boost/asio/ip/basic_resolver.hpp
// // ip/basic_resolver.hpp // ~~~~~~~~~~~~~~~~~~~~~ // // Copyright (c) 2003-2022 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_IP_BASIC_RESOLVER_HPP #define BOOST_ASIO_IP_BASIC_RESOLVER_HPP #if defined(_MSC_VER) && (_MSC_VER >= 1200) # pragma once #endif // defined(_MSC_VER) && (_MSC_VER >= 1200) #include <boost/asio/detail/config.hpp> #include <string> #include <boost/asio/any_io_executor.hpp> #include <boost/asio/async_result.hpp> #include <boost/asio/detail/handler_type_requirements.hpp> #include <boost/asio/detail/io_object_impl.hpp> #include <boost/asio/detail/non_const_lvalue.hpp> #include <boost/asio/detail/string_view.hpp> #include <boost/asio/detail/throw_error.hpp> #include <boost/asio/error.hpp> #include <boost/asio/execution_context.hpp> #include <boost/asio/ip/basic_resolver_iterator.hpp> #include <boost/asio/ip/basic_resolver_query.hpp> #include <boost/asio/ip/basic_resolver_results.hpp> #include <boost/asio/ip/resolver_base.hpp> #if defined(BOOST_ASIO_WINDOWS_RUNTIME) # include <boost/asio/detail/winrt_resolver_service.hpp> #else # include <boost/asio/detail/resolver_service.hpp> #endif #if defined(BOOST_ASIO_HAS_MOVE) # include <utility> #endif // defined(BOOST_ASIO_HAS_MOVE) #include <boost/asio/detail/push_options.hpp> namespace boost { namespace asio { namespace ip { #if !defined(BOOST_ASIO_IP_BASIC_RESOLVER_FWD_DECL) #define BOOST_ASIO_IP_BASIC_RESOLVER_FWD_DECL // Forward declaration with defaulted arguments. template <typename InternetProtocol, typename Executor = any_io_executor> class basic_resolver; #endif // !defined(BOOST_ASIO_IP_BASIC_RESOLVER_FWD_DECL) /// Provides endpoint resolution functionality. /** * The basic_resolver class template provides the ability to resolve a query * to a list of endpoints. * * @par Thread Safety * @e Distinct @e objects: Safe.@n * @e Shared @e objects: Unsafe. */ template <typename InternetProtocol, typename Executor> class basic_resolver : public resolver_base { public: /// The type of the executor associated with the object. typedef Executor executor_type; /// Rebinds the resolver type to another executor. template <typename Executor1> struct rebind_executor { /// The resolver type when rebound to the specified executor. typedef basic_resolver<InternetProtocol, Executor1> other; }; /// The protocol type. typedef InternetProtocol protocol_type; /// The endpoint type. typedef typename InternetProtocol::endpoint endpoint_type; #if !defined(BOOST_ASIO_NO_DEPRECATED) /// (Deprecated.) The query type. typedef basic_resolver_query<InternetProtocol> query; /// (Deprecated.) The iterator type. typedef basic_resolver_iterator<InternetProtocol> iterator; #endif // !defined(BOOST_ASIO_NO_DEPRECATED) /// The results type. typedef basic_resolver_results<InternetProtocol> results_type; /// Construct with executor. /** * This constructor creates a basic_resolver. * * @param ex The I/O executor that the resolver will use, by default, to * dispatch handlers for any asynchronous operations performed on the * resolver. */ explicit basic_resolver(const executor_type& ex) : impl_(0, ex) { } /// Construct with execution context. /** * This constructor creates a basic_resolver. * * @param context An execution context which provides the I/O executor that * the resolver will use, by default, to dispatch handlers for any * asynchronous operations performed on the resolver. */ template <typename ExecutionContext> explicit basic_resolver(ExecutionContext& context, typename constraint< is_convertible<ExecutionContext&, execution_context&>::value >::type = 0) : impl_(0, 0, context) { } #if defined(BOOST_ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION) /// Move-construct a basic_resolver from another. /** * This constructor moves a resolver from one object to another. * * @param other The other basic_resolver object from which the move will * occur. * * @note Following the move, the moved-from object is in the same state as if * constructed using the @c basic_resolver(const executor_type&) constructor. */ basic_resolver(basic_resolver&& other) : impl_(std::move(other.impl_)) { } // All resolvers have access to each other's implementations. template <typename InternetProtocol1, typename Executor1> friend class basic_resolver; /// Move-construct a basic_resolver from another. /** * This constructor moves a resolver from one object to another. * * @param other The other basic_resolver object from which the move will * occur. * * @note Following the move, the moved-from object is in the same state as if * constructed using the @c basic_resolver(const executor_type&) constructor. */ template <typename Executor1> basic_resolver(basic_resolver<InternetProtocol, Executor1>&& other, typename constraint< is_convertible<Executor1, Executor>::value >::type = 0) : impl_(std::move(other.impl_)) { } /// Move-assign a basic_resolver from another. /** * This assignment operator moves a resolver from one object to another. * Cancels any outstanding asynchronous operations associated with the target * object. * * @param other The other basic_resolver object from which the move will * occur. * * @note Following the move, the moved-from object is in the same state as if * constructed using the @c basic_resolver(const executor_type&) constructor. */ basic_resolver& operator=(basic_resolver&& other) { impl_ = std::move(other.impl_); return *this; } /// Move-assign a basic_resolver from another. /** * This assignment operator moves a resolver from one object to another. * Cancels any outstanding asynchronous operations associated with the target * object. * * @param other The other basic_resolver object