淺談c++中的開源架構類目--分享二（架構）

　　這個系列Lee哥會分享一些c++中的開源架構。

　　主要從TCP協定棧、架構、并發性、資料庫、國際化、壓縮、日志、多媒體庫、序列化、XML庫、腳本、Json庫、數學庫、安全、WEB應用架構、網絡庫、異步事件等方面來分享。分享的内容不僅限于自己來寫，有會借鑒網上大牛們的一些文章與大家分享。

　　之前我們講了TCP，今天我們來講一講架構。這裡Lee哥把架構的技術分成4個子產品。

　　1.facebook開發和使用的開源c++庫folly

　　2.高性能網絡應用程式c++11 evented IO LibSourcey

　　3.企業應用程式開發架構libphenom

　　4.通用C++庫的集合Boost

　　對于TCP協定棧想了解的朋友可以看一下

　　bilibili/video/av57632138

　　今天分享的是：boost asio 實作一個TCP服務端線程池

　　原文轉載于blog.csdn/hust_wangyajun/article/details/52571752

　　tcp的伺服器端綁定并監聽端口，如果用戶端比較少，可以對每個用戶端建立一個線程進行通訊處理，但當用戶端的數量比較龐大的時候這種思路就變得不可行，一方面線程切換的開銷太大，另一方面，多數線程并不出于“工作”狀态，

賣二手手機靓号平台

長期出于等待事件的狀态。這時，可以使用線程池的架構加快處理速度。

　　廢話少說，直接上代碼

　　#include

　　using boost::asio::ip::tcp;

　　class handler_allocator

　　: private boost::noncopyable

　　{

　　public:

　　handler_allocator()

　　: in_use_(false)

　　}

　　void* allocate(std::size_t size)

　　if (!in_use_ && size < storage_.size)

　　in_use_=true;

　　return storage_.address();

　　else

　　return ::operator new(size);

　　void deallocate(void* pointer)

　　if (pointer==storage_.address())

　　in_use_=false;

　　::operator delete(pointer);

　　private:

　　// Storage space used for handler-based custom memory allocation.

　　boost::aligned_storage<1024> storage_;

　　// Whether the handler-based custom allocation storage has been used.

　　bool in_use_;

　　};

　　template

　　class custom_alloc_handler

　　custom_alloc_handler(handler_allocator& a, Handler h)

　　: allocator_(a),

　　handler_(h)

　　void operator()(Arg1 arg1)

　　handler_(arg1);

　　void operator()(Arg1 arg1, Arg2 arg2)

　　handler_(arg1, arg2);

　　friend void* asio_handler_allocate(std::size_t size,

　　custom_alloc_handler* this_handler)

　　return this_handler->allocator_.allocate(size);

　　friend void asio_handler_deallocate(void pointer, std::size_t /size*/,

　　this_handler->allocator_.deallocate(pointer);

　　handler_allocator& allocator_;

　　Handler handler_;

　　// Helper function to wrap a handler object to add custom allocation.

　　inline custom_alloc_handler make_custom_alloc_handler(

　　handler_allocator& a, Handler h)

　　return custom_alloc_handler(a, h);

　　/// A pool of io_service objects.

　　class io_service_pool

　　/// Construct the io_service pool.

　　explicit io_service_pool(std::size_t pool_size) : next_io_service_(0)

　　if (pool_size==0)

　　throw std::runtime_error("io_service_pool size is 0");

　　// Give all the io_services work to do so that their run() functions will not

　　// exit until they are explicitly stopped.

　　for (std::size_t i=0; i < pool_size; ++i)

　　io_service_ptr io_service(new boost::asio::io_service);

　　work_ptr work(new boost::asio::io_service::work(*io_service));

　　io_services_.push_back(io_service);

　　work_.push_back(work);

　　// Run all io_service objects in the pool.

　　void run()

　　// Create a pool of threads to run all of the io_services.

　　std::vector > threads;

　　for (std::size_t i=0; i < io_services_.size(); ++i)

　　boost::shared_ptr thread(new boost::thread(

　　boost::bind(&boost::asio::io_service::run, io_services_[i])));

　　threads.push_back(thread);

　　// Wait for all threads in the pool to exit.

　　for (std::size_t i=0; i < threads.size(); ++i)

　　threads[i]->join();

