| // |
| // resolver_service.hpp |
| // ~~~~~~~~~~~~~~~~~~~~ |
| // |
| // Copyright (c) 2003-2008 Christopher M. Kohlhoff (chris at kohlhoff dot com) |
| // |
| // Distributed under the Boost Software License, Version 1.0. (See accompanying |
| // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
| // |
| |
| #ifndef BOOST_ASIO_DETAIL_RESOLVER_SERVICE_HPP |
| #define BOOST_ASIO_DETAIL_RESOLVER_SERVICE_HPP |
| |
| #if defined(_MSC_VER) && (_MSC_VER >= 1200) |
| # pragma once |
| #endif // defined(_MSC_VER) && (_MSC_VER >= 1200) |
| |
| #include <boost/asio/detail/push_options.hpp> |
| |
| #include <boost/asio/detail/push_options.hpp> |
| #include <cstring> |
| #include <boost/scoped_ptr.hpp> |
| #include <boost/shared_ptr.hpp> |
| #include <boost/weak_ptr.hpp> |
| #include <boost/asio/detail/pop_options.hpp> |
| |
| #include <boost/asio/error.hpp> |
| #include <boost/asio/io_service.hpp> |
| #include <boost/asio/detail/bind_handler.hpp> |
| #include <boost/asio/detail/mutex.hpp> |
| #include <boost/asio/detail/noncopyable.hpp> |
| #include <boost/asio/detail/service_base.hpp> |
| #include <boost/asio/detail/socket_ops.hpp> |
| #include <boost/asio/detail/socket_types.hpp> |
| #include <boost/asio/detail/thread.hpp> |
| |
| namespace boost { |
| namespace asio { |
| namespace detail { |
| |
| template <typename Protocol> |
| class resolver_service |
| : public boost::asio::detail::service_base<resolver_service<Protocol> > |
| { |
| private: |
| // Helper class to perform exception-safe cleanup of addrinfo objects. |
| class auto_addrinfo |
| : private boost::asio::detail::noncopyable |
| { |
| public: |
| explicit auto_addrinfo(boost::asio::detail::addrinfo_type* ai) |
| : ai_(ai) |
| { |
| } |
| |
| ~auto_addrinfo() |
| { |
| if (ai_) |
| socket_ops::freeaddrinfo(ai_); |
| } |
| |
| operator boost::asio::detail::addrinfo_type*() |
| { |
| return ai_; |
| } |
| |
| private: |
| boost::asio::detail::addrinfo_type* ai_; |
| }; |
| |
| public: |
| // The implementation type of the resolver. The shared pointer is used as a |
| // cancellation token to indicate to the background thread that the operation |
| // has been cancelled. |
| typedef boost::shared_ptr<void> implementation_type; |
| struct noop_deleter { void operator()(void*) {} }; |
| |
| // The endpoint type. |
| typedef typename Protocol::endpoint endpoint_type; |
| |
| // The query type. |
| typedef typename Protocol::resolver_query query_type; |
| |
| // The iterator type. |
| typedef typename Protocol::resolver_iterator iterator_type; |
| |
| // Constructor. |
| resolver_service(boost::asio::io_service& io_service) |
| : boost::asio::detail::service_base< |
| resolver_service<Protocol> >(io_service), |
| mutex_(), |
| work_io_service_(new boost::asio::io_service), |
| work_(new boost::asio::io_service::work(*work_io_service_)), |
| work_thread_(0) |
| { |
| } |
| |
| // Destructor. |
| ~resolver_service() |
| { |
| shutdown_service(); |
| } |
| |
| // Destroy all user-defined handler objects owned by the service. |
| void shutdown_service() |
| { |
| work_.reset(); |
| if (work_io_service_) |
| { |
| work_io_service_->stop(); |
| if (work_thread_) |
| { |
| work_thread_->join(); |
| work_thread_.reset(); |
| } |
| work_io_service_.reset(); |
| } |
| } |
| |
| // Construct a new resolver implementation. |
| void construct(implementation_type& impl) |
| { |
| impl.reset(static_cast<void*>(0), noop_deleter()); |
| } |
| |
| // Destroy a resolver implementation. |
| void destroy(implementation_type&) |
| { |
| } |
| |
