https://github.com/facebook/rocksdb
Tip revision: a683d4aba9c1ba230248fc985b26208ee81bbc63 authored by Andrew Kryczka on 10 June 2016, 00:53:03 UTC
URI-based Env selection for db_bench
URI-based Env selection for db_bench
Tip revision: a683d4a
pinned_iterators_manager.h
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same directory.
//
#pragma once
#include <algorithm>
#include <memory>
#include <vector>
#include "table/internal_iterator.h"
namespace rocksdb {
// PinnedIteratorsManager will be notified whenever we need to pin an Iterator
// and it will be responsible for deleting pinned Iterators when they are
// not needed anymore.
class PinnedIteratorsManager {
public:
PinnedIteratorsManager() : pinning_enabled(false), pinned_iters_(nullptr) {}
~PinnedIteratorsManager() { assert(!pinning_enabled); }
// Enable Iterators pinning
void StartPinning() {
if (!pinning_enabled) {
pinning_enabled = true;
if (!pinned_iters_) {
pinned_iters_.reset(new std::vector<InternalIterator*>());
}
}
}
// Is pinning enabled ?
bool PinningEnabled() { return pinning_enabled; }
// Take ownership of iter if pinning is enabled and delete it when
// ReleasePinnedIterators() is called
void PinIteratorIfNeeded(InternalIterator* iter) {
if (!pinning_enabled || !iter) {
return;
}
pinned_iters_->push_back(iter);
}
// Release pinned Iterators
void ReleasePinnedIterators() {
if (pinning_enabled) {
pinning_enabled = false;
// Remove duplicate pointers
std::sort(pinned_iters_->begin(), pinned_iters_->end());
std::unique(pinned_iters_->begin(), pinned_iters_->end());
for (auto& iter : *pinned_iters_) {
delete iter;
}
pinned_iters_->clear();
}
}
private:
bool pinning_enabled;
std::unique_ptr<std::vector<InternalIterator*>> pinned_iters_;
};
} // namespace rocksdb