Insane_DNS/libraries/asio-1.28.1/include/asio/posix/basic_descriptor.hpp

782 lines
26 KiB
C++
Raw Permalink Normal View History

2023-10-24 21:59:30 -04:00
//
// posix/basic_descriptor.hpp
// ~~~~~~~~~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2023 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 ASIO_POSIX_BASIC_DESCRIPTOR_HPP
#define ASIO_POSIX_BASIC_DESCRIPTOR_HPP
#if defined(_MSC_VER) && (_MSC_VER >= 1200)
# pragma once
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
#include "asio/detail/config.hpp"
#if defined(ASIO_HAS_POSIX_STREAM_DESCRIPTOR) \
|| defined(GENERATING_DOCUMENTATION)
#include "asio/any_io_executor.hpp"
#include "asio/async_result.hpp"
#include "asio/detail/handler_type_requirements.hpp"
#include "asio/detail/io_object_impl.hpp"
#include "asio/detail/non_const_lvalue.hpp"
#include "asio/detail/throw_error.hpp"
#include "asio/error.hpp"
#include "asio/execution_context.hpp"
#include "asio/posix/descriptor_base.hpp"
#if defined(ASIO_HAS_IO_URING_AS_DEFAULT)
# include "asio/detail/io_uring_descriptor_service.hpp"
#else // defined(ASIO_HAS_IO_URING_AS_DEFAULT)
# include "asio/detail/reactive_descriptor_service.hpp"
#endif // defined(ASIO_HAS_IO_URING_AS_DEFAULT)
#if defined(ASIO_HAS_MOVE)
# include <utility>
#endif // defined(ASIO_HAS_MOVE)
#include "asio/detail/push_options.hpp"
namespace asio {
namespace posix {
/// Provides POSIX descriptor functionality.
/**
* The posix::basic_descriptor class template provides the ability to wrap a
* POSIX descriptor.
*
* @par Thread Safety
* @e Distinct @e objects: Safe.@n
* @e Shared @e objects: Unsafe.
*/
template <typename Executor = any_io_executor>
class basic_descriptor
: public descriptor_base
{
private:
class initiate_async_wait;
public:
/// The type of the executor associated with the object.
typedef Executor executor_type;
/// Rebinds the descriptor type to another executor.
template <typename Executor1>
struct rebind_executor
{
/// The descriptor type when rebound to the specified executor.
typedef basic_descriptor<Executor1> other;
};
/// The native representation of a descriptor.
#if defined(GENERATING_DOCUMENTATION)
typedef implementation_defined native_handle_type;
#elif defined(ASIO_HAS_IO_URING_AS_DEFAULT)
typedef detail::io_uring_descriptor_service::native_handle_type
native_handle_type;
#else // defined(ASIO_HAS_IO_URING_AS_DEFAULT)
typedef detail::reactive_descriptor_service::native_handle_type
native_handle_type;
#endif // defined(ASIO_HAS_IO_URING_AS_DEFAULT)
/// A descriptor is always the lowest layer.
typedef basic_descriptor lowest_layer_type;
/// Construct a descriptor without opening it.
/**
* This constructor creates a descriptor without opening it.
*
* @param ex The I/O executor that the descriptor will use, by default, to
* dispatch handlers for any asynchronous operations performed on the
* descriptor.
*/
explicit basic_descriptor(const executor_type& ex)
: impl_(0, ex)
{
}
/// Construct a descriptor without opening it.
/**
* This constructor creates a descriptor without opening it.
*
* @param context An execution context which provides the I/O executor that
* the descriptor will use, by default, to dispatch handlers for any
* asynchronous operations performed on the descriptor.
*/
template <typename ExecutionContext>
explicit basic_descriptor(ExecutionContext& context,
typename constraint<
is_convertible<ExecutionContext&, execution_context&>::value,
defaulted_constraint
>::type = defaulted_constraint())
: impl_(0, 0, context)
{
}
/// Construct a descriptor on an existing native descriptor.
