YugabyteDB (2.13.1.0-b60, 21121d69985fbf76aa6958d8f04a9bfa936293b5)

//  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.

//

// The following only applies to changes made to this file as part of YugaByte development.

//

// Portions Copyright (c) YugaByte, Inc.

//

// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except

// in compliance with the License.  You may obtain a copy of the License at

//

// http://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing, software distributed under the License

// is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express

// or implied.  See the License for the specific language governing permissions and limitations

// under the License.

//

#pragma once

#ifndef ROCKSDB_LITE

#include <memory>

#include "yb/rocksdb/status.h"

namespace rocksdb {

// TransactionDBMutex and TransactionDBCondVar APIs allows applications to

// implement custom mutexes and condition variables to be used by a

// TransactionDB when locking keys.

//

// To open a TransactionDB with a custom TransactionDBMutexFactory, set

// TransactionDBOptions.custom_mutex_factory.

class TransactionDBMutex {

 public:

  virtual ~TransactionDBMutex() {}

  // Attempt to acquire lock.  Return OK on success, or other Status on failure.

  // If returned status is OK, TransactionDB will eventually call UnLock().

  virtual Status Lock() = 0;

  // Attempt to acquire lock.  If timeout is non-negative, operation may be

  // failed after this many microseconds.

  // Returns OK on success,

  //         TimedOut if timed out,

  //         or other Status on failure.

  // If returned status is OK, TransactionDB will eventually call UnLock().

  virtual Status TryLockFor(int64_t timeout_time) = 0;

  // Unlock Mutex that was successfully locked by Lock() or TryLockUntil()

  virtual void UnLock() = 0;

};

class TransactionDBCondVar {

 public:

  virtual ~TransactionDBCondVar() {}

  // Block current thread until condition variable is notified by a call to

  // Notify() or NotifyAll().  Wait() will be called with mutex locked.

  // Returns OK if notified.

  // Returns non-OK if TransactionDB should stop waiting and fail the operation.

  // May return OK spuriously even if not notified.

  virtual Status Wait(std::shared_ptr<TransactionDBMutex> mutex) = 0;

  // Block current thread until condition variable is notified by a call to

  // Notify() or NotifyAll(), or if the timeout is reached.

  // Wait() will be called with mutex locked.

  //

  // If timeout is non-negative, operation should be failed after this many

  // microseconds.

  // If implementing a custom version of this class, the implementation may

  // choose to ignore the timeout.

  //

  // Returns OK if notified.

  // Returns TimedOut if timeout is reached.

  // Returns other status if TransactionDB should otherwis stop waiting and

  //  fail the operation.

  // May return OK spuriously even if not notified.

  virtual Status WaitFor(std::shared_ptr<TransactionDBMutex> mutex,

                         int64_t timeout_time) = 0;

  // If any threads are waiting on *this, unblock at least one of the

  // waiting threads.

  virtual void Notify() = 0;

  // Unblocks all threads waiting on *this.

  virtual void NotifyAll() = 0;

};

// Factory class that can allocate mutexes and condition variables.

class TransactionDBMutexFactory {

 public:

  // Create a TransactionDBMutex object.

  virtual std::shared_ptr<TransactionDBMutex> AllocateMutex() = 0;

  // Create a TransactionDBCondVar object.

  virtual std::shared_ptr<TransactionDBCondVar> AllocateCondVar() = 0;

  virtual ~TransactionDBMutexFactory() {}

};

}  // namespace rocksdb

#endif  // ROCKSDB_LITE