text: // Copyright (c) 2011 The LevelDB Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file. See the AUTHORS file for names of contributors.
  
  #ifndef STORAGE_LEVELDB_UTIL_MUTEXLOCK_H_
  #define STORAGE_LEVELDB_UTIL_MUTEXLOCK_H_
  
  #include "port/port.h"
  #include "port/thread_annotations.h"
  
  namespace leveldb {
  
  // Helper class that locks a mutex on construction and unlocks the mutex when
  // the destructor of the MutexLock object is invoked.
  //
  // Typical usage:
  //
  //   void MyClass::MyMethod() {
  //     MutexLock l(&mu_);       // mu_ is an instance variable
  //     ... some complex code, possibly with multiple return paths ...
  //   }
  
  class SCOPED_LOCKABLE MutexLock {
  public:
      explicit MutexLock(port::Mutex *mu) EXCLUSIVE_LOCK_FUNCTION(mu)
          : mu_(mu)  {
          this->mu_->Lock();
      }
      ~MutexLock() UNLOCK_FUNCTION() {
          this->mu_->Unlock();
      }
  
  private:
      port::Mutex *const mu_;
      // No copying allowed
      MutexLock(const MutexLock&);
      void operator=(const MutexLock&);
  };
  
  }  // namespace leveldb
  
  
  #endif  // STORAGE_LEVELDB_UTIL_MUTEXLOCK_H_
  