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편집 파일: basic_stream_file.hpp

// // basic_stream_file.hpp // ~~~~~~~~~~~~~~~~~~~~~ // // Copyright (c) 2003-2024 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_BASIC_STREAM_FILE_HPP #define BOOST_ASIO_BASIC_STREAM_FILE_HPP #if defined(_MSC_VER) && (_MSC_VER >= 1200) # pragma once #endif // defined(_MSC_VER) && (_MSC_VER >= 1200) #include <boost/asio/detail/config.hpp> #if defined(BOOST_ASIO_HAS_FILE) \ || defined(GENERATING_DOCUMENTATION) #include <cstddef> #include <boost/asio/async_result.hpp> #include <boost/asio/basic_file.hpp> #include <boost/asio/detail/handler_type_requirements.hpp> #include <boost/asio/detail/non_const_lvalue.hpp> #include <boost/asio/detail/throw_error.hpp> #include <boost/asio/error.hpp> #include <boost/asio/detail/push_options.hpp> namespace boost { namespace asio { #if !defined(BOOST_ASIO_BASIC_STREAM_FILE_FWD_DECL) #define BOOST_ASIO_BASIC_STREAM_FILE_FWD_DECL // Forward declaration with defaulted arguments. template <typename Executor = any_io_executor> class basic_stream_file; #endif // !defined(BOOST_ASIO_BASIC_STREAM_FILE_FWD_DECL) /// Provides stream-oriented file functionality. /** * The basic_stream_file class template provides asynchronous and blocking * stream-oriented file functionality. * * @par Thread Safety * @e Distinct @e objects: Safe.@n * @e Shared @e objects: Unsafe. * * @par Concepts: * AsyncReadStream, AsyncWriteStream, Stream, SyncReadStream, SyncWriteStream. */ template <typename Executor> class basic_stream_file : public basic_file<Executor> { private: class initiate_async_write_some; class initiate_async_read_some; public: /// The type of the executor associated with the object. typedef Executor executor_type; /// Rebinds the file type to another executor. template <typename Executor1> struct rebind_executor { /// The file type when rebound to the specified executor. typedef basic_stream_file<Executor1> other; }; /// The native representation of a file. #if defined(GENERATING_DOCUMENTATION) typedef implementation_defined native_handle_type; #else typedef typename basic_file<Executor>::native_handle_type native_handle_type; #endif /// Construct a basic_stream_file without opening it. /** * This constructor initialises a file without opening it. The file needs to * be opened before data can be read from or or written to it. * * @param ex The I/O executor that the file will use, by default, to * dispatch handlers for any asynchronous operations performed on the file. */ explicit basic_stream_file(const executor_type& ex) : basic_file<Executor>(ex) { this->impl_.get_service().set_is_stream( this->impl_.get_implementation(), true); } /// Construct a basic_stream_file without opening it. /** * This constructor initialises a file without opening it. The file needs to * be opened before data can be read from or or written to it. * * @param context An execution context which provides the I/O executor that * the file will use, by default, to dispatch handlers for any asynchronous * operations performed on the file. */ template <typename ExecutionContext> explicit basic_stream_file(ExecutionContext& context, constraint_t< is_convertible<ExecutionContext&, execution_context&>::value, defaulted_constraint > = defaulted_constraint()) : basic_file<Executor>(context) { this->impl_.get_service().set_is_stream( this->impl_.get_implementation(), true); } /// Construct and open a basic_stream_file. /** * This constructor initialises and opens a file. * * @param ex The I/O executor that the file will use, by default, to * dispatch handlers for any asynchronous operations performed on the file. * * @param path The path name identifying the file to be opened. * * @param open_flags A set of flags that determine how the file should be * opened. * * @throws boost::system::system_error Thrown on failure. */ basic_stream_file(const executor_type& ex, const char* path, file_base::flags open_flags) : basic_file<Executor>(ex) { boost::system::error_code ec; this->impl_.get_service().set_is_stream( this->impl_.get_implementation(), true); this->impl_.get_service().open( this->impl_.get_implementation(), path, open_flags, ec); boost::asio::detail::throw_error(ec, "open"); } /// Construct and open a basic_stream_file. /** * This constructor initialises and opens a file. * * @param context An execution context which provides the I/O executor that * the file will use, by default, to dispatch handlers for any asynchronous * operations performed on the file. * * @param path The path name identifying the file to be opened. * * @param open_flags A set of flags that determine how the file should be * opened. * * @throws boost::system::system_error Thrown on failure. */ template <typename ExecutionContext> basic_stream_file(ExecutionContext& context, const char* path, file_base::flags open_flags, constraint_t< is_convertible<ExecutionContext&, execution_context&>::value, defaulted_constraint > = defaulted_constraint()) : basic_file<Executor>(context) { boost::system::error_code ec; this->impl_.get_service().set_is_stream( this->impl_.get_implementation(), true); this->impl_.get_service().open( this->impl_.get_implementation(), path, open_flags, ec); boost::asio::detail::throw_error(ec, "open"); } /// Construct