C++之MutexLock和MutexLockGuard封装

目录

• noncopyable.h
• mutexLockGuard.h
• test.cc

noncopyable.h

#ifndef NONCOPYABLE_H
#define NONCOPYABLE_H

namespace muduo
{

class noncopyable
{
 public:
  noncopyable(const noncopyable&) = delete;
  void operator=(const noncopyable&) = delete;

 protected:
  noncopyable() = default;
  ~noncopyable() = default;
};

}  // namespace muduo
 
#endif

mutexLockGuard.h

#ifndef MUTEXLOCKGUARD_H
#define MUTEXLOCKGUARD_H

#include "noncopyable.h"
#include <pthread.h>
namespace muduo {

class MutexLock : public muduo::noncopyable //表达语义
{
public:
  MutexLock() { pthread_mutex_init(&_mutex, NULL); }

  ~MutexLock() { pthread_mutex_destroy(&_mutex); }

  void lock() { pthread_mutex_lock(&_mutex); }

  void unlock() { pthread_mutex_unlock(&_mutex); }

  pthread_mutex_t *getMutexLockPtr() { return &_mutex; }

private:
  pthread_mutex_t _mutex;
};

// RAII
class MutexLockGuard {
public:
  MutexLockGuard(MutexLock &mutex) : mutexLock_(mutex) { mutexLock_.lock(); }

  ~MutexLockGuard() { mutexLock_.unlock(); }

private:
  MutexLock &mutexLock_;
};

} // namespace muduo

#endif

test.cc

#include "mutexLockGuard.h"
#include <iostream> // std::cout
#include <thread>   // std::thread
#include <vector>   // std::vector
using namespace muduo;

class Counter : muduo::noncopyable {
public:
  Counter() : value_(0) {}
  int value() const;
  int getAndIncrease();

private:
  int value_;
  mutable MutexLock mutex_;
};

int Counter::value() const {
  MutexLockGuard lock(mutex_);
  return value_;
}
int Counter::getAndIncrease() {
  MutexLockGuard lock(mutex_);
  int ret = value_++;
  return ret;
}

void increase_global(Counter &cnt, int n) {
  for (int i = 0; i < n; ++i)
    cnt.getAndIncrease();
}
int main() {
  Counter cnt;
  std::vector<std::thread> threads;

  std::cout << "increase global counter with 10 threads...
";
  for (int i = 1; i <= 10; ++i)
    threads.push_back(std::thread(increase_global, std::ref(cnt), 100));
  std::cout << "synchronizing all threads...
";
  for (auto &th : threads)
    th.join();

  std::cout << "global_counter: " << cnt.value() << '
';
  return 0;
}