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// Copyright (c) Facebook, Inc. and its affiliates. 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 "rocksdb/rocksdb_namespace.h"
// This file declares a wrapper around the efficient folly DistributedMutex
// that falls back on a standard mutex when not available. See
// https://github.com/facebook/folly/blob/main/folly/synchronization/DistributedMutex.h
// for benefits and limitations.
// At the moment, only scoped locking is supported using DMutexLock
// RAII wrapper, because lock/unlock APIs will vary.
#ifdef USE_FOLLY
#include <folly/synchronization/DistributedMutex.h>
namespace ROCKSDB_NAMESPACE {
class DMutex : public folly::DistributedMutex {
public:
static const char* kName() { return "folly::DistributedMutex"; }
explicit DMutex(bool IGNORED_adaptive = false) { (void)IGNORED_adaptive; }
// currently no-op
void AssertHeld() const {}
};
using DMutexLock = std::lock_guard<folly::DistributedMutex>;
} // namespace ROCKSDB_NAMESPACE
#else
#include <mutex>
#include "port/port.h"
namespace ROCKSDB_NAMESPACE {
using DMutex = port::Mutex;
using DMutexLock = std::lock_guard<DMutex>;
} // namespace ROCKSDB_NAMESPACE
#endif
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