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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 | ||
14 | namespace rocksdb { | |
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 | ||
28 | // Enable Iterators pinning | |
29 | void StartPinning() { | |
30 | assert(pinning_enabled == false); | |
31 | pinning_enabled = true; | |
32 | } | |
33 | ||
34 | // Is pinning enabled ? | |
35 | bool PinningEnabled() { return pinning_enabled; } | |
36 | ||
37 | // Take ownership of iter and delete it when ReleasePinnedData() is called | |
38 | void PinIterator(InternalIterator* iter, bool arena = false) { | |
39 | if (arena) { | |
40 | PinPtr(iter, &PinnedIteratorsManager::ReleaseArenaInternalIterator); | |
41 | } else { | |
42 | PinPtr(iter, &PinnedIteratorsManager::ReleaseInternalIterator); | |
43 | } | |
44 | } | |
45 | ||
46 | typedef void (*ReleaseFunction)(void* arg1); | |
47 | void PinPtr(void* ptr, ReleaseFunction release_func) { | |
48 | assert(pinning_enabled); | |
49 | if (ptr == nullptr) { | |
50 | return; | |
51 | } | |
52 | pinned_ptrs_.emplace_back(ptr, release_func); | |
53 | } | |
54 | ||
55 | // Release pinned Iterators | |
56 | inline void ReleasePinnedData() { | |
57 | assert(pinning_enabled == true); | |
58 | pinning_enabled = false; | |
59 | ||
60 | // Remove duplicate pointers | |
61 | std::sort(pinned_ptrs_.begin(), pinned_ptrs_.end()); | |
62 | auto unique_end = std::unique(pinned_ptrs_.begin(), pinned_ptrs_.end()); | |
63 | ||
64 | for (auto i = pinned_ptrs_.begin(); i != unique_end; ++i) { | |
65 | void* ptr = i->first; | |
66 | ReleaseFunction release_func = i->second; | |
67 | release_func(ptr); | |
68 | } | |
69 | pinned_ptrs_.clear(); | |
70 | // Also do cleanups from the base Cleanable | |
71 | Cleanable::Reset(); | |
72 | } | |
73 | ||
74 | private: | |
75 | static void ReleaseInternalIterator(void* ptr) { | |
76 | delete reinterpret_cast<InternalIterator*>(ptr); | |
77 | } | |
78 | ||
79 | static void ReleaseArenaInternalIterator(void* ptr) { | |
80 | reinterpret_cast<InternalIterator*>(ptr)->~InternalIterator(); | |
81 | } | |
82 | ||
83 | bool pinning_enabled; | |
84 | std::vector<std::pair<void*, ReleaseFunction>> pinned_ptrs_; | |
85 | }; | |
86 | ||
87 | } // namespace rocksdb |