5e94f68f35
Summary: Prototype of API to allow MyRocks to override default Mutex/CondVar used by transactions with their own implementations. They would simply need to pass their own implementations of Mutex/CondVar to the templated TransactionDB::Open(). Default implementation of TransactionDBMutex/TransactionDBCondVar provided (but the code is not currently changed to use this). Let me know if this API makes sense or if it should be changed Test Plan: n/a Reviewers: yhchiang, rven, igor, sdong, spetrunia Reviewed By: spetrunia Subscribers: maykov, dhruba, leveldb Differential Revision: https://reviews.facebook.net/D43761
93 lines
3.2 KiB
C++
93 lines
3.2 KiB
C++
// Copyright (c) 2015, 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
|
|
#ifndef ROCKSDB_LITE
|
|
|
|
#include <memory>
|
|
|
|
#include "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 should 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
|