/**
* This constructor creates a descriptor object to hold an existing native
* descriptor.
*
* @param ex The I/O executor that the descriptor will use, by default, to
* dispatch handlers for any asynchronous operations performed on the
* descriptor.
*
* @param native_descriptor A native descriptor.
*
* @throws asio::system_error Thrown on failure.
*/
basic_descriptor(const executor_type& ex,
const native_handle_type& native_descriptor)
: impl_(0, ex)
{
asio::error_code ec;
impl_.get_service().assign(impl_.get_implementation(),
native_descriptor, ec);
asio::detail::throw_error(ec, "assign");
}
/// Construct a descriptor on an existing native descriptor.
/**
* This constructor creates a descriptor object to hold an existing native
* descriptor.
*
* @param context An execution context which provides the I/O executor that
* the descriptor will use, by default, to dispatch handlers for any
* asynchronous operations performed on the descriptor.
*
* @param native_descriptor A native descriptor.
*
* @throws asio::system_error Thrown on failure.
*/
template <typename ExecutionContext>
basic_descriptor(ExecutionContext& context,
const native_handle_type& native_descriptor,
typename constraint<
is_convertible<ExecutionContext&, execution_context&>::value
>::type = 0)
: impl_(0, 0, context)
{
asio::error_code ec;
impl_.get_service().assign(impl_.get_implementation(),
native_descriptor, ec);
asio::detail::throw_error(ec, "assign");
}
#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
/// Move-construct a descriptor from another.
/**
* This constructor moves a descriptor from one object to another.
*
* @param other The other descriptor 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_descriptor(const executor_type&)
* constructor.
*/
basic_descriptor(basic_descriptor&& other) ASIO_NOEXCEPT
: impl_(std::move(other.impl_))
{
}
/// Move-assign a descriptor from another.
/**
* This assignment operator moves a descriptor from one object to another.
*
* @param other The other descriptor 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_descriptor(const executor_type&)
* constructor.
*/
basic_descriptor& operator=(basic_descriptor&& other)
{
impl_ = std::move(other.impl_);
return *this;
}
// All descriptors have access to each other's implementations.
template <typename Executor1>
friend class basic_descriptor;
/// Move-construct a basic_descriptor from a descriptor of another executor
/// type.
/**
* This constructor moves a descriptor from one object to another.
*
* @param other The other basic_descriptor 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_descriptor(const executor_type&)
* constructor.
*/
template <typename Executor1>
basic_descriptor(basic_descriptor<Executor1>&& other,
typename constraint<
is_convertible<Executor1, Executor>::value,
defaulted_constraint
>::type = defaulted_constraint())
: impl_(std::move(other.impl_))
{
}
/// Move-assign a basic_descriptor from a descriptor of another executor type.
/**
* This assignment operator moves a descriptor from one object to another.
*
* @param other The other basic_descriptor 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_descriptor(const executor_type&)
* constructor.
*/
template <typename Executor1>
typename constraint<
is_convertible<Executor1, Executor>::value,
basic_descriptor&
>::type operator=(basic_descriptor<Executor1> && other)
{
basic_descriptor tmp(std::move(other));
impl_ = std::move(tmp.impl_);
return *this;
}
#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
/// Get the executor associated with the object.
const executor_type& get_executor() ASIO_NOEXCEPT
{
return impl_.get_executor();
}
/// Get a reference to the lowest layer.
/**
* This function returns a reference to the lowest layer in a stack of
* layers. Since a descriptor cannot contain any further layers, it
* simply returns a reference to itself.
*
* @return A reference to the lowest layer in the stack of layers. Ownership
* is not transferred to the caller.
*/
lowest_layer_type& lowest_layer()
{
return *this;
}
/// Get a const reference to the lowest layer.
/**
* This function returns a const reference to the lowest layer in a stack of
* layers. Since a descriptor cannot contain any further layers, it
* simply returns a reference to itself.