　　// Stop all io_service objects in the pool.

　　void stop()

　　// Explicitly stop all io_services.

　　io_services_[i]->stop();

　　// Get an io_service to use.

　　boost::asio::io_service& get_io_service()

　　// Use a round-robin scheme to choose the next io_service to use.

　　boost::asio::io_service& io_service=*io_services_[next_io_service_];

　　++next_io_service_;

　　if (next_io_service_==io_services_.size())

　　next_io_service_=0;

　　return io_service;

　　typedef boost::shared_ptr io_service_ptr;

　　typedef boost::shared_ptr work_ptr;

　　/// The pool of io_services.

　　std::vector io_services_;

　　/// The work that keeps the io_services running.

　　std::vector work_;

　　/// The next io_service to use for a connection.

　　std::size_t next_io_service_;

　　class session

　　: public boost::enable_shared_from_this

　　session(boost::asio::io_service& work_service

　　, boost::asio::io_service& io_service)

　　: socket_(io_service)

　　, io_work_service(work_service)

　　tcp::socket& socket()

　　return socket_;

　　void start()

　　boost::system::error_code error;

　　handle_write(error);

　　socket_.async_read_some(boost::asio::buffer(data_),

　　make_custom_alloc_handler(allocator_,

　　boost::bind(&session::handle_read,

　　shared_from_this(),

　　boost::asio::placeholders::error,

　　boost::asio::placeholders::bytes_transferred)));

　　void handle_read(const boost::system::error_code& error,

　　size_t bytes_transferred)

　　if (!error)

　　boost::shared_ptr > buf(new std::vector);

　　buf->resize(bytes_transferred);

　　std::copy(data_.begin(), data_.begin() + bytes_transferred, buf->begin());

　　io_work_service.post(boost::bind(&session::on_receive

　　, shared_from_this(), buf, bytes_transferred));

　　void handle_write(const boost::system::error_code& error)

　　char notice[]="Welcome to Connect to Hiper Service";

　　size_t num;

　　try

　　num=socket_.send(boost::asio::buffer(notice));

　　catch(std::exception &e)

　　std::cout<<"exception: "<

　　if(num>0)

　　std::cout<<"send : "<< notice << std::endl;

　　void on_receive(boost::shared_ptr > buffers

　　, size_t bytes_transferred)

　　char data_stream=&(buffers->begin());

　　// in here finish the work.

　　std::cout << "receive :" << bytes_transferred << " bytes." <<

　　"message :" << data_stream << std::endl;

　　// The io_service used to finish the work.

　　boost::asio::io_service& io_work_service;

　　// The socket used to communicate with the client.

　　tcp::socket socket_;

　　// Buffer used to store data received from the client.

　　boost::array data_;

　　// The allocator to use for handler-based custom memory allocation.

　　handler_allocator allocator_;

　　typedef boost::shared_ptr session_ptr;

　　class server

　　server(short port, std::size_t io_service_pool_size)

　　: io_service_pool_(io_service_pool_size)

　　, io_service_work_pool_(io_service_pool_size)

　　, acceptor_(io_service_pool_.get_io_service(), tcp::endpoint(tcp::v4(), port))

　　session_ptr new_session(new session(io_service_work_pool_.get_io_service()

　　, io_service_pool_.get_io_service()));

　　acceptor_.async_accept(new_session->socket(),

　　boost::bind(&server::handle_accept, this, new_session,

　　boost::asio::placeholders::error));

　　void handle_accept(session_ptr new_session,

　　const boost::system::error_code& error)

　　new_session->start();

　　new_session.reset(new session(io_service_work_pool_.get_io_service()

　　io_thread_.reset(new boost::thread(boost::bind(&io_service_pool::run

　　, &io_service_pool_)));

　　work_thread_.reset(new boost::thread(boost::bind(&io_service_pool::run

　　, &io_service_work_pool_)));

　　io_service_pool_.stop();

　　io_service_work_pool_.stop();

　　io_thread_->join();

　　work_thread_->join();

　　boost::shared_ptr io_thread_;

　　boost::shared_ptr work_thread_;

　　io_service_pool io_service_pool_;

　　io_service_pool io_service_work_pool_;

　　tcp::acceptor acceptor_;