[多线程] 生产者消费者模型的BOOST实现

说明

如果 使用过程中有BUG 一定要告诉我：在下面留言或者给我邮件（sawpara at 126 dot com）

使用boost::thread库来实现生产者消费者模型中的缓冲区！

• 仓库内最多可以存放 capacity 个产品。
• 条件变量 condition_put 标记是否可以往仓库中存放一个产品。
• 条件变量 condition_get 标记是否可以从仓库中取出一个产品。
• 互斥量 mutexer 用于保证当前仓库只有一个线程拥有主权。

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实现

#include <queue>#include "boost/thread/condition.hpp"#include "boost/thread/mutex.hpp"template<class Product>class Repository{public:  Repository() : _capacity(2), _emptynum(_capacity){}  Repository(int capacity) : _emptynum(capacity), _capacity(capacity){}  // success : when new_capacity > _capacity - _emptynum  bool set_capacity(int new_capacity){    boost::mutex::scoped_lock lock();    if (_capacity - _emptynum < new_capacity ){            _emptynum = new_capacity - _capacity + _emptynum;      _capacity = new_capacity;      return true;    }    return false;  }  bool empty(){    boost::mutex::scoped_lock lock(_mutexer);    return _is_empty();  }  void put(Product &product){    {      boost::mutex::scoped_lock lock(_mutexer);      while (_is_full()){        // unlock _mutexer and blocked until _condition_put.notifiy_one/all is called.        _condition_put.wait(_mutexer);       }      _products.push(product); // need implement the copy constructor and =       _emptynum--; // decrease empty position    }    _condition_get.notify_one(); // have put one, one another thread can get product now  }  void get(Product &product){    {      // lock this repository      boost::mutex::scoped_lock lock(_mutexer);      while (_is_empty()){        // unlock _mutexer and blocked until _condition_put.notifiy_one/all is called.        _condition_get.wait(_mutexer);      }      product = _products.front(); // need implement the copy constructor and =       _products.pop();      _emptynum++; // increase empty position    }    // have removed one product, one another thread can put product now    _condition_put.notify_one();   }private:  inline bool _is_full (){ return _emptynum ==         0; } // if have empty position  inline bool _is_empty(){ return _emptynum == _capacity; } // private:  int _capacity; // capacity of this repository  int _emptynum; // number of empty position  std::queue<Product> _products; // products in a FIFO queue  boost::mutex _mutexer; // race access  boost::condition _condition_put;   boost::condition _condition_get;};

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实验

#include <iostream>#include "boost/thread.hpp"boost::mutex g_io_mutexer;boost::mutex g_mutexer;bool g_is_finished = false;Repository<int> g_repository(4);void producing(){  for (int i = 0; i < 100; i++){    {      boost::mutex::scoped_lock lock(g_io_mutexer);      std::cout << "Producing product : " << i << std::endl;    }    g_repository.put(i);  }  boost::mutex::scoped_lock lock(g_mutexer);  g_is_finished = true;}void consuming(){  int product;  while (true){    {      boost::mutex::scoped_lock lock(g_mutexer);      if (g_is_finished && g_repository.empty()){        break;      }    }    g_repository.get(product);    {      boost::mutex::scoped_lock lock(g_io_mutexer);      std::cout << "Consuming product : " << product << std::endl;    }  }}int main(){  boost::thread producer(producing);  boost::thread consumer_1(consuming);  boost::thread consumer_2(consuming);  producer.join();  consumer_1.join();  consumer_2.join();  return 0;}

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all the code

为方便理解代码，下面的代码中，三个空行一个意群。

#include <iostream>#include <queue>#include "boost/thread.hpp"#include "boost/thread/condition.hpp"#include "boost/thread/mutex.hpp"template<class Product>class Repository{public:  Repository() : _capacity(2), _emptynum(_capacity){}  Repository(int capacity) : _emptynum(capacity), _capacity(capacity){}  // success : when new_capacity > _capacity - _emptynum  bool set_capacity(int new_capacity){    boost::mutex::scoped_lock lock();    if (_capacity - _emptynum < new_capacity ){            _emptynum = new_capacity - _capacity + _emptynum;      _capacity = new_capacity;      return true;    }    return false;  }  bool empty(){    boost::mutex::scoped_lock lock(_mutexer);    return _is_empty();  }  void put(Product &product){    {      boost::mutex::scoped_lock lock(_mutexer);      while (_is_full()){        // unlock _mutexer and blocked until _condition_put.notifiy_one/all is called.        _condition_put.wait(_mutexer);       }      _products.push(product); // need implement the copy constructor and =       _emptynum--; // decrease empty position    }    _condition_get.notify_one(); // have put one, one another thread can get product now  }  void get(Product &product){    {      // lock this repository      boost::mutex::scoped_lock lock(_mutexer);      while (_is_empty()){        // unlock _mutexer and blocked until _condition_put.notifiy_one/all is called.        _condition_get.wait(_mutexer);      }      product = _products.front(); // need implement the copy constructor and =       _products.pop();      _emptynum++; // increase empty position    }    // have removed one product, one another thread can put product now    _condition_put.notify_one();   }private:  inline bool _is_full (){ return _emptynum ==         0; } // if have empty position  inline bool _is_empty(){ return _emptynum == _capacity; } // private:  int _capacity; // capacity of this repository  int _emptynum; // number of empty position  std::queue<Product> _products; // products in a FIFO queue  boost::mutex _mutexer; // race access  boost::condition _condition_put;   boost::condition _condition_get;};boost::mutex g_io_mutexer;boost::mutex g_mutexer;bool g_is_finished = false;Repository<int> g_repository(4);void producing(){  for (int i = 0; i < 100; i++){    {      boost::mutex::scoped_lock lock(g_io_mutexer);      std::cout << "Producing product : " << i << std::endl;    }    g_repository.put(i);  }  boost::mutex::scoped_lock lock(g_mutexer);  g_is_finished = true;}void consuming(){  int product;  while (true){    {      boost::mutex::scoped_lock lock(g_mutexer);      if (g_is_finished && g_repository.empty()){        break;      }    }    g_repository.get(product);    {      boost::mutex::scoped_lock lock(g_io_mutexer);      std::cout << "Consuming product : " << product << std::endl;    }  }}int main(){  boost::thread producer(producing);  boost::thread consumer_1(consuming);  boost::thread consumer_2(consuming);  producer.join();  consumer_1.join();  consumer_2.join();  return 0;}