*
* @return A const reference to the lowest layer in the stack of layers.
* Ownership is not transferred to the caller.
*/
const lowest_layer_type& lowest_layer() const
{
return *this;
}
/// Assign an existing native descriptor to the descriptor.
/*
* This function opens the descriptor to hold an existing native descriptor.
*
* @param native_descriptor A native descriptor.
*
* @throws asio::system_error Thrown on failure.
*/
void assign(const native_handle_type& native_descriptor)
{
asio::error_code ec;
impl_.get_service().assign(impl_.get_implementation(),
native_descriptor, ec);
asio::detail::throw_error(ec, "assign");
}
/// Assign an existing native descriptor to the descriptor.
/*
* This function opens the descriptor to hold an existing native descriptor.
*
* @param native_descriptor A native descriptor.
*
* @param ec Set to indicate what error occurred, if any.
*/
ASIO_SYNC_OP_VOID assign(const native_handle_type& native_descriptor,
asio::error_code& ec)
{
impl_.get_service().assign(
impl_.get_implementation(), native_descriptor, ec);
ASIO_SYNC_OP_VOID_RETURN(ec);
}
/// Determine whether the descriptor is open.
bool is_open() const
{
return impl_.get_service().is_open(impl_.get_implementation());
}
/// Close the descriptor.
/**
* This function is used to close the descriptor. Any asynchronous read or
* write operations will be cancelled immediately, and will complete with the
* asio::error::operation_aborted error.
*
* @throws asio::system_error Thrown on failure. Note that, even if
* the function indicates an error, the underlying descriptor is closed.
*/
void close()
{
asio::error_code ec;
impl_.get_service().close(impl_.get_implementation(), ec);
asio::detail::throw_error(ec, "close");
}
/// Close the descriptor.
/**
* This function is used to close the descriptor. Any asynchronous read or
* write operations will be cancelled immediately, and will complete with the
* asio::error::operation_aborted error.
*
* @param ec Set to indicate what error occurred, if any. Note that, even if
* the function indicates an error, the underlying descriptor is closed.
*/
ASIO_SYNC_OP_VOID close(asio::error_code& ec)
{
impl_.get_service().close(impl_.get_implementation(), ec);
ASIO_SYNC_OP_VOID_RETURN(ec);
}
/// Get the native descriptor representation.
/**
* This function may be used to obtain the underlying representation of the
* descriptor. This is intended to allow access to native descriptor
* functionality that is not otherwise provided.
*/
native_handle_type native_handle()
{
return impl_.get_service().native_handle(impl_.get_implementation());
}
/// Release ownership of the native descriptor implementation.
/**
* This function may be used to obtain the underlying representation of the
* descriptor. After calling this function, @c is_open() returns false. The
* caller is responsible for closing the descriptor.
*
* All outstanding asynchronous read or write operations will finish
* immediately, and the handlers for cancelled operations will be passed the
* asio::error::operation_aborted error.
*/
native_handle_type release()
{
return impl_.get_service().release(impl_.get_implementation());
}
/// Cancel all asynchronous operations associated with the descriptor.
/**
* This function causes all outstanding asynchronous read or write operations
* to finish immediately, and the handlers for cancelled operations will be
* passed the asio::error::operation_aborted error.
*
* @throws asio::system_error Thrown on failure.
*/
void cancel()
{
asio::error_code ec;
impl_.get_service().cancel(impl_.get_implementation(), ec);
asio::detail::throw_error(ec, "cancel");
}
/// Cancel all asynchronous operations associated with the descriptor.
/**
* This function causes all outstanding asynchronous read or write operations
* to finish immediately, and the handlers for cancelled operations will be
* passed the asio::error::operation_aborted error.
*
* @param ec Set to indicate what error occurred, if any.
*/
ASIO_SYNC_OP_VOID cancel(asio::error_code& ec)
{
impl_.get_service().cancel(impl_.get_implementation(), ec);
ASIO_SYNC_OP_VOID_RETURN(ec);
}
/// Perform an IO control command on the descriptor.
