boost/beast/core/impl/basic_stream.hpp
// // Copyright (c) 2016-2019 Vinnie Falco (vinnie dot falco at gmail 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) // // Official repository: https://github.com/boostorg/beast // #ifndef BOOST_BEAST_CORE_IMPL_BASIC_STREAM_HPP #define BOOST_BEAST_CORE_IMPL_BASIC_STREAM_HPP #include <boost/beast/core/async_base.hpp> #include <boost/beast/core/buffer_traits.hpp> #include <boost/beast/core/buffers_prefix.hpp> #include <boost/beast/websocket/teardown.hpp> #include <boost/asio/coroutine.hpp> #include <boost/assert.hpp> #include <boost/make_shared.hpp> #include <boost/core/exchange.hpp> #include <cstdlib> #include <type_traits> #include <utility> namespace boost { namespace beast { //------------------------------------------------------------------------------ template<class Protocol, class Executor, class RatePolicy> template<class... Args> basic_stream<Protocol, Executor, RatePolicy>:: impl_type:: impl_type(std::false_type, Args&&... args) : socket(std::forward<Args>(args)...) , read(ex()) , write(ex()) , timer(ex()) { reset(); } template<class Protocol, class Executor, class RatePolicy> template<class RatePolicy_, class... Args> basic_stream<Protocol, Executor, RatePolicy>:: impl_type:: impl_type(std::true_type, RatePolicy_&& policy, Args&&... args) : boost::empty_value<RatePolicy>( boost::empty_init_t{}, std::forward<RatePolicy_>(policy)) , socket(std::forward<Args>(args)...) , read(ex()) , write(ex()) , timer(ex()) { reset(); } template<class Protocol, class Executor, class RatePolicy> template<class Executor2> void basic_stream<Protocol, Executor, RatePolicy>:: impl_type:: on_timer(Executor2 const& ex2) { BOOST_ASSERT(waiting > 0); // the last waiter starts the new slice if(--waiting > 0) return; // update the expiration time BOOST_VERIFY(timer.expires_after( std::chrono::seconds(1)) == 0); rate_policy_access::on_timer(policy()); struct handler : boost::empty_value<Executor2> { boost::weak_ptr<impl_type> wp; using executor_type = Executor2; executor_type get_executor() const noexcept { return this->get(); } handler( Executor2 const& ex2, boost::shared_ptr<impl_type> const& sp) : boost::empty_value<Executor2>( boost::empty_init_t{}, ex2) , wp(sp) { } void operator()(error_code ec) { auto sp = wp.lock(); if(! sp) return; if(ec == net::error::operation_aborted) return; BOOST_ASSERT(! ec); if(ec) return; sp->on_timer(this->get()); } }; // wait on the timer again ++waiting; timer.async_wait(handler(ex2, this->shared_from_this())); } template<class Protocol, class Executor, class RatePolicy> void basic_stream<Protocol, Executor, RatePolicy>:: impl_type:: reset() { // If assert goes off, it means that there are // already read or write (or connect) operations // outstanding, so there is nothing to apply // the expiration time to! // BOOST_ASSERT(! read.pending || ! write.pending); if(! read.pending) BOOST_VERIFY( read.timer.expires_at(never()) == 0); if(! write.pending) BOOST_VERIFY( write.timer.expires_at(never()) == 0); } template<class Protocol, class Executor, class RatePolicy> void basic_stream<Protocol, Executor, RatePolicy>:: impl_type:: close() noexcept { { error_code ec; socket.close(ec); } try { timer.cancel(); } catch(...) { } } //------------------------------------------------------------------------------ template<class Protocol, class Executor, class RatePolicy> template<class Executor2> struct basic_stream<Protocol, Executor, RatePolicy>:: timeout_handler { using executor_type = Executor2; op_state& state; boost::weak_ptr<impl_type> wp; tick_type tick; executor_type ex; executor_type get_executor() const noexcept { return ex; } void operator()(error_code ec) { // timer canceled if(ec == net::error::operation_aborted) return; BOOST_ASSERT(! ec); auto sp = wp.lock(); // stream destroyed if(! sp) return; // stale timer if(tick < state.tick) return; BOOST_ASSERT(tick == state.tick); // timeout BOOST_ASSERT(! state.timeout); sp->close(); state.timeout = true; } }; //------------------------------------------------------------------------------ template<class Protocol, class Executor, class RatePolicy> struct basic_stream<Protocol, Executor, RatePolicy>::ops { template<bool isRead, class Buffers, class Handler> class transfer_op : public async_base<Handler, Executor> , public boost::asio::coroutine { boost::shared_ptr<impl_type> impl_; pending_guard pg_; Buffers b_; using is_read = std::integral_constant<bool, isRead>; op_state& state() { if (isRead) return impl_->read; else return impl_->write; } std::size_t available_bytes() { if (isRead) return rate_policy_access:: available_read_bytes(impl_->policy()); else return rate_policy_access:: available_write_bytes(impl_->policy()); } void transfer_bytes(std::size_t n) { if (isRead) rate_policy_access:: transfer_read_bytes(impl_->policy(), n); else rate_policy_access:: transfer_write_bytes(impl_->policy(), n); } void async_perform( std::size_t amount, std::true_type) { impl_->socket.async_read_some( beast::buffers_prefix(amount, b_), std::move(*this)); } void async_perform( std::size_t amount, std::false_type) { impl_->socket.async_write_some( beast::buffers_prefix(amount, b_), std::move(*this)); } static bool never_pending_; public: template<class Handler_> transfer_op( Handler_&& h, basic_stream& s, Buffers const& b) : async_base<Handler, Executor>( std::forward<Handler_>(h), s.get_executor()) , impl_(s.impl_) , pg_() , b_(b) { this->set_allowed_cancellation(net::cancellation_type::all); if (buffer_bytes(b_) == 0 && state().pending) { // Workaround: // Corner case discovered in https://github.com/boostorg/beast/issues/2065 // Enclosing SSL stream wishes to complete a 0-length write early by // executing a 0-length read against the underlying stream. // This can occur even if an existing async_read is in progress. // In this specific case, we will complete the async op with no error // in order to prevent assertions and/or internal corruption of the basic_stream this->complete(false, error_code(), 0); } else { pg_.assign(state().pending); (*this)({}); } } void operator()( error_code ec, std::size_t bytes_transferred = 0) { BOOST_ASIO_CORO_REENTER(*this) { // handle empty buffers if(detail::buffers_empty(b_)) { // make sure we perform the no-op BOOST_ASIO_CORO_YIELD { BOOST_ASIO_HANDLER_LOCATION(( __FILE__, __LINE__, (isRead ? "basic_stream::async_read_some" : "basic_stream::async_write_some"))); async_perform(0, is_read{}); } // apply the timeout manually, otherwise // behavior varies across platforms. if(state().timer.expiry() <= clock_type::now()) { impl_->close(); BOOST_BEAST_ASSIGN_EC(ec, beast::error::timeout); } goto upcall; } // if a timeout is active, wait on the timer if(state().timer.expiry() != never()) { BOOST_ASIO_HANDLER_LOCATION(( __FILE__, __LINE__, (isRead ? "basic_stream::async_read_some" : "basic_stream::async_write_some"))); state().timer.async_wait( timeout_handler<decltype(this->get_executor())>{ state(), impl_, state().tick, this->get_executor()}); } // check rate limit, maybe wait std::size_t amount; amount = available_bytes(); if(amount == 0) { ++impl_->waiting; BOOST_ASIO_CORO_YIELD { BOOST_ASIO_HANDLER_LOCATION(( __FILE__, __LINE__, (isRead ? "basic_stream::async_read_some" : "basic_stream::async_write_some"))); impl_->timer.async_wait(std::move(*this)); } if(ec) { // socket was closed, or a timeout BOOST_ASSERT(ec == net::error::operation_aborted); // timeout handler invoked? if(state().timeout) { // yes, socket already closed BOOST_BEAST_ASSIGN_EC(ec, beast::error::timeout); state().timeout = false; } goto upcall; } impl_->on_timer(this->get_executor()); // Allow at least one byte, otherwise // bytes_transferred could be 0. amount = std::max<std::size_t>( available_bytes(), 1); } BOOST_ASIO_CORO_YIELD { BOOST_ASIO_HANDLER_LOCATION(( __FILE__, __LINE__, (isRead ? "basic_stream::async_read_some" : "basic_stream::async_write_some"))); async_perform(amount, is_read{}); } if(state().timer.expiry() != never()) { ++state().tick; // try cancelling timer auto const n = state().timer.cancel(); if(n == 0) { // timeout handler invoked? if(state().timeout) { // yes, socket already closed BOOST_BEAST_ASSIGN_EC(ec, beast::error::timeout); state().timeout = false; } } else { BOOST_ASSERT(n == 1); BOOST_ASSERT(! state().timeout); } } upcall: pg_.reset(); transfer_bytes(bytes_transferred); this->complete_now(ec, bytes_transferred); } } }; template<class Handler> class connect_op : public async_base<Handler, Executor> { boost::shared_ptr<impl_type> impl_; pending_guard pg0_; pending_guard pg1_; op_state& state() noexcept { return impl_->write; } public: template<class Handler_> connect_op( Handler_&& h, basic_stream& s, endpoint_type ep) : async_base<Handler, Executor>( std::forward<Handler_>(h), s.get_executor()) , impl_(s.impl_) , pg0_(impl_->read.pending) , pg1_(impl_->write.pending) { this->set_allowed_cancellation(net::cancellation_type::all); if(state().timer.expiry() != stream_base::never()) { BOOST_ASIO_HANDLER_LOCATION(( __FILE__, __LINE__, "basic_stream::async_connect")); impl_->write.timer.async_wait( timeout_handler<decltype(this->get_executor())>{ state(), impl_, state().tick, this->get_executor()}); } BOOST_ASIO_HANDLER_LOCATION(( __FILE__, __LINE__, "basic_stream::async_connect")); impl_->socket.async_connect( ep, std::move(*this)); // *this is now moved-from } template< class Endpoints, class Condition, class Handler_> connect_op( Handler_&& h, basic_stream& s, Endpoints const& eps, Condition const& cond) : async_base<Handler, Executor>( std::forward<Handler_>(h), s.get_executor()) , impl_(s.impl_) , pg0_(impl_->read.pending) , pg1_(impl_->write.pending) { this->set_allowed_cancellation(net::cancellation_type::all); if(state().timer.expiry() != stream_base::never()) { BOOST_ASIO_HANDLER_LOCATION(( __FILE__, __LINE__, "basic_stream::async_connect")); impl_->write.timer.async_wait( timeout_handler<decltype(this->get_executor())>{ state(), impl_, state().tick, this->get_executor()}); } BOOST_ASIO_HANDLER_LOCATION(( __FILE__, __LINE__, "basic_stream::async_connect")); net::async_connect(impl_->socket, eps, cond, std::move(*this)); // *this is now moved-from } template< class Iterator, class Condition, class Handler_> connect_op( Handler_&& h, basic_stream& s, Iterator begin, Iterator end, Condition const& cond) : async_base<Handler, Executor>( std::forward<Handler_>(h), s.get_executor()) , impl_(s.impl_) , pg0_(impl_->read.pending) , pg1_(impl_->write.pending) { this->set_allowed_cancellation(net::cancellation_type::all); if(state().timer.expiry() != stream_base::never()) { BOOST_ASIO_HANDLER_LOCATION(( __FILE__, __LINE__, "basic_stream::async_connect")); impl_->write.timer.async_wait( timeout_handler<decltype(this->get_executor())>{ state(), impl_, state().tick, this->get_executor()}); } BOOST_ASIO_HANDLER_LOCATION(( __FILE__, __LINE__, "basic_stream::async_connect")); net::async_connect(impl_->socket, begin, end, cond, std::move(*this)); // *this is now moved-from } template<class... Args> void operator()(error_code ec, Args&&... args) { if(state().timer.expiry() != stream_base::never()) { ++state().tick; // try cancelling timer auto const n = impl_->write.timer.cancel(); if(n == 0) { // timeout handler invoked? if(state().timeout) { // yes, socket already closed BOOST_BEAST_ASSIGN_EC(ec, beast::error::timeout); state().timeout = false; } } else { BOOST_ASSERT(n == 1); BOOST_ASSERT(! state().timeout); } } pg0_.reset(); pg1_.reset(); this->complete_now(ec, std::forward<Args>(args)...); } }; struct run_read_op { template<class ReadHandler, class