ceph/src/Beast/examples/file_body.hpp

   1 //
   2 // Copyright (c) 2013-2017 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
   8 #ifndef BEAST_EXAMPLE_FILE_BODY_H_INCLUDED
   9 #define BEAST_EXAMPLE_FILE_BODY_H_INCLUDED
  10
  11 #include <beast/core/error.hpp>
  12 #include <beast/http/message.hpp>
  13 #include <boost/asio/buffer.hpp>
  14 #include <boost/assert.hpp>
  15 #include <boost/filesystem.hpp>
  16 #include <cstdio>
  17 #include <cstdint>
  18
  19 namespace beast {
  20 namespace http {
  21
  22 struct file_body
  23 {
  24     using value_type = std::string;
  25
  26     class writer
  27     {
  28         std::uint64_t size_ = 0;
  29         std::uint64_t offset_ = 0;
  30         std::string const& path_;
  31         FILE* file_ = nullptr;
  32         char buf_[4096];
  33         std::size_t buf_len_;
  34
  35     public:
  36         writer(writer const&) = delete;
  37         writer& operator=(writer const&) = delete;
  38
  39         template<bool isRequest, class Fields>
  40         writer(message<isRequest,
  41                 file_body, Fields> const& m) noexcept
  42             : path_(m.body)
  43         {
  44         }
  45
  46         ~writer()
  47         {
  48             if(file_)
  49                 fclose(file_);
  50         }
  51
  52         void
  53         init(error_code& ec) noexcept
  54         {
  55             file_ = fopen(path_.c_str(), "rb");
  56             if(! file_)
  57                 ec = error_code{errno,
  58                     system_category()};
  59             else
  60                 size_ = boost::filesystem::file_size(path_);
  61         }
  62
  63         std::uint64_t
  64         content_length() const noexcept
  65         {
  66             return size_;
  67         }
  68
  69         template<class WriteFunction>
  70         bool
  71         write(error_code& ec, WriteFunction&& wf) noexcept
  72         {
  73             if(size_ - offset_ < sizeof(buf_))
  74                 buf_len_ = static_cast<std::size_t>(
  75                     size_ - offset_);
  76             else
  77                 buf_len_ = sizeof(buf_);
  78             auto const nread = fread(
  79                 buf_, 1, sizeof(buf_), file_);
  80             if(ferror(file_))
  81             {
  82                 ec = error_code(errno,
  83                     system_category());
  84                 return true;
  85             }
  86             BOOST_ASSERT(nread != 0);
  87             offset_ += nread;
  88             wf(boost::asio::buffer(buf_, nread));
  89             return offset_ >= size_;
  90         }
  91     };
  92 };
  93
  94 } // http
  95 } // beast
  96
  97 #endif