from which the move will * occur. * * @note Following the move, the moved-from object is in the same state as if * constructed using the @c basic_resolver(const executor_type&) constructor. */ template <typename Executor1> typename constraint< is_convertible<Executor1, Executor>::value, basic_resolver& >::type operator=(basic_resolver<InternetProtocol, Executor1>&& other) { basic_resolver tmp(std::move(other)); impl_ = std::move(tmp.impl_); return *this; } #endif // defined(BOOST_ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION) /// Destroys the resolver. /** * This function destroys the resolver, cancelling any outstanding * asynchronous wait operations associated with the resolver as if by calling * @c cancel. */ ~basic_resolver() { } /// Get the executor associated with the object. executor_type get_executor() BOOST_ASIO_NOEXCEPT { return impl_.get_executor(); } /// Cancel any asynchronous operations that are waiting on the resolver. /** * This function forces the completion of any pending asynchronous * operations on the host resolver. The handler for each cancelled operation * will be invoked with the boost::asio::error::operation_aborted error code. */ void cancel() { return impl_.get_service().cancel(impl_.get_implementation()); } #if !defined(BOOST_ASIO_NO_DEPRECATED) /// (Deprecated: Use overload with separate host and service parameters.) /// Perform forward resolution of a query to a list of entries. /** * This function is used to resolve a query into a list of endpoint entries. * * @param q A query object that determines what endpoints will be returned. * * @returns A range object representing the list of endpoint entries. A * successful call to this function is guaranteed to return a non-empty * range. * * @throws boost::system::system_error Thrown on failure. */ results_type resolve(const query& q) { boost::system::error_code ec; results_type r = impl_.get_service().resolve( impl_.get_implementation(), q, ec); boost::asio::detail::throw_error(ec, "resolve"); return r; } /// (Deprecated: Use overload with separate host and service parameters.) /// Perform forward resolution of a query to a list of entries. /** * This function is used to resolve a query into a list of endpoint entries. * * @param q A query object that determines what endpoints will be returned. * * @param ec Set to indicate what error occurred, if any. * * @returns A range object representing the list of endpoint entries. An * empty range is returned if an error occurs. A successful call to this * function is guaranteed to return a non-empty range. */ results_type resolve(const query& q, boost::system::error_code& ec) { return impl_.get_service().resolve(impl_.get_implementation(), q, ec); } #endif // !defined(BOOST_ASIO_NO_DEPRECATED) /// Perform forward resolution of a query to a list of entries. /** * This function is used to resolve host and service names into a list of * endpoint entries. * * @param host A string identifying a location. May be a descriptive name or * a numeric address string. If an empty string and the passive flag has been * specified, the resolved endpoints are suitable for local service binding. * If an empty string and passive is not specified, the resolved endpoints * will use the loopback address. * * @param service A string identifying the requested service. This may be a * descriptive name or a numeric string corresponding to a port number. May * be an empty string, in which case all resolved endpoints will have a port * number of 0. * * @returns A range object representing the list of endpoint entries. A * successful call to this function is guaranteed to return a non-empty * range. * * @throws boost::system::system_error Thrown on failure. * * @note On POSIX systems, host names may be locally defined in the file * <tt>/etc/hosts</tt>. On Windows, host names may be defined in the file * <tt>c:\\windows\\system32\\drivers\\etc\\hosts</tt>. Remote host name * resolution is performed using DNS. Operating systems may use additional * locations when resolving host names (such as NETBIOS names on Windows). * * On POSIX systems, service names are typically defined in the file * <tt>/etc/services</tt>. On Windows, service names may be found in the file * <tt>c:\\windows\\system32\\drivers\\etc\\services</tt>. Operating systems * may use additional locations when resolving service names. */ results_type resolve(BOOST_ASIO_STRING_VIEW_PARAM host, BOOST_ASIO_STRING_VIEW_PARAM service) { return resolve(host, service, resolver_base::flags()); } /// Perform forward resolution of a query to a list of entries. /** * This function is used to resolve host and service names into a list of * endpoint entries. * * @param host A string identifying a location. May be a descriptive name or * a numeric address string. If an empty string and the passive flag has been * specified, the resolved endpoints are suitable for local service binding. * If an empty string and passive is not specified, the resolved endpoints * will use the loopback address. * * @param service A string identifying the requested service. This may be a * descriptive name or a numeric string corresponding to a port number. May * be an empty string, in which case all resolved endpoints will have a port * number of 0. * * @param ec Set to indicate what error occurred, if any. * * @returns A range object representing the list of endpoint entries. An * empty range is returned if an error occurs. A successful call to this * function is guaranteed to return a non-empty range. * * @note On POSIX systems, host names may be locally defined in the file * <tt>/etc/hosts</tt>. On Windows, host names may be defined