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//
// windows/random_access_handle.hpp
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2017 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_WINDOWS_RANDOM_ACCESS_HANDLE_HPP
#define ASIO_WINDOWS_RANDOM_ACCESS_HANDLE_HPP
#if defined(_MSC_VER) && (_MSC_VER >= 1200)
# pragma once
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
#include "asio/detail/config.hpp"
#include "asio/windows/overlapped_handle.hpp"
#if defined(ASIO_HAS_WINDOWS_RANDOM_ACCESS_HANDLE) \
|| defined(GENERATING_DOCUMENTATION)
#if defined(ASIO_ENABLE_OLD_SERVICES)
# include "asio/windows/basic_random_access_handle.hpp"
#endif // defined(ASIO_ENABLE_OLD_SERVICES)
#include "asio/detail/push_options.hpp"
namespace asio {
namespace windows {
#if defined(ASIO_ENABLE_OLD_SERVICES)
// Typedef for the typical usage of a random-access handle.
typedef basic_random_access_handle<> random_access_handle;
#else // defined(ASIO_ENABLE_OLD_SERVICES)
/// Provides random-access handle functionality.
/**
* The windows::random_access_handle class provides asynchronous and
* blocking random-access handle functionality.
*
* @par Thread Safety
* @e Distinct @e objects: Safe.@n
* @e Shared @e objects: Unsafe.
*/
class random_access_handle
: public overlapped_handle
{
public:
/// Construct a random_access_handle without opening it.
/**
* This constructor creates a random-access handle without opening it. The
* handle needs to be opened before data can be written to or read from it.
*
* @param io_context The io_context object that the random-access handle will
* use to dispatch handlers for any asynchronous operations performed on the
* handle.
*/
explicit random_access_handle(asio::io_context& io_context)
: overlapped_handle(io_context)
{
}
/// Construct a random_access_handle on an existing native handle.
/**
* This constructor creates a random-access handle object to hold an existing
* native handle.
*
* @param io_context The io_context object that the random-access handle will
* use to dispatch handlers for any asynchronous operations performed on the
* handle.
*
* @param handle The new underlying handle implementation.
*
* @throws asio::system_error Thrown on failure.
*/
random_access_handle(asio::io_context& io_context,
const native_handle_type& handle)
: overlapped_handle(io_context, handle)
{
}
#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
/// Move-construct a random_access_handle from another.
/**
* This constructor moves a random-access handle from one object to another.
*
* @param other The other random_access_handle 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 random_access_handle(io_context&)
* constructor.
*/
random_access_handle(random_access_handle&& other)
: overlapped_handle(std::move(other))
{
}
/// Move-assign a random_access_handle from another.
/**
* This assignment operator moves a random-access handle from one object to
* another.
*
* @param other The other random_access_handle 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 random_access_handle(io_context&)
* constructor.
*/
random_access_handle& operator=(random_access_handle&& other)
{
overlapped_handle::operator=(std::move(other));
return *this;
}
#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
/// Write some data to the handle at the specified offset.
/**
* This function is used to write data to the random-access handle. The
* function call will block until one or more bytes of the data has been
* written successfully, or until an error occurs.
*
* @param offset The offset at which the data will be written.
*
* @param buffers One or more data buffers to be written to the handle.
*
* @returns The number of bytes written.
*
* @throws asio::system_error Thrown on failure. An error code of
* asio::error::eof indicates that the connection was closed by the
* peer.
*
* @note The write_some_at operation may not write all of the data. Consider
* using the @ref write_at function if you need to ensure that all data is
* written before the blocking operation completes.
*
* @par Example
* To write a single data buffer use the @ref buffer function as follows:
* @code
* handle.write_some_at(42, asio::buffer(data, size));
* @endcode
* See the @ref buffer documentation for information on writing multiple
* buffers in one go, and how to use it with arrays, boost::array or
* std::vector.
*/
template <typename ConstBufferSequence>
std::size_t write_some_at(uint64_t offset,
const ConstBufferSequence& buffers)
{
asio::error_code ec;
std::size_t s = this->get_service().write_some_at(
this->get_implementation(), offset, buffers, ec);
asio::detail::throw_error(ec, "write_some_at");
return s;
}
/// Write some data to the handle at the specified offset.
/**
* This function is used to write data to the random-access handle. The
* function call will block until one or more bytes of the data has been
* written successfully, or until an error occurs.
*
* @param offset The offset at which the data will be written.
*
* @param buffers One or more data buffers to be written to the handle.
*
* @param ec Set to indicate what error occurred, if any.
*
* @returns The number of bytes written. Returns 0 if an error occurred.
*
* @note The write_some operation may not transmit all of the data to the
* peer. Consider using the @ref write_at function if you need to ensure that
* all data is written before the blocking operation completes.
*/
template <typename ConstBufferSequence>
std::size_t write_some_at(uint64_t offset,
const ConstBufferSequence& buffers, asio::error_code& ec)
{
return this->get_service().write_some_at(
this->get_implementation(), offset, buffers, ec);
}
/// Start an asynchronous write at the specified offset.
/**
* This function is used to asynchronously write data to the random-access
* handle. The function call always returns immediately.
*
* @param offset The offset at which the data will be written.
*
* @param buffers One or more data buffers to be written to the handle.
* Although the buffers object may be copied as necessary, ownership of the
* underlying memory blocks is retained by the caller, which must guarantee
* that they remain valid until the handler is called.
*
* @param handler The handler to be called when the write operation completes.
* Copies will be made of the handler as required. The function signature of
* the handler must be:
* @code void handler(
* const asio::error_code& error, // Result of operation.
* std::size_t bytes_transferred // Number of bytes written.
