mirror of https://github.com/facebook/rocksdb.git
67 lines
1.8 KiB
C++
67 lines
1.8 KiB
C++
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same directory.
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//
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#pragma once
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#include <algorithm>
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#include <memory>
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#include <vector>
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#include "table/internal_iterator.h"
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namespace rocksdb {
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// PinnedIteratorsManager will be notified whenever we need to pin an Iterator
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// and it will be responsible for deleting pinned Iterators when they are
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// not needed anymore.
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class PinnedIteratorsManager {
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public:
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PinnedIteratorsManager() : pinning_enabled(false), pinned_iters_(nullptr) {}
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~PinnedIteratorsManager() { ReleasePinnedIterators(); }
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// Enable Iterators pinning
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void StartPinning() {
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if (!pinning_enabled) {
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pinning_enabled = true;
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if (!pinned_iters_) {
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pinned_iters_.reset(new std::vector<InternalIterator*>());
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}
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}
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}
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// Is pinning enabled ?
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bool PinningEnabled() { return pinning_enabled; }
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// Take ownership of iter if pinning is enabled and delete it when
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// ReleasePinnedIterators() is called
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void PinIteratorIfNeeded(InternalIterator* iter) {
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if (!pinning_enabled || !iter) {
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return;
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}
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pinned_iters_->push_back(iter);
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}
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// Release pinned Iterators
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inline void ReleasePinnedIterators() {
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if (pinning_enabled) {
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pinning_enabled = false;
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// Remove duplicate pointers
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std::sort(pinned_iters_->begin(), pinned_iters_->end());
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std::unique(pinned_iters_->begin(), pinned_iters_->end());
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for (auto& iter : *pinned_iters_) {
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delete iter;
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}
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pinned_iters_->clear();
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}
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}
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private:
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bool pinning_enabled;
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std::unique_ptr<std::vector<InternalIterator*>> pinned_iters_;
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};
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} // namespace rocksdb
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