in the file * <tt>c:\\windows\\system32\\drivers\\etc\\hosts</tt>. Remote host name * resolution is performed using DNS. Operating systems may use additional * locations when resolving host names (such as NETBIOS names on Windows). * * On POSIX systems, service names are typically defined in the file * <tt>/etc/services</tt>. On Windows, service names may be found in the file * <tt>c:\\windows\\system32\\drivers\\etc\\services</tt>. Operating systems * may use additional locations when resolving service names. */ results_type resolve(BOOST_ASIO_STRING_VIEW_PARAM host, BOOST_ASIO_STRING_VIEW_PARAM service, boost::system::error_code& ec) { return resolve(host, service, resolver_base::flags(), ec); } /// Perform forward resolution of a query to a list of entries. /** * This function is used to resolve host and service names into a list of * endpoint entries. * * @param host A string identifying a location. May be a descriptive name or * a numeric address string. If an empty string and the passive flag has been * specified, the resolved endpoints are suitable for local service binding. * If an empty string and passive is not specified, the resolved endpoints * will use the loopback address. * * @param service A string identifying the requested service. This may be a * descriptive name or a numeric string corresponding to a port number. May * be an empty string, in which case all resolved endpoints will have a port * number of 0. * * @param resolve_flags A set of flags that determine how name resolution * should be performed. The default flags are suitable for communication with * remote hosts. See the @ref resolver_base documentation for the set of * available flags. * * @returns A range object representing the list of endpoint entries. A * successful call to this function is guaranteed to return a non-empty * range. * * @throws boost::system::system_error Thrown on failure. * * @note On POSIX systems, host names may be locally defined in the file * <tt>/etc/hosts</tt>. On Windows, host names may be defined in the file * <tt>c:\\windows\\system32\\drivers\\etc\\hosts</tt>. Remote host name * resolution is performed using DNS. Operating systems may use additional * locations when resolving host names (such as NETBIOS names on Windows). * * On POSIX systems, service names are typically defined in the file * <tt>/etc/services</tt>. On Windows, service names may be found in the file * <tt>c:\\windows\\system32\\drivers\\etc\\services</tt>. Operating systems * may use additional locations when resolving service names. */ results_type resolve(BOOST_ASIO_STRING_VIEW_PARAM host, BOOST_ASIO_STRING_VIEW_PARAM service, resolver_base::flags resolve_flags) { boost::system::error_code ec; basic_resolver_query<protocol_type> q(static_cast<std::string>(host), static_cast<std::string>(service), resolve_flags); results_type r = impl_.get_service().resolve( impl_.get_implementation(), q, ec); boost::asio::detail::throw_error(ec, "resolve"); return r; } /// Perform forward resolution of a query to a list of entries. /** * This function is used to resolve host and service names into a list of * endpoint entries. * * @param host A string identifying a location. May be a descriptive name or * a numeric address string. If an empty string and the passive flag has been * specified, the resolved endpoints are suitable for local service binding. * If an empty string and passive is not specified, the resolved endpoints * will use the loopback address. * * @param service A string identifying the requested service. This may be a * descriptive name or a numeric string corresponding to a port number. May * be an empty string, in which case all resolved endpoints will have a port * number of 0. * * @param resolve_flags A set of flags that determine how name resolution * should be performed. The default flags are suitable for communication with * remote hosts. See the @ref resolver_base documentation for the set of * available flags. * * @param ec Set to indicate what error occurred, if any. * * @returns A range object representing the list of endpoint entries. An * empty range is returned if an error occurs. A successful call to this * function is guaranteed to return a non-empty range. * * @note On POSIX systems, host names may be locally defined in the file * <tt>/etc/hosts</tt>. On Windows, host names may be defined in the file * <tt>c:\\windows\\system32\\drivers\\etc\\hosts</tt>. Remote host name * resolution is performed using DNS. Operating systems may use additional * locations when resolving host names (such as NETBIOS names on Windows). * * On POSIX systems, service names are typically defined in the file * <tt>/etc/services</tt>. On Windows, service names may be found in the file * <tt>c:\\windows\\system32\\drivers\\etc\\services</tt>. Operating systems * may use additional locations when resolving service names. */ results_type resolve(BOOST_ASIO_STRING_VIEW_PARAM host, BOOST_ASIO_STRING_VIEW_PARAM service, resolver_base::flags resolve_flags, boost::system::error_code& ec) { basic_resolver_query<protocol_type> q(static_cast<std::string>(host), static_cast<std::string>(service), resolve_flags); return impl_.get_service().resolve(impl_.get_implementation(), q, ec); } /// Perform forward resolution of a query to a list of entries. /** * This function is used to resolve host and service names into a list of * endpoint entries. * * @param protocol A protocol object, normally representing either the IPv4 or * IPv6 version of an internet protocol. * * @param host A string identifying a location. May be a descriptive name or * a numeric address string. If an empty string and the passive flag has