text: // Licensed to the Apache Software Foundation (ASF) under one
  // or more contributor license agreements.  See the NOTICE file
  // distributed with this work for additional information
  // regarding copyright ownership.  The ASF licenses this file
  // to you 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.
  //
  // 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.
  //
  #ifndef YB_BOOST_MUTEX_UTILS_H
  #define YB_BOOST_MUTEX_UTILS_H
  
  
  // Similar to std::lock_guard except that it takes
  // a lock pointer, and checks against nullptr. 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 != nullptr) {
        l->lock();
      }
    }
  
    ~lock_guard_maybe() {
      if (lock_ != nullptr) {
        lock_->unlock();
      }
    }
  
   private:
    LockType *lock_;
  };
  
  #endif
  