//---------------------------------------------------------- -*- Mode: C++ -*-// $Id: concurrency.h 71 2008-07-07 15:49:14Z sriramsrao $ //// \brief Provide class definitions relating to concurrency.// // Created 2007/08/21// Author: Wang Lam (Kosmix Corp.) //// Copyright 2007 Kosmix Corp.//// This file is part of Kosmos File System (KFS).//// 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 LIBKFSCLIENT_CONCURRENCY_H#define LIBKFSCLIENT_CONCURRENCY_H#include <cerrno>#include <cassert>extern "C" {#include <pthread.h>}namespace KFS{    class MutexLock;}//// The MutexLock class is a convenience class that facilitates// locking a mutex on function entry and automatically unlocking// it on function exit.//class KFS::MutexLock {public:    /**     * Acquire the mutex     */    MutexLock( pthread_mutex_t *mutex ) : mMutex(mutex)     { pthread_mutex_lock(mMutex); }    /**     * Release the mutex automatically     */    ~MutexLock()    { int rval = pthread_mutex_unlock(mMutex); assert(!rval); (void)rval; }private:    pthread_mutex_t *mMutex;};#endif // LIBKFSCLIENT_CONCURRENCY_H