1 files changed, 91 insertions, 0 deletions
diff --git a/src/rocksdb/include/rocksdb/utilities/transaction_db_mutex.h b/src/rocksdb/include/rocksdb/utilities/transaction_db_mutex.h
new file mode 100644
index 000000000..e352f325a
--- /dev/null
+++ b/src/rocksdb/include/rocksdb/utilities/transaction_db_mutex.h
@@ -0,0 +1,91 @@
+//  Copyright (c) 2011-present, 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
+#ifndef ROCKSDB_LITE
+
+#include <memory>
+
+#include "rocksdb/status.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+// 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 otherwise 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_NAMESPACE
+
+#endif  // ROCKSDB_LITE