ceph/src/boost/boost/beast/core/file_stdio.hpp

   1 //
   2 // Copyright (c) 2015-2019 Vinnie Falco (vinnie dot falco at gmail dot com)
   3 //
   4 // Distributed under the Boost Software License, Version 1.0. (See accompanying
   5 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   6 //
   7 // Official repository: https://github.com/boostorg/beast
   8 //
   9
  10 #ifndef BOOST_BEAST_CORE_FILE_STDIO_HPP
  11 #define BOOST_BEAST_CORE_FILE_STDIO_HPP
  12
  13 #include <boost/beast/core/detail/config.hpp>
  14 #include <boost/beast/core/error.hpp>
  15 #include <boost/beast/core/file_base.hpp>
  16 #include <cstdio>
  17 #include <cstdint>
  18
  19 namespace boost {
  20 namespace beast {
  21
  22 /** An implementation of File which uses cstdio.
  23
  24     This class implements a file using the interfaces present
  25     in the C++ Standard Library, in `<stdio>`.
  26 */
  27 class file_stdio
  28 {
  29     std::FILE* f_ = nullptr;
  30
  31 public:
  32     /** The type of the underlying file handle.
  33
  34         This is platform-specific.
  35     */
  36     using native_handle_type = std::FILE*;
  37
  38     /** Destructor
  39
  40         If the file is open it is first closed.
  41     */
  42     BOOST_BEAST_DECL
  43     ~file_stdio();
  44
  45     /** Constructor
  46
  47         There is no open file initially.
  48     */
  49     file_stdio() = default;
  50
  51     /** Constructor
  52
  53         The moved-from object behaves as if default constructed.
  54     */
  55     BOOST_BEAST_DECL
  56     file_stdio(file_stdio&& other);
  57
  58     /** Assignment
  59
  60         The moved-from object behaves as if default constructed.
  61     */
  62     BOOST_BEAST_DECL
  63     file_stdio& operator=(file_stdio&& other);
  64
  65     /// Returns the native handle associated with the file.
  66     std::FILE*
  67     native_handle() const
  68     {
  69         return f_;
  70     }
  71
  72     /** Set the native handle associated with the file.
  73
  74         If the file is open it is first closed.
  75
  76         @param f The native file handle to assign.
  77     */
  78     BOOST_BEAST_DECL
  79     void
  80     native_handle(std::FILE* f);
  81
  82     /// Returns `true` if the file is open
  83     bool
  84     is_open() const
  85     {
  86         return f_ != nullptr;
  87     }
  88
  89     /** Close the file if open
  90
  91         @param ec Set to the error, if any occurred.
  92     */
  93     BOOST_BEAST_DECL
  94     void
  95     close(error_code& ec);
  96
  97     /** Open a file at the given path with the specified mode
  98
  99         @param path The utf-8 encoded path to the file
 100
 101         @param mode The file mode to use
 102
 103         @param ec Set to the error, if any occurred
 104     */
 105     BOOST_BEAST_DECL
 106     void
 107     open(char const* path, file_mode mode, error_code& ec);
 108
 109     /** Return the size of the open file
 110
 111         @param ec Set to the error, if any occurred
 112
 113         @return The size in bytes
 114     */
 115     BOOST_BEAST_DECL
 116     std::uint64_t
 117     size(error_code& ec) const;
 118
 119     /** Return the current position in the open file
 120
 121         @param ec Set to the error, if any occurred
 122
 123         @return The offset in bytes from the beginning of the file
 124     */
 125     BOOST_BEAST_DECL
 126     std::uint64_t
 127     pos(error_code& ec) const;
 128
 129     /** Adjust the current position in the open file
 130
 131         @param offset The offset in bytes from the beginning of the file
 132
 133         @param ec Set to the error, if any occurred
 134     */
 135     BOOST_BEAST_DECL
 136     void
 137     seek(std::uint64_t offset, error_code& ec);
 138
 139     /** Read from the open file
 140
 141         @param buffer The buffer for storing the result of the read
 142
 143         @param n The number of bytes to read
 144
 145         @param ec Set to the error, if any occurred
 146     */
 147     BOOST_BEAST_DECL
 148     std::size_t
 149     read(void* buffer, std::size_t n, error_code& ec) const;
 150
 151     /** Write to the open file
 152
 153         @param buffer The buffer holding the data to write
 154
 155         @param n The number of bytes to write
 156
 157         @param ec Set to the error, if any occurred
 158     */
 159     BOOST_BEAST_DECL
 160     std::size_t
 161     write(void const* buffer, std::size_t n, error_code& ec);
 162 };
 163
 164 } // beast
 165 } // boost
 166
 167 #ifdef BOOST_BEAST_HEADER_ONLY
 168 #include <boost/beast/core/impl/file_stdio.ipp>
 169 #endif
 170
 171 #endif