68 lines
1.4 KiB
C
68 lines
1.4 KiB
C
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// Copyright (c) 2013, 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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#pragma once
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#include <limits>
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#include <list>
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#include "util/mutexlock.h"
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namespace rocksdb {
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//
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// Simple synchronized queue implementation with the option of
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// bounding the queue
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//
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// On overflow, the elements will be discarded
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//
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template <class T>
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class BoundedQueue {
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public:
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explicit BoundedQueue(
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const size_t max_size = std::numeric_limits<size_t>::max())
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: cond_empty_(&lock_), max_size_(max_size) {}
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virtual ~BoundedQueue() {}
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void Push(T&& t) {
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MutexLock _(&lock_);
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if (max_size_ != std::numeric_limits<size_t>::max() &&
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size_ + t.Size() >= max_size_) {
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// overflow
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return;
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}
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size_ += t.Size();
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q_.push_back(std::move(t));
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cond_empty_.SignalAll();
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}
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T Pop() {
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MutexLock _(&lock_);
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while (q_.empty()) {
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cond_empty_.Wait();
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}
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T t = std::move(q_.front());
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size_ -= t.Size();
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q_.pop_front();
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return std::move(t);
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}
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size_t Size() const {
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MutexLock _(&lock_);
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return size_;
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}
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private:
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mutable port::Mutex lock_;
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port::CondVar cond_empty_;
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std::list<T> q_;
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size_t size_ = 0;
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const size_t max_size_;
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};
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} // namespace rocksdb
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