been * specified, the resolved endpoints are suitable for local service binding. * If an empty string and passive is not specified, the resolved endpoints * will use the loopback address. * * @param service A string identifying the requested service. This may be a * descriptive name or a numeric string corresponding to a port number. May * be an empty string, in which case all resolved endpoints will have a port * number of 0. * * @returns A range object representing the list of endpoint entries. A * successful call to this function is guaranteed to return a non-empty * range. * * @throws boost::system::system_error Thrown on failure. * * @note On POSIX systems, host names may be locally defined in the file * <tt>/etc/hosts</tt>. On Windows, host names may be defined in the file * <tt>c:\\windows\\system32\\drivers\\etc\\hosts</tt>. Remote host name * resolution is performed using DNS. Operating systems may use additional * locations when resolving host names (such as NETBIOS names on Windows). * * On POSIX systems, service names are typically defined in the file * <tt>/etc/services</tt>. On Windows, service names may be found in the file * <tt>c:\\windows\\system32\\drivers\\etc\\services</tt>. Operating systems * may use additional locations when resolving service names. */ results_type resolve(const protocol_type& protocol, BOOST_ASIO_STRING_VIEW_PARAM host, BOOST_ASIO_STRING_VIEW_PARAM service) { return resolve(protocol, host, service, resolver_base::flags()); } /// Perform forward resolution of a query to a list of entries. /** * This function is used to resolve host and service names into a list of * endpoint entries. * * @param protocol A protocol object, normally representing either the IPv4 or * IPv6 version of an internet protocol. * * @param host A string identifying a location. May be a descriptive name or * a numeric address string. If an empty string and the passive flag has been * specified, the resolved endpoints are suitable for local service binding. * If an empty string and passive is not specified, the resolved endpoints * will use the loopback address. * * @param service A string identifying the requested service. This may be a * descriptive name or a numeric string corresponding to a port number. May * be an empty string, in which case all resolved endpoints will have a port * number of 0. * * @param ec Set to indicate what error occurred, if any. * * @returns A range object representing the list of endpoint entries. An * empty range is returned if an error occurs. A successful call to this * function is guaranteed to return a non-empty range. * * @note On POSIX systems, host names may be locally defined in the file * <tt>/etc/hosts</tt>. On Windows, host names may be defined in the file * <tt>c:\\windows\\system32\\drivers\\etc\\hosts</tt>. Remote host name * resolution is performed using DNS. Operating systems may use additional * locations when resolving host names (such as NETBIOS names on Windows). * * On POSIX systems, service names are typically defined in the file * <tt>/etc/services</tt>. On Windows, service names may be found in the file * <tt>c:\\windows\\system32\\drivers\\etc\\services</tt>. Operating systems * may use additional locations when resolving service names. */ results_type resolve(const protocol_type& protocol, BOOST_ASIO_STRING_VIEW_PARAM host, BOOST_ASIO_STRING_VIEW_PARAM service, boost::system::error_code& ec) { return resolve(protocol, host, service, resolver_base::flags(), ec); } /// Perform forward resolution of a query to a list of entries. /** * This function is used to resolve host and service names into a list of * endpoint entries. * * @param protocol A protocol object, normally representing either the IPv4 or * IPv6 version of an internet protocol. * * @param host A string identifying a location. May be a descriptive name or * a numeric address string. If an empty string and the passive flag has been * specified, the resolved endpoints are suitable for local service binding. * If an empty string and passive is not specified, the resolved endpoints * will use the loopback address. * * @param service A string identifying the requested service. This may be a * descriptive name or a numeric string corresponding to a port number. May * be an empty string, in which case all resolved endpoints will have a port * number of 0. * * @param resolve_flags A set of flags that determine how name resolution * should be performed. The default flags are suitable for communication with * remote hosts. See the @ref resolver_base documentation for the set of * available flags. * * @returns A range object representing the list of endpoint entries. A * successful call to this function is guaranteed to return a non-empty * range. * * @throws boost::system::system_error Thrown on failure. * * @note On POSIX systems, host names may be locally defined in the file * <tt>/etc/hosts</tt>. On Windows, host names may be defined in the file * <tt>c:\\windows\\system32\\drivers\\etc\\hosts</tt>. Remote host name * resolution is performed using DNS. Operating systems may use additional * locations when resolving host names (such as NETBIOS names on Windows). * * On POSIX systems, service names are typically defined in the file * <tt>/etc/services</tt>. On Windows, service names may be found in the file * <tt>c:\\windows\\system32\\drivers\\etc\\services</tt>. Operating systems * may use additional locations when resolving service names. */ results_type resolve(const protocol_type& protocol, BOOST_ASIO_STRING_VIEW_PARAM host, BOOST_ASIO_STRING_VIEW_PARAM service, resolver_base::flags resolve_flags) { boost::system::error_code