rocksdb/utilities/persistent_cache/persistent_cache_util.h
Siying Dong 6189230202 Change RocksDB License
Summary: Closes https://github.com/facebook/rocksdb/pull/2589

Differential Revision: D5431502

Pulled By: siying

fbshipit-source-id: 8ebf8c87883daa9daa54b2303d11ce01ab1f6f75
2017-07-20 17:20:44 -07:00

68 lines
1.4 KiB
C++

// Copyright (c) 2013, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
#pragma once
#include <limits>
#include <list>
#include "util/mutexlock.h"
namespace rocksdb {
//
// Simple synchronized queue implementation with the option of
// bounding the queue
//
// On overflow, the elements will be discarded
//
template <class T>
class BoundedQueue {
public:
explicit BoundedQueue(
const size_t max_size = std::numeric_limits<size_t>::max())
: cond_empty_(&lock_), max_size_(max_size) {}
virtual ~BoundedQueue() {}
void Push(T&& t) {
MutexLock _(&lock_);
if (max_size_ != std::numeric_limits<size_t>::max() &&
size_ + t.Size() >= max_size_) {
// overflow
return;
}
size_ += t.Size();
q_.push_back(std::move(t));
cond_empty_.SignalAll();
}
T Pop() {
MutexLock _(&lock_);
while (q_.empty()) {
cond_empty_.Wait();
}
T t = std::move(q_.front());
size_ -= t.Size();
q_.pop_front();
return std::move(t);
}
size_t Size() const {
MutexLock _(&lock_);
return size_;
}
private:
mutable port::Mutex lock_;
port::CondVar cond_empty_;
std::list<T> q_;
size_t size_ = 0;
const size_t max_size_;
};
} // namespace rocksdb