and open a basic_stream_file. /** * This constructor initialises and opens a file. * * @param ex The I/O executor that the file will use, by default, to * dispatch handlers for any asynchronous operations performed on the file. * * @param path The path name identifying the file to be opened. * * @param open_flags A set of flags that determine how the file should be * opened. * * @throws boost::system::system_error Thrown on failure. */ basic_stream_file(const executor_type& ex, const std::string& path, file_base::flags open_flags) : basic_file<Executor>(ex) { boost::system::error_code ec; this->impl_.get_service().set_is_stream( this->impl_.get_implementation(), true); this->impl_.get_service().open( this->impl_.get_implementation(), path.c_str(), open_flags, ec); boost::asio::detail::throw_error(ec, "open"); } /// Construct and open a basic_stream_file. /** * This constructor initialises and opens a file. * * @param context An execution context which provides the I/O executor that * the file will use, by default, to dispatch handlers for any asynchronous * operations performed on the file. * * @param path The path name identifying the file to be opened. * * @param open_flags A set of flags that determine how the file should be * opened. * * @throws boost::system::system_error Thrown on failure. */ template <typename ExecutionContext> basic_stream_file(ExecutionContext& context, const std::string& path, file_base::flags open_flags, constraint_t< is_convertible<ExecutionContext&, execution_context&>::value, defaulted_constraint > = defaulted_constraint()) : basic_file<Executor>(context) { boost::system::error_code ec; this->impl_.get_service().set_is_stream( this->impl_.get_implementation(), true); this->impl_.get_service().open( this->impl_.get_implementation(), path.c_str(), open_flags, ec); boost::asio::detail::throw_error(ec, "open"); } /// Construct a basic_stream_file on an existing native file. /** * This constructor initialises a stream file object to hold an existing * native file. * * @param ex The I/O executor that the file will use, by default, to * dispatch handlers for any asynchronous operations performed on the file. * * @param native_file The new underlying file implementation. * * @throws boost::system::system_error Thrown on failure. */ basic_stream_file(const executor_type& ex, const native_handle_type& native_file) : basic_file<Executor>(ex, native_file) { this->impl_.get_service().set_is_stream( this->impl_.get_implementation(), true); } /// Construct a basic_stream_file on an existing native file. /** * This constructor initialises a stream file object to hold an existing * native file. * * @param context An execution context which provides the I/O executor that * the file will use, by default, to dispatch handlers for any asynchronous * operations performed on the file. * * @param native_file The new underlying file implementation. * * @throws boost::system::system_error Thrown on failure. */ template <typename ExecutionContext> basic_stream_file(ExecutionContext& context, const native_handle_type& native_file, constraint_t< is_convertible<ExecutionContext&, execution_context&>::value, defaulted_constraint > = defaulted_constraint()) : basic_file<Executor>(context, native_file) { this->impl_.get_service().set_is_stream( this->impl_.get_implementation(), true); } /// Move-construct a basic_stream_file from another. /** * This constructor moves a stream file from one object to another. * * @param other The other basic_stream_file 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_stream_file(const executor_type&) * constructor. */ basic_stream_file(basic_stream_file&& other) noexcept : basic_file<Executor>(std::move(other)) { } /// Move-assign a basic_stream_file from another. /** * This assignment operator moves a stream file from one object to another. * * @param other The other basic_stream_file 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_stream_file(const executor_type&) * constructor. */ basic_stream_file& operator=(basic_stream_file&& other) { basic_file<Executor>::operator=(std::move(other)); return *this; } /// Move-construct a basic_stream_file from a file of another executor /// type. /** * This constructor moves a stream file from one object to another. * * @param other The other basic_stream_file 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_stream_file(const executor_type&) * constructor. */ template <typename Executor1> basic_stream_file(basic_stream_file<Executor1>&& other, constraint_t< is_convertible<Executor1, Executor>::value, defaulted_constraint > = defaulted_constraint()) : basic_file<Executor>(std::move(other)) { } /// Move-assign a basic_stream_file from a file of another executor type. /** * This assignment operator moves a stream file from one object to another. * * @param other The other basic_stream_file 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_stream_file(const executor_type&) * constructor. */ template <typename