Buffers> void operator()( ReadHandler&& h, basic_stream* s, Buffers const& b) { // If you get an error on the following line it means // that your handler does not meet the documented type // requirements for the handler. static_assert( detail::is_invocable<ReadHandler, void(error_code, std::size_t)>::value, "ReadHandler type requirements not met"); transfer_op< true, Buffers, typename std::decay<ReadHandler>::type>( std::forward<ReadHandler>(h), *s, b); } }; struct run_write_op { template<class WriteHandler, class Buffers> void operator()( WriteHandler&& h, basic_stream* s, Buffers const& b) { // If you get an error on the following line it means // that your handler does not meet the documented type // requirements for the handler. static_assert( detail::is_invocable<WriteHandler, void(error_code, std::size_t)>::value, "WriteHandler type requirements not met"); transfer_op< false, Buffers, typename std::decay<WriteHandler>::type>( std::forward<WriteHandler>(h), *s, b); } }; struct run_connect_op { template<class ConnectHandler> void operator()( ConnectHandler&& h, basic_stream* s, endpoint_type const& ep) { // If you get an error on the following line it means // that your handler does not meet the documented type // requirements for the handler. static_assert( detail::is_invocable<ConnectHandler, void(error_code)>::value, "ConnectHandler type requirements not met"); connect_op<typename std::decay<ConnectHandler>::type>( std::forward<ConnectHandler>(h), *s, ep); } }; struct run_connect_range_op { template< class RangeConnectHandler, class EndpointSequence, class Condition> void operator()( RangeConnectHandler&& h, basic_stream* s, EndpointSequence const& eps, Condition const& cond) { // If you get an error on the following line it means // that your handler does not meet the documented type // requirements for the handler. static_assert( detail::is_invocable<RangeConnectHandler, void(error_code, typename Protocol::endpoint)>::value, "RangeConnectHandler type requirements not met"); connect_op<typename std::decay<RangeConnectHandler>::type>( std::forward<RangeConnectHandler>(h), *s, eps, cond); } }; struct run_connect_iter_op { template< class IteratorConnectHandler, class Iterator, class Condition> void operator()( IteratorConnectHandler&& h, basic_stream* s, Iterator begin, Iterator end, Condition const& cond) { // If you get an error on the following line it means // that your handler does not meet the documented type // requirements for the handler. static_assert( detail::is_invocable<IteratorConnectHandler, void(error_code, Iterator)>::value, "IteratorConnectHandler type requirements not met"); connect_op<typename std::decay<IteratorConnectHandler>::type>( std::forward<IteratorConnectHandler>(h), *s, begin, end, cond); } }; }; //------------------------------------------------------------------------------ template<class Protocol, class Executor, class RatePolicy> basic_stream<Protocol, Executor, RatePolicy>:: ~basic_stream() { // the shared object can outlive *this, // cancel any operations so the shared // object is destroyed as soon as possible. impl_->close(); } template<class Protocol, class Executor, class RatePolicy> template<class Arg0, class... Args, class> basic_stream<Protocol, Executor, RatePolicy>:: basic_stream(Arg0&& arg0, Args&&... args) : impl_(boost::make_shared<impl_type>( std::false_type{}, std::forward<Arg0>(arg0), std::forward<Args>(args)...)) { } template<class Protocol, class Executor, class RatePolicy> template<class RatePolicy_, class Arg0, class... Args, class> basic_stream<Protocol, Executor, RatePolicy>:: basic_stream( RatePolicy_&& policy, Arg0&& arg0, Args&&... args) : impl_(boost::make_shared<impl_type>( std::true_type{}, std::forward<RatePolicy_>(policy), std::forward<Arg0>(arg0), std::forward<Args>(args)...)) { } template<class Protocol, class