ec; basic_resolver_query<protocol_type> q( protocol, static_cast<std::string>(host), static_cast<std::string>(service), resolve_flags); results_type r = impl_.get_service().resolve( impl_.get_implementation(), q, ec); boost::asio::detail::throw_error(ec, "resolve"); return r; } /// Perform forward resolution of a query to a list of entries. /** * This function is used to resolve host and service names into a list of * endpoint entries. * * @param protocol A protocol object, normally representing either the IPv4 or * IPv6 version of an internet protocol. * * @param host A string identifying a location. May be a descriptive name or * a numeric address string. If an empty string and the passive flag has been * specified, the resolved endpoints are suitable for local service binding. * If an empty string and passive is not specified, the resolved endpoints * will use the loopback address. * * @param service A string identifying the requested service. This may be a * descriptive name or a numeric string corresponding to a port number. May * be an empty string, in which case all resolved endpoints will have a port * number of 0. * * @param resolve_flags A set of flags that determine how name resolution * should be performed. The default flags are suitable for communication with * remote hosts. See the @ref resolver_base documentation for the set of * available flags. * * @param ec Set to indicate what error occurred, if any. * * @returns A range object representing the list of endpoint entries. An * empty range is returned if an error occurs. A successful call to this * function is guaranteed to return a non-empty range. * * @note On POSIX systems, host names may be locally defined in the file * <tt>/etc/hosts</tt>. On Windows, host names may be defined in the file * <tt>c:\\windows\\system32\\drivers\\etc\\hosts</tt>. Remote host name * resolution is performed using DNS. Operating systems may use additional * locations when resolving host names (such as NETBIOS names on Windows). * * On POSIX systems, service names are typically defined in the file * <tt>/etc/services</tt>. On Windows, service names may be found in the file * <tt>c:\\windows\\system32\\drivers\\etc\\services</tt>. Operating systems * may use additional locations when resolving service names. */ results_type resolve(const protocol_type& protocol, BOOST_ASIO_STRING_VIEW_PARAM host, BOOST_ASIO_STRING_VIEW_PARAM service, resolver_base::flags resolve_flags, boost::system::error_code& ec) { basic_resolver_query<protocol_type> q( protocol, static_cast<std::string>(host), static_cast<std::string>(service), resolve_flags); return impl_.get_service().resolve(impl_.get_implementation(), q, ec); } #if !defined(BOOST_ASIO_NO_DEPRECATED) /// (Deprecated: Use overload with separate host and service parameters.) /// Asynchronously perform forward resolution of a query to a list of entries. /** * This function is used to asynchronously resolve a query into a list of * endpoint entries. It is an initiating function for an @ref * asynchronous_operation, and always returns immediately. * * @param q A query object that determines what endpoints will be returned. * * @param token The @ref completion_token that will be used to produce a * completion handler, which will be called when the resolve completes. * Potential completion tokens include @ref use_future, @ref use_awaitable, * @ref yield_context, or a function object with the correct completion * signature. The function signature of the completion handler must be: * @code void handler( * const boost::system::error_code& error, // Result of operation. * resolver::results_type results // Resolved endpoints as a range. * ); @endcode * Regardless of whether the asynchronous operation completes immediately or * not, the completion handler will not be invoked from within this function. * On immediate completion, invocation of the handler will be performed in a * manner equivalent to using boost::asio::post(). * * A successful resolve operation is guaranteed to pass a non-empty range to * the handler. * * @par Completion Signature * @code void(boost::system::error_code, results_type) @endcode */ template < BOOST_ASIO_COMPLETION_TOKEN_FOR(void (boost::system::error_code, results_type)) ResolveToken BOOST_ASIO_DEFAULT_COMPLETION_TOKEN_TYPE(executor_type)> BOOST_ASIO_INITFN_AUTO_RESULT_TYPE(ResolveToken, void (boost::system::error_code, results_type)) async_resolve(const query& q, BOOST_ASIO_MOVE_ARG(ResolveToken) token BOOST_ASIO_DEFAULT_COMPLETION_TOKEN(executor_type)) { return boost::asio::async_initiate<ResolveToken, void (boost::system::error_code, results_type)>( initiate_async_resolve(this), token, q); } #endif // !defined(BOOST_ASIO_NO_DEPRECATED) /// Asynchronously perform forward resolution of a query to a list of entries. /** * This function is used to resolve host and service names into a list of * endpoint entries. * * @param host A string identifying a location. May be a descriptive name or * a numeric address string. If an empty string and the passive flag has been * specified, the resolved endpoints are suitable for local service binding. * If an empty string and passive is not specified, the resolved endpoints * will use the loopback address. * * @param service A string identifying the requested service. This may be a * descriptive name or a numeric string corresponding to a port number. May * be an empty string, in which case all resolved endpoints will have a port * number of 0. * * @param token The @ref completion_token that will be used to produce a * completion handler, which will be called when the resolve completes. * Potential completion tokens include @ref