Executor1> constraint_t< is_convertible<Executor1, Executor>::value, basic_stream_file& > operator=(basic_stream_file<Executor1>&& other) { basic_file<Executor>::operator=(std::move(other)); return *this; } /// Destroys the file. /** * This function destroys the file, cancelling any outstanding asynchronous * operations associated with the file as if by calling @c cancel. */ ~basic_stream_file() { } /// Seek to a position in the file. /** * This function updates the current position in the file. * * @param offset The requested position in the file, relative to @c whence. * * @param whence One of @c seek_set, @c seek_cur or @c seek_end. * * @returns The new position relative to the beginning of the file. * * @throws boost::system::system_error Thrown on failure. */ uint64_t seek(int64_t offset, file_base::seek_basis whence) { boost::system::error_code ec; uint64_t n = this->impl_.get_service().seek( this->impl_.get_implementation(), offset, whence, ec); boost::asio::detail::throw_error(ec, "seek"); return n; } /// Seek to a position in the file. /** * This function updates the current position in the file. * * @param offset The requested position in the file, relative to @c whence. * * @param whence One of @c seek_set, @c seek_cur or @c seek_end. * * @param ec Set to indicate what error occurred, if any. * * @returns The new position relative to the beginning of the file. */ uint64_t seek(int64_t offset, file_base::seek_basis whence, boost::system::error_code& ec) { return this->impl_.get_service().seek( this->impl_.get_implementation(), offset, whence, ec); } /// Write some data to the file. /** * This function is used to write data to the stream file. The function call * will block until one or more bytes of the data has been written * successfully, or until an error occurs. * * @param buffers One or more data buffers to be written to the file. * * @returns The number of bytes written. * * @throws boost::system::system_error Thrown on failure. An error code of * boost::asio::error::eof indicates that the end of the file was reached. * * @note The write_some operation may not transmit all of the data to the * peer. Consider using the @ref write 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 * file.write_some(boost::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(const ConstBufferSequence& buffers) { boost::system::error_code ec; std::size_t s = this->impl_.get_service().write_some( this->impl_.get_implementation(), buffers, ec); boost::asio::detail::throw_error(ec, "write_some"); return s; } /// Write some data to the file. /** * This function is used to write data to the stream file. The function call * will block until one or more bytes of the data has been written * successfully, or until an error occurs. * * @param buffers One or more data buffers to be written to the file. * * @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 function if you need to ensure that * all data is written before the blocking operation completes. */ template <typename ConstBufferSequence> std::size_t write_some(const ConstBufferSequence& buffers, boost::system::error_code& ec) { return this->impl_.get_service().write_some( this->impl_.get_implementation(), buffers, ec); } /// Start an asynchronous write. /** * This function is used to asynchronously write data to the stream file. * It is an initiating function for an @ref asynchronous_operation, and always * returns immediately. * * @param buffers One or more data buffers to be written to the file. * 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 completion handler is called. * * @param token The @ref completion_token that will be used to produce a * completion handler, which will be called when the write 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. * std::size_t bytes_transferred // Number of bytes written. * ); @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(). * * @par Completion Signature * @code void(boost::system::error_code, std::size_t) @endcode * * @note The write operation may not transmit all of the data to the peer. * Consider using the @ref async_write 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 * file.async_write_some(boost::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. * * @par Per-Operation Cancellation * On POSIX or Windows operating systems, this asynchronous operation supports * cancellation for the following boost::asio::cancellation_type values: * * @li @c cancellation_type::terminal * * @li @c cancellation_type::partial * * @li @c cancellation_type::total */ template <typename ConstBufferSequence, BOOST_ASIO_COMPLETION_TOKEN_FOR(void (boost::system::error_code, std::size_t)) WriteToken = default_completion_token_t<executor_type>> auto async_write_some(const ConstBufferSequence& buffers, WriteToken&& token = default_completion_token_t<executor_type>()) -> decltype( async_initiate<WriteToken, void (boost::system::error_code, std::size_t)>( declval<initiate_async_write_some>(), token, buffers)) { return async_initiate<WriteToken, void (boost::system::error_code, std::size_t)>( initiate_async_write_some(this), token, buffers); } /// Read some data from the file. /** * This function is used to read data from the stream file. The function * call will block