src/kudu/util/boost_mutex_utils.h

// Copyright 2012 Cloudera, 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.
#ifndef KUDU_BOOST_MUTEX_UTILS_H
#define KUDU_BOOST_MUTEX_UTILS_H


// Similar to boost::lock_guard except that it takes
// a lock pointer, and checks against NULL. If the
// pointer is NULL, does nothing. Otherwise guards
// with the lock.
template<class LockType>
class lock_guard_maybe {
 public:
  explicit lock_guard_maybe(LockType *l) :
    lock_(l) {
    if (l != NULL) {
      l->lock();
    }
  }

  ~lock_guard_maybe() {
    if (lock_ != NULL) {
      lock_->unlock();
    }
  }

 private:
  LockType *lock_;
};

#endif