* ); @endcode
* Regardless of whether the asynchronous operation completes immediately or
* not, the handler will not be invoked from within this function. Invocation
* of the handler will be performed in a manner equivalent to using
* asio::io_context::post().
*
* @note The write operation may not transmit all of the data to the peer.
* Consider using the @ref async_write_at function if you need to ensure that
* all data is written before the asynchronous operation completes.
*
* @par Example
* To write a single data buffer use the @ref buffer function as follows:
* @code
* handle.async_write_some_at(42, asio::buffer(data, size), handler);
* @endcode
* See the @ref buffer documentation for information on writing multiple
* buffers in one go, and how to use it with arrays, boost::array or
* std::vector.
*/
template <typename ConstBufferSequence, typename WriteHandler>
ASIO_INITFN_RESULT_TYPE(WriteHandler,
void (asio::error_code, std::size_t))
async_write_some_at(uint64_t offset,
const ConstBufferSequence& buffers,
ASIO_MOVE_ARG(WriteHandler) handler)
{
// If you get an error on the following line it means that your handler does
// not meet the documented type requirements for a WriteHandler.
ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check;
asio::async_completion<WriteHandler,
void (asio::error_code, std::size_t)> init(handler);
this->get_service().async_write_some_at(this->get_implementation(),
offset, buffers, init.completion_handler);
return init.result.get();
}
/// Read some data from the handle at the specified offset.
/**
* This function is used to read data from the random-access handle. The
* function call will block until one or more bytes of data has been read
* successfully, or until an error occurs.
*
* @param offset The offset at which the data will be read.
*
* @param buffers One or more buffers into which the data will be read.
*
* @returns The number of bytes read.
*
* @throws asio::system_error Thrown on failure. An error code of
* asio::error::eof indicates that the connection was closed by the
* peer.
*
* @note The read_some operation may not read all of the requested number of
* bytes. Consider using the @ref read_at function if you need to ensure that
* the requested amount of data is read before the blocking operation
* completes.
*
* @par Example
* To read into a single data buffer use the @ref buffer function as follows:
* @code
* handle.read_some_at(42, asio::buffer(data, size));
* @endcode
* See the @ref buffer documentation for information on reading into multiple
* buffers in one go, and how to use it with arrays, boost::array or
* std::vector.
*/
template <typename MutableBufferSequence>
std::size_t read_some_at(uint64_t offset,
const MutableBufferSequence& buffers)
{
asio::error_code ec;
std::size_t s = this->get_service().read_some_at(
this->get_implementation(), offset, buffers, ec);
asio::detail::throw_error(ec, "read_some_at");
return s;
}
/// Read some data from the handle at the specified offset.
/**
* This function is used to read data from the random-access handle. The
* function call will block until one or more bytes of data has been read
* successfully, or until an error occurs.
*
* @param offset The offset at which the data will be read.
*
* @param buffers One or more buffers into which the data will be read.
*
* @param ec Set to indicate what error occurred, if any.
*
* @returns The number of bytes read. Returns 0 if an error occurred.
*
* @note The read_some operation may not read all of the requested number of
* bytes. Consider using the @ref read_at function if you need to ensure that
* the requested amount of data is read before the blocking operation
* completes.
*/
template <typename MutableBufferSequence>
std::size_t read_some_at(uint64_t offset,
const MutableBufferSequence& buffers, asio::error_code& ec)
{
return this->get_service().read_some_at(
this->get_implementation(), offset, buffers, ec);
}
/// Start an asynchronous read at the specified offset.
/**
* This function is used to asynchronously read data from the random-access
* handle. The function call always returns immediately.
*
* @param offset The offset at which the data will be read.
*
* @param buffers One or more buffers into which the data will be read.
* Although the buffers object may be copied as necessary, ownership of the
* underlying memory blocks is retained by the caller, which must guarantee
* that they remain valid until the handler is called.
*
* @param handler The handler to be called when the read operation completes.
* Copies will be made of the handler as required. The function signature of
* the handler must be:
* @code void handler(
* const asio::error_code& error, // Result of operation.
* std::size_t bytes_transferred // Number of bytes read.
* ); @endcode
* Regardless of whether the asynchronous operation completes immediately or
* not, the handler will not be invoked from within this function. Invocation
* of the handler will be performed in a manner equivalent to using
* asio::io_context::post().
*
* @note The read operation may not read all of the requested number of bytes.
* Consider using the @ref async_read_at function if you need to ensure that
* the requested amount of data is read before the asynchronous operation
* completes.
*
* @par Example
* To read into a single data buffer use the @ref buffer function as follows:
* @code
* handle.async_read_some_at(42, asio::buffer(data, size), handler);
* @endcode
* See the @ref buffer documentation for information on reading into multiple
* buffers in one go, and how to use it with arrays, boost::array or
* std::vector.
*/
template <typename MutableBufferSequence, typename ReadHandler>
ASIO_INITFN_RESULT_TYPE(ReadHandler,
void (asio::error_code, std::size_t))
async_read_some_at(uint64_t offset,
const MutableBufferSequence& buffers,
ASIO_MOVE_ARG(ReadHandler) handler)
{
// If you get an error on the following line it means that your handler does
// not meet the documented type requirements for a ReadHandler.
ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
asio::async_completion<ReadHandler,
void (asio::error_code, std::size_t)> init(handler);
this->get_service().async_read_some_at(this->get_implementation(),
offset, buffers, init.completion_handler);
return init.result.get();
}
};
#endif // defined(ASIO_ENABLE_OLD_SERVICES)
} // namespace windows
} // namespace asio
#include "asio/detail/pop_options.hpp"
#endif // defined(ASIO_HAS_WINDOWS_RANDOM_ACCESS_HANDLE)
// || defined(GENERATING_DOCUMENTATION)
#endif // ASIO_WINDOWS_RANDOM_ACCESS_HANDLE_HPP
|