Lock& lock_;
};
+class Hold_optional_lock
+{
+ public:
+ Hold_optional_lock(Lock* lock)
+ : lock_(lock)
+ {
+ if (this->lock_ != NULL)
+ this->lock_->acquire();
+ }
+
+ ~Hold_optional_lock()
+ {
+ if (this->lock_ != NULL)
+ this->lock_->release();
+ }
+
+ private:
+ Hold_optional_lock(const Hold_optional_lock&);
+ Hold_optional_lock& operator=(const Hold_optional_lock&);
+
+ Lock* lock_;
+};
+
// The interface for the implementation of a condition variable.
class Condvar_impl