diff options
Diffstat (limited to 'boost/beast/core/file_base.hpp')
| -rw-r--r-- | boost/beast/core/file_base.hpp | 119 |
1 files changed, 97 insertions, 22 deletions
diff --git a/boost/beast/core/file_base.hpp b/boost/beast/core/file_base.hpp index c2b3c53a53..cf75e78579 100644 --- a/boost/beast/core/file_base.hpp +++ b/boost/beast/core/file_base.hpp @@ -1,5 +1,5 @@ // -// Copyright (c) 2015-2016 Vinnie Falco (vinnie dot falco at gmail dot com) +// Copyright (c) 2015-2019 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) @@ -11,42 +11,63 @@ #define BOOST_BEAST_CORE_FILE_BASE_HPP #include <boost/beast/core/detail/config.hpp> -#include <boost/beast/core/string.hpp> +#include <boost/beast/core/error.hpp> +#include <boost/type_traits/make_void.hpp> +#include <type_traits> namespace boost { namespace beast { +/* + +file_mode acesss sharing seeking file std mode +-------------------------------------------------------------------------------------- +read read-only shared random must exist "rb" +scan read-only shared sequential must exist "rbS" +write read/write exclusive random create/truncate "wb+" +write_new read/write exclusive random must not exist "wbx" +write_existing read/write exclusive random must exist "rb+" +append write-only exclusive sequential create/truncate "ab" +append_existing write-only exclusive sequential must exist "ab" + +*/ + /** File open modes These modes are used when opening files using - instances of the @b File concept. + instances of the <em>File</em> concept. @see file_stdio */ enum class file_mode { - /// Random reading + /// Random read-only access to an existing file read, - /// Sequential reading + /// Sequential read-only access to an existing file scan, - /** Random writing to a new or truncated file - - @li If the file does not exist, it is created. + /** Random reading and writing to a new or truncated file - @li If the file exists, it is truncated to - zero size upon opening. + This mode permits random-access reading and writing + for the specified file. If the file does not exist + prior to the function call, it is created with an + initial size of zero bytes. Otherwise if the file + already exists, the size is truncated to zero bytes. */ write, - /** Random writing to new file only + /** Random reading and writing to a new file only - If the file exists, an error is generated. + This mode permits random-access reading and writing + for the specified file. The file will be created with + an initial size of zero bytes. If the file already exists + prior to the function call, an error is returned and + no file is opened. */ write_new, - /** Random writing to existing file + /** Random write-only access to existing file If the file does not exist, an error is generated. */ @@ -64,15 +85,6 @@ enum class file_mode */ append, - /** Appending to a new file only - - The current file position shall be set to the end of - the file prior to each write. - - If the file exists, an error is generated. - */ - append_new, - /** Appending to an existing file The current file position shall be set to the end of @@ -83,6 +95,69 @@ enum class file_mode append_existing }; +/** Determine if `T` meets the requirements of <em>File</em>. + + Metafunctions are used to perform compile time checking of template + types. This type will be `std::true_type` if `T` meets the requirements, + else the type will be `std::false_type`. + + @par Example + + Use with `static_assert`: + + @code + template<class File> + void f(File& file) + { + static_assert(is_file<File>::value, + "File type requirements not met"); + ... + @endcode + + Use with `std::enable_if` (SFINAE): + + @code + template<class File> + typename std::enable_if<is_file<File>::value>::type + f(File& file); + @endcode +*/ +#if BOOST_BEAST_DOXYGEN +template<class T> +struct is_file : std::integral_constant<bool, ...>{}; +#else +template<class T, class = void> +struct is_file : std::false_type {}; + +template<class T> +struct is_file<T, boost::void_t<decltype( + std::declval<bool&>() = std::declval<T const&>().is_open(), + std::declval<T&>().close(std::declval<error_code&>()), + std::declval<T&>().open( + std::declval<char const*>(), + std::declval<file_mode>(), + std::declval<error_code&>()), + std::declval<std::uint64_t&>() = std::declval<T&>().size( + std::declval<error_code&>()), + std::declval<std::uint64_t&>() = std::declval<T&>().pos( + std::declval<error_code&>()), + std::declval<T&>().seek( + std::declval<std::uint64_t>(), + std::declval<error_code&>()), + std::declval<std::size_t&>() = std::declval<T&>().read( + std::declval<void*>(), + std::declval<std::size_t>(), + std::declval<error_code&>()), + std::declval<std::size_t&>() = std::declval<T&>().write( + std::declval<void const*>(), + std::declval<std::size_t>(), + std::declval<error_code&>()) + )>> : std::integral_constant<bool, + std::is_default_constructible<T>::value && + std::is_destructible<T>::value + > {}; +#endif + } // beast } // boost |