mutexlock.h raw

   1  // Copyright (c) 2011 The LevelDB Authors. All rights reserved.
   2  // Use of this source code is governed by a BSD-style license that can be
   3  // found in the LICENSE file. See the AUTHORS file for names of contributors.
   4  
   5  #ifndef STORAGE_LEVELDB_UTIL_MUTEXLOCK_H_
   6  #define STORAGE_LEVELDB_UTIL_MUTEXLOCK_H_
   7  
   8  #include "port/port.h"
   9  #include "port/thread_annotations.h"
  10  
  11  namespace leveldb {
  12  
  13  // Helper class that locks a mutex on construction and unlocks the mutex when
  14  // the destructor of the MutexLock object is invoked.
  15  //
  16  // Typical usage:
  17  //
  18  //   void MyClass::MyMethod() {
  19  //     MutexLock l(&mu_);       // mu_ is an instance variable
  20  //     ... some complex code, possibly with multiple return paths ...
  21  //   }
  22  
  23  class SCOPED_LOCKABLE MutexLock {
  24   public:
  25    explicit MutexLock(port::Mutex* mu) EXCLUSIVE_LOCK_FUNCTION(mu) : mu_(mu) {
  26      this->mu_->Lock();
  27    }
  28    ~MutexLock() UNLOCK_FUNCTION() { this->mu_->Unlock(); }
  29  
  30    MutexLock(const MutexLock&) = delete;
  31    MutexLock& operator=(const MutexLock&) = delete;
  32  
  33   private:
  34    port::Mutex* const mu_;
  35  };
  36  
  37  }  // namespace leveldb
  38  
  39  #endif  // STORAGE_LEVELDB_UTIL_MUTEXLOCK_H_
  40