/**
* This function is used to execute an IO control command on the descriptor.
*
* @param command The IO control command to be performed on the descriptor.
*
* @throws asio::system_error Thrown on failure.
*
* @sa IoControlCommand @n
* asio::posix::descriptor_base::bytes_readable @n
* asio::posix::descriptor_base::non_blocking_io
*
* @par Example
* Getting the number of bytes ready to read:
* @code
* asio::posix::stream_descriptor descriptor(my_context);
* ...
* asio::posix::stream_descriptor::bytes_readable command;
* descriptor.io_control(command);
* std::size_t bytes_readable = command.get();
* @endcode
*/
template <typename IoControlCommand>
void io_control(IoControlCommand& command)
{
asio::error_code ec;
impl_.get_service().io_control(impl_.get_implementation(), command, ec);
asio::detail::throw_error(ec, "io_control");
}
/// Perform an IO control command on the descriptor.
/**
* This function is used to execute an IO control command on the descriptor.
*
* @param command The IO control command to be performed on the descriptor.
*
* @param ec Set to indicate what error occurred, if any.
*
* @sa IoControlCommand @n
* asio::posix::descriptor_base::bytes_readable @n
* asio::posix::descriptor_base::non_blocking_io
*
* @par Example
* Getting the number of bytes ready to read:
* @code
* asio::posix::stream_descriptor descriptor(my_context);
* ...
* asio::posix::stream_descriptor::bytes_readable command;
* asio::error_code ec;
* descriptor.io_control(command, ec);
* if (ec)
* {
* // An error occurred.
* }
* std::size_t bytes_readable = command.get();
* @endcode
*/
template <typename IoControlCommand>
ASIO_SYNC_OP_VOID io_control(IoControlCommand& command,
asio::error_code& ec)
{
impl_.get_service().io_control(impl_.get_implementation(), command, ec);
ASIO_SYNC_OP_VOID_RETURN(ec);
}
/// Gets the non-blocking mode of the descriptor.
/**
* @returns @c true if the descriptor's synchronous operations will fail with
* asio::error::would_block if they are unable to perform the requested
* operation immediately. If @c false, synchronous operations will block
* until complete.
*
* @note The non-blocking mode has no effect on the behaviour of asynchronous
* operations. Asynchronous operations will never fail with the error
* asio::error::would_block.
*/
bool non_blocking() const
{
return impl_.get_service().non_blocking(impl_.get_implementation());
}
/// Sets the non-blocking mode of the descriptor.
/**
* @param mode If @c true, the descriptor's synchronous operations will fail
* with asio::error::would_block if they are unable to perform the
* requested operation immediately. If @c false, synchronous operations will
* block until complete.
*
* @throws asio::system_error Thrown on failure.
*
* @note The non-blocking mode has no effect on the behaviour of asynchronous
* operations. Asynchronous operations will never fail with the error
* asio::error::would_block.
*/
void non_blocking(bool mode)
{
asio::error_code ec;
impl_.get_service().non_blocking(impl_.get_implementation(), mode, ec);
asio::detail::throw_error(ec, "non_blocking");
}
/// Sets the non-blocking mode of the descriptor.
/**
* @param mode If @c true, the descriptor's synchronous operations will fail
* with asio::error::would_block if they are unable to perform the
* requested operation immediately. If @c false, synchronous operations will
* block until complete.
*
* @param ec Set to indicate what error occurred, if any.
*
* @note The non-blocking mode has no effect on the behaviour of asynchronous
* operations. Asynchronous operations will never fail with the error
* asio::error::would_block.
*/
ASIO_SYNC_OP_VOID non_blocking(
bool mode, asio::error_code& ec)
{
impl_.get_service().non_blocking(impl_.get_implementation(), mode, ec);
ASIO_SYNC_OP_VOID_RETURN(ec);
}
/// Gets the non-blocking mode of the native descriptor implementation.