use_future, @ref use_awaitable, * @ref yield_context, or a function object with the correct completion * signature. The function signature of the completion handler must be: * @code void handler( * const boost::system::error_code& error, // Result of operation. * resolver::results_type results // Resolved endpoints as a range. * ); @endcode * Regardless of whether the asynchronous operation completes immediately or * not, the completion handler will not be invoked from within this function. * On immediate completion, invocation of the handler will be performed in a * manner equivalent to using boost::asio::post(). * * A successful resolve operation is guaranteed to pass a non-empty range to * the handler. * * @par Completion Signature * @code void(boost::system::error_code, results_type) @endcode * * @note On POSIX systems, host names may be locally defined in the file * <tt>/etc/hosts</tt>. On Windows, host names may be defined in the file * <tt>c:\\windows\\system32\\drivers\\etc\\hosts</tt>. Remote host name * resolution is performed using DNS. Operating systems may use additional * locations when resolving host names (such as NETBIOS names on Windows). * * On POSIX systems, service names are typically defined in the file * <tt>/etc/services</tt>. On Windows, service names may be found in the file * <tt>c:\\windows\\system32\\drivers\\etc\\services</tt>. Operating systems * may use additional locations when resolving service names. */ template < BOOST_ASIO_COMPLETION_TOKEN_FOR(void (boost::system::error_code, results_type)) ResolveToken BOOST_ASIO_DEFAULT_COMPLETION_TOKEN_TYPE(executor_type)> BOOST_ASIO_INITFN_AUTO_RESULT_TYPE(ResolveToken, void (boost::system::error_code, results_type)) async_resolve(BOOST_ASIO_STRING_VIEW_PARAM host, BOOST_ASIO_STRING_VIEW_PARAM service, BOOST_ASIO_MOVE_ARG(ResolveToken) token BOOST_ASIO_DEFAULT_COMPLETION_TOKEN(executor_type)) { return async_resolve(host, service, resolver_base::flags(), BOOST_ASIO_MOVE_CAST(ResolveToken)(token)); } /// Asynchronously perform forward resolution of a query to a list of entries. /** * This function is used to resolve host and service names into a list of * endpoint entries. It is an initiating function for an @ref * asynchronous_operation, and always returns immediately. * * @param host A string identifying a location. May be a descriptive name or * a numeric address string. If an empty string and the passive flag has been * specified, the resolved endpoints are suitable for local service binding. * If an empty string and passive is not specified, the resolved endpoints * will use the loopback address. * * @param service A string identifying the requested service. This may be a * descriptive name or a numeric string corresponding to a port number. May * be an empty string, in which case all resolved endpoints will have a port * number of 0. * * @param resolve_flags A set of flags that determine how name resolution * should be performed. The default flags are suitable for communication with * remote hosts. See the @ref resolver_base documentation for the set of * available flags. * * @param token The @ref completion_token that will be used to produce a * completion handler, which will be called when the resolve completes. * Potential completion tokens include @ref use_future, @ref use_awaitable, * @ref yield_context, or a function object with the correct completion * signature. The function signature of the completion handler must be: * @code void handler( * const boost::system::error_code& error, // Result of operation. * resolver::results_type results // Resolved endpoints as a range. * ); @endcode * Regardless of whether the asynchronous operation completes immediately or * not, the completion handler will not be invoked from within this function. * On immediate completion, invocation of the handler will be performed in a * manner equivalent to using boost::asio::post(). * * A successful resolve operation is guaranteed to pass a non-empty range to * the handler. * * @par Completion Signature * @code void(boost::system::error_code, results_type) @endcode * * @note On POSIX systems, host names may be locally defined in the file * <tt>/etc/hosts</tt>. On Windows, host names may be defined in the file * <tt>c:\\windows\\system32\\drivers\\etc\\hosts</tt>. Remote host name * resolution is performed using DNS. Operating systems may use additional * locations when resolving host names (such as NETBIOS names on Windows). * * On POSIX systems, service names are typically defined in the file * <tt>/etc/services</tt>. On Windows, service names may be found in the file * <tt>c:\\windows\\system32\\drivers\\etc\\services</tt>. Operating systems * may use additional locations when resolving service names. */ template < BOOST_ASIO_COMPLETION_TOKEN_FOR(void (boost::system::error_code, results_type)) ResolveToken BOOST_ASIO_DEFAULT_COMPLETION_TOKEN_TYPE(executor_type)> BOOST_ASIO_INITFN_AUTO_RESULT_TYPE(ResolveToken, void (boost::system::error_code, results_type)) async_resolve(BOOST_ASIO_STRING_VIEW_PARAM host, BOOST_ASIO_STRING_VIEW_PARAM service, resolver_base::flags resolve_flags, BOOST_ASIO_MOVE_ARG(ResolveToken) token BOOST_ASIO_DEFAULT_COMPLETION_TOKEN(executor_type)) { basic_resolver_query<protocol_type> q(static_cast<std::string>(host), static_cast<std::string>(service), resolve_flags); return boost::asio::async_initiate<ResolveToken, void (boost::system::error_code, results_type)>( initiate_async_resolve(this), token, q); } /// Asynchronously perform forward resolution of a query to a list of entries. /** * This function is used to resolve host and service names into a list of * endpoint entries. It is