Executor, class RatePolicy> basic_stream<Protocol, Executor, RatePolicy>:: basic_stream(basic_stream&& other) : impl_(boost::make_shared<impl_type>( std::move(*other.impl_))) { // Explainer: Asio's sockets provide the guarantee that a moved-from socket // will be in a state as-if newly created. i.e.: // * having the same (valid) executor // * the socket shall not be open // We provide the same guarantee by moving the impl rather than the pointer // controlling its lifetime. } template<class Protocol, class Executor, class RatePolicy> template<class Executor_> basic_stream<Protocol, Executor, RatePolicy>:: basic_stream(basic_stream<Protocol, Executor_, RatePolicy> && other) : impl_(boost::make_shared<impl_type>(std::false_type{}, std::move(other.impl_->socket))) { } //------------------------------------------------------------------------------ template<class Protocol, class Executor, class RatePolicy> auto basic_stream<Protocol, Executor, RatePolicy>:: release_socket() -> socket_type { this->cancel(); return std::move(impl_->socket); } template<class Protocol, class Executor, class RatePolicy> void basic_stream<Protocol, Executor, RatePolicy>:: expires_after(net::steady_timer::duration expiry_time) { // If assert goes off, it means that there are // already read or write (or connect) operations // outstanding, so there is nothing to apply // the expiration time to! // BOOST_ASSERT( ! impl_->read.pending || ! impl_->write.pending); if(! impl_->read.pending) BOOST_VERIFY( impl_->read.timer.expires_after( expiry_time) == 0); if(! impl_->write.pending) BOOST_VERIFY( impl_->write.timer.expires_after( expiry_time) == 0); } template<class Protocol, class Executor, class RatePolicy> void basic_stream<Protocol, Executor, RatePolicy>:: expires_at( net::steady_timer::time_point expiry_time) { // If assert goes off, it means that there are // already read or write (or connect) operations // outstanding, so there is nothing to apply // the expiration time to! // BOOST_ASSERT( ! impl_->read.pending || ! impl_->write.pending); if(! impl_->read.pending) BOOST_VERIFY( impl_->read.timer.expires_at( expiry_time) == 0); if(! impl_->write.pending) BOOST_VERIFY( impl_->write.timer.expires_at( expiry_time) == 0); } template<class Protocol, class Executor, class RatePolicy> void basic_stream<Protocol, Executor, RatePolicy>:: expires_never() { impl_->reset(); } template<class Protocol, class Executor, class RatePolicy> void basic_stream<Protocol, Executor, RatePolicy>:: cancel() { error_code ec; impl_->socket.cancel(ec); impl_->timer.cancel(); } template<class Protocol, class Executor, class RatePolicy> void basic_stream<Protocol, Executor, RatePolicy>:: close() { impl_->close(); } //------------------------------------------------------------------------------ template<class Protocol, class Executor, class RatePolicy> template<BOOST_BEAST_ASYNC_TPARAM1 ConnectHandler> BOOST_BEAST_ASYNC_RESULT1(ConnectHandler) basic_stream<Protocol, Executor, RatePolicy>:: async_connect( endpoint_type const& ep, ConnectHandler&& handler) { return net::async_initiate< ConnectHandler, void(error_code)>( typename ops::run_connect_op{}, handler, this, ep); } template<class Protocol, class Executor, class RatePolicy> template< class EndpointSequence, BOOST_ASIO_COMPLETION_TOKEN_FOR(void(error_code, typename Protocol::endpoint)) RangeConnectHandler, class> BOOST_ASIO_INITFN_RESULT_TYPE(RangeConnectHandler,void(error_code, typename Protocol::endpoint)) basic_stream<Protocol, Executor, RatePolicy>:: async_connect( EndpointSequence const& endpoints, RangeConnectHandler&& handler) { return net::async_initiate< RangeConnectHandler, void(error_code, typename Protocol::endpoint)>( typename ops::run_connect_range_op{}, handler, this, endpoints, detail::any_endpoint{}); } template<class Protocol, class Executor, class RatePolicy> template< class