// Copyright (c) 2006, 2007 Julio M. Merino Vidal
// Copyright (c) 2008 Ilya Sokolov, Boris Schaeling
// Copyright (c) 2009 Boris Schaeling
// Copyright (c) 2010 Felipe Tanus, Boris Schaeling
// Copyright (c) 2011, 2012 Jeff Flinn, Boris Schaeling
//
// 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_PROCESS_POSIX_EXECUTOR_HPP
#define BOOST_PROCESS_POSIX_EXECUTOR_HPP

#include <boost/process/posix/child.hpp>
#include <boost/fusion/algorithm/iteration/for_each.hpp>
#include <cstdlib>
#include <sys/types.h>
#include <unistd.h>

namespace boost { namespace process { namespace posix {

struct executor
{
    executor() : exe(0), cmd_line(0), env(0) {}

    struct call_on_fork_setup
    {
        executor &e_;

        call_on_fork_setup(executor &e) : e_(e) {}

        template <class Arg>
        void operator()(const Arg &arg) const
        {
            arg.on_fork_setup(e_);
        }
    };

    struct call_on_fork_error
    {
        executor &e_;

        call_on_fork_error(executor &e) : e_(e) {}

        template <class Arg>
        void operator()(Arg &arg) const
        {
            arg.on_fork_error(e_);
        }
    };

    struct call_on_fork_success
    {
        executor &e_;

        call_on_fork_success(executor &e) : e_(e) {}

        template <class Arg>
        void operator()(Arg &arg) const
        {
            arg.on_fork_success(e_);
        }
    };

    struct call_on_exec_setup
    {
        executor &e_;

        call_on_exec_setup(executor &e) : e_(e) {}

        template <class Arg>
        void operator()(Arg &arg) const
        {
            arg.on_exec_setup(e_);
        }
    };

    struct call_on_exec_error
    {
        executor &e_;

        call_on_exec_error(executor &e) : e_(e) {}

        template <class Arg>
        void operator()(Arg &arg) const
        {
            arg.on_exec_error(e_);
        }
    };

    template <class InitializerSequence>
    child operator()(const InitializerSequence &seq)
    {
        boost::fusion::for_each(seq, call_on_fork_setup(*this));

        pid_t pid = ::fork();
        if (pid == -1)
        {
            boost::fusion::for_each(seq, call_on_fork_error(*this));
        }
        else if (pid == 0)
        {
            boost::fusion::for_each(seq, call_on_exec_setup(*this));
            ::execve(exe, cmd_line, env);
            boost::fusion::for_each(seq, call_on_exec_error(*this));
            _exit(EXIT_FAILURE);
        }

        boost::fusion::for_each(seq, call_on_fork_success(*this));

        return child(pid);
    }

    const char *exe;
    char **cmd_line;
    char **env;
};

}}}

#endif