1 files changed, 135 insertions, 0 deletions
diff --git a/src/rocksdb/utilities/transactions/transaction_db_mutex_impl.cc b/src/rocksdb/utilities/transactions/transaction_db_mutex_impl.cc
new file mode 100644
index 00000000..244a9507
--- /dev/null
+++ b/src/rocksdb/utilities/transactions/transaction_db_mutex_impl.cc
@@ -0,0 +1,135 @@
+//  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).
+
+#ifndef ROCKSDB_LITE
+
+#include "utilities/transactions/transaction_db_mutex_impl.h"
+
+#include <chrono>
+#include <condition_variable>
+#include <functional>
+#include <mutex>
+
+#include "rocksdb/utilities/transaction_db_mutex.h"
+
+namespace rocksdb {
+
+class TransactionDBMutexImpl : public TransactionDBMutex {
+ public:
+  TransactionDBMutexImpl() {}
+  ~TransactionDBMutexImpl() override {}
+
+  Status Lock() override;
+
+  Status TryLockFor(int64_t timeout_time) override;
+
+  void UnLock() override { mutex_.unlock(); }
+
+  friend class TransactionDBCondVarImpl;
+
+ private:
+  std::mutex mutex_;
+};
+
+class TransactionDBCondVarImpl : public TransactionDBCondVar {
+ public:
+  TransactionDBCondVarImpl() {}
+  ~TransactionDBCondVarImpl() override {}
+
+  Status Wait(std::shared_ptr<TransactionDBMutex> mutex) override;
+
+  Status WaitFor(std::shared_ptr<TransactionDBMutex> mutex,
+                 int64_t timeout_time) override;
+
+  void Notify() override { cv_.notify_one(); }
+
+  void NotifyAll() override { cv_.notify_all(); }
+
+ private:
+  std::condition_variable cv_;
+};
+
+std::shared_ptr<TransactionDBMutex>
+TransactionDBMutexFactoryImpl::AllocateMutex() {
+  return std::shared_ptr<TransactionDBMutex>(new TransactionDBMutexImpl());
+}
+
+std::shared_ptr<TransactionDBCondVar>
+TransactionDBMutexFactoryImpl::AllocateCondVar() {
+  return std::shared_ptr<TransactionDBCondVar>(new TransactionDBCondVarImpl());
+}
+
+Status TransactionDBMutexImpl::Lock() {
+  mutex_.lock();
+  return Status::OK();
+}
+
+Status TransactionDBMutexImpl::TryLockFor(int64_t timeout_time) {
+  bool locked = true;
+
+  if (timeout_time == 0) {
+    locked = mutex_.try_lock();
+  } else {
+    // Previously, this code used a std::timed_mutex.  However, this was changed
+    // due to known bugs in gcc versions < 4.9.
+    // https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54562
+    //
+    // Since this mutex isn't held for long and only a single mutex is ever
+    // held at a time, it is reasonable to ignore the lock timeout_time here
+    // and only check it when waiting on the condition_variable.
+    mutex_.lock();
+  }
+
+  if (!locked) {
+    // timeout acquiring mutex
+    return Status::TimedOut(Status::SubCode::kMutexTimeout);
+  }
+
+  return Status::OK();
+}
+
+Status TransactionDBCondVarImpl::Wait(
+    std::shared_ptr<TransactionDBMutex> mutex) {
+  auto mutex_impl = reinterpret_cast<TransactionDBMutexImpl*>(mutex.get());
+
+  std::unique_lock<std::mutex> lock(mutex_impl->mutex_, std::adopt_lock);
+  cv_.wait(lock);
+
+  // Make sure unique_lock doesn't unlock mutex when it destructs
+  lock.release();
+
+  return Status::OK();
+}
+
+Status TransactionDBCondVarImpl::WaitFor(
+    std::shared_ptr<TransactionDBMutex> mutex, int64_t timeout_time) {
+  Status s;
+
+  auto mutex_impl = reinterpret_cast<TransactionDBMutexImpl*>(mutex.get());
+  std::unique_lock<std::mutex> lock(mutex_impl->mutex_, std::adopt_lock);
+
+  if (timeout_time < 0) {
+    // If timeout is negative, do not use a timeout
+    cv_.wait(lock);
+  } else {
+    auto duration = std::chrono::microseconds(timeout_time);
+    auto cv_status = cv_.wait_for(lock, duration);
+
+    // Check if the wait stopped due to timing out.
+    if (cv_status == std::cv_status::timeout) {
+      s = Status::TimedOut(Status::SubCode::kMutexTimeout);
+    }
+  }
+
+  // Make sure unique_lock doesn't unlock mutex when it destructs
+  lock.release();
+
+  // CV was signaled, or we spuriously woke up (but didn't time out)
+  return s;
+}
+
+}  // namespace rocksdb
+
+#endif  // ROCKSDB_LITE