until one or more bytes of data has been read successfully, * or until an error occurs. * * @param buffers One or more buffers into which the data will be read. * * @returns The number of bytes read. * * @throws boost::system::system_error Thrown on failure. An error code of * boost::asio::error::eof indicates that the end of the file was reached. * * @note The read_some operation may not read all of the requested number of * bytes. Consider using the @ref read 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 * file.read_some(boost::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(const MutableBufferSequence& buffers) { boost::system::error_code ec; std::size_t s = this->impl_.get_service().read_some( this->impl_.get_implementation(), buffers, ec); boost::asio::detail::throw_error(ec, "read_some"); return s; } /// Read some data from the file. /** * This function is used to read data from the stream file. The function * call will block until one or more bytes of data has been read successfully, * or until an error occurs. * * @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 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(const MutableBufferSequence& buffers, boost::system::error_code& ec) { return this->impl_.get_service().read_some( this->impl_.get_implementation(), buffers, ec); } /// Start an asynchronous read. /** * This function is used to asynchronously read data from the stream file. * It is an initiating function for an @ref asynchronous_operation, and always * returns immediately. * * @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 completion handler is called. * * @param token The @ref completion_token that will be used to produce a * completion handler, which will be called when the read 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. * std::size_t bytes_transferred // Number of bytes read. * ); @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(). * * @par Completion Signature * @code void(boost::system::error_code, std::size_t) @endcode * * @note The read operation may not read all of the requested number of bytes. * Consider using the @ref async_read 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 * file.async_read_some(boost::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. * * @par Per-Operation Cancellation * On POSIX or Windows operating systems, this asynchronous operation supports * cancellation for the following boost::asio::cancellation_type values: * * @li @c cancellation_type::terminal * * @li @c cancellation_type::partial * * @li @c cancellation_type::total */ template <typename MutableBufferSequence, BOOST_ASIO_COMPLETION_TOKEN_FOR(void (boost::system::error_code, std::size_t)) ReadToken = default_completion_token_t<executor_type>> auto async_read_some(const MutableBufferSequence& buffers, ReadToken&& token = default_completion_token_t<executor_type>()) -> decltype( async_initiate<ReadToken, void (boost::system::error_code, std::size_t)>( declval<initiate_async_read_some>(), token, buffers)) { return async_initiate<ReadToken, void (boost::system::error_code, std::size_t)>( initiate_async_read_some(this), token, buffers); } private: // Disallow copying and assignment. basic_stream_file(const basic_stream_file&) = delete; basic_stream_file& operator=(const basic_stream_file&) = delete; class initiate_async_write_some { public: typedef Executor executor_type; explicit initiate_async_write_some(basic_stream_file* self) : self_(self) { } const executor_type& get_executor() const noexcept { return self_->get_executor(); } template <typename WriteHandler, typename ConstBufferSequence> void operator()(WriteHandler&& handler, const ConstBufferSequence& buffers) const { // If you get an error on the following line it means that your handler // does not meet the documented type requirements for a WriteHandler. BOOST_ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check; detail::non_const_lvalue<WriteHandler> handler2(handler); self_->impl_.get_service().async_write_some( self_->impl_.get_implementation(), buffers, handler2.value, self_->impl_.get_executor()); } private: basic_stream_file* self_; }; class initiate_async_read_some { public: typedef Executor executor_type; explicit initiate_async_read_some(basic_stream_file* self) : self_(self) { } const executor_type& get_executor() const noexcept { return self_->get_executor(); } template <typename ReadHandler, typename MutableBufferSequence> void operator()(ReadHandler&& handler, const MutableBufferSequence& buffers) const { // If you get an error on the following line it means that your handler // does not meet the documented type requirements for a ReadHandler. BOOST_ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check; detail::non_const_lvalue<ReadHandler> handler2(handler); self_->impl_.get_service().async_read_some( self_->impl_.get_implementation(), buffers, handler2.value, self_->impl_.get_executor()); } private: basic_stream_file* self_; }; }; } // namespace asio } // namespace boost #include <boost/asio/detail/pop_options.hpp> #endif // defined(BOOST_ASIO_HAS_FILE) // || defined(GENERATING_DOCUMENTATION) #endif // BOOST_ASIO_BASIC_STREAM_FILE_HPP