/**
* This function is used to retrieve the non-blocking mode of the underlying
* native descriptor. This mode has no effect on the behaviour of the
* descriptor object's synchronous operations.
*
* @returns @c true if the underlying descriptor is in non-blocking mode and
* direct system calls may fail with asio::error::would_block (or the
* equivalent system error).
*
* @note The current non-blocking mode is cached by the descriptor object.
* Consequently, the return value may be incorrect if the non-blocking mode
* was set directly on the native descriptor.
*/
bool native_non_blocking() const
{
return impl_.get_service().native_non_blocking(
impl_.get_implementation());
}
/// Sets the non-blocking mode of the native descriptor implementation.
/**
* This function is used to modify the non-blocking mode of the underlying
* native descriptor. It has no effect on the behaviour of the descriptor
* object's synchronous operations.
*
* @param mode If @c true, the underlying descriptor is put into non-blocking
* mode and direct system calls may fail with asio::error::would_block
* (or the equivalent system error).
*
* @throws asio::system_error Thrown on failure. If the @c mode is
* @c false, but the current value of @c non_blocking() is @c true, this
* function fails with asio::error::invalid_argument, as the
* combination does not make sense.
*/
void native_non_blocking(bool mode)
{
asio::error_code ec;
impl_.get_service().native_non_blocking(
impl_.get_implementation(), mode, ec);
asio::detail::throw_error(ec, "native_non_blocking");
}
/// Sets the non-blocking mode of the native descriptor implementation.
/**
* This function is used to modify the non-blocking mode of the underlying
* native descriptor. It has no effect on the behaviour of the descriptor
* object's synchronous operations.
*
* @param mode If @c true, the underlying descriptor is put into non-blocking
* mode and direct system calls may fail with asio::error::would_block
* (or the equivalent system error).
*
* @param ec Set to indicate what error occurred, if any. If the @c mode is
* @c false, but the current value of @c non_blocking() is @c true, this
* function fails with asio::error::invalid_argument, as the
* combination does not make sense.
*/
ASIO_SYNC_OP_VOID native_non_blocking(
bool mode, asio::error_code& ec)
{
impl_.get_service().native_non_blocking(
impl_.get_implementation(), mode, ec);
ASIO_SYNC_OP_VOID_RETURN(ec);
}
/// Wait for the descriptor to become ready to read, ready to write, or to
/// have pending error conditions.
/**
* This function is used to perform a blocking wait for a descriptor to enter
* a ready to read, write or error condition state.
*
* @param w Specifies the desired descriptor state.
*
* @par Example
* Waiting for a descriptor to become readable.
* @code
* asio::posix::stream_descriptor descriptor(my_context);
* ...
* descriptor.wait(asio::posix::stream_descriptor::wait_read);
* @endcode
*/
void wait(wait_type w)
{
asio::error_code ec;
impl_.get_service().wait(impl_.get_implementation(), w, ec);
asio::detail::throw_error(ec, "wait");
}
/// Wait for the descriptor to become ready to read, ready to write, or to
/// have pending error conditions.
/**
* This function is used to perform a blocking wait for a descriptor to enter
* a ready to read, write or error condition state.
*
* @param w Specifies the desired descriptor state.
*
* @param ec Set to indicate what error occurred, if any.
*
* @par Example
* Waiting for a descriptor to become readable.
* @code
* asio::posix::stream_descriptor descriptor(my_context);
* ...
* asio::error_code ec;
* descriptor.wait(asio::posix::stream_descriptor::wait_read, ec);
* @endcode
*/
ASIO_SYNC_OP_VOID wait(wait_type w, asio::error_code& ec)
{
impl_.get_service().wait(impl_.get_implementation(), w, ec);
ASIO_SYNC_OP_VOID_RETURN(ec);
}
/// Asynchronously wait for the descriptor to become ready to read, ready to
/// write, or to have pending error conditions.