EndpointSequence, class ConnectCondition, BOOST_ASIO_COMPLETION_TOKEN_FOR(void(error_code, typename Protocol::endpoint)) RangeConnectHandler, class> BOOST_ASIO_INITFN_RESULT_TYPE(RangeConnectHandler,void (error_code, typename Protocol::endpoint)) basic_stream<Protocol, Executor, RatePolicy>:: async_connect( EndpointSequence const& endpoints, ConnectCondition connect_condition, RangeConnectHandler&& handler) { return net::async_initiate< RangeConnectHandler, void(error_code, typename Protocol::endpoint)>( typename ops::run_connect_range_op{}, handler, this, endpoints, connect_condition); } template<class Protocol, class Executor, class RatePolicy> template< class Iterator, BOOST_ASIO_COMPLETION_TOKEN_FOR(void(error_code, Iterator)) IteratorConnectHandler> BOOST_ASIO_INITFN_RESULT_TYPE(IteratorConnectHandler,void (error_code, Iterator)) basic_stream<Protocol, Executor, RatePolicy>:: async_connect( Iterator begin, Iterator end, IteratorConnectHandler&& handler) { return net::async_initiate< IteratorConnectHandler, void(error_code, Iterator)>( typename ops::run_connect_iter_op{}, handler, this, begin, end, detail::any_endpoint{}); } template<class Protocol, class Executor, class RatePolicy> template< class Iterator, class ConnectCondition, BOOST_ASIO_COMPLETION_TOKEN_FOR(void(error_code, Iterator)) IteratorConnectHandler> BOOST_ASIO_INITFN_RESULT_TYPE(IteratorConnectHandler,void (error_code, Iterator)) basic_stream<Protocol, Executor, RatePolicy>:: async_connect( Iterator begin, Iterator end, ConnectCondition connect_condition, IteratorConnectHandler&& handler) { return net::async_initiate< IteratorConnectHandler, void(error_code, Iterator)>( typename ops::run_connect_iter_op{}, handler, this, begin, end, connect_condition); } //------------------------------------------------------------------------------ template<class Protocol, class Executor, class RatePolicy> template<class MutableBufferSequence, BOOST_BEAST_ASYNC_TPARAM2 ReadHandler> BOOST_BEAST_ASYNC_RESULT2(ReadHandler) basic_stream<Protocol, Executor, RatePolicy>:: async_read_some( MutableBufferSequence const& buffers, ReadHandler&& handler) { static_assert(net::is_mutable_buffer_sequence< MutableBufferSequence>::value, "MutableBufferSequence type requirements not met"); return net::async_initiate< ReadHandler, void(error_code, std::size_t)>( typename ops::run_read_op{}, handler, this, buffers); } template<class Protocol, class Executor, class RatePolicy> template<class ConstBufferSequence, BOOST_BEAST_ASYNC_TPARAM2 WriteHandler> BOOST_BEAST_ASYNC_RESULT2(WriteHandler) basic_stream<Protocol, Executor, RatePolicy>:: async_write_some( ConstBufferSequence const& buffers, WriteHandler&& handler) { static_assert(net::is_const_buffer_sequence< ConstBufferSequence>::value, "ConstBufferSequence type requirements not met"); return net::async_initiate< WriteHandler, void(error_code, std::size_t)>( typename ops::run_write_op{}, handler, this, buffers); } //------------------------------------------------------------------------------ // // Customization points // #if ! BOOST_BEAST_DOXYGEN template< class Protocol, class Executor, class RatePolicy> void beast_close_socket( basic_stream<Protocol, Executor, RatePolicy>& stream) { error_code ec; stream.socket().close(ec); } template< class Protocol, class Executor, class RatePolicy> void teardown( role_type role, basic_stream<Protocol, Executor, RatePolicy>& stream, error_code& ec) { using beast::websocket::teardown; teardown(role, stream.socket(), ec); } template< class Protocol, class Executor, class RatePolicy, class TeardownHandler> void async_teardown( role_type role, basic_stream<Protocol, Executor, RatePolicy>& stream, TeardownHandler&& handler) { using beast::websocket::async_teardown; async_teardown(role, stream.socket(), std::forward<TeardownHandler>(handler)); } #endif } // beast } // boost #endif