an initiating function for an @ref * asynchronous_operation, and always returns immediately. * * @param protocol A protocol object, normally representing either the IPv4 or * IPv6 version of an internet protocol. * * @param host A string identifying a location. May be a descriptive name or * a numeric address string. If an empty string and the passive flag has been * specified, the resolved endpoints are suitable for local service binding. * If an empty string and passive is not specified, the resolved endpoints * will use the loopback address. * * @param service A string identifying the requested service. This may be a * descriptive name or a numeric string corresponding to a port number. May * be an empty string, in which case all resolved endpoints will have a port * number of 0. * * @param token The @ref completion_token that will be used to produce a * completion handler, which will be called when the resolve completes. * Potential completion tokens include @ref use_future, @ref use_awaitable, * @ref yield_context, or a function object with the correct completion * signature. The function signature of the completion handler must be: * @code void handler( * const boost::system::error_code& error, // Result of operation. * resolver::results_type results // Resolved endpoints as a range. * ); @endcode * Regardless of whether the asynchronous operation completes immediately or * not, the completion handler will not be invoked from within this function. * On immediate completion, invocation of the handler will be performed in a * manner equivalent to using boost::asio::post(). * * A successful resolve operation is guaranteed to pass a non-empty range to * the handler. * * @par Completion Signature * @code void(boost::system::error_code, results_type) @endcode * * @note On POSIX systems, host names may be locally defined in the file * <tt>/etc/hosts</tt>. On Windows, host names may be defined in the file * <tt>c:\\windows\\system32\\drivers\\etc\\hosts</tt>. Remote host name * resolution is performed using DNS. Operating systems may use additional * locations when resolving host names (such as NETBIOS names on Windows). * * On POSIX systems, service names are typically defined in the file * <tt>/etc/services</tt>. On Windows, service names may be found in the file * <tt>c:\\windows\\system32\\drivers\\etc\\services</tt>. Operating systems * may use additional locations when resolving service names. */ template < BOOST_ASIO_COMPLETION_TOKEN_FOR(void (boost::system::error_code, results_type)) ResolveToken BOOST_ASIO_DEFAULT_COMPLETION_TOKEN_TYPE(executor_type)> BOOST_ASIO_INITFN_AUTO_RESULT_TYPE(ResolveToken, void (boost::system::error_code, results_type)) async_resolve(const protocol_type& protocol, BOOST_ASIO_STRING_VIEW_PARAM host, BOOST_ASIO_STRING_VIEW_PARAM service, BOOST_ASIO_MOVE_ARG(ResolveToken) token BOOST_ASIO_DEFAULT_COMPLETION_TOKEN(executor_type)) { return async_resolve(protocol, host, service, resolver_base::flags(), BOOST_ASIO_MOVE_CAST(ResolveToken)(token)); } /// Asynchronously perform forward resolution of a query to a list of entries. /** * This function is used to resolve host and service names into a list of * endpoint entries. It is an initiating function for an @ref * asynchronous_operation, and always returns immediately. * * @param protocol A protocol object, normally representing either the IPv4 or * IPv6 version of an internet protocol. * * @param host A string identifying a location. May be a descriptive name or * a numeric address string. If an empty string and the passive flag has been * specified, the resolved endpoints are suitable for local service binding. * If an empty string and passive is not specified, the resolved endpoints * will use the loopback address. * * @param service A string identifying the requested service. This may be a * descriptive name or a numeric string corresponding to a port number. May * be an empty string, in which case all resolved endpoints will have a port * number of 0. * * @param resolve_flags A set of flags that determine how name resolution * should be performed. The default flags are suitable for communication with * remote hosts. See the @ref resolver_base documentation for the set of * available flags. * * @param token The @ref completion_token that will be used to produce a * completion handler, which will be called when the resolve completes. * Potential completion tokens include @ref use_future, @ref use_awaitable, * @ref yield_context, or a function object with the correct completion * signature. The function signature of the completion handler must be: * @code void handler( * const boost::system::error_code& error, // Result of operation. * resolver::results_type results // Resolved endpoints as a range. * ); @endcode * Regardless of whether the asynchronous operation completes immediately or * not, the completion handler will not be invoked from within this function. * On immediate completion, invocation of the handler will be performed in a * manner equivalent to using boost::asio::post(). * * A successful resolve operation is guaranteed to pass a non-empty range to * the handler. * * @par Completion Signature * @code void(boost::system::error_code, results_type) @endcode * * @note On POSIX systems, host names may be locally defined in the file * <tt>/etc/hosts</tt>. On Windows, host names may be defined in the file * <tt>c:\\windows\\system32\\drivers\\etc\\hosts</tt>. Remote host name * resolution is performed using DNS. Operating systems may use additional * locations when resolving host names (such as NETBIOS names on Windows). * * On POSIX systems, service names are typically defined