| // Cancel pending asynchronous operations. |
| void cancel(implementation_type& impl) |
| { |
| impl.reset(static_cast<void*>(0), noop_deleter()); |
| } |
| |
| // Resolve a query to a list of entries. |
| iterator_type resolve(implementation_type&, const query_type& query, |
| boost::system::error_code& ec) |
| { |
| boost::asio::detail::addrinfo_type* address_info = 0; |
| std::string host_name = query.host_name(); |
| std::string service_name = query.service_name(); |
| boost::asio::detail::addrinfo_type hints = query.hints(); |
| |
| socket_ops::getaddrinfo(host_name.length() ? host_name.c_str() : 0, |
| service_name.c_str(), &hints, &address_info, ec); |
| auto_addrinfo auto_address_info(address_info); |
| |
| if (ec) |
| return iterator_type(); |
| |
| return iterator_type::create(address_info, host_name, service_name); |
| } |
| |
| template <typename Handler> |
| class resolve_query_handler |
| { |
| public: |
| resolve_query_handler(implementation_type impl, const query_type& query, |
| boost::asio::io_service& io_service, Handler handler) |
| : impl_(impl), |
| query_(query), |
| io_service_(io_service), |
| work_(io_service), |
| handler_(handler) |
| { |
| } |
| |
| void operator()() |
| { |
| // Check if the operation has been cancelled. |
| if (impl_.expired()) |
| { |
| iterator_type iterator; |
| io_service_.post(boost::asio::detail::bind_handler(handler_, |
| boost::asio::error::operation_aborted, iterator)); |
| return; |
| } |
| |
| // Perform the blocking host resolution operation. |
| boost::asio::detail::addrinfo_type* address_info = 0; |
| std::string host_name = query_.host_name(); |
| std::string service_name = query_.service_name(); |
| boost::asio::detail::addrinfo_type hints = query_.hints(); |
| boost::system::error_code ec; |
| socket_ops::getaddrinfo(host_name.length() ? host_name.c_str() : 0, |
| service_name.c_str(), &hints, &address_info, ec); |
| auto_addrinfo auto_address_info(address_info); |
| |
| // Invoke the handler and pass the result. |
| iterator_type iterator; |
| if (!ec) |
| iterator = iterator_type::create(address_info, host_name, service_name); |
| io_service_.post(boost::asio::detail::bind_handler( |
| handler_, ec, iterator)); |
| } |
| |
| private: |
| boost::weak_ptr<void> impl_; |
| query_type query_; |
| boost::asio::io_service& io_service_; |
| boost::asio::io_service::work work_; |
| Handler handler_; |
| }; |
| |
| // Asynchronously resolve a query to a list of entries. |
| template <typename Handler> |
| void async_resolve(implementation_type& impl, const query_type& query, |
| Handler handler) |
| { |
| if (work_io_service_) |
| { |
| start_work_thread(); |
| work_io_service_->post( |
| resolve_query_handler<Handler>( |
| impl, query, this->get_io_service(), handler)); |
| } |
| } |
| |
| // Resolve an endpoint to a list of entries. |
| iterator_type resolve(implementation_type&, |
| const endpoint_type& endpoint, boost::system::error_code& ec) |
| { |
| // First try resolving with the service name. If that fails try resolving |
| // but allow the service to be returned as a number. |
| char host_name[NI_MAXHOST]; |
| char service_name[NI_MAXSERV]; |
| int flags = endpoint.protocol().type() == SOCK_DGRAM ? NI_DGRAM : 0; |
| socket_ops::getnameinfo(endpoint.data(), endpoint.size(), |
| host_name, NI_MAXHOST, service_name, NI_MAXSERV, flags, ec); |
| if (ec) |
| { |
| flags |= NI_NUMERICSERV; |
| socket_ops::getnameinfo(endpoint.data(), endpoint.size(), |
| host_name, NI_MAXHOST, service_name, NI_MAXSERV, flags, ec); |
| } |
| |
