ceph/src/boost/boost/process/async.hpp

   1 // Copyright (c) 2016 Klemens D. Morgenstern
   2 //
   3 // Distributed under the Boost Software License, Version 1.0. (See accompanying
   4 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   5
   6 /** \file boost/process/async.hpp
   7
   8 The header which provides the basic asynchrounous features.
   9 It provides the on_exit property, which allows callbacks when the process exits.
  10 It also implements the necessary traits for passing an boost::asio::io_context,
  11 which is needed for asynchronous communication.
  12
  13 It also pulls the [boost::asio::buffer](http://www.boost.org/doc/libs/release/doc/html/boost_asio/reference/buffer.html)
  14 into the boost::process namespace for convenience.
  15
  16 \xmlonly
  17 <programlisting>
  18 namespace boost {
  19   namespace process {
  20     <emphasis>unspecified</emphasis> <ulink url="http://www.boost.org/doc/libs/1_61_0/doc/html/boost_asio/reference/buffer.html">buffer</ulink>;
  21     <emphasis>unspecified</emphasis> <globalname alt="boost::process::on_exit">on_exit</globalname>;
  22   }
  23 }
  24 </programlisting>
  25
  26 \endxmlonly
  27   */
  28
  29 #ifndef BOOST_PROCESS_ASYNC_HPP_
  30 #define BOOST_PROCESS_ASYNC_HPP_
  31
  32 #include <boost/process/detail/traits.hpp>
  33 #include <boost/process/detail/on_exit.hpp>
  34
  35 #include <boost/asio/io_context.hpp>
  36 #include <boost/asio/streambuf.hpp>
  37 #include <boost/asio/buffer.hpp>
  38 #include <type_traits>
  39 #include <boost/fusion/iterator/deref.hpp>
  40
  41 #if defined(BOOST_POSIX_API)
  42 #include <boost/process/detail/posix/io_context_ref.hpp>
  43 #include <boost/process/detail/posix/async_in.hpp>
  44 #include <boost/process/detail/posix/async_out.hpp>
  45 #include <boost/process/detail/posix/on_exit.hpp>
  46
  47 #elif defined(BOOST_WINDOWS_API)
  48 #include <boost/process/detail/windows/io_context_ref.hpp>
  49 #include <boost/process/detail/windows/async_in.hpp>
  50 #include <boost/process/detail/windows/async_out.hpp>
  51 #include <boost/process/detail/windows/on_exit.hpp>
  52 #endif
  53
  54 namespace boost { namespace process { namespace detail {
  55
  56 struct async_tag;
  57
  58 template<typename T>
  59 struct is_io_context : std::false_type {};
  60 template<>
  61 struct is_io_context<api::io_context_ref> : std::true_type {};
  62
  63 template<typename Tuple>
  64 inline asio::io_context& get_io_context(const Tuple & tup)
  65 {
  66     auto& ref = *boost::fusion::find_if<is_io_context<boost::mpl::_>>(tup);
  67     return ref.get();
  68 }
  69
  70 struct async_builder
  71 {
  72     boost::asio::io_context * ios;
  73
  74     void operator()(boost::asio::io_context & ios_) {this->ios = &ios_;};
  75
  76     typedef api::io_context_ref result_type;
  77     api::io_context_ref get_initializer() {return api::io_context_ref (*ios);};
  78 };
  79
  80
  81 template<>
  82 struct initializer_builder<async_tag>
  83 {
  84     typedef async_builder type;
  85 };
  86
  87 }
  88
  89 using ::boost::asio::buffer;
  90
  91
  92 #if defined(BOOST_PROCESS_DOXYGEN)
  93 /** When an io_context is passed, the on_exit property can be used, to be notified
  94     when the child process exits.
  95
  96
  97 The following syntax is valid
  98
  99 \code{.cpp}
 100 on_exit=function;
 101 on_exit(function);
 102 \endcode
 103
 104 with `function` being a callable object with the signature `(int, const std::error_code&)` or an
 105 `std::future<int>`.
 106
 107 \par Example
 108
 109 \code{.cpp}
 110 io_context ios;
 111
 112 child c("ls", on_exit=[](int exit, const std::error_code& ec_in){});
 113
 114 std::future<int> exit_code;
 115 chlid c2("ls", on_exit=exit_code);
 116
 117 \endcode
 118
 119 \note The handler is not invoked when the launch fails.
 120 \warning When used \ref ignore_error it might get invoked on error.
 121 \warning All `on_exit` use one signal(SIGCHLD) on posix, which is only guaranteed to work when all use the same `io_context`.
 122  */
 123 constexpr static ::boost::process::detail::on_exit_ on_exit{};
 124 #endif
 125
 126 }}
 127
 128
 129
 130 #endif /* INCLUDE_BOOST_PROCESS_DETAIL_ASYNC_HPP_ */