/**
* This function is used to perform an asynchronous wait for a descriptor to
* enter a ready to read, write or error condition state. It is an initiating
* function for an @ref asynchronous_operation, and always returns
* immediately.
*
* @param w Specifies the desired descriptor state.
*
* @param token The @ref completion_token that will be used to produce a
* completion handler, which will be called when the wait 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 asio::error_code& error // Result of operation.
* ); @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 asio::post().
*
* @par Completion Signature
* @code void(asio::error_code) @endcode
*
* @par Example
* @code
* void wait_handler(const asio::error_code& error)
* {
* if (!error)
* {
* // Wait succeeded.
* }
* }
*
* ...
*
* asio::posix::stream_descriptor descriptor(my_context);
* ...
* descriptor.async_wait(
* asio::posix::stream_descriptor::wait_read,
* wait_handler);
* @endcode
*
* @par Per-Operation Cancellation
* This asynchronous operation supports cancellation for the following
* asio::cancellation_type values:
*
* @li @c cancellation_type::terminal
*
* @li @c cancellation_type::partial
*
* @li @c cancellation_type::total
*/
template <
ASIO_COMPLETION_TOKEN_FOR(void (asio::error_code))
WaitToken ASIO_DEFAULT_COMPLETION_TOKEN_TYPE(executor_type)>
ASIO_INITFN_AUTO_RESULT_TYPE_PREFIX(WaitToken,
void (asio::error_code))
async_wait(wait_type w,
ASIO_MOVE_ARG(WaitToken) token
ASIO_DEFAULT_COMPLETION_TOKEN(executor_type))
ASIO_INITFN_AUTO_RESULT_TYPE_SUFFIX((
async_initiate<WaitToken, void (asio::error_code)>(
declval<initiate_async_wait>(), token, w)))
{
return async_initiate<WaitToken, void (asio::error_code)>(
initiate_async_wait(this), token, w);
}
protected:
/// Protected destructor to prevent deletion through this type.
/**
* This function destroys the descriptor, cancelling any outstanding
* asynchronous wait operations associated with the descriptor as if by
* calling @c cancel.
*/
~basic_descriptor()
{
}
#if defined(ASIO_HAS_IO_URING_AS_DEFAULT)
detail::io_object_impl<detail::io_uring_descriptor_service, Executor> impl_;
#else // defined(ASIO_HAS_IO_URING_AS_DEFAULT)
detail::io_object_impl<detail::reactive_descriptor_service, Executor> impl_;
#endif // defined(ASIO_HAS_IO_URING_AS_DEFAULT)
private:
// Disallow copying and assignment.
basic_descriptor(const basic_descriptor&) ASIO_DELETED;
basic_descriptor& operator=(const basic_descriptor&) ASIO_DELETED;
class initiate_async_wait
{
public:
typedef Executor executor_type;
explicit initiate_async_wait(basic_descriptor* self)
: self_(self)
{
}
const executor_type& get_executor() const ASIO_NOEXCEPT
{
return self_->get_executor();
}
template <typename WaitHandler>
void operator()(ASIO_MOVE_ARG(WaitHandler) handler, wait_type w) const
{
// If you get an error on the following line it means that your handler
// does not meet the documented type requirements for a WaitHandler.
ASIO_WAIT_HANDLER_CHECK(WaitHandler, handler) type_check;
detail::non_const_lvalue<WaitHandler> handler2(handler);
self_->impl_.get_service().async_wait(
self_->impl_.get_implementation(), w,
handler2.value, self_->impl_.get_executor());
}
private:
basic_descriptor* self_;
};
};
} // namespace posix
} // namespace asio
#include "asio/detail/pop_options.hpp"
#endif // defined(ASIO_HAS_POSIX_STREAM_DESCRIPTOR)
// || defined(GENERATING_DOCUMENTATION)
#endif // ASIO_POSIX_BASIC_DESCRIPTOR_HPP