in the file * <tt>/etc/services</tt>. On Windows, service names may be found in the file * <tt>c:\\windows\\system32\\drivers\\etc\\services</tt>. Operating systems * may use additional locations when resolving service names. */ template < BOOST_ASIO_COMPLETION_TOKEN_FOR(void (boost::system::error_code, results_type)) ResolveToken BOOST_ASIO_DEFAULT_COMPLETION_TOKEN_TYPE(executor_type)> BOOST_ASIO_INITFN_AUTO_RESULT_TYPE(ResolveToken, void (boost::system::error_code, results_type)) async_resolve(const protocol_type& protocol, BOOST_ASIO_STRING_VIEW_PARAM host, BOOST_ASIO_STRING_VIEW_PARAM service, resolver_base::flags resolve_flags, BOOST_ASIO_MOVE_ARG(ResolveToken) token BOOST_ASIO_DEFAULT_COMPLETION_TOKEN(executor_type)) { basic_resolver_query<protocol_type> q( protocol, static_cast<std::string>(host), static_cast<std::string>(service), resolve_flags); return boost::asio::async_initiate<ResolveToken, void (boost::system::error_code, results_type)>( initiate_async_resolve(this), token, q); } /// Perform reverse resolution of an endpoint to a list of entries. /** * This function is used to resolve an endpoint into a list of endpoint * entries. * * @param e An endpoint object that determines what endpoints will be * returned. * * @returns A range object representing the list of endpoint entries. A * successful call to this function is guaranteed to return a non-empty * range. * * @throws boost::system::system_error Thrown on failure. */ results_type resolve(const endpoint_type& e) { boost::system::error_code ec; results_type i = impl_.get_service().resolve( impl_.get_implementation(), e, ec); boost::asio::detail::throw_error(ec, "resolve"); return i; } /// Perform reverse resolution of an endpoint to a list of entries. /** * This function is used to resolve an endpoint into a list of endpoint * entries. * * @param e An endpoint object that determines what endpoints will be * returned. * * @param ec Set to indicate what error occurred, if any. * * @returns A range object representing the list of endpoint entries. An * empty range is returned if an error occurs. A successful call to this * function is guaranteed to return a non-empty range. */ results_type resolve(const endpoint_type& e, boost::system::error_code& ec) { return impl_.get_service().resolve(impl_.get_implementation(), e, ec); } /// Asynchronously perform reverse resolution of an endpoint to a list of /// entries. /** * This function is used to asynchronously resolve an endpoint into a list of * endpoint entries. It is an initiating function for an @ref * asynchronous_operation, and always returns immediately. * * @param e An endpoint object that determines what endpoints will be * returned. * * @param token The @ref completion_token that will be used to produce a * completion handler, which will be called when the resolve completes. * Potential completion tokens include @ref use_future, @ref use_awaitable, * @ref yield_context, or a function object with the correct completion * signature. The function signature of the completion handler must be: * @code void handler( * const boost::system::error_code& error, // Result of operation. * resolver::results_type results // Resolved endpoints as a range. * ); @endcode * Regardless of whether the asynchronous operation completes immediately or * not, the completion handler will not be invoked from within this function. * On immediate completion, invocation of the handler will be performed in a * manner equivalent to using boost::asio::post(). * * A successful resolve operation is guaranteed to pass a non-empty range to * the handler. * * @par Completion Signature * @code void(boost::system::error_code, results_type) @endcode */ template < BOOST_ASIO_COMPLETION_TOKEN_FOR(void (boost::system::error_code, results_type)) ResolveToken BOOST_ASIO_DEFAULT_COMPLETION_TOKEN_TYPE(executor_type)> BOOST_ASIO_INITFN_AUTO_RESULT_TYPE(ResolveToken, void (boost::system::error_code, results_type)) async_resolve(const endpoint_type& e, BOOST_ASIO_MOVE_ARG(ResolveToken) token BOOST_ASIO_DEFAULT_COMPLETION_TOKEN(executor_type)) { return boost::asio::async_initiate<ResolveToken, void (boost::system::error_code, results_type)>( initiate_async_resolve(this), token, e); } private: // Disallow copying and assignment. basic_resolver(const basic_resolver&) BOOST_ASIO_DELETED; basic_resolver& operator=(const basic_resolver&) BOOST_ASIO_DELETED; class initiate_async_resolve { public: typedef Executor executor_type; explicit initiate_async_resolve(basic_resolver* self) : self_(self) { } executor_type get_executor() const BOOST_ASIO_NOEXCEPT { return self_->get_executor(); } template <typename ResolveHandler, typename Query> void operator()(BOOST_ASIO_MOVE_ARG(ResolveHandler) handler, const Query& q) const { // If you get an error on the following line it means that your handler // does not meet the documented type requirements for a ResolveHandler. BOOST_ASIO_RESOLVE_HANDLER_CHECK( ResolveHandler, handler, results_type) type_check; boost::asio::detail::non_const_lvalue<ResolveHandler> handler2(handler); self_->impl_.get_service().async_resolve( self_->impl_.get_implementation(), q, handler2.value, self_->impl_.get_executor()); } private: basic_resolver* self_; }; # if defined(BOOST_ASIO_WINDOWS_RUNTIME) boost::asio::detail::io_object_impl< boost::asio::detail::winrt_resolver_service<InternetProtocol>, Executor> impl_; # else boost::asio::detail::io_object_impl< boost::asio::detail::resolver_service<InternetProtocol>, Executor> impl_; # endif }; } // namespace ip } // namespace asio } // namespace boost #include <boost/asio/detail/pop_options.hpp> #endif // BOOST_ASIO_IP_BASIC_RESOLVER_HPP