| if (ec) |
| return iterator_type(); |
| |
| return iterator_type::create(endpoint, host_name, service_name); |
| } |
| |
| template <typename Handler> |
| class resolve_endpoint_handler |
| { |
| public: |
| resolve_endpoint_handler(implementation_type impl, |
| const endpoint_type& endpoint, boost::asio::io_service& io_service, |
| Handler handler) |
| : impl_(impl), |
| endpoint_(endpoint), |
| io_service_(io_service), |
| work_(io_service), |
| handler_(handler) |
| { |
| } |
| |
| void operator()() |
| { |
| // Check if the operation has been cancelled. |
| if (impl_.expired()) |
| { |
| iterator_type iterator; |
| io_service_.post(boost::asio::detail::bind_handler(handler_, |
| boost::asio::error::operation_aborted, iterator)); |
| return; |
| } |
| |
| |
| // First try resolving with the service name. If that fails try resolving |
| // but allow the service to be returned as a number. |
| char host_name[NI_MAXHOST]; |
| char service_name[NI_MAXSERV]; |
| int flags = endpoint_.protocol().type() == SOCK_DGRAM ? NI_DGRAM : 0; |
| boost::system::error_code ec; |
| socket_ops::getnameinfo(endpoint_.data(), endpoint_.size(), |
| host_name, NI_MAXHOST, service_name, NI_MAXSERV, flags, ec); |
| if (ec) |
| { |
| flags |= NI_NUMERICSERV; |
| socket_ops::getnameinfo(endpoint_.data(), endpoint_.size(), |
| host_name, NI_MAXHOST, service_name, NI_MAXSERV, flags, ec); |
| } |
| |
| // Invoke the handler and pass the result. |
| iterator_type iterator; |
| if (!ec) |
| iterator = iterator_type::create(endpoint_, host_name, service_name); |
| io_service_.post(boost::asio::detail::bind_handler( |
| handler_, ec, iterator)); |
| } |
| |
| private: |
| boost::weak_ptr<void> impl_; |
| endpoint_type endpoint_; |
| boost::asio::io_service& io_service_; |
| boost::asio::io_service::work work_; |
| Handler handler_; |
| }; |
| |
| // Asynchronously resolve an endpoint to a list of entries. |
| template <typename Handler> |
| void async_resolve(implementation_type& impl, const endpoint_type& endpoint, |
| Handler handler) |
| { |
| if (work_io_service_) |
| { |
| start_work_thread(); |
| work_io_service_->post( |
| resolve_endpoint_handler<Handler>( |
| impl, endpoint, this->get_io_service(), handler)); |
| } |
| } |
| |
| private: |
| // Helper class to run the work io_service in a thread. |
| class work_io_service_runner |
| { |
| public: |
| work_io_service_runner(boost::asio::io_service& io_service) |
| : io_service_(io_service) {} |
| void operator()() { io_service_.run(); } |
| private: |
| boost::asio::io_service& io_service_; |
| }; |
| |
| // Start the work thread if it's not already running. |
| void start_work_thread() |
| { |
| boost::asio::detail::mutex::scoped_lock lock(mutex_); |
| if (!work_thread_) |
| { |
| work_thread_.reset(new boost::asio::detail::thread( |
| work_io_service_runner(*work_io_service_))); |
| } |
| } |
| |
| // Mutex to protect access to internal data. |
| boost::asio::detail::mutex mutex_; |
| |
| // Private io_service used for performing asynchronous host resolution. |
| boost::scoped_ptr<boost::asio::io_service> work_io_service_; |
| |
| // Work for the private io_service to perform. |
| boost::scoped_ptr<boost::asio::io_service::work> work_; |
| |
| // Thread used for running the work io_service's run loop. |
| boost::scoped_ptr<boost::asio::detail::thread> work_thread_; |
| }; |
| |
| } // namespace detail |
| } // namespace asio |
| } // namespace boost |
| |
| #include <boost/asio/detail/pop_options.hpp> |
| |
| #endif // BOOST_ASIO_DETAIL_RESOLVER_SERVICE_HPP |