84 | static void ReleaseArenaInternalIterator(void* ptr) { | |
85 | reinterpret_cast<InternalIterator*>(ptr)->~InternalIterator(); | |
86 | } | |
87 | ||
88 | bool pinning_enabled; | |
89 | std::vector<std::pair<void*, ReleaseFunction>> pinned_ptrs_; | |
90 | }; | |
91 | ||
f67539c2 | 92 | } // namespace ROCKSDB_NAMESPACE |